Method for reducing liquid carried at inlet of screw type propylene compressor

Abstract

The invention relates to the technical field of screw compressors, and particularly discloses a method for reducing liquid carried at an inlet of a screw propylene compressor, which comprises the following steps of: adding a three-way valve on a pipeline from a propylene flash tank to a propylene subcooler, and leading out a liquid propylene pipeline to the lower part of a compressor inlet suction buffer tank; a floating head type U-shaped heat exchange tube bundle and a seal head with a partition plate are additionally arranged at the bottom, one side of an inlet is connected with liquid propylene, the liquid propylene enters the U-shaped heat exchange tube bundle to exchange heat with propylene liquid at the bottom of an air suction buffer tank, the liquid propylene with the liquid is heated into gas propylene to enter an inlet of a compressor, the liquid carrying condition is reduced, and the safety and stability of unit operation are improved; liquid propylene after heat exchange is led out from the other side of the bottom of the air suction buffer tank, is connected and converged with a main pipeline behind a three-way valve and then enters a propylene subcooler, the flow of the liquid propylene is adjusted to a U-shaped heat exchange pipe through the temperature value of an outlet of the U-shaped heat exchange pipe of the air suction buffer tank and the three-way valve, temperature setting is automatically adjusted, and energy conservation and consumption reduction are achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of screw compressors, and particularly relates to a method for reducing liquid carry - over at the inlet of a screw - type propylene compressor. Background Art

[0002] The working process of a screw compressor consists of steps of suction, sealed transportation, compression with oil injection, and exhaust. A buffer tank is provided at the inlet for stable pressure gas supply. The outlet oil - separator separates and recovers the lubricating oil sprayed into the compressor from the gaseous propylene. The load increase and decrease of the compressor are controlled by an energy - regulating slide valve, enabling automatic regulation. The working principle of propylene refrigeration is the propylene refrigeration cycle process of compression → condensation → decompression → evaporation. Using a propylene compressor, gaseous propylene is pressurized to about 1.73 MPaG. The superheated gaseous propylene is condensed into saturated liquid propylene by circulating cooling water. The condensation temperature of propylene is about 40°C. Then, using the throttling and expansion principle, the liquid propylene is depressurized in a throttle valve, reducing its liquid - phase boiling point. Through evaporation, the liquid propylene evaporates into gaseous propylene in a heat exchanger while absorbing the heat of the user, achieving the purpose of refrigeration and temperature reduction.

[0003] Currently, in order to provide 2536 - 2778 KW of cooling capacity for the low - temperature methanol washing process, an additional motor - driven screw compressor C04701 is required as a standby for the centrifugal propylene compressor C04301. The design parameters of the screw compressor are as follows: inlet pressure of the compressor is 0.007 MPaG, temperature is - 46°C, inlet propylene gas volume is 30975 kg / h, propylene gas volume in the make - up section is 12010 kg / h, outlet pressure is 1.73 MPaG, outlet temperature is 82.7°C, and the main motor of the compressor is 10 KV with a rated power of 3150 KW. During the start - up process of the screw compressor C04701, there is often liquid carry - over in the suction buffer tank. When the process load changes, liquid carry - over occurs. With the increase in load and the increase in inlet suction flow, the liquid propylene in the propylene deep - cooler of the low - temperature methanol washing is not completely vaporized. On the other hand, among the five propylene deep - coolers in the low - temperature methanol washing, three of them are installed at a position higher than the suction buffer tank of the screw - type propylene compressor C04701, and the gas - propylene pipeline is not designed with an upward slope, and the pipeline is relatively long, which is easy to form a liquid pocket, resulting in frequent liquid carry - over in the suction buffer tank, which is not conducive to the safe, stable, and long - term operation of the unit. Therefore, we need to propose a method for reducing liquid carry - over at the inlet of the screw - type propylene compressor to solve the above - mentioned problems, making the suction buffer tank have a heating function, so that the liquid propylene brought into the buffer tank is heated and evaporated into gaseous propylene through the heat - exchange tubes, reducing the occurrence of liquid carry - over and improving the safety and stability of the unit operation. Summary of the Invention

[0004] The object of the present invention is to provide a method for reducing liquid carry - over at the inlet of a screw - type propylene compressor, with a suction buffer tank having a heating function, so that the liquid propylene brought into the buffer tank is heated and evaporated into gaseous propylene through a heat - exchange tube, reducing the occurrence of liquid carry - over and improving the safety and stability of the unit operation, in order to solve the problems raised in the above - mentioned background technology.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A method for reducing liquid carry - over at the inlet of a screw - type propylene compressor includes the following steps:

[0007] S1. Add a three - way valve to the pipeline connecting the propylene flash tank and the propylene sub - cooler, connect the other end of the three - way valve to the lower part of the suction buffer tank of the compressor inlet, and connect the upper end of the suction buffer tank to the propylene compressor.

[0008] S2. Add a floating - head U - shaped heat - exchange tube bundle and a partitioned head at the bottom of the suction buffer tank, connect the inlet end of the floating - head U - shaped heat - exchange tube bundle to liquid propylene, and connect the other side of the floating - head U - shaped heat - exchange tube bundle to the main pipeline after the three - way valve, and then enter the propylene sub - cooler after convergence.

[0009] S3. The gaseous propylene from the methanol washing section enters the propylene compressor for compression after gas - liquid separation in the suction buffer tank, generating gaseous propylene.

[0010] S4. After the gaseous propylene is condensed by the propylene condenser, the condensed liquid enters the propylene receiving tank, and the un - condensed gas enters the inert gas cooler.

[0011] S5. The liquid in the propylene receiving tank is depressurized through a throttle valve and then enters the propylene flash tank. The gas after flashing returns to the second - stage gas - adding section of the propylene compressor. Part of the liquid after flashing enters the suction buffer tank for heat exchange through the three - way valve, and then the liquid after heat exchange converges with the main path of the three - way valve and enters the propylene sub - cooler. Another part of the liquid after flashing enters the propylene sub - cooler for flashing and temperature reduction, and the gaseous propylene obtained after flashing and temperature reduction enters the suction buffer tank.

[0012] Preferably, spiral guide vanes are arranged at the inlet of the suction buffer tank, a wire - mesh demisting layer is arranged at the top of the suction buffer tank, a liquid level gauge and an automatic drain valve are arranged at the bottom of the suction buffer tank, and the gas phase temperature after gas - liquid separation in the suction buffer tank is - 43°C to - 46.42°C.

[0013] Preferably, two propylene compressors are provided, the two propylene compressors are arranged in parallel, and the upper ends of the suction buffer tank are connected to both propylene compressors, and the inlet ends of the propylene sub - cooler are connected to the outlet ends of both propylene compressors.

[0014] Preferably, the pipeline connecting the suction buffer tank to the propylene compressor is connected to the inert gas cooler. The inert gas cooler further cools the propylene in the non-condensable gas. The liquefied propylene cooled down returns to the propylene receiving tank, and the non-condensable gas that has not been condensed is discharged to the propylene flare. An inert gas vent valve is installed on the pipeline connecting the inert gas cooler to the propylene flare.

[0015] Preferably, the propylene compressor is a two-stage compressor. After two-stage compression, the propylene compressor produces gaseous propylene with a pressure of 1.72 MPaG - 1.74 MPaG and a temperature of 82.7 °C - 93.15 °C.

[0016] Preferably, the throttle valve is located on the pipeline connecting the propylene receiving tank and the propylene flash tank. The inlet end of the throttle valve is connected to the inlet of the inert gas cooler through a shell-side liquid level control valve, and the outlet end of the throttle valve is connected to the liquid outlet end of the inert gas cooler through a tube-side regulating valve.

[0017] Preferably, a cooling water supply pipe and a cooling water return pipe are connected to the propylene condenser. Water valves are installed on both the cooling water supply pipe and the cooling water return pipe. The gas outlet end of the propylene condenser is connected to the gas inlet end of the inert gas cooler.

[0018] Preferably, the pressure for condensation in the propylene condenser is 1.59 MPaG - 1.66 MPaG, and the temperature is 40 °C - 42 °C.

[0019] Preferably, the liquefied propylene in the propylene receiving tank enters the propylene flash tank after the pressure is reduced by the throttle valve to 0.5 MPaG - 0.6 MPaG. The gaseous propylene flashed out from the propylene flash tank with a temperature of 0.8 °C - 1.21 °C returns to the second-stage gas addition section of the propylene compressor.

[0020] Preferably, a part of the liquefied propylene in the propylene flash tank with a temperature of 0.8 °C - 1 °C bypasses through a three-way valve and enters the U-shaped heat exchange tube of the suction buffer tank to exchange heat with the liquefied propylene in the tank. After heat exchange, it converges with the main path of the three-way valve and enters the tube side of the propylene subcooler, where the temperature is reduced to -10 °C to -11 °C, and the pressure is 0.49 MPaG - 0.5 MPaG. It enters the acid gas removal unit in the propylene subcooler as a refrigerant for user use. The gaseous propylene coming out of the deep cooler of the acid gas removal unit after absorbing heat then enters the refrigeration unit for circulation.

[0021] A method for reducing liquid carry-over at the inlet of a screw-type propylene compressor proposed by the present invention has the following advantages compared with the prior art:

[0022] 1. The present invention adds a three-way valve to the pipeline from the propylene flash tank to the propylene subcooler, leading out a liquid propylene pipeline to the lower part of the suction buffer tank at the compressor inlet. A floating head type U-shaped heat exchange tube bundle and a partitioned head are added at the bottom. The liquid propylene is connected to one side of the inlet, and the liquid propylene enters the U-shaped heat exchange tube bundle to exchange heat with the propylene liquid carried at the bottom of the suction buffer tank. The liquid propylene in this liquid-carrying part is heated into gaseous propylene and enters the compressor inlet, reducing the occurrence of liquid-carrying and improving the safety and stability of the unit operation.

[0023] 2. The liquid propylene after heat exchange in the present invention is led out from the other side at the bottom of the suction buffer tank, connected and merged with the main pipeline after the three-way valve, and then enters the propylene subcooler. Through the outlet temperature value of the U-shaped heat exchange tube of the suction buffer tank, the three-way valve adjusts the liquid propylene flow rate in the U-shaped heat exchange tube to achieve automatic temperature adjustment, without consuming additional steam for heating, and using the heat exchange of propylene itself to achieve energy conservation and consumption reduction. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is the flow chart of the present invention;

[0025] Figure 2 is the schematic diagram of the principle of the present invention;

[0026] Figure 3 is the schematic structural diagram of the suction buffer tank of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. The specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0028] The present invention provides a method for reducing liquid carry-over at the inlet of a screw propylene compressor as shown in Figures 1-3 and includes the following steps:

[0029] S1. Add a three-way valve to the pipeline connecting the propylene flash tank and the propylene subcooler, connect the other end of the three-way valve to the lower part of the suction buffer tank at the compressor inlet, and connect the upper end of the suction buffer tank to the propylene compressor;

[0030] At the inlet of the suction buffer tank, spiral guide vanes are provided. A swirling flow is formed through the spiral guide vanes, similar to cyclone separation, enhancing the centrifugal separation effect. A wire mesh demisting layer is provided at the top of the suction buffer tank to capture liquid droplets with a particle size less than 10 μm. A liquid level gauge and an automatic drain valve are provided at the bottom of the suction buffer tank. The liquid accumulation is monitored and drained in real time through the liquid level gauge and the automatic drain valve to prevent liquid carry - over of gas caused by too high liquid level. The drainage frequency is dynamically adjusted according to the propylene dew point temperature and the load of the propylene compressor. The gas phase temperature after gas - liquid separation in the suction buffer tank is - 43°C to - 46.42°C.

[0031] Two propylene compressors are provided, and the two propylene compressors are arranged in parallel. One propylene compressor is a motor - driven normal - use machine (such as Figure 2 C04701 in [reference]), and the other propylene compressor is a standby machine for the centrifugal propylene compressor C04701 (such as Figure 2 C04301 in [reference]). The upper ends of the suction buffer tank are connected to the two propylene compressors. The inlet ends of the propylene sub - cooler are connected to the outlet ends of the two propylene compressors. The propylene compressor is a two - stage compression, and the propylene compressor produces gaseous propylene with a pressure of 1.72 MPaG - 1.74 MPaG and a temperature of 82.7°C - 93.15°C after two - stage compression.

[0032] As Figure 2 shown, the pipeline connecting the suction buffer tank and the propylene compressor is connected to the inert gas cooler. The inert gas cooler further cools the propylene in the non - condensable gas. The liquefied propylene cooled down returns to the propylene receiving tank, and the non - condensable gas that has not been condensed is discharged to the propylene flare. And an inert gas vent valve PV - 04308 is installed on the pipeline connecting the inert gas cooler and the propylene flare, which is used for venting the inert gas condensed in the tube side of the inert gas cooler E04305 to the flare through this valve in the equipment tube side.

[0033] S2. Add a floating - head U - type heat - exchange tube bundle and a partitioned head at the bottom of the suction buffer tank. As Figure 3 shown, connect the inlet end of the floating - head U - type heat - exchange tube bundle to the liquid propylene. The other side of the floating - head U - type heat - exchange tube bundle is connected to the main pipeline after the three - way valve and then converges and enters the propylene sub - cooler. The outlet end of the three - way valve TV04701 is connected to the propylene sub - cooler through the propylene sub - cooler liquid level control valve LV - 04306. The liquid propylene passing through this propylene sub - cooler liquid level control valve LV - 04306 evaporates and absorbs heat in the shell side of the propylene sub - cooler E04302 and becomes gaseous propylene and goes into the compressor inlet suction buffer tank V04701;

[0034] S3. The gaseous propylene in the methanol washing section enters the propylene compressor for compression after gas - liquid separation in the suction buffer tank, generating gaseous propylene;

[0035] S4. After the gaseous propylene is condensed by the propylene condenser, the condensed liquid enters the propylene receiver tank, and the uncondensed gas enters the inert gas cooler;

[0036] A cooling water supply pipe and a cooling water return pipe are connected to the propylene condenser. Water valves are installed on both the cooling water supply pipe and the cooling water return pipe. The gas outlet end of the propylene condenser is connected to the gas inlet end of the inert gas cooler; the pressure for condensation of the propylene condenser is 1.59 MPaG - 1.66 MPaG, and the temperature is 40°C - 42°C.

[0037] The liquid propylene in the propylene receiver tank enters the propylene flash tank after being depressurized by a throttle valve at a pressure of 0.5 MPaG - 0.6 MPaG. The gaseous propylene flashed from the propylene flash tank at a temperature of 0.8°C - 1.21°C returns to the second-stage gas addition section of the propylene compressor.

[0038] S5. The liquid in the propylene receiver tank is depressurized by a throttle valve and then enters the propylene flash tank. The flashed gas returns to the second-stage gas addition section of the propylene compressor. Part of the flashed liquid enters the suction buffer tank through a three-way valve for heat exchange, and then the liquid after heat exchange converges with the main path of the three-way valve and enters the propylene subcooler. Another part of the flashed liquid enters the propylene subcooler for flash cooling, and the gaseous propylene obtained from the flash cooling enters the suction buffer tank.

[0039] The throttle valve is located on the connecting pipeline between the propylene receiver tank and the propylene flash tank. The inlet end of the throttle valve is connected to the inlet of the inert gas cooler E-04305 through the shell-side liquid level control valve LV-04308. The liquid propylene passing through this shell-side liquid level control valve LV-04308 evaporates and absorbs heat in the shell side of the inert gas cooler E-04305 and becomes gaseous propylene to enter the suction buffer tank V04701 at the compressor inlet. The outlet end of the throttle valve is connected to the liquid outlet end of the inert gas cooler E-04305 through the tube-side regulating valve LV-04310. The liquid propylene cooled by the liquid propylene passing through the shell-side liquid level control valve LV-04308 in the tube side of the inert gas cooler E-04305 (heat exchange between the tube and shell sides of the inert gas cooler E-04305 equipment) returns to the propylene flash tank V-04302 through the tube-side regulating valve LV-04310 valve.

[0040] Part of the liquid propylene in the propylene flash tank at a temperature of 0.8°C - 1°C enters the U-shaped heat exchange tube of the suction buffer tank through the bypass of the three-way valve to exchange heat with the liquid propylene in the tank. After heat exchange, it converges with the main path of the three-way valve and enters the tube side of the propylene subcooler, where the temperature drops to -10°C to -11°C and the pressure is 0.49 MPaG - 0.5 MPaG. It enters the acid gas removal unit in the propylene subcooler as a refrigerant for user use. The gaseous propylene coming out of the deep cooler of the acid gas removal unit and absorbing heat then enters the refrigeration unit for circulation.

[0041] During operation, as Figure 2 shown, the gaseous propylene from the low-temperature methanol washing section passes through the inlet suction buffer tank V04701. After gas-liquid separation, the gaseous phase temperature is -43°C to -46.42°C and enters the propylene compressor C04701. After two-stage compression, the produced gaseous propylene has a pressure of 1.72 MPaG - 1.74 MPaG and a temperature of 82.7°C - 93.15°C. The gaseous propylene passes through the propylene condenser E04301 for condensation. The condensed liquid propylene has a pressure of 1.59 MPaG - 1.66 MPaG and a temperature of 40°C - 42°C and enters the propylene receiving tank V04301. The uncondensed gas is mixed with the non-condensable gas in the propylene receiving tank V04301 and then enters the inert gas cooler E04305.

[0042] The liquid propylene in the propylene receiving tank V04301 passes through the throttle valve LV04304 to reduce the pressure to 0.5 MPaG - 0.6 MPaG and enters the propylene flash tank V04302. The flashed gaseous propylene has a temperature of 0.8°C - 1.21°C and returns to the second-stage gas addition section of the propylene compressor C04701. The liquid propylene in the propylene flash tank V04302 is divided into two parts. One part of the liquid propylene has a temperature of 0.8°C - 1°C and bypasses through the three-way valve TV04701 to enter the U-shaped heat exchange tube of the suction buffer tank V04701 to exchange heat with the liquid propylene in the tank. After heat exchange, it converges with the main path of the three-way valve TV04701 and enters the tube side of the propylene sub-cooler E04302, where the temperature drops to -10°C to -11°C and the pressure is 0.49 MPaG - 0.5 MPaG. It enters the acid gas removal unit as a refrigerant for user use. The gaseous propylene that absorbs heat from the cryogenic cooler in the acid gas removal unit then enters the refrigeration unit for circulation. The other part of the liquid propylene enters the shell side of the propylene sub-cooler E04302 for flashing to cool the liquid propylene in the tube side. The gaseous propylene after flashing of the liquid propylene in the shell side enters the suction buffer tank V04701.

[0043] The non-condensable gas mixed in the propylene condenser E04301 and the propylene receiving tank V04301 enters the tube side of the inert gas cooler E04305 and is cooled to -35°C to -37°C by the evaporation of the liquid propylene from the propylene receiving tank, further cooling the propylene in the non-condensable gas. The cooled liquid propylene returns to the propylene receiving tank, and the uncondensed non-condensable gas is discharged to the propylene torch.

[0044] In summary, by adding a three-way valve TV04701 to the pipeline from the propylene flash tank V04302 to the propylene subcooler E04302, a liquid propylene pipeline is led to the lower part of the suction buffer tank V04701 at the compressor inlet. A floating head U-shaped heat exchange tube bundle and a partitioned head are added at the bottom. The liquid propylene at 1°C enters the U-shaped heat exchange tube bundle and exchanges heat with the propylene liquid at -43°C at the bottom of the suction buffer tank V04701. The liquid propylene in this liquid-carrying part is heated to gaseous propylene and enters the inlet of the propylene compressor C04701, reducing the occurrence of liquid-carrying situations and improving the safety and stability of the unit operation. The heat-exchanged liquid propylene is led out from the other side at the bottom of the suction buffer tank V04701, connected to the main pipeline after the three-way valve TV04701, and then enters the propylene subcooler E04302. Through the outlet temperature value of the U-shaped heat exchange tube of the suction buffer tank V04701, the three-way valve TV04701 adjusts the liquid propylene flow rate in the U-shaped heat exchange tube to achieve automatic temperature adjustment, without consuming additional steam for heating. By using the heat exchange of propylene itself, energy conservation and consumption reduction are achieved, and the startup times of the propylene condensate pump can also be reduced, reducing the occurrence of pump cavitation leakage.

[0045] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for reducing liquid carryover at the inlet of a screw propylene compressor, characterized in that: The steps include: S1. Add a three-way valve on the pipeline connecting the propylene flash tank to the propylene supercooler, connect the other end of the three-way valve to the lower part of the suction buffer tank at the compressor inlet, and connect the upper end of the suction buffer tank to the propylene compressor; S2. Add a floating head U-shaped heat exchange tube bundle and a baffled head at the bottom of the suction buffer tank, connect the inlet end of the floating head U-shaped heat exchange tube bundle to liquid propylene, and connect the other side of the floating head U-shaped heat exchange tube bundle to the main line behind the three-way valve and then enter the propylene subcooler; S3, the gaseous propylene in the methanol washing section enters the propylene compressor for compression after gas-liquid separation in the suction buffer tank to produce gaseous propylene; S4, after the gaseous propylene is condensed in the propylene condenser, the condensed liquid enters the propylene receiving tank, and the uncondensed gas enters the inert gas cooler; S5. The liquid in the propylene receiving tank is depressurized by a throttle valve and then enters a propylene flash tank. After flashing, the gas returns to the second-stage gasification section of the propylene compressor. A part of the liquid after flashing enters the suction buffer tank through a three-way valve for heat exchange. The liquid after heat exchange is combined with the main line of the three-way valve and then enters the propylene supercooler. Another part of the liquid after flashing enters the propylene supercooler for flash cooling. The gaseous propylene obtained by flash cooling enters the suction buffer tank.

2. A method for reducing liquid carryover at the inlet of a screw propylene compressor according to claim 1, characterized in that: A spiral guide plate is provided at the inlet of the air intake buffer tank, a wire mesh defoaming layer is provided on the top of the air intake buffer tank, a liquid level gauge and an automatic drain valve are provided at the bottom of the air intake buffer tank, and the gas phase temperature after gas-liquid separation in the air intake buffer tank is -43°C to -46.42°C.

3. The method for reducing liquid carryover at the inlet of a screw propylene compressor according to claim 1, characterized in that: The propylene compressors are provided in two sets, the two propylene compressors are arranged in parallel, and the upper ends of the air intake buffer tanks are connected to the two propylene compressors, and the inlet ends of the propylene supercoolers are connected to the outlet ends of the two propylene compressors.

4. A method for reducing liquid carryover at the inlet of a screw propylene compressor according to claim 3, characterized in that: The pipeline connecting the air intake buffer tank and the propylene compressor is connected to the inert gas cooler, and the inert gas cooler further cools the propylene in the non-condensable gas. The cooled liquid propylene returns to the propylene receiving tank, and the uncondensed non-condensable gas is discharged to the propylene flare. An inert gas vent valve is installed on the pipeline connecting the inert gas cooler and the propylene flare.

5. A method for reducing liquid carryover at the inlet of a screw propylene compressor according to claim 4, characterized in that: The propylene compressor is a two-stage compression compressor, and the propylene compressor outputs gaseous propylene with a pressure of 1.72MPaG-1.74MPaG and a temperature of 82.7°C-93.15°C through two-stage compression.

6. The method for reducing liquid carryover at the inlet of a screw propylene compressor according to claim 1, characterized in that: The throttle valve is located on the connecting pipeline between the propylene receiving tank and the propylene flash tank, the inlet end of the throttle valve is connected to the inlet of the inert gas cooler through the shell side liquid level control valve, and the outlet end of the throttle valve is connected to the liquid outlet end of the inert gas cooler through the tube side regulating valve.

7. The method for reducing liquid carryover at the inlet of a screw propylene compressor according to claim 1, characterized in that: The propylene condenser is connected with a cooling water supply pipe and a cooling water return pipe, and water valves are installed on the cooling water supply pipe and the cooling water return pipe. The air outlet end of the propylene condenser is connected with the air inlet end of the inert gas cooler.

8. A method for reducing liquid carryover at the inlet of a screw propylene compressor according to claim 7, characterized in that: The propylene condenser performs condensation at a pressure of 1.59 MPaG-1.66 MPaG and a temperature of 40°C-42°C.

9. A method for reducing liquid carryover at the inlet of a screw propylene compressor according to claim 8, characterized in that: The liquid propylene in the propylene receiving tank is depressurized by a throttle valve to a pressure of 0.5MPaG-0.6MPaG and enters the propylene flash tank. The gas propylene flashed out of the propylene flash tank has a temperature of 0.8°C-1.21°C and returns to the second gasification section of the propylene compressor.

10. A method for reducing liquid carryover at the inlet of a screw propylene compressor according to claim 9, characterized in that: A portion of the liquid propylene in the propylene flash tank has a temperature of 0.8°C-1°C and enters the U-shaped heat exchange tube of the suction buffer tank through a three-way valve bypass to exchange heat with the liquid propylene in the tank. After the heat exchange, it merges with the main path of the three-way valve and enters the propylene supercooler. The temperature is reduced to -10°C to -11°C and the pressure is 0.49MPaG-0.5MPaG. It enters the acid gas removal unit in the propylene supercooler as a refrigerant for user use. The gaseous propylene that absorbs heat from the deep freezer of the acid gas removal unit enters the refrigeration unit for circulation.

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