Note: Descriptions are shown in the official language in which they were submitted.
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IMPROVEMENTS IN WASTEWATER EVAPORATION SYSTEMS
FIELD OF THE INVENTION
[0001] The invention relates to methods, systems and apparatus for
distributed
management of raw water, heat energy within combustion gas and internal
combustion engine
(ICE) gas heat and pressure generated during industrial operations. Such
operations include but
are not limited to oilfield drilling, completions and production operations
with mobile, semi-
permanent and/or permanent processing units. One aspect of the invention
provides a compact,
concentrator, vaporizer and demister. The apparatus can be configured in
various embodiments
and can provide various advantages to operators seeking to vaporize raw water
and/or
concentrate contaminants within raw water using waste heat and/or pressure
from such
operations including ICE's and other sources, such as flare stacks,
incinerators, steam
generators or natural gas turbines. These advantages can include:
a. low maintenance through the design and operation of a system that minimizes
scale, particulate, salts and other build-up;
b. minimal new energy input over and above a primary heat source such as an
ICE,
combustion gas, flare gas or other similar source;
c. minimal pressure drop related to water vaporization and/or entrainment
separation;
d. maximization use of available waste pressure and/or heat;
e. effective and maximized use of low grade waste heat not typically suitable
or
accessible;
f. reduce the release of volatiles and pollutants to the atmosphere;
g. recovery of condensates/concentrates from raw water;
h. reduced capital cost of raw water vaporization equipment;
i. reduced ongoing operating expense due to minimized need for operator
oversight;
j. light weight and compact system for remote or satellite installations
closer to a
heat source;
k. light weight and compact system that can be made with plastics allowing
rapid
mass production and the ability to custom manufacture various embodiments;
I. a monitoring and reporting system for remote management of many distributed
systems within a larger grid;
m. reduced ground level footprint when installed or retrofit to existing
oilfield
equipment.
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[0002] The system may help allow many economical and environmentally
positive
alternatives over historical raw water management techniques and can
substantially limit
atmospheric discharge of contaminants entrained within ICE combustion gas.
Advantageously
the invention simultaneously facilitates rapid transfer of combustion gas
particulate chemicals
into the raw water as it concentrates. Another aspect of the invention is an
exhaust diversion
system to provide energy within exhaust, i.e. heat and pressure, to a dual
fluid interaction zone
within the system.
[0003] Another aspect of the invention is that due to some of its various
features and
benefits such as being compact, in-line and/or self-cleaning it can be placed
at or near to a
waste heat source minimizing the need for ground level footprint. A further
aspect of the
invention provides an economically viable and environmentally synergistic
means of distributed
raw water and emissions management to reduce and recycle large volumes of
industrial raw
water and emissions within localized regions, often remote and stranded from
waste
management infrastructure, in which both raw water and emissions are
generated, are in
abundance and are considered waste by-products of industrial operations.
Distributed
management of raw water and emissions may be enhanced by networking data from
these
remote raw water management processing units as a means to ensure that each
satellite
system in the network can be utilized to its full capacity either by actors
within an organization
operating within a geographic region or by many organizations operating within
a geographic
region utilizing each other's raw water processing system.
[0004] An algorithm may be used as a means to communicate data points to
those
within the network such as individual system run time, raw water processing
rates, available or
unused capacity of raw water, re-condensed water, heat, pressure, brine, salt,
etc., timing
and/or availability of upcoming spare capacity, etc. As described herein part
of the novelty of the
present invention is its simplicity.
BACKGROUND OF THE INVENTION
[0005] There are many examples where vaporization is used to reduce the
liquid phase
of water solutions containing contaminants for the purpose of concentrating
the contaminants
for disposal. Often referred to as thermal separation or thermal concentration
processes, these
processes generally begin with a liquid and end up with a more concentrated
but still pump-able
concentrate or a dry salt that may be subjected to further processing and/or
disposal. In the
context of this description, waste water solutions containing dissolved and/or
suspended
contaminants are referred to as "raw water" or "wastewater". In particular,
raw water refers to
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water solutions containing contaminants, for example, brackish or brine fluid
(including sodium,
potassium, calcium and other salts) and some particulates. Other contaminants
including
hydrocarbons (generally 05 and higher), soaps and particulates may also be
within the raw
water. The concentrations of contaminants within the raw water may range, in
the case of salts
from about 0 to about 25 wt%, in the case of hydrocarbons from about 0 to
about 5 wt%, in the
case of soaps from about 0 to about 2 wt%.
[0006] Raw water may be production water from a gas or liquid hydrocarbon
production
facility where the raw water has been separated from a gas or liquid
hydrocarbon production
stream. In this instance, the raw water may include connate water, connate
water salts and
particulates together with hydrocarbons. Raw water may also be raw water from
drilling
operations including cement water, wash water, contaminated lease water,
drilling fluid, water
from recovered drilling fluids which may include connate water, connate water
salts,
emulsifiers/soaps, viscosifying agents, hydrocarbons and particulates and
others.
[0007] As is generally known with aqueous concentrator systems, as water
vapor is
vaporized, the concentrate progressively comprises increasing percentages of
the original
contaminants in the solution including the salts, hydrocarbons and
particulates. Due to the
nature of different contaminants, as the solutions become more concentrated,
there has been a
need for systems and methods that can effectively manage the solutions as the
contaminants
become more concentrated.
[0008] In the case of dilute solutions containing hydrocarbons, that may
include heavy
oil, medium oil and light oil fractions, the handling of such solutions must
be managed in order
to enable operators to collect what might be valuable amounts of these
hydrocarbons but also to
prevent flammable solutions from being created particularly in locations where
heat and oxygen
may be present in the concentrator system. For example, a feed or raw water
solution with 1%
condensate concentration may result in a 10% (or higher) condensate solution
over time as
water is vaporized from the solution which may represent a sufficiently
valuable volume to
warrant collection but also that could become a potentially flammable mixture
wherein the
hydrocarbons should be removed.
[0009] Similarly, in the case of a brackish wastewater solution having a
1-2% salt
concentration or brine wastewater solutions having a 4-20% salt concentration,
the solution will
become progressively more concentrated with salt up to a point where the
solution becomes
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fully saturated with the salt and will precipitate from the solution. As a
result, there has been a
need for systems and methods that can effectively manage concentrated salt
solutions that do
not lead to scaling within the equipment that will require maintenance and/or
precipitates that
could cause clogging of lines. Moreover, as the solubility of many salts
varies as a function of
temperature, there has been a need for concentration systems that can maintain
consistent
temperatures to minimize precipitation issues that may occur as temperatures
vary within a
system.
[0010] Particulates in a typical wastewater solution may range in size
from about 0.2
microns (fine clay or silt particles) to about 500-1,000 microns (sand and
gravel particles) and
may comprise from about 0 to about 10 wt% of the raw water solution. As with
other
contaminants, particulates will become more concentrated during the
concentration processes.
While larger particles are generally easily removed, finer particles can
become increasingly
problematic within the concentrating solutions as viscosity increases and
increasingly larger
particles may become suspended in the solution and can lead to scaling and/or
plugging of
lines. As such, there has been a need for systems and methods that minimize
the effect of
particulates.
[0011] In addition, there has also been a need for a system with the
capability to
concentrate waste water using waste heat and waste pressure, pushed by
mechanical force of
engine pistons. These can be generated from remote or stranded industrial
operations, such as
drilling rig operations, and there has been a need to provide further
operational and efficiency
advantages over systems that use standalone hydrocarbon (e.g. fuels) and/or
electric sources
as prime energy inputs and that add to the cost of vaporizing and/or
processing raw water.
[0012] Further still, there is also a need for a system that is also
simultaneously effective
in vaporizing water and removing combustion related soot, particulate and
combustion
chemicals from the combustion gas source of the particular heating source. In
other words,
heretofore there has been no incentive for mobile treatment of flue gasses on
remote or
stranded drilling sites because there are local and national exemptions to
standard air emission
regulations on oil and gas drilling sites related to diesel engine exhaust
volume and
concentration of discharge within relatively short timeframes. As such, until
an economical and
functional solution is provided, enabling regulators and operators to insist
on change, the
cleaning of these collectively large volumes of acid gasses prior to
atmospheric discharge will
not occur. Accordingly, by marrying the technology for cleaning exhaust gasses
with another
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use such as vaporizing raw water, there is an economic incentive to the
operator to take this
environmentally responsible action.
[0013] In regards to the emissions from drilling rig operations, in
recent years as many
as 2,000 rigs have been operating in North America each day with each one
consuming on
average approximately 3,000 ¨ 9,000 liters per day of diesel fuel within the
various power
generating machinery. For example, a typical 500kW engine-generator set at a
drilling site will
exhaust 50 to 120 m3/min whereas a 1200kW engine-generator set produces in the
order of 273
m3/min of acid gas exhaust into the environment thereby polluting the
environment and wasting
the heat and pressure energy contained therein. However, the heat contained
within this
exhaust is capable of vaporizing up to about 10 cubic meters of water per day
depending on
average engine load through-out the day. This equates to 95-285 billion cubic
meters of
uncleaned acid gas discharge from all North American rigs every year and a
heat/pressure
resource that is otherwise unutilized. As can be imaged when 1200-2500 kW
engine-generator
sets are used for these operations, the amount of waste heat and waste
pressure are much
larger and become substantial sources of free prime mover energy input.
[0014] Thus, there has also been a need for systems that can reduce the
amount of
exhaust contaminants that may be released to the atmosphere while at the same
time using that
heat/pressure resource for reducing the total volumes of contaminated waste
water that
requiring shipping and/or removal from a drilling rig site, in-ground
injection or the like.
[0015] Other oilfield operations include heavy oil production through
steam injection,
including steam assisted gravity drainage (SAGD), and gas production where
large quantities of
water are utilized within and recovered from heavy oil reservoirs. Water will
be recovered from
the reservoir with varying contaminants and concentrations of contaminants.
For example,
steam injection techniques result in the production of mixtures of produced
water (containing
sodium and calcium salts inter alia) and hydrocarbons (complex mixtures of
heavy and light
fractions) and particulates (sand, minerals etc.). While the majority of
hydrocarbons are
removed from this produced water and the majority of water is recycled for
steam production a
certain volume of produced water is raw water that is contaminated with a
combination of salts,
hydrocarbons and particulates. These facilities use one to many dozen steam
generators, such
as Once-Though Steam Generators and Heat-Recovery Steam Generators (HRSG).
These
generators typically have power outputs ranging from 3MW to 250MW. The by-
product of the
combustion heat utilized by these systems is a low grade heat that is no
longer economically
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usable by current heat exchange technology and which is vented to atmosphere
using large
chimney stacks. As one example a 50MW Steam Generator may have a 2-3 meter
diameter
flue stack, downstream of an economizer, which releases flue gas to atmosphere
with an
approximate temperature of 150 C-200 C. Drawbacks of prior art systems are an
inability to
utilize this low grade heat. Drawbacks to other prior art systems is they have
to bring the heat
from 30+ meters up a flue stack to ground level for processing, and by doing
so lose more heat.
These latter systems although described as compact are not light nor compact
enough satellite
installation at the top of the flue stack. Further, even if prior art systems
were light and compact,
they are prone scale buildup within their systems, requiring ground level
operator access for
ongoing cleaning and maintenance, which results in ongoing, undesirable
operational expense.
[0016] Similarly, at gas production facilities, gas plants or remote
compressor stations,
where produced gas is recovered at surface and compressed for delivery to
pipelines, connate
water is recovered with the gas which is substantially raw water. As noted
above, this raw water
is also a varying mixture of salts, hydrocarbons and particulates and can be
produced in
volumes of up to several hundred cubic meters of water per day, per single
site. There are a
variety of engine types and sizes utilized in oilfield operations. These
generators and associated
engines can vary greatly, but typically range in size and power ratings from
about 500kW at a
drilling rig to about 2500kW at gas production and compression facilities.
Such engines are
typically used to generate power and to drive gas compression systems at gas
production
facilities. Generally, the temperate of the exhaust gas is about 300-700 C,
depending on engine
type and engine load.
[0017] At a drilling rig, engines are typically portable systems that are
positioned
adjacent to drilling equipment whereas at a gas production facility, the
engines and
compressors are typically permanent or semi-permanent installations. At each
operation, each
engine is connected to muffler systems to manage noise associated with the
engine. Typically,
large muffler systems for example paired to a 2,000kW engine-generator set are
installed in a
vertical orientation adjacent to or above the engine which smaller engines for
example 500-
1200kW may have a horizontal orientation. Similarly, the temperature of the
exhaust gas is
about 300-700 C.
[0018] Such engines have variable performance characteristics including
varying
exhaust pressures, exhaust flow rates/speeds, exhaust temperatures and
backpressure
tolerances. Table 1 show typical performance characteristics for different
engine sizes.
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Table 1-Representative Engine Performance Characteristics (not muffled)
Engine Exhaust Exhaust Pipe Exhaust Flow Exhaust Push
Power Temperature Diameter Rate Backpressure Power
Rating (bhp) ( C) (Typical) @100% Max (max) WC (kW)
@100% Max Load inches (kPa)
Load
600-850 550 5-8" 112 m3/min 40" WC 19
(10 kPa)
1000-1500 400-450 10-16" 221 m3/min 27"WC 25
(7 kPa)
2300-2500 450-500 18-22" 451 m3/min 10-14" WC 19-27
(2.5-3.5 kPa)
[0019]
As can be seen from Table 1, in many cases as an engine becomes larger it is
generally less able to tolerate significant backpressure. As a result, there
has been a need for
raw water vaporization systems that can be adapted to different engines
without adversely
affecting the performance of that engine to conduct its primary function at a
work site.
[0020]
More specifically, there has been a need for an ICE Exhaust gas delivery
system
that provides any one of or a combination of static, control actuated, flow
actuated or pressure
actuated control systems that directs and allows ICE exhaust to be effectively
used to at least
partially shear, boil and/or vaporize raw water while ensuring the maximum
backpressure limits
as seen by the engine are not exceeded. As can be seen in Table 1, the push
pressure of an
ICE is significant when utilized for the purpose of shearing, vaporizing and
as discussed below
can also be used as input pressure for an induced cyclone for demisting
entrained water
droplets from the exhaust gas. Other various demisting methods may also be
employed,
including impingement based demisters as are known to those with skill in the
art.
[0021]
Furthermore, to further enhance the scope of using different heat sources,
there
has been a need for low pressure combustion gas delivery systems that, as
needed, can be
enhanced by additional pressure inducing devices (e.g. blowers).
[0022]
Further still, in order to reduce the capital costs associated with
implementing
vaporizer systems, there has been a need for compact and relatively light
weight vaporizer
systems that can be manufactured from plastics whilst operating in hot
environments. In
addition, to reduce manufacturing costs, such systems can also provide
advantages for the
installation of vaporizing systems on existing equipment, such as tall chimney
stacks. Further, a
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vaporization and demisting system with non-stick inner surfaces minimizes
scale buildup within
the system thereby reducing the need for maintenance, as with prior art
systems, and allows for
remote installation on tall exhaust stack structures.
[0023] Further still, in order to improve the efficiency of vaporization,
there has been a
need for improved combustion gas velocity modifier, stabilizer, manipulator or
generator
systems, referred to collectively as an "air knife" system designed to utilize
the waste pressure
within ICE combustion gas for shearing and vaporizing raw water by
mixing/interfacing exhaust
gases with raw water. Alternatively, in embodiments where there little or no
waste pressure is
available, an air knife system may be used in conjunction with a blower,
rotor, fan or the like in
order to assist with shearing and vaporization of raw water. In various other
embodiments an air
knife system can be used in conjunction with a demisting cyclone system.
[0024] Further still, there is a need to remove VOCs (Volatile Organic
Compounds) from
produced water.
[0025] Further still, there is a need to remove barium from produced
water.
[0026] Further still, there has been a need for vaporizing systems that
in addition to
vaporizing raw water are effective as muffler systems for large ICE's. That
is, there has been a
need for an inline, muffling, self-washing vaporizer that can be placed
remotely adjacent to,
upstream from or downstream from an existing muffler is desirable.
[0027] Further still, there has been a need for vaporizing and
concentrating systems that
are effective in reducing the build-up of scale within the systems that
require maintenance to
remove the scale. There is a particular need for such systems where the raw
water being
vaporized is continuing to be enriched in contaminants that due to the
enrichment are
particularly susceptible to precipitation within the system. In particular,
there has been a need
for vaporizing systems that are effectively and efficiently being continually
cleaned during
operation.
[0028] Furthermore, there has also been a need for systems that can
reduce the amount
of exhaust contaminants that may be released to the atmosphere while at the
same time
reducing the total volumes of contaminated waste water that require shipping
and/or removal
from an industrial waste generation site.
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[0029] Additionally, there is a need for a system for the management,
reporting,
distribution and/or controlling of many distributed systems within a grid of
systems that allows
for feedback to a central processing system wherein processing rates, raw
water storage,
condensed water storage, combustion gas temperature and pressure, run time,
processing
volumes and the like are collected and managed.
[0030] Furthermore, there has also been a need for systems that
effectively manage
concentrated salt solutions, either by drying salts so there is substantially
zero liquid
concentrate discharge or a system that can concentrate a salt solution to just
under its
maximum saturation point so the salts stay in solutions and can be disposed of
by deep well
injection.
[0031] Further still, there has also been a need for systems that can be
readily retrofit to
existing oilfield equipment with minimal capital cost, operating cost,
footprint, or operational
impact.
[0032] Examples of past systems include US 8,066,844 which describes a
concentrator
designed to operate utilizing waste "heat" from land fill gas in which the
system is under
negative pressure. Applying vacuum pressure on the system is taught due to
lack of positive
push pressure from the land fill gas heat source. The prior art discusses an
alternative use of
"heat" only from an engine exhaust system as a preheating method, but does not
contemplate
the use of the positive pressure resource within engine exhaust. In operation,
the effect of the
negative pressure applied to the exit of the prior art system would at least
in part neutralize the
effect of positive engine exhaust pressure. Additionally, as a result of the
focus of US '844 on
land fill gas waste heat utilization with no or little associated positive
pressure, there is no
teaching of using the positive pressure within engine exhaust gas to at least
partially atomize,
shear or break droplets as a means for interfacial surface area generation.
Importantly, in the
US '844 system, negative pressure at the exit of the system allows a venturi
effect upstream of
the suction as a means of creating raw water interfacial surface area
generation. In other
embodiments the US '844 system describes using a blower upstream of the
vaporizer section of
the system to provide required push pressure needed for the venturi water
mixing system.
Regarding the latter, a drawback to this system is that new energy input is
required, at a cost, in
order to shear and mix water with a heat source. Substantial drawbacks to
various US '844
systems are the described requirement for cleaning and maintenance of scale
and salt deposits
due to many wet/dry surfaces within the system. These drawbacks are also
associated with a
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cyclonic demister whose inlet is tangential rather than concentric in that
within the cyclone there
are substantial dry surfaces that buildup scale, salts, etc. and require much
maintenance and
cleaning.
[0033] Examples of past systems also include those described in US Patent
7,722,739,
US Patent 5,259,931, US Patent Publication 2009/0199972, US Patent Publication
2009/0294074, US Patent 5,770,019, US Patent 5,573,895, US Patent 7,513,972,
US Patent
2,101,112, and US Patent 6,200,428.
[0034] Applicant's Canadian patent 2,751,895 (and related co-pending
applications
based on PCT/CA2010/001440) also describes improved raw water vaporization
systems and
are incorporated herein by reference in their entirety.
SUMMARY OF THE INVENTION
[0035] According to a first aspect, there is provided a raw water
vaporization system
(RVVVS) comprising:
a vaporization chamber having:
raw water and gas inlets configured inject water and gas to within the
vaporization chamber to effect raw water vaporization; and
an outlet at the bottom of the vaporization chamber;
a concentrator tank positioned in a plane below the vaporization chamber such
that
material exiting the vaporization chamber via the vaporization chamber outlet
impinges with
liquid in the concentrator tank; and
a raw water channel configured to inject raw water from the concentrator tank
into the
vaporization chamber via at least one of the raw water inlets.
[0036] The gas inlet may be configured to direct gas flow through the
vaporization
chamber and directly into liquid contained in the concentrator tank.
[0037] The concentrator tank may have gas outlets arranged in the top
surface of the
concentrator so that gas entering the concentrator tank from the vaporization
outlet must
change direction to exit the concentrator tank gas outlets.
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[0038] The concentrator tank may be tapered at the bottom.
[0039] The concentrator tank may comprise a recirculation loop for
recirculating the
liquid within the concentrator tank.
[0040] The concentrator tank may comprise an agitator.
[0041] A vaporization chamber gas inlet may be configured to manipulate
the gas flow,
direction and/or speed enabling control of the gas at the outflow orifice in
relation to the inlet
orifice of the adaptor, resulting in the improved or optimal use the gas heat,
pressure, vector
and/or velocity. For example, by constricting the gas flow the speed of the
gas flow may be
increased.
[0042] A said vaporization chamber gas inlet may be an air knife.
[0043] The gas may be one or more of hot gas; an exhaust gas; and a
combustion gas.
[0044] The gas source may be one or more of: an engine exhaust; an ICE
exhaust; a
turbine engine exhaust; and a combustion gas from a flame.
[0045] At least a portion of the RVVVS may be coated with PTFE.
[0046] The gas inlet may be configured to introduce hot gas into the top
of the
vaporization chamber.
[0047] The air knife may be configured to induce a hot gas speed within
the chamber of:
between 40m/s and 150m/s when water inlet pressure is 2-100psi or when fine to
very
course droplet sizes are introduced into the gas velocity; or
between 1m/s and 60m/s when water inlet pressure is 10-500p5i or when fog
droplets to
course droplet sizes are introduced into the gas velocity.
[0048] The apparatus may comprise a gas conduit configured to deliver gas
to the gas
inlet wherein the gas conduit comprises a gas piping configuration, including
a "Y" or "Tee"
shaped pipe, and the gas conduit includes:
a release valve, the release valve configured when open to allow gas from the
gas
source to be vented into the atmosphere either directly or through an adjacent
muffler and when
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released allows the valve to close or partially close and to direct at least a
portion of gas
towards the air knife adaptor; and
a control valve configured when open to allow gas to be directed through the
air knife
and when closed to prevent gas being directed through the air knife.
[0049] The RVVVS may be configures such that when the release valve is
open air is
drawn counterflow from the air knife or gas inlet.
[0050] The RVVVS may comprise a demister configured to receive gas and
entrained
liquid from the headspace within the concentrator tank and separate the gas
from the entrained
liquid.
[0051] The RVVVS may comprise a rotational-flow inducer to induce
rotational motion to
the gas and entrained liquid to separate the gas and entrained liquid using
centrifugal forces.
[0052] The RVVVS may comprise multiple vaporization chambers feeding into
a single
concentrator tank.
[0053] A pump bringing new raw water into the concentrator tank may be
configured to
operate a flow corresponding to the rate of vaporization in the vaporization
chamber to thereby
allow the RVVVS to operate in a continuous mode. A controller may be
configured to control the
pump rate of the pump pumping fresh raw water into the system to maintain a
continuous rate of
operation.
[0054] The RVVVS may comprise a barium precipitating reagent injector
configured to
inject a reagent (e.g. a soluble sulfate such as Na2SO4) into the raw water to
precipitate
dissolved barium salts.
[0055] According to a further aspect of the present disclosure, there is
provided a raw
water vaporization system (RVVVS) comprising:
a vaporization chamber having:
raw water and gas inlets configured inject water and gas to within the
vaporization chamber to effect raw water vaporization and
an outlet to allow gas and liquid out of the vaporization chamber; and
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multiple demisters, each demister configured to receive a portion of the gas
from the
vaporization chamber and to remove high density material entrained in the
received portion of
the gas.
[0056] The high density material entrained in the gas may comprise liquid
water. The
high density material entrained in the gas may comprise solids.
[0057] The outlet of the vaporisation chamber may be connected to each of
the multiple
demisters by a channel.
[0058] The outlet of the vaporisation chamber may be connected to each of
the multiple
demisters by a channel, the channel being formed by the headspace of a
concentrator tank.
[0059] The outlet of the vaporisation chamber may be connected directly to
each of the
multiple demisters.
[0060] Each demister may comprise a circularly symmetric body with a
rotational-flow
inducer at one end of the demister body; a gas outlet at the other end of the
demister body; and
a second outlet (e.g. for high density materials such as liquid water and/or
entrained solid
particulates) at the bottom of the demister.
[0061] The liquid outlet may comprise a channel which connects the
demister with a
position below the liquid level of a concentrator tank.
[0062] According to a further aspect of the present disclosure, there is
provided a
method of vaporising raw water comprising:
injecting raw water and gas such that they mix together in a mixing zone to
effect raw
water vaporization, wherein the mixing occurs directly above an open
concentrator tank
positioned such that high density materials from the mixing zone will be
directed to impinge with
liquid in the concentrator tank;
and wherein the raw water for injection into the mixing zone is pumped from
the
concentrator tank.
[0063] According to a further aspect of the present disclosure, there is
provided a
method of vaporising raw water comprising:
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injecting raw water and gas such that they mix together in a mixing zone to
effect raw
water vaporization;
directing gas flow from the mixing zone to multiple demisters, each demister
configured
to receive a portion of the gas from the mixing zone; and
removing high density material entrained in the received portion of the gas
using the
demisters.
[0064] It will be appreciated that vaporization may encompass one or more
of:
vaporization, evaporation and boiling.
[0065] In various embodiments, the gas inlet has a round, oval, square,
irregular,
rectangular, duckbill or helical configuration and may constrict exhaust flow
or expand exhaust
flow.
[0066] The gas inlet may comprise a diverter within or adjacent the
outflow orifice. The
diverter can be manually or automatically adjustable based on gas pressures or
PLC control
increase or decrease exhaust gas velocity within the outflow orifice.
[0067] The gas inlet may comprise openings to enable introduction of
additional gas to
the air knife upstream of the outflow orifice.
[0068] A diversion valve may be operatively connected to the engine
exhaust connector
for diverting exhaust under pressure to or from the engine exhaust source to
the exhaust
conduit and/or the air knife.
[0069] In one embodiment, the exhaust connector is adapted for any one of
or a
combination of constricting, expanding, diverting and focusing engine exhaust
within the
shearing chamber as a means to utilize the engine exhaust pressure and
velocity to effect raw
water shearing.
[0070] In other embodiments, the axis of the demisters may be inclined
away from the
vertical (e.g. by between 5 and 30 ).
[0071] The vaporization chamber may be a shearing chamber where water
droplets are
sheared to a smaller size through interaction with the moving gas flow.
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[0072] In one embodiment, the RVVVS includes a controller operatively
connected to i) a
water pump operatively connected to a raw water conduit, the water pump for
pumping raw
water to the raw water influx system and ii) at least one thermocouple
operatively connected
downstream of the shearing chamber for measuring a first temperature of gases
exiting the
RVVVS and wherein the controller increases flow of raw water to the shearing
chamber if the
first temperature is above a first threshold and decreases the flow of raw
water to the shearing
chamber if the first temperature is below a second threshold. In one
embodiment, the first
threshold is 100 C and the second threshold is 50 C. In other embodiments the
first threshold is
between 90 C and 120 C and the second threshold is between 65 C and 100 C. In
some
embodiments the first threshold is between 90 C and 120 C and the second
threshold is
between 65 C and 90 C.
[0073] In one embodiment, the shearing chamber is adapted to receive
engine exhaust
from an associated engine at substantially the same pressure and temperature
of the engine
exhaust exiting the associated engine.
[0074] In one embodiment, at least one surface within a combination, 2-in-
1 shearing
chamber and demister imparts a centrifugal force to the exhaust gas and water
vapor to enable
entrained water droplets to impinge and coalesce on inner surfaces of the 2-in-
1 vessel to effect
demisting of exhaust gas and water vapor prior to release to the atmosphere.
[0075] In another aspect, the invention provides a centrifugal demisting
apparatus
having: a frustoconical drum having a first smaller outer diameter at an inlet
end and a larger
outer diameter at an outlet end, the frustoconcial drum having an inner
surface for imparting
centrifugal forces on a mixture of exhaust gas, water vapor and entrained
water droplets as the
mixture transits from the inlet end to the outlet end under pressure to effect
impact of entrained
water droplets on the inner surfaces and removal of the entrained water
droplets from the
mixture.
[0076] In a further aspect, the invention provides a centrifugal
demisting apparatus
having: a chamber having an inlet end and an outlet end and having at least
one inner surface
within the chamber, at least one surface for imparting centrifugal forces on a
mixture of exhaust
gas, water vapor and entrained water droplets as the mixture transits from the
inlet end to the
outlet end to effect impact of entrained water droplets on the inner surfaces
and removal of the
entrained water droplets from the mixture, the inlet and the outlets being
concentrically aligned.
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[0077] In yet another aspect, the invention provides a raw water
vaporization system
(RVVVS) kit. The kit may comprise: an adaptor for connecting an engine exhaust
source from an
associated engine, the adaptor having an exhaust conduit having an engine
exhaust connector
for connecting the conduit to engine exhaust piping; an air knife at an
outflow end having an
outflow orifice adapted for connection to a shearing chamber; the shearing
chamber having a
raw water influx system for operative connection to an engine exhaust pressure
and
temperature source to enable rapid interaction between input raw water and
engine exhaust for
i) increasing interfacial surface area between the input raw water and the
engine exhaust gas
and ii) rapid heat transfer between the input raw water and the engine exhaust
to effect
vaporization of water from the raw water and the concentration of raw water
contaminants when
a engine exhaust source is conveying pressurized engine exhaust into the
shearing chamber;
wherein the adaptor and shearing chamber are independent apparatus operatively
connectable
to one another.
[0078] In various embodiments more than one water nozzle or water
injection device
may be used. In these embodiments various water injection systems may be under
various
pressures and injected at the same or various angles in relation to the flow
of either the exhaust
gas or the other water sources. Various water sources may be raw water, raw
water concentrate
and/or clean water, any of which may be preheated.
[0079] In one embodiment, the invention includes the step of monitoring
the back
pressure on the engine and controlling at least one diversion valve
operatively connected
between the shearing chamber and the engine exhaust source to maintain the
back pressure
below a threshold. In various embodiments depending on the size of the ICE,
the backpressure
threshold may be a maximum of 10"WC, 14"WC, 27"WC or 40"WC. Any valve
configured to the
exhaust delivery system may vent exhaust to atmosphere, to another vaporizer
or to a muffler.
[0080] In other embodiments, the invention includes a counter-weighted
valve
adjustable or configurable to vent excess exhaust pressure that would exceed
an engine
specific upper threshold, from the ICE exhaust delivery system to allow
maximum delivered
exhaust flow and pressure to a vaporization chamber. The counter weighted
valve may be
decoupled from a main valve controlled by a PLC or may be a separate valve
adding redundant
safety to the ICE exhaust delivery system. The counter-weighted valve(s) may
vent exhaust to
atmosphere, to another vaporizer or to a muffler.
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[0081] In one embodiment, the method includes the step of measuring the
temperature
and/or pressure of any combustion gas prior to the shearing chamber and based
on the
combustion gas temperature and/or pressure adjusting the flow rate of water,
the combustion
gas volume, gas velocity and/or gas pressure delivered to a shearing chamber
or an array of
shearing chambers configured to one or more combustion gas sources.
[0082] In various embodiments, the method includes the step of measuring
the
temperature of the exhaust gas after exiting the shearing chamber and based on
the
temperature of the exhaust gas after exiting the shearing chamber adjusting
the flow rate of the
water or exhaust gas volume, gas velocity and/or gas pressure to the shearing
chamber to
maintain the temperature of the exhaust gas after exiting the shearing chamber
with a range of
temperature.
[0083] In other embodiments, the flow rate of raw water or combustion gas
volume, gas
velocity and/or gas pressure into the shearing chamber is controlled to
maintain the temperature
of exhaust gas exiting the shearing chamber between 50 and 100 C. In other
embodiments the
first threshold is between 65 C and 90 C and the second threshold is between
90 C and 120 C.
[0084] In another embodiment, the engine exhaust is introduced to the
shearing
chamber under pressure and flow conditions substantially equivalent to the
pressure and flow of
exhaust gas exiting the associated engine or combustion gas source.
[0085] In another embodiment, a combustion gas exhaust is introduced to
the shearing
chamber under pressure and flow conditions greater than the pressure and flow
conditions of
the exhaust gas exiting the combustion gas source.
[0086] In another aspect, the invention provides a method for distributed
management of
raw water and combustion gas as a means of maximizing resource utilization
comprising the
steps of: a) establishing at least one physical or virtual hub to receive raw
water or other
resource or waste inputs from members, member sites or member sub-sites within
a network of
raw water generators, resource consumers or waste collectors; b) analyzing
location data of the
members, member sites or member sub-sites within the network for utilization
availability; and c)
distributing or redistributing the raw water, condensed clean water, brine
concentrate and/or
salts to the members, member sites or member sub-sites in a prioritized manner
as a means to
enable maximum benefit, efficiencies, resource consumption reductions and/or
use to those
within the network.
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[0087] In one embodiment, at least one central hub can communicate
utilization data to
members within a network, group or sub-group.
[0088] In another aspect, the invention provides a method of controlling
a raw water
vaporization system (RVVVS) having an engine exhaust source operatively
connected to a
shearing chamber used to effect vaporization of raw water, the method
comprising the steps of:
a) monitoring backpressure on the engine exhaust and b) increasing or
decreasing raw water
flow to the shearing chamber to maintain the backpressure on the engine
exhaust below a
threshold.
[0089] In other aspects, the invention provides a method of controlling a
raw water
vaporization system (RVVVS) having an combustion gas source operatively
connected to a
shearing chamber, the method comprising the steps of: a) monitoring at least
one combustion
gas pressure upstream or downstream of a shearing chamber or demisting device,
b)
monitoring at least one temperature upstream or downstream of a shearing
chamber or
demisting device and c) adjusting raw water inlet pressure against at least
one water distribution
nozzle to enable distribution of a desired average raw water droplet size as
the raw water is
distributed within the shearing chamber to maintain the at least one
temperature within a
temperature range. In various embodiments the desired temperature exiting a
demisting device
is above 65 C and less than 120 C, preferably between 90-110 C. Other
embodiments the
desired temperature exiting a demisting device may be less than 90 C.
[0090] In another aspect, the invention provides a method of assembling a
raw water
vaporization system (RVVVS) at a remote site having an engine and engine
exhaust piping, the
method comprising the steps of: a) configuring an adaptor as defined above to
the exhaust
source b) attaching a vaporization chamber as defined below the adaptor; and
c) attaching a
raw water supply to the vaporization chamber.
[0091] The chamber and directed outflow orifice of the hot gas conduit may be
substantially
circularly symmetric.
[0092] The deflector plate may be configured to allow at least a portion of
the raw water flow to
drain from the vaporization chamber away from the vessel and/or into a
demisting device.
[0093] The deflector plate may be configured to be at the base of the
vaporization chamber and
the hot gas outflow orifice is configured to introduce hot gas into the top of
the chamber.
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[0094] The chamber may be a cylinder. The chamber may be 18-24" high and 24"
in diameter)
[0095] The outflow orifice may be formed from a hollow cone.
[0096] The raw water/gas mixture within the chamber may be in the form of a
toroid.
[0097] The RVVVS may comprise a rotational-flow inducer positioned below the
deflector to
induce an axially rotational motion to raw water draining from the chamber.
The rotational-flow
inducer may comprise a stator with angled blades. The rotational-flow inducer
may comprise an
actively or passively driven rotor.
[0098] According to a further aspect, there is provided a raw water
vaporization system (RVVVS)
comprising:
a shearing chamber;
a raw water nozzle configured to introduce raw water into the chamber;
a hot gas conduit having an air knife at an outflow end of the hot gas
conduit, the air knife
configured to direct at least a portion of the engine exhaust within the
exhaust conduit into the
raw water flow inside the shearing chamber to effect raw water shearing.
[0099] The air knife may be configured to induce a combustion gas speed within
the chamber of
between 2-20m/s, 10-30m/s, 20-40m/s and other ranges 30-100m/s.
[0100] The air knife may comprise a hollow cone or a full cone
[0101] The air knife may be comprised of a cylindrical or frustoconical shape.
[0102] The RVVVS may comprise a control system configured to control the air
knife to maintain
gas flow velocity from the air knife within a threshold range.
[0103] An ICE may have a power in the range of one or more of: 600-850bhp;
850-
1000bhp; 1000-1500bhp; 1500-2300bhp; and 2300-2500bhp (or larger).
[0104] The air knife may be considered to be a pressurized air channel
containing a
series of holes or continuous slots through which pressurized air exits in a
laminar flow pattern.
The air knife may be straight or curved. The air knife may extend along an
axis (e.g. straight or
curved axis) and have a restricted lateral dimension. The exit velocity of the
pressurized air from
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the air knife may be one or more of: between 40-50m/s; between 50-70m/s;
between 70-
100m/s; and greater than 100m/s; between 2-20m/s, between 10-30m/s, between 20-
40m/s and
between 30-100m/s. Other ranges may also be used.
[0105] The air knife may have openings to enable introduction of
additional gas to the air
knife upstream of the outflow orifice. The additional gas may comprise ambient
air (e.g. to
increase the water carrying capacity of the gas) or hot gas from an additional
hot gas source.
[0106] The raw water nozzle may be configured to introduce raw water into
the shearing
chamber with one or more of: dry fog (<10 pm Volume Mean Diameter ¨ VMD); fine
mist (10-
100 pm VMD); a fine droplet size (100-200pm VMD); a medium droplet size (200-
350pm VMD);
a coarse droplet size (350-600pm VMD); a very coarse droplet size (600-900pm
VMD); an
extremely coarse droplet size (900-2000pm VMD); and an ultra coarse droplet
size (>2000pm
VMD). In each case, the raw water flow, angle, direction and force should
considered in
combination with width and velocity of the gas stream its being injected into.
It is desirable the
chosen design is sufficient to permit raw water to penetrate the gas flow
stream to at least 20%
of the width/length of the gas flow stream, but preferably 30-100% penetration
is preferred. In
other words, it is desirable that the impact force between the gas and water
streams is sufficient
for the water to penetrate the gas stream to enable mixing and, hence,
shearing. This improves
system efficiency but also enables proper sizing of the chamber, washing of
the chamber and
the minimization or elimination of any dry spots.
[0107] Generally, the higher the raw water pump pressure acting as
shearing force on a
water nozzle (for a given water flow rate), the smaller the average droplet
size. The smaller the
average droplet size, the greater the surface area of the droplet in relation
to the mass of the
droplet. The greater the surface area in relation to droplet mass, the faster
thermal energy can
transfer from gas into the droplet enabling vaporization of a portion of the
droplet. In an example
embodiment if there is sufficient waste pressure in engine exhaust to perform
the shearing of
the raw water so the thermal transfer of combustion gas heat is enabled within
a short
timeframe and geometric space, then there would be no need to provide input
energy to a raw
water pump or provide energy input to a blower. In this case the push pressure
of the engine
mitigates or subsidizes the need for energy inputs. In other example
embodiments where there
is little or no pressure within a combustion gas source, the overall system
can be designed to
minimize supplementary energy inputs by balancing how input energy is used for
raw water
shearing and demisting of water entrainment. For example, an operator may
choose to
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pressurize the raw water with a raw water pump to enable sufficient shearing
of raw water thus
minimizing the need for gas pressure to do the shearing. In this way input
energy required for a
blower is minimized and relegated primarily to drive a demisting cyclone. In
other embodiments
where there is at least partial pressure from a combustion gas source, such as
downstream
from a muffler, the system can be balanced to minimize energy input needed for
blower
pressure by at least partially utilizing waste pressure within the combustion
gas.
[0108] As such, in some embodiments, the shear chamber may be considered
to be a
vaporization chamber in which a hot gas flow impinges on a raw water flow in
order to reduce
the size of the raw water droplets. A vaporization chamber may be considered
to be a
substantially enclosed vessel (with inlets and outlets for liquid and gas) in
which heat is
transferred from a hot gas to raw water to effect vaporization through
vaporization and/or
boiling.
[0109] After interaction between the raw water from the nozzle and the hot
gas, the
droplet size may be smaller than the droplets ejected from the nozzle.
[0110] The pressure applied to the raw water nozzle may be 30p5i or
greater (or 40p5i
or greater) for medium to course droplets. Dry fog may be induced by 100-500
psi pump
pressure. The pressure may be 10-30 psi for medium to course droplets or under
20 psi for
course to ultra-course droplets. As can be understood, various nozzle shapes
and pressures
can result in varying droplets sizes and the described sizes are not intended
to be limiting, but
used as examples.
[0111] The shearing chamber may be cylindrically shaped.
[0112] The width (e.g. diameter) of the chamber is typically less than 36
inches (e.g.
around 2-4 feet). The height of the chamber may be between 12-36 inches (e.g.
between 1.5
and 2 feet). Larger systems can vary in size and proportion, although it is
desirable to limit the
chambers inner surface area as much as possible to promote washing and limit
dry surfaces
within the shearing chamber.
[0113] The shearing chamber may comprise a raw water influx system
operatively
positioned adjacent the gas connector to enable rapid interaction between
input raw water and
gas for washing the interior surfaces of the vaporization chamber.
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[0114] The cross-sectional width of the air knife stream may be configured
to permit raw
water being sprayed or delivered to it, under various pressure and with
various average droplet
sizes, to penetrate from 20%-100% of the entire width of the gas stream, or
cross the gas
stream. This may reduce or minimize the volume of space within the
vaporization chamber
needed for thermal transfer and so facilitates the washing effect within the
vaporization
chamber.
[0115] Regarding monitoring pressure of gases being delivered to the
shearing
chamber, when using an ICE, the controller helps ensure no overpressure or
temperature is
applied to the engine while increasing or maximizing heat and pressure used
for optimal water
vaporization and system washing. The pressure control system may be used to
control the
valves in the exhaust diversion system to ensure a desired pressure range is
maintained.
[0116] The control system may comprise a processor and memory. The memory
may
store computer program code. The processor may comprise, for example, a
central processing
unit, a microprocessor, an application-specific integrated circuit or ASIC or
a multicore
processor. The memory may comprise, for example, flash memory, a hard-drive,
volatile
memory. The computer program may be stored on a non-transitory medium such as
a CD.
[0117] The system may comprise a release valve upstream from the shearing
or
vaporization chamber to vent air into the atmosphere (e.g. directly or via a
muffler). The release
valve may be configured to open to various degrees in response to pressure
signal from
backpressure at any point in the exhaust circuit. This may be facilitated by
enabling any one or
all of the following to act upon the valve to open (or partially open) it:
= a counter-weighed stand alone, integrated or decoupled valve for non-
automated
venting control
= a direct air line from anywhere in the exhaust circuit,
= pressure transmitter signalling a PLC (programmable logic controller) to
activate an
electric, pneumatic, hydraulic, or other means.
[0118] The release valve may comprise a counterweighted vent. The counter-
weighed
vent valve may be decoupled for passive pressure control. The amount of
counterweight or
other bias may be tailored to the hot gas source and, in particular, to the
tolerance the hot gas
source has to overpressure. It will be appreciated that the release valve may
open to allow gas
to allow a portion of gas to vent without passing through the vaporization
chamber whilst a
'control valve' also stays open allowing another portion of gas to travel
through the vaporization
chamber. If the pressure is even higher, the control valve may be closed to
divert all exhaust
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gasses away from the vaporization chamber and into the atmosphere, either
directly or through
a muffler.
[0119] This configuration may help increase or maximise the use of the
exhaust
pressure and heat by venting as little as possible away from the air knife.
For example, the
weighted release valve can have weights associated with a balanced internal
valve designed to
only vent the minimal portion of over pressure gas. Gas delivery can be
further optimized to the
air knife when assisted with direct air pressure signal to an electric device
that is configured to
open the release valve incrementally due to predesignated pressures within the
exhaust circuit
in order to maintain a maximum pressure within the exhaust circuit. For
example if the engine in
use is a 2500bph with a maximum allowable engine back pressure of 14"WC, then
by a signal
from PLC (programmable logic controller) or direct air pressure from an
airline connected to the
exhaust pipe closer to the engine and the other end to a small actuator, the
actuator can be
configured to assist the release valve with incremental opening to allow
staged and controlled
venting. This may help reduce or minimize the amount of exhaust being vented
away from the
air knife when the exhaust circuit pressure begins to climb, primarily due to
engine load
increases. The release valve, for placement inside an exhaust pipe system
(e.g. to vent to a
muffler) or at the exit of an exhaust pipe (e.g. to vent to atmosphere), may
have the following
traits or attributes:
(1) ensure low friction on a valve rod or other rotatable fixture that can
withstand:
high heat, rapid heating and cooling without warping from thermal shock,
combustion
gas particulate matter;
(2) ensure the placement of the valve within the exhaust pipe and on the
bearing rod
or similar fixture is optimized to allow a counter weight to open it with
pressure and
(3) configured with a counterweight or other biasing mechanism (e.g. spring),
the
bias being adjustable to enable a maximum pressure delivery to the air knife
without
creating excessive backpressure to the gas source (e.g. chosen engine type per
manufacture specification).
[0120] These various exhaust delivery systems can be used with an air
knife with a fixed
cross-sectional orifice or with an air knife configured to actively or
passively adjust the gas
velocity at the outflow orifice. In other various embodiments or combinations
they can be
configured to allow a fixed gas volume through an air knife (by venting excess
away from the air
knife), a fixed pressure within the exhaust system (resulting in variable gas
flow through the air
knife) or modulated actively or passively to enable other desired
combinations.
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[0121] The RVVVS may have a concentric design, and a round water nozzle
(hollow or
full cone). The water nozzle(s) may self-clean via pneumatic connection or
periodic pulsing with
air. In addition, portions or the system may be coated with PTFE or other non-
stick coatings to
help reduce scaling (formation of solid precipitate or other solids on the
surfaces of the system).
[0122] Regarding controlling or adjusting the air knife, the air knife can
be controlled
actively or passively. Active control may use a control system with an
actuator configured to
adjust the air knife based on one or more of user input or sensed variables
such as temperature
or pressure. Passive control may be implemented by the air knife being spring
loaded (or
manually set in increments) to manage itself based on backpressure. That is,
the back pressure
itself may act on the spring to open or close off (or otherwise modify) the
cross-sectional
opening of the air knife exit orifice. This modulating of cross-sectional
orifice in response to gas
flow fluctuations and pressure, permits the velocity of the gas being
delivered to the vaporization
chamber to remain within a narrower band resulting in more predictable
gas/water mixing
behaviour.
[0123] A hollow cone is a geometric shape formed between two complete
cones
arranged coaxially with a displacement along the axis. It may describe the
shape of fluid flow
(liquid or gas) in which the fluid flows from a point within an angle range
around a particular
cone axis. It may also describe a gas conduit formed by placing a solid cone
obstruction within a
channel.
[0124] Regarding the stators described herein, the stator may comprise
angled vanes
with one or multiple angles surfaces, various channelled configurations or
helical configurations
to induce rotational motion of gas when pushed or pulled past the stator
surfaces.
[0125] Regarding the pressure of the gas being supplied to the
vaporization chamber,
the gas may be introduced to the shearing chamber under pressure and flow
conditions
substantially equivalent to the pressure and flow of gas exiting the
associated gas source. The
pressure may be supplied by the gas source itself (e.g. an engine). In other
embodiments, the
pressure supplied by the gas source may be supplemented by active elements
such as a blower
for induction or suction. This may be advantageous in embodiments where the
hot gas source
does not provide pressure (e.g. flares or flames).
[0126] In some embodiments there may be no air knife and so gas velocity
may be low.
In such cases, the water may be mechanically sheared to reduce the droplet
size. Mechanical
shearing may be effected using higher water pump pressure or by impinging the
water flow on a
solid surface or through a mesh. In this case where water is atomized and
sheared by the water
pump, the gas may be cooled by vaporization causing cyclonic demisting takes
place.
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[0127] Some embodiments may use a blower to induce gas flow through the
vaporization chamber primarily to reduce the pressure within the demisting
chamber to induce
cyclonic separation.
BRIEF DESCRIPTION OF THE DRAWINGS
[0128] Various objects, features and advantages of the invention will be
apparent from
the following description of particular embodiments of the invention, as
illustrated in the
accompanying drawings. The drawings are not necessarily to scale, emphasis
instead being
placed upon illustrating the principles of various embodiments of the
invention. Similar reference
numerals indicate similar components.
Figures 1A and 1B are perspective and plan views respectively of multiple
RVVVS's
configured to a compressor facility in accordance with one embodiment of the
invention.
Figure 1C is a perspective of a RVVVS system configured to a gas production
facility in
accordance with various embodiments of the invention.
Figure 2 is a schematic view of the sub-components of a RVVVS in accordance
with one
embodiment of the invention.
Figures 3A-3C are schematic vertical cross sectional views of a raw water
vaporization
system in accordance with one embodiment of the invention.
Figures 3D is a front perspective view of the raw water vaporization system of
Figure
3A.
Figures 3E-3F are front and end views of the of the raw water vaporization
system of
Figure 3A.
Figures 3G-3I are vertical cut-through views of the of a raw water
vaporization system of
Figure 3A.
Figures 3J-3M are a series of horizontal cut-through views of the of a raw
water
vaporization system of Figure 3A.
Figures 4A-4F are schematic diagrams of various hot gas delivery systems and
various
exhaust/water contact configurations in accordance with various embodiments of
the
invention.
Figure 5 is a schematic vertical cross sectional view of a raw water
vaporization system
in accordance with one embodiment of the invention.
Figures 6A and 6B are schematic vertical cross sectional views of various
flushing
configurations of a demister.
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Figures 7A-7B are schematic horizontal cross sectional views of a raw water
vaporization system showing different demister cyclone configurations.
DETAILED DESCRIPTION OF THE INVENTION
Rationale and Introduction
[0129] The subject invention seeks to improve the efficiency of the
vaporization of waste
water utilizing "waste" heat and pressure from a heat source such as an engine
(e.g. an
engine/generator combo unit or exhaust from steam generators, turbines,
boilers, flares, flame
exhaust and the like) so as to effect a reduction of the volume of raw water
and the
concentration of contaminants within the raw water and/or the exhaust gasses.
The invention
also provides a low-maintenance solution for water vaporization by reducing
the effects of
scaling. In addition, the invention may provide a more compact system in which
the need for
insulation to maintain fluid temperature is reduced or minimized.
[0130] In various embodiments, the invention also seeks to perform one or
more of the
following:
a. reduce the need for maintenance through the design and operation of a
system
that minimizes scale, particulate, salt and other build-up;
b. reduce ongoing operating expense and manpower due to minimized need for
operator oversight;
c. reduce or minimize new energy input over and above the primary heat source
from an ICE, combustion gas, flare gas or other similar source;
d. reduce the release of volatiles and pollutants to the atmosphere;
e. minimize pressure drop related to water vaporization and/or entrainment
separation;
f. maximize beneficial use of any available waste pressure and/or heat;
g. effectively use low grade waste heat to vaporize raw water;
h. effectively use low grade waste heat not typically suitable for another
industrial
purpose or optimally accessible for use close to its source;
i. reduce or minimize the creation and control of soapy foams associated with
some raw waters;
j. enable effective recovery of condensates from raw water;
k. enable recovery of re-condensed water for reuse;
I. reduce the capital cost of raw water vaporization equipment;
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m. provide a light weight and compact system for remote or satellite
installations
close to a heat source;
n. provide a light weight and compact system that can be made with plastics
allowing rapid mass production and the ability to custom manufacture and
configure various embodiments;
o. provide a modular system that can be built into either one unit or a
cluster of
units operating separately or in conjunction with one another;
p. provide a monitoring and reporting system for remote management of many
distributed systems, functions, products and resources within a larger grid;
q. reduce ground level footprint when installed or retrofit to existing
oilfield
equipment;
r. reduce or minimize the number of moving parts within a raw water
vaporization
system; and
s. reduce a ground level footprint of vaporization equipment when installed or
retrofit to existing oilfield equipment.
[0131] In another aspect of the invention, the invention provides
methods, systems and
apparatus for distributed management of raw water and internal combustion
engine (ICE) gas
emissions generated during industrial operations, including but not limited to
oilfield drilling,
completions and production operations with a mobile processing unit.
[0132] In another aspect of the invention, the invention provides systems
and methods
that at least partially utilize positive pressure waste within distributed
internal combustion engine
(ICE) exhaust sources as a substantially free energy for demisting input
pressure and/or
shearing force to increase or partially increase interfacial surface area
between raw water and
an engine exhaust gas for rapid mass and thermal transfer of engine exhaust
gas heat into the
raw water in order to vaporize a proportion of the aqueous phase of the raw
water and
concentrate contaminants within a residual raw water concentrate. The water
vapor generated
by the vaporization process may be demisted, discharged directly to the
atmosphere or
alternatively condensed by a condenser and captured for use.
[0133] The invention may also simultaneously facilitate rapid transfer of
at least a
portion of ICE combustion gas particulates and ICE combustion gas chemicals
into the raw
water as it concentrates.
[0134] The invention may also use an exhaust diversion system as means to
provide
exhaust heat and pressure to a region of a dual fluid interaction zone and
continued pressure
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force for demisting within the system in a manner that does not affect the
operation of an
associated ICE.
[0135] The invention may provide an economically viable and
environmentally
synergistic means of distributed raw water and emissions management to reduce
and/or recycle
large volumes of industrial raw water and emissions within localized regions.
That is, the
invention provides systems and methods to enable effective and efficient
processing of raw
water that is often remote and stranded from waste management infrastructure.
In one aspect,
the invention provides distributed management of raw water and emissions that
is enhanced by
networking data from remote raw water management processing units as a means
to ensure
that each satellite system in the network can be utilized to its full capacity
either by actors within
an organization operating within a geographic region/grid or by many
organizations operating
within a geographic region utilizing each other's raw water processing
system(s), salts, brine
fluids and/or condensed clean water vapor. An algorithm may be used as a means
to
communicate data points to those within the network such as individual system
run time, raw
water processing rates, available, accumulating or unused capacity, timing
and/or availability of
upcoming spare capacity, etc.
[0136] As described herein, part of the novelty of the present invention
is its simplicity.
[0137] Various aspects of the invention will now be described with
reference to the
figures. For the purposes of illustration, components depicted in the figures
are not necessarily
drawn to scale. Instead, emphasis is placed on highlighting the various
contributions of the
components to the functionality of various aspects of the invention. A number
of possible
alternative features are introduced during the course of this description. It
is to be understood
that, according to the knowledge and judgment of persons skilled in the art,
such alternative
features may be substituted in various combinations to arrive at different
embodiments of the
present invention.
Drilling Rigs, Gas Compression and Steam Generation Facilities
[0138] As is known, drilling rigs have high power requirements and are
typically located
away from the electricity grid. Hence, drilling rigs usually require that
electrical power is
generated on these often remote, stranded sites. A typical drilling rig may
have one or more
engines/generators used to generate power for various equipment and rig
operations including
the rig draw works, mud pumping, numerous auxiliary equipment as well as power
for the
personnel camps.
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[0139] At gas compression facilities, high power engines and compressors
are used to
effect gas compression of produced gases. A typical gas compression facility
may have one or
more engines/compressors that are operated to compress produced gases to high
pressure gas
delivery pipelines.
[0140] At steam generation facilities, high power boilers are used to
generate high
pressure steam. Waste heat from such boilers is usually passed through various
heat exchange
systems to recover heat that may be usable in the steam generation and other
processes prior
to venting to the atmosphere. Such waste heat that is vented to the atmosphere
is generally low
temperature and low pressure heat generally without a further industrial
benefit and not easily
accessible. That is, the waste heat may have low exergy (or a low amount of
useful energy),
wherein exergy is a measure of how much of the heat can be converted to work.
The exergy
content of heat depends on the temperature at which heat is available and the
temperature level
at which the reject heat can be disposed (usually the temperature of the
surroundings).
[0141] Figures 1A, 1B and 10 show further details of a typical gas
production and
compression facility that may be retrofitted to include the RVVVS's as
described herein. Typical
equipment at such a facility may include gas lines 4, flare stack 4a, produced
water tanks 4b
where production water (raw water) is stored, production gas storage tanks 4c
and facility
control building 4d. In accordance with the invention, one or more RVVVS's 10
(see Figures 10,
3A) are configured to engines 12 within compressor buildings 1 and one of the
production water
tanks 4e may be purposed to store concentrated brine as described herein.
Overview
[0142] The invention is primarily described with reference to gas
compression, drilling
rig, incinerator, gas turbine and steam generation operations although it is
understood that the
invention can be applied to other industries where the disposal of raw water
is required or where
engine exhaust, combustion gas and other heat source emissions are available.
[0143] Figure 2 is a schematic overview of a Raw Water Vaporization System
(RVVVS)
including the inter-related components that enable efficient water
vaporization in a system
with reduced maintenance requirements in accordance with one embodiment of the
invention.
As shown, the RVVVS is configured to an engine 12 associated with a muffler 2.
In normal
operation, the engine 12 produces power for various purposes, examples of
which are provided
above. The muffler 2 receives hot exhaust gases from the engine, muffles noise
and vents
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exhaust gases to the atmosphere. While Figure 2 is shown as being configured
to an engine 12
and muffler 2, it is understood that the engine 12 could be another combustion
gas source such
as a flare 4a, in which case, the muffler system may not be present. The
combustion gas source
may also be a gas turbine.
[0144] In accordance with one embodiment of the invention, a RVVVS 10 is
operatively
connected to the engine exhaust either upstream or downstream of the muffler
or both, so as to
divert engine exhaust to vaporization chamber 11.
[0145] More specifically, in operation, raw water is pumped from a bulk
raw water
storage tank 105 to a concentrator tank 107. The bulk raw water storage tank
may be a larger
tank (See 4b, Figure 1A) designed to hold raw water that has been collected
from one or more
sources (e.g. multiple gas production lines connected to one or more wells).
Bulk raw water
storage tank 4b may hold volumes of water typically in the range of about 50
m3 to 100 m3. As
shown in Figure 2, pump P1 pumps raw water to the smaller concentrator tank
107 (typically 1-2
m3) that is used to hold water being cycled through vaporization chamber 11.
In various other
embodiments tanks 105 and 107 may be the same tank. An optional filter 120 may
be included
to screen larger particulates from entering the pump P1 and concentrator tank
107.
[0146] In various embodiments, a VOC or H25 remover 126 may be added to
remove
Volatile Organic Compounds (VOC's), H25, or other compounds from the water
prior to
discharge into Concentrator Tank 107. One option would be to use traditional
stripping towers or
such as packed bed tower. In another embodiment an air-sparged hydrocyclone
may be
included to remove these readily evaporated compounds (e.g. light hydrocarbons
such as
benzene) from the liquid prior to the raw water being introduced into the
concentrator tank or
vaporization chamber.
[0147] Examples of air-sparged hydrocyclones can be found in US 4,279,743
(1981),
US 5,131,980 (1992) and US 5,560,818 (1996). In 2012 US 8,153,069 was issued
directed to
placing cyclones in series and adding a step of ultrasonics for so called
"cold boiling". In the
present technology, a number of hydrocyclones in series may help effectively
remove light
hydrocarbons. Having removed the hydrocarbons in a gaseous state, a condenser,
a chiller
and/or compressor may be used to return the gas to a liquid state for storage
and transport. Air-
sparged hydrocyclones alone does not necessarily create an economically
compelling reason
for removal of VOC's from production water. However, then used in combination
with the
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various elements of the present invention, such as a wastewater volume
reduction method
using free and waste energy, the removal of VOC's becomes economical providing
an
environmental benefit.
[0148] Pump P2 pumps raw water in a continuous cycle from concentrate
tank 107 to
vaporization chamber 11 where the raw water undergoes at least partial
vaporization and un-
vaporized water is returned to the concentrator tank 107. In this case, the
concentrator tank 107
is integrated directly below chamber 11. In other embodiments not shown,
vaporization chamber
11 may not be directly above tank 107 but instead be to the side, or offset
from above center. In
still further embodiments, more than one vaporization chambers 11 may be
configured to a
single concentrator tank 107 wherein the vaporized water is returned to
concentrator tank 107
from more than one vaporizer. In all various configurations, the dense
materials within the
chamber (e.g. liquids such as water and contaminates, and solids such as
scale) can fall directly
from the vaporization chamber into the concentrator tank. This may help reduce
maintenance
costs because, for example, if scale (e.g. solid CaCO3 deposits) builds up,
they can slough off
and fall directly into the concentrator tank where they may re-dissolve and/or
settle. That is,
positioning the tank 107 on a plane below the vaporization chamber may help
prevent scale
being stuck in elements or on surfaces of the apparatus where they require
cleaning or regular
maintenance.
[0149] The vaporization cycle in a primary embodiment is completed as
follows:
a) Pump P2 pumps raw water from the concentrator tank 107 into the
vaporization
chamber 11.
b) The raw water is ejected through nozzles against an exhaust gas flow from
the engine
12 within a vaporization chamber 11. This results in at least a portion of the
raw water
being sheared and vaporized as a result of the exhaust gas/raw water impact.
c) Unevaporated raw water is returned directly to the concentrator tank 107 in
a more
concentrated state than when initially introduced into the vaporization
chamber via pump
P2. The concentrator tank 107 may typically operate in a semi-batch mode where
P1
pumps raw water into the concentrate tank from bulk raw water tank 105 until a
high
level is reached in tank 107 and replenishes raw water within the concentrator
tank 107
when a low level is reached. In an alternative embodiment, P1 may be
controlled to
pump water from a storage source at the same rate at which water is being
vaporized. In
this latter case, the RVVVS is a continuous, non-batch operating system.
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d) Gas, possibly with entrained water, is then directed through at least one
demister 12b,
which in this embodiment is illustrated as a cyclonic demister, to separate
any entrained
water from the gas. The separated water is returned to the concentrator tank.
e) Demisted vapor is discharged to atmosphere.
f) Demisted vapor may pass through an optional condenser 113 in the event that
water
recovery is desired.
g) When the concentrator tank has sufficient raw water, P2 will continuously
pump raw
water from the concentrator tank 107 through the vaporization chamber 11 until
either
the raw water level within the concentrate tank reaches a low level or the
concentration
of brine within the concentrator tank 107 reaches a density threshold level.
h) If the low level is reached in tank 107, P1 will turn on and pump raw water
into the
concentrator tank 107 until the high level is reached.
i) If the brine concentration reaches a high density threshold level, P3
will activate to pump
concentrated brine solution to bulk concentrate storage tank 109 that stores
larger
volumes of concentrated raw water prior to final disposal or reuse. Additional
optional
filter 122 may be present to assist in the removal of fine particulates, such
as salt
precipitates, from the concentrated solution. P1 may also turn on to pump new
raw water
into the concentrator tank 107 while P3 and vaporization in chamber 11
continue to
deplete the volumes in tank 107.
j) Either way, when concentrator tank 107 is pumped out to a low level, P1
reactivates to
pump raw water into concentrator tank 107 to ensure sufficient water is in the
concentrator tank and to maintain adequate water volume through P2 to
vaporization
chamber 11.
[0150] As shown, in one embodiment when using pressure is desired, engine
exhaust is
diverted to the vaporization chamber 11 by valve systems V1 and/or V2. V1 is
shown configured
upstream of muffler 2 and V2 is downstream of muffler. In the preferred
embodiment, V1 valve
system is used to divert exhaust gas as the primary diversion system. In this
embodiment, V1 is
activated such that a portion (0-100%) of exhaust gas is diverted to the
vaporization chamber.
Importantly, V1 may be controlled to divert only a portion of exhaust gas that
does not adversely
affect backpressure on engine 12. That is, in the event that measured
backpressure on the
engine exceeds a threshold value, the V1 system will divert more exhaust
through the muffler 2
until the backpressure is below the threshold.
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[0151] As exhaust is diverted through the vaporization chamber 11, engine
noise may
be muffled due to the flow of raw water through the vaporization chamber, the
impact of engine
sound waves with the turbulent water within the vaporization chamber further
suppresses sound
waves. In addition, removal of heat from the gas to the liquid water may help
cause the volume
of the gas to decrease as it passes through the vaporization chamber. As such,
the pressure,
water and gas diversion within vessel 11 is effective to maintain noise levels
from the engine at
or below noise levels of exhaust being exhausted entirely through the muffler.
[0152] In one embodiment, the system is provided with V2 to redirect gas
passing
through the muffler to the vaporization chamber 11. However, as can be
appreciated, as V2 is
downstream of the muffler, the pressure, temperature of exhaust gas exiting
the muffler is lower
than at V1 and, hence, is less effective as a shearing, evaporating and
demisting energy than
exhaust gas diverted through V1 within a specific engines backpressure limits.
In various
embodiments as will be described herein, a fan or blower may be configured to
the inlet or outlet
of RVVVS 10 to at least partially assist engine pressure. Of course the more
pressure required
by an assistive blower, the greater the consumption of new input energy. From
an energy input
cost perspective and capital cost perspective higher supplemental energy input
is less desirable
when there is waste ICE pressure that can be utilized.
[0153] The valve systems will preferably be provided with fail safe
systems such that in
the event of inadvertent or unexpected changes in pressure, V1 or V2 will
automatically open or
partially open to divert some or all exhaust gases to atmosphere through the
muffler so as to
maintain the desired performance of the engine and its associated equipment.
[0154] In the embodiment shown in Figure 2, the gas conduit comprises a
"Y" or "Tee"
shaped pipe, and the gas conduit includes:
a release valve V2, the release valve configured when open to allow gas from
the gas
source to be vented into the atmosphere either directly or through an adjacent
muffler
and when released allows the valve to close or partially close and to direct
at least a
portion of gas towards the vaporization chamber; and
a control valve V1 configured when open to allow gas to be directed to the
vaporization
chamber and when closed to prevent gas being directed to the vaporization
chamber.
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[0155]
In some embodiments, the "Y" or "Tee" shaped pipe may be configured such
that, when air is diverted away from the vaporization chamber (e.g. through
the muffler), a
negative pressure is applied to the channel leading to the vaporization
chamber to draw air in
counter-flow from the gas inlet. That is, in this configuration rather than
hot gas being provided
to the vaporization chamber, atmospheric air is drawn back through the system.
This may allow
the system to be cooled more quickly due to this airflow.
[0156]
It will be appreciated that the valves (e.g. V1 and V2) and/or pumps (e.g. one
or
more of pumps P1-P5) may be controlled by a controller 111. The controller may
comprise a
processor, memory and computer program code. The computer program code may be
stored
on a non-transitory medium such as a CD or DVD. The computer program may
receive inputs
from sensors configured to monitor the temperature of inlet and outlet gas,
inlet and outlet
water, density of water, etc.
[0157]
Further details and embodiments of the vaporization chamber, concentrator tank
and demister are described below.
Raw Water Vaporization System
[0158]
Figure 3A-3M shows more detailed perspective and cross-sectional views of a
raw water vaporization system 10. To clarify how materials in different states
are separated, in
figures 3A-3C, the motion of liquid is shown by line arrows with solid arrow
heads, whereas
the motion of gas is shown by block arrows, E>.
[0159]
As shown in Figure 3A, in this case, the raw water vaporization system (RVVVS)
comprises:
a vaporization chamber 11 having:
raw water 222 and gas 226 inlets configured inject water and gas to within the
vaporization chamber to effect raw water vaporization and
an outlet 231 at the bottom of the vaporization chamber 11;
a concentrator tank 107 positioned in a plane below the vaporization chamber
1,
(in the illustrated embodiment it is directly below) such that material
exiting the
vaporization chamber via the vaporization chamber outlet impinges with liquid
in the
concentrator tank 107;
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a raw water channel 104 configured to inject raw water from the concentrator
tank 107 into the vaporization chamber 11 via at least one of the illustrated
raw water
inlets 222.
Vaporization and Capture of Raw Water
[0160] In this case, as shown in Figure 3B, the gas inlet 226 is
configured to direct gas
flow through the vaporization chamber 11 and directly into liquid contained in
the concentrator
tank 107. This is achieved in this embodiment by providing a direct line of
sight between the gas
inlet 226 and the surface of the liquid contained in the concentrator tank
107. This may help
redirect unevaporated water directly into the water body contained in the
concentrator tank 107,
assisting in the demisting process by coalescing through gravity and droplet
adsorption. In one
embodiment this is considered a coalescing or pre-demisting step that helps
remove entrained
droplets from the gas stream prior to the gas stream exiting the tank 107 into
demister 12a.
[0161] In this case, water is injected into the vaporization chamber
through nozzles
222a-d. In this case, the nozzles are arranged to be directed radially inwards
to the axis of flow
of the gas ejected by the gas inlet 226. In this case, there are two levels of
nozzles (222a and
222b form part of a first level and 222c and 222d form part of a second
level), each comprising
8 radially and inwardly directed nozzles. The water flow may be sheared by
passing though the
nozzles then sheared further through interaction of the liquid flow from the
nozzles 222a-d with
the gas flow velocity from the gas inlet 226.
[0162] In the interaction zone 11a within the vaporization chamber the
hot gas is
configured to vaporize (e.g. boil and/or evaporate) liquid from the water
flow. Any un-vaporized
water is forced downwards towards the liquid contained in the concentrator
tank by gravity (by
virtue of the concentrator tanks position below the vaporization chamber) and
by the motion
imparted to the water droplets by the gas flow. Contained in this gas flow is
among other things,
water droplets and dry particles of various sizes.
[0163] As shown in Figure 3a, in one embodiment the area of the outlet is
a significant
portion of the area of the vaporization chamber. For example, the ratio of the
outlet area to
vaporization chamber may be greater than 1:10 (or greater than 1:5; or greater
than 1:2). This
ensures that material is not impeded from exiting the vaporisation chamber.
The outlet 231 in
this case is tapered to direct fluid flow towards the surface of the liquid in
the concentrator tank.
However this taper is configured such that the angle of the taper with respect
to horizontal is
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greater than 30 (e.g. greater than 45 ). This helps prevent scale or other
solids remaining
within the vaporization chamber. That is, the vaporization chamber is a simple
open structure
with upright side walls and a tapered or completely open bottom to easily
allow materials to be
ejected from the inside of the vaporisation chamber.
[0164] Another function of the tapered outlet 231 is as a coalescing cone.
The
coalescing cone is a narrowed portion of the vaporization chamber downstream
of the
vaporization zone. By reducing the cross-sectional area of the gas and liquid
droplet flow, the
coalescing cone re-entrains both water and gypsum formed during the water
shearing and
vaporization process upstream. This helps lower the PPM count in the condensed
water from
the exit. It will be appreciated that other coalescers may be used. For
example, rather then a
cone the coalescer may comprise a diffuser plate with multiple holes in it to
diffuse and coalesce
the water and particulate from the gas flow. The holes may operate in a
similar way to the cone
by restricting the cross-sectional area of the gas and liquid droplet flow.
[0165] Other means of coalescing may be employed along with, or in place
of, the
tapered outlet 231 such as a forced change of gas flow direction by a chimney.
For example,
one of the design targets of the present invention is to minimize or reduce
the pressure drop
through the entire RVVVS which minimizes or reduces electrical or other power
consumption to
run the system effectively. By employing a change of direction of the gas flow
downstream the
vaporization chamber and sacrificing perhaps 0.25-3"WC (pressure), water
droplets and
particles with a similar mass of salt of >100um can be adsorbed into the water
in the
concentrator tank. For example, a chimney, cone or other such means of gas
flow delivery,
flowing generally downwards toward the top face of the water in the
concentrator tank, would be
designed to that the outlet of the chimney would be 1-24" above the surface of
the water.
Depending on that distance and acceptable system pressure, the system may be
configured to
effectively demist, coalesce and adsorb droplets ranging from 20um to larger
then 100um. One
of the limits on the pressure and distance design would be to ensure the
pressure is sufficient to
break the surface tension of the water in the concentration chamber thereby re-
entraining new
droplets.
[0166] In one preferred embodiment, structured packing or other such
device of known
art (not shown) may be used at or near outlet 231 as a means of coalesce. In
FIG 2, the
coalescing means in one embodiment may be positioned between Chamber 11 and
Tank 107.
Larger droplets are easier to separate from the combustion gas stream using
mechanical
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means. Larger droplets in a RVVVS can advantageously be at least partially
separated utilizing
gravity and/or vector or centrifugal force via change of direction, thereby
reducing the
requirements of new energy to power demisting function within the overall
RVVVS. With regard
to particles that form in the vaporization, such as salt, calcium based
particles, gypsum or the
like, the use of this coalescing step has been shown to substantially reduce
dry particles <50um
in the gas stream. When sizing a demisting device for geometry and pressure
drop, it is
advantageous to have a pre-coalescing step reducing or minimizing the need to
have a high
pressure drop device targeted at particles <20um, <10um, <2.5um, and <1um.
[0167] A drawback of prior art systems is that the final demisting step
(for example a
Chevron mist pad), at the tail end of the gas circuit, is typically designed
to separate out of the
gas stream the smallest particles and droplets, typically down to <20um,
<10um, <2.5um, and
<1um. This design practice leads to higher pressure drop and substantial
cleaning and
maintenance, resulting in system downtime. The demisting process in all cases
will then have a
wet and dry boundary between the inlet and outlet of any demisting system
which needs
periodic cleaning and downtime. The economic value of a RVVVS is diminished
when
maintenance requirements are high and when power consumption is higher than
necessary.
The process and steps herein described as a multi-step gas entrainment
separation help
provide the advantages of lower pressure drop, less maintenance and less
system downtime
than any prior art system.
[0168] This multi-step entrainment removal process can effectively limit
the design of the
final demisting step to separate particles and droplets ranging between 20-
100um, as an
example, because particles <20um are adsorbed within the structured packing
step and the
droplets above >100um are adsorbed by the change in direction step. As
described herein the
middle droplet size range can vary depending on how each sub-step is
engineered. For clarity
the steps for one embodiment are as follows: Step 1, employ a means to adsorb
small particles
(e.g. <100um, <50um, <20um, <10um, <2.5um, etc.) and coalesce small droplets
into larger
droplets; Step 2 employ a means to utilize gravity or force to separate larger
droplets (eg,
>50um, >100um, >200um, etc.); Step 3 employ a final demisting step for the
remaining
entrained droplets and/or particles.
[0169] As a result of the techniques described herein, a preferred
embodiment of the
present invention has a total overall pressure drop of 0-10"WC, 0-7"WC, 0-5'WC
and <3"WC.
An RVVVS with a total system pressure drop of <5-7"WC makes available the
ability to utilize the
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pressure from ICE exhaust without the need for additional power to move the
gas through the
system via use of the fan or blower.
[0170] In this case, the concentrator tank is not configured to be filled
up to the bottom
of the vaporization chamber. Therefore, there is always a headspace 107a (or
ullage) at the top
of the concentrator tank 107a as shown in Figure 3B. This headspace 107a
provides a channel
which receives the gas and liquid from the vaporization chamber. The gas may
comprise
vaporized raw water and gas from the heat source (e.g. engine). The liquid
will comprise un-
vaporized water. In addition, any solids generated by the vaporization process
(e.g. scale or
particulates) will also fall through this headspace from the vaporization
chamber 11.
[0171] In this case, the concentrator tank has gas outlets 107b arranged
in the top
surface of the concentrator so that gas entering the concentrator tank
headspace 107a from the
vaporization outlet must change direction to exit the concentrator tank gas
outlets. This may
help aid separation in two ways: firstly gas is more mobile and so the can
change direction more
easily than the liquid which is directed into the liquid already in the
concentrator tank; and
secondly, liquid is more dense than gas so the liquid will inherently
gravitate towards the surface
of the liquid in the concentrator tank 107. In this way the concentrator tank
can directly receive
concentrated raw water from the vaporization chamber 11.
[0172] Another possible advantage of positioning the concentrator tank
directly below
the vaporization chamber is that the heat of the vaporization chamber is
transmitted to the
contents of the vaporization chamber. Heat transmission may include directly
receiving heat
from the warmed un-vaporized droplets of concentrated raw water as well as
receiving heat
from the warm gas flow across the liquid surface in the concentrator tank.
This helps allow water
injected into the vaporization chamber from the concentrator tank to be
injected at a higher
temperature which may allow for more efficient vaporization.
Concentrator Tank
[0173] The concentrator tank in this case is a storage tank configured to
provide raw
water to the vaporization chamber where the water is at least partially
vaporized then the
remaining liquid is returned to the concentrator tank. Therefore, in the
absence of additional
flows, the water is recycled between the concentrator tank and the
vaporization chamber such
that amount of liquid water is diminished (i.e. by being turned into a gas)
and such that the
concentration of contaminants within the liquid water is increased.
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[0174] In this case, the concentrator tank is configured to pump raw
water out of the
concentrator tank and into a storage container using pump P3 when the liquid
within
concentrator tank 107 has reached a threshold concentration of contaminants,
or density.
Removing concentrated water lowers the level liquid within the concentrator
tank. This allows
the surface of the liquid stored in the concentrator tank to fall below the
level of an angled baffle
195 for removing floating contaminants 197 (e.g. hydrocarbons). Of course, the
vaporization of
water within the vaporization chamber will also cause the level of liquid
within the concentrator
tank 107 to lower.
[0175] In this case, the concentrator tank is configured to receive new
raw water (i.e.
which has not been passed through the vaporization chamber) from a bulk water
tank (e.g. 105
in Figure 2) when the level of water in the concentrator tank 107 falls below
a threshold level.
The addition of new raw water raises the level of liquid and directs the
floating contaminants 197
along the bottom of the angled baffle and into a condensate tank (not shown),
where it can be
pumped into a bulk condensate recovery tank.
[0176] That is, in operation, the level of raw water in the concentrator
tank 107 cycles
between the high and low levels. The baffle 195 is configured to funnel any
floating components
197 above the water line into a narrow vertical channel as the water in the
concentrator tank
107 rises. This has the effect of increasing the vertical height of the
floating components 197
such that they overflow into the overflow or condensate chamber 192 (see
figure 2) when the
water level in the main chamber 191 reaches its maximum height. This allows
these floating
components 197 to be removed from the raw water so that they are not recycled
through the
vaporization unit and to be stored as they may be a valuable byproduct of the
process including
recoverable hydrocarbons. The overflow chamber 192 may be configured with
level switches
which activate a further pump P4 to control the level of fluids in the
overflow tank.
[0177] The concentrator tank in this case has a recirculation loop (P5)
for recirculating
the liquid within the concentrator tank. This helps control the level of
stratification and/or
flocculation of density or temperature within the concentrator tank 107 which
may occur due to
the concentration of contaminants affecting the density of the liquid and/or
that may cause
aggregation of particles that may trap unevaporated water. It will be
appreciated that, in other
embodiments, the concentrator tank may comprise an agitator. In another
preferred
embodiment not shown, P5 is not required and wherein P3 is used as a tank 107
circulation
pump when it is not diverting brine to tank 109. To accomplish this, a tee
joint in the flow line
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and a couple solenoids can be automated to facilitate redirecting the fluid
flow. In this
embodiment P3 draws water from the bottom of tank 107.
[0178] In this case, the concentrator tank 107 is tapered at the bottom
and the
recirculation loop 107c is configured to remove liquid from the tapered
bottom. This may help
ensure that scale does not build up at the bottom (i.e. where the liquid is
likely to be densest
and have the highest concentration of contaminates). The taper may be conical
(as depicted in
Figure 3A) or rounded. It will be appreciated that a rounded bottom tank may
have a smaller
height to volume ratio than a conically shaped tank, and so may be more
compact. In a
preferred embodiment P3 is inline 107c and P5 does not exist. When the water
density in tank
107 reaches an upper threshold, P3 would divert all or a portion of the flow
to a brine storage
tank 109.
Demister
[0179] Although much of the un-vaporized water will directly impinge on
the surface of
the liquid in the concentrator tank, small droplets may be retained in the gas
flow and be
directed towards the concentrator tank gas outlets 107b which are in this case
are positioned at
the top of the concentrator tank. This first water separation step removes the
need to use
cyclone separation pressure from having to spin all water volume traveling
through a
vaporization chamber. This energy savings allows any cyclonic separation
system to only
consume energy relating a much smaller volume of entrained liquid resulting in
higher
separation efficiency, lower cyclone water loading and lower pressure drop
across a cyclone
demisting system. In one embodiment, to recapture the water droplets which
remain entrained
in the gas flow, each of the concentrator-tank gas outlets 107b lead into a
cyclone demister 12a,
12b. Demister 12b is shown separately in Figure 30.
[0180] The demister 12b in this case comprises a circularly symmetric
body 283 (e.g.
cylindrical or frustoconical) with a rotational-flow inducer 280 (e.g. a
stator or an actively or
passively driven rotor) at one end of the demister body; a gas outlet 281 at
the other end of the
demister body; and a outlet 282 at the bottom of the demister 12b. Gas and
entrained solid or
liquid material entering the demister through the rotational-flow inducer 280
is induced into
rotational motion within the demister body 283. This imparts a centrifugal
force on the entrained
solids and/or liquid droplets which impinge on the inner surface of the
demister body 283 and
fall to the bottom where they can exit through the outlet 282. The second
outlet in this case
comprises a channel which connects the demister 12b with a position below the
liquid level of
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the concentrator tank 107. In this way, gas cannot enter into the demister
from the headspace
107a of the concentrator tank 107 via the demister liquid outlet 282.
[0181] In this arrangement, the gas passes upwardly through the demister
12b. This
means that there are two competing forces being applied to the liquid and/or
solids: gravity
which tends to draw the high-density materials downwards; and the air flow
which tends to draw
the high density materials upwards. To ensure that some high-density materials
are not retained
within the demister at a point where gravity and air flow forces are balanced,
embodiments may
be configured to provide a time-varying airflow pattern (e.g. with passive or
active elements), or
to design the curvature of the demister body wall to help preclude dead-spot
positions (where
forces are balanced).
[0182] Gas exiting the demisters, in this case, is then aggregated in a
gas manifold 285
and allowed removed from the device via a flue 286. In various embodiments one
or more
optional blowers 287 at the outlet of the gas manifold provide a negative
pressure within the gas
manifold which encourages air flow through the vaporization chamber 11, the
headspace 107a
within the concentrator tank 107 and the demisters 12a, 12b. This in turn may
reduce the
amount of back pressure exerted on the engine and so allow greater throughput
without
exceeding engine tolerances. In various embodiments blowers 287 are not
required as the
engine pressure is enough to force exhaust gasses through the engine RVVVS 10
without
exceeding backpressure limitations of the engine, including pressure needed to
provide a
comfortable safety margin. In another embodiment when the RVVVS is configured
to a flare
stack void of substantial pressure, optional blower 287 may be employed to
facilitate all of the
pressure required to suck gas though the RVVVS.
[0183] In this case, the RVVVS comprises multiple demisters arranged in a
circle around
the vaporization chamber. Using multiple cyclone demisters with a smaller
radius allows a
greater proportion of the high-density material to be removed because smaller
radius cyclone
demisters allow a greater centrifugal force to be applied for the same gas
speed. Put another
way, multiple smaller cyclone provide greater separation efficiency for less
pressure drop when
compared to a larger, single cyclone demister. When seeking to re-condense the
vaporized
water for further industrial use, it becomes important to separate gypsum,
droplets and particles
of the smallest size possible in order to achieve the lower TDS in the
condensed vapor stream.
For example, for a given inlet gas flow of 30000FM at 3000, a single
frustoconical cyclone
separator with an inlet diameter of 24" may experience a pressure drop of
3.5"WC and separate
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salt particles of 20um and greater. Where as using 4 smaller 12" diameter
cyclones may have
the pressure drop of less than 1" and the capacity to separate salt particles
down to 12um. This
may be the difference between re-condensed water having 6,000ppm salt
(considered brine) or
300ppm salt (considered drinking water).
[0184] In other various embodiments a cyclonic demister may not be used
in favor of
another style, for example impingement bases demisters. In other embodiments,
geometry with
narrow outlets, direction change and pressure may be used to fully or
partially demist the gas.
Raw Water Shearing and Vaporization
[0185] It will be appreciated that the embodiment of Figure 2, 3A-30
represents one way
of effecting evaporation according to the present invention. There may be a
range of variants
and optional features which may be included while remaining within the scope
of the invention.
By way of example, the demisting system may be positioned above and in the
center of the
concentrator tank 107. In another embodiment the air knife and vaporization
chamber may be
positioned to the side, adjacent to and/or above or inline with the high water
level of tank 107. In
the latter example, the un-vaporized water flowing from at least one vaporizer
11 to at least one
tank 107 would do so in a downward flowing directions. In other various
embodiments, at least
one vaporization chamber 11 would be positioned beside tank 107 in which case
the un-
vaporized water would have to flow from the vaporization chamber into tank 107
via water level
head pressure.
[0186] In the embodiment shown in Figure 3, the exhaust gas inlet into
the vaporization
chamber is an orifice with a slightly narrowed tapering bore with respect to
the full bore with of
the gas conduit. This has the effect of controlling and/or increasing the
velocity of the gas at the
point of entering the vaporization chamber. This higher relative velocity may
help shear the
water flow to create a larger number of smaller-sized droplets, sub-micron
droplets, mist and
fog. This increases the surface area to volume ratio of the water droplet
which increases the
rate of vaporization due to enabling rapid thermal transfer of the heat in the
gas into the water.
[0187] As shown in Figures 4A-4F, raw water shearing and vaporization may
be at least
partially achieved as a result of the push pressure of the exhaust gas (or
blower motor, or a
combination of engine exhaust gas with partial assistance of a blower) in
combination with the
shearing forces imparted on the raw water from the exiting nozzles, or other
water discharge
device or system delivering raw water to vaporization zone 24a (where the
liquid raw water
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interacts the hot gas to effect vaporization) under any range of engine or
blower pressure from
very little pressure to high pressure, and the subsequent impact and/or mixing
with the exhaust
gas stream.
[0188] In one embodiment, within the zone 24a, raw water is pumped
through a nozzle
or nozzle system, or other water discharge device or system (herein sometimes
referred to as a
nozzle or nozzles) that will create an initial amount of raw water surface
area and/or initially
atomize at least a portion of the water into droplets at the moment of exit
through the nozzles or
discharge device. In this embodiment, as a result of the positioning of the
nozzles relative to the
exhaust stream, the water droplets are immediately impacted by high
temperature and/or rapidly
flowing exhaust gases which will further impart shearing forces on the water
droplets.
[0189] Depending on the particular parameters of the system at a given
time including
raw water flow rate, nozzle design, exhaust gas temperature, exhaust gas
pressure and flow
rate, and position of the nozzles, a desirable rate of vaporization of raw
water will occur resulting
in the creation of water vapor and concentrated raw water contaminants.
[0190] As shown in Figures 4A-4F, the interaction of raw water with the
exhaust can
occur in a number of ways to impart shearing forces and/or turbulence as a
means of interfacial
surface area generation and therefore desirable thermal and mass transfer.
Further, these
Figures also illustrate various separate and combined examples of optional
exhaust delivery
devices or systems herein sometimes referred to as air knives, the air knives
configured directly
to deliver exhaust gas 14a from an exhaust system 14 to a vaporization chamber
11. Various
optional air knives may be configured and utilized as a means to manipulate
the exhaust gas
pressure, velocity, delivery orientation and/or speed prior to the delivery of
the exhaust gas 14a
into interaction zone 24a.
[0191] An air knife may be considered to be a component of a pressurized
air channel
containing a series of one or more holes or slots through which pressurized
air exits in a laminar
flow pattern. That is, the holes and/or slots may be sized and positioned such
that the individual
air flows combine to produce a laminar flow pattern. The air knife may be
straight or curved. The
air knife may extend along an axis (e.g. straight or curved axis) and have a
restricted lateral
dimension. The exit velocity of the pressurized air from the air knife may be
one or more of:
between 20-60m/s; 40-60m/s; between 40-80m/s; between 50-100m/s; and greater
than
100m/s.
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[0192] For example, in Figure 4A, exhaust piping 26 conveys exhaust gases
14a to
interaction zone 24a where raw water 22b is sprayed countercurrent to the
exhaust gas flow.
The entry point of exhaust piping 26 to zone 24a may be tapered to expand the
transition zone
which may be used to create areas of lower pressure.
[0193] Figure 4B shows a straight piping embodiment together with
potential positions
and angles of the raw water spray 22b, including concurrent flow,
countercurrent flow, angled
flow and right-angled flow that may occur within piping 26 and/or zone 24a.
[0194] Figure 40 shows an embodiment with an exhaust diverter 26a that
may be used
as a means to create a radial flow pattern with a low pressure or void space
in the center while
maintaining the exhaust pressure at a level as it enters zone 24a by
maintaining the cross
sectional area of the piping at a given value at the point of entry. In
another embodiment 26a
enables compression and diversion of exhaust gasses to increase gas flow speed
as it enters
zone 24a when compared to gas flow speed prior to diverter 26a. A system may
be employed to
adjust the position of the diverter 26a to maintain a consistent gas velocity
as shown by the
double-headed arrow.
[0195] Figure 4D shows a decoupled exhaust delivery system as an
embodiment where
ambient air 26b may be introduced to a first gas stream 14a to decrease
exhaust gas
temperature prior to entering zone 24a. This embodiment may also or
alternatively allow any
water/moisture within the gas or from zone 24a or water distribution system to
drain through the
decoupled or partially decoupled area. The decoupled area may be configured as
a means to
drain raw water and/or raw water concentrate from a vaporization chamber or an
air knife,
depending on the configuration. Figure 4E shows an embodiment with an exhaust
diverter/compressor 26a where the compressor constricts or reduces the cross-
sectional area of
the piping 26 to increase the pressure and therefore speed of the exhaust gas
14a as it enters
zone 24a. As illustrated in 4E the exhaust diverter/compressor is placed in
the center of a pipe
as a means to divert and/or compress exhaust gas flow, however it should be
understood that in
various other configurations the cross sectional area may be reduced by
overall pipe diameter
reduction or any other means of compressing or diverting a gas flow to create
a desired gas
entry pressure and speed as the gas enters zone 24a.
[0196] Figure 4F shows a plan (I), side (II) and front (III) view of a
"duck-bill" exhaust
nozzle as an example of a means of constricting or expanding the cross-
sectional area of the
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piping 26 to increase or decrease exhaust gas pressure and therefore speed as
it enters zone
24a. In this example, the nozzles may be placed at 90 degrees to the flow of
the exhaust gas as
one example of the possible positioning. In another embodiment the nozzle may
be a flat fan
nozzle to enable the delivery of raw water across the gas delivery shape as it
enters zone 24a
[0197] In various embodiments, any configuration illustrated in Figures
4A-4F or
described herein may be configured with louvers as a means of further
controlling, managing or
manipulating gas flow characteristics as the gas flow 14a enters zone 24a.
More specifically, the
latter may be configured to allow a throttling of gas pressure as a means to
control gas flow
speed or pressure as a means for enabling a consistent exhaust gas 14a speed
and/or speed
range as its being delivered to and entering zone 24a. This configuration may
be desirable to
maintain a consistent range of interaction of raw water and delivered exhaust
gasses at times
when the engine load various in a manner that creates fluctuations of engine
exhaust gas flow,
pressure, speed and/or temperature. By way of example if Figure 4B is
configured with louvers,
not shown, they may remain fully open when the engine is under 80% load.
However if the
engine load were to decrease to, for example 50%, and thus decrease the total
exhaust gas 14a
flow rate and/or temperature, the louvers would choke the cross sectional area
in which the
exhaust gas enters zone 24a. This choking or reduction of cross sectional
surface area under
reduced gas flow conditions thereby enables a consistent range of gas flow
speed range as it
enters zone 24a.
[0198] As another means of providing a consistent range of desirable
exhaust gas
speed to zone 24a, in various embodiments, the exhaust diversion device 14b
may be weighed
such that upward fluctuations of gas pressure from increased engine load would
be vented to
atmosphere. In the latter example, 14b may be configured to divert all of the
exhaust gas 14a to
zone 24a when the pressure between an air knife illustrated in 4A-4F and
engine 12 is less than
10"WC or other desired threshold, however if this pressure increases above the
10"WC due to
increased exhaust gas flow form increased engine load exceeded the excess
exhaust flow
would be permitted to vent to atmosphere.
[0199] Nozzles or other means of distributing raw water within exhaust gas 14a
may include full
cone nozzles, flat fan nozzles, hollow cone nozzles, atomizing nozzles, open
piping, gravity
waterfall system or other known systems. The pressure of raw water
distribution may vary from
gravity distribution to high pressure. When choosing a water pressure droplet
size and raw
water distribution characteristic and how they interact with the pressure and
temperature of
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exhaust gas must be considered. For example the higher the pump pressure at a
nozzle head
of a hollow cone nozzle, the smaller the average droplet size and droplet mass
of raw water
droplets exiting the nozzle and therefore the greater the surface area of the
average droplet
related to its mass (or volume).
[0200] Since interfacial surface area is desirable as a means of thermal
transfer of heat energy
into the water and mass transfer from a liquid to gaseous state, the smaller
the average droplet
size the faster the thermal transfer takes place. Continuing, the average
droplet size of the raw
water exiting the water nozzle create the starting average droplet size for
which the pressure
within the exhaust gas flow must act against as shearing force. Combined, the
pressure of the
pump and the pressure of the exhaust gas act on the raw water to shear it as a
means of rapid
thermal transfer. Further, a suitable water pump can be chosen to accommodate
the scale of
system based on system specific needs, but generally based on engine exhaust
specifications.
In one embodiment, a pump pressure of 10-100psi is suitable. Pump type is
preferably a
centrifugal pump due to their ability to pump waste water and slurries plus
desired draining
characteristics, however other pumps such as positive displacement, diaphragm,
screw or other
known pump types may be used.
Back Pressure and Engine Parameters
[0201] Depending on the engine, the back pressure on the engine is
controlled to
ensure compliance with the engine specifications. For example, a typical
drilling rig
engine/generator such as a CaterpillarTM 400 ekW 500 kVA gen set may require
that the back
pressure is below 40 inches WC. In various embodiments the RVVVS can be
operated with
about 5-20in WC, typically 8-12in WC back pressure. Importantly, in one
embodiment, a
pressure sensor or switch monitoring system backpressure at or near the base
of on engine
exhaust system near the engine block itself may be employed and configured
with a control
system and an engine exhaust diversion system to allow the exhaust 14a to flow
to atmosphere
in the event the total system backpressure exceeds a minimum threshold. In one
embodiment,
this threshold may be 5-40 in WC, or in other embodiments may be 5-20 in WC.
When
configured to a combustion gas source with no available "free" pressure,
pressure within the
system may be 0-20 in WC or below 5 in WC. In some embodiments configured with
a blower or
fan, certain flow zones within a system may be under slightly negative
pressure. It may be
preferable to design the entire system to have as low of a pressure drop as
possible in order to
consume less power if using a blower and to use minimal engine pressure as
possible if
configured to an engine.
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[0202] Exhaust temperatures for operating 250-1500 kW engine/generators
will typically
be in the range of 350-500 C but may range from 200-700 C. Exhaust gas flow
rates for these
example sizes may be in the range of 3400-8500 cfm (cubic feet per minute) and
heat content
rejection to exhaust gas may typically be in the range of 25,000-60,000
Btu/min. As a result, the
total amount of heat available for vaporization can be determined based on
known engine
parameters and operation which can be used for effective control of the RVVVS
as will be
explained in greater detail below.
[0203] Generally, the energy transformation chain within the system is as
follows:
a. The engine/generator transforms the chemical energy of the engine fuel to
mechanical energy and heat.
b. A portion of the heat and pressure losses from the engine/generator are in
the form
of exhaust gas and are diverted to the RVVVS 10 and/or a vaporization chamber
11.
c. The kinetic energy of the exhaust may be increased between the engine and
zone
24a by compressing, controlling or manipulating the gas against the engine
pistons
pushing the combusted exhaust gas from the engine block into an exhaust system
and/or adding kinetic energy through multiple gas streams.
d. The kinetic energy of the exhaust gas contributes to the atomization and/or
surface
area generation of raw water coming into contact with the exhaust gas through
shearing forces which increases the interfacial surface area of water and gas
as a
means for increasing thermal and mass transfer between the exhaust and raw
water
droplets.
e. The heat of the exhaust gas effects at least partial vaporization of raw
water droplets.
Downward Flow Demister
[0204] Figure 5 shows an alternative embodiment of the present invention.
Like the
embodiment of Figure 3A, this embodiment of a raw water vaporization system
(RVVVS)
comprises:
a vaporization chamber 511 having:
raw water 522 and gas 526 inlets configured inject water and gas to within the
vaporization chamber to effect raw water vaporization and
an outlet 531 at the bottom of the vaporization chamber 511;
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a concentrator tank 507 positioned directly below the vaporization chamber 511
such that material exiting the vaporization chamber via the vaporization
chamber outlet
impinges with liquid in the concentrator tank;
a raw water channel 504 configured to inject raw water from the concentrator
tank 507 into the vaporization chamber 511 via at least one of the raw water
inlets 522.
[0205] In this case however, the demisters 512a, 512b are inverted with
respect to the
orientation of the embodiment of Figure 3A. That is, the airflow is configured
to be directed
through one or more air channels upwards before entering the demister at the
top.
[0206] Like the demister shown in Figure 30, each demister 512a, 512b in
this case
comprises a circularly symmetric body (e.g. cylindrical or frustoconical) with
a rotational-flow
inducer (e.g. a stator or an actively or passively driven rotor) at one end of
the demister body; a
gas outlet at the other end of the demister body; and a liquid outlet at the
bottom of the demister
12b. However, the rotational-flow inducer in this case is located at the top
of the demister and
the gas outlet is located at the bottom of the demister.
[0207] Gas and entrained solid or liquid material entering the demister
through the
rotational-flow inducer is induced into rotational motion within the demister
body. This imparts a
centrifugal force on the entrained solids and/or liquid droplets which impinge
on the inner
surface of the demister body and fall to the bottom where they can exit
through the liquid outlet.
[0208] In this case, each demister has a separate gas outlet. However, in
other
embodiments, the gas outlets may be connected to a manifold for aggregating
the gas for
ejecting into the atmosphere. It will be appreciated that aggregating gas
flows into a single outlet
may allow the plume from the system to be projected to higher altitudes which
may be
preferable.
[0209] Another option for improving the projection of the gas from the
exhaust is
diverting a portion of hot combustion gas 14a from the exhaust piping 26
directly into the
manifold 285 or into the flue 286. That is, in other embodiments a portion of
combustion gas 14a
may be diverted from upstream of the vaporization chamber 11 and/or AK 226 and
directed into
RVVVS exhaust header or gas manifold 285 or exhaust circuit (e.g. flue 286) to
increase the exit
temperature. This helps facilitate the creation of a larger dispersion cloud
and less visible vapor
plume.
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[0210] The liquid outlet in this case comprises a channel which connects
the demister
512b with a position below the liquid level of the concentrator tank 507. In
this way, gas cannot
enter into the demister from the headspace of the concentrator tank 507 via
the demister liquid
outlet.
Demister Flushing
[0211] The function of the demister is to separate entrained water from
the gas flow
before the gas is ejected into the atmosphere. Within the demister precipitate
or scale may form
which may require maintenance, depending on may other various parameters of
the overall
system. For example, one could ensure the cyclone separators remain dry and
separate out
only gypsum particles which would drain via 282 FIG 30. Alternatively, the
cyclones could be
run wet wherein un-vaporized liquid is discharged from the cyclone via 282 FIG
30. The water
flow in the vaporizer from P2, the water pressure of the nozzles 222x, the
velocity of gas 14a
and share of air knife 26, the shape of the optional coalescing cone preceding
opening 231 and
the ratio of head space 107a are all factors.
[0212] To mitigate the build of scale, the demister may be periodically
washed with
water. This will help dissolve scale or precipitate which has built up within
the demister. Figures
6A and 6B illustrate two options for flushing a demister. It will be
appreciated that other flushing
mechanisms may also be used.
[0213] In Figure 6A, the feed water is pumped from raw water tank 105 via
P1 into the
top of the demister 612a. This water flows downwardly through the demister and
can exit either
through the rotational-flow inducer and/or through the liquid outlet at the
bottom of the demister.
In both cases the flushing water will return to the main body of the
concentrator tank below.
[0214] Figure 6B shows an alternative flushing arrangement where raw water
flow from
105 is pumped upwardly via P1 from the bottom of the demister 612b. Once the
water is
introduced into the demister gravity causes the water to flow downwardly
through the demister
where it can exit either through the rotational-flow inducer and/or through
the liquid outlet at the
bottom of the demister. In both cases the flushing water will return to the
main body of the
concentrator tank below, in both cases the cleaning and salt/scale dissolving
action is
conducted by feed water from tank 105 having the lowest TDS and the best
ability to re-dissolve
salts and remove buildup. Coating the cyclones with PTFE also contributed to
the best overall
clean cyclones due to its non-stick properties.
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[0215] In cases where the water is flushed in a direction opposite to the
normal flow of
gas through the demister, the flushing generally cannot be done at the same
time as the
demister is operating. Therefore, in these cases flushing would typically be a
periodic function
(e.g. once every 1/2 day).
[0216] On the other hand, in cases where the water is flushed with the
normal flow of
the gas through the demister, the flushing may take place more frequently
(e.g. once every 1/2
hour).
Demister Rotational Configurations
[0217] As noted above, it may be advantageous if the present RVVVS can be
efficiently
use the energy from the heat source to reduce the need for additional energy
input. Because
the available pressure from an engine heat source is limited, it is important
to reduce or
minimize the resistance to air flow through the device. Therefore, it may be
important to ensure
that where a number of cyclone demisters are used in conjunction with each
other that the
rotation of each cyclone is coordinated with the other cyclone demisters.
[0218] Figure 7A and Figure 7B are horizontal cross-sections through the
demisters to
show the two main configurations which may be used where the demisters are
arranged in a
circle. In Figure 7A, all of the demisters are configured to induce the same
direction of rotation
to the gas. This may allow a larger rotation to be set up where the gas
outside the demisters at
the outside of the circle is induced to rotate in one direction, whereas the
gas outside the
demisters at the inside of the circle is induced to rotate in the opposite
direction. Another
advantage of the arrangement of Figure 7A is that all of the demisters may be
identical which
may reduce manufacturing and maintenance and repair costs.
[0219] In Figure 7B, neighbouring demisters are configured to induce
rotational motion
of the opposite orientation. That is each right-handed cyclonic demister will
have neighbours
which are induce left-handed rotation (and vice versa). In this case, the gas
flow between
neighbouring demisters do not form a turbulent boundary because the gas flow
(shown in dotted
arrows) from each is travelling in the same direction.
[0220] It will be appreciated that which of these modes will provide the
least resistance
to airflow may depend on the number of cyclone demisters, the spacing between
the demisters,
the angular velocity induced by each demister, the diameter of each demister,
and so on. The
optimal configuration may be determined using airflow modelling.
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Condenser
[0221] In some embodiments, it may be desirable to condense the water
vapor
generated by the vaporization system within a condenser 113 to provide clean
water 111
(Figure 1G).
[0222] The condenser 113 may comprise a condensing chamber through which
the
water vapor passes, wherein the chamber comprises a heat exchange elements for
cooling the
water vapor. The heat exchange elements may be cooled by flowing raw water
through
channels within the heat exchange elements. This has the advantage that as the
water vapor is
cooled and condensed the raw water within the heat exchange elements is
heated. This means
that when the heated raw water is introduced into the vaporization chamber
10a, vaporization
may be more effective.
Barium Removal
[0223] When concentrating water from producing wells, Barium Chloride may
form and
is know to be soluble and is therefore toxic. In a vaporization and
concentration system such as
the present invention, it may be desirable to remove Barium from the
concentrate by making it
insoluble and therefore benign to the environment. One such known method is to
introduce a
reagent such as sodium sulfate into a solution containing barium chloride,
ideally under heat
and vigorous mixing to facilitate a reaction. Since the air knife, water
injection, vaporization
chamber, combustion gas heat and gas velocity shearing pressure collectively
create the ideal
environment wherein violent and hot mixing occur, one need only add the proper
reagent to
precipitate out a non-soluble and environmentally benign barium sulfate.
[0224] In one embodiment the reagent sodium sulfate is added to the water
flow in the
P1 flow circuit between the optional VOC removal step 126 and concentrator
tank 107. In
another embodiment sodium sulfate is added into the water flow circuit of P2
and injected
directly into the vaporization chamber. In both cases mixing occurs wherein a
sulfide ion from
the sodium sulfate reacts with a barium ion from the barium chloride to form
barium sulfate,
which is highly insoluble. The reagent may be stored in a vessel that is
fluidly connected to
either of P1 or P2 flow circuits. The insoluble and benign barium sulfate may
be removed by
filtration and disposed of in any non-hazardous landfill.
[0225] The cost of removing barium from produced water is thereby
substantially
subsidized by the RVVVS vaporization process. In other words, if one were to
remove barium
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sulfide from produced water by a similar method without a RVVVS 10, there
would be cost
associated with heating and mixing the solution.
Modes of Operation
[0226] Generally, the vaporization process will vaporize the water (e.g.
by evaporation,
boiling or partial boiling) within the raw water but will not evaporate
contaminants within the raw
water if the temperature within exhaust/water contact system is maintained
below the
evaporative temperatures of any contaminants.
[0227] Accordingly, raw water falling to the concentrator tank 107 will
generally be
enriched with contaminants relative to raw water entering the vaporization
chamber 10. As
contaminants within unvaporized raw water will have different densities, they
will have a
tendency to settle towards the bottom of the concentrator tank and/or create
stratification of
contaminants within the concentrator tank. To enable stratification to occur,
raw water being
transferred to the vaporization chamber 10 will generally be drawn from upper
regions of the
concentrator tank but a distance below the surface (Figure 2). Raw water from
a bulk raw water
tank 105 or source will be introduced to the concentrator tank at a generally
mid-height location
and concentrated contaminants will be withdrawn from a lower location of the
concentrator tank.
[0228] The system may be operated to vaporize raw water continuously,
semi-
continuously or in batch depending on particular configurations and operation.
[0229] In a continuous or semi-continuous mode of operation, raw water
from a bulk raw
water tank or source may be continuously or periodically added to the
concentrator tank such
that the water level within the tank remains at a particular level. In this
case, as contaminants
are concentrated and settle within the concentrator tank, periodically, the
concentrated raw
water may be removed through a drain system.
[0230] In a batch mode of operation, a single volume of raw water may be
added to the
tank and the system is operated until a desired concentration/volume of
concentrated raw water
is achieved within the tank whereupon the tank may be emptied before starting
a new batch.
Fluids and Contaminants
[0231] The system is highly effective in handling a variety of waste
fluids that may be
collected at drill rig site or other stranded well site, such as a producing
well, including viscous
drilling fluids that may contain a variety of viscosifying agents. Generally,
it has been observed
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that the effect of passing viscous fluids like polymer water through the
vaporization zone 24a
causes at least partial a breakdown of the hydrocarbon chains of the
viscosifying agents which
then effectively reduces the viscosity of the raw water due to heat and/or
shearing effects within
the system as previously described herein.
[0232] As is commonly known raw water produced in conjunction with oil or
gas
production wells contains volatiles and other organics such as BTEX and F1-F2
chain
hydrocarbons (06-016). It has been observed that the vaporization chamber
system as
described herein provides a means of allowing the absorption of engine exhaust
gas
combustion chemicals from into the raw water concentrate. It has been observed
that a majority
of BTEX (80%+) and a portion F1-F2 hydrocarbons contained within produced
water evaporate
to atmosphere within 1-5 days, typically within 2 days, when the produced
water has been
drawn from below surface and permitted access to standard atmospheric
conditions, including
atmospheric pressure. When considering a method of produced water
vaporization, it is
desirable to limit overall atmospheric discharge or volatile and toxic
chemicals. The present
invention synergistically removes at least a portion of these at least a
portion of these chemicals
from exhaust gas 14a that would otherwise be discharged to atmosphere. When
considering the
entire mass balance of these chemicals in produced water, typical water
transport and injection
methods that discharge exhaust gasses and waste exhaust gasses from engine
sources used
for vaporization and how they are added and subtracted from an environmental
discharge
perspective, it becomes apparent that utilization of engine exhaust gasses in
as described
herein as a means to reduce total volumes of produced water become an
attractive
environmentally subtractive alternative to current management of both produced
water and
exhaust gasses.
[0233] Brine water, whether produced water or created as a drilling fluid,
is another
water that is costly to dispose of and harsh on processing and handling
equipment due to it high
saline content. Due to the system keeping relatively low temperatures,
typically under 100 C, on
all wetted surfaces the current invention becomes an attractive and cost
effective means of
management when compared to alternatives.
[0234] Although the present invention has been described and illustrated
with respect to
preferred embodiments and preferred uses thereof, it is not to be so limited
since modifications
and changes can be made therein which are within the full, intended scope of
the invention as
understood by those skilled in the art.
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