Note: Descriptions are shown in the official language in which they were submitted.
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WASTE GASIFICATION SYSTEM
WITH GAS CONDITIONING
Specification
Gasification has been with us for more than a century, and was actually used
in antiquity
for various purposes including the production of charcoal. Coal gasi~cation
was used for
the lighting of streets at night in the early 20t" century and utilized in
Britain as an energy
source for hundreds of years. We are not inventing gasification. We are
inventing the use of
an energy source and creating a catalyst to use gasification in the most
efficient and
environmentally friendly application. The emphasis in invention of the Natural
State
Reduction System or NSRS is to secure a methodology to dispose of various
waste types
in the most environmentally friendly application possible.
Natural State Reduction System is not an incineration or combustion process.
Incineration
and combustion processes seek to destroy waste by burning it, usually at high
temperatures with some amount of excess air; the ultimate purpose of which is
to burn (for
the purposes of waste reduction) as much waste per unit of time as possible.
Various
"starved air" combusters have been designed in recent years with the primary
focus of
improving air emission quality beyond that achievable with conventional
incineration
methods, but these devices still have the ultimate view of solid waste as a
non usable
resource.
This past view however, misses a critical element in the environmental benefit
of this
process. The NSRS approach to converting solids into a gas described herein
that
municipal and industrial solid wastes (which are routinely buried at
landfills) represent a
significant economic resource in the form of a high Btu value non-fossil fuel
product. The
Btu value from this waste can approach the Btu value of natural gas when the
waste gas is
properly prepared in the NSRS with the residuals economically and safely
retrieved .
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The Environmentally responsible conversion of waste materials, virtual 100%
recycling of
the waste stream, and recovery for remanufacturing of all metals, glass, and
minerals
which compose the waste solids, liquids and sludge exemplifies a safe solution
without
unnecessary, and dangerous sorting machines, or exposure to airborne or other
residual
contaminates.
Other gasification processes that are screw fed, and/or sized for specific
biomasses cannot
accept the variety and sizes of Municipal Solid Waste (MSW) that the NSRS can,
and
require expensive upfront sorting and shredding processes, and they have no
simple
controls over the various resulting compounds and recyclables that allow for a
safe and
continuous mixed waste process.
Typical gasification processes have a high temperature requirement and much
higher
oxygen requirements that lead to all the problems affecting the environment.
The NSRS
system that GWPT has invented with all of the following modifications and
built-in
environmental protections operates within 800 to 1100 degrees F and is oxygen
balanced
in order to eliminate combustion where excess oxygen is required.
Our process in varying degrees is the opposite of incineration and eliminates
all of the
environmental problems that incineration represents, because at no point does
combustion
of the waste occur. The terms of reference of our technology is Natural State
Reduction
whereby we speed up natures' composting process at an accelerated rate.
We are deeply concerned about what landfill represents and the emissions that
are
affecting the global environment. Methane off-gassing from landfill is 26
times the density
of C02 as a greenhouse gas agent. Our technology will help eliminate this
threat. This
technology has been refined with the ultimatum of protecting the environment
while
creating client interest and profit incentive for all parties involved. This
is by far the most
cost effective waste gasification process, and will compete with and better
landfill tipping
fees. This will make a very attractive investment for government and the
corporate
community at well below landfill costs for safe disposal methodology second to
none with
an additional energy profit and recyclable sales incentive. Global warming is
a concern of
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government and corporations alike, and our technology will provide the
solution that landfill
global warming emissions represent.
The technology illustrated allows for unsorted municipal, industrial and
medical wastes, and
hazardous wastes to be co-mingled in any given incoming waste load. Waste is
dumped
directly onto a Waste Chute Collector from the waste carrying vehicle. The
chute provides
multiple advantages over direct dumping or conveyor dumping into vessels: The
chute
allows for complete surveillance of waste via camera, overhead crane removal
of large
steel items or suspect items, PCBs detection, radioactive detection via Geiger
counter and
tilting of waste mass to tumble and reveal previously undetectable items;
waste is dried in
the chute through perforated floor and walls using previously un-captured
system waste
heat; screening options for the chute allow for waste variations such as
municipal solid
waste, tires or dewatered biosolids.
The analysis of the waste batch prior to vessel conversion is essential in
today's volatile
dumping activities that do not normally protect the public from hazardous or
uncontrolled
dumping. The quick detection and removal of unwanted items also preserves the
integrity
of the system and removes the possibility of contamination. A hydraulic pump
supports
both ash doors and the grate doors via a steel vertical tube welded to the top
of the ash
doors. All doors and collection bins are fully automated, and are camera and
electric eye
monitored. This unique design allows for a direct and complete transfer of ash
without
exposing any human operators while employing only a handful of moving parts as
compared to other conveyor type transfers that often seize up due to wear and
tear. The
use of gravity as well to move the incoming waste through to the ash
collection bin
minimizes total energy outputs. The ash and recyclables bin is computer
controlled to move
via electric eyes to its destinations. Its upper resting position will be at
grade level where
the entire bin excluding its wheel mechanisms is loaded directly onto a
transport for
subsequent cement batching of ash and glass and bailing of metals, or stored
in an ash silo
for subsequent retrieval. Depending on the site the raising of the bins to
grade is
accomplished by way of ramp or hydraulic lift.
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BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1, Shown is the process flow diagram for a NSRS scalable municipal
solid waste
gasification system that can have one or many waste conversion cells as
embodied in the
present invention
Figure 2, Shown is the plan view of a 120 tonne per day NSRS municipal solid
waste
gasification system with 4 waste chutes 39, 2 Waste Conversion and Recycling
Vessels
(WCRVs) and four waste chutes and four Silo-vacs 35&37.
Figure 3, Shown is a side view section of a single waste conversion and
recycling cell
(WCRV) showing the relationship of the tipping chute to the WCRV, the concrete
envelope
and the Silo-vacs.
Figure 4 Shows details inside the WCRV with the relationships of the grates
shown in open
and closed position 65 and the key accelerant tubes 27 defined in relation to
the gas jet
flows c&b, and extraction of the raw waste gas flow by arrows e.
Figure 5 Shows details inside the WCRV with the relationships of the grates
shown in open
and closed position 65 and the key accelerant tubes 27 defined in relation to
the ash flow
by arrows d, and material extraction flow by arrow c.
Figure 6 shows an example site elevation transverse to figure 3 indicating the
general
relationships of plant components including the fuel preparation cell, the
fuel consumption
device and boiler.
Figure 7 shows the continuation of the exhaust stream from the boiler through
to the heat
exchangers 68 emissions control 70 and final vent 83.
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WASTE GASIFICATION SYSTEM
WITH GAS CONDITIONING
DETAILED DESCRIPTION OF THE INVENTION
Figure 1 is The System Flow Diagram depicting the general arrangement of the
several
embodiments of the invention, and the direction of solids and gases including
their
temperatures as they are processed through the system. First MSW (Flow Path f)
is loaded
into the waste chute 39 where it is screened for radioactive waste and bulky
items that are
removed via overhead crane 47. The perforated walls14 of the chute allow the
MSW to be
exposed to the hot air (Flow Path a) exiting from the concrete jacket 2 and
optional water
jacket around the hot WCRV while waiting over the 12-14 hours for the
preceding batch to
gasify to reduce the moisture content of the receiving waste from approx. 25%
to 10%.
When the WCRV is ready to receive a charge of waste the chute 39 is tipped
hydraulically
into the open top doors 44 of the WCRV. The combination of vibrating the angle
iron
protectors 42 of the Key Accelerant Tubes 27(KATs) and vibrating the grates 65
in the
bottom of the WCRV ensure there is a uniform distribution of the waste to
allow for even
heating and escape of the raw waste gas (e). When the WCRV 1 is full the load
doors 44
are closed and the ambient air in the vessel is vacuumed out to reduce the
oxygen content
in the vessel to between 5-7%. The main burners 22 and the KATs 27 are then
ignited with
conditioned fuel gas from the previous cycle of the NSRS and/or by
supplemental propane
or methane to raise the temperature to between 800-1100°F. The Key
Accelerant
Balancing System (KABS) achieves precise control of the gasification process
with oxygen
and temperature sensors 59 on the key accelerant balancing tubes 27 reporting
to a
process logic controller (not shown, commonly known) that decides location,
timing and
volume of heat (no direct flame) distribution within the waste charge to
ensure even
conversion of the waste to gas. The raw waste gas is continuously drawn off
via gas
extraction ducts 24 containing gas sensors (not shown, commonly known). The
NSRS will
convert combustible solids, liquids and sludges to a raw waste gas comprised
chiefly of a
heavy, BTU-rich gas vapor of carbon dioxide , carbon monoxide and methane. The
raw
waste gas vapor is pulled through the remainder of the processing system by
the force of
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and induced draft fan, downstream at the far end of the system. It takes
roughly 12 hours
for 60 tonnes of waste to convert to a gas. Within the WCRV the array of tubes
that make
up the KABS deliver air and/or conditioned fuel converted from the waste
and/or natural
gas and/or propane and/or any combination of the preceding as specified by the
computerized process logic controller balancing the substoichiometric oxygen
and
supplemental fuel to monitor and regulate the thermal composition of the waste
batch. A
balanced mass reduction throughout the vessel is achieved by way of injecting
key
accelerants located in low temperature anomalies within the batch or by
completely
starving (0%oxygen) in high temperature anomalies. Precise information on
these
anomalies from the thermocouples and gas sensors of the Key Accelerant
Balancing
System mounted on the Key Accelerant Tubes (KATS) allows both starving and
accelerating different parts of any waste batch in real time greatly
increasing efficiency and
safety and greatly reducing tendencies to stalling and/or smoking, or
conversely
unnecessary ignition. The KATs located strategically amongst the waste batch
insure
maximum reduction and conversion in the shortest amount of time avoiding cool
spots or
hot spots without the need of expensive manual waste mixing, sorting ,sizing
or
pelletization.
When the gas sensors in the extraction ducts 24 sense the reduction of raw
waste
gas from the WCRV (after approx 12-14 hours) the waste charge has had all or
most of its
volatile fractions converted to gas. The Key Accelerant Tubes (KATS) 27 and
the Gas Jets
61 now start injecting cooled, clean, oxygen free exhaust gas into the WCRV to
start
cooling the vessel.
The bottom doors 64 and grates 65 are now super-magnetized by built-in electro
magnets (not shown, commonly known) trapping the magnetic metal fraction of
the debris
and ash, then the grate vibrators (not shown, commonly known) are activated to
separate
the ash fraction (b) by gravity to fall through the grates 65 with the
assistance of the cooled
exhaust gas at 100 deg.F entering both from the key accelerant tubes 27 and
high
pressure jets 61 a, fig. 4 opposite from the lower set of vacuum outlets 61 c,
fig. 5.
This combination of agitation, gas jets and vacuuming removes the ash to the
dedicated
Silo-vacs 37 via vacuum pipes 36. Once all of the ash (b) is removed the upper
set of gas
jets 61, fig. 4 and vacuum outlets 61b, fig. 5 are activated and the vibrating
grates 65
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remove the aluminum and other non-magnetic metals and glass (c) from the WCRV
1 to
Silo-vacs 35 that have beneath them four bins with a movable chute 11 . While
the mixed
aluminum and glass is falling from the silo-vac 35 an eddy current separator
33 (not shown,
commonly known) mounted on the outlet chute forces the aluminum into the first
bin while
the glass falls into the second bin.
The electric current magnetizing the grates 65 is now turned off and the
magnetic metals
on flow path (c) are removed by gas jets 61 and vacuum outlets 61 b to the
dedicated Silo-
vacs 33 and into the third bin via dampers and logic controls. Small ferrous
fractions still
remaining on the bottom ash doors are then vacuumed and jetted (61a) onto flow
path b for
a final evacuation of the WCRV and directed by a duct transfer point 81 to
silovac 35. The
cooled exhaust gas introduced during the removal and vacuuming process has
cooled the
WCRV enough to allow the bottom doors 64 and grates 65 to open and allow the
larger
debris, if any, to fall out into movable bins 52 positioned below. Then the
bottom doors and
all jet and vacuum dampers are shut and the next waste charge (f) is tipped in
to repeat the
cycle.
Raw waste gas (e) produced in the WCRV during the heating phase is
continuously drawn
off via ducts 24 during the 12 to 14 hour cycle of the WCRV. The raw fuel gas
is mixed with
oxygen for conditioning in the secondary fuel preparation cell where a
cyclonic action
separates any particulates entrained in the gas stream. The now oxygenated
conditioned
fuel gas (d) is then combusted either in a boiler or a turbine to produce
electricity. .
Operating multiple WCRVs in parallel with staggered batch times with allow
balancing of
the conditioned fuel gas for delivery to the boiler or turbine. A portion of
the exhaust gas
from the turbine or boiler is then directed to either a heat exchanger (hot
water tank , and
radiant heat ) or through the ground to cool the exhaust then introduced as
make up air
volume during the vacuuming process for the removal of the ash and recyclable
components of the residue in the WCRV. If desired in specific applications the
exhaust gas
can be diverted to greenhouses for both its carbon dioxide fraction (if
sufficiently purified )
and heat value. Optional further processing via membrane filtering and/or lime
filtering
cleans the exhaust stream for further industrial uses or district heating.
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In the configuration of the WCRV illustrated the waste chute tilt 39 includes
a hinged
support beam at the exit side while the opposite waste-loading end is free to
travel 55
degrees off the horizontal to rapidly chute a 30 tonne waste load into the
WCRV. The
hydraulic piston 13 that lifts the free end of the chute box up once the two
end doors are
shut into a 20 degree off-vertical position allows the waste to fall into the
vessel. A
significant attribute of the chute design is the perforated stainless steel
metal floor and
walls that allows both drainage to a drying tank of many types of waste and
direct drying of
the waste mass by way of introducing preheated air from the pump room 54 and
collection
bin chambers 52, and the vessel perimeter plenums 48,10 and/or downstream
preheated
air as desired in specific applications.
This de-saturating of the waste while waiting on the chute for the 12 hour
preceding batch
speeds up the conversion process and gains back valuable BTU energy for
subsequent
use. The 2 induction forced air fans 71 located below the chute's central axis
draws the
hot air from the vessel plenum 73 through the chute sides.
The WCRV, the collection bin chamber, and vertical pump rooms share a 1 m wide
plenum
(not shown) that allows for the recapture of escaping radiant heat from the
system and
allows for a maintenance space for the various exposed exterior elements of
the system.
The outside wall of the envelope is insulated acting as both the structural
containment of
the system and a heat sink that absorbs overflow heat at maximum temperature
times.
This thermal mass provides a balanced supply of hot air for the use of vessel
air and chute
waste drying air using the structure itself to store temperatures that may or
may not be
called for either at times of dry waste in the chute or when no or little
jacket hot air is
available at batch start-up times.
The Waste Conversion and Recycling Vessels 1 can be of any shape and
dimension,
depending on site conditions and the waste volume to be processed. The WCRV
version
illustrated is a rectangular, 12mm thick cold rolled steel box approximately
6m x 6m x 20m.
The inside of this vessel is lined with 250mm of mineral wool, or other
insulating, non-
combustible material. Over this insulation blanket, lining the WCRV interior
is a layer of
304 stainless steel approximately 4 mm thick. The Waste chutes 14 dump
directly into the
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waste conversion vessels each holding from 40 to 60tonnes of waste. For a
double vessel
(240 tonne per day system) as shown in Fig.2, 120 tonnes are processed in
parallel, but
the batch start-up times are staggered between the two vessels to improve
waste gas
balancing. Bulky items, if any, are dropped storage bins below the vessel, at
the end of the
process via large bottom opening doors.
The illustrated version of the WCRV contains Key Accelerant Tubes (KATs) that
are
mounted transversely within the vessel spaced to accept MSW that does not
contain bulky
items ie: stoves, dryers etc. Depending on the size and shape and constituent
waste to be
gasified, other versions of the WCRV can have the KATs mounted on the
longitudinal walls
and/or on a longitudinal spine and /or on a plurality of longitudinal spines
and/or on a
transverse spine or plurality of transverse spines. The optional central
longitudinal spine 84
is configured for a version of the WCRV that has KATs that are mounted on the
longitudinal
walls and the central longitudinal spine and can accept entire uncrushed cars
for the
gasification of their volatile fractions before being crushed and smelted
thereby greatly
reducing the pollutants the smelter discharges.
The Vertical Hydraulic Pump room 54 houses the hydraulic lift pumps that are
fully remotely
controllable. The collection bins are moved forward of the lift to provide
clearance just prior
to activating the pump.
The Waste Fuel Preparation Cell 49 is a sphere, 4m in diameter and made from
hot rolled
steel 6mm thick. It is lined with gunnite applied insulative clay, sufficient
in thickness to
keep the exterior surface temperature of the cell below 200 ° F. The
raw waste gas is
vented from the vessel into this sphere shaped processor, which spins the raw
gas with
compressed air. This process elevates the percentage of oxygen in the finished
gas
product to ambient (~20%). Further, the turbulence in the sphere acts as a
cyclone
separator that causes any fine particulate or heavy metals to fall from
suspension in the
gas. This finished fuel gas is combusted in the primary energy system of the
facility (steam
boiler, hot water heater, refrigeration unit, or other such industrial
processor).
The Waste Fuel Consumption Device embodiment 50 flares the combustible
processed
fuel gas to produce heat for the subject industrial process (hot water heater,
boiler, steam
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turbine, refrigeration unit, etc.) A gas turbine may be used in lieu of hot
water or steam
requirements where only electrical production is desired. The conditioned fuel
gas entering
the Waste Fuel Consumption Device passes though a plenum and is flared in
burners with
little or no supplemental fuel depending on the constituents of the waste
batch that
generated it. The resulting fireball causes a superheated exhaust stream of +/-
1600 ° F
which exits this chamber through a restriction in the opposite end of the unit
where the heat
is exposed to the hot water element of a steam boiler which can send the super
heated
steam to a steam turbine for electrical generation, or in the case of the
illustrated version to
the hot water tank 68 whose heat can be sent to local industrial or
residential users via
radiators 69 further cooling the exhaust to approximately 200 ° F where
it enters the lime
screening device 70.
The Lime Screening Device 70 comprises six lime screens 97 removes the
hydrogen
chloride and sulphur dioxides from the exhaust gas. This proprietary three
tiered flow
dampened device is coupled to a final emission regulator on the vent stack
detecting any
emissions over 25 ppm of hydrogen chloride or sulphur dioxide at which time
one of the
three manifolds 96 open putting into flow an appropriate volume of gas through
the screens
and a screen by-pass. This system preserves the lime applied to the screens
for times of
need only when emission guidelines are encroached upon. In most waste batches
this
should not be necessary. The detectors on the stack can be constructed by
those with
ordinary skill in the art
Optionally (not shown) exhaust now can be used to provide heat and carbon
dioxide to the
plants of a greenhouse operation or piped to a industrial workspace through
radiant heat
tubing Optionally (not shown) a portion of the exhaust can be redirected to a
heat
exchanger or passed through pipes in the ground to be returned by duct to the
WCRV
vessel plenum. The temperature of the exhaust column reaching the induced
draft fan
surge tank 74 is approximately 100° F.
The final exhaust 83 can be vented to the atmosphere or sequestered as desired
.
n
