Flare gas pretreatment and recovery device and recovery treatment method

Abstract

The invention belongs to a flare gas pretreatment and recovery device and a recovery treatment method. Comprising a torch combustion device and a plurality of waste gas generation systems, waste gas pipelines of the waste gas generation systems are connected with a waste gas absorbing and recycling unit through a pretreatment unit, the waste gas absorbing and recycling unit is connected with a post-treatment circulating unit, and the post-treatment circulating unit is connected with the waste gas absorbing and recycling unit and the torch combustion device; the device has the characteristics of reasonable structural design, capability of effectively solving the problem of large operation load of a torch combustion device caused by large instantaneous flow and capability of reducing purchase and operation cost when a new project is put into use.

Description

Technical Field

[0001] The invention belongs to the technical field of waste gas treatment, and specifically relates to a flare gas pretreatment recovery device and a recovery treatment method. Background Art

[0002] In the complex system of industrial production, flare gas emission is an issue that deserves great attention. The flare was originally designed to safely handle the waste gas generated in the production process in an emergency or under specific process requirements, so as to achieve environmental friendliness; but in actual use, the flare device has the following problems: 1. The flare gas emission has the characteristics of instantaneous flow, and the instantaneous flow is huge; that is, when the flare device is operating normally, there will be a sudden increase in load, affecting the normal operation of the flare device; 2. The flare device has a certain operating load. When the project needs to be added, it is inevitable to redesign and purchase the flare device, which invisibly increases the commissioning cost. Summary of the invention

[0003] In order to make up for the above deficiencies, the present invention provides a flare gas pretreatment recovery device and a recovery treatment method to solve the technical problems existing in the prior art.

[0004] The technical solution adopted by the present invention to solve its technical problem is:

[0005] A flare gas pretreatment recovery device comprises a flare combustion device and several waste gas generating systems. The waste gas pipelines of the several waste gas generating systems are connected to a waste gas absorption and recycling unit through a pretreatment unit. The waste gas absorption and recycling unit is connected to a post-treatment circulation unit. The post-treatment circulation unit is respectively connected to the waste gas absorption and recycling unit and the flare combustion device.

[0006] The beneficial effects of the present invention are as follows: the present invention abandons the technical solution of directly connecting the exhaust gas pipeline to the flare combustion device in the traditional technology, and by setting a pretreatment unit, an exhaust gas absorption and recycling unit and a post-treatment circulation unit, not only can the effective components in the exhaust gas be recovered and reused, but the flow of the exhaust gas can also be extended to play a buffering role. Furthermore, by setting a exhaust gas absorption and recycling unit to reduce the amount of exhaust gas entering the flare combustion device, it is possible to use one flare combustion device to treat exhaust gas for multiple exhaust gas generating systems, thereby achieving the characteristic of saving equipment investment.

[0007] Preferably, a first pressure sensor is provided on the exhaust gas pipe; the pretreatment unit includes a first condenser, the exhaust gas pipe is connected to the first gas-liquid separation tank through the first heat exchange pipe of the first condenser, and the gas phase outlet of the first gas-liquid separation tank is respectively connected to the gas phase inlet and the gas phase outlet of the absorption tower in the exhaust gas absorption and recycling unit.

[0008] Preferably, the waste gas absorption and recycling unit includes an absorption tower. A gas phase inlet is provided in the middle and lower part of the absorption tower and is connected to a gas distributor at the lower part inside the absorption tower. A packing layer is provided in the middle part inside the absorption tower. A spray pipeline is provided at the top of the packing layer. A gas phase outlet is provided at the top of the absorption tower. The bottom of the absorption tower is connected to the spray pipeline through a circulation pump and a first three-way valve. The third end of the first three-way valve is connected to the recycling section.

[0009] Preferably, the post-treatment circulation unit includes a second condenser. The inlet of the first heat exchange pipeline of the second condenser is connected to the gas phase outlet of the absorption tower. The outlet of the first heat exchange pipeline of the second condenser is connected to a second gas-liquid separation tank. The gas phase outlet of the second gas-liquid separation tank is connected to a flare combustion device through a second three-way valve. The third end of the second three-way valve is connected to the gas phase inlet of the absorption tower through a circulation fan. A second pressure sensor is provided on the pipeline between the gas phase outlet of the second gas-liquid separation tank and the second three-way valve.

[0010] Preferably, the liquid phase outlets at the bottoms of the first gas-liquid separation tank and the second gas-liquid separation tank are respectively connected to the recycling section through corresponding pipelines.

[0011] Preferably, a first valve and a third three-way valve are sequentially provided between the third end of the second three-way valve and the inlet of the circulation fan. A fourth three-way valve and a second valve are sequentially provided between the first heat exchange pipeline of the first condenser and the first gas-liquid separation tank. A third valve is provided between the third three-way valve and the fourth three-way valve. The outlet of the circulation fan is connected to the gas phase inlet of the absorption tower through a fourth valve.

[0012] The present invention further includes a demineralized water pipeline. The demineralized water pipeline is sequentially connected to a deaerator through the second heat exchange pipeline of the second condenser and the second heat exchange pipeline of the first condenser.

[0013] Preferably, a fifth valve and a fifth three-way valve are provided between the first three-way valve and the spray pipeline. A sixth valve is provided between the third end of the first three-way valve and the recycling section. The demineralized water pipeline is connected to the third end of the fifth three-way valve through a seventh valve.

[0014] Preferably, an eighth valve is provided between the gas phase outlet of the first gas-liquid separation tank and the gas phase outlet of the absorption tower. A ninth valve is provided between the second three-way valve and the flare combustion device.

[0015] The present invention provides a recovery and treatment method for a flare gas pretreatment and recovery device. The recovery and treatment method includes the following steps:

[0016] Step 1: The waste gas generated by several waste gas generation systems respectively enters the waste gas pipeline. The first pressure sensor real-time monitors the pressure of the waste gas in the waste gas pipeline.

[0017] Step 2: When the pressure of the waste gas does not exceed the preset threshold, the waste gas in the waste gas pipeline is condensed in the first heat exchange pipeline of the first condenser, and after condensation, it enters the first gas-liquid separation tank for buffering and gas-liquid separation. The gas phase after gas-liquid separation enters the gas distributor in the absorption tower to make the gas phase evenly distributed, defoamed and absorbed. The unabsorbed gas phase rises to the packing layer and countercurrently contacts the absorption liquid from the spray pipeline to fully absorb the available components in the gas phase;

[0018] Step 3: The unabsorbed gas phase in the absorption tower enters the first heat exchange pipeline of the second condenser for further heat exchange and cooling, and after cooling, it enters the second gas-liquid separation tank for buffering and gas-liquid separation. When the gas phase passes through the second pressure sensor after gas-liquid separation, its pressure is detected. When the pressure meets the preset threshold, the gas phase enters the flare combustion device for combustion treatment;

[0019] Step 4: When the pressure of the waste gas exceeds the preset threshold, the waste gas in the waste gas pipeline is condensed in the first heat exchange pipeline of the first condenser, and after condensation, it enters the first gas-liquid separation tank for buffering and gas-liquid separation. Part of the gas phase after gas-liquid separation enters the absorption tower to absorb the gas, and the other part of the gas phase converges at the gas phase outlet of the absorption tower, mixes with the unabsorbed gas phase from the absorption tower and repeats Step 3 above;

[0020] Step 5: When the gas phase after gas-liquid separation passes through the second pressure sensor, its pressure is detected. When the pressure exceeds the preset threshold, part of the gas phase enters the flare combustion device for combustion treatment, and the other part of the gas phase enters the gas distributor in the absorption tower through the circulation fan for secondary absorption. The gas phase after secondary absorption repeats Step 3 above;

[0021] Step 6: When the pressure at the outlet of the first heat exchange pipeline of the first condenser in Step 2 exceeds the preset threshold, part of the material enters the first gas-liquid separation tank for gas-liquid separation and repeats Step 2 above; the other part of the material enters the gas distributor in the absorption tower through the circulation fan for absorption and repeats Step 3 above;

[0022] Step 7: The demineralized water in the demineralized water pipeline enters the deaerator for deaeration after passing through the second heat exchange pipeline of the second condenser and the second heat exchange pipeline of the first condenser, and is subsequently used as boiler feed water;

[0023] Step 8: The absorption liquid at the bottom of the absorption tower is sent to the recycling section through the circulation pump for recycling treatment. The liquid phases in the first gas-liquid separation tank and the second gas-liquid separation tank are respectively sent to the recycling section for recycling treatment;

[0024] Step 9: When the spray pipeline in Step 2 needs to spray the absorption liquid, turn on the circulation pump to send the absorption liquid at the bottom of the absorption tower into the spray pipeline. When the amount of the absorption liquid at the bottom of the absorption tower is insufficient, the demineralized water in the brine pipeline enters the spray pipeline through the seventh valve and the third end of the fifth three-way joint.

[0025] A flare gas pretreatment and recovery device and a recovery and treatment method made according to the above technical solution can achieve the condensation and buffering of waste gas by setting a pretreatment unit, which can not only reduce the treatment load of the waste gas absorption and reuse unit, but also effectively solve the problem of large instantaneous flow rate of flare gas emissions; by setting a waste gas absorption and reuse unit, not only can the valuable part of the waste gas be recovered and reused, but also the amount of waste gas entering the flare combustion device can be reduced, so as to achieve the purpose of enabling a flare combustion device to treat the waste gas generated by multiple waste gas generation systems; by setting a post-treatment circulation unit, the waste gas can be further treated, which can not only avoid the problem of the waste gas carrying liquid affecting the operation of the flare combustion device, but also effectively extend the waste gas treatment process, fully recover the effective components in the waste gas, and also has the characteristic of enabling the flare combustion device to operate stably for a long time; based on the characteristics of the waste gas generated by the waste gas generation system, the present invention sets a first pressure sensor and a second pressure sensor. By setting the first pressure sensor, the pressure in the waste gas pipeline can be detected in real time, and different process routes can be selected according to the pressure conditions to achieve the stable operation of the whole system on the premise of avoiding the overloading operation of the waste gas absorption and reuse unit. By setting the second pressure sensor, the condition of the waste gas before entering the flare combustion device can be monitored in real time, and the process route can be adjusted according to the pressure to achieve the stable operation of the flare combustion device; in the present invention, the amount of the waste gas entering the waste gas absorption and reuse unit is adjusted based on the data of the first pressure sensor, and at the same time, the amount of the waste gas entering the flare combustion device is adjusted based on the data of the second pressure sensor to achieve the stable operation of the whole system; it has the characteristics of reasonable structure design, being able to effectively solve the problem of large operation load of the flare combustion device caused by large instantaneous flow rate, and reducing the purchase and operation costs when new projects are put into operation. Brief Description of the Drawings

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0027] Figure 1 It is a structural schematic diagram of the present invention.

[0028] In the figure: 1. Torch combustion device; 2. Waste gas generation system; 3. First pressure sensor; 4. First condenser; 5. First gas-liquid separation tank; 6. Absorption tower; 7. Gas distributor; 8. Packing layer; 9. Spray pipeline; 10. Circulation pump; 11. Recycling section; 12. Second condenser; 13. Second gas-liquid separation tank; 14. Circulation fan; 15. Second pressure sensor; 16. Desalted water pipeline; 17. Deaerator; 18. First three-way joint; 19. Second three-way joint; 20. Third three-way joint; 21. Fourth three-way joint; 22. Fifth three-way joint; 23. First valve; 24. Second valve; 25. Third valve; 26. Fourth valve; 27. Fifth valve; 28. Sixth valve; 29. Seventh valve; 30. Eighth valve; 31. Ninth valve. Detailed implementation manners

[0029] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0030] The following combines the attached Figure 1The present application will be further described in detail. The present invention relates to a flare gas pretreatment and recovery device and a recovery and treatment method. The treatment and recovery device includes a flare combustion device 1, a plurality of waste gas generation systems 2. The waste gas pipelines of the plurality of waste gas generation systems 2 are connected to a waste gas absorption and reuse unit through a pretreatment unit. The waste gas absorption and reuse unit is connected to a post-treatment circulation unit. The post-treatment circulation unit is respectively connected to the waste gas absorption and reuse unit and the flare combustion device 1. Due to the setting of the pretreatment unit, the waste gas absorption and reuse unit, and the post-treatment circulation unit, the present invention can realize the recycling of waste gas, and at the same time can reduce the waste gas treatment volume of the flare combustion device 1. Meanwhile, by extending the process flow between the waste gas pipeline and the flare combustion device 1, the waste gas can be buffered, so that one flare combustion device 1 can treat the waste gas generated by multiple waste gas generation systems 2; in the present invention, the pretreatment unit is mainly used for preliminarily condensing and buffering the waste gas to reduce the treatment load of the waste gas absorption and reuse unit and avoid a large amount of gas phase entering the waste gas absorption and reuse unit, resulting in the abnormal operation of the waste gas absorption and reuse unit; the waste gas absorption and reuse unit is used for recovering the effective components in the waste gas, which not only realizes the cost reduction of the operation of other sections, but also can reduce the waste gas treatment volume of the flare combustion device 1; the post-treatment circulation unit can not only realize the deep condensation and buffering of the gas phase to avoid the problem of incomplete combustion of the flare combustion device 1 caused by liquid entrainment in the gas phase and reduce the gas phase treatment volume of the flare combustion device 1, but also can extend the gas phase process route when the gas phase volume is too large, and fully recycle the recyclable components in the gas phase on the basis of the stable operation of the flare combustion device 1.

[0031] Further, a first pressure sensor 3 is provided on the waste gas pipeline; the pretreatment unit includes a first condenser 4. The waste gas pipeline is connected to a first gas-liquid separation tank 5 through a first heat exchange pipeline of the first condenser 4. The gas phase outlet of the first gas-liquid separation tank 5 is respectively connected to the gas phase inlet of an absorption tower 6 in the waste gas absorption and reuse unit and the gas phase outlet of the absorption tower 6. In the present invention, the first pressure sensor 3 is used to detect the pressure of the waste gas in the waste gas pipeline in real time and adjust the process route of the waste gas according to the pressure to meet the stable operation of the whole system; the first condenser 4 in the present invention can condense the gases in the waste gas that are easy to liquefy, thereby reducing the treatment load in the subsequent waste gas absorption and reuse unit. Further, it can reduce the activity of gas molecules in the waste gas and prepare for the absorption in the subsequent stage; by setting the first gas-liquid separation tank 5, not only can the gas-liquid separation of the liquid condensed in the first condenser 4 be realized, but also the gas volume absorbed in the waste gas absorption and reuse unit can be stabilized. At the same time, by connecting the gas phase outlet of the first gas-liquid separation tank 5 to the gas phase outlet of the absorption tower 6, it can be ensured that when the first gas-liquid separation tank 5 is over-pressured, the back pressure of the subsequent flare emission system does not exceed the standard.

[0032] Further, the waste gas absorption and reuse unit includes an absorption tower 6. A gas phase inlet is provided in the middle and lower part of the absorption tower 6 and is connected to a gas distributor 7 at the lower part inside the absorption tower 6. A packing layer 8 is provided in the middle of the absorption tower 6. A spraying pipeline 9 is provided at the top of the packing layer 8. A gas phase outlet is provided at the top of the absorption tower 6. The bottom of the absorption tower 6 is connected to the spraying pipeline 9 through a circulation pump 10 and a first three-way valve 18. The third end of the first three-way valve 18 is connected to a reuse section 11. In the present invention, the absorption tower 6 is used to absorb the reusable components in the waste gas. Preferably, there are two packing layers 8, and a spraying pipeline 9 is provided at the top of each packing layer 8. The lower part of the absorption tower 6 is the absorption liquid, and the absorption liquid can be sent into the spraying pipeline 9 through the circulation pump 10 for circulating spraying or sent into the reuse section 11 to realize the recycling and reuse of the absorption liquid. The gas distributor 7 is arranged below the liquid level of the absorption liquid at the lower part of the absorption tower 6. The waste gas is evenly distributed through the gas distributor 7, and at the same time, the contact area between the bubble breaking and the absorption liquid is increased, so as to improve the absorption efficiency of the available components. Further, the unabsorbed gas phase contacts the spraying liquid flowing from top to bottom in a countercurrent manner to realize secondary absorption, so as to fully absorb the effective components in the waste gas.

[0033] Further, the post-treatment circulation unit includes a second condenser 12. The first heat exchange pipeline inlet of the second condenser 12 is connected to the gas phase outlet of the absorption tower 6. The first heat exchange pipeline outlet of the second condenser 12 is connected to a second gas-liquid separation tank 13. The gas phase outlet of the second gas-liquid separation tank 13 is connected to the flare combustion device 1 through a second three-way valve 19. The third end of the second three-way valve 19 is connected to the gas phase inlet of the absorption tower 6 through a circulation fan 14. A second pressure sensor 15 is provided on the pipeline between the gas phase outlet of the second gas-liquid separation tank 13 and the second three-way valve 19. By setting the second condenser 12 in the present invention, the solvent carried out in the previous section can be recovered, which can not only reduce the gas phase entering the subsequent section, but also help to reduce the liquid in the gas phase. At the same time, it can also reduce the gas temperature at the gas phase outlet of the absorption tower 6 to realize the increase of the gas rising rate. Further, by setting the second gas-liquid separation tank 13, the liquid phase from the second condenser 12 can be separated to avoid the problem of incomplete combustion of the flare combustion device 1 caused by liquid carried by the gas phase, thereby improving the service life of the flare combustion device 1.

[0034] Further, the liquid phase outlets at the bottoms of the first gas-liquid separation tank 5 and the second gas-liquid separation tank 13 are respectively connected to the reuse section 11 through corresponding pipelines. Through the above settings, the effective recycling and reuse of the available components in the waste gas can be realized.

[0035] Further, a first valve 23 and a third three-way pipe 20 are sequentially arranged between the third end of the second three-way pipe 19 and the inlet of the circulation fan 14, which is connected to the inlet of the circulation fan 14; through the above arrangement, the pressure in the torch combustion device 1 can be avoided from being too high, and at the same time, the process route of the gas phase can be extended to effectively recycle and reuse the available components in the gas phase; a fourth three-way pipe 21 and a second valve 24 are sequentially arranged between the first heat exchange pipe of the first condenser 4 and the first gas-liquid separation tank 5, and a third valve 25 is arranged between the third three-way pipe 20 and the fourth three-way pipe 21; the outlet of the circulation fan 14 is connected to the gas phase inlet of the absorption tower 6 through a fourth valve 26; through the foregoing arrangement, the pressure in the first gas-liquid separation tank 5 can be avoided from being too high, thereby affecting the stable operation of the entire system.

[0036] The present invention further includes a desalted water pipe 16, and the desalted water pipe 16 is sequentially connected to the deaerator 17 through the second heat exchange pipe of the second condenser 13 and the second heat exchange pipe of the first condenser 4. By arranging the heat exchange cooperation between the desalted water pipe 16 and the condenser, the present invention can effectively utilize the heat energy in the waste gas to achieve the characteristic of saving the energy consumption of boiler feed water.

[0037] Further, a fifth valve 27 and a fifth three-way pipe 22 are arranged between the first three-way pipe 18 and the spray pipe 9, a sixth valve 28 is arranged between the third end of the first three-way pipe 18 and the recycling section 11, and the desalted water pipe 16 is connected to the third end of the fifth three-way pipe 22 through a seventh valve 29. The desalted water in the desalted water pipe 16 can not only be used for the recovery and utilization of heat energy, but also be used as the supplementary liquid of the absorption liquid.

[0038] Further, an eighth valve 30 is arranged between the gas phase outlet of the first gas-liquid separation tank 5 and the gas phase outlet of the absorption tower 6, and a ninth valve 31 is arranged between the second three-way pipe 19 and the torch combustion device 1.

[0039] The present invention also provides a recovery treatment method for a torch gas pretreatment recovery device, and the recovery treatment method includes the following steps:

[0040] Step 1: The waste gas generated by several waste gas generation systems 2 respectively enters the waste gas pipe, and the first pressure sensor 3 monitors the pressure of the waste gas in the waste gas pipe in real time;

[0041] Step 2: When the pressure of the waste gas does not exceed the preset threshold, the waste gas in the waste gas pipe is condensed in the first heat exchange pipe of the first condenser 4, and after condensation, it enters the first gas-liquid separation tank 5 for buffering and gas-liquid separation. The gas phase after gas-liquid separation enters the gas distributor 7 in the absorption tower 6 to make the gas phase evenly distributed, defoamed and absorbed. The unabsorbed gas phase rises to the packing layer 8 and countercurrently contacts the absorption liquid from the spray pipe 9 to fully absorb the available components in the gas phase;

[0042] Step 3: The unabsorbed gas phase in the absorption tower 6 enters the first heat exchange pipeline of the second condenser 12 for further heat exchange and cooling. After cooling, it enters the second gas-liquid separation tank 13 for buffering and gas-liquid separation. When the gas phase passes through the second pressure sensor 15 after gas-liquid separation, its pressure is detected. When the pressure meets the preset threshold, the gas phase enters the flare combustion device 1 for combustion treatment;

[0043] Step 4: When the pressure of the waste gas exceeds the preset threshold, the waste gas in the waste gas pipeline is condensed in the first heat exchange pipeline of the first condenser 4. After condensation, it enters the first gas-liquid separation tank 5 for buffering and gas-liquid separation. Part of the gas phase after gas-liquid separation enters the absorption tower 6 to absorb the gas, and the other part of the gas phase converges to the gas phase outlet of the absorption tower 6, mixes with the unabsorbed gas phase from the absorption tower 6, and repeats the above Step 3;

[0044] Step 5: When the gas phase after gas-liquid separation passes through the second pressure sensor 15, its pressure is detected. When the pressure exceeds the preset threshold, part of the gas phase enters the flare combustion device 1 for combustion treatment, and the other part of the gas phase enters the gas distributor 7 in the absorption tower 6 through the circulation fan 14 for secondary absorption. The gas phase after secondary absorption repeats the above Step 3;

[0045] Step 6: When the pressure at the outlet of the first heat exchange pipeline of the first condenser 4 in Step 2 exceeds the preset threshold, part of the material enters the first gas-liquid separation tank 5 for gas-liquid separation and repeats the above Step 2; the other part of the material enters the gas distributor 7 in the absorption tower 6 through the circulation fan 14 for absorption and repeats the above Step 3;

[0046] Step 7: The demineralized water in the demineralized water pipeline 16 passes through the second heat exchange pipeline of the second condenser 13 and the second heat exchange pipeline of the first condenser 4 and then enters the deaerator 17 for deaeration, and is subsequently used as boiler feed water;

[0047] Step 8: The absorption liquid at the bottom of the absorption tower 6 is sent to the recycling section 11 through the circulation pump 10 for recycling treatment. The liquid phases in the first gas-liquid separation tank 5 and the second gas-liquid separation tank 13 are respectively sent to the recycling section 11 for recycling treatment;

[0048] Step 9: When the absorption liquid needs to be sprayed in the spray pipeline 9 in Step 2, the circulation pump 10 is turned on to send the absorption liquid at the bottom of the absorption tower 6 into the spray pipeline 9. When the amount of the absorption liquid at the bottom of the absorption tower 6 is insufficient, the demineralized water in the demineralized water pipeline 16 enters the spray pipeline 9 through the third end of the seventh valve 29 and the fifth three-way pipe 22.

[0049] The present invention can treat the exhaust gas generated in a plurality of exhaust gas generation systems 2. The treatment can include the treatment when the exhaust gas generation systems 2 generate exhaust gas separately or when exhaust gas is generated centrally. During a release, the exhaust gas first enters the first condenser 4 for condensation and then enters the first gas-liquid separation tank 5 for buffer collection (if the pressure exceeds the safety threshold, it will be released through the eighth valve 30 to ensure the safety and stability of the system). After gas-liquid separation in the first gas-liquid separation tank 5, the liquid phase is recycled and reused, and the gas phase is absorbed through the absorption tower 6. Due to the instantaneous increase in pipeline pressure caused by the release, pressure detection is carried out through the first pressure sensor 3, the circulation pump 10 is started to make the absorption liquid at the bottom of the absorption tower 6 enter the recycling section 11, and at the same time, the seventh valve 29 is opened to make the demineralized water in the brine pipeline 16 enter the spray pipeline 9 to prevent solution saturation and reduce the absorption efficiency, so as to maximize the solvent absorption and ensure that the flare gas is absorbed as much as possible. The absorbed solution is sent to subsequent separation and purification devices for treatment. In the present invention, after the absorption, condensation, and separation of the exhaust gas, the circulation fan 14 is started according to the pressure at the second pressure sensor 15, so that the gas is sent to the absorption tower 6 for reabsorption after pressurization, which increases the system capacity and further improves the absorption efficiency. Further, when the pressure of the first pressure sensor 3 is too high, the third valve 25 can be opened to quickly reduce the gas pressure and send it to the absorption tower 6 for treatment to ensure the stability and safety of the system. The plurality of exhaust gas generation systems 2 described in the present invention can include a methylamine device, an ammonia storage tank area, an ammonia synthesis area, etc., and can recover components such as ammonia and methylamine in the tail gas, and carry out treatment and absorption before entering the flare combustion device 1, and then send it to the recycling section 11 (the recycling section 11 can be a methylamine device) for recovery; or the exhaust gas generation system 2 can include the discharge of shifted acid gas, the discharge of acid gas from a methanol washing device, the discharge of acid gas from a sulfur recovery unit, and accidentally released acid gas. After being absorbed by methanol, it is slowly sent to the recycling section 11 (the recycling section 11 can be a methanol washing section) for recovery.Furthermore, the preset thresholds of the first pressure sensor 3 and the second pressure sensor 15 in the present invention can be adjusted according to the actual production situation. For example, when the preset threshold of the first pressure sensor 3 is 0.4 MPa and the preset threshold of the second pressure sensor 15 is 0.3 MPa, and the measured pressure of the first pressure sensor 3 is less than 0.4 MPa and the measured pressure of the second pressure sensor 15 is less than 0.3 MPa, the operation mode of Embodiment 1 below can be adopted; when the measured pressure of the first pressure sensor 3 is greater than 0.4 MPa and less than 0.5 MPa and the measured pressure of the second pressure sensor 15 is less than 0.3 MPa, the operation mode of Embodiment 2 below can be adopted; when the measured pressure of the first pressure sensor 3 is greater than 0.4 MPa and less than 0.5 MPa and the measured pressure of the second pressure sensor 15 is greater than 0.3 MPa, the operation mode of Embodiment 3 below can be adopted; when the measured pressure of the first pressure sensor 3 is greater than 0.5 MPa and the measured pressure of the second pressure sensor 15 is greater than 0.3 MPa, the operation mode of Embodiment 4 below can be adopted.

[0050] To explain the present invention in more detail, the present invention will be further described below in conjunction with embodiments. The specific embodiments are as follows:

[0051] Embodiment 1

[0052] A flare gas pretreatment and recovery device includes a flare combustion device 1, several waste gas generation systems 2. The waste gas pipelines of several waste gas generation systems 2 are connected to a waste gas absorption and reuse unit through a pretreatment unit. The waste gas absorption and reuse unit is connected to a post-treatment circulation unit, and the post-treatment circulation unit is respectively connected to the waste gas absorption and reuse unit and the flare combustion device 1. A first pressure sensor 3 is provided on the waste gas pipeline; the pretreatment unit includes a first condenser 4. The waste gas pipeline is connected to a first gas-liquid separation tank 5 through a first heat exchange pipeline of the first condenser 4. The gas phase outlet of the first gas-liquid separation tank 5 is respectively connected to the gas phase inlet of an absorption tower 6 in the waste gas absorption and reuse unit and the gas phase outlet of the absorption tower 6. The waste gas absorption and reuse unit includes the absorption tower 6. A gas phase inlet is provided in the middle and lower part of the absorption tower 6 and is connected to a gas distributor 7 in the lower part of the absorption tower 6. A packing layer 8 is provided in the middle of the absorption tower 6. A spraying pipeline 9 is provided at the top of the packing layer 8. A gas phase outlet is provided at the top of the absorption tower 6; the bottom of the absorption tower 6 is connected to the spraying pipeline 9 through a circulation pump 10 and a first three-way valve 18. The third end of the first three-way valve 18 is connected to a reuse section 11. The post-treatment circulation unit includes a second condenser 12. The inlet of the first heat exchange pipeline of the second condenser 12 is connected to the gas phase outlet of the absorption tower 6. The outlet of the first heat exchange pipeline of the second condenser 12 is connected to a second gas-liquid separation tank 13. The gas phase outlet of the second gas-liquid separation tank 13 is connected to the flare combustion device 1 through a second three-way valve 19. The third end of the second three-way valve 19 is connected to the gas phase inlet of the absorption tower 6 through a circulation fan 14; a second pressure sensor 15 is provided on the pipeline between the gas phase outlet of the second gas-liquid separation tank 13 and the second three-way valve 19. The liquid phase outlets at the bottoms of the first gas-liquid separation tank 5 and the second gas-liquid separation tank 13 are respectively connected to the reuse section 11 through corresponding pipelines. A first valve 23 and a third three-way valve 20 are sequentially provided between the third end of the second three-way valve 19 and the inlet of the circulation fan 14; a fourth three-way valve 21 and a second valve 24 are sequentially provided between the first heat exchange pipeline of the first condenser 4 and the first gas-liquid separation tank 5. A third valve 25 is provided between the third three-way valve 20 and the fourth three-way valve 21; the outlet of the circulation fan 14 is connected to the gas phase inlet of the absorption tower 6 through a fourth valve 26. The present invention also includes a desalted water pipeline 16. The desalted water pipeline 16 is sequentially connected to a deaerator 17 through a second heat exchange pipeline of the second condenser 13 and a second heat exchange pipeline of the first condenser 4. A fifth valve 27 and a fifth three-way valve 22 are provided between the first three-way valve 18 and the spraying pipeline 9. A sixth valve 28 is provided between the third end of the first three-way valve 18 and the reuse section 11. The desalted water pipeline 16 is connected to the third end of the fifth three-way valve 22 through a seventh valve 29. An eighth valve 30 is provided between the gas phase outlet of the first gas-liquid separation tank 5 and the gas phase outlet of the absorption tower 6. A ninth valve 31 is provided between the second three-way valve 19 and the flare combustion device 1.

[0053] The present invention also provides a recovery treatment method for a flare gas pretreatment recovery device, and the recovery treatment method includes the following steps:

[0054] Step 1: The waste gas generated by several waste gas generation systems 2 respectively enters the waste gas pipeline, and the first pressure sensor 3 monitors the pressure of the waste gas in the waste gas pipeline in real time;

[0055] Step 2: When the pressure of the waste gas does not exceed the preset threshold value, the waste gas in the waste gas pipeline is condensed in the first heat exchange pipeline of the first condenser 4, and after condensation, it enters the first gas-liquid separation tank 5 for buffering and gas-liquid separation. The gas phase after gas-liquid separation enters the gas distributor 7 in the absorption tower 6 to make the gas phase evenly distributed, defoamed and absorbed. The unabsorbed gas phase rises to the packing layer 8 and makes countercurrent contact with the absorption liquid from the spray pipeline 9 to fully absorb the available components in the gas phase;

[0056] Step 3: The unabsorbed gas phase in the absorption tower 6 enters the first heat exchange pipeline of the second condenser 12 for further heat exchange and cooling, and after cooling, it enters the second gas-liquid separation tank 13 for buffering and gas-liquid separation. When the gas phase passes through the second pressure sensor 15, its pressure is detected. When the pressure meets the preset threshold value, the gas phase enters the flare combustion device 1 for combustion treatment.

[0057] Step 4: The demineralized water in the demineralized water pipeline 16 passes through the second heat exchange pipeline of the second condenser 13 and the second heat exchange pipeline of the first condenser 4 and then enters the deaerator 17 for deaeration, and is subsequently used as boiler water;

[0058] Step 5: The absorption liquid at the bottom of the absorption tower 6 is sent to the recycling section 11 through the circulating pump 10 for recovery treatment, and the liquid phases in the first gas-liquid separation tank 5 and the second gas-liquid separation tank 13 are respectively sent to the recycling section 11 for recovery treatment;

[0059] Step 6: When the absorption liquid needs to be sprayed in the spray pipeline 9 in Step 2, the circulating pump 10 is started to send the absorption liquid at the bottom of the absorption tower 6 into the spray pipeline 9. When the amount of the absorption liquid at the bottom of the absorption tower 6 is insufficient, the demineralized water in the demineralized water pipeline 16 enters the spray pipeline 9 through the third end of the seventh valve 29 and the fifth three-way pipe 22.

[0060] Example 2

[0061] A flare gas pretreatment and recovery device includes a flare combustion device 1, several waste gas generation systems 2. The waste gas pipelines of several waste gas generation systems 2 are connected to a waste gas absorption and reuse unit through a pretreatment unit. The waste gas absorption and reuse unit is connected to a post-treatment circulation unit, and the post-treatment circulation unit is respectively connected to the waste gas absorption and reuse unit and the flare combustion device 1. A first pressure sensor 3 is provided on the waste gas pipeline; the pretreatment unit includes a first condenser 4. The waste gas pipeline is connected to a first gas-liquid separation tank 5 through a first heat exchange pipeline of the first condenser 4. The gas phase outlet of the first gas-liquid separation tank 5 is respectively connected to the gas phase inlet of an absorption tower 6 in the waste gas absorption and reuse unit and the gas phase outlet of the absorption tower 6. The waste gas absorption and reuse unit includes the absorption tower 6. A gas phase inlet is provided in the middle and lower part of the absorption tower 6 and is connected to a gas distributor 7 in the lower part of the absorption tower 6. A packing layer 8 is provided in the middle of the absorption tower 6. A spraying pipeline 9 is provided at the top of the packing layer 8. A gas phase outlet is provided at the top of the absorption tower 6; the bottom of the absorption tower 6 is connected to the spraying pipeline 9 through a circulation pump 10 and a first three-way valve 18. The third end of the first three-way valve 18 is connected to a reuse section 11. The post-treatment circulation unit includes a second condenser 12. The inlet of the first heat exchange pipeline of the second condenser 12 is connected to the gas phase outlet of the absorption tower 6. The outlet of the first heat exchange pipeline of the second condenser 12 is connected to a second gas-liquid separation tank 13. The gas phase outlet of the second gas-liquid separation tank 13 is connected to the flare combustion device 1 through a second three-way valve 19. The third end of the second three-way valve 19 is connected to the gas phase inlet of the absorption tower 6 through a circulation fan 14; a second pressure sensor 15 is provided on the pipeline between the gas phase outlet of the second gas-liquid separation tank 13 and the second three-way valve 19. The liquid phase outlets at the bottoms of the first gas-liquid separation tank 5 and the second gas-liquid separation tank 13 are respectively connected to the reuse section 11 through corresponding pipelines. A first valve 23 and a third three-way valve 20 are sequentially provided between the third end of the second three-way valve 19 and are connected to the inlet of the circulation fan 14; a fourth three-way valve 21 and a second valve 24 are sequentially provided between the first heat exchange pipeline of the first condenser 4 and the first gas-liquid separation tank 5. A third valve 25 is provided between the third three-way valve 20 and the fourth three-way valve 21; the outlet of the circulation fan 14 is connected to the gas phase inlet of the absorption tower 6 through a fourth valve 26. The present invention further includes a desalted water pipeline 16. The desalted water pipeline 16 is sequentially connected to a deaerator 17 through a second heat exchange pipeline of the second condenser 13 and a second heat exchange pipeline of the first condenser 4. A fifth valve 27 and a fifth three-way valve 22 are provided between the first three-way valve 18 and the spraying pipeline 9. A sixth valve 28 is provided between the third end of the first three-way valve 18 and the reuse section 11. The desalted water pipeline 16 is connected to the third end of the fifth three-way valve 22 through a seventh valve 29. An eighth valve 30 is provided between the gas phase outlet of the first gas-liquid separation tank 5 and the gas phase outlet of the absorption tower 6. A ninth valve 31 is provided between the second three-way valve 19 and the flare combustion device 1.

[0062] The present invention also provides a recovery and treatment method for a flare gas pretreatment and recovery device. The recovery and treatment method includes the following steps:

[0063] Step 1: The waste gas produced by several waste gas generation systems 2 enters the waste gas pipeline respectively, and the first pressure sensor 3 monitors the pressure of the waste gas in the waste gas pipeline in real time.

[0064] Step 2: When the pressure of the waste gas exceeds the preset threshold, the waste gas in the waste gas pipeline is condensed in the first heat exchange pipeline of the first condenser 4, and after condensation, it enters the first gas-liquid separation tank 5 for buffering and gas-liquid separation. A part of the gas phase after gas-liquid separation enters the absorption tower 6 to absorb the gas, and another part of the gas phase converges to the gas phase outlet of the absorption tower 6 and is mixed with the unabsorbed gas phase from the absorption tower 6; the gas phase after the above-mentioned gas-liquid separation enters the gas distributor 7 in the absorption tower 6 to make the gas phase evenly distributed, defoamed and absorbed. The unabsorbed gas phase rises to the packing layer 8 and contacts the absorption liquid from the spray pipeline 9 in a countercurrent manner to fully absorb the available components in the gas phase.

[0065] Step 3: The mixed gas phase enters the first heat exchange pipeline of the second condenser 12 for further heat exchange and cooling, and after cooling, it enters the second gas-liquid separation tank 13 for buffering and gas-liquid separation. When the gas phase passes through the second pressure sensor 15 after gas-liquid separation, its pressure is detected. When the pressure meets the preset threshold, the gas phase enters the flare combustion device 1 for combustion treatment.

[0066] Step 4: The demineralized water in the demineralized water pipeline 16 passes through the second heat exchange pipeline of the second condenser 13 and the second heat exchange pipeline of the first condenser 4 and then enters the deaerator 17 for deaeration, and is subsequently used as boiler water.

[0067] Step 5: The absorption liquid at the bottom of the absorption tower 6 is sent to the recycling section 11 through the circulation pump 10 for recovery treatment, and the liquid phases in the first gas-liquid separation tank 5 and the second gas-liquid separation tank 13 are respectively sent to the recycling section 11 for recovery treatment.

[0068] Step 6: When the absorption liquid needs to be sprayed in the spray pipeline 9 in Step 2, the circulation pump 10 is turned on to send the absorption liquid at the bottom of the absorption tower 6 into the spray pipeline 9. When the amount of the absorption liquid at the bottom of the absorption tower 6 is insufficient, the demineralized water in the demineralized water pipeline 16 enters the spray pipeline 9 through the third end of the seventh valve 29 and the fifth three-way pipe 22.

[0069] Example 3

[0070] A flare gas pretreatment and recovery device includes a flare combustion device 1, several waste gas generation systems 2. The waste gas pipelines of several waste gas generation systems 2 are connected to a waste gas absorption and reuse unit through a pretreatment unit. The waste gas absorption and reuse unit is connected to a post-treatment circulation unit, and the post-treatment circulation unit is respectively connected to the waste gas absorption and reuse unit and the flare combustion device 1. A first pressure sensor 3 is provided on the waste gas pipeline; the pretreatment unit includes a first condenser 4. The waste gas pipeline is connected to a first gas-liquid separation tank 5 through a first heat exchange pipeline of the first condenser 4. The gas phase outlet of the first gas-liquid separation tank 5 is respectively connected to the gas phase inlet of an absorption tower 6 in the waste gas absorption and reuse unit and the gas phase outlet of the absorption tower 6. The waste gas absorption and reuse unit includes the absorption tower 6. A gas phase inlet is provided in the middle and lower part of the absorption tower 6 and is connected to a gas distributor 7 at the lower part inside the absorption tower 6. A packing layer 8 is provided in the middle of the absorption tower 6. A spraying pipeline 9 is provided at the top of the packing layer 8. A gas phase outlet is provided at the top of the absorption tower 6; the bottom of the absorption tower 6 is connected to the spraying pipeline 9 through a circulation pump 10 and a first three-way valve 18. The third end of the first three-way valve 18 is connected to a recycling section 11. The post-treatment circulation unit includes a second condenser 12. The inlet of the first heat exchange pipeline of the second condenser 12 is connected to the gas phase outlet of the absorption tower 6. The outlet of the first heat exchange pipeline of the second condenser 12 is connected to a second gas-liquid separation tank 13. The gas phase outlet of the second gas-liquid separation tank 13 is connected to the flare combustion device 1 through a second three-way valve 19. The third end of the second three-way valve 19 is connected to the gas phase inlet of the absorption tower 6 through a circulation fan 14; a second pressure sensor 15 is provided on the pipeline between the gas phase outlet of the second gas-liquid separation tank 13 and the second three-way valve 19. The liquid phase outlets at the bottoms of the first gas-liquid separation tank 5 and the second gas-liquid separation tank 13 are respectively connected to the recycling section 11 through corresponding pipelines. A first valve 23 and a third three-way valve 20 are successively provided between the third end of the second three-way valve 19 and connected to the inlet of the circulation fan 14; a fourth three-way valve 21 and a second valve 24 are successively provided between the first heat exchange pipeline of the first condenser 4 and the first gas-liquid separation tank 5. A third valve 25 is provided between the third three-way valve 20 and the fourth three-way valve 21; the outlet of the circulation fan 14 is connected to the gas phase inlet of the absorption tower 6 through a fourth valve 26. The present invention further includes a desalted water pipeline 16. The desalted water pipeline 16 is successively connected to a deaerator 17 through a second heat exchange pipeline of the second condenser 13 and a second heat exchange pipeline of the first condenser 4. A fifth valve 27 and a fifth three-way valve 22 are provided between the first three-way valve 18 and the spraying pipeline 9. A sixth valve 28 is provided between the third end of the first three-way valve 18 and the recycling section 11. The desalted water pipeline 16 is connected to the third end of the fifth three-way valve 22 through a seventh valve 29. An eighth valve 30 is provided between the gas phase outlet of the first gas-liquid separation tank 5 and the gas phase outlet of the absorption tower 6. A ninth valve 31 is provided between the second three-way valve 19 and the flare combustion device 1.

[0071] The present invention also provides a recovery and treatment method for a flare gas pretreatment and recovery device, and the recovery and treatment method includes the following steps:

[0072] Step 1: The waste gas generated by several waste gas generation systems 2 respectively enters the waste gas pipeline, and the first pressure sensor 3 monitors the pressure of the waste gas in the waste gas pipeline in real time;

[0073] Step 2: When the pressure of the waste gas exceeds the preset threshold, the waste gas in the waste gas pipeline is condensed in the first heat exchange pipeline of the first condenser 4, and after condensation, it enters the first gas-liquid separation tank 5 for buffering and gas-liquid separation. A part of the gas phase after gas-liquid separation enters the absorption tower 6 to absorb the gas, and another part of the gas phase converges to the gas phase outlet of the absorption tower 6 and is mixed with the unabsorbed gas phase from the absorption tower 6; the gas phase after the above-mentioned gas-liquid separation enters the gas distributor 7 in the absorption tower 6 to make the gas phase evenly distributed, defoamed and absorbed. The unabsorbed gas phase rises to the packing layer 8 and contacts countercurrently with the absorption liquid from the spray pipeline 9 to fully absorb the available components in the gas phase;

[0074] Step 3: The mixed gas phase enters the first heat exchange pipeline of the second condenser 12 for further heat exchange and cooling, and after cooling, it enters the second gas-liquid separation tank 13 for buffering and gas-liquid separation. When the gas phase after gas-liquid separation passes through the second pressure sensor 15, its pressure is detected;

[0075] Step 4: When the gas phase after gas-liquid separation passes through the second pressure sensor 15, its pressure is detected. When the pressure exceeds the preset threshold, a part of the gas phase enters the flare combustion device 1 for combustion treatment, and another part of the gas phase enters the gas distributor 7 in the absorption tower 6 through the circulation fan 14 for secondary absorption, and the gas phase after secondary absorption repeats the above Step 3;

[0076] Step 5: The desalted water in the desalted water pipeline 16 enters the deaerator 17 through the second heat exchange pipeline of the second condenser 13 and the second heat exchange pipeline of the first condenser 4 for deaeration, and is subsequently used as boiler water;

[0077] Step 6: The absorption liquid at the bottom of the absorption tower 6 is sent to the recycling section 11 through the circulation pump 10 for recovery treatment, and the liquid phases in the first gas-liquid separation tank 5 and the second gas-liquid separation tank 13 are respectively sent to the recycling section 11 for recovery treatment;

[0078] Step 7: When the absorption liquid needs to be sprayed in the spray pipeline 9 in Step 2, the circulation pump 10 is turned on to send the absorption liquid at the bottom of the absorption tower 6 into the spray pipeline 9. When the amount of the absorption liquid at the bottom of the absorption tower 6 is insufficient, the desalted water in the desalted water pipeline 16 enters the spray pipeline 9 through the third end of the seventh valve 29 and the fifth three-way 22.

[0079] Example 4

[0080] A flare gas pretreatment and recovery device includes a flare combustion device 1, several waste gas generation systems 2. The waste gas pipelines of several waste gas generation systems 2 are connected to a waste gas absorption and reuse unit through a pretreatment unit. The waste gas absorption and reuse unit is connected to a post-treatment circulation unit, and the post-treatment circulation unit is respectively connected to the waste gas absorption and reuse unit and the flare combustion device 1. A first pressure sensor 3 is provided on the waste gas pipeline; the pretreatment unit includes a first condenser 4. The waste gas pipeline is connected to a first gas-liquid separation tank 5 through a first heat exchange pipeline of the first condenser 4. The gas phase outlet of the first gas-liquid separation tank 5 is respectively connected to the gas phase inlet of an absorption tower 6 in the waste gas absorption and reuse unit and the gas phase outlet of the absorption tower 6. The waste gas absorption and reuse unit includes an absorption tower 6. A gas phase inlet is provided in the middle and lower part of the absorption tower 6 and is connected to a gas distributor 7 at the lower part inside the absorption tower 6. A packing layer 8 is provided in the middle of the absorption tower 6. A spray pipeline 9 is provided at the top of the packing layer 8. A gas phase outlet is provided at the top of the absorption tower 6; the bottom of the absorption tower 6 is connected to the spray pipeline 9 through a circulation pump 10 and a first three-way valve 18. The third end of the first three-way valve 18 is connected to a reuse section 11. The post-treatment circulation unit includes a second condenser 12. The inlet of the first heat exchange pipeline of the second condenser 12 is connected to the gas phase outlet of the absorption tower 6. The outlet of the first heat exchange pipeline of the second condenser 12 is connected to a second gas-liquid separation tank 13. The gas phase outlet of the second gas-liquid separation tank 13 is connected to the flare combustion device 1 through a second three-way valve 19. The third end of the second three-way valve 19 is connected to the gas phase inlet of the absorption tower 6 through a circulation fan 14; a second pressure sensor 15 is provided on the pipeline between the gas phase outlet of the second gas-liquid separation tank 13 and the second three-way valve 19. The liquid phase outlets at the bottoms of the first gas-liquid separation tank 5 and the second gas-liquid separation tank 13 are respectively connected to the reuse section 11 through corresponding pipelines. A first valve 23 and a third three-way valve 20 are successively provided between the third end of the second three-way valve 19 and connected to the inlet of the circulation fan 14; a fourth three-way valve 21 and a second valve 24 are successively provided between the first heat exchange pipeline of the first condenser 4 and the first gas-liquid separation tank 5. A third valve 25 is provided between the third three-way valve 20 and the fourth three-way valve 21; the outlet of the circulation fan 14 is connected to the gas phase inlet of the absorption tower 6 through a fourth valve 26. The present invention further includes a desalted water pipeline 16. The desalted water pipeline 16 is successively connected to a deaerator 17 through a second heat exchange pipeline of the second condenser 13 and a second heat exchange pipeline of the first condenser 4. A fifth valve 27 and a fifth three-way valve 22 are provided between the first three-way valve 18 and the spray pipeline 9. A sixth valve 28 is provided between the third end of the first three-way valve 18 and the reuse section 11. The desalted water pipeline 16 is connected to the third end of the fifth three-way valve 22 through a seventh valve 29. An eighth valve 30 is provided between the gas phase outlet of the first gas-liquid separation tank 5 and the gas phase outlet of the absorption tower 6. A ninth valve 31 is provided between the second three-way valve 19 and the flare combustion device 1.

[0081] The present invention also provides a recovery and treatment method for a flare gas pretreatment and recovery device, and the recovery and treatment method includes the following steps:

[0082] Step 1: The waste gas generated by several waste gas generation systems 2 respectively enters the waste gas pipeline, and the first pressure sensor 3 monitors the pressure of the waste gas in the waste gas pipeline in real time;

[0083] Step 2: When the pressure of the waste gas exceeds a preset threshold value, the waste gas in the waste gas pipeline is condensed in the first heat exchange pipeline of the first condenser 4. After condensation, a part of the material enters the first gas-liquid separation tank 5 for gas-liquid separation, and another part of the material enters the gas distributor 7 in the absorption tower 6 through the circulation fan 14 for absorption; for the material that enters the first gas-liquid separation tank 5 for buffering and gas-liquid separation, another part of the material and a part of the gas phase after gas-liquid separation enter the absorption tower 6 to absorb the gas, and another part of the gas phase converges to the gas phase outlet of the absorption tower 6 and is mixed with the unabsorbed gas phase from the absorption tower 6; the absorption process is as follows: the gas phase enters the gas distributor 7 in the absorption tower 6 to make the gas phase evenly distributed, defoamed and absorbed. The unabsorbed gas phase rises to the packing layer 8 and makes countercurrent contact with the absorption liquid from the spray pipeline 9 to fully absorb the available components in the gas phase;

[0084] Step 3: The mixed gas phase enters the first heat exchange pipeline of the second condenser 12 for further heat exchange and cooling, and after cooling, it enters the second gas-liquid separation tank 13 for buffering and gas-liquid separation. When the gas phase after gas-liquid separation passes through the second pressure sensor 15, its pressure is detected;

[0085] Step 4: When the gas phase after gas-liquid separation passes through the second pressure sensor 15, its pressure is detected. When the pressure exceeds the preset threshold value, a part of the gas phase enters the flare combustion device 1 for combustion treatment, and another part of the gas phase enters the gas distributor 7 in the absorption tower 6 through the circulation fan 14 for secondary absorption. The gas phase after secondary absorption repeats the above Step 3;

[0086] Step 5: The desalted water in the desalted water pipeline 16 enters the deaerator 17 through the second heat exchange pipeline of the second condenser 13 and the second heat exchange pipeline of the first condenser 4 for deaeration, and is subsequently used as boiler water;

[0087] Step 6: The absorption liquid at the bottom of the absorption tower 6 is sent to the recycling section 11 through the circulation pump 10 for recovery treatment, and the liquid phases in the first gas-liquid separation tank 5 and the second gas-liquid separation tank 13 are respectively sent to the recycling section 11 for recovery treatment;

[0088] Step 7: When the spray pipe 9 in Step 2 needs to spray the absorption liquid, turn on the circulation pump 10 to send the absorption liquid at the bottom of the absorption tower 6 into the spray pipe 9. When the amount of the absorption liquid at the bottom of the absorption tower 6 is insufficient, the demineralized water in the brine pipe 16 enters the spray pipe 9 through the seventh valve 29 and the third end of the fifth three-way pipe 22.

[0089] The foregoing has shown and described the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments, and what is described in the above embodiments and the specification is only to illustrate the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will also have various changes and improvements, and these changes and improvements fall within the scope of the present invention claimed.

Claims

1. A flare gas pretreatment and recovery device, including a flare combustion device (1), characterized in that: A number of waste gas generation systems (2), the waste gas pipelines of the number of waste gas generation systems (2) are connected to the waste gas absorption and reuse unit through a pretreatment unit, the waste gas absorption and reuse unit is connected to the post-treatment circulation unit, and the post-treatment circulation unit is respectively connected to the waste gas absorption and reuse unit and the flare combustion device (1).

2. The pretreatment and recovery device for flare gas according to claim 1, wherein: A first pressure sensor (3) is provided on the waste gas pipeline; The pretreatment unit includes a first condenser (4), the waste gas pipeline is connected to a first gas-liquid separation tank (5) through a first heat exchange pipeline of the first condenser (4), and the gas phase outlet of the first gas-liquid separation tank (5) is respectively connected to the gas phase inlet and the gas phase outlet of the absorption tower (6) in the waste gas absorption and reuse unit.

3. The pretreating and recycling device for flare gas according to claim 2, wherein: The waste gas absorption and reuse unit includes an absorption tower (6), a gas phase inlet is provided in the middle and lower part of the absorption tower (6) and is connected to a gas distributor (7) in the lower part of the absorption tower (6), a packing layer (8) is provided in the middle of the absorption tower (6), a spray pipeline (9) is provided at the top of the packing layer (8), and a gas phase outlet is provided at the top of the absorption tower (6); the bottom of the absorption tower (6) is connected to the spray pipeline (9) through a circulation pump (10) and a first three-way joint (18), and the third end of the first three-way joint (18) is connected to the reuse section (11).

4. The pretreating and recycling device for flare gas according to claim 3, characterized in that: The post-treatment circulation unit includes a second condenser (12), the inlet of the first heat exchange pipeline of the second condenser (12) is connected to the gas phase outlet of the absorption tower (6), the outlet of the first heat exchange pipeline of the second condenser (12) is connected to a second gas-liquid separation tank (13), the gas phase outlet of the second gas-liquid separation tank (13) is connected to the flare combustion device (1) through a second three-way joint (19), and the third end of the second three-way joint (19) is connected to the gas phase inlet of the absorption tower (6) through a circulation fan (14); a second pressure sensor (15) is provided on the pipeline between the gas phase outlet of the second gas-liquid separation tank (13) and the second three-way joint (19).

5. The pretreating and recycling device for flare gas according to claim 4, wherein: The liquid phase outlets at the bottoms of the first gas-liquid separation tank (5) and the second gas-liquid separation tank (13) are respectively connected to the reuse section (11) through corresponding pipelines.

6. A flare gas pretreatment and recovery device according to claim 4, characterized in that: A first valve (23) and a third three-way joint (20) are sequentially provided between the third end of the second three-way joint (19) and the inlet of the circulation fan (14); A fourth three-way joint (21) and a second valve (24) are sequentially provided between the first heat exchange pipeline of the first condenser (4) and the first gas-liquid separation tank (5), and a third valve (25) is provided between the third three-way joint (20) and the fourth three-way joint (21); The outlet of the circulation fan (14) is connected to the gas phase inlet of the absorption tower (6) through a fourth valve (26).

7. A flare gas pretreatment and recovery device according to claim 4, characterized in that: It further includes a desalted water pipeline (16), and the desalted water pipeline (16) is sequentially connected to a deaerator (17) through a second heat exchange pipeline of the second condenser (13) and a second heat exchange pipeline of the first condenser (4).

8. The pretreatment and recovery device for flare gas according to claim 7, wherein: A fifth valve (27) and a fifth tee (22) are provided between the first tee (18) and the spray pipe (9). A sixth valve (28) is provided between the third end of the first tee (18) and the recycling section (11). The demineralized water pipe (16) is connected to the third end of the fifth tee (22) through a seventh valve (29).

9. A flare gas pretreatment and recovery device according to claim 4, characterized in that: An eighth valve (30) is provided between the gas phase outlet of the first gas-liquid separation tank (5) and the gas phase outlet of the absorption tower (6). A ninth valve (31) is provided between the second tee (19) and the flare combustion device (1).

10. A recovery and treatment method for a flare gas pretreatment and recovery device, characterized in that: The recovery and treatment method comprises the following steps: Step 1: The waste gas generated by a plurality of waste gas generation systems (2) respectively enters the waste gas pipe. The first pressure sensor (3) monitors the pressure of the waste gas in the waste gas pipe in real time. Step 2: When the pressure of the waste gas does not exceed a preset threshold value, the waste gas in the waste gas pipe is condensed in the first heat exchange pipe of the first condenser (4), and after condensation, it enters the first gas-liquid separation tank (5) for buffering and gas-liquid separation. The gas phase after gas-liquid separation enters the gas distributor (7) in the absorption tower (6) to make the gas phase evenly distributed, defoamed and absorbed. The unabsorbed gas phase ascends to the packing layer (8) and makes countercurrent contact with the absorption liquid from the spray pipe (9) to fully absorb the available components in the gas phase. Step 3: The unabsorbed gas phase in the absorption tower (6) enters the first heat exchange pipe of the second condenser (12) for further heat exchange and cooling, and after cooling, it enters the second gas-liquid separation tank (13) for buffering and gas-liquid separation. When the gas phase after gas-liquid separation passes through the second pressure sensor (15), its pressure is detected. When the pressure meets the preset threshold value, the gas phase enters the flare combustion device (1) for combustion treatment. Step 4: When the pressure of the waste gas exceeds the preset threshold value, the waste gas in the waste gas pipe is condensed in the first heat exchange pipe of the first condenser (4), and after condensation, it enters the first gas-liquid separation tank (5) for buffering and gas-liquid separation. A part of the gas phase after gas-liquid separation enters the absorption tower (6) to absorb the gas, and the other part of the gas phase converges at the gas phase outlet of the absorption tower (6), mixes with the unabsorbed gas phase from the absorption tower (6) and repeats the above Step 3. Step 5: When the gas phase after gas-liquid separation passes through the second pressure sensor (15), its pressure is detected. When the pressure exceeds the preset threshold value, a part of the gas phase enters the flare combustion device (1) for combustion treatment, and the other part of the gas phase enters the gas distributor (7) in the absorption tower (6) through the circulation fan (14) for secondary absorption. The gas phase after secondary absorption repeats the above Step 3. Step 6: When the pressure at the outlet of the first heat exchange pipe of the first condenser (4) in Step 2 exceeds the preset threshold value, a part of the material enters the first gas-liquid separation tank (5) for gas-liquid separation and repeats the above Step 2; the other part of the material enters the gas distributor (7) in the absorption tower (6) through the circulation fan (14) for absorption and repeats the above Step 3. Step 7: The demineralized water in the demineralized water pipeline (16) enters the deaerator (17) for deaeration after passing through the second heat exchange pipeline of the second condenser (13) and the second heat exchange pipeline of the first condenser (4), and is subsequently used as boiler feed water; Step 8: The absorption liquid at the bottom of the absorption tower (6) is sent to the recycling section (11) through the circulation pump (10) for recycling treatment, and the liquid phases in the first gas-liquid separation tank (5) and the second gas-liquid separation tank (13) are respectively sent to the recycling section (11) for recycling treatment; Step 9: When the absorption liquid needs to be sprayed in the spray pipeline (9) in Step 2, the circulation pump (10) is turned on to send the absorption liquid at the bottom of the absorption tower (6) into the spray pipeline (9). When the amount of the absorption liquid at the bottom of the absorption tower (6) is insufficient, the demineralized water in the brine pipeline (16) enters the spray pipeline (9) through the seventh valve (29) and the third end of the fifth three-way joint (22).

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