System and method for recycling light components

Abstract

The invention relates to a system and a method for recycling light components, a settling separator of the system adopts a self-balance line with fire retardance, so as to realize feeding and discharging of materials, and gas in equipment can be freely balanced, so that oil gas emission and inert gas supplementation are reduced, and flame propagation is prevented at the same time; gas in a self-balance line is sent to a washing tower through a liquid seal washer; gas in the washing tower is conveyed to a heating furnace through a Roots blower to be burnt together with fuel gas, so that light components are recycled; meanwhile, each settling separator and each liquid seal washer are provided with a nitrogen supplementing pipeline and an emergency cut-off isolation facility, and in an emergency, the emergency cut-off isolation facility can quickly close and block a material flow and supplement inert gas to dilute combustible gas, so that the system pressure balance and the system cut-off are realized through self pressure balance. The problems of environmental pollution, light component gas flash explosion risk, resource waste and the like caused by volatilization of solvent storage light components can be effectively solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil refining and coal chemical industry, in particular to a system and method for recovering and processing light components. BACKGROUND

[0002] The asphaltene content in coal direct liquefaction pitch is 40-50%, and it is extremely necessary to actively explore the way to realize efficient utilization of coal direct liquefaction residue, effectively recycle and utilize coal direct liquefaction by-products, produce coal-based pitch products of different grades, and build a complete industry chain of coal-to-oil.

[0003] Specifically, taking the coal direct liquefaction pitch purification process as an example, the coal direct liquefaction pitch is subjected to a series of process procedures such as solvent dissolution, separation, sedimentation, flashing, pitch forming, and drying, to realize solid-liquid separation of the solid-containing material and recovery of the solvent, so as to obtain the target product and the by-product coal liquefaction solid fuel. In actual operation, the extraction solvent is mixed with the coal liquefaction pitch, and after extraction and separation, the separated clear liquid is subjected to high-temperature low-pressure flashing to extract the solvent, and the separated solid phase is subjected to high-temperature instantaneous reduced-pressure flashing to recover the solvent, so as to realize the cyclic utilization of the solvent, and the target product is obtained after separation. However, the solvent is operated at a temperature higher than its flash point for a long time, and during the high-temperature operation of the heating furnace, part of the solvent will undergo cracking reaction to produce light component substances, and the light components and harmful substances in the solvent itself will also be released. In order to ensure safe operation, all equipment is sealed with nitrogen. The light component gas of the solvent, the harmful substances (such as benzopyrene) contained in the solvent itself, and the supplemented inert nitrogen need to be discharged in large quantities. There are many problems in the discharge process, such as equipment overpressure, safety hazards, environmental impact, and resource waste. In order to eliminate hidden dangers, optimize the environment, and improve resource utilization, the recovery and treatment of light components after solvent storage and high-temperature volatilization also become a big problem.

[0004] Therefore, it is urgent to develop a recovery and treatment system and method to solve the above problems. SUMMARY

[0005] The purpose of the present application is to provide a system and method for recovering and processing light components, which can effectively solve the problems of environmental pollution, safety hazards, and resource waste caused by solvent storage and light component volatilization.

[0006] In order to achieve the above-mentioned purpose, the present application provides a system for recovering and processing light components, which comprises a centrifuge, an induced draft fan, a first sedimentation separator, a second sedimentation separator, an emergency cut-off isolation facility, a liquid seal scrubber, a liquid seal scrubber circulating pump, a scrubbing tower, a scrubbing tower circulating wash oil cooler, a scrubbing tower circulating pump, a Roots blower, a heating furnace, and a flare tank. The casing exhaust port of the centrifuge is communicated with the feed port of the suction fan; the discharge port of the suction fan is communicated with the first feed port of the liquid seal scrubber; the liquid phase discharge port of the liquid seal scrubber is communicated with the feed port of the liquid seal scrubber circulating pump; one part of the discharge port of the liquid seal scrubber liquid phase circulating pump is communicated with the second feed port of the liquid seal scrubber, and the other part is sent back to the recovery; The gas phase discharge port of the first settling separator is respectively connected with a self-balanced line with a flame arrestor; the self-balanced line with the flame arrestor is provided with the emergency cut-off isolation facility; the gas phase discharge port is communicated with the feed port of the emergency cut-off isolation facility; the discharge port of the emergency cut-off isolation facility is communicated with the discharge port of the second settling separator in one way; and the other way is communicated with the third feed port of the liquid seal scrubber; The gas phase discharge port of the liquid seal scrubber is communicated with the first feed port of the scrubbing tower; one part of the gas phase discharge port of the scrubbing tower is communicated with the feed port of the Roots blower, and the other part is returned to the scrubbing tower; the discharge port of the Roots blower is respectively communicated with the feed ports of the heating furnace and the flare tank; The liquid phase discharge port of the scrubbing tower is communicated with the feed port of the scrubbing tower circulating wash oil cooler.

[0007] Optionally, the first settling separator and the second settling separator are respectively provided with a top liquid discharge pipeline, an intermediate liquid discharge pipeline and a bottom intermediate liquid discharge pipeline; the top liquid discharge pipeline is provided with a top liquid discharge valve; the intermediate liquid discharge pipeline is provided with an intermediate liquid discharge valve; and the bottom intermediate liquid discharge pipeline is provided with a bottom intermediate liquid discharge valve.

[0008] Optionally, the first settling separator and the second settling separator are respectively provided with a feed pipeline, and the feed pipeline is provided with a feed valve.

[0009] Optionally, a balance valve is arranged on the pipeline between the first settling separator and the second settling separator.

[0010] Optionally, the first settling separator and the second settling separator are respectively provided with a first nitrogen supplement pipeline, and the first nitrogen supplement pipeline is provided with a first nitrogen supplement valve.

[0011] Optionally, the liquid seal scrubber is provided with a second nitrogen supplement pipeline, and the second nitrogen supplement pipeline is provided with a second nitrogen supplement valve.

[0012] Optionally, a pressure control valve is arranged on the pipeline between the gas phase discharge port of the scrubbing tower and the first feed port of the scrubbing tower.

[0013] Optionally, a scrubbing tower backflow control valve is arranged on the pipeline between the liquid phase discharge port of the scrubbing tower and the feed port of the scrubbing tower circulating wash oil cooler.

[0014] Optionally, a part of the outlet of the circulating scrubbing tower oil cooler is communicated with the inlet of the circulating pump, and another part is sent back to the recovery system; the outlet of the circulating pump is communicated with the second inlet of the scrubbing tower; a scrubbing tower circulating oil sending valve is arranged on the outlet pipeline of the circulating scrubbing tower oil cooler.

[0015] Optionally, the outlet of the Roots blower is communicated with the fuel gas or combustion air inlet of the heating furnace.

[0016] Optionally, a flare cut-off valve is arranged on the pipeline between the outlet of the Roots blower and the flare tank inlet, and a gas sending valve is arranged on the pipeline between the outlet of the Roots blower and the fuel gas or combustion air inlet.

[0017] Another aspect of the present application provides a method for light component recovery treatment, which adopts the system provided in the above-mentioned aspect of the present application, and the method comprises the following steps: The induced draft fan induces the first light component from the centrifuge cover shell exhaust port, and the first light component is pressurized and sent to the liquid seal scrubber for first washing; The second light component is sent to the first settling separator for separation, and the separated gas phase is sent to the liquid seal scrubber through the self-balancing line of the band-pass fire for second washing; The gas phase after the first washing and the second washing of the liquid seal scrubber is sent to the scrubbing tower for further washing, and the washed gas phase is sent to the heating furnace or the flare tank through the Roots blower, and is burned with the fuel gas, combustion air or flare tank of the heating furnace.

[0018] Optionally, the first light component is pressurized to 5-20 KPa.

[0019] Optionally, the settling speed of the first settling separator is about 0.23-0.3 m / h, and the separation time is 24-72 h.

[0020] Optionally, the liquid seal pressure of the liquid seal scrubber is 1-3 KPa.

[0021] Optionally, the tower pressure of the scrubbing tower is 0.2-2 Mpa.

[0022] By the technical scheme, the self-balanced line with the flame barrier is adopted in the settling separator to realize the material in and out, so that the gas in the equipment can be freely balanced, thereby reducing the oil gas emission and inert gas supplement, and preventing the flame propagation; the excess gas in the self-balanced line is sent to the washing tower through the liquid seal scrubber; the excess gas in the washing tower is sent to the heating furnace or the flare tank for burning, so as to realize the recycling treatment of the light components; meanwhile, the nitrogen supplement pipeline and the emergency cut-off isolation facility are arranged in each settling separator and liquid seal scrubber, in the emergency, the emergency cut-off isolation facility can quickly close and block the material flow, the supplemental inert gas can dilute the combustible gas, and the system pressure balance and cut-off can be realized through the self-pressure balance. The present application can effectively solve the problems of environmental pollution, light component gas flash explosion risk and resource waste caused by solvent storage light component volatilization.

[0023] Other features and advantages of the present application will be described in detail in the following specific embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0024] The accompanying drawings are included to provide a further understanding of the present application, and constitute a part of the specification, and together with the specific embodiments below, serve to explain the present application, but do not constitute a limitation on the present application. In the drawings: Figure 1 is a system schematic diagram of the light component recycling treatment of the present application.

[0025] Explanation of reference signs 1-first settling separator; 2-emergency cut-off isolation facility; 3-balancing valve; 4-first nitrogen supplement valve; 5-top liquid discharge valve; 6-intermediate liquid discharge valve; 7-bottom liquid discharge valve; 8-feeding valve; 9-second nitrogen supplement valve; 10-liquid seal scrubber; 11-washing circulating pump; 12-pressure control valve; 13-washing tower; 14-washing tower reflux control valve; 15-washing tower circulating washing oil cooler; 16-washing tower circulating washing oil discharge valve; 17-washing tower circulating pump; 18-roots blower; 19-gas discharge valve; 20-flare cut-off valve; 21-second settling separator; 22-centrifuge; 23-extraction fan. DETAILED DESCRIPTION

[0026] The specific embodiments of the present application will be described in detail below in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present application, and are not used to limit the present application.

[0027] In one aspect, the present application provides a light component recycling treatment system, as shown in Figure 1The system comprises a centrifuge 22, a suction fan 23, a first settling separator 1, a second settling separator 21, an emergency cut-off isolation device 2, a liquid seal scrubber 10, a liquid seal scrubber circulating pump 11, a scrubbing tower 13, a scrubbing tower circulating wash oil cooler 15, a scrubbing tower circulating pump 17, a Roots blower 18, a heating furnace and a flare tank; The casing exhaust port of the centrifuge 22 is communicated with the feed port of the suction fan 23; the discharge port of the suction fan 23 is communicated with the first feed port of the liquid seal scrubber 10; the liquid phase discharge port of the liquid seal scrubber 10 is communicated with the feed port of the liquid seal scrubber circulating pump 11; one part of the discharge port of the liquid seal scrubber liquid phase circulating pump 11 is communicated with the second feed port of the liquid seal scrubber 10, and the other part is sent back to recovery; so as to realize solvent recovery and recycling; The gas phase discharge port of the first settling separator 1 is respectively connected with a self-balancing line with a flame barrier; the emergency cut-off isolation device 2 is arranged on the self-balancing line with a flame barrier; the gas phase discharge port is communicated with the feed port of the emergency cut-off isolation device 2; the discharge port of the emergency cut-off isolation device 2 is communicated with the discharge port of the second settling separator 21 in one way and communicated with the third feed port of the liquid seal scrubber 10 in the other way; The gas phase discharge port of the liquid seal scrubber 10 is communicated with the first feed port of the scrubbing tower 13; the gas phase discharge port of the scrubbing tower 13 is communicated with the feed port of the Roots blower 18 in one part and returned to the scrubbing tower 13 in the other part; the discharge port of the Roots blower 18 is respectively communicated with the feed ports of the heating furnace and the flare tank; The liquid phase discharge port of the scrubbing tower 13 is communicated with the feed port of the scrubbing tower circulating wash oil cooler 15.

[0028] The settling separator adopts a self-balancing line with a flame barrier to realize material import and export, so that the gas in the equipment can be freely balanced, thereby reducing oil gas emission and inert gas supplement, and preventing flame propagation; the system pressure is led to the liquid seal scrubber through the self-balancing line, and the liquid seal is performed through the liquid level, and the pressure can be controlled through the liquid level; when the pressure is greater than the liquid seal pressure, the gas is discharged through the liquid seal scrubber, the discharged gas is washed through the scrubbing tower, the washed gas enters the heating furnace through the Roots blower to be burned with the fuel gas, and the recovery treatment of light components is realized; meanwhile, each settling separator and liquid seal scrubber is provided with a nitrogen supplement pipeline and an emergency cut-off isolation device; in an emergency, the emergency cut-off isolation device can quickly close and block the material flow, the supplemental inert gas can dilute the combustible gas, and the system pressure balance and cut-off are realized through self-pressure balance. The present application can effectively solve the problems of environmental pollution caused by solvent storage light component volatilization, light component gas flash explosion risk, resource waste and the like.

[0029] According to the present application, optionally, the centrifuge 22 is provided with a feed pipeline, a feed valve is arranged on the feed pipeline, and the feed pipeline is connected to a conventional pressure reduction unit in the direct coal liquefaction pitch purification process system, and is used to feed the first light component generated by the conventional pressure reduction unit into the centrifuge.

[0030] According to the present application, optionally, the first settling separator 1 and the second settling separator 21 are respectively provided with a top liquid discharge pipeline, an intermediate liquid discharge pipeline and a bottom intermediate liquid discharge pipeline, the top liquid discharge pipeline, the intermediate liquid discharge pipeline and the bottom intermediate liquid discharge pipeline are respectively communicated with a top liquid tank, an intermediate liquid tank and a bottom intermediate liquid tank, a top liquid discharge valve 5 is arranged on the top liquid discharge pipeline, an intermediate liquid discharge valve 6 is arranged on the intermediate liquid discharge pipeline, and a bottom intermediate liquid discharge valve 7 is arranged on the bottom intermediate liquid discharge pipeline.

[0031] According to the present application, optionally, the first settling separator 1 and the second settling separator 21 are respectively provided with a feed pipeline, a feed valve 8 is arranged on the feed pipeline. The feed pipeline is connected to a conventional pressure reduction unit in the direct coal liquefaction pitch purification process system, and is used to feed the second light component generated by the conventional pressure reduction unit into the settling separator.

[0032] According to the present application, optionally, a balance valve 3 is arranged on the pipeline between the first settling separator 1 and the second settling separator 21. When the first settling separator is fed, the gas in the first settling separator is supplemented to the second settling separator which is discharged through the pipeline. In this way, the gas in the settling separator is supplemented to each other, which can effectively reduce the consumption of inert gas, thereby reducing the energy consumption of the device.

[0033] According to the present application, optionally, the first settling separator 1 and the second settling separator 21 are respectively provided with a first nitrogen supplement pipeline, and a first nitrogen supplement valve 4 is arranged on the first nitrogen supplement pipeline.

[0034] According to the present application, optionally, the liquid seal scrubber 10 is provided with a second nitrogen supplement pipeline, and a second nitrogen supplement valve 9 is arranged on the second nitrogen supplement pipeline. The first nitrogen supplement pipeline and the second nitrogen supplement pipeline can supplement the inert gas to dilute the combustible gas, thereby avoiding the risk of flash explosion of the light component gas.

[0035] According to the present application, optionally, a pressure control valve 12 is arranged on the pipeline between the gas phase discharge port of the scrubbing tower 13 and the first feed port of the scrubbing tower 13. The pressure control valve can control the pressure entering the scrubbing tower.

[0036] According to the present application, optionally, a scrubbing tower reflux control valve 14 is arranged on the pipeline between the liquid phase discharge port of the scrubbing tower 13 and the feed port of the scrubbing tower circulating wash oil cooler 15. The scrubbing tower reflux control valve can control the pressure of the liquid phase refluxing to the scrubbing tower.

[0037] According to the present application, optionally, a part of the discharge port of the scrubbing tower circulating wash oil cooler 15 is in communication with the feed port of the scrubbing tower circulating pump 17, and another part is sent out for recovery; the discharge port of the scrubbing tower circulating pump 17 is in communication with the second feed port of the scrubbing tower 13; a scrubbing tower circulating wash sending valve 16 is arranged on the pipeline of the discharge port of the scrubbing tower circulating wash oil cooler 15.

[0038] According to the present application, optionally, the discharge port of the Roots blower 18 is in communication with the fuel gas or combustion air feed port of the heating furnace.

[0039] According to the present application, optionally, a flare cut-off valve 20 is arranged on the pipeline between the discharge port of the Roots blower 18 and the feed port of the flare tank, and a gas sending valve 19 is arranged on the pipeline between the discharge port of the Roots blower 18 and the fuel gas or combustion air feed port.

[0040] Another aspect of the present application provides a method for recovering light components, which uses the system provided in the above-mentioned aspects of the present application, and the method comprises: The induced draft fan 23 induces the first light components from the exhaust port of the centrifuge 22 housing, and sends the first light components into the liquid seal scrubber 10 for first washing after being pressurized; The second light components are sent into the first settling separator 1 for separation, and the gaseous phase after separation is sent into the liquid seal scrubber 10 through the self-balancing line of the band-pass fire for second washing; The gaseous phase after the first washing and the second washing of the liquid seal scrubber 10 is sent into the scrubbing tower 13 for further washing, and the gaseous phase after washing is sent into the heating furnace or the flare tank through the Roots blower 18, and is burned with the fuel gas, combustion air or flare tank of the heating furnace.

[0041] According to the present application, optionally, the first light components are pressurized to 5-20 KPa.

[0042] According to the present application, optionally, the settling speed of the first settling separator 1 is about 0.23-0.3 m / h, and the separation time is 24-72 h.

[0043] According to the present application, optionally, the liquid seal pressure of the liquid seal scrubber 10 is 1-3 KPa.

[0044] According to the present application, optionally, the tower pressure of the scrubbing tower 13 is 0.2-2 KPa.

[0045] The method realizes the recovery treatment of light components, solves the problem of volatile emission of benzopyrene contained in the solvent, effectively prevents environmental pollution and safety risks, and is suitable for light component recovery treatment technology after solvent storage and solvent ultra-flash point operation high temperature volatilization of various scales, and has foresight, safety, economy and operability.

[0046] The application will be further illustrated by examples below, but the application is not limited in any way by the examples.

[0047] Example 1 This example provides a system for light component recovery treatment, referring to Figure 1 The system comprises a centrifuge 22, a suction fan 23, a first settling separator 1, a second settling separator 21, an emergency cut-off isolation device 2, a liquid seal scrubber 10, a liquid seal scrubber circulating pump 11, a scrubbing tower 13, a scrubbing tower circulating wash oil cooler 15, a scrubbing tower circulating pump 17, a Roots blower 18, a heating furnace and a flare tank. The casing exhaust port of the centrifuge 22 is in communication with the feed port of the suction fan 23; the discharge port of the suction fan 23 is in communication with the first feed port of the liquid seal scrubber 10; the liquid phase discharge port of the liquid seal scrubber 10 is in communication with the feed port of the liquid seal scrubber circulating pump 11; one part of the discharge port of the liquid seal scrubber liquid phase circulating pump 11 is in communication with the second feed port of the liquid seal scrubber 10, and the other part is sent back for recovery; thereby realizing solvent recovery and recycling; The first settling separator 1 and the second settling separator 21 are respectively provided with a top liquid discharge pipeline, an intermediate liquid discharge pipeline and a bottom intermediate liquid discharge pipeline, the top liquid discharge pipeline is provided with a top liquid discharge valve 5, the intermediate liquid discharge pipeline is provided with an intermediate liquid discharge valve 6, and the bottom intermediate liquid discharge pipeline is provided with a bottom intermediate liquid discharge valve 7; the first settling separator 1 and the second settling separator 21 are respectively provided with a feed pipeline, and the feed pipeline is provided with a feed valve 8; a balance valve 3 is arranged on the pipeline between the first settling separator 1 and the second settling separator 21; The gas phase discharge port of the first settling separator 1 is connected with a self-balancing line with a flame arrestor; the self-balancing line with a flame arrestor is provided with the emergency cut-off isolation device 2; the gas phase discharge port is in communication with the feed port of the emergency cut-off isolation device 2; one way of the discharge port of the emergency cut-off isolation device 2 is in communication with the discharge port of the second settling separator 21; and the other way is in communication with the third feed port of the liquid seal scrubber 10; The first settling separator 1 and the second settling separator 21 are respectively provided with a first nitrogen supplement pipeline, the first nitrogen supplement pipeline is provided with a first nitrogen supplement valve 4, the liquid seal scrubber 10 is provided with a second nitrogen supplement pipeline, and the second nitrogen supplement pipeline is provided with a second nitrogen supplement valve 9. The gas phase outlet of the liquid seal scrubber 10 is communicated with the first inlet of the scrubbing tower 13; the gas phase outlet of the scrubbing tower 13 is communicated with the inlet of the Roots blower 18 in part, and is returned to the scrubbing tower 13 in part; the pipeline between the gas phase outlet of the scrubbing tower 13 and the first inlet of the scrubbing tower 13 is provided with a pressure control valve 12; the outlet of the Roots blower 18 is communicated with the fuel gas or combustion air inlet of the heating furnace in part, and the pipeline between the outlet and the inlet is provided with a gas delivery valve 19; the other part is communicated with the flare tank inlet; the pipeline between the outlet and the inlet is provided with a flare cut-off valve 20; The liquid phase outlet of the scrubbing tower 13 is communicated with the inlet of the scrubbing tower circulating wash oil cooler 15; the pipeline between the liquid phase outlet and the inlet is provided with a scrubbing tower backflow control valve 14; The outlet of the scrubbing tower circulating wash oil cooler 15 is communicated with the inlet of the scrubbing tower circulating pump 17 in part, and is delivered for recovery in part; the outlet of the scrubbing tower circulating pump 17 is communicated with the second inlet of the scrubbing tower 13; the pipeline of the outlet of the scrubbing tower circulating wash oil cooler 15 is provided with a scrubbing tower circulating wash delivery valve 16.

[0048] Example 2 The present embodiment provides a method for recovering light components, which uses the system of Example 1, and takes a coal-based pitch separation and purification process of a certain coal chemical plant as an example. The specific method steps for recovering the light components produced by the solvent super flash point operation volatilization or high temperature cracking include: The first light component is drawn by the induced draft fan 23 at the exhaust port of the centrifuge 22 housing, and is sent into the liquid seal scrubber 10 for first washing after being boosted in pressure; The second light component is sent into the first settling separator 1 for separation, and the gas phase after separation is sent into the liquid seal scrubber 10 for second washing through the self balance line of the bandpass fire; wherein the settling speed of the first settling separator 1 is 0.23 m / h, and the separation time is 48 h; the liquid seal pressure of the liquid seal scrubber 10 is 2 KPa; The gas phase after the first washing and the second washing of the liquid seal scrubber 10 is sent into the scrubbing tower 13 for further washing, and the gas phase after washing is sent into the heating furnace through the Roots blower 18, and is combusted with the fuel gas of the heating furnace; wherein the tower pressure of the scrubbing tower 13 is 1 KPa.

[0049] The present embodiment effectively solves the problems of environmental pollution, light component gas flash explosion risk and light component recovery caused by solvent high temperature volatilization. The recovered light components can be used as the balance gas between equipment and equipment or as the fuel gas of the heating furnace, so as to reduce the energy consumption of the device, achieve zero emission and achieve the expected goal.

[0050] The preferred embodiments of the present application are described in detail above with reference to the drawings, but the present application is not limited to the specific details of the above-described embodiments. Various simple modifications can be made to the technical solutions of the present application within the technical concept of the present application, and these simple modifications all belong to the protection scope of the present application.

[0051] In addition, it should be noted that each specific technical feature described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, various possible combinations are not described again by the present application.

[0052] In addition, various different embodiments of the present application can also be combined in any appropriate manner, as long as they do not deviate from the idea of the present application, and they should also be considered as disclosed by the present application.

Claims

1. A system for recovering and processing light components, characterized in that, The system includes a centrifuge (22), an exhaust fan (23), a first sedimentation separator (1), a second sedimentation separator (21), an emergency shut-off isolation facility (2), a liquid seal scrubber (10), a liquid seal scrubber circulation pump (11), a scrubbing tower (13), a scrubbing tower circulating oil cooler (15), a scrubbing tower circulation pump (17), a Roots blower (18), a heating furnace, and a flare tank; The exhaust port of the centrifuge (22) is connected to the inlet of the exhaust fan (23); the outlet of the exhaust fan (23) is connected to the first inlet of the liquid seal scrubber (10); the liquid phase outlet of the liquid seal scrubber (10) is connected to the inlet of the liquid seal scrubber circulation pump (11); a portion of the outlet of the liquid phase circulation pump (11) of the liquid seal scrubber is connected to the second inlet of the liquid seal scrubber (10), and the other portion is sent out for recycling. The gas phase outlet of the first sedimentation separator (1) is connected to a self-balancing line with flame arrestor; the self-balancing line with flame arrestor is equipped with the emergency cut-off isolation facility (2); the gas phase outlet is connected to the inlet of the emergency cut-off isolation facility (2); one outlet of the emergency cut-off isolation facility (2) is connected to the outlet of the second sedimentation separator (21); the other outlet is connected to the third inlet of the liquid seal scrubber (10); The vapor discharge port of the liquid seal scrubber (10) is connected to the first feed port of the scrubbing tower (13); a portion of the vapor discharge port of the scrubbing tower (13) is connected to the feed port of the Roots blower (18), and the other portion returns to the scrubbing tower (13); the discharge port of the Roots blower (18) is connected to the feed ports of the heating furnace and the flare tank respectively; The liquid phase outlet of the washing tower (13) is connected to the inlet of the washing tower circulating oil cooler (15).

2. The system according to claim 1, wherein, The first sedimentation separator (1) and the second sedimentation separator (21) are respectively provided with a top liquid discharge pipeline, an intermediate liquid discharge pipeline and a bottom liquid discharge pipeline. A top liquid discharge valve (5) is provided on the top liquid discharge pipeline, an intermediate liquid discharge valve (6) is provided on the intermediate liquid discharge pipeline, and a bottom liquid discharge valve (7) is provided on the bottom liquid discharge pipeline. The first sedimentation separator (1) and the second sedimentation separator (21) are respectively provided with feed pipelines, and feed valves (8) are provided on the feed pipelines. A balancing valve (3) is installed on the pipeline between the first sedimentation separator (1) and the second sedimentation separator (21).

3. The system according to claim 2, wherein, The first sedimentation separator (1) and the second sedimentation separator (21) are respectively provided with a first nitrogen replenishment pipeline, and a first nitrogen replenishment valve (4) is provided on the first nitrogen replenishment pipeline.

4. The system according to claim 1, wherein, The liquid seal scrubber (10) is provided with a second nitrogen replenishment line, and a second nitrogen replenishment valve (9) is provided on the second nitrogen replenishment line.

5. The system according to claim 1, wherein, A pressure control valve (12) is installed on the pipeline between the gas phase outlet of the washing tower (13) and the first inlet of the washing tower (13).

6. The system according to claim 1, wherein, A washing tower reflux control valve (14) is installed on the pipeline between the liquid phase outlet of the washing tower (13) and the inlet of the washing tower circulating oil cooler (15).

7. The system according to claim 1, wherein, The discharge port of the washing tower circulating oil cooler (15) is connected to the inlet of the washing tower circulating pump (17), and the other part is sent out for recycling; the discharge port of the washing tower circulating pump (17) is connected to the second inlet of the washing tower (13). The outlet pipeline of the washing tower circulating washing oil cooler (15) is equipped with a washing tower circulating washing external valve (16).

8. The system according to claim 1, wherein, The outlet of the Roots blower (18) is connected to the fuel gas or combustion air inlet of the heating furnace; A flare shut-off valve (20) is installed on the pipeline between the outlet of the Roots blower (18) and the inlet of the flare tank, and a gas delivery valve (19) is installed on the pipeline between the outlet of the Roots blower (18) and the inlet of the fuel gas or combustion air.

9. A method for recovering and processing light components, characterized in that, The method employs the system described in any one of claims 1-8, and the method comprises: The exhaust fan (23) draws the first light component from the exhaust port of the centrifuge (22) casing, pressurizes the first light component and sends it into the liquid seal scrubber (10) for the first wash; The second light component is fed into the first settling separator (1) for separation. The separated gas phase is sent to the liquid seal scrubber (10) for second washing via a self-balancing line with flame arrestor. The gas phase after the first and second washing of the liquid seal scrubber (10) is sent to the scrubbing tower (13) for further washing. The washed gas phase is sent to the heating furnace or flare can by the Roots blower (18) and is burned together with the fuel gas, combustion air or flare can of the heating furnace.

10. The method according to claim 9, wherein, The first light component is pressurized to 5-20 kPa; The settling velocity of the first settling separator (1) is about 0.23-0.3 m / h, and the separation time is 24-72 h; The liquid seal pressure of the liquid seal scrubber (10) is 1-3 kPa; The pressure of the washing tower (13) is 0.2-2 kPa.

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