CN107641535B - Device and method for separating and purifying various gases by membrane cryogenic coupling - Google Patents
Device and method for separating and purifying various gases by membrane cryogenic coupling Download PDFInfo
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- CN107641535B CN107641535B CN201710888551.XA CN201710888551A CN107641535B CN 107641535 B CN107641535 B CN 107641535B CN 201710888551 A CN201710888551 A CN 201710888551A CN 107641535 B CN107641535 B CN 107641535B
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Abstract
The invention discloses a device and a method for separating and purifying various gases by membrane cryogenic coupling, wherein the device comprises a raw material gas treatment device, a first purification device, a second purification device and a third purification device, the raw material gas is filtered by the raw material gas treatment device to remove impurities and is subjected to oil-water separation, then the raw material gas is purified by carbon dioxide through the first purification device, then the raw material gas with the separated carbon dioxide is conveyed to the second purification device to be separated from nitrogen, natural gas and crude helium, and the third purification device is used for separating and purifying the crude helium through a low-temperature purification Dewar to obtain pure helium. The invention saves reheating energy consumption, has simple operation and convenient use, can simultaneously complete the separation and purification of carbon dioxide, nitrogen, natural gas and helium, improves the purity of product gas, gradually separates gas, effectively reduces the purification difficulty of subsequent gas, improves the gas separation and purification speed, reduces the utilization of low-temperature cold sources, gradually utilizes energy, saves energy and protects environment.
Description
Technical Field
The invention relates to a gas purification device and a method, in particular to a device and a method for separating and purifying various gases by membrane cryogenic coupling.
Background
Helium is a non-renewable noble gas, and is present in very small amounts on earth, 3ppm in air and about 3% in natural gas. China is a country extremely poor in helium, and helium has irreplaceable important application in high-technology industries such as low-temperature superconductivity and aerospace and defense technology industries and is treated as strategic material by various countries. Natural gas gradually enters the prosperous development period in the whole energy structure by virtue of the advantages of high efficiency, cleanness, convenience and the like, and the development and utilization of the clean natural gas with high heat value become the main trend of the development of the current energy-deficient times. Nitrogen is used as a gas with stable properties, has important application in chemical industry, electronic industry and national defense military industry, the rapid development of the chemical industry and the electronic industry has increasingly larger demand for high-purity nitrogen, and the efficient production of nitrogen products is urgently needed to be solved. In a few helium-containing carbon dioxide fields, only carbon dioxide is separated, helium is wasted, and the fields also contain a large amount of nitrogen and natural gas, so that the problem of development of solving the rest of gases in the separation and extraction of carbon dioxide is indispensable.
Chinese patent 200710002320.0 discloses a separation and purification apparatus for helium and natural gas, which cools natural gas containing helium and methane to produce cooled natural gas, and separates at least a portion of the helium and methane from the cooled natural gas into a helium-containing vapor and a methane-containing liquid. The device has the following defects: the multistage utilization of energy is not realized, the cold quantity of product gas is wasted, the energy consumption of a refrigerating machine is increased, the energy consumption of the device is higher, and meanwhile, the purity of the obtained crude helium product is lower. Chinese patent 201010561795.5 discloses a method for producing natural gas/liquefied natural gas by nitrogen removal of nitrogen-containing methane gas, belonging to the technical field of nitrogen removal. The method comprises the steps of precooling raw material gas, rectifying in a high-pressure tower, stripping in a low-pressure tower, reheating product gas, circulating mixed refrigerant and the like. The method has the following defects: the method is only suitable for occasions with requirements on nitrogen and natural gas, helium in the natural gas is not utilized to be made into crude helium, and meanwhile, conditions of a single-tower rectification upper tower and a single-tower rectification lower tower are mutually interfered, so that the separation is not facilitated.
Disclosure of Invention
The purpose of the invention is as follows: the invention aims to provide a device for separating and purifying various gases by membrane cryogenic coupling, which solves the problems of low energy utilization rate, high energy consumption, gas waste and low gas purity.
The invention also aims to provide a method for separating and purifying various gases by using the device for separating and purifying various gases by membrane cryogenic coupling, which solves the problems of complicated operation, gas waste, narrow application range and incomplete separation in the separation process.
The technical scheme is as follows: the device for separating and purifying a plurality of gases by membrane cryogenic coupling comprises a raw material gas treatment device, a first purification device, a second purification device and a third purification device, wherein the raw material gas treatment device is communicated with the first purification device through a pipeline, the first purification device comprises a first membrane separator and a second membrane separator, the membrane separators are respectively provided with an inlet, a permeate gas outlet and a permeate residual gas outlet, the permeate gas outlet of the first membrane separator is connected with the inlet of the second membrane separator, the permeate gas outlet of the second membrane separator is connected with a first gas storage tank through a pipeline, the permeate residual gas outlet of the second membrane separator is communicated with the inlet of the first membrane separator through a pipeline, the permeate residual gas outlet of the first membrane separator is communicated with the second purification device through a pipeline, and the second purification device comprises a high-pressure rectifying tower and a low-pressure rectifying tower, the high-pressure rectifying tower bottom outlet is connected with the low-pressure rectifying tower, the low-pressure rectifying tower top outlet is connected with a second gas storage tank through a pipeline, the low-pressure rectifying tower bottom outlet is connected with a third gas storage tank, the high-pressure rectifying tower top outlet is communicated with a third purifying device through a pipeline, the third purifying device comprises a low-temperature purifying Dewar, and the low-temperature purifying Dewar outlet is connected with a fourth gas storage tank through a pipeline.
In order to filter impurities in the raw material gas, the raw material gas treatment device comprises a filter and an oil-water separator, the filter and the oil-water separator are connected through a pipeline, and a first compressor and a first flowmeter are sequentially arranged on the pipeline along the gas flowing direction.
In order to preheat the raw material gas before the raw material gas enters the first purifying device, a heat pump condenser is further arranged on a pipeline between the raw material gas processing device and the first purifying device.
In order to completely separate carbon dioxide, a buffer tank and a second compressor are sequentially arranged on a pipeline between the first membrane separator and the second membrane separator along the gas flow direction, and a first vacuum pump is further connected to the second membrane separator.
In order to provide energy and temperature for continuously separating the feed gas from which the carbon dioxide is separated, a first molecular sieve dehydration device, a first pressure stabilizing tank, a third compressor, a heat pump evaporator, a first heat exchanger and a second heat exchanger are sequentially arranged on a pipeline between the second purification device and the first membrane separator along the gas flowing direction, and the second heat exchanger is provided with a refrigerating unit.
In order to completely purify natural gas and nitrogen, a fourth heat exchanger and a reboiler are sequentially arranged on a pipeline communicated with the low-pressure rectifying tower from the bottom outlet of the high-pressure rectifying tower along the gas flowing direction, and the pipeline communicated with the third gas storage tank of the low-pressure rectifying tower sequentially passes through the third heat exchanger, the fourth heat exchanger and the first heat exchanger along the gas flowing direction.
In order to carry out subsequent purification on the helium separated by the second purification device, a second molecular sieve dehydration device, a second pressure stabilizing tank, a first helium purity detector, a second vacuum pump, a fifth heat exchanger, a diaphragm compressor and an oil remover are sequentially arranged on a pipeline, communicated with the third purification device, at the top outlet of the high-pressure rectification tower along the gas flowing direction.
In order to purify the crude helium to obtain high-purity helium, a sixth heat exchanger, a serpentine heat exchanger, a liquid-air separator, a first activated carbon adsorber and a second activated carbon adsorber are sequentially arranged in the low-temperature purification Dewar along the gas flowing direction through a pipeline, and the first heat exchanger is communicated with the third gas storage tank after passing through the sixth heat exchanger through the pipeline.
In order to recover and store the obtained high-purity helium, the second activated carbon adsorber sequentially passes through a sixth heat exchanger, a fifth heat exchanger and a second helium purity detector along the gas flowing direction and is communicated with a fourth gas storage tank through pipelines.
The method for separating and purifying the multiple processed gases by the device for separating and purifying the multiple gases by membrane cryogenic coupling comprises the following steps:
the method comprises the following steps: the helium-containing carbon dioxide feed gas is filtered by a feed gas treatment device to remove impurities and is subjected to oil-water separation, then is purified by a first purification device through two-stage membrane separation and is recycled to a first gas storage tank, and the feed gas from which carbon dioxide is separated is conveyed to a second purification device;
step two: the second purifying device separates natural gas, nitrogen and crude helium through high-pressure rectification and low-pressure rectification, the separated and purified nitrogen and natural gas are conveyed to a second gas storage tank and a third gas storage tank, and the crude helium is conveyed to a third purifying device; (ii) a
Step three: and the third purification device separates and purifies the crude helium through a low-temperature purification Dewar, transfers the liquid nitrogen used for keeping a low-temperature environment to the second gas storage tank after heat exchange, and transfers the separated high-purity helium to the fourth gas storage tank.
The design principle is as follows: the invention is provided with the helium purifying Dewar, and the high-purity helium can be obtained after the purification Dewar is processed, so that a set of device can be used for obtaining various high-purity gases. The high-pressure rectifying tower and the low-pressure rectifying tower are arranged, the rectifying conditions are not interfered with each other, the high-pressure rectifying tower rectifies to obtain crude helium, the low-pressure rectifying tower rectifies to obtain nitrogen and natural gas, and the purity of product gas is improved. Compared with the traditional device for absorbing and resolving carbon dioxide by using an alcohol amine solution, the device for absorbing and resolving carbon dioxide by using the membrane separation is simple, reduces reheating load required by desorption, saves reheating energy consumption, is simple to operate and convenient to use, can simultaneously complete separation and purification of carbon dioxide, nitrogen, natural gas and helium, and realizes a method for obtaining four high-purity gases by using one set of device. The device has the advantages of simple operation, high separation and purification efficiency, good purification effect and high processing speed, and can be used for industrial separation and purification of carbon dioxide, nitrogen, natural gas and helium. The device separates and purifies most of carbon dioxide, nitrogen and natural gas, reduces the difficulty of subsequent helium separation and purification, improves the speed of helium separation and purification, and enables the whole device to operate efficiently. The device separates and purifies carbon dioxide firstly, and then utilizes low-temperature rectification to separate and purify nitrogen and natural gas, so that the subsequent liquid helium consumption for low-temperature adsorption is reduced, the reliability of the system is ensured, meanwhile, the utilization of a low-temperature cold source is reduced, the energy is utilized step by step in the treatment process due to the use of a plurality of heat exchangers, and the design concept of energy conservation and environmental protection is fully embodied.
Has the advantages that: the invention saves reheating energy consumption, has simple operation and convenient use, can simultaneously complete the separation and purification of carbon dioxide, nitrogen, natural gas and helium, improves the purity of product gas, gradually separates gas, effectively reduces the purification difficulty of subsequent gas, improves the gas separation and purification speed, reduces the utilization of low-temperature cold sources, gradually utilizes energy, saves energy and protects environment.
Drawings
FIG. 1 is a process flow diagram of the present invention.
Detailed Description
The present invention will be further described with reference to the accompanying drawings.
As shown in figure 1, the device provided by the invention comprises a filter 1, wherein a stop valve is connected in front of the filter 1, a raw material gas inlet 48 is connected to the upstream of the stop valve, a first compressor 2 is connected to the rear of the filter 1, an outlet pipeline of the first compressor 2 is connected with an oil-water separator 4, a first flow meter 3 and a pressure gauge are arranged on the outlet pipeline, an outlet of the oil-water separator 4 is connected into a heat pump condenser 5 through a pipeline, and an outlet of the heat pump condenser 5 is connected to an inlet of the retentate side of a first membrane separator 6 in a first purification device through an electric valve. The top of the first membrane separator 6 is provided with a pressure gauge and an emergency evacuation valve, and the residual gas outlet is connected with a pipeline and then connected into the first molecular sieve dehydration device 13 after passing through an electric valve. The permeation gas outlet is connected with a pipeline which is connected to the lower part of the buffer tank 7 through an electric valve, the bottom of the buffer tank 7 is provided with a blow-down valve, the top of the buffer tank is provided with an emergency emptying valve and a pressure gauge, the lower part of the buffer tank 7 is provided with an outlet pipeline, and the outlet of the pipeline is connected with an electric valve. The outlet pipeline of the buffer tank 7 is connected with the inlet of the second compressor 8 through an electric valve, and the outlet of the second compressor 8 is connected with a pipeline which is connected with the inlet of the residual side of the second membrane separator 9 through a pressure gauge. The top of the second membrane separator 9 is provided with a pressure gauge and an emergency evacuation valve, the outlet of the permeation side is provided with a pipeline which is sequentially connected with an electric valve, a second flow meter 11, the pressure gauge and a stop valve, and finally the lower part of the first gas storage tank, namely the carbon dioxide storage tank 12, is connected with the first gas storage tank, the bottom of the carbon dioxide storage tank 12 is provided with a blowoff valve, the top is provided with the emergency evacuation valve and the pressure gauge, the lower part of the storage tank is provided. The retentate side of the second membrane separator 9 is provided with a pipeline which is connected with the inlet of an electric valve between the heat pump condenser 5 and the first membrane separator 6 through the electric valve. The first membrane separator 6 and the second membrane separator 9 are provided with outlets and connected to a first vacuum pump 10 through pipelines, wherein membranes adopted by the first membrane separator and the second membrane separator are polyvinyl amine-piperazine composite membranes.
The outlet of the first molecular sieve dehydration device 13 is provided with a pipeline which is connected to the inlet at the lower part of the first pressure stabilizing tank 14 through a stop valve, the bottom of the first pressure stabilizing tank 14 is provided with a blow-down valve, the top of the first pressure stabilizing tank is provided with an emergency evacuation valve and a pressure gauge, the lower part of the first pressure stabilizing tank is provided with an outlet pipeline, the outlet of the pipeline is sequentially connected with an electric valve, a third compressor 15, the pressure gauge and the electric valve and is finally connected to the inlet of the heat pump evaporator 17, the heat pump evaporator 17 is additionally provided with a pipeline which is sequentially connected with a heat pump compressor 16. An outlet of the heat pump evaporator 17 is sequentially connected with inlets of a first heat exchanger 18 and a second heat exchanger 19 through pipelines, an outlet of the second heat exchanger 19 is sequentially connected with an electric valve and a pressure gauge through pipelines, and finally the outlet is connected to the bottom of the high-pressure rectifying tower 21; the second heat exchanger 19 is provided with refrigerant pipelines which are connected with two ends of the precooling unit 20, and electric valves are arranged on the pipelines; a liquid outlet is arranged at the bottom of the lower tower of the high-pressure rectifying tower 21 and is connected to the inlet of a fourth heat exchanger 26 through a pipeline, a pipeline is arranged on the top lateral line of the tower and is connected to the top lateral line of a low-pressure rectifying tower 24 after passing through a third heat exchanger 22 and an electric valve, a pipeline is arranged at the outlet of the fourth heat exchanger 26 and is connected to a reboiler 23, and the liquid is subjected to heat exchange and then is connected to the top lateral line; the top of the high-pressure rectifying tower 21 is provided with an exhaust port. The electric valve, the second molecular sieve dehydration device 31 and the stop valve are sequentially connected through pipelines and finally connected to the lower part of the second pressure stabilizing tank 32, the bottom of the second pressure stabilizing tank 32 is provided with a blow-down valve, the top of the second pressure stabilizing tank is provided with an emergency evacuation valve and a pressure gauge, and the lower part of the tank body is provided with an outlet pipeline.
Two outlet pipelines are arranged on the lateral line of the low-pressure rectifying tower 24 and are connected back to the lateral line below the outlet pipeline of the low-pressure rectifying tower 24 again after passing through an electric valve and a reboiler 23; a liquid outlet is formed in the bottom of the LNG pump 25 and is connected with the LNG pump 25 through a pipeline, an outlet pipeline of the LNG pump 25 is provided with two pipelines, one pipeline is connected to the top of the low-pressure rectifying tower 24 through an electric valve, the other pipeline is sequentially connected with an electric valve, a pressure gauge, a fourth heat exchanger 26, a third heat exchanger 19, a second heat exchanger 18, a third flow meter 27, a pressure gauge and a stop valve, and is finally connected to the lower portion of a third gas storage tank, namely a natural gas storage tank 28, a blow-down valve is arranged at the bottom of the natural gas storage tank 28, an emergency evacuation valve and the pressure gauge are; the top of the low-pressure rectifying tower 24 is provided with an exhaust port, an electric valve, a third heat exchanger 22, a fourth heat exchanger 26, a third heat exchanger 19, a second heat exchanger 18, a fourth flowmeter 29, a pressure gauge and a stop valve are sequentially connected through pipelines, and finally the lower part of a second gas storage tank, namely a nitrogen storage tank 30 is connected to the lower part of the nitrogen storage tank, a blow-down valve is arranged at the bottom of the nitrogen storage tank 30, an emergency evacuation valve and the pressure gauge are arranged at the top of the nitrogen storage tank, a nitrogen outlet 51 is arranged at the lower.
The outlet pipeline of the second pressure stabilizing tank 32 is sequentially connected with an electric valve, a pressure gauge, a first helium purity detector 33 and an electric valve and is finally connected to the inlet pipeline of a diaphragm compressor 35, the outlet of the compressor is sequentially connected with an oil remover 36, the pressure gauge, the electric valve and a sixth heat exchanger 38 through pipelines, and is finally connected to a serpentine heat exchanger 39 on the lower layer of a low-temperature purification Dewar 43; an outlet pipeline of the serpentine heat exchanger 39 is connected with the upper part of a liquid-air separator 40, the top part of the serpentine heat exchanger is connected with the top part of a first activated carbon adsorber 41 through a pipeline, the bottom part of the serpentine heat exchanger is connected with a sixth heat exchanger 38 outside a low-temperature purification Dewar 43 and a stop valve through a pipeline and then is exhausted, the bottom part of the first activated carbon adsorber 41 is connected with the bottom part of a second activated carbon adsorber 42 through a pipeline, and a top exhaust port is sequentially connected with the sixth heat exchanger 38, a fifth heat exchanger 34 and a second helium purity detector; the bottom of the lower layer of the low-temperature purification Dewar 43 is provided with a pipeline which is connected with a liquid nitrogen storage tank 44 through a pressure gauge and an electric valve, and the top of the low-temperature purification Dewar is provided with a pipeline which is connected with an inlet pipeline of a fourth flowmeter 29 after passing through a sixth heat exchanger 38 and a stop valve; two pipelines are arranged behind the second helium purity detector 45, one pipeline is connected to the outlet pipeline of the first helium purity detector 33 through a bypass electric valve and a check valve, the other pipeline is connected to the fourth gas storage tank, namely the lower part of the helium storage tank 47 through an electric valve, a flowmeter, a pressure gauge and a stop valve, a blow-down valve is arranged at the bottom of the helium storage tank 47, an emergency evacuation valve and a pressure gauge are arranged at the top of the helium storage tank 47, a helium outlet 52 is arranged at the lower part of the helium storage tank 47, and the helium outlet 52 is connected with an; the bypass electric valve is linked with a second helium purity detector 45, a second vacuum pump 37 is connected with a helium pipeline between the fifth heat exchanger 34 and the sixth heat exchanger 38, and system vacuumizing is carried out before the whole device is started.
When the device is used for purifying various gases, helium is introduced into the whole system before the whole system is started to evacuate impurity gases in the system, the first vacuum pump 10 and the second vacuum pump 37 are started after evacuation, and the first vacuum pump 10 and the second vacuum pump 37 are closed after the helium pipeline outlet of the low-temperature purification Dewar 43 and the first membrane separator 6 and the second membrane separator 9 keep a certain vacuum degree, so that the purity of helium and carbon dioxide separation and purification is ensured. The raw gas is sent into a filter 1 through the opening of a stop valve to remove solid impurities and particles in the raw gas, then sent into a first compressor 2 to be compressed, and sent into an oil-water separator 4 to be subjected to oil content and moisture removal after being compressed to about 0.6MPa and metered by a first flowmeter 3 and a pressure gauge, and the gas after being removed is sent into a heat pump condenser 5 through a pipeline to be preheated to about 50 ℃. The preheated gas is sent into a first membrane separator 6 for first-stage carbon dioxide membrane separation after the opening degree of an electric valve is controlled, and the residual gas after membrane separation is sent into a first molecular sieve dehydration device 13 through a pipeline under the control of the electric valve. The permeating gas in the first membrane separator 6 is controlled by an electric valve through an outlet pipeline at the permeating side and then is sent into a buffer tank 7, so that the stability of the system pressure and the continuity of gas transmission are ensured, and when the gas in the storage tank is in overpressure, the gas is emptied by an emergency emptying valve at the top of the tank body, so that the safety of the system and personnel is fully ensured.
Gas in the buffer tank 7 is sent to an inlet of a second compressor 8 after being controlled by an electric valve through an outlet pipeline at the lower part, the gas is sent to an inlet of a second membrane separator 9 after being compressed to 0.5MPa and monitored by a pressure gauge to carry out membrane separation of secondary carbon dioxide, membranes used in the primary membrane separation and the secondary membrane separation are high-molecular membranes for promoting transfer, and a polyvinyl amine-piperazine composite membrane is preferably selected as a membrane material for membrane separation. The permeating gas in the second membrane separator 9 is high-purity carbon dioxide gas, and is fed into a carbon dioxide storage tank 12 through an outlet pipeline at the permeating side after sequentially passing through an electric valve, a second flow meter 11, a pressure meter and a stop valve for metering control. The residual gas in the second membrane separator 9 is sent to the inlet of the first membrane separator 6 for the membrane separation process again after the opening degree of the electric valve is controlled through the outlet pipeline at the residual side.
The raw material gas of the first membrane separator 6 for completing carbon dioxide separation is connected to a first molecular sieve dehydration device 13 through a pipeline from a retentate side outlet to realize the separation of liquid components, the flow rate of the pipeline is controlled by an electric valve, and the raw material gas after completing gas-liquid separation is sent into a first pressure stabilizing tank 14, so that the stability of the system pressure is ensured, and meanwhile, the flow rate of the gas in the subsequent process is ensured to be stable. When the gas in the pressure stabilizing tank is in overpressure, the emergency evacuation valve at the top of the tank body is used for evacuation, so that the safety of a system and personnel is fully ensured.
Raw material gas in the first pressure stabilizing tank 14 flows into the third compressor 15 through a lower outlet through a pipeline, an electric valve is arranged in the pipeline to control flow, and the raw material gas is compressed to about 3MPa by the second compressor 15 and then is sent into the heat pump evaporator 17 to be condensed by partial high-boiling-point impurities after being detected and controlled by the pressure gauge and the electric valve. The heat pump evaporator 17 is connected with the heat pump compressor 16, the heat pump condenser 5 and the electronic expansion valve in sequence through refrigerant pipelines to form a refrigeration cycle, so that the supply of cold and heat required by the process is realized. The condensed gas is sent into a first heat exchanger 18 to exchange heat and precool with the separated and purified natural gas and nitrogen, the feed gas precooled by the first heat exchanger 18 enters a second heat exchanger 19 again to be cooled, the feed gas is further cooled to about-125 ℃ through heat exchange with a refrigerating unit 20, and the cooled feed gas is sent into a lower tower of a high-pressure rectifying tower 21 through a pressure gauge and an electric valve to be primarily separated. The liquid passes through a liquid outlet at the bottom of the tower, exchanges heat through a fourth heat exchanger 26, passes through a reboiler 23, and then is sent to the upper side line of the low-pressure rectifying tower 24, a pipeline is led out from the top side line of the high-pressure rectifying tower 21, and the liquid is sent to a third heat exchanger 22 for heat exchange, is throttled by a throttle valve and then enters the top of the low-pressure rectifying tower 24. Two pipelines are led out from the side line of a low-pressure rectifying tower 24 and are reboiled by a reboiler 23 and then returned to the low-pressure rectifying tower 24, the rectified nitrogen is sequentially subjected to heat exchange in a third heat exchanger 22, a fourth heat exchanger 26 and a second heat exchanger 18 through pipelines from a top exhaust port of the tower top and then is sent to a nitrogen storage tank 30, a fourth flowmeter 29 is arranged at an inlet of the nitrogen storage tank 30 for metering, a pressure gauge is used for monitoring and a stop valve is used for controlling, an electric valve is arranged at an outlet of the nitrogen storage tank 30 for controlling the gas output amount, and when the gas in the storage tank is in overpressure, an emergency evacuation valve at. After the liquid in the low-pressure rectifying tower 24 is pressurized by an LNG pump 25, the pressurized gas is sent to the bottom of the low-pressure rectifying tower 24 again through an exhaust electric valve, the pressurized liquid is sent to a natural gas storage tank 28 after passing through an electric valve and a pressure gauge to exchange heat in a fourth heat exchanger 26 and a second heat exchanger 18, a third flow meter 27 is arranged at the inlet of the natural gas storage tank 28 for metering, a pressure gauge is used for monitoring and a stop valve is used for controlling, an electric valve is arranged at the outlet of the natural gas storage tank 28 for controlling the gas output, and when the gas in the storage tank is in overpressure, an emergency evacuation valve at the.
The nitrogen and helium mixed gas which is rectified in the low-pressure rectifying tower 21 is discharged through a top exhaust port, the nitrogen and helium mixed gas is controlled by the electric motor to be sent into the second molecular sieve dehydration device 31 to be subjected to liquid phase component removal, the gas-liquid separation is completed and then the gas-liquid separation is sent into the second pressure stabilizing tank 32, the gas in the second pressure stabilizing tank 32 is sent into the fifth heat exchanger 34 through a bottom outlet through a pipeline, the pipeline is internally provided with an electric valve, a pressure gauge and a first helium purity detector 33, and the first helium purity detector 33 detects the purity of the gas helium in the second pressure stabilizing tank 32 in real time. After heat exchange with purified helium in the fifth heat exchanger 34, pre-compressed gas is pre-cooled and then sent to the diaphragm compressor 35 for compression to about 10MPa, the compressed gas is monitored by the pressure gauge and deoiled by the deoiler 36 and then sent to the sixth heat exchanger 38 on the upper layer of the low-temperature purification dewar 43 for heat exchange with the purified helium, liquid air and nitrogen, so that the temperature of the gas compressed by the diaphragm compressor 35 is effectively reduced before entering the low-temperature purification dewar 43, and at the moment, impurity gases such as oxygen and the like gradually start to be condensed, thereby realizing reasonable recycling of energy.
The lower layer of the low-temperature purification Dewar 43 is provided with a serpentine heat exchanger 39, a liquid-air separator 40, a first activated carbon absorber 41 and a second activated carbon absorber 42, the lower layer of the low-temperature purification Dewar 43 is filled with liquid nitrogen to provide a low-temperature environment, the liquid nitrogen is supplemented in real time by a liquid nitrogen storage tank 44, and the supplement amount is controlled by an electric valve on a pipeline. The mixed gas in the pipeline realizes sufficient heat exchange in the serpentine heat exchanger 39 in the purification Dewar filled with liquid nitrogen, so that oxygen and other gases in the gas are fully condensed. After the liquid air is separated by the liquid-air separator 40, the liquid air is discharged from a pipeline at the bottom of the liquid-air separator 40, the discharged liquid air is sent to the sixth heat exchanger 38 for heat exchange, and the air after heat exchange is discharged from the liquid air outlet 53. The mixed gas after liquid-air separation is sequentially conveyed to a first activated carbon adsorber 41 and a second activated carbon adsorber 42 through pipelines to carry out low-temperature adsorption on nitrogen, so that the nitrogen in the mixed gas is fully adsorbed to realize removal of the nitrogen, and the helium after adsorption is subjected to gradual recovery of cold energy through a pipeline at the top of the adsorber through a fifth heat exchanger 34 and a sixth heat exchanger 38 and then is conveyed to a helium storage tank; the lower layer of the low-temperature purification Dewar 43 is provided with a nitrogen gas discharge pipe, the nitrogen gas is changed into nitrogen gas after heat exchange between the liquid nitrogen providing the low-temperature environment and the mixed gas, the nitrogen gas is connected to the inlet of the fourth flowmeter 29 through the discharge pipe through the sixth heat exchanger 38, and the nitrogen gas is sent into the nitrogen gas storage tank 30 through a pipeline for recycling.
The outlet pipeline of the fifth heat exchanger 34 is connected with a second helium purity detector 45 and an electric valve, the second helium purity detector 45 is linked with a bypass electric valve and a helium storage tank air inlet electric valve, when the real-time purity detected by the second helium purity detector 45 does not meet the requirement, the bypass electric pipe is opened, the helium storage tank air inlet electric valve is closed, the helium with the purity not meeting the requirement is bypassed to the inlet of the fifth heat exchanger 34 through a one-way valve, the low-temperature condensation adsorption process of the helium is continued, the process is repeated, when the real-time concentration detected by the second helium purity detector 45 meets the requirement, the bypass electric valve is closed, the helium storage tank air inlet electric valve is opened, the high-purity helium is filled into the helium storage tank, and the helium meeting the.
Claims (10)
1. The device for separating and purifying various gases by membrane cryogenic coupling is characterized by comprising a raw material gas treatment device, a first purification device, a second purification device and a third purification device, wherein the raw material gas treatment device is communicated with the first purification device through a pipeline, the first purification device comprises a first membrane separator (6) and a second membrane separator (9), the two membrane separators are respectively provided with an inlet, a permeation gas outlet and a residual gas permeation outlet, the permeation gas outlet of the first membrane separator (6) is connected with the inlet of the second membrane separator (9), the permeation gas outlet of the second membrane separator (9) is connected with a first gas storage tank (12) through a pipeline, the residual gas permeation outlet of the second membrane separator (9) is communicated with the inlet of the first membrane separator (6) through a pipeline, and the residual gas permeation outlet of the first membrane separator (6) is communicated with the second purification device through a pipeline, the second purification device includes high-pressure rectifying column (21) and low pressure rectifying column (24), export and low pressure rectifying column (24) are connected at the bottom of high-pressure rectifying column (21) the tower, there is second gas storage tank (30) low pressure rectifying column (24) top of the tower export through the pipe connection, exit linkage has third gas storage tank (28) at the bottom of low pressure rectifying column (24) the tower, high-pressure rectifying column (21) top of the tower export is through pipeline and third purification device intercommunication, the third purification device includes low temperature purification dewar (43), and low temperature purification dewar (43) export has fourth gas storage tank (47) through the pipe connection.
2. The device for separating and purifying multiple gases by membrane cryogenic coupling according to claim 1, wherein the feed gas treatment device comprises a filter (1) and an oil-water separator (4), the filter (1) and the oil-water separator (4) are connected through a pipeline, and a first compressor (2) and a first flowmeter (3) are sequentially arranged on the pipeline along the gas flow direction.
3. The device for separating and purifying a plurality of gases by membrane cryogenic coupling according to claim 1, wherein a heat pump condenser (5) is further arranged on a pipeline between the feed gas treatment device and the first purifying device.
4. The device for separating and purifying a plurality of gases by membrane cryogenic coupling according to claim 1, characterized in that a buffer tank (7) and a second compressor (8) are sequentially arranged on a pipeline between the first membrane separator (6) and the second membrane separator (9) along the gas flow direction, and the second membrane separator (9) is further connected with a first vacuum pump (10).
5. The device for separating and purifying a plurality of gases by membrane cryogenic coupling according to claim 1, wherein a first molecular sieve dehydration device (13), a first pressure stabilizing tank (14), a third compressor (15), a heat pump evaporator (16), a first heat exchanger (18) and a second heat exchanger (19) are sequentially arranged on a pipeline between the second purification device and the first membrane separator (6) along the gas flow direction, and the second heat exchanger (19) is provided with a refrigerating unit (20).
6. The device for separating and purifying multiple gases by membrane cryogenic coupling according to claim 1, wherein a fourth heat exchanger (26) and a reboiler (23) are sequentially arranged on a pipeline of the high-pressure rectifying tower (21) bottom outlet communicated with the low-pressure rectifying tower (24) along a gas flow direction, and a pipeline of the low-pressure rectifying tower (24) communicated with the third gas storage tank (28) sequentially passes through the third heat exchanger (22), the fourth heat exchanger (26) and the first heat exchanger (18) along the gas flow direction.
7. The device for separating and purifying a plurality of gases by membrane cryogenic coupling according to claim 1, wherein a second molecular sieve dehydration device (31), a second surge tank (32), a first helium purity detector (33), a second vacuum pump (37), a fifth heat exchanger (34), a membrane compressor (35) and an oil remover (36) are sequentially arranged on a pipeline for communicating the top outlet of the high-pressure rectifying tower (21) with the third purification device along the gas flow direction.
8. The device for separating and purifying multiple gases by membrane cryogenic coupling according to claim 5, wherein a sixth heat exchanger (38), a serpentine heat exchanger (39), a liquid-air separator (40), a first activated carbon adsorber (41) and a second activated carbon adsorber (42) are sequentially arranged in the low-temperature purification Dewar (43) along a gas flow direction through a pipeline, and the first heat exchanger (18) is further communicated with the third gas storage tank (28) after passing through the sixth heat exchanger (38) through the pipeline.
9. The device for separating and purifying multiple gases by membrane cryogenic coupling according to claim 8, wherein the second activated carbon adsorber (42) is communicated with the fourth gas storage tank (47) through a sixth heat exchanger (38), a fifth heat exchanger (34) and a second helium purity detector (45) in sequence through pipelines along the gas flow direction.
10. The method for separating and purifying a plurality of gases by using the device for separating and purifying a plurality of gases by membrane cryogenic coupling according to claim 1, comprising the following steps of:
the method comprises the following steps: the raw material gas is filtered by a raw material gas treatment device to remove impurities and carry out oil-water separation, then the raw material gas is purified by a first purification device through two-stage membrane separation, carbon dioxide is recovered to a first gas storage tank, and the raw material gas from which the carbon dioxide is separated is conveyed to a second purification device;
step two: the second purifying device separates natural gas, nitrogen and crude helium through high-pressure rectification and low-pressure rectification, the separated and purified nitrogen and natural gas are conveyed to a second gas storage tank and a third gas storage tank, and the crude helium is conveyed to a third purifying device;
step three: and the third purification device separates and purifies the crude helium through a low-temperature purification Dewar, transfers the liquid nitrogen used for keeping a low-temperature environment to the second gas storage tank after heat exchange, and transfers the separated high-purity helium to the fourth gas storage tank.
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| CN112902555A (en) * | 2021-01-28 | 2021-06-04 | 武汉钢铁集团气体有限责任公司 | Helium low-temperature purification method and device and helium refrigeration cycle system |
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| CN1118060A (en) * | 1994-08-30 | 1996-03-06 | 中国科学院大连化学物理研究所 | Method for extracting high-pure helium from natural gas |
| CN102021056A (en) * | 2010-11-26 | 2011-04-20 | 成都赛普瑞兴科技有限公司 | Method for preparing natural gas/liquefied natural gas by denitrifying nitrogen-containing methane gas |
| CN102949911A (en) * | 2012-11-20 | 2013-03-06 | 东南大学 | Device for efficiently separating gas mixture of helium and carbon dioxide and separation method |
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| CN1118060A (en) * | 1994-08-30 | 1996-03-06 | 中国科学院大连化学物理研究所 | Method for extracting high-pure helium from natural gas |
| CN102021056A (en) * | 2010-11-26 | 2011-04-20 | 成都赛普瑞兴科技有限公司 | Method for preparing natural gas/liquefied natural gas by denitrifying nitrogen-containing methane gas |
| CN102949911A (en) * | 2012-11-20 | 2013-03-06 | 东南大学 | Device for efficiently separating gas mixture of helium and carbon dioxide and separation method |
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