Control method based on variable flow direction cold-carrying circulation oil gas recovery system

Abstract

The invention discloses a control method based on a variable-flow-direction cold-carrying circulation oil gas recovery system, which comprises the following steps: when a display operation module sets startup, presetting states of a valve and a pump through a central control module, and acquiring actual pressure and temperature; the state of the oil gas and secondary refrigerant valve is adjusted according to comparison between the pressure difference and a set value; temperature control is achieved through a secondary refrigerant pump variable-speed regulator, the pump speed is kept unchanged within the set precision range, and if the pump speed exceeds the set precision range, the rotating speed is correspondingly increased or decreased to adjust the secondary refrigerant flow. According to the invention, the innovative flow-direction-variable cold-carrying circulation cold energy recovery control method is adopted, the configuration of a first-stage refrigeration compressor is reduced, the energy utilization rate of the oil gas recovery unit is greatly improved, and the innovative oil gas flow-direction-variable control method effectively ensures the normal and stable operation of the flow-direction-variable cold-carrying circulation cold energy recovery system.

Description

Technical Field

[0001] The invention relates to the technical field of oil and gas condensation and liquefaction, and in particular to a control method for an oil and gas recovery system based on a variable flow direction cooling cycle. Background Art

[0002] At present, there are common oil and gas recovery systems that can be used for multi-stage deep cooling, with the lowest temperature reaching about -70°C. They are used to condense and liquefy volatile organic compounds in oil and gas (VOCs gas) to recover them. While reducing environmental pollution, the recovered volatile organic compounds can also generate considerable economic benefits.

[0003] However, this type of ordinary oil and gas recovery system will cool the imported oil and gas to -70℃ after multi-stage cooling. The -70℃ oil and gas exhaust gas after cooling and recovery is generally discharged directly into the atmosphere, or heated to about 10℃ by an additional heating device before being discharged into the atmosphere. However, the -70℃ oil and gas exhaust gas at the outlet of the final variable flow cold circulation oil and gas recovery system has a large amount of high-grade refrigeration capacity, which is discharged into the atmosphere in vain or requires energy to be consumed for heating the low-temperature oil and gas before being discharged. This method makes the traditional oil and gas recovery system have many problems such as high energy consumption, high pollution, complex refrigeration system, high cost, low reliability, etc., which seriously restricts the development of oil and gas condensation equipment.

[0004] Therefore, the prior art still needs to be improved and enhanced. Summary of the invention

[0005] In view of the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide a control method for an oil and gas recovery system based on a variable flow refrigeration circulation system, aiming to solve the problems of high energy consumption, high pollution, complex refrigeration system, high cost and low reliability in the control method of the traditional oil and gas recovery system.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A control method based on a variable flow direction refrigeration circulation oil and gas recovery system, wherein the variable flow direction refrigeration circulation oil and gas recovery system comprises: an electrical control subsystem, a variable flow direction oil and gas cooling liquefaction recovery subsystem and a refrigeration circulation heat recovery subsystem; the electrical control subsystem comprises an electrical control box (11), a sensor data acquisition module (113) arranged in the electrical control box (11) and electrically connected in sequence, a display operation module (114) and a central control module (115); a first pressure sensor (13), a first temperature sensor (14), a second pressure sensor (15), a second temperature sensor (16), a third pressure sensor (115) and a third temperature sensor (16) electrically connected to the sensor data acquisition module (113) respectively. 7), a third temperature sensor (18), a fourth pressure sensor (19), a fourth temperature sensor (110), a fifth pressure sensor (111) and a fifth temperature sensor (112); a coolant pump speed regulator (12) electrically connected to the central control module (115); the variable flow direction oil and gas cooling liquefaction recovery subsystem includes a primary cooling module, a secondary cooling module, a third cooling module, and a fourth heating module which are sequentially connected through an oil and gas connecting pipe; wherein the primary cooling module includes: an oil and gas inlet (21), a first oil and gas valve (22), a second oil and gas valve (23), a primary cooling box (24), a third oil and gas valve (25), a fourth oil and gas valve (26) and a first oil and gas connecting pipe. The pipe (27); the oil and gas inlet (21) is divided into two paths, one path is connected to one end of the first oil and gas valve (22), and the other path is connected to one end of the second oil and gas valve (23); the other end of the first oil and gas valve (22) is connected to the inlet of the first cooling box (24), and the other end of the second oil and gas valve (23) is connected to the outlet of the first cooling box (24); the inlet of the first cooling box (24) is also connected to one end of the fourth oil and gas valve (26), and the outlet of the first cooling box (24) is also connected to one end of the third oil and gas valve (25), and the other end of the third oil and gas valve (25) is connected to the other end of the fourth oil and gas valve (26), and is connected to one end of the first oil and gas connecting pipe (27); the cooling cycle heat recovery subsystem includes: a first An oil-gas condenser A (31) and a first-stage oil-gas condenser B (32), a first refrigerant valve (33), a second refrigerant valve (34), a refrigerant pump (35), a fourth-stage oil-gas heater (36), a third refrigerant valve (37), and a fourth refrigerant valve (38); the first-stage oil-gas condenser A (31) and the first-stage oil-gas condenser B (32) are placed side by side and are both installed in the first-stage cooling box (24), and the first-stage oil-gas condenser (A) is adjacent to the inlet of the first-stage cooling box (24), and the first-stage oil-gas condenser B (32) is adjacent to the outlet of the first-stage cooling box (24); the refrigerant outlet of the first-stage oil-gas condenser A (31) is connected to one end of the first refrigerant valve (33);The refrigerant outlet of the first-stage oil-gas condenser B (32) is connected to one end of the second refrigerant valve (34); the other end of the first refrigerant valve (33) is connected to the other end of the second refrigerant valve (34), and then connected to one end of a refrigerant pump (35); the other end of the refrigerant pump (35) is connected to the refrigerant inlet of the fourth-stage oil-gas heater (36); the refrigerant outlet of the fourth-stage oil-gas heater (36) is divided into two paths, one of which is connected to one end of the third refrigerant valve (37). The other end of the third refrigerant valve (37) is connected to the refrigerant inlet of the first-stage oil-gas condenser A (31), and the other end of the fourth refrigerant valve (38) is connected to the refrigerant inlet of the first-stage oil-gas condenser B (32); the first oil-gas valve (22), the second oil-gas valve (23), the third oil-gas valve (25), the fourth oil-gas valve (26), the first refrigerant valve (33), the second refrigerant valve (34), the first refrigerant valve (35), the second refrigerant valve (36), the first refrigerant valve (37), the second refrigerant valve (38), the first refrigerant valve (33), the second refrigerant valve (31), the first refrigerant valve (32), the first refrigerant valve (33), the second refrigerant valve (31), the first refrigerant valve (31 ... The refrigerant valve (34), the third refrigerant valve (37), and the fourth refrigerant valve (38) are all electrically connected to the central control module; the first pressure sensor (13) and the first temperature sensor (14) are arranged at the oil and gas inlet (21); the second pressure sensor (15) and the second temperature sensor (16) are arranged on the first oil and gas connecting pipe connecting the first cooling module and the second cooling module; the third pressure sensor (17) and the third temperature sensor (18) are arranged on the second oil and gas connecting pipe connecting the second cooling module and the third cooling module; the fourth pressure sensor (19) and the fourth temperature sensor (110) are arranged on the third oil and gas connecting pipe connecting the third cooling module and the fourth heating module; the fifth pressure sensor (111) and the fifth temperature sensor (112) are arranged at the oil and gas outlet; the refrigerant pump (35) is electrically connected to the refrigerant pump speed regulator (12);

[0008] The control method comprises:

[0009] When the display operation module is set to start up, the central control module (115) controls the first oil and gas valve (22) to open, the second oil and gas valve (23) to close, the third oil and gas valve (25) to open, the fourth oil and gas valve (26) to close, the first coolant valve (33) to close, the second coolant valve (34) to open, the third coolant valve (37) to close, the fourth coolant valve (38) to open, and the coolant pump (35) to start;

[0010] The actual test pressure of the first pressure sensor (13) is obtained as P1, the actual test pressure of the second pressure sensor (15) is obtained as P2, and the actual test temperature of the second temperature sensor (16) is obtained as T2; the pressure difference P is set on the display operation module (114); 1设定压差 , set the outlet temperature to T 2设定温度 , set the control temperature accuracy to T2设定精度 ;

[0011] When the set pressure difference P1-P2≤P1, the first oil and gas valve (22), the second oil and gas valve (23), the third oil and gas valve (25), the fourth oil and gas valve (26), the first refrigerant valve (33), the second refrigerant valve (34), the third refrigerant valve (37), and the fourth refrigerant valve (38) are controlled to operate according to the original startup setting state;

[0012] When P1-P2>P 1设定压差 When the first oil and gas valve (22) is closed, the second oil and gas valve (23) is opened, the third oil and gas valve (25) is closed, the fourth oil and gas valve (26) is opened, the first coolant valve (33) is opened, the second coolant valve (34) is closed, the third coolant valve (37) is opened, and the fourth coolant valve (38) is closed;

[0013] When T 2设定温度 -T 2设定精度 ≤T2≤T 2设定温度 +T 2设定精度 When the speed of the coolant pump (35) is kept constant by controlling the coolant pump speed regulator (12);

[0014] When T2>T 2设定温度 +T 2设定精度 When the load is 100%, the speed of the brine pump (35) is increased by controlling the brine pump speed regulator (12), thereby increasing the brine flow rate until the load is 100%;

[0015] When T2<T 2设定温度 -T 2设定精度 When the coolant pump (35) is turned off, the coolant pump speed regulator (12) is used to control the coolant pump (35) to reduce the speed and flow rate of the coolant until the machine stops;

[0016] When the display operation module (114) is set to shut down, the first oil and gas valve (22), the second oil and gas valve (23), the third oil and gas valve (25), the fourth oil and gas valve (26), the first coolant valve (33), the second coolant valve (34), the third coolant valve (37), the fourth coolant valve (38), and the coolant pump (35) are all controlled to be closed through the central control module (115).

[0017] The control method of the variable flow direction refrigeration cycle oil and gas recovery system, wherein the secondary cooling module comprises a secondary oil and gas condenser A (28), a secondary oil and gas condenser B (29), a fifth oil and gas valve (210), a sixth oil and gas valve (211), and a second oil and gas connecting pipe (212); the other end of the first oil and gas connecting pipe (27) is divided into two paths, one path is connected to one end of the secondary oil and gas condenser A (28), and the other path is connected to one end of the secondary oil and gas condenser B (29); the other end of the secondary oil and gas condenser A (28) is connected to one end of the fifth oil and gas valve (210), the other end of the secondary oil and gas condenser B (29) is connected to one end of the sixth oil and gas valve (211), the other end of the fifth oil and gas valve (210) is connected to the other end of the sixth oil and gas valve (211), and is connected to one end of the second oil and gas connecting pipe (212); the control method also includes the steps of:

[0018] When the display operation module (114) is set to start up, the fifth oil and gas valve (210) is controlled to be opened and the sixth oil and gas valve (211) is controlled to be closed through the central control module (115);

[0019] The actual test pressure of the third pressure sensor (17) is obtained as P3, the actual test pressure of the second pressure sensor (15) is obtained as P2, and P is set on the display operation module (114). 2设定压差 ;

[0020] When P2-P3≤P 2设定压差 When the fifth oil and gas valve (210) and the sixth oil and gas valve (211) are controlled to operate according to the original startup setting state;

[0021] When P2-P3>P 2设定压差 When the fifth oil and gas valve (210) is controlled to be closed, the sixth oil and gas valve (211) is controlled to be opened;

[0022] When the display operation module (114) is set to shut down, the fifth oil and gas valve (210) and the sixth oil and gas valve (211) are controlled to be completely closed.

[0023] The control method of the variable flow direction refrigeration cycle oil and gas recovery system, wherein the three-stage cooling module comprises a three-stage oil and gas condenser A (213), a three-stage oil and gas condenser B (214), a seventh oil and gas valve (215), an eighth oil and gas valve (216), and a third oil and gas connecting pipe (217); the other end of the second oil and gas connecting pipe (212) is divided into two paths, one path is connected to one end of the three-stage oil and gas condenser A (213), and the other path is connected to one end of the three-stage oil and gas condenser B (214); the other end of the three-stage oil and gas condenser A (213) is connected to one end of the seventh oil and gas valve (215), the other end of the three-stage oil and gas condenser B (214) is connected to one end of the eighth oil and gas valve (216), the other end of the seventh oil and gas valve (215) is connected to the other end of the eighth oil and gas valve (216), and is connected to one end of the third oil and gas connecting pipe (217); the control method also includes the steps of:

[0024] When the display operation module (114) is set to start up, the central control module (115) controls the seventh oil and gas valve (215) to open and the eighth oil and gas valve (216) to close.

[0025] The actual test pressure of the third pressure sensor (17) is obtained as P3, the actual test pressure of the fourth pressure sensor (19) is obtained as P4, and the pressure difference P is set on the display operation module (114). 3设定压差 ;

[0026] When P3-P4≤P 3设定压差 When the seventh oil and gas valve (215) and the eighth oil and gas valve (216) are controlled to operate according to the original startup setting state;

[0027] When P3-P4>P 3设定压差 When the seventh oil and gas valve (215) is controlled to be closed, the eighth oil and gas valve (216) is controlled to be opened;

[0028] When the display operation module (114) is set to shut down, the seventh oil and gas valve (215) is controlled, and the seventh oil and gas valve (215) is completely closed.

[0029] The control method based on the variable flow direction refrigeration cycle oil and gas recovery system, wherein the first-stage oil and gas condenser A and the first-stage oil and gas condenser B are correspondingly connected to a refrigerant pump for cooling, the second-stage oil and gas condenser A and the second-stage oil and gas condenser B are correspondingly connected to a second-stage refrigeration compressor for cooling, and the third-stage oil and gas condenser A and the third-stage oil and gas condenser B are correspondingly connected to a third-stage refrigeration compressor for cooling; the control method also includes the steps of:

[0030] When the display operation module (114) is set to start, the refrigerant pump (35) and the secondary refrigeration compressor are started synchronously;

[0031] The actual test temperature of the third temperature sensor (18) is obtained as T3, and a preset temperature T is set on the display operation module (114). 3预设温度 .

[0032] When T3>T 3预设温度 When , the three-stage refrigeration compressor is controlled to start;

[0033] When T3≤T 3预设温度 When , the three-stage refrigeration compressor is controlled not to start;

[0034] When the display operation module (114) is set to shut down, the third-stage refrigeration compressor is first controlled to shut down, then the second-stage refrigeration compressor is controlled to shut down, and finally the refrigerant pump is controlled to shut down.

[0035] The control method based on the variable flow direction cooling circulation oil and gas recovery system further includes the steps of:

[0036] The actual test temperature of the third temperature sensor (18) is obtained as T3, and the air outlet temperature is set as T on the display operation module (114). 3设定温度 , set the control accuracy to T 3设定精度 ;

[0037] When T 3设定温度 -T 3设定精度 ≤T3≤T 3设定温度 +T 3设定精度 When the load of the secondary refrigeration compressor is controlled to remain unchanged;

[0038] When T3>T 3设定温度 +T 3设定精度 When the secondary refrigeration compressor is loaded,

[0039] When T3<T 3设定温度 -T 3设定精度 When the secondary refrigeration compressor is controlled to unload.

[0040] The control method of the passenger flow phase-changing cooling cycle oil and gas recovery system further includes the following steps:

[0041] The actual test temperature of the fourth temperature sensor (110) is obtained as T4, and the outlet air temperature is set as T on the display operation module (114). 4设定温度 , set the control accuracy to T 4设定精度 ;

[0042] When T 4设定温度 -T 4设定精度 ≤T4≤T 4设定温度 +T 4设定精度 When the load of the three-stage refrigeration compressor is controlled to remain unchanged;

[0043] When T4>T 4设定温度 +T4设定精度 When the load of the three-stage refrigeration compressor is controlled;

[0044] When T4<T 4设定温度 -T 4设定精度 When the 3rd stage refrigeration compressor is controlled to unload.

[0045] Beneficial effects:

[0046] The present invention provides a control method for a variable flow direction refrigeration cycle oil and gas recovery system. The central control module sets input requirements according to the start and stop of the display operation module (114), the inlet and outlet temperatures of each level of oil and gas, and the inlet and outlet pressure difference. The sensor data acquisition system collects data in actual operation, automatically calculates and controls each execution system, and controls the operation of the refrigeration system corresponding to each oil and gas valve, the refrigerant valve, the refrigerant pump, and the oil and gas condensers at each level. The control method of the refrigeration cycle heat recovery oil and gas recovery system of the present invention can effectively recover the cold of oil and gas tail gas at about -70°C, and is used to replace the original compressor refrigeration to provide refrigeration for the first-level oil and gas condenser, reduce the compressor configuration of the first-level oil and gas condenser, and greatly improve the energy utilization rate of the oil and gas recovery unit. The control method of the variable flow direction refrigeration cycle oil and gas recovery system provided by the present invention has the advantages of low energy consumption, energy saving and environmental protection, simple refrigeration system, low cost, high reliability, etc., and greatly improves the energy saving and environmental protection, cost performance and operation reliability of the oil and gas recovery system. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 This is a structural diagram of the variable flow direction cooling circulation oil and gas recovery system provided by the present invention.

[0048] Figure 2 This is a structural diagram of the electrical control subsystem provided by the present invention.

[0049] Figure 3 A flow chart of a control method for a variable flow direction cooling circulation oil and gas recovery system provided by the present invention.

[0050] Main component symbol description: 11-electrical control box, 12-coolant pump speed regulator, 13-first pressure sensor, 14-first temperature sensor, 15-second pressure sensor, 16-second temperature sensor, 17-third pressure sensor, 18-third temperature sensor, 19-fourth pressure sensor, 110-fourth temperature sensor, 111-fifth pressure sensor, 112-fifth temperature sensor, 113-sensor data acquisition module, 114-display operation module, 115-central control module, 21-oil and gas inlet, 22-first oil and gas valve, 23-second oil and gas valve, 24-first cooling box, 25-third oil and gas valve, 26-fourth oil and gas valve, 27-first 1-oil and gas connecting pipe, 28-secondary oil and gas condenser A, 29-secondary oil and gas condenser B, 210-fifth oil and gas valve, 211-sixth oil and gas valve, 212-second oil and gas connecting pipe, 213-third-stage oil and gas condenser A, 214-third-stage oil and gas condenser B, 215-seventh oil and gas valve, 216-eighth oil and gas valve, 217-third oil and gas connecting pipe, 218-fourth-stage heating box, 219-oil and gas outlet, 220-liquid oil outlet pipe, 31-first-stage oil and gas condenser A, 32-first-stage oil and gas condenser B, 33-first refrigerant valve, 34-second refrigerant valve, 35-refrigerant pump, 36-fourth-stage oil and gas heater, 37-third refrigerant valve, 38-fourth refrigerant valve. DETAILED DESCRIPTION

[0051] The present invention provides a control method for a variable flow direction refrigeration cycle oil and gas recovery system. In order to make the purpose, technical solution and effect of the present invention clearer and more specific, the present invention is further described in detail below with reference to the accompanying drawings and examples.

[0052] In the description of the present invention, it should be understood that the orientation or position relationship indicated by the terms "top", "bottom", etc. is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present invention and simplifying the description, and cannot be understood as a limitation on the present invention; in addition, the terms "installation", "connection", etc. should be understood in a broad sense, and for ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0053] See also Figures 1 to 3The present invention provides a control method based on a variable flow direction cooling circulation oil and gas recovery system, wherein the variable flow direction cooling circulation oil and gas recovery system comprises: an electrical control subsystem, a variable flow direction oil and gas cooling liquefaction recovery subsystem and a cooling circulation heat recovery subsystem; the electrical control subsystem comprises an electrical control box (11), a sensor data acquisition module (113) arranged in the electrical control box (11) and electrically connected in sequence, a display operation module (114) and a central control module (115); a first pressure sensor (13), a first temperature sensor (14), a second pressure sensor (15), a second temperature sensor (16), a third pressure sensor (17) and a second pressure sensor (18) which are electrically connected to the sensor data acquisition module (113) respectively. a coolant pump speed regulator (12) electrically connected to the central control module (115); the variable flow direction oil and gas cooling liquefaction recovery subsystem comprises a primary cooling module, a secondary cooling module, a third cooling module, and a fourth heating module which are sequentially connected through an oil and gas connecting pipe; wherein the primary cooling module comprises: an oil and gas inlet (21), a first oil and gas valve (22), a second oil and gas valve (23), a primary cooling box (24), a third oil and gas valve (25), a fourth oil and gas valve (26) and a first oil and gas inlet (21); a third oil and gas valve (22), a fourth oil and gas valve (23), a primary cooling box (24), a third oil and gas valve (25), a fourth oil and gas valve (26) and a first oil and gas inlet (21); a third oil and gas valve (25), a fourth oil and gas valve (26) and a fifth temperature sensor (112); a coolant pump speed regulator (12) electrically connected to the central control module (115); the variable flow direction oil and gas cooling liquefaction recovery subsystem comprises a primary cooling module, a secondary cooling module, a third cooling module, and a fourth heating module which are sequentially connected through an oil and gas connecting pipe; wherein the primary cooling module comprises: an oil and gas inlet (21), a first oil and gas valve (22), a second oil and gas valve (23), a primary cooling box (24), a third oil and gas valve (25), a fourth oil and gas valve (26) and a first oil and gas inlet (21); ... fourth oil and gas inlet (21); a third oil and gas valve (25), a fifth temperature sensor (111) and a fifth temperature sensor (112); The gas connecting pipe (27); the gas inlet (21) is divided into two paths, one path is connected to one end of the first gas valve (22), and the other path is connected to one end of the second gas valve (23); the other end of the first gas valve (22) is connected to the inlet of the first cooling box (24), and the other end of the second gas valve (23) is connected to the outlet of the first cooling box (24); the inlet of the first cooling box (24) is also connected to one end of the fourth gas valve (26), and the outlet of the first cooling box (24) is also connected to one end of the third gas valve (25), and the other end of the third gas valve (25) is connected to the other end of the fourth gas valve (26) and connected to one end of the first gas connecting pipe (27); the cooling cycle heat recovery subsystem comprises: a first-stage oil-gas condenser A (31) and a first-stage oil-gas condenser B (32), a first refrigerant valve (33), a second refrigerant valve (34), a refrigerant pump (35), a fourth-stage oil-gas heater (36), a third refrigerant valve (37), and a fourth refrigerant valve (38); the first-stage oil-gas condenser A (31) and the first-stage oil-gas condenser B (32) are placed side by side and are both installed in the first-stage cooling box (24), and the first-stage oil-gas condenser (A) is adjacent to the inlet of the first-stage cooling box (24), and the first-stage oil-gas condenser B (32) is adjacent to the outlet of the first-stage cooling box (24); the refrigerant outlet of the first-stage oil-gas condenser A (31) is connected to one end of the first refrigerant valve (33);The refrigerant outlet of the first-stage oil-gas condenser B (32) is connected to one end of the second refrigerant valve (34); the other end of the first refrigerant valve (33) is connected to the other end of the second refrigerant valve (34), and then connected to one end of a refrigerant pump (35); the other end of the refrigerant pump (35) is connected to the refrigerant inlet of the fourth-stage oil-gas heater (36); the refrigerant outlet of the fourth-stage oil-gas heater (36) is divided into two paths, one of which is connected to one end of the third refrigerant valve (37), and the other is connected to the refrigerant inlet of the fourth-stage oil-gas heater (36). One end is connected to one end of the fourth refrigerant valve (38), the other end of the third refrigerant valve (37) is connected to the refrigerant inlet of the first-stage oil-gas condenser A (31), and the other end of the fourth refrigerant valve (38) is connected to the refrigerant inlet of the first-stage oil-gas condenser B (32); the first oil-gas valve (22), the second oil-gas valve (23), the third oil-gas valve (25), the fourth oil-gas valve (26), the first refrigerant valve (33), the second refrigerant valve ( 34), a third coolant valve (37), and a fourth coolant valve (38) are all electrically connected to the central control module; the first pressure sensor (13) and the first temperature sensor (14) are arranged at the oil and gas inlet (21), the second pressure sensor (15) and the second temperature sensor (16) are arranged on the first oil and gas connecting pipe connecting the first cooling module and the second cooling module, the third pressure sensor (17) and the third temperature sensor (18) are arranged on the second oil and gas connecting pipe connecting the second cooling module and the third cooling module, the fourth pressure sensor (19) and the fourth temperature sensor (110) are arranged on the third oil and gas connecting pipe connecting the third cooling module and the fourth heating module, and the fifth pressure sensor (111) and the fifth temperature sensor (112) are arranged at the oil and gas outlet; the coolant pump (35) is electrically connected to the coolant pump speed regulator (12); the control method comprises:

[0054] S100, when the display operation module is set to start, the central control module (115) controls the first oil and gas valve (22) to open, the second oil and gas valve (23) to close, the third oil and gas valve (25) to open, the fourth oil and gas valve (26) to close, the first coolant valve (33) to close, the second coolant valve (34) to open, the third coolant valve (37) to close, the fourth coolant valve (38) to open, and the coolant pump (35) to start;

[0055] S200, obtaining the actual test pressure of the first pressure sensor (13) as P1, the actual test pressure of the second pressure sensor (15) as P2, and the actual test temperature of the second temperature sensor (16) as T2; setting the pressure difference P on the display operation module (114); 1设定压差 , set the outlet temperature to T 2设定温度 , set the control temperature accuracy to T 2设定精度 ;

[0056] S300, when P1-P2≤P 1设定压差 When the first oil and gas valve (22), the second oil and gas valve (23), the third oil and gas valve (25), the fourth oil and gas valve (26), the first refrigerant valve (33), the second refrigerant valve (34), the third refrigerant valve (37), and the fourth refrigerant valve (38) are controlled to operate according to the original startup setting state;

[0057] S400, when P1-P2>P 1设定压差 When the first oil and gas valve (22) is closed, the second oil and gas valve (23) is opened, the third oil and gas valve (25) is closed, the fourth oil and gas valve (26) is opened, the first coolant valve (33) is opened, the second coolant valve (34) is closed, the third coolant valve (37) is opened, and the fourth coolant valve (38) is closed;

[0058] S500, when T 2设定温度 -T 2设定精度 ≤T2≤T 2设定温度 +T 2设定精度 When the speed of the coolant pump (35) is kept constant by controlling the coolant pump speed regulator (12);

[0059] S600, when T2>T 2设定温度 +T 2设定精度 When the load is 100%, the speed of the brine pump (35) is increased by controlling the brine pump speed regulator (12), thereby increasing the brine flow rate until the load is 100%;

[0060] S700, when T2<T 2设定温度 -T 2设定精度 When the coolant pump (35) is turned off, the coolant pump speed regulator (12) is used to control the coolant pump (35) to reduce the speed and flow rate of the coolant until the machine stops;

[0061] S800, when the display operation module (114) is set to shut down, the first oil and gas valve (22), the second oil and gas valve (23), the third oil and gas valve (25), the fourth oil and gas valve (26), the first coolant valve (33), the second coolant valve (34), the third coolant valve (37), the fourth coolant valve (38), and the coolant pump (35) are all controlled to be closed through the central control module (115).

[0062] For general oil and gas recovery systems, the -70℃ exhaust gas of the imported oil and gas is cooled at multiple stages and then discharged into the atmosphere in vain or even requires energy to be used to heat the low-temperature oil and gas before being discharged. The high-quality refrigeration capacity of the -70℃ exhaust gas is not effectively recovered and utilized, resulting in the traditional oil and gas recovery method having many problems such as high energy consumption, high pollution, complex refrigeration system, high cost and low reliability.

[0063] In order to solve the problems of the above-mentioned general oil and gas recovery system, the present invention adopts an innovative control method based on a variable flow direction refrigeration cycle oil and gas recovery system, and adopts the higher temperature refrigerant coming out of the first-level oil and gas condenser in the refrigeration cycle heat recovery subsystem, and absorbs the cold of the oil and gas exhaust gas at about -70°C through the four-stage oil and gas heater, and cools it down to become a lower temperature refrigerant, and at the same time heats the -70°C oil and gas exhaust gas to about 10°C for discharge; the lower temperature refrigerant enters the first-level oil and gas condenser, dissipates the cold to reduce the temperature of the inlet oil and gas, absorbs the heat of the inlet oil and gas to heat it up to become a higher temperature refrigerant, and the cycle runs in this way.

[0064] The present invention controls the opening and closing of corresponding oil and gas valves and refrigerant valves and adjusts the flow rate of the refrigerant pump based on the comparison between the actual pressure difference and the set pressure difference and the comparison between the actual temperature and the set temperature, thereby realizing the effective recovery of the cooling capacity of the oil and gas exhaust gas at about -70°C through the refrigerant, which is used to replace the original compressor refrigeration to provide cooling capacity for the first-stage oil and gas condenser, reduce the compressor configuration of the first-stage oil and gas cooler, and greatly improve the energy utilization rate of the oil and gas recovery unit.

[0065] Specifically, when the display operation module is set to be turned on, the first oil and gas valve (22) is opened, the second oil and gas valve (23) is closed, the third oil and gas valve (25) is opened, the fourth oil and gas valve (26) is closed, the first coolant valve (33) is closed, the second coolant valve (34) is opened, the third coolant valve (37) is closed, the fourth coolant valve (38) is opened, and the coolant pump (35) is turned on. At this time, the high-temperature and high-pressure oil and gas first enters the first-stage oil and gas condenser A (31) from the oil and gas inlet (21), and then enters the first-stage oil and gas condenser B (32) for cooling. At this time, since the first coolant valve (33) and the third coolant valve (37) are in a closed state, the second coolant valve (34) and the fourth coolant valve (38) are in an open state, the coolant does not pass through the first-stage oil and gas condenser A, but only passes through the first-stage oil and gas condenser B. In this process, the first-stage oil and gas condenser B gradually cools down after the coolant absorbs heat. At this time, the actual pressure difference between the first pressure sensor and the second pressure sensor is obtained in real time, and the actual pressure difference is compared with the preset pressure difference. If it is monitored that P1-P2≤P 1设定压差 , it means that the actual pressure difference between the first pressure sensor and the second pressure sensor is not large, and it is determined that the first-stage oil and gas condenser B (32) is not frosted temporarily. At this time, the first oil and gas valve (22), the second oil and gas valve (23), the third oil and gas valve (25), the fourth oil and gas valve (26), the first refrigerant valve (33), the second refrigerant valve (34), the third refrigerant valve (37), and the fourth refrigerant valve (38) are controlled to continue to operate according to the original startup state;

[0066] When P1-P2>P1设定压差 When the pressure difference between the first pressure sensor and the second pressure sensor is large, it means that the actual pressure difference between the first pressure sensor and the second pressure sensor is large, that is, the wind resistance in the first-stage oil and gas condenser B is large. At this time, it is determined that the first-stage oil and gas condenser B (32) is frosted, and the central control module (115) controls the first oil and gas valve (22) to be closed, the second oil and gas valve (23) to be opened, the third oil and gas valve (25) to be closed, the fourth oil and gas valve (26) to be opened, the first refrigerant valve (33) to be opened, the second refrigerant valve (34) to be closed, the third refrigerant valve (37) to be opened, and the fourth refrigerant valve (38) to be closed. At this time, the high-temperature and high-pressure oil and gas have switched the flow through the oil and gas valves. In terms of flow direction, the high-temperature and high-pressure oil and gas are first defrosted through the frosted first-level oil and gas condenser B, and then enter the first-level oil and gas condenser A for cooling. In this process, the refrigerant does not pass through the first-level oil and gas condenser B, but only passes through the first-level oil and gas condenser A. In this process, the high-temperature and high-pressure oil and gas are first defrosted through the frosted first-level oil and gas condenser B, and then enter the first-level oil and gas condenser A for further cooling. In this way, by cyclically switching the oil and gas flow direction and the refrigerant flow direction, the cooling, frosting and defrosting cycles can be cleverly achieved, thereby effectively ensuring the normal and stable operation of the variable flow direction cold-carrying circulation oil and gas recovery system.

[0067] In the above process, the refrigerant absorbs the heat of high-temperature and high-pressure oil and gas and becomes a higher-temperature refrigerant. At this time, the higher-temperature refrigerant absorbs the cold of the oil and gas exhaust gas at about -70°C through the four-stage oil and gas heater, and is cooled to become a lower-temperature refrigerant. At the same time, the -70°C oil and gas exhaust gas is heated to about 10°C for discharge.

[0068] In the present invention, when T 2设定温度 -T 2设定精度 ≤T2≤T 2设定温度 +T 2设定精度 When T2>T 2设定温度 +T 2设定精度 When T2<T 2设定温度 -T 2设定精度 When the temperature of the high-temperature and high-pressure oil and gas is too high in the first-stage cooling module, the speed of the coolant pump (35) can be reduced by the coolant pump speed regulator (12), thereby reducing the coolant flow rate until the machine stops.

[0069] The present invention effectively solves the problems of traditional oil and gas recovery systems, such as high energy consumption, high pollution, complex refrigeration system, high cost, and low reliability. Compared with the general oil and gas recovery system, it reduces the configuration of the primary refrigeration compressor through the innovative variable flow cold cycle cold recovery and intelligent control method, greatly improves the energy utilization rate of the oil and gas recovery unit, and effectively ensures the normal and stable operation of the variable flow cold cycle cold recovery system. It has the advantages of low energy consumption, energy saving and environmental protection, simple refrigeration system, low cost, high reliability, etc., and greatly improves the energy saving and environmental protection, cost performance and operation reliability of the oil and gas recovery system.

[0070] In some embodiments, the secondary cooling module includes a secondary oil and gas condenser A (28), a secondary oil and gas condenser B (29), a fifth oil and gas valve (210), a sixth oil and gas valve (211), and a second oil and gas connecting pipe (212); the other end of the first oil and gas connecting pipe (27) is divided into two paths, one path is connected to one end of the secondary oil and gas condenser A (28), and the other path is connected to one end of the secondary oil and gas condenser B (29); the other end of the secondary oil and gas condenser A (28) is connected to one end of the fifth oil and gas valve (210), and the other end of the secondary oil and gas condenser B (29) is connected to the sixth oil and gas valve (211). The control method further comprises the steps of: when the display operation module (114) is set to be turned on, controlling the fifth oil and gas valve (210) to be opened and the sixth oil and gas valve (211) to be closed through the central control module (115); obtaining the actual test pressure of the third pressure sensor (17) as P3 and the actual test pressure of the second pressure sensor (15) as P2, setting P on the display operation module (114); and 2设定压差 ; When P2-P3≤P 2设定压差 When P2-P3>P 2设定压差 When the display operation module (114) is set to shut down, the fifth oil and gas valve (210) and the sixth oil and gas valve (211) are controlled to be closed. When the display operation module (114) is set to shut down, the fifth oil and gas valve (210) and the sixth oil and gas valve (211) are controlled to be closed.

[0071] In this embodiment, when the display operation module (114) is set to be turned on, the fifth oil and gas valve (210) is controlled by the central control module (115) to be opened and the sixth oil and gas valve (211) is closed. At this time, the oil and gas coming out of the first oil and gas connecting pipe (27) is further cooled by the secondary oil and gas condenser A (28). In this process, the actual pressure difference between the second pressure sensor (15) and the third pressure sensor (17) is obtained in real time, and the actual pressure difference is compared with the preset pressure difference. If it is detected that P2-P3≤P 2设定压差 , indicating that the actual pressure difference between the second pressure sensor and the third pressure sensor is not large, and it is determined that the secondary oil-gas condenser A (28) is temporarily not frosted, and the fifth oil-gas valve (210) and the sixth oil-gas valve (211) are controlled to operate according to the original startup setting state; if it is monitored that P2-P3>P 2设定压差 , it means that the actual pressure difference between the second pressure sensor and the third pressure sensor is large, that is, the wind resistance in the secondary oil and gas condenser A (28) is large. At this time, it is determined that the secondary oil and gas condenser A (28) is frosted, and the fifth oil and gas valve (210) is controlled to be closed and the sixth oil and gas valve (211) is opened through the central control module (115). At this time, the oil and gas have switched the flow direction through the oil and gas valve. At this time, the oil and gas are cooled through the secondary oil and gas condenser B (29). In this way, by cyclically switching the oil and gas flow direction, the oil and gas cooling, frosting and defrosting cycle is efficiently realized, thereby effectively ensuring the normal and stable operation of the variable flow direction cold cycle oil and gas recovery system.

[0072] In some embodiments, the three-stage cooling module includes a three-stage oil-gas condenser A (213), a three-stage oil-gas condenser B (214), a seventh oil-gas valve (215), an eighth oil-gas valve (216), and a third oil-gas connecting pipe (217); the other end of the second oil-gas connecting pipe (212) is divided into two paths, one of which is connected to one end of the three-stage oil-gas condenser A (213), and the other is connected to one end of the three-stage oil-gas condenser B (214); the other end of the three-stage oil-gas condenser A (213) is connected to the seventh oil-gas valve (215), and the eighth oil-gas valve (216) is connected to the third oil-gas connecting pipe (217); The third pressure sensor (17) is connected to one end of the gas valve (215), the other end of the third-stage oil and gas condenser B (214) is connected to one end of the eighth oil and gas valve (216), the other end of the seventh oil and gas valve (215) is connected to the other end of the eighth oil and gas valve (216), and is connected to one end of the third oil and gas connecting pipe (217); the control method also includes the steps of: when the display operation module (114) is set to start, the seventh oil and gas valve (215) is controlled to open and the eighth oil and gas valve (216) is closed through the central control module (115). The actual test pressure of the third pressure sensor (17) is obtained as P3, the actual test pressure of the fourth pressure sensor (19) is obtained as P4, and the pressure difference P is set on the display operation module (114). 3设定压差 ; When P3-P4≤P 3设定压差When P3-P4>P 3设定压差 When the display operation module (114) is set to shut down, the seventh oil and gas valve (215) is controlled to close and the eighth oil and gas valve (216) is opened; when the display operation module (114) is set to shut down, the seventh oil and gas valve (215) is controlled to close.

[0073] In this embodiment, when the display operation module (114) is set to be turned on, the seventh oil and gas valve (215) is controlled by the central control module (115) to be opened and the eighth oil and gas valve (216) is closed. At this time, the oil and gas coming out of the second oil and gas connecting pipe (212) is further cooled by the three-stage oil and gas condenser A (213). In this process, the actual pressure difference between the third pressure sensor (17) and the fourth pressure sensor (19) is obtained in real time, and the actual pressure difference is compared with the preset pressure difference. If it is detected that P3-P4≤P 3设定压差 , indicating that the actual pressure difference between the third pressure sensor and the fourth pressure sensor is not large, and it is determined that the third-stage oil-gas condenser A (213) is temporarily not frosted, and the seventh oil-gas valve (215) and the eighth oil-gas valve (216) are controlled to operate according to the original startup setting state; if it is monitored that P3-P4>P 3设定压差 , it means that the actual pressure difference between the third pressure sensor and the fourth pressure sensor is large, that is, the wind resistance in the three-stage oil and gas condenser A (212) is large. At this time, it is determined that the three-stage oil and gas condenser A (212) is frosted, and the seventh oil and gas valve (215) is controlled to be closed and the eighth oil and gas valve (216) is opened through the central control module (115). At this time, the oil and gas have switched the flow direction through the oil and gas valve. At this time, the oil and gas are cooled through the three-stage oil and gas condenser B (214). In this way, by cyclically switching the oil and gas flow direction, the oil and gas cooling, frosting and defrosting cycle is efficiently realized, thereby effectively ensuring the normal and stable operation of the variable flow direction cold cycle oil and gas recovery system.

[0074] In some embodiments, the first-stage oil-gas condenser A and the first-stage oil-gas condenser B are connected to a coolant pump for cooling, the second-stage oil-gas condenser A and the second-stage oil-gas condenser B are connected to a second-stage refrigeration compressor for cooling, and the third-stage oil-gas condenser A and the third-stage oil-gas condenser B are connected to a third-stage refrigeration compressor for cooling; the control method further comprises the steps of: when the display operation module (114) is set to start, synchronously starting the coolant pump (35) and the second-stage refrigeration compressor; obtaining the actual test temperature T3 of the third temperature sensor (18), and setting the preset temperature T3 on the display operation module (114); 3预设温度 When T3>T 3预设温度When T3≤T 3预设温度 When the display operation module (114) is set to shut down, the third-stage refrigeration compressor is first controlled to shut down, then the second-stage refrigeration compressor is controlled to shut down, and finally the refrigerant pump is controlled to shut down.

[0075] In some embodiments, the actual test temperature of the third temperature sensor (18) is obtained as T3, and the air outlet temperature is set as T on the display operation module (114). 3设定温度 , set the control accuracy to T 3设定精度 When T 3设定温度 -T 3设定精度 ≤T3≤T 3设定温度 +T 3设定精度 When T3>T 3设定温度 +T 3设定精度 When T3<T 3设定温度 -T 3设定精度 It means that the high-temperature and high-pressure oil and gas are cooled too fast in the secondary cooling module. At this time, the secondary refrigeration compressor can be controlled to unload.

[0076] In some embodiments, the actual test temperature of the fourth temperature sensor (110) is obtained as T4, and the outlet temperature is set as T on the display operation module (114). 4设定温度 , set the control accuracy to T 4设定精度 When T 4设定温度 -T 4设定精度 ≤T4≤T 4设定温度 +T 4设定精度 When T4>T 4设定温度 +T 4设定精度 When T4<T 4设定温度 -T 4设定精度 It means that the high-temperature and high-pressure oil and gas are cooling too fast in the three-stage cooling module. At this time, the three-stage refrigeration compressor can be controlled to unload.

[0077] In summary, the present invention adopts an innovative control method based on a variable flow direction refrigeration cycle oil and gas recovery system, adopts a higher temperature refrigerant from the first-stage oil and gas condenser in the refrigeration cycle heat recovery subsystem, absorbs the cold of the oil and gas tail gas at about -70°C through the four-stage oil and gas heater, cools down to become a lower temperature refrigerant, and heats the -70°C oil and gas tail gas to about 10°C for discharge; the lower temperature refrigerant enters the first-stage oil and gas condenser, dissipates cold to reduce the temperature of the inlet oil and gas, absorbs the heat of the inlet oil and gas and heats up to become a higher temperature refrigerant, and operates in this cycle. The present invention controls the opening and closing of the corresponding oil and gas valve and the refrigerant valve based on the comparison between the actual pressure difference and the set pressure difference and the comparison between the actual temperature and the set temperature, and adjusts the flow of the refrigerant pump, so as to realize the effective recovery of the cold of the oil and gas tail gas at about -70°C through the refrigerant, which is used to replace the original compressor refrigeration to provide refrigeration for the first-stage oil and gas condenser, reduce the compressor configuration of the first-stage oil and gas cooler, and greatly improve the energy utilization rate of the oil and gas recovery unit.

[0078] It is understandable that those skilled in the art can make equivalent substitutions or changes based on the technical solution and inventive concept of the present invention, and all these changes or substitutions should fall within the protection scope of the present invention.

Claims

1. A control method for a variable flow cooling circulation oil and gas recovery system, characterized in that: The variable flow direction cooling circulation oil and gas recovery system comprises: an electrical control subsystem, a variable flow direction oil and gas cooling liquefaction recovery subsystem and a cooling circulation heat recovery subsystem; the electrical control subsystem comprises an electrical control box (11), a sensor data acquisition module (113) arranged in the electrical control box (11) and electrically connected in sequence, a display operation module (114) and a central control module (115); a first pressure sensor (13), a first temperature sensor (14), a second pressure sensor (15), a second temperature sensor (16), a third pressure sensor (17), a third temperature sensor (18), a fourth pressure sensor (19), a fourth temperature sensor (19) and a fifth pressure sensor (115) electrically connected to the sensor data acquisition module (113) respectively. a temperature sensor (110), a fifth pressure sensor (111) and a fifth temperature sensor (112); a coolant pump speed regulator (12) electrically connected to the central control module (115); the variable flow direction oil and gas cooling liquefaction recovery subsystem comprises a primary cooling module, a secondary cooling module, a third cooling module and a fourth heating module which are sequentially connected through an oil and gas connecting pipe; wherein the primary cooling module comprises: an oil and gas inlet (21), a first oil and gas valve (22), a second oil and gas valve (23), a primary cooling box (24), a third oil and gas valve (25), a fourth oil and gas valve (26) and a first oil and gas connecting pipe (27); the oil and gas inlet (21) is divided into two paths, one of which is connected to the first oil and gas valve ( The first cooling box (24) is connected to one end of the first cooling box (24), and the other end of the first cooling box (24) is connected to one end of the second oil and gas valve (23). The other end of the first oil and gas valve (22) is connected to the inlet of the first cooling box (24), and the other end of the second oil and gas valve (23) is connected to the outlet of the first cooling box (24); the inlet of the first cooling box (24) is also connected to one end of the fourth oil and gas valve (26), and the outlet of the first cooling box (24) is also connected to one end of the third oil and gas valve (25), and the other end of the third oil and gas valve (25) is connected to the other end of the fourth oil and gas valve (26), and is connected to one end of the first oil and gas connecting pipe (27); the cooling circulation heat recovery subsystem includes: a first oil and gas condenser A (31) and a first oil and gas condenser B (32), a first cooling agent valve (3 3), a second coolant valve (34), a coolant pump (35), a fourth-stage oil-gas heater (36), a third coolant valve (37), and a fourth coolant valve (38); the first-stage oil-gas condenser A (31) and the first-stage oil-gas condenser B (32) are placed side by side and are both installed in the first-stage cooling box (24), and the first-stage oil-gas condenser (A) is adjacent to the inlet of the first-stage cooling box (24), and the first-stage oil-gas condenser B (32) is adjacent to the outlet of the first-stage cooling box (24); the coolant outlet of the first-stage oil-gas condenser A (31) is connected to one end of the first coolant valve (33); the coolant outlet of the first-stage oil-gas condenser B (32) is connected to one end of the second coolant valve (34);After the other end of the first coolant valve (33) is connected to the other end of the second coolant valve (34), it is connected to one end of the coolant pump (35), and the other end of the coolant pump (35) is connected to the coolant inlet of the fourth-stage oil and gas heater (36); the coolant outlet of the fourth-stage oil and gas heater (36) is divided into two paths, one of which is connected to one end of the third coolant valve (37), and the other is connected to one end of the fourth coolant valve (38). The other end of the third coolant valve (37) is connected to the coolant inlet of the first-stage oil and gas condenser A (31), and the other end of the fourth coolant valve (38) is connected to the coolant inlet of the first-stage oil and gas condenser B (32); the first oil and gas valve (22), the second oil and gas valve (23), the third oil and gas valve (25), the fourth oil and gas valve (26), the first coolant valve (33), the second coolant valve (34), the third coolant valve (37), and the fourth coolant valve (38) are all electrically connected to the central control module; the first pressure sensor (13) and the first temperature sensor (14) are arranged at the oil and gas inlet (21), the second pressure sensor (15) and the second temperature sensor (16) are arranged on the first oil and gas connecting pipe connecting the first cooling module and the second cooling module, the third pressure sensor (17) and the third temperature sensor (18) are arranged on the second oil and gas connecting pipe connecting the second cooling module and the third cooling module, the fourth pressure sensor (19) and the fourth temperature sensor (110) are arranged on the third oil and gas connecting pipe connecting the third cooling module and the fourth heating module, and the fifth pressure sensor (111) and the fifth temperature sensor (112) are arranged at the oil and gas outlet; the coolant pump (35) is electrically connected to the coolant pump speed regulator (12); The control method comprises: When the display operation module is set to start up, the central control module (115) controls the first oil and gas valve (22) to open, the second oil and gas valve (23) to close, the third oil and gas valve (25) to open, the fourth oil and gas valve (26) to close, the first coolant valve (33) to close, the second coolant valve (34) to open, the third coolant valve (37) to close, the fourth coolant valve (38) to open, and the coolant pump (35) to start; The actual test pressure of the first pressure sensor (13) is obtained as P1, the actual test pressure of the second pressure sensor (15) is obtained as P2, and the actual test temperature of the second temperature sensor (16) is obtained as T2; the pressure difference P is set on the display operation module (114); 1设定压差 , set the outlet temperature to T 2设定温度 , set the control temperature accuracy to T 2设定精度 ; When P1-P2≤P 1设定压差 When the first oil and gas valve (22), the second oil and gas valve (23), the third oil and gas valve (25), the fourth oil and gas valve (26), the first refrigerant valve (33), the second refrigerant valve (34), the third refrigerant valve (37), and the fourth refrigerant valve (38) are controlled to operate according to the original startup setting state; When P1-P2>P 1设定压差 When the first oil and gas valve (22) is closed, the second oil and gas valve (23) is opened, the third oil and gas valve (25) is closed, the fourth oil and gas valve (26) is opened, the first coolant valve (33) is opened, the second coolant valve (34) is closed, the third coolant valve (37) is opened, and the fourth coolant valve (38) is closed; When T 2设定温度 -T 2设定精度 ≤T2≤T 2设定温度 +T 2设定精度 When the speed of the coolant pump (35) is kept constant by controlling the coolant pump speed regulator (12); When T2>T 2设定温度 +T 2设定精度 When the load is 100%, the speed of the brine pump (35) is increased by controlling the brine pump speed regulator (12), thereby increasing the brine flow rate until the load is 100%; When T2<T 2设定温度 -T 2设定精度 When the coolant pump (35) is turned off, the coolant pump speed regulator (12) is used to control the coolant pump (35) to reduce the speed and flow rate of the coolant until the machine stops; When the display operation module (114) is set to shut down, the first oil and gas valve (22), the second oil and gas valve (23), the third oil and gas valve (25), the fourth oil and gas valve (26), the first coolant valve (33), the second coolant valve (34), the third coolant valve (37), the fourth coolant valve (38), and the coolant pump (35) are all controlled to be closed through the central control module (115).

2. The control method of the variable flow direction cooling circulation oil and gas recovery system according to claim 1 is characterized in that: The secondary cooling module comprises a secondary oil and gas condenser A (28), a secondary oil and gas condenser B (29), a fifth oil and gas valve (210), a sixth oil and gas valve (211), and a second oil and gas connecting pipe (212); the other end of the first oil and gas connecting pipe (27) is divided into two paths, one path is connected to one end of the secondary oil and gas condenser A (28), and the other path is connected to one end of the secondary oil and gas condenser B (29); the other end of the secondary oil and gas condenser A (28) is connected to one end of the fifth oil and gas valve (210), the other end of the secondary oil and gas condenser B (29) is connected to one end of the sixth oil and gas valve (211), the other end of the fifth oil and gas valve (210) is connected to the other end of the sixth oil and gas valve (211), and is connected to one end of the second oil and gas connecting pipe (212); the control method further comprises the steps of: When the display operation module (114) is set to start up, the fifth oil and gas valve (210) is controlled to be opened and the sixth oil and gas valve (211) is controlled to be closed through the central control module (115); The actual test pressure of the third pressure sensor (17) is obtained as P3, the actual test pressure of the second pressure sensor (15) is obtained as P2, and P is set on the display operation module (114). 2设定压差 ; When P2-P3≤P 2设定压差 When the fifth oil and gas valve (210) and the sixth oil and gas valve (211) are controlled to operate according to the original startup setting state; When P2-P3>P 2设定压差 When the fifth oil and gas valve (210) is controlled to be closed, the sixth oil and gas valve (211) is controlled to be opened; When the display operation module (114) is set to shut down, the fifth oil and gas valve (210) and the sixth oil and gas valve (211) are controlled to be completely closed.

3. The control method of the variable flow direction cooling circulation oil and gas recovery system according to claim 2 is characterized in that: The three-stage cooling module comprises a three-stage oil-gas condenser A (213), a three-stage oil-gas condenser B (214), a seventh oil-gas valve (215), an eighth oil-gas valve (216), and a third oil-gas connecting pipe (217); the other end of the second oil-gas connecting pipe (212) is divided into two paths, one path is connected to one end of the three-stage oil-gas condenser A (213), and the other path is connected to one end of the three-stage oil-gas condenser B (214); the other end of the three-stage oil-gas condenser A (213) is connected to one end of the seventh oil-gas valve (215), the other end of the three-stage oil-gas condenser B (214) is connected to one end of the eighth oil-gas valve (216), the other end of the seventh oil-gas valve (215) is connected to the other end of the eighth oil-gas valve (216), and is connected to one end of the third oil-gas connecting pipe (217); the control method further comprises the steps of: When the display operation module (114) is set to start up, the central control module (115) controls the seventh oil and gas valve (215) to open and the eighth oil and gas valve (216) to close. The actual test pressure of the third pressure sensor (17) is obtained as P3, the actual test pressure of the fourth pressure sensor (19) is obtained as P4, and the pressure difference P is set on the display operation module (114). 3设定压差 ; When P3-P4≤P 3设定压差 When the seventh oil and gas valve (215) and the eighth oil and gas valve (216) are controlled to operate according to the original startup setting state; When P3-P4>P 3设定压差 When the seventh oil and gas valve (215) is controlled to be closed, the eighth oil and gas valve (216) is controlled to be opened; When the display operation module (114) is set to shut down, the seventh oil and gas valve (215) is controlled, and the seventh oil and gas valve (215) is completely closed.

4. The control method of the variable flow direction cooling circulation oil and gas recovery system according to claim 3 is characterized in that: The first-stage oil-gas condenser A and the first-stage oil-gas condenser B are connected to a refrigerant pump for cooling, the second-stage oil-gas condenser A and the second-stage oil-gas condenser B are connected to a second-stage refrigeration compressor for cooling, and the third-stage oil-gas condenser A and the third-stage oil-gas condenser B are connected to a third-stage refrigeration compressor for cooling; the control method also includes the steps of: When the display operation module (114) is set to start, the refrigerant pump (35) and the secondary refrigeration compressor are started synchronously; The actual test temperature of the third temperature sensor (18) is obtained as T3, and a preset temperature T is set on the display operation module (114). 3预设温度 ; When T3>T 3预设温度 When , the three-stage refrigeration compressor is controlled to start; When T3≤T 3预设温度 When , the three-stage refrigeration compressor is controlled not to start; When the display operation module (114) is set to shut down, the third-stage refrigeration compressor is first controlled to shut down, then the second-stage refrigeration compressor is controlled to shut down, and finally the refrigerant pump is controlled to shut down.

5. The control method of the variable flow direction cooling circulation oil and gas recovery system according to claim 4 is characterized in that: Also includes the steps: The actual test temperature of the third temperature sensor (18) is obtained as T3, and the air outlet temperature is set as T on the display operation module (114). 3设定温度 , set the control accuracy to T 3设定精度 ; When T 3设定温度 -T 3设定精度 ≤T3≤T 3设定温度 +T 3设定精度 When the load of the secondary refrigeration compressor is controlled to remain unchanged; When T3>T 3设定温度 +T 3设定精度 When the secondary refrigeration compressor is loaded, When T3<T 3设定温度 -T 3设定精度 When the secondary refrigeration compressor is controlled to unload.

6. The control method of the passenger flow phase-changing cooling cycle oil and gas recovery system according to claim 4 is characterized in that: Also includes the steps: The actual test temperature of the fourth temperature sensor (110) is obtained as T4, and the outlet air temperature is set as T on the display operation module (114). 4设定温度 , set the control accuracy to T 4设定精度 ; When T 4设定温度 -T 4设定精度 ≤T4≤T 4设定温度 +T 4设定精度 When , the load of the three-stage refrigeration compressor is controlled to remain unchanged; When T4>T 4设定温度 +T 4设定精度 When the load of the three-stage refrigeration compressor is controlled; When T4<T 4设定温度 -T 4设定精度 When the 3rd stage refrigeration compressor is controlled to unload.

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