CN219735754U - Nitrogen deep cooling separation system - Google Patents

Nitrogen deep cooling separation system Download PDF

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Publication number
CN219735754U
CN219735754U CN202320350586.9U CN202320350586U CN219735754U CN 219735754 U CN219735754 U CN 219735754U CN 202320350586 U CN202320350586 U CN 202320350586U CN 219735754 U CN219735754 U CN 219735754U
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China
Prior art keywords
nitrogen
subcooler
expander
outlet
purifier
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CN202320350586.9U
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Chinese (zh)
Inventor
姚细俊
王景平
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Hubei Xishui Lantian United Gas Co ltd
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Hubei Xishui Lantian United Gas 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
    • F25J3/04006—Providing pressurised feed air or process streams within or from the air fractionation unit
    • F25J3/04048—Providing pressurised feed air or process streams within or from the air fractionation unit by compression of cold gaseous streams, e.g. intermediate or oxygen enriched (waste) streams
    • F25J3/0406—Providing pressurised feed air or process streams within or from the air fractionation unit by compression of cold gaseous streams, e.g. intermediate or oxygen enriched (waste) streams of 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
    • 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
    • F25J3/04006—Providing pressurised feed air or process streams within or from the air fractionation unit
    • F25J3/04012—Providing pressurised feed air or process streams within or from the air fractionation unit by compression of warm gaseous streams; details of intake or interstage cooling
    • F25J3/04018—Providing pressurised feed air or process streams within or from the air fractionation unit by compression of warm gaseous streams; details of intake or interstage cooling of main feed 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
    • 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
    • F25J3/04006—Providing pressurised feed air or process streams within or from the air fractionation unit
    • F25J3/04012—Providing pressurised feed air or process streams within or from the air fractionation unit by compression of warm gaseous streams; details of intake or interstage cooling
    • F25J3/04024—Providing pressurised feed air or process streams within or from the air fractionation unit by compression of warm gaseous streams; details of intake or interstage cooling of purified feed air, so-called boosted 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
    • 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
    • F25J3/04163—Hot end purification of the feed air
    • F25J3/04169—Hot end purification of the feed air by adsorption of the impurities
    • F25J3/04181—Regenerating the adsorbents
    • 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
    • F25J3/04333—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion using quasi-closed loop internal vapor compression refrigeration cycles, e.g. of intermediate or oxygen enriched (waste-)streams
    • F25J3/04351—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion using quasi-closed loop internal vapor compression refrigeration cycles, e.g. of intermediate or oxygen enriched (waste-)streams of nitrogen
    • F25J3/04357—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion using quasi-closed loop internal vapor compression refrigeration cycles, e.g. of intermediate or oxygen enriched (waste-)streams of nitrogen and comprising a gas work expansion loop
    • 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
    • F25J3/04375—Details relating to the work expansion, e.g. process parameter etc.
    • F25J3/04393—Details relating to the work expansion, e.g. process parameter etc. using multiple or multistage gas work expansion
    • 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
    • F25J2205/00—Processes or apparatus using other separation and/or other processing means
    • F25J2205/60—Processes or apparatus using other separation and/or other processing means using adsorption on solid adsorbents, e.g. by temperature-swing adsorption [TSA] at the hot or cold end
    • F25J2205/66—Regenerating the adsorption vessel, e.g. kind of reactivation gas
    • F25J2205/70—Heating the adsorption vessel

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Mechanical Engineering (AREA)
  • Thermal Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Separation By Low-Temperature Treatments (AREA)

Abstract

The utility model discloses a nitrogen cryogenic separation system, comprising: the system comprises an air compressor, a first expander, a second expander, a precooler, a first-stage subcooler, a second-stage subcooler and a nitrogen storage tank; the nitrogen output from the top of the rectifying tower enters the air compressor for pressurization, the inlet and the outlet of the precooler are respectively connected with the pressurization section of the first expander and the pressurization section of the second expander, the inlet and the outlet of the two-section subcooler are respectively connected with the expansion section of the first expander and the expansion section of the second expander, and the expansion section of the second expander is connected with the nitrogen storage tank. The expansion machine series supercharging technology is utilized to replace a pure water chilling unit for cooling, the refrigerating capacity of gas is greatly improved, the purposes of saving energy and reducing consumption and electric quantity loss are achieved, the expansion machine is more reasonable in arrangement, and the liquid nitrogen yield is increased.

Description

Nitrogen deep cooling separation system
Technical Field
The utility model relates to the technical field of air separation equipment, in particular to a nitrogen cryogenic separation system.
Background
The air separation system is characterized in that air is used as a raw material, the air is converted into liquid by utilizing low temperature, then inert gases such as oxygen, nitrogen, argon and the like are separated in the distillation process, and in the preparation process, nitrogen cryogenic separation is carried out in one of the processes after air filtration and cooling.
In the field of low temperature technology, the circulating refrigeration technology is extremely important traditional energy technical equipment. At present, one of main equipment in nitrogen cryogenic separation is a low-temperature turboexpander which is used as a heart unit of an air separation system, and reasonable regulation and control of refrigerating capacity and isentropic efficiency determine the running economy of the whole machine. However, in the existing nitrogen cryogenic separation system, a water chilling unit is mainly used for cooling, the auxiliary low-temperature turbine expander is arranged to cause lower refrigerating capacity, high electric quantity loss and high energy consumption, and meanwhile, the yield of liquid nitrogen is also influenced.
Disclosure of Invention
In order to solve the technical problems, the utility model provides a nitrogen cryogenic separation system. The following presents a simplified summary in order to provide a basic understanding of some aspects of the disclosed embodiments. This summary is not an extensive overview and is intended to neither identify key/critical elements nor delineate the scope of such embodiments. Its sole purpose is to present some concepts in a simplified form as a prelude to the more detailed description that is presented later.
The utility model adopts the following technical scheme:
provided is a nitrogen cryogenic separation system comprising: the system comprises an air compressor, a first expander, a second expander, a precooler, a first-stage subcooler, a second-stage subcooler and a nitrogen storage tank;
the nitrogen gas of tower top output on the rectifying column gets into the air compressor machine carries out the pressure boost, the import and the export of precooler respectively with the boost section of first expander and the boost section of second expander are connected, the boost section of second expander with one section subcooler is connected, one section subcooler with the expansion section of first expander is connected, the import and the export of two sections subcooler respectively with the expansion section of first expander and the expansion section of second expander are connected, the expansion section of second expander with the nitrogen gas storage tank is connected.
Further, the nitrogen cryogenic separation system further comprises: a condensing evaporator and a subcooler; and nitrogen output from the tower top of the lower tower of the rectifying tower enters the condensing evaporator to be condensed into liquid nitrogen, and the condensed liquid nitrogen is conveyed to the subcooler to be subcooled.
Further, a first outlet, a second outlet and a third outlet are arranged on the subcooler; the first outlet of the subcooler is connected with the inlet of the upper tower of the rectifying tower; the second outlet of the subcooler is connected with a product liquid nitrogen storage tank; the third outlet of the subcooler is connected to an argon system.
Further, the nitrogen cryogenic separation system further comprises: a liquid nitrogen subcooler and a heat exchange device; the dirty nitrogen gas that the tower top was taken out on the rectifying column is carried to the liquid nitrogen subcooler, the export of liquid nitrogen subcooler with the refrigerant import connection of heat exchange device, the refrigerant export of heat exchange device is connected with the inlet connection of water cooling tower.
Further, the nitrogen cryogenic separation system further comprises: a purifier; after the polluted nitrogen is reheated by the heat exchange equipment, one part of the polluted nitrogen enters the water cooling tower, and the other part of the polluted nitrogen is conveyed to the purifier.
Further, the purifier includes: the device comprises a heat exchanger, a plate heat exchanger, a regeneration pipeline, a purifier air compressor, a purifier supercharger and an electric heater; the refrigerant inlet of the heat exchanger is provided with a dirty nitrogen receiving device, the refrigerant outlet of the heat exchanger is connected with the refrigerant inlet of the plate heat exchanger, and the heat medium inlet of the heat exchanger is connected with the air outlet of the air compressor of the purifier; the refrigerant outlet of the plate heat exchanger is connected with the air inlet of the electric heater, and the heating medium inlet of the plate heat exchanger is connected with the air outlet of the purifier supercharger; and an air outlet of the electric heater is connected with the regeneration pipeline.
Further, the purifier further comprises: the device comprises a first adsorption cylinder and a second adsorption cylinder, wherein a regeneration air inlet of the first adsorption cylinder and a regeneration air inlet of the second adsorption cylinder are connected with the electric heater through a regeneration pipeline.
The utility model has the beneficial effects that: the expansion machine series supercharging technology is utilized to replace a pure water chilling unit for cooling, the refrigerating capacity of gas is greatly improved, the purposes of saving energy and reducing consumption and electric quantity loss are achieved, the expansion machine is more reasonable in arrangement, and the liquid nitrogen yield is increased.
Drawings
In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the utility model, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic diagram of a nitrogen cryogenic separation system of the present utility model;
FIG. 2 is a schematic diagram of the structure of the purifier of the present utility model.
Detailed Description
Embodiments of the present utility model will be described in detail below with reference to the accompanying drawings. It should be understood that the described embodiments are merely some, but not all, embodiments of the utility model. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.
As shown in fig. 1-2, in some illustrative embodiments, the present utility model provides a nitrogen cryogenic separation system comprising: an air compressor 201, a first expander 202, a second expander 203, a precooler 204, a first-stage subcooler 205, a second-stage subcooler 206 and a nitrogen storage tank 207.
Nitrogen is obtained at the top of the upper tower 114 of the rectifying tower, and nitrogen output from the top of the upper tower 114 of the rectifying tower enters the air compressor 201 for pressurization, and the pressure after pressurization is increased to 1MPA. The inlet and outlet of the precooler 204 are connected to the booster stage of the first expander 202 and the booster stage of the second expander 203, respectively. The pressure of the nitrogen after being pressurized by the air compressor 201 is pressurized to 1.5MPA after passing through the pressurizing section of the first expander 202, the temperature before entering the precooler 204 is about-22 ℃, the temperature after being cooled by the precooler 204 is reduced to about-40 ℃, and the pressure after being pressurized by the pressurizing section of the second expander 203 is increased to 4.5MPA.
The booster section of the second expander 203 is connected to a first subcooler 205, the first subcooler 205 is connected to the expansion section of the first expander 202, and the inlet and outlet of the second subcooler 206 are connected to the expansion section of the first expander 202 and the expansion section of the second expander 203, respectively. The expansion section of the second expander 203 is connected to a nitrogen reservoir 207. The pressure of the nitrogen is increased to 4.5MPA after being boosted by the boosting section of the second expander 203, the nitrogen is sent to the expansion section of the first expander 202 for expansion after being supercooled by the first subcooler 205, the temperature is reduced to about minus 100 ℃, the nitrogen is sent to the second subcooler 206, the temperature is reduced to about minus 127 ℃, and finally the nitrogen is sent to the expansion section of the second expander 203 for expansion refrigeration, and the nitrogen is sent to the nitrogen storage tank 207 after the temperature is reduced to minus 193 ℃.
The expansion machines are used for carrying out stage supercharging and cooling in series, the refrigerating capacity of gas is greatly improved, the purposes of saving energy and reducing consumption and electric quantity loss are achieved, the original pure cooling of the water chilling unit is changed into series supercharging and cooling, the electric quantity loss is greatly reduced, and the liquid nitrogen yield is increased.
The utility model provides a nitrogen cryogenic separation system, which further comprises: a condensing evaporator 208 and a subcooler 209, the outlet of the condensing evaporator 208 being connected to the inlet of the subcooler 209. The air is rectified by the lower tower to obtain nitrogen at the top of the tower, the nitrogen output by the top of the lower tower 115 of the rectifying tower enters a condensing evaporator 208 to be condensed into liquid nitrogen, the condensed liquid nitrogen is divided into two parts, one part of liquid nitrogen returns to the lower tower to be used as reflux liquid, and the other part of liquid nitrogen is conveyed to a subcooler 209 to be subcooled.
The subcooler 209 is provided with a first outlet, a second outlet and a third outlet; the first outlet of the subcooler 209 is connected to the inlet of the upper column 114 of the rectifying column; a second outlet of subcooler 209 is connected to product liquid nitrogen reservoir 210; the third outlet of the subcooler 209 is connected to an argon system 211. The air is rectified by the lower tower to obtain nitrogen at the top of the tower, the nitrogen enters the condensing evaporator 208 to be condensed into liquid nitrogen, a part of the liquid nitrogen returns to the lower tower to be used as reflux liquid, the rest liquid nitrogen is sent to the subcooler 209 to be subcooled, the subcooled liquid nitrogen is divided into three parts, a part of the liquid nitrogen is throttled to enter the upper tower to be used as reflux liquid, a part of the liquid nitrogen is pumped out as product liquid nitrogen, and the rest liquid nitrogen is sent to the argon system 211 to supplement cold energy.
The utility model provides a nitrogen cryogenic separation system, which further comprises: liquid nitrogen subcooler 212, heat exchange device 213, and purifier 215. The dirty nitrogen gas that the top of the rectifying column tower 114 was taken out is carried to liquid nitrogen subcooler 212, and the export of liquid nitrogen subcooler 212 is connected with the refrigerant import of heat exchange device 213, and the refrigerant export of heat exchange device 213 is connected with the import of water-cooling tower 214. The dirty nitrogen gas is pumped out from the upper part of the upper tower 114 of the rectifying tower, is reheated to normal temperature by the liquid nitrogen subcooler 212 and the heat exchange equipment 213, and then is sent out from the cold box, one part of the dirty nitrogen gas enters the water cooling tower 214, the water cooling tower 214 exchanges heat with water below the top of the water cooling tower, the water cooling tower 214 cools water, and the other part of the dirty nitrogen gas enters the purifier 215 to be used as the regeneration gas of the purifier.
Purifier 215 includes: the device comprises a heat exchanger 1, a plate heat exchanger 2, a regeneration pipeline, a purifier air compressor 3, a purifier booster 4, an electric heater 5, a first adsorption cylinder 6, a second adsorption cylinder 7, a purifier precooler 8 and a water cooler 9.
The first adsorption cylinder 6 and the second adsorption cylinder 7 are internally provided with activated alumina and a 13X molecular sieve, and the harmful components such as water vapor, ferric oxide, acetylene and the like in the air are adsorbed according to the temperature and pressure swing adsorption principle by utilizing the selective adsorption characteristic of the 13X molecular sieve.
The moisture saturated air firstly flows through the first adsorption cylinder 6 from bottom to top, moisture, carbon dioxide, acetylene and the like in the air are adsorbed by the molecular sieve under the pressurized condition, and the adsorption capacity of the molecular sieve can reach saturation within a certain time because the dosage of the molecular sieve is certain, namely the adsorption bed layer penetrates through, and the molecular sieve has no continuous adsorption capacity. At this time, by automatically switching the switching sequence of the valves, the air is turned to enter the second adsorption cylinder 7 to continue adsorption. At the same time, the first adsorption cylinder 6 with saturated adsorption starts regeneration, and after the pressure is released to the atmospheric pressure, heated dirty nitrogen from the electric heater 5 is introduced to heat the adsorber bed in the gas flow direction opposite to the adsorption working condition. When the second adsorption cylinder 7 is saturated, the pressure is released to the atmosphere when regeneration is needed, and heated dirty nitrogen from the electric heater 5 is introduced after the pressure is released.
The purifier 215 is operated with the gas temperature reduced as much as possible to reduce the moisture in the air, while the temperature of the contaminated nitrogen is increased as much as possible when the purifier is desorbed, so that the electric heater 5 is required to heat the contaminated nitrogen. However, if the electric heater 5 works for a long time, the stability cannot be ensured, and the energy consumption is high, so that the temperature of the electric heater is effectively reduced by adding the heat exchanger 1 and the plate heat exchanger 2 so that the electric heater is not continuously in a high temperature state.
The refrigerant inlet of the heat exchanger 1 is provided with a dirty nitrogen receiving device, and the dirty nitrogen receiving device is used for receiving dirty nitrogen from the heat exchange equipment 213, specifically, a connection mode of a flange matched pipeline can be adopted, and a dirty nitrogen conveying pipeline arranged at a refrigerant outlet of the heat exchange equipment 213 is in butt joint with the refrigerant inlet of the heat exchanger 1 through a flange, so that dirty nitrogen receiving is realized. The refrigerant outlet of the heat exchanger 1 is connected with the refrigerant inlet of the plate heat exchanger 2. The heat medium inlet of the heat exchanger 2 is connected with the air outlet of the purifier air compressor 3, and the heat medium outlet of the heat exchanger 2 is connected with the water cooler 9. The hot air at the outlet of the air compressor 3 of the purifier exchanges heat with the polluted nitrogen through the heat exchanger 1, the temperature of the hot air at the air compressor 3 of the purifier is reduced, the temperature of the hot air enters the water cooler 9 for cooling again, and the polluted nitrogen enters the plate heat exchanger 2 for heat exchange and temperature rise again after the temperature of the polluted nitrogen rises after the heat exchange of the heat exchanger 1.
The refrigerant outlet of the plate heat exchanger 2 is connected with the air inlet of the electric heater 5, the heating medium inlet of the plate heat exchanger 2 is connected with the air outlet of the purifier booster 4, and the heating medium outlet of the plate heat exchanger 2 is connected with the purifier precooler 8. After the temperature of the polluted nitrogen is increased after heat exchange of the heat exchanger 1, the polluted nitrogen enters the plate heat exchanger 2 to exchange heat with the gas at the outlet of the purifier booster 4 again, after the temperature is increased again, the polluted nitrogen enters the electric heater 5, and after the heat exchange and the temperature reduction of the hot gas of the purifier booster 4 and the polluted nitrogen, the polluted nitrogen enters the purifier precooler 8 to cool and circulate, so that the original technological process is not changed. The technology is improved on the basis of the original equipment, and the aims of increasing yield and reducing consumption can be achieved only by local transformation and optimizing the technology, so that the transformation cost is effectively controlled.
The hot air and the polluted nitrogen are subjected to step heat exchange through the outlet of the purifier air compressor 3 and the purifier booster 4, so that the temperature of the polluted nitrogen is increased, namely, the temperature of the gas entering the electric heater 5 is increased, and the service time of the electric heater 5 is shortened. Meanwhile, the impurity gas entering the purifier is controlled, the purpose of prolonging the service life of the molecular sieve and the alumina is achieved, the hydrocarbon content in the product gas is reduced, and the potential safety hazard of safety production is reduced to the greatest extent.
The air outlet of the electric heater 5 is connected with a regeneration pipeline, and the regeneration air inlets of the first adsorption cylinder 6 and the second adsorption cylinder 7 are connected with the electric heater 5 through the regeneration pipeline. The regeneration pipeline includes: an output line 301, a first input line 302 and a second input line 303.
One end of the output pipeline 301 is connected with the air outlet of the electric heater 5, the other end of the output pipeline is connected with the first input pipeline 302 and the second input pipeline 303 respectively, the first input pipeline 302 is connected with the air inlet of the first adsorption cylinder 6, and the second input pipeline 303 is connected with the air inlet of the second adsorption cylinder 7.
When the first adsorption cylinder 6 is saturated, the dirty nitrogen heated by the electric heater 5 heats the bed layer of the first adsorption cylinder 6 in the gas flow direction opposite to the adsorption working condition. The adsorbents in the adsorption particles of the original adsorbed molecular sieve are desorbed due to the temperature rise, and the water vapor, carbon dioxide, acetylene and the like desorbed under the pushing of the hot flow gas are driven out of the adsorption bed. Because the temperature of the adsorbent bed is high at this time and is not suitable for the next cycle of adsorption, unheated air or polluted nitrogen gas is introduced to cool the adsorbent bed after the heating time is completed, and the temperature of the adsorbent bed is reduced to a temperature close to that of adsorption. So far, the regeneration condition of the adsorber is completed and the next adsorption is prepared. After the second adsorption cylinder 7 is saturated, the polluted nitrogen heated by the electric heater 5 enters the second adsorption cylinder 7 for desorption operation. The two adsorbers alternately adsorb and regenerate under the working condition in turn, so that the continuous purification of air is realized.
The low-voltage electricity consumption of the electric heater 5 in the whole air separation device occupies a large proportion, the temperature of a polluted nitrogen outlet of the electric heater 5 directly influences the analysis effect of the molecular sieve, and the molecular sieve cooling peak value is a critical parameter point for measuring the analysis effect and is preferably controlled at about 160 ℃. In general, the flow control of the polluted nitrogen in the whole stage of molecular sieve analysis is set to a fixed value in advance, the flow is basically unchanged, and the molecular sieve can be said to be a continuation of the heating process in the first half stage of cold blowing, so that if the polluted nitrogen amount is properly controlled differently in the heating stage and the cold blowing stage, the effect is better, the peak value of cold blowing can be improved, and the electric energy is saved.
The foregoing is merely illustrative of the present utility model, and the present utility model is not limited thereto, and any changes or substitutions easily contemplated by those skilled in the art within the scope of the present utility model should be included in the present utility model. Therefore, the protection scope of the utility model is subject to the protection scope of the claims.

Claims (7)

1. A nitrogen cryogenic separation system comprising: the system comprises an air compressor, a first expander, a second expander, a precooler, a first-stage subcooler, a second-stage subcooler and a nitrogen storage tank;
the nitrogen gas of tower top output on the rectifying column gets into the air compressor machine carries out the pressure boost, the import and the export of precooler respectively with the boost section of first expander and the boost section of second expander are connected, the boost section of second expander with one section subcooler is connected, one section subcooler with the expansion section of first expander is connected, the import and the export of two sections subcooler respectively with the expansion section of first expander and the expansion section of second expander are connected, the expansion section of second expander with the nitrogen gas storage tank is connected.
2. The nitrogen cryogenic separation system of claim 1, further comprising: a condensing evaporator and a subcooler; and nitrogen output from the tower top of the lower tower of the rectifying tower enters the condensing evaporator to be condensed into liquid nitrogen, and the condensed liquid nitrogen is conveyed to the subcooler to be subcooled.
3. The nitrogen cryogenic separation system of claim 2, wherein the subcooler is provided with a first outlet, a second outlet, and a third outlet;
the first outlet of the subcooler is connected with the inlet of the upper tower of the rectifying tower;
the second outlet of the subcooler is connected with a product liquid nitrogen storage tank;
the third outlet of the subcooler is connected to an argon system.
4. A nitrogen cryogenic separation system according to claim 3, further comprising: a liquid nitrogen subcooler and a heat exchange device; the dirty nitrogen gas that the tower top was taken out on the rectifying column is carried to the liquid nitrogen subcooler, the export of liquid nitrogen subcooler with the refrigerant import connection of heat exchange device, the refrigerant export of heat exchange device is connected with the inlet connection of water cooling tower.
5. The nitrogen cryogenic separation system of claim 4, further comprising: a purifier; after the polluted nitrogen is reheated by the heat exchanger, one part of the polluted nitrogen enters the water cooling tower, and the other part of the polluted nitrogen is conveyed to the purifier.
6. The nitrogen cryogenic separation system of claim 5, wherein the purifier comprises: the device comprises a heat exchanger, a plate heat exchanger, a regeneration pipeline, a purifier air compressor, a purifier supercharger and an electric heater; the refrigerant inlet of the heat exchanger is provided with a dirty nitrogen receiving device, the refrigerant outlet of the heat exchanger is connected with the refrigerant inlet of the plate heat exchanger, and the heat medium inlet of the heat exchanger is connected with the air outlet of the air compressor of the purifier; the refrigerant outlet of the plate heat exchanger is connected with the air inlet of the electric heater, and the heating medium inlet of the plate heat exchanger is connected with the air outlet of the purifier supercharger; and an air outlet of the electric heater is connected with the regeneration pipeline.
7. The nitrogen cryogenic separation system of claim 6, wherein the purifier further comprises: the device comprises a first adsorption cylinder and a second adsorption cylinder, wherein a regeneration air inlet of the first adsorption cylinder and a regeneration air inlet of the second adsorption cylinder are connected with the electric heater through a regeneration pipeline.
CN202320350586.9U 2023-02-28 2023-02-28 Nitrogen deep cooling separation system Active CN219735754U (en)

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