CA3008527C

CA3008527C - Method and system for processing oily mixture

Info

Publication number: CA3008527C
Application number: CA3008527A
Authority: CA
Inventors: Yan Zhang; Yingfei HOU
Original assignee: Cyc Machinery Inc
Current assignee: Cyc Machinery Inc
Priority date: 2015-12-25
Filing date: 2015-12-25
Publication date: 2021-06-15
Anticipated expiration: 2035-12-25
Also published as: CN117566996A; CA3191635A1; CN109153918A; CA3008527A1; CA3116018A1; WO2017107157A1; CA3116018C

Abstract

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.

Description

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,

7 PCT/CN2015/098810 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.

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.

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;

[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.

[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, uniform 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 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 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 burn 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 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.

[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 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 50% 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 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 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

57 PCT/CN2015/098810 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 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.

[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.

[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 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 thermal 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.

[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 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 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.

[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.

[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.

[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.

Claims

WE CLAIM

1. A method for processing an oily mixture, the method comprising:
receiving the oily mixture;
freezing the oily mixture to generate a frozen oily mixture;
breaking the frozen oily mixture into pieces;
dehydrating the pieces in a first heating process to generate dehydrated pieces, wherein the first heating process applies a first temperature; and cracking the dehydrated pieces in a second heating process, wherein the second heating process applies a second temperature different from the first temperature.

2. The method of claim 1, wherein microwave heating is utilized during the first heating process, the second heating process, or the first heating process and the second heating processes.

3. The method of claim 1, wherein the oily mixture comprises a liquid component and a solid component.

4. The method of claim 1, wherein the oily mixture comprises at least one of oil sludge, oil sand, or oily wastewater.

5. The method of claim 1, further comprising:
extracting hydrocarbon from the dehydrated pieces during the first heating process, the second heating process, or both the first heating process and the second heating process.

6. The method of claim 1, wherein each of the pieces is smaller than 40 cm along any direction.

7. The method of claim 1, wherein temperatures of the pieces are below 205 degrees Celsius during the first heating process.
Date Recue/Date Received 2020-09-23

8. The method of claim 1, wherein temperatures of the dehydrated pieces are above 400 degree Celsius during the second heating process.

9. The method of claim 1, wherein an anaerobic environment is used to perform the first heating process, the second heating process, or the first heating process and the second heating process.

10. A system for processing an oily mixture, the system comprising:
a material feeder configured for:
receiving the oily mixture, 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, wherein the first heating process applies a first temperature; and an oily mixture cracker configured for cracking the dehydrated pieces in a second heating process, wherein the second heating process applies a second temperature different from the first temperature.

11. The system of claim 10, further comprising:
a residue processor configured for processing gas and residue generated during the first heating process and the second heating process.

Date Recue/Date Received 2020-09-23