CN215571596U - Double-tower rectification and low-temperature positive flow expansion nitrogen production system with pump - Google Patents

Double-tower rectification and low-temperature positive flow expansion nitrogen production system with pump Download PDF

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Publication number
CN215571596U
CN215571596U CN202121143712.0U CN202121143712U CN215571596U CN 215571596 U CN215571596 U CN 215571596U CN 202121143712 U CN202121143712 U CN 202121143712U CN 215571596 U CN215571596 U CN 215571596U
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China
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subcooler
outlet
inlet
rectifying tower
heat exchanger
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Chinese (zh)
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张行东
俞瑾
王丹
许峰杰
周凤华
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China National Air Separation Engineering Co ltd
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China National Air Separation Engineering Co ltd
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
    • F25J3/04406—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air using a dual pressure main column system
    • F25J3/04412—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air using a dual pressure main column system in a classical double column flowsheet, i.e. with thermal coupling by a main reboiler-condenser in the bottom of low pressure respectively top of high pressure column
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
    • F25J3/04151—Purification and (pre-)cooling of the feed air; recuperative heat-exchange with product streams
    • F25J3/04187—Cooling of the purified feed air by recuperative heat-exchange; Heat-exchange with product streams
    • F25J3/0423—Subcooling of liquid process streams
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
    • F25J3/04248—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion
    • F25J3/04284—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion using internal refrigeration by open-loop gas work expansion, e.g. of intermediate or oxygen enriched (waste-)streams
    • F25J3/0429—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion using internal refrigeration by open-loop gas work expansion, e.g. of intermediate or oxygen enriched (waste-)streams of feed air, e.g. used as waste or product air or expanded into an auxiliary column
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2200/00—Processes or apparatus using separation by rectification
    • F25J2200/50—Processes or apparatus using separation by rectification using multiple (re-)boiler-condensers at different heights of the column
    • F25J2200/54—Processes or apparatus using separation by rectification using multiple (re-)boiler-condensers at different heights of the column in the low pressure column of a double pressure main column system
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2235/00—Processes or apparatus involving steps for increasing the pressure or for conveying of liquid process streams
    • F25J2235/42—Processes or apparatus involving steps for increasing the pressure or for conveying of liquid process streams the fluid being nitrogen
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2245/00—Processes or apparatus involving steps for recycling of process streams
    • F25J2245/40—Processes or apparatus involving steps for recycling of process streams the recycled stream being air
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2245/00—Processes or apparatus involving steps for recycling of process streams
    • F25J2245/42—Processes or apparatus involving steps for recycling of process streams the recycled stream being nitrogen

Abstract

The utility model provides a double-tower rectification and low-temperature positive flow expansion nitrogen production system with a pump, which has the advantages of high extraction rate, low energy consumption, simple flow, easy operation and stable operation. The air cooling tower is connected with the main heat exchanger, the main heat exchanger is respectively connected with the high-pressure rectifying tower and the expansion machine, the high-pressure rectifying tower is connected with the condensation evaporator and the first subcooler, the first subcooler is connected with the low-pressure rectifying tower, the low-pressure rectifying tower is connected with the liquid nitrogen pump, the condensation evaporator and the main heat exchanger, the liquid nitrogen pump is connected with the second subcooler, the second subcooler is connected with the high-pressure rectifying tower, the condensation evaporator is connected with the second subcooler, the second subcooler is connected with the third subcooler, the third subcooler is connected with the low-pressure rectifying tower and the first subcooler, and the first subcooler is connected with the main heat exchanger.

Description

Double-tower rectification and low-temperature positive flow expansion nitrogen production system with pump
Technical Field
The utility model relates to a double-tower rectification and low-temperature positive flow expansion nitrogen production system with a pump.
Background
With the rapid increase of the economy of China, the air separation market prospect is good and the form is extremely optimistic. The demand of nitrogen as a protective gas in the industries of glass, metallurgy, electronics, chemical fiber, polysilicon and the like is rapidly increased, the requirement of energy conservation and environmental protection encouraged by the state is met by ensuring high efficiency and low energy consumption, the national low-carbon development is responded, the energy consumption is reduced as a primary target, the requirements on the energy consumption and the extraction rate of a nitrogen making device are improved, and the nitrogen making process which is high in extraction rate, low in energy consumption, simple in flow, easy to operate and stable in operation is urgently needed at present.
SUMMERY OF THE UTILITY MODEL
The utility model aims to overcome the defects in the prior art and provide the double-tower rectification and low-temperature positive flow expansion nitrogen making system with the pump, which has the advantages of reasonable structural design, high extraction rate, low energy consumption, simple flow, easiness in operation and stability in operation.
The technical scheme adopted by the utility model for solving the problems is as follows: the utility model provides a take two tower rectification of pump and low temperature positive current expansion nitrogen making system which characterized in that: the system comprises an air cooling tower, a main heat exchanger, a high-pressure rectifying tower, a condensing evaporator, a low-pressure rectifying tower, a first subcooler, a second subcooler, a third subcooler, a liquid nitrogen pump and an expander; an air outlet of the air cooling tower is connected with a hot fluid inlet of the main heat exchanger, a hot fluid outlet of the main heat exchanger is respectively connected with an air inlet of the high-pressure rectifying tower and an inlet of the expansion machine, and an outlet of the expansion machine is connected with a cold fluid inlet of the main heat exchanger; a nitrogen outlet of the high-pressure rectifying tower is respectively connected with a cold fluid inlet of the main heat exchanger and a hot fluid inlet of the condensation evaporator, a cold fluid outlet of the main heat exchanger is connected with a user pipe network, and a hot fluid outlet of the condensation evaporator is connected with a reflux inlet of the high-pressure rectifying tower; an oxygen-enriched liquid air outlet of the high-pressure rectifying tower is connected with a hot fluid inlet of the first subcooler, and a hot fluid outlet of the first subcooler is connected with an oxygen-enriched liquid air inlet of the low-pressure rectifying tower; a liquid nitrogen outlet of the low-pressure rectifying tower is connected with an inlet of a liquid nitrogen pump, an outlet of the liquid nitrogen pump is connected with a cold fluid inlet of a second subcooler, and a cold fluid outlet of the second subcooler is connected with a liquid nitrogen inlet of the high-pressure rectifying tower; an oxygen-enriched liquid air outlet of the low-pressure rectifying tower is connected with a cold fluid inlet of a condensation evaporator, a cold fluid outlet of the condensation evaporator is connected with a hot fluid inlet of a second subcooler, a hot fluid outlet of the second subcooler is connected with a hot fluid inlet of a third subcooler, and a hot fluid outlet of the third subcooler is connected with a condenser of the low-pressure rectifying tower; an oxygen-enriched gas outlet of the low-pressure rectifying tower is connected with a cold fluid inlet of a third subcooler, a cold fluid outlet of the third subcooler is connected with a cold fluid inlet of a first subcooler, and a cold fluid outlet of the first subcooler is connected with a cold fluid inlet of the main heat exchanger; and an oxygen-enriched liquid air outlet of the low-pressure rectifying tower is connected with a cold fluid inlet of the main heat exchanger.
The utility model also comprises a water replenishing pump, and the water replenishing pump is connected with the cooling water inlet of the air cooling tower.
The utility model also comprises that the inlet of the electric heater is connected with the cold fluid outlet of the main heat exchanger, and the outlet of the electric heater is connected with the regenerated gas inlet of the molecular sieve.
The high-pressure rectifying tower and the low-pressure rectifying tower both adopt regular packing towers.
The utility model also comprises an air compressor, and the outlet of the air compressor is connected with the air inlet of the air cooling tower.
The utility model also comprises an air filter, and the outlet of the air filter is connected with the inlet of the air compressor.
The utility model also comprises a molecular sieve, wherein the molecular sieve is arranged between the air cooling tower and the main heat exchanger, an air outlet of the air cooling tower is connected with an inlet of the molecular sieve, and an outlet of the molecular sieve is connected with a hot fluid inlet of the main heat exchanger.
The cold fluid outlet of the main heat exchanger is connected with the regenerated gas inlet of the molecular sieve.
Compared with the prior art, the utility model has the following advantages and effects:
1. the pressure of the nitrogen product discharged from the tower is high and can reach at least 8.5bara, and the nitrogen product is directly supplied to users after being discharged from the main heat exchanger.
2. The utility model adopts double towers to produce nitrogen, the nitrogen at the top of the high-pressure rectifying tower and the oxygen enrichment at the bottom of the low-pressure rectifying tower exchange heat through the condensing evaporator, and the liquid nitrogen at the top of the low-pressure rectifying tower is pumped into the high-pressure rectifying tower through the pump, thereby greatly improving the extraction rate of nitrogen and having obvious energy-saving effect.
3. Part of the low-temperature air returns to the main heat exchanger after being expanded by the expander to provide cold energy, the pressure after expansion is low, the expansion ratio is large, the expansion efficiency is greatly increased, and the process is simple.
4. The utility model can properly increase the working pressure of the high-pressure rectifying tower according to the requirements of users, namely, the product pressure is improved.
5. The utility model can produce at least 8bara pure nitrogen without a nitrogen compressor, the expander expands in positive flow, the utility model is simple, the operation is stable, the energy consumption is low, the number of valves to be controlled is small, and the automatic control is easy to realize.
Drawings
Fig. 1 is a schematic structural diagram of an embodiment of the present invention.
Detailed Description
The present invention will be described in further detail below by way of examples with reference to the accompanying drawings, which are illustrative of the present invention and are not to be construed as limiting the present invention.
The air conditioner comprises an air filter 1, an air compressor 2, a water replenishing pump 3, an air cooling tower 4, a molecular sieve 5, an electric heater 6, a main heat exchanger 7, a high-pressure rectifying tower 8, a condensing evaporator 9, a low-pressure rectifying tower 10, a first subcooler 11, a second subcooler 12, a third subcooler 13, a liquid nitrogen pump 14 and an expander 15.
The outlet of the air filter 1 is connected with the inlet of the air compressor 2, the outlet of the air compressor 2 is connected with the air inlet of the air cooling tower 4, the air outlet of the air cooling tower 4 is connected with the inlet of the molecular sieve 5, the outlet of the molecular sieve 5 is connected with the hot fluid inlet of the main heat exchanger 7, the hot fluid outlet of the main heat exchanger 7 is respectively connected with the bottom air inlet of the high-pressure rectifying tower 8 and the inlet of the expansion machine 15, the outlet of the expansion machine 15 is connected with the cold fluid inlet of the main heat exchanger 7, and the cold fluid outlet of the main heat exchanger 7 is connected with the regenerated gas inlet of the molecular sieve 5.
A nitrogen outlet at the top of the high-pressure rectifying tower 8 is connected with a cold fluid inlet of the main heat exchanger 7 and a hot fluid inlet of the condensation evaporator 9, a cold fluid outlet of the main heat exchanger 7 is connected with a user pipe network, and a hot fluid outlet of the condensation evaporator 9 is connected with a reflux inlet of the high-pressure rectifying tower 8; an oxygen-enriched liquid air outlet at the bottom of the high-pressure rectifying tower 8 is connected with a hot fluid inlet of the first subcooler 11, and a hot fluid outlet of the first subcooler 11 is connected with an oxygen-enriched liquid air inlet in the middle of the low-pressure rectifying tower 10.
A liquid nitrogen outlet at the top of the low-pressure rectifying tower 10 is connected with an inlet of a liquid nitrogen pump 14, an outlet of the liquid nitrogen pump 14 is connected with a cold fluid inlet of a second subcooler 12, and a cold fluid outlet of the second subcooler 12 is connected with a liquid nitrogen inlet at the top of the high-pressure rectifying tower 8; an oxygen-enriched liquid air outlet at the bottom of the low-pressure rectifying tower 10 is connected with a cold fluid inlet of a condensation evaporator 9, a cold fluid outlet of the condensation evaporator 9 is connected with a hot fluid inlet of a second subcooler 12, a hot fluid outlet of the second subcooler 12 is connected with a hot fluid inlet of a third subcooler 13, and a hot fluid outlet of the third subcooler 13 is connected with a condenser at the top of the low-pressure rectifying tower 10; an oxygen-enriched gas outlet at the top of the low-pressure rectifying tower 10 is connected with a cold fluid inlet of a third subcooler 13, a cold fluid outlet of the third subcooler 13 is connected with a cold fluid inlet of a first subcooler 11, and a cold fluid outlet of the first subcooler 11 is connected with a cold fluid inlet of the main heat exchanger 7; an oxygen-enriched liquid air outlet at the top of the low-pressure rectifying tower 10 is connected with a cold fluid inlet of the main heat exchanger 7.
The water replenishing pump 3 is connected with a cooling water inlet of the air cooling tower 4.
The high-pressure rectifying tower 8 and the low-pressure rectifying tower 10 both adopt regular packing towers, and have small resistance, high nitrogen extraction rate and strong variable load capacity.
The inlet of the electric heater 6 is connected with the cold fluid outlet of the main heat exchanger 7, and the outlet of the electric heater 6 is connected with the regeneration gas inlet of the molecular sieve 5. The electric heater 6 heats the air from the main heat exchanger 7, and the heated air enters the molecular sieve 5 as regeneration gas.
A method for producing nitrogen by double-tower rectification with a pump and low-temperature positive flow expansion comprises the following steps:
s1, raw material air enters from the inlet of the air filter 1, and is sequentially filtered by the air filter 1, compressed by the air compressor 2, cooled by the air cooling tower 4, and purified by the molecular sieve 5 to remove impurities such as moisture and carbon dioxide, the pressure is 8.85bara, the temperature is 25 ℃, and the flow rate is 5600Nm3Then the mixture enters a main heat exchanger 7 to exchange heat with the returned product nitrogen and waste gas; after a part of air is cooled to the saturation temperature of-167.3 ℃, the air enters the bottom of a high-pressure rectifying tower 8 to participate in rectification; part of the air is cooled to-110 ℃, enters an expander 15, is expanded to 120kPa.A, returns to the main heat exchanger 7 to provide cold energy, and enters the molecular sieve 5 after reheating to be used as regeneration gas.
S2, rectifying to obtain product nitrogen at the top of the high-pressure rectifying tower 8, wherein the pressure is 8.60 bara, the temperature is-171.6 ℃, and the flow is 3000 Nm/h, reheating one part of the nitrogen to normal temperature by a main heat exchanger 7, then sending the nitrogen to a user pipe network, sending the other part of the nitrogen to a condensation evaporator 9, exchanging heat with oxygen-enriched liquid air obtained at the bottom of the low-pressure rectifying tower 10, and condensing the obtained liquid nitrogen as reflux of the high-pressure rectifying tower 8 to participate in rectification; and obtaining oxygen-enriched liquid air at the bottom of the high-pressure rectifying tower 8, wherein the pressure is 870kPa.a, the temperature is-167.7 ℃, the flow rate is 2900 Nm/h, and the oxygen-enriched liquid air is subcooled by a first subcooler 11 and then throttled to enter the middle lower part of the low-pressure rectifying tower 10 for rectification again.
S3, obtaining pure liquid nitrogen at the top of the low-pressure rectifying tower 10, performing pressure of 4.90 bara, temperature of-180 ℃ and flow rate of 970Nm year, pressurizing the pure liquid nitrogen to 9 bara through a liquid nitrogen pump 14, exchanging heat through a second subcooler 12, sending the pure liquid nitrogen to the top of the high-pressure rectifying tower 8 to participate in rectification, and remarkably improving the extraction rate. Oxygen-enriched liquid air at the bottom of the low-pressure rectifying tower 10 enters the condensing evaporator 9 to be used as a cold source. Oxygen-enriched liquid air at the bottom of the condensation evaporator 9 has the pressure of 5bara, the temperature of-174 ℃ and the flow rate of 2000 Nm/h, is sequentially subcooled to-179 ℃ through the second subcooler 12 and the third subcooler 13, then flows into a condenser at the top of the low-pressure rectifying tower 10 in a throttling mode to be used as a cold source to condense nitrogen at the top of the low-pressure rectifying tower 10, the oxygen-enriched liquid air is gasified, the oxygen-enriched gas generated after gasification returns to the third subcooler 13, the first subcooler 11 and the main heat exchanger 7 in sequence to recover cold energy and reheat the oxygen-enriched gas to normal temperature, the oxygen-enriched liquid air which is not evaporated is directly sent to the main heat exchanger 7 to recover the cold energy and reheat the oxygen-enriched gas to normal temperature, and the two oxygen-enriched gases enter the molecular sieve 5 to be used as regeneration gas.
In addition, it should be noted that the specific embodiments described in the present specification may be different in the components, the shapes of the components, the names of the components, and the like, and the above description is only an illustration of the structure of the present invention. Equivalent or simple changes in the structure, characteristics and principles of the utility model are included in the protection scope of the patent. Various modifications, additions and substitutions for the specific embodiments described may be made by those skilled in the art without departing from the scope of the utility model as defined in the accompanying claims.

Claims (8)

1. The utility model provides a take two tower rectification of pump and low temperature positive current expansion nitrogen making system which characterized in that: the system comprises an air cooling tower, a main heat exchanger, a high-pressure rectifying tower, a condensing evaporator, a low-pressure rectifying tower, a first subcooler, a second subcooler, a third subcooler, a liquid nitrogen pump and an expander; an air outlet of the air cooling tower is connected with a hot fluid inlet of the main heat exchanger, a hot fluid outlet of the main heat exchanger is respectively connected with an air inlet of the high-pressure rectifying tower and an inlet of the expansion machine, and an outlet of the expansion machine is connected with a cold fluid inlet of the main heat exchanger; a nitrogen outlet of the high-pressure rectifying tower is respectively connected with a cold fluid inlet of the main heat exchanger and a hot fluid inlet of the condensation evaporator, a cold fluid outlet of the main heat exchanger is connected with a user pipe network, and a hot fluid outlet of the condensation evaporator is connected with a reflux inlet of the high-pressure rectifying tower; an oxygen-enriched liquid air outlet of the high-pressure rectifying tower is connected with a hot fluid inlet of the first subcooler, and a hot fluid outlet of the first subcooler is connected with an oxygen-enriched liquid air inlet of the low-pressure rectifying tower; a liquid nitrogen outlet of the low-pressure rectifying tower is connected with an inlet of a liquid nitrogen pump, an outlet of the liquid nitrogen pump is connected with a cold fluid inlet of a second subcooler, and a cold fluid outlet of the second subcooler is connected with a liquid nitrogen inlet of the high-pressure rectifying tower; an oxygen-enriched liquid air outlet of the low-pressure rectifying tower is connected with a cold fluid inlet of a condensation evaporator, a cold fluid outlet of the condensation evaporator is connected with a hot fluid inlet of a second subcooler, a hot fluid outlet of the second subcooler is connected with a hot fluid inlet of a third subcooler, and a hot fluid outlet of the third subcooler is connected with a condenser of the low-pressure rectifying tower; an oxygen-enriched gas outlet of the low-pressure rectifying tower is connected with a cold fluid inlet of a third subcooler, a cold fluid outlet of the third subcooler is connected with a cold fluid inlet of a first subcooler, and a cold fluid outlet of the first subcooler is connected with a cold fluid inlet of the main heat exchanger; and an oxygen-enriched liquid air outlet of the low-pressure rectifying tower is connected with a cold fluid inlet of the main heat exchanger.
2. The pumped double column rectification and cryogenic positive flow expansion nitrogen generation system of claim 1, wherein: the air cooling tower further comprises a water replenishing pump, and the water replenishing pump is connected with a cooling water inlet of the air cooling tower.
3. The pumped double column rectification and cryogenic positive flow expansion nitrogen generation system of claim 1, wherein: the device also comprises an electric heater, wherein an inlet of the electric heater is connected with a cold fluid outlet of the main heat exchanger, and an outlet of the electric heater is connected with a regenerated gas inlet of the molecular sieve.
4. The pumped double column rectification and cryogenic positive flow expansion nitrogen generation system of claim 1, wherein: the high-pressure rectifying tower and the low-pressure rectifying tower both adopt regular packed towers.
5. The pumped double column rectification and cryogenic positive flow expansion nitrogen generation system of claim 1, wherein: the air cooling tower further comprises an air compressor, and an outlet of the air compressor is connected with an air inlet of the air cooling tower.
6. The pumped double column rectification and cryogenic positive flow expansion nitrogen generation system of claim 5, wherein: the air purifier also comprises an air filter, and an outlet of the air filter is connected with an inlet of the air compressor.
7. The pumped double column rectification and cryogenic positive flow expansion nitrogen generation system of claim 1, wherein: the heat exchanger also comprises a molecular sieve, wherein the molecular sieve is arranged between the air cooling tower and the main heat exchanger, an air outlet of the air cooling tower is connected with an inlet of the molecular sieve, and an outlet of the molecular sieve is connected with a hot fluid inlet of the main heat exchanger.
8. The pumped double column rectification and cryogenic positive flow expansion nitrogen generation system of claim 7, wherein: and a cold fluid outlet of the main heat exchanger is connected with a regeneration gas inlet of the molecular sieve.
CN202121143712.0U 2021-05-26 2021-05-26 Double-tower rectification and low-temperature positive flow expansion nitrogen production system with pump Active CN215571596U (en)

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CN202121143712.0U CN215571596U (en) 2021-05-26 2021-05-26 Double-tower rectification and low-temperature positive flow expansion nitrogen production system with pump

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