A pyrolysis oil and gas purification method and system for oil washing and water washing

Abstract

A dual-purpose oil-washing and water-washing pyrolysis oil and gas purification method and system, involving the field of waste plastic and oil sludge treatment, includes a primary spray tower, a pyrolysis oil circulation delivery pump, a sedimentation tank and a secondary spray condensation device; the bottom of the primary spray tower is connected to the pyrolysis oil circulation delivery pump through a primary output pipeline, and the circulation delivery pump is connected to an oil output pipeline for outputting oil liquid; a primary oil circulation main pipeline is connected between the bottom of the primary spray tower and the top of the primary spray tower; the bottom of the primary spray tower is connected to the sedimentation tank through a sedimentation pipeline, and a water circulation main pipeline is connected between the sedimentation tank and the top of the primary spray tower; the top of the primary spray tower is connected to the secondary spray condensation device through a connecting pipeline. The problem of pipeline and equipment blockage in the existing waste plastic and oil sludge high-temperature pyrolysis oil and gas condensation process is solved, and oil washing and water washing are mutually standby, oil and water are used for both purposes, blockage is prevented, and the conversion of waste plastic to pyrolysis oil and the recovery of petroleum hydrocarbons are realized.

Description

Technical Field

[0001] The present invention belongs to the field of waste plastic and oil sludge treatment, but is not limited to waste plastic and oil sludge treatment. It also includes raw materials such as tires and biomass, and specifically relates to a dual-purpose oil-washing and water-washing pyrolysis oil and gas purification method and system. Background Art

[0002] The resource utilization of waste plastics is a disruptive technology that determines the future development of the plastics industry. It involves multiple technical routes such as physical recycling and chemical recycling, spanning multiple disciplines such as material processing, chemical technology, and environmental science, and runs through the entire process of "double-chain integration" of the innovation chain and industrial chain, including core technology development, process environmental protection, policy and standard formulation. Among them, the chemical recycling of waste plastics is aimed at recycling waste plastics, and the pyrolysis of waste plastics is the first step to convert waste plastics into pyrolysis oil of waste plastics, providing raw materials for fine chemicals in the subsequent chemical cycle.

[0003] As a strategic resource, oil plays an irreplaceable role in the economic development of all countries. However, a large amount of hazardous waste, oily sludge (referred to as sludge), is often generated during oil exploration, mining, transportation, storage and refining. Recycling petroleum hydrocarbons from oily sludge can alleviate the shortage of fuel resources in the world.

[0004] Due to the diversity of waste plastic raw materials, the pyrolysis process is uncertain. The complexity of the distillation range of the pyrolysis oil condensed from the high-temperature pyrolysis oil gas leads to the problem of pipeline and equipment blockage during the condensation process. Similarly, the oil sludge contains a lot of sediment, resulting in a large amount of particles and dust in the pyrolysis oil, which will block the tower and pipeline during the deposition process.

[0005] To this end, in view of the pain points and difficulties faced in the high-temperature pyrolysis oil and gas condensation process, it is urgent to develop a green, efficient, economically and socially beneficial method and system for purifying waste plastics by high-temperature pyrolysis oil and gas. Summary of the invention

[0006] The technical problem solved by the present application is: to overcome the deficiencies of the prior art, to provide a dual-purpose oil-washing and water-washing pyrolysis oil and gas purification method and system, to solve the problem of pipeline and equipment blockage occurring during the existing waste plastic and oil sludge high-temperature pyrolysis oil and gas condensation process, and to realize a structure in which oil washing and water washing serve as backup for each other and oil and water are dual-purpose, to prevent system blockage, and to realize the conversion of waste plastic into pyrolysis oil and the recovery of petroleum hydrocarbons.

[0007] The technical solutions provided by this application are as follows:

[0008] An oil-washing and water-washing dual-purpose pyrolysis oil and gas purification system comprises a primary spray tower, a pyrolysis oil circulation delivery pump, a sedimentation tank and a secondary spray condensation device;

[0009] The bottom of the primary spray tower is connected to the pyrolysis oil circulation delivery pump through a primary output pipeline, and the pyrolysis oil circulation delivery pump delivers the pyrolysis oil through the oil circulation pipeline to circulate again into the bottom of the primary spray tower, and the circulation delivery pump is connected to an oil output pipeline for outputting the oil;

[0010] A primary oil circulation main pipeline is connected between the bottom of the primary spray tower and the top of the primary spray tower;

[0011] The bottom of the first-stage spray tower is connected to the sedimentation tank through a sedimentation pipeline, and a water circulation main pipeline is connected between the sedimentation tank and the top of the first-stage spray tower;

[0012] The top of the first-stage spray tower is connected to the second-stage spray condensation device through a connecting pipe;

[0013] The high-temperature pyrolysis gas enters the primary spray tower through the inlet pipe and is condensed to obtain pyrolysis oil.

[0014] The primary oil circulation main pipeline includes a first primary pipeline, a primary spray circulation pump, a second primary pipeline, a primary heat exchanger and a primary spray pipeline. The primary spray tower is connected to the primary spray circulation pump through the first primary pipeline; the primary spray circulation pump is connected to the primary heat exchanger through the second primary pipeline; and the primary heat exchanger is connected to the top of the primary spray tower through the primary spray pipeline.

[0015] The sedimentation tank comprises a tank body, a partition is arranged in the tank body, the height of the partition is lower than the height of the tank body, the partition divides the tank body into a sedimentation area and an overflow area, the condensed pyrolysis oil enters the sedimentation area, the impurities in the pyrolysis oil are precipitated to the bottom of the sedimentation area, and the oil of the pyrolysis oil overflows from the top of the partition into the overflow area; one end of the primary oil circulation main pipeline is connected to the sedimentation area.

[0016] The primary oil circulation main pipeline includes a water circulation pipeline and a water circulation spray pump. The sedimentation tank is connected to the water circulation spray pump through the water circulation pipeline. The water circulation spray pump is connected to the second primary pipeline, so that the water in the sedimentation tank passes through the water circulation spray pump and the second primary pipeline and enters the primary heat exchanger, and finally flows from the primary heat exchanger into the top of the primary spray tower.

[0017] The sedimentation tank is connected with a sedimentation tank pyrolysis oil output pipeline and a mud output pipeline. The sedimentation tank pyrolysis oil output pipeline is connected with the overflow area, and the mud output pipeline is connected with the bottom of the precipitation area.

[0018] The connecting pipe is an inclined pipe, and gradually inclines downward from the top of the first-stage spray tower.

[0019] The secondary spray condensation device comprises a secondary spray tower, wherein a first secondary pipeline, a second secondary pipeline, a secondary heat exchanger and a secondary spray pipeline are sequentially connected between the bottom and the top of the secondary spray tower, and the secondary spray tower is connected to a pyrolysis gas output pipeline.

[0020] The primary heat exchanger and the secondary heat exchanger are both provided with steam pipelines. When the pyrolysis oil condenses and blocks the pipelines, the cooling water of the primary heat exchanger and the secondary heat exchanger is cut off, and high-temperature steam is introduced into the steam pipelines to clear the blocked position where the pyrolysis oil is located through heat exchange.

[0021] A method for purifying high-temperature pyrolysis oil and gas by using an oil-washing and water-washing dual-purpose pyrolysis oil and gas purification system as described above, comprising:

[0022] Oil washing is performed first. If the outlet temperature of the first-stage spray tower rises above the set threshold or the circulation flow of the oil through the first-stage circulation pipeline decreases, it is switched to water washing, otherwise oil washing continues.

[0023] The oil washing includes: closing the settling pipeline to cut off the bottom of the first-stage spray tower from the settling tank; the high-temperature pyrolysis oil and gas enter the first-stage spray tower through the inlet pipeline, the pyrolysis oil in the first-stage spray tower enters the first-stage spray tower through the first-stage oil circulation main pipeline to condense the incoming high-temperature pyrolysis oil and gas, and the uncondensed high-temperature pyrolysis oil and gas enter the second-stage spray condensation device through the connecting pipeline to condense, completing the cycle, and sending the condensed pyrolysis oil out through the circulation delivery pump;

[0024] The water washing includes: closing the primary oil circulation main pipeline, opening the sedimentation pipeline to connect the bottom of the primary spray tower with the sedimentation tank; the high-temperature pyrolysis oil and gas enter the primary spray tower, and the circulating water and pyrolysis oil in the primary spray tower all enter the sedimentation tank, where the oil, water and dust are precipitated and separated, the upper layer of pyrolysis oil will overflow and be sent out, and the dust will settle to the bottom of the sedimentation tank, and the middle layer of water enters the top of the primary spray tower through the water circulation main pipeline; at the same time, the uncondensed high-temperature pyrolysis oil and gas enter the secondary spray condensation device from the top of the primary spray tower for condensation.

[0025] The remarkable effects of the present invention mainly include the following points:

[0026] (1) Oil-washing and water-washing dual-purpose structure. The overall raw material applicability of the device is wide, so the subsequent process equipment needs to have a wide range of applicability. Oil washing and water washing each have their own characteristics, with oil washing being the first choice. When raw materials that are not suitable for the oil washing cycle appear, such as when the dust content in the pyrolysis oil is high, more and more sludge accumulates in the tower kettle, affecting the spray cycle, it is necessary to switch to water washing.

[0027] (2) Anti-blocking structure for the circulating oil washing of the tower bottom. The dust content is the highest at the bottom of the first-stage spray tower. Therefore, a circulating pipeline is set behind the pyrolysis oil circulating delivery pump to keep the pyrolysis oil in the tower bottom flowing so that there is no static dead corner in the pipeline to prevent the tower bottom from being blocked.

[0028] (3) Anti-blocking structure of system pipelines. The inlet pipeline and connecting pipeline are inclined pipelines to prevent high-temperature pyrolysis gas (pyrolysis gas) from condensing in the pipeline and clogging the pipeline in the straight pipe. In the entire circulation pipeline, the properties of the pyrolysis oil in the first-stage spray circulation process are the worst (containing more heavy oil), but the condensation of pyrolysis oil may occur at the low point of local temperature, causing blockage of equipment and pipelines. The most likely place in the entire circulation is inside the heat exchanger. Therefore, high-temperature steam is added to the cooling medium side of the heat exchanger. Once a blockage problem occurs, stop the heat exchange and purge the heat exchanger until the pyrolysis oil regains fluidity. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a structural schematic diagram of a dual-purpose oil-washing and water-washing pyrolysis oil and gas purification method and system described in the present invention.

[0030] Explanation of the accompanying figures: 1. Primary spray tower; 2. Pyrolysis oil circulation delivery pump; 3. Primary spray circulation pump; 4. Primary heat exchanger; 5. Sedimentation tank; 6. Secondary spray tower; 7. Secondary spray circulation pump; 8. Secondary heat exchanger; 9. Water circulation spray pump.

[0031] 1-1, inlet pipeline; 1-2, connecting pipeline; 1-3, pyrolysis gas output pipeline; 1-4, secondary spray tower water output pipeline; 1-5, oil circulation pipeline; 1-6, primary output pipeline; 1-7, sedimentation pipeline; 1-8, oil output pipeline; 1-9, water circulation pipeline; 1-10, mud (water-dust mixture) output pipeline; 1-11, sedimentation tank pyrolysis oil output pipeline; 1-12, first primary pipeline; 1-13, second primary pipeline; 1-14, primary spray pipeline; 1-15, first secondary pipeline; 1-16, second secondary pipeline; 1-17, secondary spray pipeline. DETAILED DESCRIPTION

[0032] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments disclosed in the present invention will be further described in detail below with reference to the accompanying drawings.

[0033] The embodiment of the present application discloses a purification system for generating pyrolysis oil from high-temperature pyrolysis oil and gas for both oil washing and water washing. The system relies on the chemical cycle of waste plastics and resource recovery, aims at pyrolysis plastic oil and sludge oil products, solves the problem of equipment and system blockage in the condensation process of high-temperature pyrolysis oil and gas, and realizes water washing and oil washing as backup for each other, and is suitable for various forms of raw materials.

[0034] like Figure 1As shown, the overall process system includes: a primary spray tower 1, a pyrolysis oil circulation delivery pump 2, a primary spray circulation pump 3, a primary heat exchanger 4, a settling tank 5, a secondary spray tower 6, a secondary spray circulation pump 7, a secondary heat exchanger 8, and a water circulation spray pump 9. Among them, the high-temperature pyrolysis gas enters the primary spray tower 1 through the inlet pipe 1-1; the bottom of the primary spray tower 1 is connected to the settling tank 5 through the settling pipeline 1-7; the bottom of the primary spray tower 1 is connected to the pyrolysis oil circulation delivery pump 2 through the primary output pipeline 1-6, and the pyrolysis oil circulation delivery pump 2 delivers the pyrolysis oil to the bottom of the primary spray tower 1 again through the oil circulation pipeline 1-5, and the circulation delivery pump 2 sends it out through the oil output pipeline 1-8; the primary spray tower 1 is connected to the primary spray circulation pump 3 through the first primary pipeline 1-12; the primary spray circulation pump 3 is connected to the primary heat exchanger 4 through the second primary pipeline 1-13; the primary heat exchanger 4 is connected to the primary spray tower 1 through the primary spray pipeline 1-14 The first-stage spray tower 1 is connected to the second-stage spray tower 6 through the connecting pipe 1-2; the second-stage spray tower 6 is connected to the second-stage spray circulation pump 7 through the first second-stage pipeline 1-15; the second-stage spray circulation pump 7 is connected to the second-stage heat exchanger 8 through the second second-stage pipeline 1-16; the second-stage heat exchanger 8 is connected to the second-stage spray tower 6 through the second-stage spray pipeline 1-17; the liquid in the second-stage spray tower 6 is sent out through the second-stage spray tower water output pipeline 1-4. The second-stage spray tower 6 is connected to the pyrolysis gas output pipeline 1-3, and the high-temperature pyrolysis oil and gas that is not completely condensed in the second-stage spray tower 6 is discharged through the pyrolysis gas output pipeline 1-3 or sent to the next-stage spray tower.

[0035] In order to achieve the purpose of the present invention, the present invention proposes a dual-purpose oil-washing and water-washing pyrolysis oil and gas purification method and system, comprising the following steps:

[0036] Oil washing process:

[0037] The high-temperature pyrolysis oil and gas enter the first-level spray tower 1 through the inlet pipe 1-1. The inlet pipe 1-1 is an inclined pipe to prevent the high-temperature pyrolysis gas from condensing in the pipe and clogging the pipe in the straight pipe. The pyrolysis oil in the tower body (which can be replaced by other media initially) is sent to the first-level heat exchanger 4 through the first-level spray circulation pump 3 to cool the high-temperature pyrolysis oil through heat exchange, and then enter the first-level spray tower 1 to condense the incoming high-temperature pyrolysis oil and gas to complete the cycle, while the uncondensed high-temperature pyrolysis oil and gas enter the second-level spray tower 6 through the pipeline 1-2 for condensation. At the same time, the pyrolysis oil in the kettle of the first-level spray tower 1 is sent out through the pyrolysis oil circulation delivery pump 2. At the same time, a stream of pyrolysis oil enters the kettle of the first-level spray tower 1 through the circulation pipe to keep the kettle liquid level stable while the pyrolysis oil is always flowing to prevent clogging the bottom of the kettle and the pipeline.

[0038] Washing process:

[0039] Stop the primary spray circulation pump 3 and the pyrolysis oil circulation delivery pump 2, open the valve between the primary spray tower 1 and the sedimentation tank 5, and open the valve behind the water circulation spray pump 9; close the valve between the primary spray tower 1 and the pyrolysis oil circulation delivery pump 2, close the valve behind the primary spray circulation pump 3, and switch the oil washing system to the water washing system.

[0040] The high-temperature pyrolysis oil and gas enter the primary spray tower 1. The circulating water in the tower body is initially added with production water for spray condensation. The condensed pyrolysis oil and circulating water all enter the sedimentation tank 5. In the sedimentation tank, the oil, water and dust phases will be separated by sedimentation. The pyrolysis oil in the upper layer will overflow and be collected and finally sent out of the equipment. The dust will settle to the bottom of the sedimentation tank 5 and can be discharged at a fixed time. The water in the middle layer enters the primary spray tower 1 through the water circulation spray pump 9 and the primary heat exchanger 4 for heat exchange, and the cycle repeats.

[0041] The high-temperature pyrolysis oil and gas enter the top of the secondary spray tower 6 from the top of the primary spray tower 1. At this time, the connecting pipe 1-2 is an inclined pipe, which also prevents the pyrolysis gas from condensing in the pipe and clogging the pipe in the straight pipe. The secondary spray tower 6 will send industrial water into the tower kettle in advance, and circulate heat exchange spray through the secondary spray circulation pump 7 and the secondary heat exchanger 8 to achieve cyclic condensation. In the implementation process, the secondary spray can be changed to a second to fourth spray (increasing the spray cycle) according to the properties and distillation range distribution of the high-temperature pyrolysis oil and gas, and the cooling medium of the heat exchanger can be adjusted according to requirements, such as industrial water, chilled water, etc.

[0042] At the same time, in order to prevent the pyrolysis oil from being blocked due to sudden temperature changes, a steam pipeline is added to the cold logistics inlet of the heat exchanger. When the pyrolysis oil condenses and blocks the pipeline, the cooling water will be cut off and high-temperature steam will be introduced to clear the blocked position where the pyrolysis oil is located through heat exchange.

[0043] The following is combined with Figure 1 The present invention is further explained and illustrated.

[0044] like Figure 1 As shown:

[0045] High-temperature pyrolysis oil and gas ~450℃ enter the first-level spray tower 1 through the inlet pipe 1-1. The inlet pipe 1-1 is an inclined pipe to prevent the high-temperature pyrolysis gas (pyrolysis gas) from condensing in the pipe and clogging the pipe easily. After entering the first-level spray tower 1, it performs countercurrent heat exchange with the pyrolysis oil ~65℃ after passing through the first-level heat exchanger 4, and keeps the temperature of the first-level spray tower 1 at about 105℃. According to the properties of the waste plastic pyrolysis oil, the pyrolysis oil at this temperature has good fluidity. In order to maintain the fluidity of the equipment and pipelines and prevent clogging, the temperature of the pyrolysis oil after heat exchange is maintained at about 65℃, so the cooling medium of the first-level heat exchanger 4 is hot water with an inlet of 40℃ and an outlet of 55℃. At the same time, the pyrolysis oil at the bottom of the first-level spray tower 1 is transported outward by the pyrolysis oil circulation pump 2, and a small amount of pyrolysis oil is circulated back to the first-level spray tower 1 kettle, so that the first-level spray tower 1 kettle and pipeline are always fluid, without dead zones, and the first-level spray tower 1 kettle is prevented from being slabbed and blocked. Similarly, in order to prevent the local temperature from being too low and causing the pipeline to be blocked, high-temperature steam is also added to the cooling medium side of the first-stage heat exchanger 4. Once a blockage problem occurs, the heat exchange is stopped and the heat exchanger is purged until the pyrolysis oil regains fluidity. When the dust content of the high-temperature pyrolysis oil gas is large, affecting the first-stage oil washing spray cycle, it is necessary to switch the oil washing to water washing.

[0046] Stop the primary spray circulation pump 3 and the pyrolysis oil circulation delivery pump 2, open the valve between the primary spray tower 1 and the sedimentation tank 5, and open the valve behind the water circulation spray pump 9; close the valve between the primary spray tower 1 and the pyrolysis oil circulation delivery pump 2, close the valve behind the primary spray circulation pump 3, and switch the oil washing system to the water washing system. At this time, a large amount of water and a small amount of condensed pyrolysis oil enter the sedimentation tank 5 for sedimentation. Due to the density difference, oil, water, and dust will be stratified. There is a partition in the sedimentation tank 5. The accumulated pyrolysis oil overflows into the partition and then is sent out intermittently. The mud, dust and water mixture settled at the bottom of the sedimentation tank 5 is also sent out intermittently at regular intervals. The water phase in the middle layer will enter the primary heat exchanger 4 through the water circulation spray pump 9 for heat exchange cooling or heating, and then enter the primary spray tower 1 for direct contact condensation with the high-temperature pyrolysis oil and gas, completing a cycle, and repeating over and over again.

[0047] After the high-temperature pyrolysis oil and gas are condensed once, the pyrolysis gas enters the secondary spray tower 6 through the connecting pipe 1-2. The connecting pipe 1-2 is an inclined pipe to prevent the high-temperature pyrolysis gas (pyrolysis gas) from condensing in the pipe and clogging the pipe in the straight pipe. The interior of the tower kettle of the secondary spray tower 6 is a water phase. Since most of the heavy oil has been collected by the primary spray tower 1 after the pyrolysis gas has been condensed at the primary level, the target at this time is the pyrolysis oil of small molecules. The pyrolysis gas at ~105°C enters the secondary spray tower 6 and exchanges heat with the spray water at ~55°C for condensation. At this time, the temperature of the cooling medium of the secondary heat exchanger 8 is: 32°C for inlet water and 40°C for outlet water. Similarly, in order to prevent the local temperature from being too low and causing the pipeline to be blocked, high-temperature steam is also added to the cooling medium side of the secondary heat exchanger 8. Once a blockage problem occurs, the heat exchange is stopped and the heat exchanger is purged until the pyrolysis oil regains fluidity. The tower kettle of the secondary spray tower 6 is provided with an outward delivery pipeline to maintain the liquid level balance inside the tower kettle.

[0048] If the molecular composition of high-temperature pyrolysis gas is complex and the condensed pyrolysis oil has a long distillation range, the number of condensation stages can be increased. For example, the pyrolysis gas after secondary condensation still contains a small amount of pyrolysis oil. When considering low temperature, it is necessary to consider the problem of pipeline blockage caused by the precipitation of pyrolysis oil and the precipitation of water molecules in the air at low temperature. Therefore, the pyrolysis gas is condensed twice and then goes to the subsequent spray tower. The 65°C pyrolysis gas is heat exchanged with 15°C chilled water to deep cool the pyrolysis gas to 20°C and keep it cold. Similarly, the pyrolysis oil cooled down from the spray tower kettle and the heated water are sent to the heat exchanger through a circulating pump for heat exchange. The temperature of the cooling medium of the heat exchanger is: 7°C for inlet water and 12°C for outlet water. Similarly, high-temperature steam is added to one side of the cooling medium of the heat exchanger. Once a blockage problem occurs, the heat exchange is stopped and the heat exchanger is purged until the pyrolysis oil resumes fluidity again. The spray tower kettle is equipped with an outward delivery pipeline to maintain the liquid level balance inside the tower kettle.

[0049] The contents not described in detail in this application specification belong to the common knowledge of those skilled in the art.

[0050] The present application is described in detail above in conjunction with specific implementation methods and exemplary examples, but these descriptions cannot be understood as limiting the present application. Those skilled in the art understand that, without departing from the spirit and scope of the present application, a variety of equivalent replacements, modifications or improvements can be made to the technical solution of the present application and its implementation methods, all of which fall within the scope of the present application. The scope of protection of the present application shall be subject to the attached claims.

Claims

1. A dual-purpose oil-washing and water-washing pyrolysis oil and gas purification system, characterized in that: It comprises a primary spray tower (1), a pyrolysis oil circulation delivery pump (2), a sedimentation tank (5) and a secondary spray condensation device; The bottom of the first-stage spray tower (1) is connected to the pyrolysis oil circulation delivery pump (2) via a first-stage output pipeline (1-6), and the pyrolysis oil circulation delivery pump (2) delivers the pyrolysis oil through the oil circulation pipeline (1-5) to circulate again into the bottom of the first-stage spray tower (1), and the circulation delivery pump (2) is connected to an oil output pipeline (1-8) for outputting the oil; A primary oil circulation main pipeline is connected between the bottom of the primary spray tower (1) and the top of the primary spray tower (1); The bottom of the first-stage spray tower (1) is connected to the sedimentation tank (5) through a sedimentation pipeline (1-7), and a water circulation main pipeline is connected between the sedimentation tank (5) and the top of the first-stage spray tower (1); The top of the first-stage spray tower (1) is connected to the second-stage spray condensation device via a connecting pipe (1-2); The high-temperature pyrolysis gas enters the primary spray tower (1) through the inlet pipe (1-1) and is condensed to obtain pyrolysis oil.

2. The oil-washing and water-washing dual-purpose pyrolysis oil and gas purification system according to claim 1 is characterized in that: The primary oil circulation main pipeline comprises a first primary pipeline (1-12), a primary spray circulation pump (3), a second primary pipeline (1-13), a primary heat exchanger (4) and a primary spray pipeline (1-14); the primary spray tower (1) is connected to the primary spray circulation pump (3) via the first primary pipeline (1-12); the primary spray circulation pump (3) is connected to the primary heat exchanger (4) via the second primary pipeline (1-13); and the primary heat exchanger (4) is connected to the top of the primary spray tower (1) via the primary spray pipeline (1-14).

3. The oil-washing and water-washing dual-purpose pyrolysis oil and gas purification system according to claim 1 or 2, characterized in that: The sedimentation tank (5) comprises a tank body, a partition is arranged in the tank body, the height of the partition is lower than the height of the tank body, the partition divides the tank body into a sedimentation area and an overflow area, the condensed pyrolysis oil enters the sedimentation area, the impurities in the pyrolysis oil are precipitated to the bottom of the sedimentation area, and the oil of the pyrolysis oil overflows from the top of the partition into the overflow area; one end of the primary oil circulation main pipeline is connected to the sedimentation area.

4. The oil-washing and water-washing dual-purpose pyrolysis oil and gas purification system according to claim 3 is characterized by: The primary oil circulation main pipeline comprises a water circulation pipeline (1-9) and a water circulation spray pump (9); the sedimentation tank (5) is connected to the water circulation spray pump (9) through the water circulation pipeline (1-9); the water circulation spray pump (9) is connected to the second primary pipeline (1-13), so that the water in the sedimentation tank (5) passes through the water circulation spray pump (9) and the second primary pipeline (1-13) and enters the primary heat exchanger (4), and finally flows from the primary heat exchanger (4) into the top of the primary spray tower (1).

5. The oil-washing and water-washing dual-purpose pyrolysis oil and gas purification system according to claim 3 is characterized by: The sedimentation tank (5) is connected to a sedimentation tank pyrolysis oil output pipeline (1-11) and a mud output pipeline (1-10), the sedimentation tank pyrolysis oil output pipeline (1-11) is connected to the overflow area, and the mud output pipeline (1-10) is connected to the bottom of the precipitation area.

6. The oil-washing and water-washing dual-purpose pyrolysis oil and gas purification system according to claim 1 is characterized in that: The connecting pipe (1-2) is an inclined pipe, and gradually inclines downward from the top of the first-stage spray tower (1).

7. The oil-washing and water-washing dual-purpose pyrolysis oil and gas purification system according to claim 1 or 2, characterized in that: The secondary spray condensation device comprises a secondary spray tower (6), wherein a first secondary pipeline (1-15), a second secondary pipeline (1-16), a secondary heat exchanger (8) and a secondary spray pipeline (1-17) which are connected in sequence are arranged between the bottom and the top of the secondary spray tower (6), and the secondary spray tower (6) is connected to a pyrolysis gas output pipeline (1-3).

8. The oil-washing and water-washing dual-purpose pyrolysis oil and gas purification system according to claim 7 is characterized in that: The first-stage heat exchanger (4) and the second-stage heat exchanger (8) are both provided with steam pipelines. When the pyrolysis oil condenses and blocks the pipelines, the cooling water of the first-stage heat exchanger (4) and the second-stage heat exchanger (8) is cut off, and high-temperature steam is introduced into the steam pipelines to clear the blocked position where the pyrolysis oil is located through heat exchange.

9. A dual-purpose oil-washing and water-washing pyrolysis oil and gas purification method, characterized in that: The high-temperature pyrolysis oil and gas is purified using an oil-washing and water-washing dual-purpose pyrolysis oil and gas purification system as described in any one of claims 1 to 8, comprising: Oil washing is performed first. If the outlet temperature of the first-stage spray tower (1) rises above a set threshold or the circulating flow rate of the oil liquid passing through the first-stage circulation pipeline decreases, water washing is switched, otherwise oil washing is continued.

10. The oil-washing and water-washing dual-purpose pyrolysis oil and gas purification method according to claim 9, characterized in that: The oil washing comprises: closing the settling pipeline (1-7) to cut off the bottom of the first spray tower (1) from the settling tank (5); the high-temperature pyrolysis oil and gas enter the first spray tower (1) through the inlet pipeline (1-1); the pyrolysis oil in the first spray tower (1) enters the first spray tower (1) through the first oil circulation main pipeline to condense the incoming high-temperature pyrolysis oil and gas; at the same time, the uncondensed high-temperature pyrolysis oil and gas enter the second spray condensation device through the connecting pipeline (1-2) to be condensed, completing the cycle, and sending the condensed pyrolysis oil out through the circulation delivery pump (2); The water washing comprises: closing the primary oil circulation main pipeline, opening the sedimentation pipeline (1-7) so that the bottom of the primary spray tower (1) is connected to the sedimentation tank (5); the high-temperature pyrolysis oil gas enters the primary spray tower (1), and the circulating water and pyrolysis oil in the primary spray tower (1) all enter the sedimentation tank (5), and the oil, water and dust are precipitated and separated in the sedimentation tank, the pyrolysis oil in the upper layer will overflow and be sent out, the dust will settle to the bottom of the sedimentation tank (5), and the water in the middle layer will enter the top of the primary spray tower (1) through the water circulation main pipeline; at the same time, the high-temperature pyrolysis oil gas that has not been condensed enters the secondary spray condensation device from the top of the primary spray tower (1) to be condensed.

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