Low-temperature refrigerating unit for oil gas recovery
The dual cold box parallel design solves the problem of high oil and gas dew point during cold box defrosting, achieves energy-saving and continuous operation of the low-temperature refrigeration unit, and ensures the oil and gas condensation and cooling effect.
Patent Information
- Application Number
- CN202422565387.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-23
- Publication Date
- 2025-09-16
- Estimated Expiration
- 2034-10-23
AI Technical Summary
When the cold box of the existing low-temperature refrigeration unit is defrosting, the oil and gas dew point is higher than -25°C, which makes it impossible for the oil and gas to be effectively condensed, affecting the safety of downstream equipment and increasing energy consumption.
A double cold box structure is adopted, with cold box A and cold box B connected in parallel. Through the parallel double cold boxes and compressor design, the oil and gas are kept condensed and cooled while the cold box defrosts, and continuous operation is achieved by alternating the double cold boxes.
It achieves the goal of maintaining oil and gas condensation and cooling during the defrosting process of the cold box, ensuring that the oil and gas outlet temperature meets the requirements, reducing energy consumption and improving the safety and continuous operation capability of the equipment.
Smart Images
Figure CN223345683U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to a low-temperature refrigeration unit for oil and gas recovery. Background Art
[0002] The low-temperature refrigeration unit is mainly responsible for oil and gas condensation and cooling in the oil and gas recovery condensation adsorption process route, and the oil and gas mixed gas is graded and reduced to below its dew point for liquid collection and treatment. The oil and gas are sent to the cold box through the fan. The cold box is a finned evaporator. Generally, the temperature of the secondary cold box is below -25℃, and the evaporation temperature of the cold box is below -35℃. This requires the refrigeration unit to work under low temperature conditions. When the unit works under low temperature conditions, frost will form on the inner and outer surfaces of the cold box. If it is not defrosted in time, the working efficiency of the unit will be reduced. If the cold box is running to defrost, the temperature of the oil and gas from the cold box outlet will not meet the requirements.
[0003] At present, most oil and gas recovery condensation adsorption process routes use a single cold box to cool the oil and gas during the secondary condensation cooling process. When the cold box is defrosting, the gas with a dew point higher than -25°C condenses into liquid. Since the treatment of oil and gas is continuous, the oil and gas outlet temperature cannot be guaranteed at all. As a result, the oil and gas that should have been cooled at this stage are not processed and transferred to the downstream, resulting in an increase in the downstream refrigeration load, high energy consumption, no energy saving, and unsafe operation of the downstream units.
[0004] Therefore, those skilled in the art need an energy-saving, continuously operating low-temperature refrigeration unit with double cold boxes and oil and gas recovery. Utility Model Content
[0005] The purpose of this utility model is to solve the deficiencies of the above existing technologies and provide a low-temperature refrigeration unit for oil and gas recovery. While the cold box is defrosting, the upstream oil and gas will also be condensed and cooled at the same time, meeting the requirements of the oil and gas recovery process. The following is a specific solution:
[0006] A low-temperature refrigeration unit for oil and gas recovery includes a cold box A, a cold box B, an oil separator, a liquid reservoir, a compressor and an oil and gas pipe. The cold box A and the cold box B are connected in parallel with each other through the oil and gas pipe. The compressor is connected to the downstream of the cold box A and the cold box B respectively along the flow direction of the cooling oil. The oil separator is connected to the downstream of the compressor along the flow direction of the cooling oil. The oil separator is connected to the upstream of the cold box A and the cold box B respectively along the flow direction of the cooling oil; the liquid reservoir is connected to the cold box A and the cold box B respectively.
[0007] Furthermore, the A cold box is connected to the compressor through a first return air pipe, and the first return air pipe is connected in sequence to the A cold box return air solenoid valve, the intake filter and the vapor-liquid separator; the B cold box is connected to the compressor through a second return air pipe, and the second return air pipe is connected in sequence to the B cold box return air solenoid valve, the intake filter and the vapor-liquid separator.
[0008] Furthermore, the cold box A is also connected to the compressor through a first defrost pipe, and the first defrost pipe is connected to the cold box A defrost solenoid valve and oil separator in sequence; the cold box B is also connected to the compressor through a second defrost pipe, and the second defrost pipe is connected to the cold box B defrost solenoid valve and oil separator in sequence.
[0009] Furthermore, the A cold box is connected to the liquid reservoir through a first liquid supply pipe, and the first liquid supply pipe is sequentially provided with an A cold box expansion valve, an A cold box liquid supply solenoid valve, an economizer and a drying filter; the B cold box is connected to the liquid reservoir through a second liquid supply pipe, and the second liquid supply pipe is sequentially provided with a B cold box expansion valve, a B cold box liquid supply solenoid valve, an economizer and a drying filter.
[0010] Furthermore, the A cold box is also connected to the liquid reservoir through a third liquid supply pipe, and the third liquid supply pipe is connected to the A cold box defrost one-way valve. The B cold box is also connected to the liquid reservoir through a fourth liquid supply pipe, and the fourth liquid supply pipe is connected to the B cold box defrost one-way valve.
[0011] Furthermore, an air-cooled oil cooler is connected in parallel to the compressor.
[0012] Furthermore, an exhaust temperature sensor, a high pressure gauge, a high pressure sensor and a high and low pressure controller are connected to the pipeline between the compressor and the oil separator.
[0013] Furthermore, the compressor is a screw compressor.
[0014] Furthermore, an air cooling part is connected to the pipeline between the liquid reservoir and the oil separator, and a defrost guide valve is connected between the air cooling part and the oil separator. The air cooling part can provide a cooling compensation for the compressor. During normal operation, the defrost guide valve and the air cooling part are not opened.
[0015] Beneficial effect: By setting up the dual cold boxes and compressors in parallel, the cold boxes can meet the requirements of this level of oil and gas recovery process while defrosting, allowing the equipment to operate continuously for a longer period of time in an energy-saving manner. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1 This is a schematic diagram of the piping principle of a low-temperature refrigeration unit for oil and gas recovery;
[0017] In the figure: 1. Cold box A, 2. Cold box B, 3. Oil separator, 4. Liquid receiver, 5. Compressor, 6. Oil and gas pipe, 7. First return air pipe, 8. Second return air pipe, 9. Return air solenoid valve for cold box A, 10. Return air solenoid valve for cold box B, 11. Intake filter, 12. Vapor-liquid separator, 13. First defrost pipe, 14. Second defrost pipe, 15. Defrost solenoid valve for cold box A, 16. Defrost solenoid valve for cold box B, 17. First liquid supply pipe, 18. Second liquid supply pipe, 19. Expansion valve for cold box A, 20. Liquid supply for cold box A Solenoid valve, 21. B cold box expansion valve, 22. B cold box liquid supply solenoid valve, 23. Economizer, 24. Dry filter, 25. Third liquid supply pipe, 26. A cold box defrost check valve, 27. Fourth liquid supply pipe, 28. B cold box defrost check valve, 29. Air-cooled oil cooler, 30. Exhaust temperature sensor, 31. High pressure gauge, 32. High pressure sensor, 33. High and low pressure controllers, 34. Air cooling unit, 35. Defrost pilot valve, 36. Oil and gas duct control electric valve, 37. Low pressure gauge, 38. Low pressure sensor. DETAILED DESCRIPTION
[0018] In order to deepen the understanding of the present invention, the present invention will be further described in detail below with reference to embodiments and drawings. The embodiments are only used to explain the present invention and do not constitute a limitation on the scope of protection of the present invention.
[0019] Please see Figure 1 A low-temperature refrigeration unit for oil and gas recovery includes a cold box A 1, a cold box B 2, an oil separator 3, a liquid reservoir 4, a compressor 5 and an oil and gas pipe 6. The cold box A and the cold box B are connected in parallel with each other through the oil and gas pipe 6. The compressor 5 is connected to the downstream of the cold box A 1 and the cold box B 2 respectively along the flow direction of the cooling oil, the oil separator 3 is connected to the downstream of the compressor 5 along the flow direction of the cooling oil, and the oil separator 3 is connected to the upstream of the cold box A 1 and the cold box B 2 respectively along the flow direction of the cooling oil; the liquid reservoir 4 is connected to the cold box A 1 and the cold box B 2 respectively.
[0020] Cold box A 1 is connected to compressor 5 via a first return air pipe 7, which is sequentially connected to cold box A's return air solenoid valve 9, intake filter 11, and vapor-liquid separator 12. Cold box B 2 is connected to compressor 5 via a second return air pipe 8, which is sequentially connected to cold box B's return air solenoid valve, intake filter 11, and vapor-liquid separator 12. Cold box A 1 is also connected to compressor 5 via a first defrost pipe 13, which is sequentially connected to cold box A's defrost solenoid valve 15 and oil separator 3. Cold box B 2 is also connected to compressor 5 via a second defrost pipe 14, which is sequentially connected to cold box B's defrost solenoid valve 16 and oil separator 3. Cold box A 1 is connected to liquid storage 4 via a first liquid supply pipe 17, on which are sequentially provided an expansion valve 19 for cold box A, a liquid supply solenoid valve 20 for cold box A 1, an economizer 23 and a filter drier 24; cold box B 2 is connected to liquid storage 4 via a second liquid supply pipe 18, on which are sequentially provided an expansion valve 21 for cold box B, a liquid supply solenoid valve 22 for cold box B, an economizer 23 and a filter drier 24; cold box A 1 is also connected to liquid storage 4 via a third liquid supply pipe 25. The compressor 5 is connected to the liquid reservoir 4, the third liquid supply pipe 25 is connected to the A cold box defrost one-way valve 15, the B cold box 2 is also connected to the liquid reservoir 4 through the fourth liquid supply pipe 27, the fourth liquid supply pipe 27 is connected to the B cold box defrost one-way valve 16, an air-cooled oil cooler 29 is connected in parallel to the compressor 5, and the pipeline between the compressor 5 and the oil separator 3 is connected to the exhaust temperature sensor 30, the high-pressure gauge 31, the high-pressure sensor 32 and the high and low pressure controller 33. The compressor 5 is a screw compressor 5.
[0021] An air cooling portion 34 is also connected to the pipeline between the liquid receiver 4 and the oil separator 3 , and a defrost guide valve 35 is connected between the air cooling portion 34 and the oil separator 3 .
[0022] The pipelines between the compressor 5 and the vapor-liquid separator 12 are also connected to a low-pressure gauge 37 and a low-pressure sensor 38 .
[0023] For the purpose of greater clarity, the present invention is described in detail with reference to the following examples.
[0024] The model of screw compressor 5 is CSR190-ED, the model of the defrost pilot valve is RSABL-DN65, the model of the return air solenoid valve is AICS80, the model of the defrost solenoid valve is FDF12211, the model of the liquid supply solenoid valve is FDF12211, and the model of the defrost check valve is ACK-18.
[0025] When the unit is running, cold box A 1 defrosts first, and cold box B 2 operates. The process is as follows: the oil and gas duct control electric valve 36 on the cold box A 1 side is closed, that is, the air duct of cold box A 1 is closed, the other oil and gas duct control electric valve 36 is opened, the air duct of cold box B 2 is opened, the defrost pilot valve 35 is closed, the return air solenoid valve 9 of cold box A is closed, the defrost solenoid valve 15 of cold box A is opened, the liquid supply solenoid valve of cold box A is closed, the liquid supply solenoid valve of cold box B is opened 22, the return air solenoid valve 10 of cold box B is opened, and the defrost solenoid valve 16 of cold box B is closed. The high-temperature and high-pressure refrigerant gas enters the oil separator 3 through the exhaust pipe, and then enters the A cold box 1 through the A cold box defrost solenoid valve 15 to defrost the A cold box 1. After the defrost is completed, the refrigerant liquid enters the liquid reservoir 4 through the A cold box defrost one-way valve 26, and comes out of the liquid reservoir 4 through the B cold box liquid supply solenoid valve 22 to supply liquid to the B cold box 2. The oil and gas entering the B cold box 2 are cooled by throttling through the B cold box expansion valve 21. The evaporated low-temperature and low-pressure refrigerant gas enters the gas-liquid separator 12 through the B cold box return gas solenoid valve 10 and is sucked into the compressor 5 to complete the operation process of defrosting the A cold box 1 and cooling the B cold box 2. The double cold boxes are repeatedly used to achieve the cold box defrosting while meeting the cooling requirements of this level of oil and gas recovery process.
[0026] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model and are not limiting. Although the utility model is described in detail with reference to the preferred embodiments, ordinary technicians in this field should understand that the technical solution of the utility model can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the utility model, which should be included in the scope of the claims of the utility model.
Claims
1. A low-temperature refrigeration unit for oil and gas recovery, characterized in that: It includes a cold box A, a cold box B, an oil separator, a liquid reservoir, a compressor and an oil and gas pipe. The cold box A and the cold box B are connected in parallel with each other through the oil and gas pipe. The compressor is connected to the downstream of the cold box A and the cold box B respectively along the flow direction of the cooling oil. The oil separator is connected to the downstream of the compressor along the flow direction of the cooling oil. The oil separator is connected to the upstream of the cold box A and the cold box B respectively along the flow direction of the cooling oil; the liquid reservoir is connected to the cold box A and the cold box B respectively.
2. A low-temperature refrigeration unit for oil and gas recovery according to claim 1, characterized in that: The A cold box is connected to the compressor through a first return air pipe, and the first return air pipe is connected in sequence to the A cold box return air solenoid valve, the intake air filter and the vapor-liquid separator; the B cold box is connected to the compressor through a second return air pipe, and the second return air pipe is connected in sequence to the B cold box return air solenoid valve, the intake air filter and the vapor-liquid separator.
3. The low-temperature refrigeration unit for oil and gas recovery according to claim 1, characterized in that: The A cold box is also connected to the compressor through a first defrost pipe, and the first defrost pipe is connected to the A cold box defrost solenoid valve and the oil separator in sequence; the B cold box is also connected to the compressor through a second defrost pipe, and the second defrost pipe is connected to the B cold box defrost solenoid valve and the oil separator in sequence.
4. The low-temperature refrigeration unit for oil and gas recovery according to claim 1, characterized in that: The A cold box is connected to the liquid reservoir through a first liquid supply pipe, on which the A cold box expansion valve, the A cold box liquid supply solenoid valve, the economizer and the drying filter are sequentially provided; the B cold box is connected to the liquid reservoir through a second liquid supply pipe, on which the B cold box expansion valve, the B cold box liquid supply solenoid valve, the economizer and the drying filter are sequentially provided.
5. The low-temperature refrigeration unit for oil and gas recovery according to claim 1, characterized in that: The A cold box is also connected to the liquid reservoir through a third liquid supply pipe, and the third liquid supply pipe is connected to the A cold box defrost one-way valve. The B cold box is also connected to the liquid reservoir through a fourth liquid supply pipe, and the fourth liquid supply pipe is connected to the B cold box defrost one-way valve.
6. The low-temperature refrigeration unit for oil and gas recovery according to claim 1, characterized in that: An air-cooled oil cooler is connected in parallel to the compressor.
7. The low-temperature refrigeration unit for oil and gas recovery according to claim 1, characterized in that: An exhaust temperature sensor, a high pressure gauge, a high pressure sensor and high and low pressure controllers are connected on the pipeline between the compressor and the oil separator.
8. The low-temperature refrigeration unit for oil and gas recovery according to claim 1, characterized in that: The compressor is a screw compressor.
9. A low-temperature refrigeration unit for oil and gas recovery according to any one of claims 1 to 8, characterized in that: An air cooling part is also connected to the pipeline between the liquid storage device and the oil separator, and a defrost guide valve is connected between the air cooling part and the oil separator.