Screw steam compression system

Abstract

The present invention discloses a screw type water vapor compression system, comprising a liquid spraying twin-screw compressor, a driving motor, a gas-liquid separator, a water vapor inlet pipeline, a liquid replenishing pipeline, an exhaust pipeline and a circulating liquid spraying pipeline. The driving motor is connected to the male rotor of the compressor. The air intake of the liquid spraying twin-screw compressor is connected to the water vapor inlet pipeline, the exhaust port is connected to the air intake of the gas-liquid separator through the exhaust pipeline, the liquid replenishing port is connected to the liquid replenishing pipeline, and a flow control valve is arranged on the liquid replenishing pipeline. The liquid outlet of the gas-liquid separator is connected to the circulating liquid spraying port of the liquid spraying twin-screw compressor through the circulating liquid spraying pipeline, the gas-liquid separator is provided with a liquid level transmitter for measuring the liquid level of the separated liquid, and the first control output end of the liquid level transmitter is electrically connected to the control input end of the flow control valve. The present invention can compress water vapor with a higher pressure ratio, and the compression process can be cooled by liquid spraying, and the compression efficiency is high.

Description

Technical Field

[0001] The present invention relates to a compression system for compressing water vapor. Background Art

[0002] Existing water vapor compressors are mainly centrifugal and Roots types, which have many restrictions on gas and the compressor pressure ratio is limited, usually limited to about 2.5. In addition, existing water vapor compressors generally do not allow the intake air to carry liquid, and the efficiency of dry compression is low. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a screw type water vapor compression system which can compress water vapor with a higher pressure ratio, can spray liquid for cooling during the compression process and has high compression efficiency.

[0004] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0005] The screw water vapor compression system comprises a liquid injection twin-screw compressor, a driving motor, a gas-liquid separator, a water vapor inlet pipeline, a liquid replenishing pipeline, an exhaust pipeline and a circulating liquid injection pipeline; the liquid injection twin-screw compressor comprises a compressor housing, a female rotor and a male rotor; the female rotor and the male rotor are rotatably arranged on the compressor housing and mesh with each other; the driving motor is connected to the male rotor to drive the male rotor to rotate; the liquid injection twin-screw compressor is provided with an air intake port, an exhaust port, a liquid replenishing port and a circulating liquid injection port; the air intake port of the liquid injection twin-screw compressor is connected to the water vapor inlet pipeline, and the exhaust port of the liquid injection twin-screw compressor is connected to the water vapor inlet pipeline. The exhaust pipeline is connected to the air inlet of the gas-liquid separator, the liquid replenishing port of the liquid-spraying twin-screw compressor is connected to the liquid replenishing pipeline, and a flow control valve is provided on the liquid replenishing pipeline; the liquid outlet of the gas-liquid separator is connected to the circulating liquid spraying port of the liquid-spraying twin-screw compressor through the circulating liquid spraying pipeline, and the gas-liquid separator is provided with a liquid level transmitter for measuring the liquid level of the separated liquid, and the first control output end of the liquid level transmitter is electrically connected to the control input end of the flow control valve, and the liquid level transmitter is used to control the flow control valve on the liquid replenishing pipeline to open when the measured liquid level of the separated liquid does not reach the preset first liquid level, so as to achieve liquid replenishment.

[0006] Since the present invention adopts the above technical solution, the technical effect produced is obvious:

[0007] 1. The screw-type water vapor compression system according to an embodiment of the present invention uses a liquid-spraying twin-screw compressor, the single-machine pressure ratio can be up to 10, the internal pressure ratio is fixed, the water vapor compression process is wet compression, and a certain amount of liquid is sprayed to cool the compression process, so that the compression process is closer to an isothermal process, thereby improving the compression efficiency;

[0008] 2. The screw-type water vapor compression system according to an embodiment of the present invention is provided with a liquid replenishment system to ensure that the compressor can operate continuously, reliably and efficiently; and because of the use of circulating liquid injection and air suction liquid replenishment, a double insurance of liquid injection cooling is achieved, thereby ensuring that the exhaust temperature of the compressor is not too high;

[0009] 3. The screw-type water vapor compression system according to an embodiment of the present invention realizes automatic control of the working process: automatically adjusts the injection amount and the liquid replenishment amount to control the exhaust temperature, automatically starts the exhaust venting to control the exhaust pressure, and automatically adjusts the speed to adapt to the changes in the suction and exhaust pressure and flow rate;

[0010] 4. The liquid injection twin-screw compressor used in the screw-type water vapor compression system according to one embodiment of the present invention has no regulating mechanisms such as air valves and sliding valves, no wearing parts, a long service life, and a maximum continuous operation cycle of more than 24,000 hours. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 An overall schematic diagram of a screw type water vapor compression system according to an embodiment of the present invention is shown.

[0012] Figure 2 A schematic diagram of a female rotor and a male rotor according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0013] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0014] Figure 1 FIG. 1 is a schematic diagram of a screw type water vapor compression system according to an embodiment of the present invention. Figure 1 According to an embodiment of the present invention, a screw water vapor compression system includes a liquid injection twin-screw compressor 1, a drive motor 2, a gas-liquid separator 3, a water vapor inlet pipeline 41, a liquid replenishment pipeline 42, an exhaust pipeline 43, a circulating liquid injection pipeline 44, a frequency converter 5 and a controller 6.

[0015] The liquid injection twin-screw compressor 1 comprises a compressor housing 10, a female rotor 11 and a male rotor 12. The female rotor 11 and the male rotor 12 are rotatably arranged on the compressor housing 10 and mesh with each other. The driving motor 2 is connected to the male rotor 12 to drive the male rotor 12 to rotate. The liquid injection twin-screw compressor 1 is provided with an air intake port, an air exhaust port, a liquid replenishing port and a circulating liquid injection port. The air intake port of the liquid injection twin-screw compressor 1 is connected to the water vapor inlet pipeline 41, the air exhaust port of the liquid injection twin-screw compressor 1 is connected to the air inlet of the gas-liquid separator 3 through the air exhaust pipeline 43, the liquid replenishing port of the liquid injection twin-screw compressor 1 is connected to the liquid replenishing pipeline 42, and the liquid replenishing pipeline 42 is provided with a flow control valve 91.

[0016] exist Figure 1In the example, the screw water vapor compression system is provided with an air intake nipple 7, one end of the air intake nipple 7 is connected to the air intake port of the liquid injection twin-screw compressor, and the other end of the air intake nipple 7 is connected to the water vapor inlet pipeline 41; the above-mentioned liquid replenishment port and circulating liquid injection port are respectively arranged on the air intake nipple 7. In other embodiments, the liquid replenishment port and the circulating liquid injection port can also be arranged on the compression section of the compressor housing 10, in which case the liquid can be sprayed into the compression chamber of the compressor. The liquid sprayed into the compressor can cool the compression process, making the compression process closer to an isothermal process, thereby improving the compression efficiency; the liquid is not limited to water, but can also be diesel, etc.

[0017] Furthermore, the metal parts of the liquid injection twin-screw compressor 1 that are in contact with water and water vapor are made of stainless steel. The liquid injection twin-screw compressor 1 allows the suction to carry liquid, tiny particles, etc., and the entire system can operate stably without corrosion or wear.

[0018] The liquid outlet of the gas-liquid separator 3 is connected to the circulating liquid injection port of the liquid injection twin-screw compressor 1 through the circulating liquid injection pipeline 44, so as to circulate and spray the separated liquid into the suction position of the compressor. The gas-liquid separator 3 is provided with a liquid level transmitter 31 for measuring the liquid level of the separated liquid. The first control output end of the liquid level transmitter 31 is electrically connected to the control input end of the flow control valve 91. The liquid level transmitter 31 is used to control the flow control valve 91 on the liquid replenishment pipeline 42 to open when the measured liquid level of the separated liquid does not reach the preset first liquid level to achieve liquid replenishment, and to control the flow control valve 91 to close when the measured liquid level of the separated liquid reaches the preset first liquid level. The liquid replenishment pipeline 42 can deal with the situation of insufficient circulating liquid injection caused by insufficient liquid injection or poor gas-liquid separation effect, or the situation of no circulating liquid injection when the machine is just started.

[0019] Furthermore, the bottom of the gas-liquid separator 3 is connected to a drain pipe 32, and a drain valve 33 is provided on the drain pipe 32. The second control output end of the liquid level transmitter 31 is electrically connected to the control input end of the drain valve 33, and the liquid level transmitter 31 is used to control the drain valve 33 to open when the measured liquid level of the separated liquid reaches a preset second liquid level, so as to drain the excess accumulated liquid. The second liquid level is higher than the first liquid level.

[0020] Furthermore, the top of the gas-liquid separator 3 is connected to the steam outlet pipeline 34 and the vent pipeline 35 respectively, the vent pipeline 35 is connected to the atmosphere, and a pressure relief vent valve 36 is provided on the vent pipeline 35. A pressure transmitter 92 is provided on the exhaust pipeline 43, and the pressure transmitter 92 is used to measure the exhaust pressure of the liquid injection twin-screw compressor 1. The control output end of the pressure transmitter 92 is electrically connected to the control input end of the pressure relief vent valve 36. The pressure transmitter 92 is used to control the pressure relief vent valve 36 to open when the measured exhaust pressure reaches a preset exhaust pressure threshold, so that the exhaust pressure can be quickly unloaded to protect the compressor from running smoothly. In addition, when the content of air and other gases in the water vapor is high, the water vapor can also be purified by opening the pressure relief vent valve.

[0021] Furthermore, the water vapor inlet pipeline 41 is provided with an air intake shut-off valve 93 , and the steam outlet pipeline 34 is provided with an exhaust shut-off valve 94 .

[0022] The power output end of the frequency converter 5 is electrically connected to the power input end of the drive motor 2, and the output shaft of the drive motor 2 is connected to the male rotor 12 through a speed-increasing gearbox. The present invention uses a speed-increasing gear plus a frequency-inverting motor to control the compressor displacement, which can achieve speed regulation as low as 600rpm and up to 9000rpm, can adjust the load in a large range, and can adapt to fluctuations in working conditions, while helping to avoid the resonant frequency of the compressor unit. In other embodiments, a liquid-gas coupler, a magnetic coupler, a clutch, etc. can also be used instead of a speed-increasing gearbox for speed regulation.

[0023] The signal output end of the pressure transmitter 92 is electrically connected to the signal input end of the controller 6, and the controller 6 is communicatively connected to the frequency converter 5. The controller 6 can control the frequency converter 5 to adjust the speed of the compressor to adapt to the changes in the suction and exhaust pressure and flow rate according to the exhaust pressure value detected by the pressure transmitter 92. The controller 6 can be a PLC controller.

[0024] Please refer to Figure 2 Both ends of the female rotor 11 and the male rotor 12 are provided with shaft seals, respectively. Each shaft seal includes a front seal 13 close to the compression chamber of the liquid injection twin-screw compressor and a main seal 14 away from the compression chamber of the liquid injection twin-screw compressor. Preferably, the front seal 13 is a labyrinth seal and the main seal 14 is a dry gas seal. The dry gas seal can ensure that the working gas inside the compressor is isolated from the external environment.

[0025] The dry gas seal can use nitrogen, water vapor and other gases. In this embodiment, the dry gas seal uses compressed air that is easily available in the factory. The screw type water vapor compression system includes a compressed air inlet pipeline 45, which is respectively connected to the water vapor inlet pipeline 41, the dry gas seals at both ends of the male rotor and the dry gas seals at both ends of the female rotor. At this time, in addition to being used as sealing gas, the compressed air is also used as pipeline purge gas and valve start control gas.

[0026] The screw-type water vapor compression system according to an embodiment of the present invention can be used in the water vapor supercharging process, that is, to pressurize low-pressure gaseous water vapor through electric power to obtain high-pressure water vapor. Specific application fields include but are not limited to the following industrial sites: water vapor supercharging and transportation, water vapor closed-cycle heat pump system, MVR (mechanical vapor recompression) technology and the application of this technology in seawater desalination, sewage treatment, chemical distillation, waste heat utilization and other fields.

[0027] The above description is a further explanation of the present invention in combination with specific implementation methods and drawings. However, the present invention can obviously be implemented in a variety of other methods different from the description, and those skilled in the art can generalize and deduce according to actual usage without violating the content of the present invention. Therefore, the content of the above specific embodiments should not limit the protection scope determined by the present invention.

Claims

1. A screw type water vapor compression system, characterized in that: It includes a liquid injection twin-screw compressor, a driving motor, a gas-liquid separator, a water vapor inlet pipeline, a liquid replenishment pipeline, an exhaust pipeline, a circulating liquid injection pipeline and a compressed air inlet pipeline; The liquid-spraying twin-screw compressor comprises a compressor housing, a female rotor and a male rotor; the female rotor and the male rotor are rotatably arranged on the compressor housing and mesh with each other; the driving motor is connected to the male rotor to drive the male rotor to rotate; the liquid-spraying twin-screw compressor is provided with an air intake port, an air exhaust port, a liquid replenishing port and a circulating liquid-spraying port; the air intake port of the liquid-spraying twin-screw compressor is connected with a water vapor inlet pipeline, the air exhaust port of the liquid-spraying twin-screw compressor is connected with an air inlet port of the gas-liquid separator through an air exhaust pipeline, the liquid replenishing port of the liquid-spraying twin-screw compressor is connected with the liquid replenishing pipeline, and a flow control valve is provided on the liquid replenishing pipeline; The liquid outlet of the gas-liquid separator is connected to the circulating liquid injection port of the liquid injection twin-screw compressor through the circulating liquid injection pipeline. The gas-liquid separator is provided with a liquid level transmitter for measuring the liquid level of the separated liquid. The first control output end of the liquid level transmitter is electrically connected to the control input end of the flow control valve. The liquid level transmitter is used to control the flow control valve on the liquid replenishment pipeline to open when the measured liquid level of the separated liquid does not reach the preset first liquid level, so as to achieve liquid replenishment; the top of the gas-liquid separator is respectively connected to the steam outlet pipeline and the vent pipeline, the vent pipeline is connected to the atmosphere, and a pressure relief vent valve is provided on the vent pipeline; a pressure transmitter is provided on the exhaust pipeline, and the pressure transmitter is used to measure the exhaust pressure of the liquid injection twin-screw compressor. The control output end of the pressure transmitter is electrically connected to the control input end of the pressure relief vent valve, and the pressure transmitter is used to control the pressure relief vent valve to open when the measured exhaust pressure reaches a preset exhaust pressure threshold; The compressed air inlet pipeline is in communication with the water vapor inlet pipeline.

2. The screw type water vapor compression system according to claim 1, characterized in that: The screw-type water vapor compression system includes an intake nipple, one end of which is connected to the intake port of the liquid injection twin-screw compressor, and the other end of which is connected to the water vapor inlet pipeline; the liquid replenishment port and the circulating liquid injection port are respectively arranged on the intake nipple.

3. The screw type water vapor compression system according to claim 1, characterized in that: The bottom of the gas-liquid separator is connected to a sewage pipeline, and a sewage valve is provided on the sewage pipeline; The second control output end of the liquid level transmitter is electrically connected to the control input end of the drain valve, and the liquid level transmitter is used to control the drain valve to open when the measured liquid level of the separated liquid reaches a preset second liquid level.

4. The screw type water vapor compression system according to claim 1, characterized in that: The screw type water vapor compression system comprises a controller, and the signal output end of the pressure transmitter is electrically connected to the signal input end of the controller.

5. The screw type water vapor compression system according to claim 4, characterized in that: The screw-type water vapor compression system comprises a frequency converter, a power output end of the frequency converter is electrically connected to a power input end of the drive motor, and the controller is communicatively connected to the frequency converter.

6. The screw type water vapor compression system according to claim 1, characterized in that: The metal parts of the liquid injection twin-screw compressor that are in contact with water and water vapor are made of stainless steel.

7. The screw type water vapor compression system according to claim 1, characterized in that: Both ends of the female rotor and both ends of the male rotor are respectively provided with shaft seals, and each of the shaft seals comprises a front seal close to the compression chamber of the liquid injection twin-screw compressor and a main seal away from the compression chamber of the liquid injection twin-screw compressor.

8. The screw type water vapor compression system according to claim 7, characterized in that: The front seal is a labyrinth seal; the main seal is a dry gas seal.

9. The screw type water vapor compression system according to claim 8, characterized in that: The compressed air inlet pipeline is respectively connected to the dry gas seals at both ends of the male rotor and the dry gas seals at both ends of the female rotor.

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