A control method for a plate-fin oil and gas condenser

Abstract

The application discloses a control method of a plate-fin oil-gas condenser, which comprises the following steps: controlling a first switch valve and a third switch valve to be opened, and controlling a second switch valve and a fourth switch valve to be closed, and the plate-fin oil-gas condenser executes a condensing mode; acquiring real-time pressure values fed back by a second pressure sensor and a third pressure sensor and calculating a real-time pressure difference value between the two; comparing the real-time pressure difference value with a preset pressure difference setting value P0, and when an execution condition is met, executing a defrosting mode; acquiring a real-time temperature value fed back by a second temperature sensor and setting the real-time temperature value as T2; comparing the real-time temperature value T2 with a set temperature value T02, and judging whether the plate-fin oil-gas condenser returns to the condensing mode according to a comparison result; the control method can execute the defrosting mode according to a comparison result of the real-time pressure difference value and the preset pressure difference value, realizes timely defrosting and clean defrosting, avoids the problem that the plate-fin oil-gas condenser cannot normally operate, and improves the operation stability and reliability of the plate-fin oil-gas condenser.

Description

Technical Field

[0001] This invention relates to the field of oil and gas condensation and liquefaction technology, and in particular to a control method for a plate-fin type oil and gas condenser. Background Technology

[0002] Oil-gas condensers are used to condense and liquefy volatile organic compounds in oil and gas, such as VOCs. Since the condensation temperature of most VOCs is much lower than 0°C and VOCs contain moisture, existing oil-gas condensers are prone to frosting when operating in condensation mode, i.e., when condensing and liquefying oil and gas. Frosted oil-gas condensers often fail to operate normally, and when there is too much frost on the heat exchanger surface, it may even crack the heat exchanger, causing damage to the oil-gas condenser and preventing it from continuing to work.

[0003] It is evident that existing technologies still need improvement and enhancement. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of this invention is to provide a control method for a plate-fin oil-gas condenser, which can achieve timely and clean defrosting, and has the advantages of high operational stability and good working reliability.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A control method for a plate-fin oil-gas condenser, the plate-fin oil-gas condenser comprising a shell, a control device, and a first switching valve, a second switching valve, a third switching valve, a fourth switching valve, a second pressure sensor, a third pressure sensor, and a second temperature sensor, all electrically connected to the control device. A liquid inlet and a gas outlet are provided on one side of the shell, and an oil-gas inlet and an oil-gas outlet are provided on the top of the shell. One end of the first switching valve is connected to a liquid pipe after the refrigeration system filter, and one end of the second switching valve is connected to a liquid pipe after the refrigeration system condenser. The other ends of the first and second switching valves are respectively connected to the liquid inlet. One end of the third and fourth switching valves are respectively connected to the gas outlet. The other end of the third switching valve is connected to the compressor's suction pipe, and the other end of the fourth switching valve is connected to the compressor's discharge pipe. The second pressure sensor is located at the oil-gas inlet, the third pressure sensor is located at the oil-gas outlet, and the second temperature sensor is located on the connection line between the first switching valve and the liquid inlet. The control method includes:

[0007] The first and third switching valves are opened, and the second and fourth switching valves are closed; the plate-fin oil-gas condenser operates in condensation mode.

[0008] Obtain the real-time pressure values ​​fed back by the second and third pressure sensors, and set them as P2 and P3 respectively. Calculate the real-time pressure difference value based on P2 and P3.

[0009] When P2-P3≤P0, the first, second, third, and fourth switching valves remain in their operating states.

[0010] When P2-P3>P0, the first and third switching valves are closed, and the second and fourth switching valves are opened, and the plate-fin oil-gas condenser performs defrosting mode.

[0011] Obtain the real-time temperature value fed back by the second temperature sensor and set it as T2;

[0012] Compare the real-time temperature value T2 with the set temperature value T02, and determine whether to return to condensation mode based on the comparison result.

[0013] In the control method for the plate-fin type oil-gas condenser, the step of comparing the real-time temperature value T2 with the set temperature value T02 and determining whether to return to condensation mode based on the comparison result specifically includes the following steps:

[0014] When T2≤T02, the first, second, third, and fourth switching valves remain in their operating states.

[0015] When T2 > T02, the first and third switching valves are opened, and the second and fourth switching valves are closed, and the plate-fin oil-gas condenser returns to the condensation mode.

[0016] In the control method for the plate-fin oil-gas condenser, the plate-fin oil-gas condenser further includes a first pressure sensor, a first temperature sensor, and an expansion valve, which are electrically connected to the control device respectively; the expansion valve is disposed on the connecting pipeline between the first switching valve and the liquid inlet; the first pressure sensor and the first temperature sensor are respectively disposed on the connecting pipeline between the third switching valve and the gas outlet; after controlling the first switching valve and the third switching valve to open, and controlling the second switching valve and the fourth switching valve to close, the method further includes the following steps:

[0017] Control the expansion valve to open;

[0018] Obtain the real-time pressure value fed back by the first pressure sensor, and obtain the saturation temperature TP corresponding to the real-time pressure value;

[0019] Obtain the real-time temperature value fed back by the first temperature sensor, set it as T1, and calculate the difference between the real-time saturation temperature TP and the real-time temperature value T1.

[0020] Obtain the preset temperature value T01 and the preset control precision ΔT;

[0021] The operating state of the expansion valve is adjusted based on the comparison between the difference between the real-time saturation temperature TP and the real-time temperature value T1, the set temperature value T01, and the set control accuracy ΔT.

[0022] In the control method for the plate-fin oil-gas condenser, adjusting the operating state of the expansion valve based on the comparison result between the difference between the real-time saturation temperature TP and the real-time temperature value T1, the set temperature value T01, and the set control accuracy ΔT specifically includes:

[0023] When T01-ΔT≤TP-T1≤T01+ΔT, the control expansion valve remains in its operating state.

[0024] When TP-T1>T01+ΔT, the opening degree of the control expansion valve increases;

[0025] When TP-T1 < T01-ΔT, the opening of the control expansion valve is reduced.

[0026] In the control method of the plate-fin oil-gas condenser, multiple heat exchange plates are arranged inside the shell, the bottom ends of the multiple heat exchange plates are respectively connected to the liquid inlet interface, and the top ends of the multiple heat exchange plates are respectively connected to the gas outlet interface; a refrigerant flow channel is arranged inside the heat exchange plate, and the refrigerant flow channel is a serpentine channel, a herringbone channel, a spherical channel, or a straight channel; fins are arranged on the outer surface of the heat exchange plate.

[0027] In the control method of the plate-fin oil-gas condenser, a liquid distributor and a gas collecting pipe are also provided inside the shell. The bottom ends of the multiple heat exchange plates are respectively connected to the liquid inlet through the liquid distributor, and the top ends of the multiple heat exchange plates are respectively connected to the gas outlet through the gas collecting pipe.

[0028] In the control method of the plate-fin oil-gas condenser, the shell is further provided with multiple baffles, the gaps between the multiple baffles are distributed between the multiple fins, and adjacent baffles are arranged vertically.

[0029] In the control method of the plate-fin oil-gas condenser, the heat exchange plate further includes an inlet, a first heat exchange fin, a second heat exchange fin, and an outlet. The first heat exchange fin is connected to the liquid inlet interface through the inlet and to the second heat exchange fin through the refrigerant flow channel. The second heat exchange fin is connected to the gas outlet interface through the outlet.

[0030] In the control method of the plate-fin oil-gas condenser, baffles are respectively provided at both ends of the fins.

[0031] In the control method of the plate-fin oil-gas condenser, the shell includes a first end cover, a second end cover, a first tube sheet, a second tube sheet, and a tube body. The first end cover is connected to one end of the tube body through the first tube sheet, and the second end cover is connected to the other end of the tube body through the second tube sheet. The liquid inlet and the gas outlet are respectively disposed on the first end cover, and the oil-gas inlet and the oil-gas outlet are respectively disposed on the top of the tube body. One end of the multiple heat exchange plates is respectively connected to the first tube sheet, and the other end of the multiple heat exchange plates is respectively connected to the second tube sheet. The bottom of the tube body is also provided with an oil-gas condensate liquid outlet and a mounting base.

[0032] Beneficial effects:

[0033] This invention provides a control method for a plate-fin oil-gas condenser. It can execute a defrosting mode based on a comparison between a real-time differential pressure value and a preset differential pressure value, achieving timely and clean defrosting. This avoids frost buildup that could prevent the plate-fin oil-gas condenser from malfunctioning, improving its stability and reliability. Furthermore, when executing the defrosting mode, it can return to the condensation mode based on a comparison between a real-time temperature value T2 and a preset temperature value, enhancing the intelligence of the plate-fin oil-gas condenser during operation and ensuring continuous operation, thereby improving the user experience. Attached Figure Description

[0034] Figure 1 A first logic flowchart of the control method provided by the present invention;

[0035] Figure 2 A logic flowchart of one embodiment of step S500 provided by the present invention;

[0036] Figure 3 A second logic flowchart of the control method provided by the present invention;

[0037] Figure 4 A logic flowchart of an embodiment of step S650 provided by the present invention;

[0038] Figure 5 A front view of the internal structure of the plate-fin type oil-gas condenser provided by the present invention;

[0039] Figure 6 A top view of the internal structure of the plate-fin type oil-gas condenser provided by the present invention;

[0040] Figure 7 A bottom view of the internal structure of the plate-fin type oil-gas condenser provided by the present invention.

[0041] Figure 8 The system structure diagram of the plate-fin type oil-gas condenser provided by the present invention.

[0042] Key component symbols: 1-House, 11-First end cap, 12-Second end cap, 13-First tube sheet, 14-Second tube sheet, 15-Tube body, 16-Mounting base, 21-Liquid inlet, 22-Gas outlet, 23-Oil / gas inlet, 24-Oil / gas outlet, 25-Oil / gas condensate outlet, 31-Heat exchange plate, 32-Liquid distributor, 33-Gas collecting pipe, 34-Fins, 35-Baffle plate, 36-Baffle, 4-Control device, 51-First switching valve, 52-Second switching valve, 53-Third switching valve, 54-Fourth switching valve, 55-Expansion valve, 61-First temperature sensor, 62-Second temperature sensor, 63-First pressure sensor, 64-Second pressure sensor, 65-Third pressure sensor. Detailed Implementation

[0043] This invention provides a control method for a plate-fin type oil-gas condenser. To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0044] In the description of this invention, it should be understood that the terms "top," "bottom," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention and simplifying the description, and should not be construed as limiting this invention; in addition, the terms "installation," "connection," etc. should be interpreted broadly, and those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0045] Please see Figures 1 to 8This invention provides a control method for a plate-fin oil-gas condenser. The plate-fin oil-gas condenser includes a housing 1, a control device 4, and a first switching valve 51, a second switching valve 52, a third switching valve 53, a fourth switching valve 54, a second pressure sensor 64, a third pressure sensor 65, and a second temperature sensor 62, all electrically connected to the control device 4. A liquid inlet 21 and a gas outlet 22 are provided on one side of the housing 1, and an oil-gas inlet 23 and an oil-gas outlet 24 are provided on the top of the housing 1. One end of the first switching valve 51 is used to connect to the liquid pipe after the filter of the refrigeration system, and one end of the second switching valve 52 is used to connect to the condenser of the refrigeration system. The liquid pipe is connected to the liquid inlet 21, with the other ends of the first switching valve 51 and the second switching valve 52 respectively connected to the liquid inlet 21; one end of the third switching valve 53 and one end of the fourth switching valve 54 are respectively connected to the gas outlet 22, the other end of the third switching valve 53 is used to connect to the compressor's suction pipe, and the other end of the fourth switching valve 54 is used to connect to the compressor's discharge pipe; the second pressure sensor 64 is located at the oil and gas inlet 23, the third pressure sensor 65 is located at the oil and gas outlet 24, and the second temperature sensor 62 is located on the connecting pipe between the first switching valve 51 and the liquid inlet 21; the control method includes:

[0046] S100: Control the first switching valve 51 and the third switching valve 53 to open, and control the second switching valve 52 and the fourth switching valve 54 to close; the plate-fin oil-gas condenser executes the condensation mode;

[0047] S200: Obtain the real-time pressure values ​​fed back by the second pressure sensor 64 and the third pressure sensor 65, and set them as P2 and P3 respectively. Calculate the real-time pressure difference value based on P2 and P3.

[0048] S310. When P2-P3≤P0, control the first switching valve 51, the second switching valve 52, the third switching valve 53 and the fourth switching valve 54 to maintain their working state unchanged.

[0049] S320. When P2-P3>P0, control the first switching valve 51 and the third switching valve 53 to close, and control the second switching valve 52 and the fourth switching valve 54 to open, so that the plate-fin oil-gas condenser can perform defrosting mode.

[0050] S400: Obtain the real-time temperature value fed back by the second temperature sensor 62 and set it as T2;

[0051] S500: Compare the real-time temperature value T2 with the set temperature value T02, and determine whether to return to condensation mode based on the comparison result.

[0052] The control method for the plate-fin oil-gas condenser disclosed in this application can execute a defrosting mode based on the comparison result of the real-time differential pressure value and the preset differential pressure value, thereby achieving timely and clean defrosting and avoiding the plate-fin oil-gas condenser from failing to operate normally due to frost problems, thus improving the stability and reliability of the plate-fin oil-gas condenser during operation. In addition, when the defrosting mode is executed, the condensing mode can be returned based on the comparison result of the real-time temperature value T2 and the preset temperature value, thereby improving the intelligence of the plate-fin oil-gas condenser during operation, ensuring the continuity of the plate-fin oil-gas condenser during operation, and thus improving the user experience.

[0053] During the actual operation of the plate-fin oil-gas condenser, if frost forms inside the condenser, the frost will block the ventilation gaps, and the resistance to oil and gas flow will gradually increase. When the pressure difference between the real-time pressure values ​​fed back by the second pressure sensor 64 and the third pressure sensor 65 is greater than or equal to the preset pressure difference value, it indicates that frost has covered the surface of the fins 34. At this time, hot gas bypass defrosting is required. When bypass defrosting is performed, the first switch valve 51 and the third switch valve 53 are closed, and the second switch valve 52 and the fourth switch valve 54 are opened. The high-temperature gas output from the compressor exhaust pipe enters the housing 1 through the fourth switch valve 54 and the gas outlet 22. The gas after heat exchange condenses into liquid and is output to the liquid pipe after the condenser of the refrigeration system through the liquid inlet 21 and the second switch valve 52.

[0054] Further, please refer to Figure 2 and Figure 5 The comparison of the real-time temperature value T2 with the set temperature value T02, and the determination of whether to return to condensation mode based on the comparison result, specifically includes the following steps:

[0055] S510. When T2≤T02, control the first switching valve 51, the second switching valve 52, the third switching valve 53 and the fourth switching valve 54 to maintain their working state unchanged.

[0056] S520. When T2 > T02, control the first switching valve 51 and the third switching valve 53 to open, and control the second switching valve 52 and the fourth switching valve 54 to close, so that the plate-fin oil-gas condenser returns to the condensation mode.

[0057] When the plate-fin oil-gas condenser is in defrost mode, hot gas bypass is used for defrosting. Initially, due to the large amount of frost, the refrigerant temperature at the outlet of liquid inlet 21 is low. As the defrosting time increases, the refrigerant temperature at the outlet of liquid inlet 21 gradually rises. When T2 > T02, it indicates that the plate-fin oil-gas condenser has completed defrosting, and the defrosting can be stopped, returning to condensation mode to re-condense and liquefy the oil and gas. When the plate-fin oil-gas condenser is in condensation mode, low-temperature refrigerant liquid is input from liquid inlet 21 to liquid distributor 32. The refrigerant is evenly distributed into multiple heat exchange plates 31 by the liquid distributor 32. The refrigerant flows along the refrigerant channel in the heat exchange plate 31 to the gas collecting pipe 33, and then exits the plate-fin oil-gas condenser through the gas outlet 22. The oil and gas to be condensed and liquefied enter the plate-fin oil-gas condenser through the oil and gas inlet 23 and exchange heat with the refrigerant in the multiple heat exchange plates 31. The oil and gas fluid is rectified by the baffle plate 35. The oil and gas after heat exchange is partially discharged through the oil and gas outlet 24, and partially condensed into liquid and discharged through the oil and gas condensate liquid outlet 25.

[0058] Further, please refer to Figure 3 and Figure 5 The plate-fin type oil-gas condenser further includes a first pressure sensor 63, a first temperature sensor 61, and an expansion valve 55, which are electrically connected to the control device 4 respectively; the expansion valve 55 is disposed on the connecting pipeline between the first switching valve 51 and the liquid inlet 21; the first pressure sensor 63 and the first temperature sensor 61 are respectively disposed on the connecting pipeline between the third switching valve 53 and the gas outlet 22; after controlling the first switching valve 51 and the third switching valve 53 to open, and controlling the second switching valve 52 and the fourth switching valve 54 to close, the following steps are also included:

[0059] S610, control the expansion valve 55 to open;

[0060] S620: Obtain the real-time pressure value fed back by the first pressure sensor 63, and obtain the saturation temperature TP corresponding to the real-time pressure value;

[0061] S630. Obtain the real-time temperature value fed back by the first temperature sensor 61, set it as T1, and calculate the difference between the real-time saturation temperature TP and the real-time temperature value T1.

[0062] S640: Obtain the preset temperature value T01 and the preset control accuracy ΔT;

[0063] S650: Adjust the working state of expansion valve 55 based on the comparison result between the difference between real-time saturation temperature TP and real-time temperature value T1, the set temperature value T01, and the set control accuracy ΔT.

[0064] The control method for the plate-fin oil-gas condenser disclosed in this application can also adjust the working state of the expansion valve 55 according to the comparison result between the difference between the real-time saturation temperature TP and the real-time temperature value T1, the set temperature value T01, and the set control accuracy ΔT, to ensure sufficient refrigerant in the plate-fin oil-gas condenser, thereby ensuring the condensation and liquefaction effect of oil and gas and improving the stability and reliability of the plate-fin oil-gas condenser during operation.

[0065] Further, please refer to Figure 4 and Figure 5 The adjustment of the operating state of the expansion valve 55 based on the comparison between the difference between the real-time saturation temperature TP and the real-time temperature value T1, the set temperature value T01, and the set control precision ΔT specifically includes:

[0066] S651. When T01-ΔT≤TP-T1≤T01+ΔT, control the expansion valve 55 to remain in the same working state.

[0067] S652. When TP-T1>T01+ΔT, the opening degree of the control expansion valve 55 increases.

[0068] S653. When TP-T1 < T01-ΔT, the opening of the expansion valve 55 is reduced.

[0069] When the plate-fin oil-gas condenser is in defrost mode, if TP-T1 > T01 + ΔT, it indicates that the refrigerant flow in the plate-fin oil-gas condenser is insufficient and the superheat at the outlet 22 of the oil-gas condenser is relatively high. The expansion valve 55 needs to be opened wider to increase the refrigerant flow. If TP-T1 < T01 - ΔT, it indicates that the refrigerant flow in the plate-fin oil-gas condenser is too high and the superheat at the outlet 22 of the oil-gas condenser is relatively low. The expansion valve 55 needs to be closed to reduce the refrigerant flow. If the superheat is too low and the flow is too high, some liquid refrigerant cannot evaporate into gas, and the liquid refrigerant directly enters the compressor's compression chamber. Since liquid is incompressible, this will damage the compressor. If the superheat is too high and the flow is too low, all the liquid refrigerant will evaporate into gas, and the compressor's suction temperature will be relatively high. Although the gas will not damage the compressor, the excessively high suction temperature will lead to insufficient compressor cooling, resulting in an excessively high compressor discharge temperature, which will ultimately damage the compressor.

[0070] Further, please refer to Figures 5 to 7The housing 1 contains multiple heat exchange plates 31, the bottom ends of which are connected to the liquid inlet 21 and the top ends of which are connected to the gas outlet 22. Each heat exchange plate 31 contains a refrigerant channel, which may be a serpentine channel, a herringbone channel, a spherical channel, or a straight channel. The outer surface of the heat exchange plate 31 is provided with fins 34.

[0071] In this embodiment, multiple heat exchange plates 31 are provided, each containing a refrigerant flow channel. The refrigerant flows naturally along these channels after entering the heat exchange plate 31, without needing to pass through deflectors. This avoids the uneven distribution problem caused by refrigerant redistribution at multi-pass deflectors and also prevents poor oil return due to insufficient flow velocity at multi-pass deflectors, thus improving the oil return reliability and heat exchange uniformity of the plate-fin oil-gas condenser. Furthermore, using heat exchange plates 31 significantly increases the heat exchange contact area between the refrigerant and the oil / gas, optimizing it from line contact to surface contact, greatly improving the heat exchange effect of the plate-fin oil-gas condenser. The outer surface of the heat exchange plates 31 is also provided with fins 34, expanding the heat exchange area. Compared with the prior art, the heat exchange area of ​​the heat exchange plates 31 in this application is increased by 2-3 times, effectively improving the condensation and liquefaction effect of the plate-fin oil-gas condenser.

[0072] Further, please refer to Figures 5 to 7 The housing 1 is further provided with a liquid distributor 32 and a gas collecting pipe 33. The bottom ends of the multiple heat exchange plates 31 are respectively connected to the liquid inlet port 21 through the liquid distributor 32, and the top ends of the multiple heat exchange plates 31 are respectively connected to the gas outlet port 22 through the gas collecting pipe 33. In this embodiment, the liquid distributor 32 includes a liquid distributor and multiple liquid distributor pipes. The liquid distributor is connected to the liquid inlet port 21, and the multiple liquid distributor pipes are connected to the bottom ends of the multiple heat exchange plates 31 one by one. The liquid distributor 32 evenly distributes the refrigerant into each heat exchange plate 31, which greatly improves the uniformity of refrigerant distribution and makes full use of each heat exchange plate 31, thus greatly improving the heat exchange efficiency of the plate-fin oil-gas condenser.

[0073] Further, please refer to Figures 5 to 7 The housing 1 is also provided with a plurality of baffles 35, which are spaced apart between the plurality of fins 34, and adjacent baffles 35 are arranged vertically; specifically, when any baffle 35 is fixedly connected to the top inner wall of the housing 1, the adjacent baffle 35 is fixedly connected to the bottom inner wall of the housing 1; in this embodiment, the baffles 35 are fixedly connected to the housing 1.

[0074] By setting baffles 35 inside the shell 1, the oil and gas fluids can be orderly and regulated, so that the two heat exchange fluids can flow in an orderly manner, achieving a stable heat exchange temperature difference, thereby greatly improving the heat exchange efficiency of the plate-fin oil and gas condenser.

[0075] Further, please refer to Figures 5 to 7 The heat exchange plate 31 further includes an inlet, a first heat exchange fin, a second heat exchange fin, and an outlet. The first heat exchange fin is connected to the liquid inlet interface 21 through the inlet and to the second heat exchange fin through the refrigerant flow channel. The second heat exchange fin is connected to the gas outlet interface 22 through the outlet. When the plate-fin oil-gas condenser is in condensation mode, the refrigerant is input into the housing 1 through the liquid inlet interface 21, and then evenly distributed to each heat exchange plate 31 through the liquid distribution system. The refrigerant enters the first heat exchange fin through the inlet, flows along the refrigerant flow channel to the second heat exchange fin, and then flows into the gas collecting pipe 33 through the outlet, completing the heat exchange process with the oil and gas.

[0076] Further, please refer to Figures 5 to 7 The two ends of the fin 34 are respectively provided with baffles 36, which are used to limit the movement position of the fin 34 and can also play a heat conduction role, further increasing the heat exchange area of ​​the plate-fin oil-gas condenser and improving the heat exchange performance of the plate-fin oil-gas condenser; in this embodiment, the baffles 36 are respectively welded to the two ends of the fin 34.

[0077] Further, please refer to Figures 5 to 7 The housing 1 includes a first end cap 11, a second end cap 12, a first tube sheet 13, a second tube sheet 14, and a tube body 15. The first end cap 11 is connected to one end of the tube body 15 through the first tube sheet 13, and the second end cap 12 is connected to the other end of the tube body 15 through the second tube sheet 14. The liquid inlet 21 and the gas outlet 22 are respectively disposed on the first end cap 11, and the oil / gas inlet 23 and the oil / gas outlet 24 are respectively disposed on the top of the tube body 15. One end of each of the multiple heat exchange plates 31 is connected to the first tube sheet 13. The other ends of the multiple heat exchange plates 31 are respectively connected to the second tube sheet 14; the bottom of the tube body 15 is also provided with an oil and gas condensate outlet 25 and a mounting base 16; in this embodiment, the first tube sheet 13 is welded to the first end cap 11 and the tube body 15 respectively; the second tube sheet 14 is welded to the second end cap 12 and the tube body 15 respectively; the heat exchange plates 31 are respectively connected to the inside of the first tube sheet 13 and the second tube sheet 14; the oil and gas condensate outlet 25 is integrally formed with the shell 1, and the mounting base 16 is welded to the shell 1.

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

Claims

1. A control method for a plate-fin type oil-gas condenser, characterized in that, The plate-fin type oil-gas condenser includes a shell, a control device, and a first switching valve, a second switching valve, a third switching valve, a fourth switching valve, a second pressure sensor, a third pressure sensor, and a second temperature sensor, all electrically connected to the control device. A liquid inlet and a gas outlet are provided on one side of the shell, and an oil-gas inlet and an oil-gas outlet are provided on the top of the shell. One end of the first switching valve is connected to the liquid pipe after the refrigeration system filter, and one end of the second switching valve is connected to the liquid pipe after the refrigeration system condenser. The other ends of the first and second switching valves are respectively connected to the liquid inlet. One end of the third switching valve and one end of the fourth switching valve are respectively connected to the gas outlet port. The other end of the third switching valve is used to connect to the compressor's suction pipe, and the other end of the fourth switching valve is used to connect to the compressor's discharge pipe. The second pressure sensor is located at the oil and gas inlet, the third pressure sensor is located at the oil and gas outlet, and the second temperature sensor is located on the connecting pipe between the first switching valve and the liquid inlet port. The system also includes a first pressure sensor, a first temperature sensor, and an expansion valve, all electrically connected to the control device. The expansion valve is located on the connecting pipe between the first switching valve and the liquid inlet port. The first pressure sensor and the first temperature sensor are respectively installed on the connecting pipe between the third switching valve and the air outlet; the control method includes: The first and third switching valves are opened, and the second and fourth switching valves are closed; the plate-fin oil-gas condenser operates in condensation mode. The expansion valve is opened; the real-time pressure value fed back by the first pressure sensor is obtained, and the saturation temperature TP corresponding to the real-time pressure value is obtained; the real-time temperature value fed back by the first temperature sensor is obtained, set as T1, and the difference between the real-time saturation temperature TP and the real-time temperature value T1 is calculated; the preset temperature value T01 and the preset control accuracy ΔT are obtained; the working state of the expansion valve is adjusted according to the comparison result between the difference between the real-time saturation temperature TP and the real-time temperature value T1 and the preset temperature value T01 and the preset control accuracy ΔT. The real-time pressure values ​​fed back by the second and third pressure sensors are obtained and set as P2 and P3 respectively. The real-time pressure difference value is calculated based on P2 and P3, and the real-time pressure difference value is compared with the preset pressure difference setting value P0. When P2-P3≤P0, the first, second, third, and fourth switching valves remain in their operating states. When P2-P3>P0, the first and third switching valves are closed, and the second and fourth switching valves are opened, and the plate-fin oil-gas condenser performs defrosting mode. Obtain the real-time temperature value fed back by the second temperature sensor and set it as T2; Compare the real-time temperature value T2 with the set temperature value T02, and determine whether to return to condensation mode based on the comparison result.

2. The control method for a plate-fin type oil-gas condenser according to claim 1, characterized in that, The process of comparing the real-time temperature value T2 with the set temperature value T02 and determining whether to return to condensation mode based on the comparison result includes the following steps: When T2≤T02, the first, second, third, and fourth switching valves remain in their operating states. When T2 > T02, the first and third switching valves are opened, and the second and fourth switching valves are closed, and the plate-fin oil-gas condenser returns to the condensation mode.

3. The control method for a plate-fin type oil-gas condenser according to claim 1, characterized in that, The adjustment of the expansion valve's operating state based on the comparison between the difference between the real-time saturation temperature TP and the real-time temperature value T1, the set temperature value T01, and the set control precision ΔT specifically includes: When T01-ΔT≤TP-T1≤T01+ΔT, the control expansion valve remains in its operating state. When TP-T1>T01+ΔT, the opening degree of the control expansion valve increases; When TP-T1 < T01-ΔT, the opening of the control expansion valve is reduced.

4. The control method for a plate-fin type oil-gas condenser according to claim 1, characterized in that, The housing contains multiple heat exchange plates, the bottom ends of which are connected to the liquid inlet and the top ends of which are connected to the gas outlet. Each heat exchange plate contains a refrigerant channel, which may be a serpentine channel, a herringbone channel, a spherical channel, or a straight channel. The outer surface of the heat exchange plate is provided with fins.

5. The control method for a plate-fin type oil-gas condenser according to claim 4, characterized in that, The housing is also equipped with a liquid distributor and a gas collecting pipe. The bottom ends of the multiple heat exchange plates are respectively connected to the liquid inlet through the liquid distributor, and the top ends of the multiple heat exchange plates are respectively connected to the gas outlet through the gas collecting pipe.

6. The control method for a plate-fin type oil-gas condenser according to claim 4, characterized in that, The housing is also provided with multiple baffles, the gaps between the multiple baffles are distributed between the multiple fins, and adjacent baffles are arranged vertically.

7. The control method for a plate-fin type oil-gas condenser according to claim 6, characterized in that, The heat exchange plate further includes an inlet, a first heat exchange plate, a second heat exchange plate, and an outlet. The first heat exchange plate is connected to the liquid inlet interface through the inlet and to the second heat exchange plate through the refrigerant flow channel. The second heat exchange plate is connected to the gas outlet interface through the outlet.

8. The control method for a plate-fin type oil-gas condenser according to claim 4, characterized in that, Baffles are provided at both ends of the fins.

9. The control method for a plate-fin type oil-gas condenser according to claim 4, characterized in that, The housing includes a first end cap, a second end cap, a first tube sheet, a second tube sheet, and a tube body. The first end cap is connected to one end of the tube body through the first tube sheet, and the second end cap is connected to the other end of the tube body through the second tube sheet. The liquid inlet and the gas outlet are respectively disposed on the first end cap, and the oil and gas inlet and the oil and gas outlet are respectively disposed on the top of the tube body. One end of the multiple heat exchange plates is respectively connected to the first tube sheet, and the other end of the multiple heat exchange plates is respectively connected to the second tube sheet. The bottom of the tube body is also provided with an oil and gas condensate outlet and a mounting base.

Images