Gas compression separation residual pressure and waste heat recovery system of liquid injection screw compressor

Abstract

The utility model discloses a gas compression separation residual pressure and waste heat recovery system for a liquid injection screw compressor. The waste heat recovery system comprises a screw compressor, a motor, a clutch, a screw expander, a gas-liquid separator, a gas separation device, a first heat exchanger, a second heat exchanger, a cooler, a liquid injection regulating valve and a temperature transmitter. According to the gas compression separation residual pressure and waste heat recovery system of the liquid injection screw compressor, the energy recovery efficiency can be improved, the complexity of equipment is reduced, and product gas has a high enthalpy value.

Description

TECHNICAL FIELD

[0001] The utility model belongs to power machinery engineering technical field relates to a kind of excess pressure and waste heat recovery system, more particularly to a kind of gas compression separation excess pressure and waste heat recovery system of liquid injection screw compressor. BACKGROUND

[0002] Liquid injection double-screw compressor has the characteristics of rotary and volume, and a large amount of liquid needs to be injected during compression to reduce the temperature of the compression process, making the compression process closer to isothermal compression, thereby improving the compression efficiency. The temperature of the liquid is around 80°C, which is a low-grade heat source and is difficult to utilize effectively.

[0003] Some gas separation devices need to be implemented at high pressure and temperature, and the separated product gas does not require high pressure. The pressure energy cannot be effectively utilized by reducing the pressure through a pressure reducing valve. Alternatively, an expander connected to a generator is provided to recover the pressure energy. However, the temperature of the discharged gas is low, which is not conducive to subsequent utilization. The generator requires complex power distribution equipment and consumes a portion of the power itself.

[0004] Therefore, there is an urgent need to design a new excess pressure and waste heat recovery system to overcome at least some of the above-mentioned deficiencies of existing excess pressure and waste heat recovery systems. SUMMARY

[0005] The utility model provides a kind of gas compression separation excess pressure and waste heat recovery system of liquid injection screw compressor, can improve the efficiency of recovered energy, reduce the complexity of equipment, so that product gas has higher enthalpy.

[0006] To solve the above technical problems, according to one aspect of the utility model, the following technical solutions are adopted:

[0007] A gas compression separation excess pressure and waste heat recovery system of liquid injection screw compressor, the waste heat recovery system comprises: a screw compressor, a motor, a clutch, a screw expander, a gas-liquid separator, a gas separation device, a first heat exchanger, a second heat exchanger, and a cooler.

[0008] The motor includes a first output shaft and a second output shaft. The first output shaft of the motor is connected to the screw compressor and can drive the screw compressor to work. The second output shaft of the motor is connected to the screw expander through the clutch. The screw compressor is a liquid injection screw compressor.

[0009] The clutch can be automatically engaged when the rotational speed of the screw expander is higher than that of the motor. The clutch can be automatically disengaged when the rotational speed of the screw expander is lower than that of the motor.

[0010] The input end of the screw compressor is connected with a gas inlet, and the input end of the screw compressor is also connected with a liquid injection adjusting pipeline; a first end of the liquid injection adjusting pipeline is connected with an output end of a cooler, and a second end of the liquid injection adjusting pipeline sprays cooling liquid into the screw compressor;

[0011] The output end of the screw compressor is connected with a gas-liquid separator, and a gas-liquid mixture output by the screw compressor is subjected to gas-liquid separation through the gas-liquid separator; a first output end of the gas-liquid separator is connected with a first heat exchanger, and the first heat exchanger, a second heat exchanger and the cooler are sequentially connected; high-temperature and high-pressure liquid separated from the gas-liquid separator sequentially passes through the first heat exchanger, the second heat exchanger and the cooler, and is then sprayed into the liquid injection screw compressor to realize cyclic flow;

[0012] A second output end of the gas-liquid separator is connected with a gas separation device, mixed gas separated from the gas-liquid separator enters the gas separation device to be subjected to gas separation, heat is required to be dissipated to the outside during the separation process, the gas temperature is reduced, and tail gas separated out is output through a tail gas outlet;

[0013] A second output end of the gas separation device is connected with the first heat exchanger, high-temperature and high-pressure liquid separated from the gas-liquid separator is preheated through the first heat exchanger, product gas separated from the gas separation device is preheated, the product gas obtains a heat value from the first heat exchanger, the enthalpy value is increased, the recovery power of the screw expander is increased, the temperature of the gas discharged from the screw expander is increased, and the situation of low-temperature ice blocking is avoided.

[0014] As an embodiment of the utility model, the waste heat recovery system further includes a liquid injection adjusting valve and a temperature transmitter;

[0015] The liquid injection adjusting pipeline is provided with the liquid injection adjusting valve, and the opening degree of the liquid injection adjusting valve is controlled by the temperature transmitter arranged at the exhaust port of the compressor;

[0016] High-temperature and high-pressure liquid separated from the gas-liquid separator sequentially passes through the first heat exchanger, the second heat exchanger and the cooler, and is then sprayed into the liquid injection screw compressor to realize cyclic flow through the control of the liquid injection adjusting valve.

[0017] As an embodiment of the utility model, a check valve is arranged at the screw expander gas discharge pipeline to avoid backflow of gas in the shutdown condition, low-temperature gas discharged from the screw expander is subjected to heat exchange with the second heat exchanger to increase the temperature and increase the enthalpy value, and more suitable conditions are provided for subsequent gas utilization devices.

[0018] As an embodiment of the utility model, an air inlet adjusting valve is arranged at the inlet of the screw expander, the opening degree of the air inlet adjusting valve is controlled by the second pressure transmitter, and the pressure at the end of the gas utilization device is constant.

[0019] As an embodiment of the utility model, the pipeline is connected with the second heat exchanger gas outlet pipeline between the first heat exchanger and the gas adjusting valve, and the bypass adjusting valve is arranged, the opening of the bypass adjusting valve is controlled by the first pressure transmitter at the rear end of the gas separation device, and the working pressure of the gas separation device is constant.

[0020] As an embodiment of the utility model, in the state that the liquid level in the gas-liquid separator is reduced to the set low value, the liquid injection screw compressor is entered from the liquid inlet through the liquid supplement adjusting valve, and then the gas-liquid separator is entered, the opening of the liquid supplement adjusting valve is controlled by the liquid level variator.

[0021] As an embodiment of the utility model, in the state that the liquid level in the gas-liquid separator reaches the set high value, the liquid discharge adjusting valve is opened, the opening of the liquid discharge adjusting valve is controlled by the liquid level variator, the excess liquid is discharged to the liquid discharge outlet, and then the gas-liquid separator is constant.

[0022] As an embodiment of the utility model, the waste heat recovery system further comprises the gas utilization device.

[0023] As an embodiment of the utility model, the screw expander is a double-screw oil-free expander.

[0024] As an embodiment of the utility model, the clutch is a overrunning clutch.

[0025] As an embodiment of the utility model, the screw compressor is a liquid injection double-screw compressor.

[0026] The beneficial effects of the utility model are that the liquid injection screw compressor gas compression separation residual pressure waste heat recovery system can improve the efficiency of recovered energy, reduce the complexity of equipment, and make the product gas have a higher enthalpy value. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 It is the component schematic view of the gas compression separation residual pressure waste heat recovery system in an embodiment of the utility model. DETAILED DESCRIPTION

[0028] The preferred embodiments of the utility model are described in detail below with reference to the drawings.

[0029] In order to further understand the utility model, the preferred embodiments of the utility model are described below in combination with examples, but it should be understood that these descriptions are only for further illustrating the features and advantages of the utility model, and are not the limitation of the utility model claims.

[0030] The description of this part is only for several typical embodiments, and the utility model is not limited to the range of embodiment description. The same or similar prior art means and some technical features in the embodiment are replaced with each other, which is also within the description and protection range of the utility model.

[0031] The description of the steps in each embodiment in the specification is only for convenience, and the implementation mode of the application is not limited by the order of the steps.

[0032] The "connection" in the specification includes direct connection and indirect connection.

[0033] The utility model discloses a kind of liquid injection screw compressor gas compression separation residual pressure waste heat recovery system, Figure 1 It is the component schematic diagram of gas compression separation residual pressure waste heat recovery system in an embodiment of the utility model;Please refer to Figure 1 The waste heat recovery system includes: screw compressor 1, motor 2, clutch 3, screw expander 4, gas-liquid separator 5, gas separation device 6, first heat exchanger 7, second heat exchanger 8, cooler 9, liquid injection regulating valve 10 and temperature transmitter 16. Of course, liquid injection regulating valve 10 and temperature transmitter 16 can not be set.

[0034] The motor 2 includes first output shaft and second output shaft, and the first output shaft of motor 2 is connected to screw compressor 1, which can drive screw compressor 1 to work;The second output shaft of motor 2 is connected to screw expander 4 through clutch 3;The screw compressor 1 can be a liquid injection screw compressor, and the screw compressor 1 can be a double-screw oil-free expander.

[0035] In the state that the rotation speed of screw expander 1 is higher than that of motor 2, clutch 3 can be automatically put into use;In the state that the rotation speed of screw expander 1 is lower than that of motor 2, clutch 3 is automatically disconnected. The clutch 3 can be an overrunning clutch, and of course, other clutches can also be used.

[0036] The input end of the screw compressor 1 is connected to the gas inlet A, and the input end of the screw compressor 1 is also connected to the liquid injection regulating pipeline, which is provided with a liquid injection regulating valve 10. The first end of the liquid injection regulating pipeline is connected to the output end of the cooler 9, and the second end of the liquid injection regulating pipeline sprays cooling liquid into the screw compressor 1.

[0037] The output end of the screw compressor 1 is connected with a gas-liquid separator 5, and the gas-liquid mixture output by the screw compressor 1 is subjected to gas-liquid separation in the gas-liquid separator 5; the first output end of the gas-liquid separator 5 is connected with a first heat exchanger 7, and the first heat exchanger 7, a second heat exchanger 8 and a cooler 9 are connected in sequence; the high-temperature and high-pressure liquid separated from the gas-liquid separator 5 is sequentially subjected to the first heat exchanger 7, the second heat exchanger 8 and the cooler 9, and then is sprayed into the liquid-injection screw compressor 1 through a liquid-injection regulating valve 10 to realize a circulating flow; and the opening degree of the liquid-injection regulating valve 10 is controlled by a temperature transmitter 16 arranged at the exhaust port of the screw compressor 1.

[0038] The second output end of the gas-liquid separator 5 is connected with a gas separation device 6, and the mixed gas separated from the gas-liquid separator 5 enters the gas separation device 6 to be subjected to gas separation; the separation process needs to release heat to the outside, and the gas temperature is reduced; and the separated tail gas is output through a tail gas outlet B.

[0039] The second output end of the gas separation device 6 is connected with the first heat exchanger 7, and the high-temperature and high-pressure liquid separated from the gas-liquid separator 5 is subjected to preheating in the first heat exchanger 7 to preheat the product gas separated from the gas separation device 6; the product gas obtains heat value from the first heat exchanger 7, and the enthalpy value is increased, so that the recovery power of the screw expander is increased, the temperature of the exhaust gas of the screw expander 1 is increased, and the low-temperature ice blocking condition is avoided.

[0040] In an embodiment of the utility model, in an embodiment, the waste heat recovery system can further include an inlet regulating valve 11, a check valve 12, a gas utilization device 13, a bypass regulating valve 14, a liquid supplementing regulating valve 15, a liquid level transmitter 17, a first pressure transmitter 18, a second pressure transmitter 19 and a liquid discharging regulating valve 20.

[0041] The screw expander 1 is provided with the check valve 12, so that the gas backflow in the shutdown condition is avoided; the low-temperature gas discharged from the screw expander 4 is subjected to heat exchange with the second heat exchanger 8 to increase the temperature and increase the enthalpy value, so that more suitable conditions are provided for the subsequent gas utilization device.

[0042] The inlet of the screw expander is provided with the inlet regulating valve 11, the opening degree of the inlet regulating valve 11 is controlled by the second pressure transmitter 19, and the pressure at the end of the gas utilization device 13 is constant.

[0043] A pipeline is led out between the first heat exchanger 7 and the inlet regulating valve 11 and connected with the gas outlet pipeline of the second heat exchanger 8, and the bypass regulating valve 14 is arranged; the opening degree of the bypass regulating valve 14 is controlled by the first pressure transmitter 18 at the rear end of the gas separation device 6, and the working pressure of the gas separation device 6 is constant.

[0044] When the liquid level in the gas-liquid separator 5 is reduced to a set low value, the liquid enters the liquid injection screw compressor 1 from the liquid inlet C through the liquid supplementing regulating valve 15, and then enters the gas-liquid separator 5, and the opening degree of the liquid supplementing regulating valve 15 is controlled by the liquid level variator 17.

[0045] When the liquid level in the gas-liquid separator reaches a set high value, the liquid discharge regulating valve 20 is opened, the opening degree of the liquid discharge regulating valve 20 is controlled by the liquid level variator 17, and the excess liquid is discharged to the liquid discharge outlet, so that the gas-liquid separator is constant.

[0046] In addition, the excess pressure and waste heat recovery system can further comprise a main control module connected with the screw compressor 1, the motor 2, the screw expander 4, the gas-liquid separator 5, the gas separation device 6, the first heat exchanger 7, the second heat exchanger 8, the cooler 9, the liquid injection regulating valve 10, the temperature transmitter 16, the gas inlet regulating valve 11, the check valve 12, the gas utilization device 13, the bypass regulating valve 14, the liquid supplementing regulating valve 15, the liquid level transmitter 17, the first pressure transmitter 18, the second pressure transmitter 19 and the liquid discharge regulating valve 20.

[0047] The utility model further discloses a kind of excess pressure and waste heat recovery methods of the above-mentioned liquid injection screw compressor gas compression separation excess pressure and waste heat recovery system, and the excess pressure and waste heat recovery method comprises:

[0048] Mixed gas medium enters screw compressor from gas inlet, enters gas-liquid separator after screw compressor, and cooling liquid is sprayed by liquid injection regulating valve during compressor process;After gas-liquid mixture is separated by gas-liquid separator, high-temperature and high-pressure liquid sequentially passes through first heat exchanger, second heat exchanger, cooler, and then is sprayed into screw compressor by liquid injection regulating valve to realize circulating flow, and liquid injection regulating valve opening degree is controlled by compressor exhaust port temperature transmitter;

[0049] Mixed gas separated from gas-liquid separator enters gas separation device, and carries out gas separation, and needs to release heat to outside during separation process, and gas temperature reduces, and tail gas separated out passes through tail gas outlet;

[0050] High-temperature and high-pressure liquid separated by gas-liquid separator is preheated to product gas separated from gas separation device by first heat exchanger, and product gas obtains heat value from first heat exchanger, and enthalpy increases, and recovery power of screw expander is increased, and gas temperature discharged by screw expander is improved, to avoid low-temperature ice blocking situation.

[0051] In an embodiment of the utility model, the excess pressure and waste heat recovery method further comprises:

[0052] A check valve is arranged in the gas pipeline from the screw expander to avoid backflow of gas in the shutdown condition, and the low-temperature gas discharged from the screw expander exchanges heat with the second heat exchanger to increase the temperature and increase the enthalpy, so as to provide more suitable conditions for the subsequent gas utilization device.

[0053] An inlet gas regulating valve is arranged in the inlet of the screw expander, and the opening degree of the inlet gas regulating valve is controlled by a pressure transmitter to realize constant pressure at the gas utilization device end.

[0054] A pipeline is connected between the first heat exchanger and the inlet gas regulating valve and connected to the gas outlet pipeline of the second heat exchanger, and a bypass regulating valve is arranged, the opening degree of the bypass regulating valve is controlled by a pressure transmitter at the rear end of the gas separation device, and the working pressure of the gas separation device is constant.

[0055] When the liquid level in the gas-liquid separator is reduced to a low value, liquid is introduced into the liquid injection screw compressor through a liquid supplementing regulating valve and then into the gas-liquid separator, and the opening degree of the liquid supplementing regulating valve is controlled by a liquid level transmitter.

[0056] When the liquid level in the gas-liquid separator reaches a high value, a liquid discharging regulating valve is opened, the opening degree of the liquid discharging regulating valve is controlled by a liquid level transmitter, and the excess liquid is discharged to a liquid discharge outlet, thereby realizing constant gas-liquid separation.

[0057] In summary, the liquid injection screw compressor gas compression separation residual pressure and residual heat recovery system can improve the efficiency of energy recovery, reduce the complexity of the equipment, and make the product gas have a higher enthalpy.

[0058] It should be noted that the present application can be implemented in software and / or a combination of software and hardware; for example, it can be implemented by using an application specific integrated circuit (ASIC), a general purpose computer or any other similar hardware device. In some embodiments, the software program of the present application can be executed by a processor to realize the above steps or functions. Similarly, the software program of the present application (including related data structures) can be stored in a computer readable recording medium; for example, a RAM memory, a magnetic or optical drive or a soft disk and the like. In addition, some steps or functions of the present application can be implemented by hardware; for example, as a circuit cooperating with the processor to execute the steps or functions.

[0059] The technical features of the above-described embodiments can be combined in any manner, and to make the description concise, not all possible combinations of the technical features in the above-described embodiments are described, however, as long as the combinations of the technical features do not exist contradictions, they should be considered as the scope of the present application.

[0060] The description and application of the present application are illustrative, and are not intended to limit the scope of the present application to the above-mentioned embodiments. The effects or advantages involved in the embodiments can not be embodied in the embodiments due to various factors, and the description of the effects or advantages is not used to limit the embodiments. Variations and changes of the disclosed embodiments are possible, and various components of the embodiments are known to those skilled in the art. It should be clear to those skilled in the art that the present application can be realized in other forms, structures, arrangements, proportions, and with other components, materials and parts without departing from the spirit or essential characteristics of the present application. Other variations and changes of the disclosed embodiments can be made without departing from the scope and spirit of the present application.

Claims

1. A liquid-injected screw compressor gas compression separation pressure surplus heat recovery system, characterized by, The waste heat recovery system comprises a screw compressor, an electric motor, a clutch, a screw expander, a gas-liquid separator, a gas separation device, a first heat exchanger, a second heat exchanger and a cooler. The electric motor comprises a first output shaft and a second output shaft, the first output shaft of the electric motor is connected to the screw compressor and can drive the screw compressor to work, and the second output shaft of the electric motor is connected to the screw expander through the clutch. The input end of the screw compressor is connected to a gas inlet, and the input end of the screw compressor is also connected to a liquid injection adjusting pipeline; the first end of the liquid injection adjusting pipeline is connected to the output end of the cooler, and the second end of the liquid injection adjusting pipeline sprays cooling liquid into the screw compressor. The output end of the screw compressor is connected to the gas-liquid separator, and the gas-liquid mixture output by the screw compressor is subjected to gas-liquid separation in the gas-liquid separator; the first output end of the gas-liquid separator is connected to the first heat exchanger, and the first heat exchanger, the second heat exchanger and the cooler are connected in sequence; the high-temperature and high-pressure liquid separated from the gas-liquid separator sequentially passes through the first heat exchanger, the second heat exchanger and the cooler, and is then sprayed into the liquid injection screw compressor to realize cyclic flow. The second output end of the gas-liquid separator is connected to the gas separation device, the mixed gas separated from the gas-liquid separator enters the gas separation device, and is subjected to gas separation; the separation process releases heat to the outside, the temperature of the gas is reduced, and the tail gas separated is output through a tail gas outlet. The second output end of the gas separation device is connected to the first heat exchanger, the high-temperature and high-pressure liquid separated by the gas-liquid separator is subjected to preheating through the first heat exchanger, the product gas separated from the gas separation device acquires heat value from the first heat exchanger, the enthalpy value is increased, the recovery power of the screw expander is increased, and the temperature of the gas discharged by the screw expander is increased.

2. The liquid injection screw compressor gas compression separation waste pressure and waste heat recovery system according to claim 1, characterized in that: The waste heat recovery system further comprises a liquid injection adjusting valve and a temperature transmitter; The liquid injection adjusting pipeline is provided with a liquid injection adjusting valve, and the opening degree of the liquid injection adjusting valve is controlled by the temperature transmitter arranged at the exhaust port of the compressor; The high-temperature and high-pressure liquid separated from the gas-liquid separator sequentially passes through the first heat exchanger, the second heat exchanger and the cooler, and is then sprayed into the liquid injection screw compressor to realize cyclic flow.

3. The liquid injection screw compressor gas compression separation waste pressure and waste heat recovery system according to claim 1, characterized in that: A check valve is arranged on the screw expander discharge gas pipeline to avoid backflow of gas in the shutdown condition; the low-temperature gas discharged from the screw expander exchanges heat with the second heat exchanger to increase the temperature and increase the enthalpy value, thereby providing more suitable conditions for the subsequent gas utilization device; An inlet adjusting valve is arranged on the inlet of the screw expander, the opening degree of the inlet adjusting valve is controlled by the second pressure transmitter, and the pressure at the end of the gas utilization device is constant.

4. The liquid injection screw compressor gas compression separation waste pressure and waste heat recovery system according to claim 1, characterized in that: A pipeline is connected between the first heat exchanger and the intake regulating valve, and a bypass regulating valve is arranged, the opening degree of which is controlled by the first pressure transmitter at the rear end of the gas separation device, so as to realize the constant working pressure of the gas separation device. 5.The system according to claim 1, wherein the system further comprises a gas utilization device. In the state that the liquid level in the gas-liquid separator is reduced to the set low value, liquid enters the liquid injection screw compressor from the liquid inlet through the liquid supplement regulating valve, and then enters the gas-liquid separator, and the opening degree of the liquid supplement regulating valve is controlled by the liquid level variator. 6.The system according to claim 1, wherein the system further comprises a gas utilization device. In the state that the liquid level in the gas-liquid separator reaches the set high value, the liquid discharge regulating valve is opened, the opening degree of the liquid discharge regulating valve is controlled by the liquid level variator, and the excess liquid is discharged to the liquid discharge outlet, so as to realize the constant gas-liquid separator. 7.The system according to claim 1, wherein the system further comprises a gas utilization device. 8.The system according to claim 1, wherein the screw expander is a double-screw oil-free expander, the clutch is a freewheeling clutch, and the screw compressor is a liquid injection double-screw compressor. ​ ​

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