Flare gas recycling system

Abstract

The invention discloses a flare gas recycling system. A high-temperature side inlet of a first seawater cooler is connected with a gas phase outlet of a flare liquid separation tank, a low-temperature side inlet of the first seawater cooler is connected with a seawater system pipeline, a low-temperature side outlet of the first seawater cooler is connected with a sea discharge pipeline, and a high-temperature side outlet of the first seawater cooler is connected with an inlet of a liquid ring compressor; a high-temperature side inlet of the second seawater cooler is connected with a liquid phase outlet of the separator, a high-temperature side outlet is connected with a high-temperature side outlet of the first seawater cooler, a low-temperature side inlet is connected with a seawater system pipeline, and a low-temperature side outlet is connected with a sea discharge pipeline; an outlet of the liquid ring compressor is connected with an inlet of the separator; and a gas phase outlet of the separator is connected with a fuel gas system. Gas obtained after treatment of the torch liquid separation tank is cooled, pressurized and separated and then conveyed to a user, carbon emission is reduced, and the resource utilization rate is increased; and by arranging the second seawater cooler, the product at the liquid phase outlet of the separator is recycled and conveyed to the annular liquid type compressor for compression, and the resource utilization rate is increased to the maximum extent.

Description

Technical Field

[0001] The invention relates to the technical field of natural gas recovery, in particular to a flare gas recovery and reuse system. Background Art

[0002] Natural gas is an important product of offshore oil and gas fields. Whether it is oil field associated gas or gas field development gas, the produced natural gas needs to be transported to land terminals for deep processing and sales. Most offshore platforms are equipped with flare systems, which burn natural gas that cannot be transported and processed and is released due to platform process fluctuations every year. At the same time, large amounts of gas combustion can easily cause certain dangers to on-site personnel who are close to the flare head. Summary of the invention

[0003] In order to solve the above technical problems, the present invention adopts the following technical solutions: a flare gas recovery and reuse system, comprising a flare liquid separator, a liquid recovery module connected to the liquid phase outlet of the flare liquid separator, a safety pressure regulating module and a gas recovery module connected to the gas phase outlet of the flare liquid separator, and a plasma ignition torch connected to the safety pressure regulating module, wherein the safety pressure regulating module and the gas recovery module are arranged in parallel, and the gas recovery module comprises a first seawater cooler, a second seawater cooler, a liquid ring compressor and a separator;

[0004] The high temperature side inlet of the first seawater cooler is connected to the gas phase outlet of the flare liquid separator, the low temperature side inlet is connected to the seawater system pipeline, the low temperature side outlet is connected to the sea discharge pipeline, and the high temperature side outlet is connected to the inlet of the liquid ring compressor;

[0005] The high temperature side inlet of the second seawater cooler is connected to the liquid phase outlet of the separator, the high temperature side outlet is connected to the high temperature side outlet of the first seawater cooler, the low temperature side inlet is connected to the seawater system pipeline, and the low temperature side outlet is connected to the sea discharge pipeline;

[0006] The outlet of the liquid ring compressor is connected to the inlet of the separator;

[0007] The gas phase outlet of the separator is connected to the fuel gas system.

[0008] Furthermore, the gas recovery module also includes a first regulating valve arranged at the low temperature side outlet of the first seawater cooler and a first temperature transmitter arranged at the high temperature side outlet of the first seawater cooler, and the first temperature transmitter can control the opening of the first regulating valve.

[0009] Furthermore, the gas phase outlet of the separator is also connected to the high temperature side inlet of the first seawater cooler through a first bypass line.

[0010] Furthermore, the gas recovery module also includes a second regulating valve disposed on the first bypass pipeline and a first pressure transmitter disposed at the inlet of the liquid ring compressor, and the first pressure transmitter can adjust the opening of the second regulating valve.

[0011] Furthermore, the gas recovery module also includes a third regulating valve arranged at the liquid phase outlet of the separator and a first liquid level controller arranged on the separator, and the first liquid level controller can adjust the opening of the third regulating valve.

[0012] Furthermore, the gas recovery module also includes a fourth regulating valve arranged at the low temperature side outlet of the second seawater cooler and a second temperature transmitter arranged at the high temperature side outlet of the second seawater cooler, and the second temperature transmitter can control the opening of the fourth regulating valve.

[0013] Furthermore, the liquid recovery module includes a filter connected to the flare liquid separation tank and a canned discharge pump connected to the filter.

[0014] Furthermore, the liquid recovery module also includes a second liquid level transmitter arranged on the flare liquid separation tank, and the second liquid level transmitter can control the start and stop of the canned discharge pump.

[0015] Furthermore, the safety pressure regulating module includes a pressure regulating valve, a fast switching valve, a bursting disc and a second bypass pipeline with a valve which are arranged in parallel.

[0016] Furthermore, it also includes a second pressure transmitter arranged on the flare liquid separator tank, and the second pressure transmitter can control the start and stop of the liquid ring compressor.

[0017] The beneficial effects of the present invention are embodied in:

[0018] The flare gas recovery and reuse system of the present invention is provided with a gas recovery module, and the gas obtained after being treated by the flare liquid separator is cooled, pressurized, separated and distributed, and then transported to the fuel gas system for gas supply to users, thereby reducing carbon emissions and increasing resource utilization. During the distribution treatment, a second seawater cooler is provided, and the product at the liquid phase outlet of the separator is recovered and transported to the ring liquid compressor for compression, thereby maximizing resource utilization. The entire recovery process can be processed step by step without gas drainage, and has a wide range of applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the flare gas recovery and reuse system of the present invention;

[0020] The components in the attached drawings are marked as follows: 1. torch liquid separation tank; 2. liquid recovery module; 21. filter; 22. canned discharge pump; 23. second liquid level transmitter; 3. safety pressure regulating module; 31. pressure regulating valve; 32. fast switching valve; 33. bursting disc; 34. second bypass pipeline; 35. second pressure transmitter; 4. gas recovery module; 40. first seawater cooler; 41. second seawater cooler; 42. liquid ring compressor; 43. separator; 44. first regulating valve; 45. first temperature transmitter; 46. second regulating valve; 47. first pressure transmitter; 48. third regulating valve; 49. first liquid level controller; 410. fourth regulating valve; 411. second temperature transmitter; 5. first bypass pipeline; 6. second pressure transmitter; 7. plasma immediately ignites the torch. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. In the absence of conflict, the embodiments in this application and the features in the embodiments can be combined with each other. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0022] See also Figure 1 .

[0023] The flare gas recovery and reuse system of the present invention comprises a flare liquid separator 1, a liquid recovery module 2 connected to the liquid phase outlet of the flare liquid separator 1, a safety pressure regulating module 3 and a gas recovery module 4 connected to the gas phase outlet of the flare liquid separator 1, and a plasma ignition torch 5 connected to the safety pressure regulating module 3, wherein the safety pressure regulating module 3 and the gas recovery module 4 are arranged in parallel, and the gas recovery module 4 comprises a first seawater cooler 40, a second seawater cooler 41, a liquid ring compressor 42 and a separator 43;

[0024] The high temperature side inlet of the first seawater cooler 40 is connected to the gas phase outlet of the flare liquid separator 1, the low temperature side inlet is connected to the seawater system pipeline, the low temperature side outlet is connected to the sea discharge pipeline, and the high temperature side outlet is connected to the inlet of the liquid ring compressor 42;

[0025] The high temperature side inlet of the second seawater cooler 41 is connected to the liquid phase outlet of the separator 43, the high temperature side outlet is connected to the high temperature side outlet of the first seawater cooler 40, the low temperature side inlet is connected to the seawater system pipeline, and the low temperature side outlet is connected to the sea discharge pipeline;

[0026] The outlet of the liquid ring compressor 42 is connected to the inlet of the separator 43;

[0027] The gas phase outlet of the separator 43 is connected to the fuel gas system.

[0028] The flare gas recovery and reuse system of the present invention is provided with a gas recovery module 4, and the gas obtained after being processed by the flare liquid separator 1 is cooled, pressurized, separated and distributed, and then transported to the fuel gas system for gas supply to users, thereby reducing carbon emissions and increasing resource utilization. During the distribution process, a second seawater cooler 41 is provided, and the product at the liquid phase outlet of the separator 43 is recovered and transported to the ring liquid compressor 42 for compression, thereby maximizing the resource utilization. The entire recovery process can be processed step by step without gas drainage, and has a wide range of applications.

[0029] It should be noted that the flare separator tank 1 also has a discharge inlet and a heat medium inlet / outlet. The discharge inlet is connected to the discharge inlet manifold to receive the logistics discharged from the discharge manifold. The heat medium inlet and outlet are both liquid T55, which is used to maintain the temperature in the tank and prevent the liquid from solidifying.

[0030] In one embodiment, the gas recovery module 4 further includes a first regulating valve 44 disposed at the low temperature side outlet of the first seawater cooler 40 and a first temperature transmitter 45 disposed at the high temperature side outlet of the first seawater cooler 40, and the first temperature transmitter 45 can control the opening of the first regulating valve 44. In this design, the first temperature transmitter 45 controls the opening of the first regulating valve 44 by monitoring the temperature of the recovered gas cooled by seawater, thereby ensuring that the cooled recovered gas can enter the liquid ring compressor 42 by changing the heat exchange time.

[0031] In one embodiment, the gas phase outlet of the separator 43 is also connected to the high temperature side inlet of the first seawater cooler 40 through the first bypass line 5. This design can ensure that the refluxed gas (i.e. the cooled low temperature gas) is preferentially mixed with the gas entering the gas recovery module 4, and the power of the first seawater cooler 40 can be reduced to a certain extent.

[0032] In one embodiment, the gas recovery module 4 further includes a second regulating valve 46 disposed on the first bypass line 5 and a first pressure transmitter 47 disposed at the inlet of the liquid ring compressor 42, and the first pressure transmitter 47 can adjust the opening of the second regulating valve 46. In this design, the separator 43 performs gas-liquid separation, and the separated gas goes to the fuel gas system through the gas phase outlet, and finally flows into the liquid ring compressor 42 through the first bypass line 5. The first pressure transmitter 47 adjusts the opening of the second regulating valve 46 by monitoring the pressure at the inlet of the liquid ring compressor 42, thereby adjusting the amount of gas refluxed from the gas phase outlet of the separator 43 to the inlet of the liquid ring compressor 42, so as to maintain the pressure stability at the inlet of the liquid ring compressor 42.

[0033] In one embodiment, the gas recovery module 4 further includes a third regulating valve 48 disposed at the liquid phase outlet of the separator 43 and a first liquid level controller 49 disposed on the separator 43, and the first liquid level controller 49 can adjust the opening of the third regulating valve 48. In this design, the first liquid level controller 49 controls the third regulating valve 48 of the liquid phase outlet pipeline by monitoring the liquid level of the separator 43 to control the liquid level, thereby ensuring the stability of the liquid level of the separator 43, and the liquid phase outlet pipeline of the separator 43 is connected to the closed discharge system, and the third regulating valve 48 is disposed on the pipeline.

[0034] In one embodiment, the gas recovery module 4 further includes a fourth regulating valve 410 disposed at the low temperature side outlet of the second seawater cooler 41 and a second temperature transmitter 411 disposed at the high temperature side outlet of the second seawater cooler 41, and the second temperature transmitter 411 can control the opening of the fourth regulating valve 410. In this design, the second temperature transmitter 411 controls the opening of the fourth regulating valve 410 by monitoring the temperature of the recovered gas cooled by seawater, thereby ensuring that the cooled recovered gas can enter the liquid ring compressor 42 by changing the heat exchange time.

[0035] In one embodiment, the liquid recovery module 2 includes a filter 21 connected to the flare separation tank 1 and a canned discharge pump 22 connected to the filter 21. In this design, the liquid separated by the flare separation tank 1 enters the filter 21 from the tank bottom liquid phase outlet pipeline to filter impurities and then enters the canned discharge pump 22 to be pressurized and transported to the crude oil process.

[0036] In one embodiment, the liquid recovery module 2 further includes a second liquid level transmitter 23 disposed on the flare liquid separation tank 1, and the second liquid level transmitter 23 can control the start and stop of the tank discharge pump 22. In this design, the second liquid level transmitter 23 transmits a signal to the discharge pump 22 according to the tank liquid level to control the start and stop of the pump to ensure stable operation.

[0037] In one embodiment, the safety pressure regulating module 3 includes a pressure regulating valve 31, a quick switch valve 32, a bursting disc 33 and a second bypass line 34 with a valve arranged in parallel. It should be noted that the pressure setting point of the pressure regulating valve 31 is less than the quick switch valve 32 and less than the bursting disc 33 setting point, which ensures the safe and stable operation of the flare gas recovery process. The design is as follows: 1) when the gas intake of the flare liquid separation tank 1 suddenly increases and the flow rate of the quick opening valve 32 cannot meet the process pressure relief, the equipment pressure continues to rise at this time, and after reaching the set pressure of the bursting disc 33, the bursting disc 33 is blasted to increase the discharge volume to achieve the purpose of process pressure relief; 2) when the pressure of the flare liquid separation tank 1 increases, but the quick opening valve 32 fails to open, the equipment pressure continues to rise, and after reaching the pressure of the bursting disc 33, the bursting disc 33 is used to increase the discharge volume to achieve the purpose of process pressure relief. When the gas flow is too large to be recovered, the pressure breaks through the plasma and ignites the internal structure of the torch 7, thereby igniting and releasing;

[0038] When the pressure regulating valve 31 needs to be repaired or replaced, the ball valves on both sides of the pressure regulating valve 31 can be closed and the ball valve of the bypass pipeline 5 can be opened at the same time to ensure the normal operation of the flare separator 1. The quick opening valve 32 and the bursting disc 33 are the same and will not be repeated.

[0039] In one embodiment, the safety pressure regulating module 3 further includes a second pressure transmitter 35 capable of adjusting the opening of the pressure regulating valve 2. In this design, the pressure signal of the flare liquid separation tank 1 is collected by the second pressure transmitter 35 and transmitted to the pressure regulating valve 2 through the signal line, and the pressure regulating valve 2 adjusts the opening according to the pressure signal to ensure safe operation.

[0040] In one embodiment, it also includes a second pressure transmitter 6 disposed on the flare liquid separator 1, and the second pressure transmitter 6 can control the start and stop of the liquid ring compressor 42. In this design, the pressure of the flare liquid separator 1 is monitored by the second pressure transmitter 6. When the pressure is significantly higher or lower than the pressure range of normal operation, the second pressure transmitter 6 transmits the pressure signal to the liquid ring compressor 42 to shut it down to stop the recovery process. If it is overpressure, the overpressure gas will be transported to the plasma by pressure and then ignite the torch 7 for combustion. If it is underpressure, it is necessary to find out the cause on site and stabilize the pressure of the flare liquid separator before starting the recovery gas process automatically.

[0041] It should be understood that the examples and implementation modes described herein are for illustrative purposes only and are not intended to limit the present invention. Those skilled in the art may make various modifications or changes based on the examples and implementation modes. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

[0042] It should be noted that if the embodiments of the present invention involve directional indications such as up, down, left, right, front, back, etc., then the directional indications are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture as shown in the accompanying drawings. If the specific posture changes, the directional indication will also change accordingly.

[0043] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the meaning of "and / or" appearing in the full text includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or schemes that A and B meet at the same time. In addition, "multiple" refers to more than two. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

Claims

1. A flare gas recovery and reuse system, comprising a flare liquid separator (1), a liquid recovery module (2) connected to the liquid phase outlet of the flare liquid separator (1), a safety pressure regulating module (3) and a gas recovery module (4) connected to the gas phase outlet of the flare liquid separator (1), and a plasma ignition torch (7) connected to the safety pressure regulating module (3), wherein the safety pressure regulating module (3) and the gas recovery module (4) are arranged in parallel, characterized in that: The gas recovery module (4) comprises a first seawater cooler (40), a second seawater cooler (41), a liquid ring compressor (42) and a separator (43); The high temperature side inlet of the first seawater cooler (40) is connected to the gas phase outlet of the flare liquid separation tank (1), the low temperature side inlet is connected to the seawater system pipeline, the low temperature side outlet is connected to the sea discharge pipeline, and the high temperature side outlet is connected to the inlet of the liquid ring compressor (42); The high temperature side inlet of the second seawater cooler (41) is connected to the liquid phase outlet of the separator (43), the high temperature side outlet is connected to the high temperature side outlet of the first seawater cooler (40), the low temperature side inlet is connected to the seawater system pipeline, and the low temperature side outlet is connected to the sea discharge pipeline; The outlet of the liquid ring compressor (42) is connected to the inlet of the separator (43); The gas phase outlet of the separator (43) is connected to the fuel gas system.

2. The flare gas recovery and reuse system according to claim 1, characterized in that: The gas recovery module (4) further comprises a first regulating valve (44) arranged at a low-temperature side outlet of the first seawater cooler (40) and a first temperature transmitter (45) arranged at a high-temperature side outlet of the first seawater cooler (40), and the first temperature transmitter (45) can control the opening degree of the first regulating valve (44).

3. The flare gas recovery and reuse system according to claim 1, characterized in that: The gas phase outlet of the separator (43) is also connected to the high temperature side inlet of the first seawater cooler (40) via a first bypass line (5).

4. The flare gas recovery and reuse system according to claim 3, characterized in that: The gas recovery module (4) further comprises a second regulating valve (46) disposed on the first bypass pipeline (5) and a first pressure transmitter (47) disposed at the inlet of the liquid ring compressor (42), and the first pressure transmitter (47) is capable of adjusting the opening of the second regulating valve (46).

5. The flare gas recovery and reuse system according to claim 1, characterized in that: The gas recovery module (4) further comprises a third regulating valve (48) arranged at the liquid phase outlet of the separator (43) and a first liquid level controller (49) arranged on the separator (43), and the first liquid level controller (49) can adjust the opening of the third regulating valve (48).

6. The flare gas recovery and reuse system according to claim 1, characterized in that: The gas recovery module (4) further comprises a fourth regulating valve (410) arranged at the low-temperature side outlet of the second seawater cooler (41) and a second temperature transmitter (411) arranged at the high-temperature side outlet of the second seawater cooler (41), and the second temperature transmitter (411) can control the opening degree of the fourth regulating valve (410).

7. The flare gas recovery and reuse system according to claim 1, characterized in that: The liquid recovery module (2) comprises a filter (21) connected to the flare liquid separation tank (1) and a canned discharge pump (22) connected to the filter (21).

8. The flare gas recovery and reuse system according to claim 7, characterized in that: The liquid recovery module (2) further comprises a second liquid level transmitter (23) arranged on the flare liquid separation tank (1), and the second liquid level transmitter (23) can control the start and stop of the canned discharge pump (22).

9. The flare gas recovery and reuse system according to claim 1, characterized in that: The safety pressure regulating module (3) comprises a pressure regulating valve (31), a fast switching valve (32), a bursting disc (33) and a second bypass pipeline (34) with a valve which are arranged in parallel.

10. The flare gas recovery and reuse system according to claim 9, characterized in that: It also includes a second pressure transmitter (6) arranged on the flare liquid separation tank (1), and the second pressure transmitter (6) can control the start and stop of the liquid ring compressor (42).

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