Note: Descriptions are shown in the official language in which they were submitted.
METHOD AND SYSTEM FOR PROCESSING OILY MIXTURE
BACKGROUND
1. Technical Field
[0001] The present teaching relates to methods, systems, and
programming for oily
mixture processing. Particularly, the present teaching is directed to methods,
systems, and
programming for processing oily mixture with microwave.
2. Discussion of Technical Background
[0002] With the increase in oil exploration, development and
production activities,
more and more oily wastewater and oily sludge are generated, which can cause
serious
environmental pollution. Therefore, it is critical for oil industry to develop
techniques about
pollution control and resource utilization of oily sludge and other oily
mixture.
[0003] Existing methods for processing oily mixture include
concentration and
drying method, boiling method, solvent extraction method, biological method,
and thermal cracking
method.
[0004] Concentration and drying method includes concentrating oily
sludge using
gravity, flotation or centrifugal force. For example, because water is heavier
than oil, water in the
oily sludge may be separated and dried from a lower part of the oily sludge.
This method needs a
long time for processing oily sludge.
[0005] Boiling method includes heating oily sludge to boil the water
in the oily
sludge. Water and hydrocarbons with low boiling points can be steamed out from
the top of a tower
that carries the oily sludge. This method cannot thoroughly process the oily
sludge and cannot
make a good resource utilization of the oily sludge.
[0006] Solvent extraction method mainly refers to using chemical
solvents to extract
crude oil from oily sludge. After preliminary separation, oil and other liquid
fluid flow into an
extraction device to extract crude oil with some chemical solvent. After
extraction of the crude oil,
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the left sludge is dehydrated in a centrifugal dehydration device to generate
dehydrated sludge to be
used as fuel. This method needs a long and complex process.
[0007] Biological method mainly refers to microbial degradation of
oily sludge,
which may convert hydrocarbon organic matter in the oily sludge into carbon
dioxide and water.
This leads to a high cost and a slow processing speed due to degradation.
[0008] Thermal cracking is a simple, thorough method for processing
oily sludge.
Since oily sludge contains crude oil that includes a large percentage of heavy
mineral oil, this
method may be used to crack and condense heavy oil, such that hydrocarbons can
be separated and
recovered. But most existing thermal cracking methods are performed in a
closed system that
cannot heat the oily sludge uniformly and cannot adapt to different feeding
materials.
[0009] Therefore, there is a need to develop techniques to process
oily mixture to
overcome the above drawbacks.
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SUMMARY
[0010] The present teaching relates to methods, systems, and
programming for oily
mixture processing. Particularly, the present teaching is directed to methods,
systems, and
programming for processing oily mixture with microwave.
[0011] In one example, a method for processing oily mixture is
disclosed. The oily
mixture is received and frozen to generate frozen oily mixture. The frozen
oily mixture is broken
into pieces. The pieces are dehydrated in a first heating process to generate
dehydrated pieces. The
dehydrated pieces are cracked in a second heating process.
[0012] In another example, a method for processing oily mixture is
disclosed. The
oily mixture is fed into a first portion of a device. At the first portion of
the device, the oily mixture
is dehydrated with microwave to generate a dehydrated product. The dehydrated
product is
continuously moved from the first portion of the device into a second portion
of the device. At the
second portion of the device, the dehydrated product is cracked with
microwave.
[0013] In a different example, a system for processing oily mixture
is disclosed. The
system comprises: a material feeder configured for receiving and freezing the
oily mixture to
generate frozen oily mixture, and breaking the frozen oily mixture into
pieces; an oil mixture
dehydrator configured for dehydrating the pieces in a first heating process to
generate dehydrated
pieces; and an oily mixture cracker configured for cracking the dehydrated
pieces in a second
heating process.
[0014] Additional novel features will be set forth in part in the
description which
follows, and in part will become apparent to those skilled in the art upon
examination of the
following and the accompanying drawings or may be learned by production or
operation of the
examples. The novel features of the present teachings may be realized and
attained by practice or
use of various aspects of the methodologies, instrumentalities and
combinations set forth in the
detailed examples discussed below.
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BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The methods, systems, and/or programming described herein are
further
described in terms of exemplary embodiments. These exemplary embodiments are
described in
detail with reference to the drawings. These embodiments are non-limiting
exemplary
embodiments, in which like reference numerals represent similar structures
throughout the several
views of the drawings, and wherein:
[0016] FIG. 1 shows an exemplary process for thermal cracking oily
mixture,
according to an embodiment of the present teaching;
[0017] FIG. 2 illustrates a process flow for thermal cracking oily
mixture with
microwave, according to an embodiment of the present teaching;
[0018] FIG. 3 illustrates a sectional view of a feeder of an
exemplary thermal
cracking device, according to an embodiment of the present teaching;
[0019] FIG. 4 illustrates a lateral view of an exemplary thermal
cracking furnace,
according to an embodiment of the present teaching;
[0020] FIG. 5 shows an exemplary diagram illustrating a thermal
cracking device,
according to an embodiment of the present teaching;
[0021] FIG. 6 is a flowchart of an exemplary process of thermal
cracking oily
mixture with microwave, according to an embodiment of the present teaching;
[0022] FIG. 7 is a flowchart of an exemplary process for extracting
and processing
steam generated from dehydration, according to an embodiment of the present
teaching;
[0023] FIG. 8 is a flowchart of an exemplary process for extracting
and processing
cracked gas generated from thermal cracking, according to an embodiment of the
present teaching;
[0024] FIG. 9 illustrates different views of a drill in a feeder of
an exemplary
thermal cracking device, according to an embodiment of the present teaching;
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[0025] FIG. 10 shows an exemplary application environment for thermal
cracking
oily mixture with microwave, according to an embodiment of the present
teaching;
[0026] FIG. 11 shows another exemplary application environment for
thermal
cracking oily mixture with microwave, according to an embodiment of the
present teaching;
[0027] FIG. 12 shows yet another exemplary application environment
for thermal
cracking oily mixture with microwave, according to an embodiment of the
present teaching; and
[0028] FIG. 13 shows still another exemplary application environment
for thermal
cracking oily mixture with microwave, according to an embodiment of the
present teaching.
DETAILED DESCRIPTION
[0029] In the following detailed description, numerous specific
details are set forth
by way of examples in order to provide a thorough understanding of the
relevant teachings.
However, it should be apparent to those skilled in the art that the present
teachings may be practiced
without such details. In other instances, well known methods, procedures,
systems, components,
and/or circuitry have been described at a relatively high-level, without
detail, in order to avoid
unnecessarily obscuring aspects of the present teachings.
[0030] The present disclosure describes method and system of
processing oily
mixture, e.g. oil sludge, oil sands, oil wastewater, etc., with microwave.
Oily sludge is oily waste
that may be produced during operations of oil extraction, oil transportation,
oil refining and oily
sewage treatment. Oily sludge usually has a bulky volume, a high calorific
value, high water
content, and complicated composition. Oily sludge may have harmful components
most of which
exceed emission standards. These characteristics may make it difficult to
process oily sludge.
[0031] Disclosed herein are methods and a system for processing oily
sludge based
on thermal cracking. The system may thermally crack oily sludge in a sealed
condition to produce
gases and residues that may be condensed and recovered. The same system can
process solid oily
mixture and liquid oily mixture at the same time.
Date Recue/Date Received 2021-04-22
[0032] An oily mixture may include oily sludge that is solid waste
with a rich
component of oil. Oily sludge is sludge mainly comprising clay particles,
organic matter, floc,
microorganisms and their metabolites, minerals, etc. Oily sludge usually comes
from oil sands and
sludge generated in the process of oil exploration, oil development and
production in oil and
chemical industry. Oily sludge may be generated in a large volume. Oily sludge
may contain a
large percentage of oil that comprises a rich component of heavy oil. Oily
sludge may be in form of
sand-based lump sludge and water-based viscous sludge. An oily mixture may
also include oily
wastewater containing crude oil and other impurities. Oily wastewater may be
generated in the
process of oil and gas production.
[0033] According to an embodiment of the present teaching, the system
includes a
feeder that can freeze the oily mixture and break the frozen oily mixture into
pieces, which can feed
the system with even amount of pieces along the time. Accordingly, the oily
mixture feed can be
processed without classification based on its components. Regardless the
components in the oily
mixture, whether the oily mixture includes sand-based lump sludge, oil-water
viscous sludge, or
oily wastewater, the oily mixture can be directly processed to achieve a
universal feed.
[0034] According to an embodiment of the present teaching, the system
utilizes
microwave to heat oily sludge during processing. Microwave can be used to
achieve a fast, unifoi iii
heating, with characteristics of anti-enzyme, sterilization, automatic
controlling, etc. Microwave
heating is energy efficient, safe and sound. Microwave heating technology has
benefits in
applications of drying, breaking, sintering, induced catalysis, especially
catalysis of chemical
reactions. Applying microwave to dry and heat oily mixture can effectively
prevent coking
phenomenon from happening during the process of thermal cracking the oily
mixture.
[0035] After the fed oily mixture is frozen and cut into pieces, the
system may move
the pieces into a furnace for microwave heating. According to an embodiment of
the present
teaching, the microwave heating is a two-stage process including an upstream
drying stage and a
downstream thermal cracking stage. During the upstream drying stage, most
water component in
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the oily mixture may evaporate and some light-weight hydrocarbon in the oily
mixture can also
evaporate to be extracted for recovery. During the downstream thermal cracking
stage, the system
may thermally crack the heavy-weight oil component in the oily mixture to
generate light-weight
hydrocarbon that may also evaporate to be extracted for recovery. The two
stages may be
performed in the furnace's two portions that are connected with a conveyor
belt, to achieve a
continuous processing of oily mixture.
[0036] According to an embodiment of the present teaching, the system
can recover
more than 82% of crude oil in the oily mixture, and achieve a high safe
disposal rate and a high
resource recovery rate. Oil content in the solid residue after the processing
may be less than 0.3%.
For dehydrated oily sludge with more than 20% oil content, the system may
achieve a net energy
output, such that economic efficiency is greater than the cost of processing.
[0037] In addition, the system can utilize a simple equipment to
achieve reliable
operation and high energy recovery, with no secondary pollution, which leads
to environmental and
economic benefits and provides a new way for making oily sludge harmless and
for resource
utilization. Furthermore, the system in the present teaching does not add
anything into the oily
mixture being processed.
[0038] Additional novel features will be set forth in part in the
description which
follows, and in part will become apparent to those skilled in the art upon
examination of the
following and the accompanying drawings or may be learned by production or
operation of the
examples. The novel features of the present teachings may be realized and
attained by practice or
use of various aspects of the methodologies, instrumentalities and
combinations set forth in the
detailed examples discussed below.
[0039] FIG. 1 shows an exemplary process 100 for thermal cracking
oily mixture,
according to an embodiment of the present teaching. At material feeding 102,
material is fed into a
system for processing The material may be any oily mixture including sand-
based lump sludge,
oil-water viscous sludge, oily wastewater, or any combination of them. At
material feeding 102, the
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system can freeze the fed material, e.g. using liquid nitrogen, and break the
frozen material into
pieces.
[0040] At microwave-based dehydration 104, the system may dehydrate
the pieces
by exposing the pieces to microwave to generate dehydrated pieces. This may be
performed in a
first portion of a microwave furnace that can heat material inside with
controlled microwave power.
The water component in the pieces can evaporate and be recovered for reuse. In
one example, at
microwave-based dehydration 104, the system can also extract light-weight
hydrocarbon from the
pieces with microwave heating, and recover the extracted light-weight
hydrocarbon for reuse. The
microwave-based dehydration 104 may be performed in an anaerobic environment.
The
dehydration described here may refer to removing moisture in the oily mixture
pieces, such that it
does not require removing all water in the pieces.
[0041] At microwave-based cracking 106, the system can heat oily
mixture quickly
to higher than 400 C, which may include stages of hydrocarbon evaporation,
thermal cracking, and
microwave burning. When the temperature is higher than 200 C, light-weight
hydrocarbon in the
oily mixture pieces continues to evaporate and may be thermal cracked into
gas, and oil production
rate increases with increasing temperature. When the temperature is at 460 C
¨ 490 C, the liquid-
phase oil yield and conversion rate increase with increasing temperature; and
the liquid-phase oil
yield may decline when temperature continues to increase further. When the
temperature reaches
about 450 C, the system may crack heavy-weight oil components in the oily
mixture pieces to form
light-weight oil for recovery. When the temperature reaches about 520 C, the
system may crack
oil components in the oily mixture pieces to form lighter oil and gaseous
hydrocarbons, where the
amount of non-condensable gases may increase. When the temperature is higher
than 520 C, the
system may continue bum the oily mixture pieces with microwave to extract oil
and generate gas
and residues.
[0042] The microwave-based cracking 106 may be performed in an
anaerobic
environment in a second portion of the microwave furnace. The first portion of
the furnace and the
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second portion of the device may be separated by a gas curtain such that
temperature in the first
portion and temperature in the second portion can be different. The gas
curtain may comprise
nitrogen gas and/or steam.
[0043] At residue processing 108, the system may process the steam
generated from
the microwave-based dehydration 104 and the cracked gas and solid residues
generated from the
microwave-based cracking 106. For example, the system may collect the steam
generated from the
microwave-based dehydration 104 and use a part of the collected steam as a
source for the gas
curtain separating the two portions of the microwave furnace. The system may
also use another
part of the collected steam as spraying water to cool the cracked sludge
residue, after condensing
the part of collected steam.
[0044] The system may extract oil, wastewater, and non-condensable
gas from the
cracked gas generated from the microwave-based cracking 106. The system may
send the extracted
oil for further separation and refining. The system may send the wastewater
for further treatment or
recovery. The system may send the non-condensable gas for further treatment or
emit the non-
condensable gas if it is harmless. For the solid residues generated from the
microwave-based
cracking 106, they may be safe and ready for emission since their oil content
can be very low, e.g.
less than 0.3%, after the processing
[0045] FIG. 2 illustrates an exemplary detailed process flow for
thermal cracking
oily mixture with microwave, according to an embodiment of the present
teaching. According to
the example disclosed in FIG. 2, the system for thermal cracking oily mixture
includes a feeder 201,
a microwave thermal cracking furnace 202, a bag filter 203, a compressor 204,
a steam heat
exchanger 205, a cracked gas condenser 206, a three-phase separator 207, a
blower 208, a steam
condenser 209, a cooling water nozzle 210, a sludge tank 211, a drying furnace
chamber 212, a
thermal cracking furnace chamber 213, a conveyor belt 214, Gas curtains 215,
216, 217, exhaust
ports 218, 219, a drill 220, a gas chamber 221, an oil chamber 222, and a
water chamber 223.
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[0046] As shown in FIG 2, oily mixture is first put into the feeder
201 At the
feeder 201, the oily mixture is frozen to become solid or a non-flowing state.
In general, the oily
mixture may be frozen to any state that is hard enough to be broken into
pieces. For example, the
feeder 201 may freeze the oily mixture in a cooling pipe with liquid nitrogen.
The frozen oily
mixture is then broken into pieces, e.g. by the drill 220 at the feeder 201
The drill 220 can drill and
cut the frozen oily mixture into pieces that have a more or less uniform size,
such that the pieces
can be evenly heated later during microwave heating. Each piece may be small
enough such that it
can be heated evenly inside and outside with microwave.
[0047] The pieces can then be put at the feeding end of a microwave
thermal
cracking furnace 202. The microwave thermal cracking furnace 202 may include
two portions: a
drying furnace chamber 212 and a thermal cracking furnace chamber 213. A
conveyor belt 214 can
convey the pieces into the two chambers continuously, to provide a continuous
feeding of oily
mixture pieces.
[0048] The microwave thermal cracking furnace 202 can heat the oily
mixture
pieces with microwave, utilizing microwave's thermal conductivity effect. The
microwave thermal
cracking furnace 202 may bear the conveyor belt 214, e.g. a stainless steel
conveyor belt for
conveying the oily mixture pieces. The thermal cracking process in the
microwave thermal
cracking furnace 202 includes two stages: an upstream drying stage and a
downstream thermal
cracking stage. While the conveyor belt 214 conveys an oily mixture piece into
the drying furnace
chamber 212, the piece is dried and dehydrated at the upstream drying stage.
While the conveyor
belt 214 conveys the oily mixture piece into the thermal cracking furnace
chamber 213, the piece is
thermal cracked at the downstream thermal cracking stage. The conveyor belt
214 continuously
conveys oily mixture pieces into the two chambers, to provide a continuous
processing of oily
mixture pieces.
[0049] Gas curtains 215 and 216 are respectively located at the two
ends of the
microwave thermal cracking furnace 202, to seal the microwave thermal cracking
furnace 202 with
Date Recue/Date Received 2021-04-22
gas curtains. The drying furnace chamber 212 and the thermal cracking furnace
chamber 213 are
also separated by a Gas curtain 217 that is provided at the boundary of the
two chambers to isolate
gas on the two sides of the Gas curtain 217. As such, the temperature in the
two chambers can be
different; and the temperature in the microwave thermal cracking furnace 202
can be different from
the temperature outside the microwave thermal cracking furnace 202 The gas
source for each gas
curtain may be either nitrogen gas generated by a nitrogen maker or steam
generated during the
upstream drying stage. For example, when the system just starts, nitrogen gas
generated by a
nitrogen maker can be used as gas source for the gas curtains. After the
system runs for a while, the
steam generated during the upstream drying stage can be used as gas source for
the gas curtains.
[0050] At the upstream drying stage in the drying furnace chamber
212, the frozen
oily mixture pieces are heated to more than 100 C, e.g. 120 C, such that
water and/or light-weight
hydrocarbon in the oily mixture pieces can evaporate. This stage may dehydrate
the oily mixture by
removing about 500/ of the water in the oily mixture pieces. The steam or
water vapor from
evaporation can be pumped out by the blower 208 via the exhaust port 218 at
the drying furnace
chamber 212. A part of the pumped steam may be heated by the steam heat
exchanger 205 and
used as a source of the gas curtains 215, 216, 217. Another part of the pumped
steam can be
condensed by the steam condenser 209 to serve as spraying water to cool the
cracked sludge residue
in the sludge tank 211, via the cooling water nozzle 210. The temperature in
the drying furnace
chamber 212 is usually below 205 C.
[0051] According to one embodiment, after the blower 208 pumps out
the steam
generated at the upstream drying stage via the exhaust port 218, the steam
pipeline is divided into
two lines, one going to the steam heat exchanger 205 and the other going to
the steam condenser
209. The division ratio of the steam in the two lines can be controlled
proportionally by a pipeline
valve. The division ratio may be determined based on factors including
processing capacity, oily
mixture's moisture content, needed gas amount for the gas curtains, etc. The
steam part going to
the steam heat exchanger 205 can exchange heat with the cracked gas generated
at the downstream
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thermal cracking stage, such that the temperature of the steam increases and
the temperature of the
cracked gas decreases. The quality of the steam may be improved after the
steam is heated at the
steam heat exchanger 205, such that the heated steam can be used as a source
for the gas curtains
215, 216, 217. The steam part going to the steam condenser 209 can be
condensed and then go to
the cooling water nozzle 210 to cool the cracked sludge residue in the sludge
tank 211 as cooling
spraying water.
[0052] According to another embodiment, since light-weight
hydrocarbon in the oily
mixture pieces also evaporates at the upstream drying stage, the blower 208
pumps out both the
steam and the light-weight hydrocarbon gas via the exhaust port 218. The
pumped water steam and
light-weight hydrocarbon gas may be condensed and separated by an oil/water
separator, e.g. a
three-phase separator, to separate the light-weight hydrocarbon and the water
steam. The light-
weight hydrocarbon can then be collected. The separated water steam can then
be divided into two
lines The steam in one line goes to the steam heat exchanger 205 for heat
exchanging with the
cracked gas generated at the downstream thermal cracking stage, to be heated
up for use as a source
for the gas curtains 215, 216, 217. The steam in the other line goes to the
steam condenser 209 to
be condensed and then goes to the cooling water nozzle 210 to cool the cracked
sludge residue in
the sludge tank 211 as cooling spraying water.
[0053] At the downstream thermal cracking stage in the thermal
cracking furnace
chamber 213, the oily mixture pieces may be heated with microwave quickly to a
temperature
higher than 400 C, e.g. 560 C. This may include stages of hydrocarbon
evaporation, thermal
cracking, and microwave burning. When the temperature of the oily mixture
pieces is higher than
200 C, light-weight hydrocarbon in the oily mixture pieces continues to
evaporate and may be
thermal cracked into gas, and oil production rate increases with increasing
temperature. The
thermal cracking furnace chamber 213 can use microwave to quickly increase the
temperature of
the oily mixture pieces from lower than 200 C to higher than 400 C, which
effectively prevents
generation of toxic substances like dioxin. When the temperature of the oily
mixture pieces is at
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460 C ¨ 490 C, the liquid-phase oil yield and conversion rate increase with
increasing
temperature. The liquid-phase oil yield may decline when the temperature of
the oily mixture
pieces continues to increase further. When the temperature reaches about 450
C, the thermal
cracking furnace chamber 213 may crack heavy-weight oil components in the oily
mixture pieces to
form light-weight oil for recovery. When the temperature reaches about 520 C,
the thermal
cracking furnace chamber 213 may crack oil components in the oily mixture
pieces further to form
lighter oil and gaseous hydrocarbons, where the amount of non-condensable
gases may increase.
When the temperature is higher than 520 C, the thermal cracking furnace
chamber 213 may
continue burn the oily mixture pieces with microwave to extract oil and
generate gas and residues.
[0054] According to one embodiment, the cracked gas generated at the
downstream
thermal cracking stage may be withdrawn from the exhaust port 219 at the
thermal cracking furnace
chamber 213. The cracked gas may comprise light-weight oil components and
water steam. The
cracked gas may enter the bag filter 203 to filter out dust or soot in the
cracked gas. The filtered
cracked gas then goes through the compressor 204 to booster its pressure for
providing transport
power. The cracked gas is then transported to the steam heat exchanger 205 to
exchange heat with
the steam generated at the upstream drying stage, to reduce temperature of the
cracked gas and
increase temperature of the steam.
[0055] In one example, the steam heat exchanger 205 is a shell and
tube heat
exchanger that has tube-side import and export and shell-side import and
export. At the steam heat
exchanger 205, the cracked gas goes through the shell, entering the steam heat
exchanger 205 via
the shell-side import and exiting the steam heat exchanger 205 via the shell-
side export after heat
exchanging. The steam goes through the tube, entering the steam heat exchanger
205 via the tube-
side import and exiting the steam heat exchanger 205 via the tube-side export
after heat exchanging.
[0056] The cracked gas exiting the steam heat exchanger 205 may be
transported via
pipeline into the cracked gas condenser 206 to be further cooled and condensed
to form a liquid/gas
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mixture. The liquid/gas mixture may include both light-weight oil and water.
In one example, the
cracked gas condenser 206 may cool the cracked gas with cold water.
[0057] Then, the liquid/gas mixture enters the three-phase separator
207 for
separation. Making use of gravity, the three-phase separator 207 can separate
the liquid/gas mixture
into three-phases: gas, oil, and water. The three-phase separator 207 in this
example includes a gas
chamber 221, an oil chamber 222, and a water chamber 223. Oil in the
liquid/gas mixture goes into
the oil chamber 222 and is discharged from an oil export at the bottom of the
oil chamber 222. The
system may send the discharged oil for further separation and refining.
Wastewater in the
liquid/gas mixture goes into the water chamber 223 and is discharged from a
water outlet at the
bottom of the water chamber 223. The system may send the discharged wastewater
for further
treatment or recovery. Non-condensable gas left in the liquid/gas mixture goes
into the gas
chamber 221 and is withdrawn from the top of the gas chamber 221. The system
may send the non-
condensable gas for further treatment or emit the non-condensable gas if it is
already harmless.
[0058] At the downstream thermal cracking stage in the thermal
cracking furnace
chamber 213, the oily mixture pieces are thermal cracked to generate the
cracked gas and leave
sludge residues. The sludge residues generated from the downstream thermal
cracking stage may
be conveyed by the conveyor belt 214 to the sludge tank 211. After being
cooled by the spraying
water from the cooling water nozzle 210, the sludge residues in the sludge
tank 211 can be
transported out, because they are safe and ready for emission since their oil
content can be very low,
e.g. less than 0.3%, after the processing.
[0059] The microwave-based thermal cracking technology is feasible
for processing
oily mixture. The thermal cracking process is safe to environment. The gas
generated from the
thermal cracking process contains a large amount of combustible gas that can
be used as a clean
fuel gas. The oil generated from the thermal cracking process mainly contains
light fuel oil, with
gasoline and diesel components counting up to more than 80%. Under suitable
conditions, the oil
ratio in the sludge residue can be as low as 0.005%, meeting emission
requirements. After some
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classification process performed on the sludge residue, people may get some
high value-added
activated carbon, which provides a deep resource utilization of the oily
mixture.
[0060] FIG. 3 illustrates a sectional view of a feeder of an
exemplary thermal
cracking device, according to an embodiment of the present teaching. FIG. 3
shows an exemplary
structure of a feeder, e.g the feeder 201 in FIG. 2. As shown in ....... FIG.
3, the feeder in this example
includes a feeding funnel 301, a feed entrance 302, rotary pistons 303, a
cooling tube 304, a cutting
drill 305, a feed exit 306, a turntable 307, a hydraulic pump 308, a feed
moving plate 309, and
guideways 310.
[0061] According to an embodiment of the present teaching, the
feeding material
can be put into the feeding funnel 301 directly, without need of material
classification and
regardless whether the feeding material includes sand-based lump sludge, water-
based viscous
sludge, oil sands, and/or oily wastewater. The feed moving plate 309 in this
example may then
move the feeding material to the feed entrance 302 which is the entrance to
the cooling tube 304.
The rotary pistons 303 in this example may help to squeeze the material and
push it through the
feed entrance 302 and into the cooling tube 304. The rotary pistons 303 may
squeeze and push
material in a quantitative way. Each time when the turntable 307 is turned,
one of the rotary pistons
303 may be guided by a corresponding guideway 310 to be in front of the
material at the feed
entrance 302. The piston may squeeze and push a fixed quantity of material
into the cooling tube
304 for freezing.
[0062] The cooling tube 304 in this example is a double-layer tube
comprising an
outer-layer tube and an inner-layer tube, where the outer-layer tube is
arranged at the outer part of
the inner-layer tube. The material is pushed into the inner-layer tube, while
the outer-layer tube is
filled with cooling material, e.g. liquid nitrogen. When the material is in
the inner-layer tube, the
material can be cooled down and frozen quickly by the cooling material in the
outer-layer tube,
such that the material will be in a columnar frozen state after being frozen
at the cooling tube 304.
Date Recue/Date Received 2021-04-22
[0063] As the rotary pistons 303 forcibly push newly fed oily mixture
into the
cooling tube 304, the rotary pistons 303 also push the columnar frozen oily
mixture in the cooling
tube 304 toward the feed exit 306. While the columnar frozen oily mixture in
the cooling tube 304
is pushed to the feed exit 306, the columnar frozen oily mixture is under
reverse pressure from the
cutting drill 305 at the feed exit 306. The cutting drill 305 in this example
is pushed by the
hydraulic pump 308 to generate pressure against the push from the rotary
pistons 303 and to break
and cut part of the columnar frozen oily mixture at the feed exit 306 into
pieces. FIG. 9 illustrates
different views (a plan view 902, a bottom view 904, and a lateral view 906)
of a drill, e.g. the
cutting drill 305 in a feeder of an exemplary thermal cracking device,
according to an embodiment
of the present teaching.
[0064] According to an embodiment of the present teaching, the
cutting drill 305 can
drill and cut the frozen oily mixture into pieces that have a more or less
uniform size, such that the
pieces can be evenly heated later during microwave heating. Each piece may be
small enough such
that it can be heated evenly inside and outside with microwave. For example,
for each of the pieces,
the dimension along any direction is less than 40 centimeter. In another
example, for each of the
pieces, the dimension along any direction is less than 35 centimeter.
[0065] The frozen oily mixture pieces at the feed exit 306 can be
conveyed into a
microwave room by a conveyor belt 311. The microwave room may be the drying
furnace chamber
212 shown in FIG. 2 for heating the pieces with microwave. The pieces may then
be dehydrated
and thermal cracked as discussed above regarding FIG. 2.
[0066] FIG. 4 illustrates a lateral view of an exemplary thermal
cracking furnace, e.g
the microwave thermal cracking furnace 202 in FIG. 2, according to an
embodiment of the present
teaching. As shown in FIG. 4, the microwave thermal cracking furnace 202 in
this example
includes two microwave suppressors 403, 412, three Gas curtains 404, 408, 411,
a plurality of
microwave sources 406, a plurality of exhaust ports 407, and a microwave
furnace chamber 410.
16
Date Recue/Date Received 2021-04-22
[0067] FIG. 4 also shows a belt conveyor 401 that comprises a
conveyor belt 409.
In one embodiment, the conveyor belt 409 is a stainless steel conveyor belt
whose upper belt goes
through the microwave thermal cracking furnace 202. The stainless steel
conveyor belt may be
connected to a tensioning device and a driving device. FIG. 4 also shows a
plurality of supporting
stands 405 that support both the belt conveyor 401 and the microwave thermal
cracking furnace 202
The plurality of stands 405 may be located between the tensioning device and
the driving device.
[0068] During the process of oily mixture, the oily mixture is frozen
and cut into
pieces at the feeder as described above. The frozen oily mixture pieces are
continuously placed at a
feeding end 402 on the conveyor belt 409, such that the frozen oily mixture
pieces are transported
into the microwave furnace chamber 410 via the conveyor belt 409. Both sides
of the microwave
furnace chamber 410 are sealed with the gas curtains 404, 411, which may
create an anaerobic
environment in the microwave furnace chamber 410.
[0069] As described above, the microwave furnace chamber 410 may be
divided
into two parts: a drying furnace chamber and a thermal cracking furnace
chamber. The gas curtain
408 is set between the drying furnace chamber and the thermal cracking furnace
chamber to
separate the gas in the two parts, such that the temperatures of the two
chambers are different. The
temperature of oily mixture pieces may increase sharply after the oily mixture
pieces are moved
from the drying furnace chamber into the thermal cracking furnace chamber.
[0070] Both the drying furnace chamber and the thermal cracking
furnace chamber
have exhaust ports 407 for withdrawing water steam and/or cracked gas. As
discussed above, the
water steam generated in the drying furnace chamber may be heated for
providing gas to the gas
curtains or be condensed to spraying water for cooling sludge residues. The
cracked gas generated
in the thermal cracking furnace chamber may be processed to extract gas, oil,
and water separately.
[0071] Both the drying furnace chamber and the thermal cracking
furnace chamber
include the microwave sources 406 for generating microwave to heat the oily
mixture pieces. The
two microwave suppressors 403, 412 are located at the two ends of the
microwave thermal cracking
17
Date Recue/Date Received 2021-04-22
furnace 202 respectively, to ensure there is no microwave leaking outside the
microwave thermal
cracking furnace 202 when microwave is being used in the microwave thermal
cracking furnace
202.
[0072] According to one embodiment of the present teaching, the oily
mixture
pieces are heated to 120 C in the drying furnace chamber, to be dried and
dehydrated The
dehydrated oily mixture pieces are conveyed into the thermal cracking furnace
chamber by the
conveyor belt 409. Hydrocarbon distillation and thermal cracking may happen in
the thermal
cracking furnace chamber. Low molecular weight organic matters are first
distilled into gas to be
discharged. Then, heavy hydrocarbons are cracked to produce light-weight
components to be
discharged through the exhaust ports 407. Temperature in each chamber may be
controlled by a
PLC (Programmable Logic Controller) which includes configurable parameters
like heating rate,
settling time, etc.
[0073] The system may perform subsequent processing for sludge
residues
generated by the microwave theimal cracking furnace 202. For example, the
system can perform
grading and classification for the sludge residues, with techniques for safe
disposal, to achieve
completely harmless residues with a fully conversion to resource.
[0074] FIG. 5 shows an exemplary diagram illustrating a thermal
cracking device
500, according to an embodiment of the present teaching. As shown in FIG. 5,
the thermal cracking
device 500 in this example includes a material feeder 502, an oily mixture
dehydrator 504, an oily
mixture cracker 506, and a residue processer 508.
[0075] The material feeder 502 in this example receives feeding
material for
processing. The material may be any oily mixture including sand-based lump
sludge, oil-water
viscous sludge, oily wastewater, or any combination of them. The material
feeder 502 can freeze
the material, e.g. using liquid nitrogen, and break the frozen material into
pieces. The material
feeder 502 may send the pieces into the oily mixture dehydrator 504, e.g. via
a conveyor belt.
18
Date Recue/Date Received 2021-04-22
[0076] The oily mixture dehydrator 504 in this example may dehydrate
the pieces by
exposing the pieces to microwave to generate dehydrated pieces, e.g. in an
anaerobic environment.
As discussed above, the oily mixture dehydrator 504 may be a first portion of
a microwave furnace
that can heat material inside with controlled microwave power. The water
component in the pieces
can evaporate and be recovered for reuse. The oily mixture dehydrator 504 may
also extract light-
weight hydrocarbon from the pieces with microwave heating. The oily mixture
dehydrator 504 may
send the dehydrated pieces into the oily mixture cracker 506, e.g. via the
conveyor belt. The oily
mixture dehydrator 504 may also send water and light-weight hydrocarbon vapors
to the residue
processer 508 for processing.
[0077] The oily mixture cracker 506 in this example may heat the
dehydrated pieces
quickly to higher than 400 C with microwave, e.g. in an anaerobic
environment. When the
temperature is higher than 200 C, light-weight hydrocarbon in the oily
mixture pieces continues to
evaporate and may be thermal cracked into gas, and oil production rate
increases with increasing
temperature. When the temperature is at 460 C ¨ 490 C, the liquid-phase oil
yield and conversion
rate increase with increasing temperature; and the liquid-phase oil yield may
decline when
temperature continues to increase further. When the temperature reaches about
450 C, the oily
mixture cracker 506 may crack heavy-weight oil components in the oily mixture
pieces to form
light-weight oil for recovery. When the temperature reaches about 520 C, the
oily mixture cracker
506 may crack oil components in the oily mixture pieces to form lighter oil
and gaseous
hydrocarbons, where the amount of non-condensable gases may increase. When the
temperature is
higher than 520 C, the oily mixture cracker 506 may continue burn the oily
mixture pieces with
microwave to extract oil and generate gas and residues.
[0078] As discussed above, the oily mixture cracker 506 may be a
second portion of
the microwave furnace. The oily mixture dehydrator 504 and the oily mixture
cracker 506 may be
separated by a gas curtain such that temperature in the oily mixture
dehydrator 504 and temperature
in the oily mixture cracker 506 can be different. The gas curtain may comprise
nitrogen gas and/or
19
Date Recue/Date Received 2021-04-22
steam. The oily mixture cracker 506 may generate and send cracked gas and
sludge residues to the
residue processer 508 for processing.
[0079] The residue processer 508 in this example may process the
steam generated
at the oily mixture dehydrator 504 and the cracked gas and sludge residues
generated at the oily
mixture cracker 506. For example, the residue processer 508 may collect the
steam generated from
the oily mixture dehydrator 504 and use a part of the collected steam as a
source for the gas curtain
separating the two portions of the microwave furnace. The residue processer
508 may also use
another part of the collected steam as spraying water to cool the sludge
residue generated by the
oily mixture cracker 506, after condensing the part of collected steam.
[0080] The residue processer 508 may extract oil, wastewater, and non-
condensable
gas from the cracked gas generated from the oily mixture cracker 506. The
residue processer 508
may send the extracted oil for further separation and refining. The residue
processer 508 may send
the wastewater for further treatment or recovery. The residue processer 508
may send the non-
condensable gas for further treatment or emit the non-condensable gas if it is
harmless. For the
sludge residues generated from the oily mixture cracker 506, they may be safe
and ready for
emission since their oil content can be very low, e.g. less than 0.3%, after
the processing.
[0081] In one embodiment, the material feeder 502 may be implemented
as the
feeder shown in FIG. 2 or FIG. 3. The oily mixture dehydrator 504 may be
implemented as the
drying furnace chamber 212 shown in FIG. 2. The oily mixture cracker 506 may
be implemented
as the thermal cracking furnace chamber 213 shown in FIG. 2. The residue
processer 508 may be
implemented as the condensers, heat exchanger, three-phase separator, and
other processing devices
shown in FIG. 2. It can be understood that while the thermal cracking device
500 may be
implemented as shown in FIGS. 2-4 in accordance with one embodiment, the
thermal cracking
device 500 may also be implemented with other structures in accordance with
other embodiments.
[0082] In other embodiments, the material feeder 502 may be
implemented as a
screw feeder that comprises a driving means, a charging port, a spindle,
spiral blades, and a
Date Recue/Date Received 2021-04-22
discharging port. A power-output end of the driving means may be connected to
the spindle. The
spindle may be configured inside a conveying channel. The screw blades may be
fixed onto the
spindle. The charging port and the discharging port are connected at the two
ends of the conveying
channel.
[0083] In other embodiments, the oily mixture dehydrator 504 and the
oily mixture
cracker 506 may be implemented as a rotary furnace that can heat the oily
mixture by burning fuel
or by electric heating. In other embodiments, the oily mixture dehydrator 504
and the oily mixture
cracker 506 may be implemented as a circulating fluidized bed furnace that can
heat flowing oily
mixture by burning fuel or by electric heating.
[0084] In other embodiments, the residue processer 508 may be
implemented as a
collection system that includes: an oil and gas collector configured outside a
conveying channel;
and a slag collector connected to the discharging port of the conveying
channel.
[0085] FIG. 6 is a flowchart of an exemplary process of thermal
cracking oily
mixture with microwave, according to an embodiment of the present teaching. At
602, a material
feeder receives oily mixture, e.g. oil sludge or oil sands. The oily mixture
is frozen at 604. The
frozen oily mixture is broken at 606 into pieces. The pieces are moved into a
dehydrator at 608.
The pieces are heated and dehydrated with microwave at 610. In one embodiment,
at 610, the
pieces are heated such that both water and light-weight hydrocarbon in the
pieces can evaporate.
[0086] Water steam generated from the dehydration is extracted and
processed at
612. At 614, the dehydrated pieces are moved into a cracker. The dehydrated
pieces are heated at
616 with microwave for thermal cracking to generate cracked gas and sludge
residues. At 618, the
cracked gas is extracted and processed. The sludge residues are collected and
processed at 620.
[0087] It can be understood that in accordance with various
embodiments, the
process of thermal cracking oily mixture with microwave may be performed with
an order different
from the order shown in FIG. 6.
21
Date Recue/Date Received 2021-04-22
[0088] FIG. 7 is a flowchart of an exemplary process for extracting
and processing
steam generated from dehydration, according to an embodiment of the present
teaching. This may
be a detailed process for the step 612 shown in FIG. 6.
[0089] At 702, steam generated from dehydration is pumped out, e.g.
by a blower.
At 704, the pumped steam is divided into two pipes. The process may be then
divided into two
branches. Steam in one pipe is processed following steps 706 to 710; while
steam is the other pipe
is processed following steps 712 to 716.
[0090] At 706, the steam in one pipe is transported to a heat
exchanger. At the heat
exchanger, the steam is heated at 708 with cracked gas generated during
thermal cracking. At 710,
the heated steam is provided as a gas source of the air curtains that separate
the two chambers in the
thermal cracking furnace or separate the thermal cracking furnace from
outside.
[0091] At 712, the steam in the other pipe is transported to a
condenser. At 714, the
steam is cooled and condensed into water at the condenser. At 716, the water
is sprayed onto the
sludge residues for cooling the sludge residues generated during thermal
cracking.
[0092] It can be understood that in accordance with various
embodiments, the
process for extracting and processing steam generated from dehydration may be
performed with an
order different from the order shown in FIG 7.
[0093] FIG. 8 is a flowchart of an exemplary process for extracting
and processing
cracked gas generated from thermal cracking, according to an embodiment of the
present teaching.
This may be a detailed process for the step 618 shown in FIG. 6.
[0094] At 802, the cracked gas generated from thermal cracking is
pumped out. The
cracked gas may comprise light-weight oil components, some dust and some
water. At 804, dust in
the pumped cracked gas is filtered out. Pressure of the filtered cracked gas
is increased at 806. At
808, the cracked gas is then cooled at the heat exchanger with water steam
generated during
dehydration. The cracked gas is further cooled at 810 to generate a mixture of
gas and liquid.
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Date Recue/Date Received 2021-04-22
[0095] The gas liquid mixture may include gas, oil, and water. The
gas liquid
mixture may be conveyed at 812 into a three-phase separator that includes a
gas chamber, an oil
chamber, and a water chamber. Gas is separated at 814 from the mixture into
the gas chamber at
the three-phase separator for discharge. Oil is separated at 816 from the
mixture into the oil
chamber at the three-phase separator for discharge. Water is separated at 818
from the mixture into
the water chamber at the three-phase separator for discharge.
[0096] It can be understood that in accordance with various
embodiments, the
process for extracting and processing cracked gas generated from thermal
cracking may be
performed with an order different from the order shown in FIG. 8.
[0097] FIG. 10 shows an exemplary application environment for thermal
cracking
oily mixture with microwave, according to an embodiment of the present
teaching. As shown in
FIG. 10, oil sands collected at a mine 1000 may be a source of the oily
mixture. Oil sands are either
loose sands or partially consolidated sandstone containing a naturally
occurring sand, clay or other
minerals, water and bitumen. For example, at an oil sand mine 1000, the
thermal cracking process
100 described in the present teaching may be applied to process the oil sands
to generate steam,
cracked gas, and sludge residues, that can all be processed either for
resource reuse or for safe
disposal into the environment.
[0098] FIG. 11 shows another exemplary application environment for
thermal
cracking oily mixture with microwave, according to an embodiment of the
present teaching. As
shown in FIG. 11, oil sludge generated during oil exploitation 1100 may be a
source of the oily
mixture. Oil sludge may be a solid or gel in oil caused by the oil gelling or
solidifying. For
example, crude oil at an oil extraction plant 1100 may be performed with a
separation of oil, mud,
water, which can generate a large amount of oil sludge. The thermal cracking
process 100
described in the present teaching may be applied to process the oil sludge at
the oil extraction plant
to generate steam, cracked gas, and sludge residues, that can all be processed
either for resource
reuse or for safe disposal into the environment.
23
Date Recue/Date Received 2021-04-22
[0099] FIG. 12 shows yet another exemplary application environment
for thermal
cracking oily mixture with microwave, according to an embodiment of the
present teaching. As
shown in FIG. 12, oil sludge generated during oil refinery 1200 may be another
source of the oily
mixture. An oil refinery or petroleum refinery is an industrial process plant
where crude oil is
processed and refined into more useful products such as petroleum naphtha,
gasoline, diesel fuel,
liquefied petroleum gas, etc. Depending on the various types of refinery
processes, different types
of oil sludge may be generated. The thermal cracking process 100 described in
the present teaching
may be applied to process any type of the oil sludge generated during oil
refinery to generate steam,
cracked gas, and sludge residues, that can all be processed either for
resource reuse or for safe
disposal into the environment.
[00100] FIG. 13 shows still another exemplary application environment
for thermal
cracking oily mixture with microwave, according to an embodiment of the
present teaching. As
shown in FIG. 13, oil sludge generated during oil storage 1300 may be another
source of the oily
mixture. At the bottom of a storage tank, e.g. below the position of 2.5
meters, a large amount of
oil sludge can sediment every year. The thermal cracking process 100 described
in the present
teaching may be applied to process the oil sludge sediment in oil storage to
generate steam, cracked
gas, and sludge residues, that can all be processed either for resource reuse
or for safe disposal into
the environment.
[00101] While the foregoing has described what are considered to
constitute the
present teachings and/or other examples, it is understood that various
modifications may be made
thereto and that the subject matter disclosed herein may be implemented in
various forms and
examples, and that the teachings may be applied in numerous applications, only
some of which
have been described herein. It is intended by the following claims to claim
any and all applications,
modifications and variations that fall within the true scope of the present
teachings.
24
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