CN114165988A - Low-pressure nitrogen preparation device and method - Google Patents

Low-pressure nitrogen preparation device and method Download PDF

Info

Publication number
CN114165988A
CN114165988A CN202111384312.3A CN202111384312A CN114165988A CN 114165988 A CN114165988 A CN 114165988A CN 202111384312 A CN202111384312 A CN 202111384312A CN 114165988 A CN114165988 A CN 114165988A
Authority
CN
China
Prior art keywords
nitrogen
low
air
tower
pressure
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
CN202111384312.3A
Other languages
Chinese (zh)
Other versions
CN114165988B (en
Inventor
任文
莫方淑
黄震宇
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Sichuan Air Separation Plant Group Co ltd
Original Assignee
Sichuan Air Separation Plant Group Co ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Sichuan Air Separation Plant Group Co ltd filed Critical Sichuan Air Separation Plant Group Co ltd
Priority to CN202111384312.3A priority Critical patent/CN114165988B/en
Publication of CN114165988A publication Critical patent/CN114165988A/en
Application granted granted Critical
Publication of CN114165988B publication Critical patent/CN114165988B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • 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
    • F25J3/04054—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 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
    • F25J3/04187—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
    • F25J3/04151—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
    • F25J3/04236—Integration of different exchangers in a single core, so-called integrated cores
    • 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
    • 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
    • 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
    • F25J3/044—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 single pressure main column system only
    • 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
    • F25J3/04763—Start-up or control of the process; Details of the apparatus used
    • F25J3/04769—Operation, control and regulation of the process; Instrumentation within the process
    • F25J3/04775—Air purification and pre-cooling
    • 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
    • F25J3/04763—Start-up or control of the process; Details of the apparatus used
    • F25J3/04769—Operation, control and regulation of the process; Instrumentation within the process
    • F25J3/04781—Pressure changing devices, e.g. for compression, expansion, liquid pumping
    • 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
    • F25J3/04763—Start-up or control of the process; Details of the apparatus used
    • F25J3/04769—Operation, control and regulation of the process; Instrumentation within the process
    • F25J3/04787—Heat exchange, e.g. main heat exchange line; Subcooler, external reboiler-condenser
    • 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
    • F25J3/04763—Start-up or control of the process; Details of the apparatus used
    • F25J3/04769—Operation, control and regulation of the process; Instrumentation within the process
    • F25J3/04793—Rectification, e.g. columns; Reboiler-condenser
    • 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
    • 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
    • F25J2200/72—Refluxing the column with at least a part of the totally condensed overhead gas
    • 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
    • F25J2210/00—Processes characterised by the type or other details of the feed stream
    • F25J2210/40—Air or oxygen enriched air, i.e. generally less than 30mol% of O2
    • 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
    • F25J2215/00—Processes characterised by the type or other details of the product stream
    • F25J2215/40—Air or oxygen enriched air, i.e. generally less than 30mol% of O2
    • 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
    • F25J2215/00—Processes characterised by the type or other details of the product stream
    • F25J2215/42—Nitrogen or special cases, e.g. multiple or low purity N2
    • 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
    • F25J2215/00—Processes characterised by the type or other details of the product stream
    • F25J2215/50—Oxygen or special cases, e.g. isotope-mixtures or low purity O2
    • 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
    • F25J2245/50—Processes or apparatus involving steps for recycling of process streams the recycled stream being oxygen

Abstract

The invention provides a low-pressure nitrogen preparation device and method, and relates to the technical field of air separation. The low-pressure nitrogen preparation device comprises a heat exchanger, a nitrogen preparation tower, a nitrogen tower condenser and a nitrogen tower evaporator which are connected through pipelines and valves. The upper part of the nitrogen making tower is connected with a liquid nitrogen eduction tube and a nitrogen eduction tube, and the evaporation side of the nitrogen tower condenser is connected with an oxygen-enriched air eduction tube. The oxygen-enriched air outlet pipe, the nitrogen outlet pipe and the cold source recycling pipe pass through the heat exchanger. The low-pressure nitrogen preparation device has low comprehensive energy consumption and high economic benefit. The method comprises the steps of introducing purified air into a heat exchanger to be cooled to obtain first low-temperature air, and sending the first low-temperature air into a nitrogen making tower. And sending part of low-pressure nitrogen at the upper part of the nitrogen making tower into a heat exchanger for reheating to obtain product nitrogen. The oxygen-enriched liquid air at the lower part of the nitrogen-making tower is divided into a first oxygen-enriched liquid air and a second oxygen-enriched liquid air. And the second oxygen-enriched liquid air is taken out from the bottom of the nitrogen tower evaporator and then is sent to the nitrogen tower condenser as a cold source. The low-pressure nitrogen preparation method is more simplified.

Description

Low-pressure nitrogen preparation device and method
Technical Field
The invention relates to the technical field of air separation, in particular to a low-pressure nitrogen preparation device and method.
Background
With the rapid development of the industries such as chemical industry, new materials, electronics and the like, the market has more and more demands on high-purity nitrogen products, some users have lower pressure demands on nitrogen, the device can be as simple as possible when the energy consumption is not large, more liquid nitrogen products can be produced by the users, and the liquid nitrogen yield can be adjusted according to the market conditions.
Disclosure of Invention
In view of the above situation, the present invention provides a method for preparing low-pressure nitrogen, which is more simplified and can meet the requirement that users hope to simplify the devices and processes required for preparing nitrogen as much as possible and produce liquid nitrogen products in large quantity under the condition that the energy consumption is not large.
Based on the same invention concept, the invention also provides a low-pressure nitrogen preparation device which is simple in structure, can produce more liquid nitrogen products while preparing nitrogen, is convenient to adjust the liquid nitrogen yield, and can effectively reduce the comprehensive energy consumption and improve the economic benefit.
In order to achieve the purpose, the invention provides the following technical scheme:
a low-pressure nitrogen preparation method mainly comprises the following steps:
s1: pretreating raw air to obtain purified air with preset pressure;
s2: introducing the purified air obtained in the step S1 into a heat exchanger to be cooled to a preset temperature to obtain first low-temperature air;
s3: feeding the first low-temperature air into the lower part of a nitrogen making tower for rectification;
rectifying in a nitrogen making tower to obtain low pressure nitrogen at preset pressure in the upper part of the nitrogen making tower and oxygen-enriched liquid air in the lower part of the nitrogen making tower;
s4: dividing the low-pressure nitrogen at the upper part of the nitrogen making tower into a first low-pressure nitrogen and a second low-pressure nitrogen;
after entering a nitrogen tower condenser at the upper part of a nitrogen making tower, the first low-pressure nitrogen is condensed into condensed liquid nitrogen, and then the condensed liquid nitrogen is divided into two parts, namely first condensed liquid nitrogen and second condensed liquid nitrogen; the first condensed liquid nitrogen flows back to the upper part of the nitrogen making tower to provide reflux liquid for rectification of the nitrogen making tower, and the second condensed liquid nitrogen is sent out as product liquid nitrogen;
the second low-pressure nitrogen enters a heat exchanger for reheating to normal temperature to obtain third low-pressure nitrogen with preset pressure, and the third low-pressure nitrogen is divided into a fourth low-pressure nitrogen and a fifth low-pressure nitrogen;
sending out the fourth low-pressure nitrogen as product nitrogen;
s5: dividing the oxygen-enriched liquid air at the lower part of the nitrogen-making tower into a first oxygen-enriched liquid air and a second oxygen-enriched liquid air;
after the first oxygen-enriched liquid air is evaporated by a nitrogen tower evaporator, the first oxygen-enriched liquid air provides ascending gas for the rectification of a nitrogen making tower;
the second oxygen-enriched liquid air is taken out from the bottom of the nitrogen tower evaporator and then enters the heat exchanger to be cooled into super-cooled oxygen-enriched liquid air;
and then the supercooled oxygen-enriched liquid air is used as a cold source and sent into a nitrogen tower condenser.
In some embodiments of the present invention, in step S4, feeding the fifth low-pressure nitrogen gas into the nitrogen compressor for pressurization, cooling to obtain a pressurized nitrogen gas, and dividing the pressurized nitrogen gas into a first pressurized nitrogen gas and a second pressurized nitrogen gas;
sending the first pressurized nitrogen into a compression end driven by an expansion machine for continuous pressurization, and then sending the first pressurized nitrogen into a cooler for cooling to obtain third pressurized nitrogen;
the third pressurized nitrogen sequentially passes through the heat exchanger and the expander and is cooled to a preset temperature, and sixth low-pressure nitrogen is obtained;
and the sixth low-pressure nitrogen and the second low-pressure nitrogen are converged and then pass through the heat exchanger together.
In some embodiments of the present invention, the second pressurized nitrogen gas is cooled by a heat exchanger to obtain a low-temperature nitrogen gas, and the low-temperature nitrogen gas is sent to a nitrogen tower evaporator at the lower part of the nitrogen making tower as a heat source.
In some embodiments of the invention, cryogenic nitrogen gas enters the nitrogen column vaporizer and is condensed into liquid nitrogen, and this liquid nitrogen is fed into the upper portion of the nitrogen column to provide reflux for rectification in the nitrogen column along with the first condensed liquid nitrogen.
In some embodiments of the invention, a part of the condensed rich liquid oxygen is extracted at the bottom of the nitrogen tower condenser as oxygen evaporation safe discharge, and the other part of the rich liquid oxygen is evaporated into oxygen-enriched air with a preset pressure; the oxygen-enriched air enters the heat exchanger to be reheated to normal temperature and then is sent out.
In some embodiments of the present invention, in step S2, the purified air obtained in step S1 is divided into first purified air and second purified air;
introducing the first purified air into a heat exchanger to be cooled to a preset temperature to obtain first low-temperature air;
feeding the second purified air into a compression end driven by an expander for pressurization and then cooling, and enabling the second purified air to sequentially pass through a heat exchanger and the expander to obtain second low-temperature air;
the second low-temperature air is firstly converged with the oxygen-enriched air, then reheated to normal temperature through the heat exchanger and then sent out.
A low pressure nitrogen production apparatus comprising: the heat exchanger, the nitrogen making tower, the nitrogen tower condenser and the nitrogen tower evaporator are connected through pipelines and valves;
the lower part of the nitrogen making tower is provided with an air inlet, the upper part of the nitrogen making tower is connected with a liquid nitrogen delivery pipe and a nitrogen delivery pipe, and the evaporation side of a nitrogen tower condenser is connected with an oxygen-enriched air delivery pipe;
the nitrogen tower condenser is arranged at the upper part of the nitrogen making tower;
the nitrogen tower evaporator is arranged at the lower part of the nitrogen making tower;
the oxygen-enriched air delivery pipe passes through the heat exchanger;
the nitrogen gas eduction tube passes through the heat exchanger;
the low-pressure nitrogen preparation device also comprises a cold source recovery pipe used for connecting the upper part and the lower part of the nitrogen preparation tower;
the cold source recycling pipe passes through the heat exchanger.
In some embodiments of the invention, the low pressure nitrogen production apparatus further comprises a nitrogen gas recovery pipe, a nitrogen press, and a heat source recovery pipe;
the nitrogen leading-out pipe, the nitrogen recovery pipe, the nitrogen compressor and the heat source recovery pipe are communicated in sequence;
the nitrogen recovery pipe is connected to the nitrogen outlet pipe, and the heat source recovery pipe is connected to the condensation side of the nitrogen tower evaporator;
the nitrogen gas eduction tube passes through the heat exchanger;
the heat source recovery pipe passes through the heat exchanger.
In some embodiments of the invention, the low pressure nitrogen production unit further comprises a first inlet pipe in communication with the air inlet, the first inlet pipe passing through the heat exchanger.
In some embodiments of the present invention, the low pressure nitrogen production apparatus further comprises a flow dividing pipe, an expander, a cooler, a second inlet pipe, and an outlet pipe;
the shunt pipe is used for connecting a compression end driven by the expansion machine and the heat source recovery pipe;
the cooler is connected with the compression end driven by the expansion machine;
the second air inlet pipe is used for connecting the cooler and the expander;
the air outlet pipe is used for connecting the expansion machine and the nitrogen gas delivery pipe.
In some embodiments of the present invention, the low pressure nitrogen production apparatus further comprises a flow dividing pipe, an expander, a cooler, a second inlet pipe, and an outlet pipe;
the shunt pipe is used for connecting a compression end driven by the expansion machine and a first air inlet pipe;
the cooler is connected with the compression end driven by the expansion machine;
the second air inlet pipe is used for connecting the cooler and the expander;
the air outlet pipe is used for connecting the expander and the oxygen-enriched air outlet pipe.
The embodiment of the invention at least has the following advantages or beneficial effects:
1. compared with the conventional single-tower nitrogen preparation device, the low-pressure nitrogen preparation device provided by the embodiment of the invention can cool and recover part of pressurized nitrogen or all of pressurized nitrogen after being pressurized and cooled by the nitrogen compressor through the heat exchanger, and the nitrogen is used as a heat source to be sent to the nitrogen tower evaporator at the lower part of the nitrogen preparation tower, condensed into liquid nitrogen by the nitrogen tower evaporator and then sent to the upper part of the nitrogen preparation tower, so that the comprehensive energy consumption of the device is reduced, and the economic benefit is improved.
2. According to the low-pressure nitrogen preparation device provided by one embodiment of the invention, the first pressurized nitrogen sequentially passes through the compression end of the expander, the heat exchanger, the expander, the heat exchanger and the nitrogen compressor to form a nitrogen refrigeration cycle, the nitrogen refrigeration cycle is relatively independent from the rectification of the nitrogen preparation tower, the quantity of the first pressurized nitrogen can be changed by adjusting the load of the nitrogen compressor, the refrigerating capacity of the device is further changed, the yield of a liquid nitrogen product is conveniently adjusted, the influence on the rectification working condition of the nitrogen preparation tower is small when the yield of the liquid nitrogen product is adjusted, the operation and control are simple, and the requirement of a user for conveniently adjusting the liquid nitrogen product according to the change of the market can be met.
3. According to the low-pressure nitrogen preparation device provided by one embodiment of the invention, the second purified air is directly sent out after sequentially passing through the compression end of the expansion machine, the heat exchanger, the expansion machine and the heat exchanger, the second purified air does not participate in rectification, the air quantity of the second purified air can be changed by adjusting the air quantity of the raw material purified air quantity so as to change the refrigerating capacity of the device, so that the yield of a liquid nitrogen product is conveniently adjusted, the influence on the rectification working condition of a nitrogen preparation tower is small when the liquid nitrogen product is adjusted, the operation and the control are simple, and the requirement of a user for conveniently adjusting the liquid nitrogen product according to the change of the market can be met.
4. Compared with the double-tower nitrogen preparation process, the method for preparing the low-pressure nitrogen provided by the embodiment of the invention is simpler, and can meet the requirement that a user hopes to simplify devices and processes required by nitrogen preparation as much as possible under the condition that the energy consumption is not large.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the specification, claims and drawings.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.
FIG. 1 is a schematic view of a low-pressure nitrogen producing apparatus provided in example 1 of the present invention;
fig. 2 is a schematic structural diagram of a low-pressure nitrogen production apparatus provided in embodiment 2 of the present invention.
Icon:
11-heat exchanger, 12-nitrogen making tower, 121-air inlet, 122-oxygen enriched air outlet, 123-liquid nitrogen outlet, 124-nitrogen outlet, 13-nitrogen tower condenser, 131-oxygen evaporation safety discharge pipe, 14-nitrogen tower evaporator, 141-liquid nitrogen riser, 15-cold source recovery pipe, 151-throttle valve, 161-nitrogen recovery pipe, 162-nitrogen compressor, 163-heat source recovery pipe, 17-first air inlet pipe, 181-shunt pipe, 182-expander, 183-cooler, 184-second air inlet pipe, 185-air outlet pipe, 186-compression end, 21-first low temperature air, 31-second low pressure nitrogen, 32-third low pressure nitrogen, 33-fourth low pressure nitrogen, 34-fifth low pressure nitrogen, 35-first pressurized nitrogen, 36-second pressurized nitrogen, 37-third pressurized nitrogen, 38-sixth low-pressure nitrogen, 39-low-temperature nitrogen, 41-first condensed liquid nitrogen, 42-second condensed liquid nitrogen,
51-heat exchanger, 52-nitrogen making tower, 521-air inlet, 522-oxygen enriched air outlet, 523-liquid nitrogen outlet, 524-nitrogen outlet, 53-nitrogen tower condenser, 531-oxygen evaporation safety discharge pipe, 54-nitrogen tower evaporator, 541-liquid nitrogen riser, 55-cold source recovery pipe, 551-throttle valve, 561-nitrogen recovery pipe, 562-nitrogen compressor, 563-heat source recovery pipe, 57-first air inlet pipe, 581-shunt pipe, 582-expander, 583-cooler, 584-second air inlet pipe, 585-air outlet pipe, 586-compression end, 61-first low temperature air, 62-first purified air, 63-second purified air, 64-second low temperature air, 71-second low pressure nitrogen, 72-third low pressure nitrogen, 73-fourth low pressure nitrogen, 74-fifth low pressure nitrogen, 79-cryogenic nitrogen, 81-first condensed liquid nitrogen, 82-second condensed liquid nitrogen.
Detailed Description
In the following, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the embodiments of the invention. Accordingly, the drawings and description are to be regarded as illustrative in nature, and not as restrictive.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the embodiments of the present invention, "a plurality" means two or more unless specifically limited otherwise.
In the embodiments of the present invention, unless otherwise explicitly specified or limited, the terms "mounted," "connected," "fixed," and the like are to be construed broadly, e.g., as being fixedly connected, detachably connected, or integrated; the connection can be mechanical connection, electrical connection or communication; either directly or indirectly through intervening media, either internally or in any other relationship. Specific meanings of the above terms in the embodiments of the present invention can be understood by those of ordinary skill in the art according to specific situations.
Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.
Example 1
Referring to fig. 1, the present embodiment provides a low-pressure nitrogen generator, which mainly includes: a heat exchanger 11, a nitrogen making tower 12, a nitrogen tower condenser 13, a nitrogen tower evaporator 14 and a cold source recycling pipe 15 for connecting the upper part and the lower part of the nitrogen making tower 12 which are connected through pipelines and valves.
The lower part of the nitrogen making tower 12 is provided with an air inlet 121, the upper part is connected with a liquid nitrogen delivery pipe 123 and a nitrogen delivery pipe 124, and the evaporation side of the nitrogen tower condenser 13 is connected with an oxygen-enriched air delivery pipe 122. The nitrogen column condenser 13 is provided at an upper portion of the nitrogen production column 12, and the nitrogen column evaporator 14 is provided at a lower portion of the nitrogen production column 12. The oxygen-enriched air outlet pipe 122, the nitrogen outlet pipe 124 and the cold source recycling pipe 15 all pass through the heat exchanger 11.
Purified air is fed into the lower part of the nitrogen production column 12 through the air inlet 121 for rectification, so that low-pressure nitrogen gas with a predetermined pressure can be obtained at the upper part of the nitrogen production column 12, and oxygen-enriched liquid air can be obtained at the lower part of the nitrogen production column 12. Part of the low-pressure nitrogen gas at the upper part of the nitrogen making tower 12 is condensed by the nitrogen tower condenser 13 and then is led out through the liquid nitrogen leading-out pipe 123, the low-pressure nitrogen gas which is not condensed by the nitrogen tower condenser 13 is led out through the nitrogen leading-out pipe 124, and the low-pressure nitrogen gas led out through the nitrogen leading-out pipe 124 can obtain the low-pressure nitrogen gas (namely, product nitrogen gas described below) with a preset pressure after passing through the heat exchanger 11. Through the setting of cold source recovery tube 15 for the low pressure nitrogen prepares the device and can take out partial oxygen-enriched liquid air of nitrogen making tower 12 lower part from the bottom of nitrogen tower evaporimeter 14, obtain the subcooling oxygen-enriched liquid air after the cooling of heat exchanger 11, send into nitrogen tower condenser 13 on nitrogen making tower 12 upper portion with the subcooling oxygen-enriched liquid air as the cold source again, with the comprehensive energy consumption of reduction device, improve economic benefits, the oxygen-enriched liquid air evaporates for the oxygen-enriched air leads out through oxygen-enriched air contact tube 122 in nitrogen tower condenser 13. .
In order to further reduce the comprehensive energy consumption of the low-pressure nitrogen preparation device and improve the economic benefit, the low-pressure nitrogen preparation device can further comprise a nitrogen gas recycling pipe 161, a nitrogen compressor 162 and a heat source recycling pipe 163. The nitrogen gas delivery pipe 124, the nitrogen gas recovery pipe 161, the nitrogen compressor 162 and the heat source recovery pipe 163 are sequentially communicated. The nitrogen gas recovery pipe 161 is connected to the nitrogen gas outlet pipe 124, and the heat source recovery pipe 163 is connected to the condensation-side inlet of the nitrogen column evaporator 14. The outlet of the condensation side of the nitrogen tower evaporator 14 is connected with a liquid nitrogen lifting pipe 141, and the outlet of the liquid nitrogen lifting pipe 141 is connected with the upper part of the nitrogen making tower 12. Nitrogen delivery line 124 and heat source recovery line 163 both pass through heat exchanger 11. After the partial low-pressure nitrogen in the nitrogen gas delivery pipe 124 is pressurized by the nitrogen compressor 162 and cooled by the heat exchanger 11 in sequence, the partial low-pressure nitrogen which enters the nitrogen tower evaporator 14 and is used as a heat source is condensed into liquid nitrogen and then is sent to the upper part of the nitrogen making tower 12 through the liquid nitrogen riser 141, and the liquid nitrogen and the first condensed liquid nitrogen 41 together provide reflux liquid for the rectification of the nitrogen making tower 12, so that the comprehensive energy consumption of the low-pressure nitrogen making device is further reduced, and the economic benefit is improved.
The low pressure nitrogen production unit may further include a first inlet pipe 17 communicating with the air inlet 121, the first inlet pipe 17 passing through the heat exchanger 11 to cool the purified air.
The low pressure nitrogen producing apparatus may further include a bypass pipe 181, an expander 182, a cooler 183, a second inlet pipe 184, and an outlet pipe 185. Bypass pipe 181 is adapted to connect driven compression end 186 of expander 182 to heat source recovery pipe 163, cooler 183 is connected to driven compression end 186 of expander 182, second inlet pipe 184 is adapted to connect cooler 183 to expander 182, and outlet pipe 185 is adapted to connect expander 182 to nitrogen delivery pipe 124. The gas in the shunt pipe 181 (hereinafter referred to as the first pressurized nitrogen 35) is continuously pressurized by the compressor 186 of the expander and is cooled by the cooler 183 to be the third pressurized nitrogen 37, the third pressurized nitrogen 37 is cooled by the heat exchanger 11 to a predetermined temperature and then enters the expander 182 for expansion and refrigeration to be the sixth low-pressure nitrogen 38, and the sixth low-pressure nitrogen 38 is returned to the heat exchanger 11 for reheating so as to recover cold.
The cold source recycling pipe 15 is provided with a throttle valve 151 so as to reasonably adjust the flow rate according to the requirement.
In order to ensure the safety of production, an oxygen evaporation safety discharge pipe 131 may be connected to the bottom of the nitrogen column condenser 13. A part of the condensed rich liquid oxygen is extracted at the bottom of the nitrogen column condenser 13 as oxygen evaporation safe discharge through the oxygen evaporation safe discharge pipe 131, and another part of the rich liquid oxygen is evaporated to oxygen-enriched air of a predetermined pressure. The oxygen-enriched air enters the heat exchanger 11 through the oxygen-enriched air outlet pipe 122 to recover cold energy, and is sent out after being reheated to normal temperature.
From the foregoing, the low-pressure nitrogen preparation device has a simple structure, and a part of nitrogen (i.e., the second pressurized nitrogen 36) pressurized by the nitrogen compressor 162 is used as a heat source of the nitrogen column evaporator 14 to provide more ascending gas for the rectification of the nitrogen column 12, so as to increase the oxygen content of the oxygen-rich liquid at the bottom of the nitrogen column 12 (i.e., reduce the nitrogen content in the oxygen-rich air sent out); the second pressurized nitrogen 36 as the heat source is condensed into liquid nitrogen by the nitrogen tower evaporator 14 and then is sent to the upper part of the nitrogen making tower 12 through the liquid nitrogen lifting pipe 141, and provides reflux liquid for the rectification of the nitrogen making tower 12 together with the first condensed liquid nitrogen 41, so that the reflux ratio of the nitrogen making tower 12 is increased, the nitrogen extraction rate of the nitrogen making tower 12 can be improved, the required raw material purified air quantity is reduced, the comprehensive energy consumption of the device is reduced, and the economic benefit is improved. Meanwhile, the first pressurized nitrogen 35 sequentially passes through the compression end 186 of the expansion machine, the heat exchanger 11, the expansion machine 182, the heat exchanger 11 and the nitrogen compressor 162 to form a nitrogen refrigeration cycle, the nitrogen refrigeration cycle is relatively independent of the rectification of the nitrogen making tower 12, the air quantity of the first pressurized nitrogen 35 can be changed by adjusting the load of the nitrogen compressor 162, so that the refrigerating capacity of the device can be changed to conveniently adjust the yield of the liquid nitrogen product (namely, the second condensed liquid nitrogen 42), the influence on the rectification working condition of the nitrogen making tower 12 is small when the yield of the liquid nitrogen product is adjusted, the operation and control are simple, and the requirement of a user for conveniently adjusting the liquid nitrogen product according to the change of the market can be met.
The embodiment also provides a low-pressure nitrogen preparation method, which adopts the low-pressure nitrogen preparation device provided by the embodiment to prepare low-pressure nitrogen. Taking the required pressure of 3barG for preparing low pressure nitrogen as an example, the low pressure nitrogen preparation method mainly comprises the following steps:
step S1: the feed air was pretreated to obtain purified air at a pressure of 3.35bar (G). The pretreatment of the raw air may include, for example, a step of compressing and purifying the raw air.
Step S2: the purified air obtained in step S1 is introduced into the heat exchanger 11 through the first inlet pipe 17 and cooled to a predetermined temperature to obtain first low-temperature air 21.
Step S3: the first low-temperature air 21 is sent to the lower part of the nitrogen making tower 12 for rectification, low-pressure nitrogen with the pressure of 3.15bar (G) is obtained at the upper part of the nitrogen making tower 12 through the rectification of the nitrogen making tower 12, and oxygen-enriched liquid air is obtained at the lower part of the nitrogen making tower 12.
Step S4: the low-pressure nitrogen gas at the upper part of the nitrogen making tower 12 is divided into a first low-pressure nitrogen gas and a second low-pressure nitrogen gas 31. The first low-pressure nitrogen gas enters a nitrogen tower condenser 13 at the upper part of a nitrogen making tower 12, is condensed into condensed liquid nitrogen, and then is divided into a first condensed liquid nitrogen 41 and a second condensed liquid nitrogen 42. The first condensed liquid nitrogen 41 flows back to the upper part of the nitrogen making tower 12 through a liquid nitrogen leading-out pipe 123 to provide reflux liquid for the rectification of the nitrogen making tower 12, and the second condensed liquid nitrogen 42 is sent out as product liquid nitrogen. The second low-pressure nitrogen 31 enters the heat exchanger 11 through the nitrogen outlet pipe 124 to be reheated to normal temperature, so as to obtain third low-pressure nitrogen 32 with the pressure of 3bar (G), and then the third low-pressure nitrogen 32 is divided into a fourth low-pressure nitrogen 33 and a fifth low-pressure nitrogen 34. A fourth low pressure nitrogen gas 33 (at a pressure of 3bar (g)) is sent as product nitrogen. And feeding the fifth low-pressure nitrogen gas 34 into a nitrogen compressor 162 for pressurization, cooling to obtain pressurized nitrogen gas, and dividing the pressurized nitrogen gas into a first pressurized nitrogen gas 35 and a second pressurized nitrogen gas 36. The first pressurized nitrogen 35 is sent to a compression end 186 driven by the expander 182 through a shunt pipe 181 to be continuously pressurized, and then is sent to a cooler 183 to be cooled, so as to obtain a third pressurized nitrogen 37. The third pressurized nitrogen 37 is cooled by the heat exchanger 11 and expanded by the expander 182 in sequence to a predetermined pressure and temperature to produce a sixth low pressure nitrogen 38. The sixth low-pressure nitrogen 38 is converged with the second low-pressure nitrogen 31 through the gas outlet pipe 185 and then is reheated to normal temperature through the heat exchanger 11 together to obtain the third low-pressure nitrogen 32 with the preset pressure to form a relatively independent nitrogen refrigeration cycle, so that the purposes of relatively independent refrigeration and rectification, convenient production of liquid nitrogen products and adjustment of the yield of the liquid nitrogen products are achieved. The second pressurized nitrogen 36 is cooled by the heat exchanger 11 to obtain low-temperature nitrogen 39, and then the low-temperature nitrogen 39 is sent to the nitrogen tower evaporator 14 at the lower part of the nitrogen making tower 12 through the heat source recovery pipe 163 as a heat source, condensed into liquid nitrogen and then sent to the upper part of the nitrogen making tower 12 through the liquid nitrogen lifting pipe 141, and provides reflux liquid for the rectification of the nitrogen making tower 12 together with the first condensed liquid nitrogen 41, so that the nitrogen extraction rate of the nitrogen making tower 12 is improved, the comprehensive energy consumption for preparing low-pressure nitrogen is reduced, and the economic benefit is improved.
Step S5: a part of the condensed rich liquid oxygen is extracted at the bottom of the nitrogen column condenser 13 as oxygen evaporation safe discharge through the oxygen evaporation safe discharge pipe 131, and another part of the rich liquid oxygen is evaporated to oxygen-enriched air of a predetermined pressure. The oxygen-enriched air enters the heat exchanger 11 through the oxygen-enriched air outlet pipe 122 to be reheated to normal temperature and then sent out. The oxygen-enriched liquid air at the lower part of the nitrogen-making tower 12 is divided into a first oxygen-enriched liquid air and a second oxygen-enriched liquid air. The first oxygen-enriched liquid air is evaporated by the nitrogen tower evaporator 14 to provide ascending gas for the rectification of the nitrogen making tower 12. After the second oxygen-enriched liquid air is taken out from the bottom of the nitrogen tower evaporator 14, the second oxygen-enriched liquid air enters the heat exchanger 11 through the cold source recycling pipe 15 to be cooled into supercooled oxygen-enriched liquid air, and then the supercooled oxygen-enriched liquid air is sent into the nitrogen tower condenser 13 as a cold source, so that the purposes of reducing energy consumption and improving economic benefits are achieved.
Compared with the conventional single-tower nitrogen preparation, the low-pressure nitrogen preparation device and method provided by the embodiment can reduce the comprehensive energy consumption for preparing nitrogen and improve the economic benefit. Compared with the double-tower nitrogen production, the device and the method for producing low-pressure nitrogen provided by the embodiment have the advantages that the energy consumption is equivalent to or slightly higher than that of the device and the method for producing low-pressure nitrogen, but the process is simpler, and the requirements that a user hopes to make the device and the process required for nitrogen production as simple as possible under the condition that the energy consumption is not large can be met. Meanwhile, the device and the method for preparing low-pressure nitrogen provided by the embodiment can be used for producing more liquid nitrogen products, the yield of the liquid nitrogen products can be conveniently adjusted according to market changes, and the control is simple.
Example 2
Referring to fig. 2, the present embodiment provides a low-pressure nitrogen generator, which mainly includes: a heat exchanger 51, a nitrogen making tower 52, a nitrogen tower condenser 53, a nitrogen tower evaporator 54, and a cold source recovery pipe 55 for connecting the upper and lower portions of the nitrogen making tower 52, which are connected by pipes and valves.
The nitrogen making tower 52 has an air inlet 521 at the lower part, a liquid nitrogen outlet 523 and a nitrogen outlet 524 connected to the upper part, and an oxygen-enriched air outlet 522 connected to the evaporation side of the nitrogen tower condenser 53. The nitrogen column condenser 53 is provided at an upper portion of the nitrogen production column 52, and the nitrogen column evaporator 54 is provided at a lower portion of the nitrogen production column 52. Oxygen-enriched air outlet pipe 522, nitrogen outlet pipe 524 and cold source recycling pipe 55 all pass through heat exchanger 51.
Purified air is fed into the lower part of the nitrogen production column 52 through the air inlet 521 for rectification, so that low-pressure nitrogen gas with a predetermined pressure can be obtained at the upper part of the nitrogen production column 52, and oxygen-enriched liquid air can be obtained at the lower part of the nitrogen production column 52. Part of the low-pressure nitrogen gas at the upper part of the nitrogen making tower 52 is condensed by the nitrogen tower condenser 53 and then is led out through the liquid nitrogen lead-out pipe 523, the low-pressure nitrogen gas which is not condensed by the nitrogen tower condenser 53 is led out through the nitrogen lead-out pipe 524, and the low-pressure nitrogen gas led out through the nitrogen lead-out pipe 524 can obtain the low-pressure nitrogen gas (namely, product nitrogen gas described below) with a preset pressure after passing through the heat exchanger 51. Through the arrangement of the cold source recycling pipe 55, the low-pressure nitrogen preparation device can take out part of the oxygen-enriched liquid air at the lower part of the nitrogen preparation tower 52 from the bottom of the nitrogen tower evaporator 54, obtain the supercooled oxygen-enriched liquid air after being cooled by the heat exchanger 51, and send the supercooled oxygen-enriched liquid air into the nitrogen tower condenser 53 at the upper part of the nitrogen preparation tower 52 as a cold source, so that the comprehensive energy consumption of the device is reduced, the economic benefit is improved, and the oxygen-enriched liquid air is evaporated in the nitrogen tower condenser 53 to be the oxygen-enriched air and is led out through the oxygen-enriched air leading-out pipe 522. .
In order to further reduce the comprehensive energy consumption of the low-pressure nitrogen preparation device and improve the economic benefit, the low-pressure nitrogen preparation device can also comprise a nitrogen gas recovery pipe 561, a nitrogen press 562 and a heat source recovery pipe 563. The nitrogen gas leading-out pipe 524, the nitrogen gas recovery pipe 561, the nitrogen compressor 562 and the heat source recovery pipe 563 are sequentially communicated. A nitrogen recovery pipe 561 is connected to the nitrogen lead-out pipe 524, and a heat source recovery pipe 563 is connected to a condensation-side inlet of the nitrogen column evaporator 54. The outlet of the condensing side of the nitrogen tower evaporator 54 is connected with a liquid nitrogen riser tube 541, and the outlet of the liquid nitrogen riser tube 541 is connected to the upper part of the nitrogen making tower 52. Both the nitrogen delivery pipe 524 and the heat source recovery pipe 563 pass through the heat exchanger 51. After a part of low-pressure nitrogen (hereinafter, fifth low-pressure nitrogen 74) in the nitrogen gas leading-out pipe 524 is pressurized by the nitrogen compressor 562 and cooled by the heat exchanger 51 in sequence, the part of the low-pressure nitrogen which enters the nitrogen tower evaporator 54 is condensed into liquid nitrogen and then is sent to the upper part of the nitrogen making tower 52 through the liquid nitrogen lifting pipe 541, and the liquid nitrogen and the first condensed liquid nitrogen 81 together provide reflux for the rectification of the nitrogen making tower 52, so that the comprehensive energy consumption of the low-pressure nitrogen making device is further reduced, and the economic benefit is improved.
The low pressure nitrogen producing device may further include a first intake pipe 57 communicating with the air inlet 521, the first intake pipe 57 passing through the heat exchanger 51 to cool the purified air.
The low pressure nitrogen producing apparatus further includes a bypass tube 581, an expander 582, a cooler 583, a second inlet tube 584, and an outlet tube 585. A bypass tube 581 is used to connect the first inlet line 57 to the driven compression end 586 of the expander 582, the cooler 583 is connected to the driven compression end 586 of the expander 582, a second inlet line 584 is used to connect the cooler 583 to the expander 582, and an outlet line 585 is used to connect the expander 582 to the oxygen enriched air outlet line 522. After part of the purified air (hereinafter, second purified air 63) passes through the compression end 586 driven by the expansion machine 582, the pressurization is continued, the cooling of the cooler 583, the cooling of the heat exchanger 51, and the expansion and refrigeration of the expansion machine 582, the second low-temperature air 64 with the preset pressure and temperature is obtained, the second low-temperature air 64 does not participate in the rectification, and the second low-temperature air is returned to the heat exchanger 11 for reheating and then sent out, so as to recover the cold energy.
The cold source recycling pipe 55 is provided with a throttle valve 551 so as to reasonably adjust the flow rate according to the requirement.
To ensure the safety of production, an oxygen evaporation safety vent 531 may be connected to the bottom of the nitrogen column condenser 53. A part of the condensed rich liquid oxygen is extracted at the bottom of the nitrogen column condenser 53 as oxygen evaporation safe discharge through the oxygen evaporation safe discharge pipe 531, and the other part of the rich liquid oxygen is evaporated to oxygen-enriched air of a predetermined pressure. The oxygen-enriched air enters the heat exchanger 51 through the oxygen-enriched air outlet pipe 522 to recover cold energy, and is sent out after being reheated to normal temperature.
From the foregoing, the low-pressure nitrogen preparation device has a simple structure, and nitrogen gas pressurized by the nitrogen compressor 562 is used as a heat source of the nitrogen column evaporator 54 to provide more ascending gas for rectification of the nitrogen column 52, so as to increase the oxygen content of the oxygen-enriched liquid space at the bottom of the nitrogen column 52 (i.e. reduce the nitrogen content in the oxygen-enriched air sent out); pressurized nitrogen as a heat source is condensed into liquid nitrogen by the nitrogen tower evaporator 54 and then is sent to the upper part of the nitrogen making tower 52 through the liquid nitrogen lifting pipe 141, and is rectified for the nitrogen making tower 52 together with the first condensed liquid nitrogen 81 to provide reflux liquid, so that the reflux ratio of the nitrogen making tower 52 is increased, the nitrogen extraction rate of the nitrogen making tower 52 can be improved, the required raw material purification air quantity is reduced, the comprehensive energy consumption of the device is reduced, and the economic benefit is improved. Meanwhile, the second purified air 63 passes through the compression end 586 of the expansion machine in sequence, the heat exchanger 51, the expansion machine 582, and the heat exchanger 51 and then is directly sent out, the second purified air 63 does not participate in rectification, the amount of air of the second purified air 63 can be changed by adjusting the raw material, namely the amount of air of the purified air, so that the refrigerating capacity of the device can be changed to conveniently adjust the yield of the liquid nitrogen product (namely the second condensed liquid nitrogen 82), the influence on the rectification working condition of the nitrogen making tower 52 during the adjustment of the liquid nitrogen product is small, the operation and control are simple, and the requirement of a user for conveniently adjusting the liquid nitrogen product according to the change of the market can be met.
The embodiment also provides a low-pressure nitrogen preparation method, which adopts the low-pressure nitrogen preparation device provided by the embodiment to prepare low-pressure nitrogen. Taking the required pressure of 3bar (g) for preparing low-pressure nitrogen as an example, the low-pressure nitrogen preparation method mainly comprises the following steps:
step S1: the feed air was pretreated to obtain purified air at a pressure of 3.35bar (G). The pretreatment of the raw air may include, for example, a step of compressing and purifying the raw air.
Step S2: the purified air obtained in step S1 is divided into first purified air 62 and second purified air 63. The first purified air 62 is introduced into the heat exchanger 51 through the first inlet pipe 57 and cooled to a predetermined temperature to obtain first low-temperature air 61. The second purified air 63 is sent through a shunt tube 581 to a compression end 586 driven by an expander 582 for pressurization and cooling, and the second purified air 63 is sequentially cooled by a heat exchanger 51 and expanded by the expander 582 to obtain a second low temperature air 64. The second low temperature air 64 is merged with the oxygen-enriched air in the oxygen-enriched air outlet pipe 522, and then is sent out after being reheated to normal temperature after being recovered by the heat exchanger 51. The second purified air 63 does not participate in rectification, so that the purposes of relatively independent refrigeration and rectification, convenient production of liquid nitrogen products and adjustment of the yield of the liquid nitrogen products are achieved.
Step S3: the first low-temperature air 61 is sent to the lower part of the nitrogen making tower 52 for rectification, low-pressure nitrogen with the pressure of 3.15bar (G) is obtained at the upper part of the nitrogen making tower 52 through the rectification of the nitrogen making tower 52, and oxygen-enriched liquid air is obtained at the lower part of the nitrogen making tower 52.
Step S4: the low-pressure nitrogen gas at the upper part of the nitrogen making tower 52 is divided into a first low-pressure nitrogen gas and a second low-pressure nitrogen gas 71. The first low-pressure nitrogen gas enters a nitrogen column condenser 53 at the upper part of the nitrogen making column 52, is condensed into condensed liquid nitrogen, and is divided into two parts, namely a first condensed liquid nitrogen 81 and a second condensed liquid nitrogen 82. The first condensed liquid nitrogen 81 flows back to the upper part of the nitrogen making tower 52 through a liquid nitrogen leading-out pipe 523 to provide reflux liquid for rectification of the nitrogen making tower 52, and the second condensed liquid nitrogen 82 is sent out as product liquid nitrogen. The second low-pressure nitrogen 71 enters the heat exchanger 51 through the nitrogen outlet pipe 524 to be reheated to normal temperature, so as to obtain a third low-pressure nitrogen 72 with the pressure of 3bar (G), and then the third low-pressure nitrogen 72 is divided into a fourth low-pressure nitrogen 73 (with the pressure of 3bar (G)) and a fifth low-pressure nitrogen 74. A fourth low pressure nitrogen 73 is sent as product nitrogen. The fifth low-pressure nitrogen 74 is pressurized by a nitrogen compressor 562 and cooled by a heat exchanger 51 to obtain low-temperature nitrogen 79, the low-temperature nitrogen 79 is sent to a nitrogen tower evaporator 54 at the lower part of the nitrogen making tower 52 through a heat source recovery pipe 563 as a heat source, the low-temperature nitrogen 79 is condensed into liquid nitrogen by the nitrogen tower evaporator 54 and then sent to the upper part of the nitrogen making tower 52 through a liquid nitrogen riser 541, and the liquid nitrogen is rectified by the nitrogen making tower 52 together with the first condensed liquid nitrogen 81 to provide reflux liquid, so that the nitrogen extraction rate of the nitrogen making tower 52 is improved, the comprehensive energy consumption for making the low-pressure nitrogen is reduced, and the economic benefit is improved.
Step S5: the oxygen-enriched liquid air at the lower part of the nitrogen-making tower 52 is divided into a first oxygen-enriched liquid air and a second oxygen-enriched liquid air. The first oxygen-enriched liquid air is vaporized by the nitrogen column vaporizer 54 to provide a lift gas for rectification in the nitrogen production column 52. After the second oxygen-enriched liquid air is taken out from the bottom of the nitrogen tower evaporator 54, the second oxygen-enriched liquid air enters the heat exchanger 51 through the cold source recycling pipe 55 to be cooled into supercooled oxygen-enriched liquid air, and then the supercooled oxygen-enriched liquid air is taken as a cold source to be sent into the nitrogen tower condenser 53, so that the purposes of reducing energy consumption and improving economic benefit are achieved.
Compared with the conventional single-tower nitrogen preparation, the low-pressure nitrogen preparation device and method provided by the embodiment can reduce the comprehensive energy consumption for preparing nitrogen and improve the economic benefit. Compared with the double-tower nitrogen production, the device and the method for producing low-pressure nitrogen provided by the embodiment have the advantages that the energy consumption is equivalent to or slightly higher than that of the device and the method for producing low-pressure nitrogen, but the process is simpler, and the requirements that a user hopes to make the device and the process required for nitrogen production as simple as possible under the condition that the energy consumption is not large can be met. Meanwhile, the device and the method for preparing low-pressure nitrogen provided by the embodiment can be used for producing more liquid nitrogen products, the yield of the liquid nitrogen products can be conveniently adjusted according to market changes, and the control is simple.
Finally, it should be noted that: the present invention is not limited to the above-described preferred embodiments, but various modifications and changes can be made by those skilled in the art, and the embodiments and features of the embodiments of the present invention can be combined with each other arbitrarily without conflict. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. A method for producing low pressure nitrogen, comprising the steps of:
s1: pretreating raw air to obtain purified air with preset pressure;
s2: introducing the purified air obtained in the step S1 into a heat exchanger to be cooled to a preset temperature to obtain first low-temperature air;
s3: feeding the first low-temperature air into the lower part of a nitrogen making tower for rectification;
rectifying in a nitrogen making tower to obtain low pressure nitrogen at preset pressure in the upper part of the nitrogen making tower and oxygen-enriched liquid air in the lower part of the nitrogen making tower;
s4: dividing the low-pressure nitrogen at the upper part of the nitrogen making tower into a first low-pressure nitrogen and a second low-pressure nitrogen;
after entering a nitrogen tower condenser at the upper part of a nitrogen making tower, the first low-pressure nitrogen is condensed into condensed liquid nitrogen, and then the condensed liquid nitrogen is divided into two parts, namely first condensed liquid nitrogen and second condensed liquid nitrogen; the first condensed liquid nitrogen flows back to the upper part of the nitrogen making tower to provide reflux liquid for rectification of the nitrogen making tower, and the second condensed liquid nitrogen is sent out as product liquid nitrogen;
the second low-pressure nitrogen enters a heat exchanger for reheating to normal temperature to obtain third low-pressure nitrogen with preset pressure, and the third low-pressure nitrogen is divided into a fourth low-pressure nitrogen and a fifth low-pressure nitrogen;
sending out the fourth low-pressure nitrogen as product nitrogen;
s5: dividing the oxygen-enriched liquid air at the lower part of the nitrogen-making tower into a first oxygen-enriched liquid air and a second oxygen-enriched liquid air;
the first oxygen-enriched liquid air is evaporated by a nitrogen tower evaporator and then provides ascending gas for rectification of the nitrogen making tower;
the second oxygen-enriched liquid air is taken out from the bottom of the nitrogen tower evaporator and then enters the heat exchanger to be cooled into super-cooled oxygen-enriched liquid air;
and then the supercooled oxygen-enriched liquid air is used as a cold source and sent into a nitrogen tower condenser.
2. The low pressure nitrogen production process according to claim 1,
in step S4, feeding the fifth low-pressure nitrogen gas into a nitrogen compressor to pressurize, cooling to obtain pressurized nitrogen gas, and dividing the pressurized nitrogen gas into a first pressurized nitrogen gas and a second pressurized nitrogen gas;
sending the first pressurized nitrogen into a compression end driven by an expansion machine for continuous pressurization, and then sending the first pressurized nitrogen into a cooler for cooling to obtain third pressurized nitrogen;
the third pressurized nitrogen sequentially passes through the heat exchanger and the expander and is cooled to a preset temperature, and sixth low-pressure nitrogen is obtained;
and the sixth low-pressure nitrogen and the second low-pressure nitrogen are converged and then pass through the heat exchanger together.
3. The method of claim 2, wherein the second pressurized nitrogen gas is cooled by a heat exchanger to obtain a low-temperature nitrogen gas, and the low-temperature nitrogen gas is fed as a heat source to a nitrogen column evaporator at a lower portion of the nitrogen column.
4. The low pressure nitrogen production method as claimed in claim 1, wherein a part of the condensed rich liquid oxygen is extracted at the bottom of the nitrogen column condenser as oxygen evaporation safety discharge, and another part of the rich liquid oxygen is evaporated to oxygen-enriched air of a predetermined pressure; the oxygen-enriched air enters the heat exchanger to be reheated to normal temperature and then is sent out.
5. The low pressure nitrogen production process according to claim 4,
in step S2, the purified air obtained in step S1 is divided into first purified air and second purified air;
introducing first purified air into a heat exchanger to be cooled to a preset temperature to obtain first low-temperature air;
feeding the second purified air into a compression end driven by an expander for pressurization and then cooling, and enabling the second purified air to sequentially pass through a heat exchanger and the expander to obtain second low-temperature air;
the second low-temperature air is firstly converged with the oxygen-enriched air, then reheated to normal temperature through a heat exchanger and then sent out.
6. A low-pressure nitrogen producing apparatus for producing low-pressure nitrogen gas by the low-pressure nitrogen producing method according to claim 1, characterized by comprising: the heat exchanger, the nitrogen making tower, the nitrogen tower condenser and the nitrogen tower evaporator are connected through pipelines and valves;
the lower part of the nitrogen making tower is provided with an air inlet, the upper part of the nitrogen making tower is connected with a liquid nitrogen delivery pipe and a nitrogen delivery pipe, and the evaporation side of the nitrogen tower condenser is connected with an oxygen-enriched air delivery pipe;
the nitrogen tower condenser is arranged at the upper part of the nitrogen making tower;
the nitrogen tower evaporator is arranged at the lower part of the nitrogen making tower;
the oxygen-enriched air outlet pipe passes through the heat exchanger;
the nitrogen leading-out pipe passes through the heat exchanger;
the low-pressure nitrogen preparation device also comprises a cold source recycling pipe used for connecting the upper part and the lower part of the nitrogen preparation tower;
the cold source recycling pipe passes through the heat exchanger.
7. The low-pressure nitrogen production apparatus according to claim 6, further comprising a nitrogen gas recovery pipe, a nitrogen press, and a heat source recovery pipe;
the nitrogen leading-out pipe, the nitrogen recovery pipe, the nitrogen press and the heat source recovery pipe are communicated in sequence;
the nitrogen recovery pipe is connected to the nitrogen outlet pipe, and the heat source recovery pipe is connected to the lower part of the nitrogen making tower;
the nitrogen leading-out pipe passes through the heat exchanger;
the heat source recovery pipe passes through the heat exchanger.
8. The low pressure nitrogen production unit of claim 7, further comprising a first intake pipe in communication with the air inlet, the first intake pipe passing through the heat exchanger.
9. The low pressure nitrogen producing apparatus according to claim 8, further comprising a flow dividing pipe, an expander, a cooler, a second gas inlet pipe, and a gas outlet pipe;
the shunt pipe is used for connecting the compression end driven by the expander and the heat source recovery pipe;
the cooler is connected with the compression end driven by the expansion machine;
the second air inlet pipe is used for connecting the cooler and the expander;
the air outlet pipe is used for connecting the expansion machine and the nitrogen gas delivery pipe.
10. The low pressure nitrogen producing apparatus according to claim 8, further comprising a flow dividing pipe, an expander, a cooler, a second gas inlet pipe, and a gas outlet pipe;
the shunt pipe is used for connecting a compression end driven by the expander and the first air inlet pipe;
the cooler is connected with the compression end driven by the expansion machine;
the second air inlet pipe is used for connecting the cooler and the expander;
the air outlet pipe is used for connecting the expander and the oxygen-enriched air outlet pipe.
CN202111384312.3A 2021-11-22 2021-11-22 Low-pressure nitrogen preparation device and method Active CN114165988B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202111384312.3A CN114165988B (en) 2021-11-22 2021-11-22 Low-pressure nitrogen preparation device and method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202111384312.3A CN114165988B (en) 2021-11-22 2021-11-22 Low-pressure nitrogen preparation device and method

Publications (2)

Publication Number Publication Date
CN114165988A true CN114165988A (en) 2022-03-11
CN114165988B CN114165988B (en) 2023-01-31

Family

ID=80479853

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202111384312.3A Active CN114165988B (en) 2021-11-22 2021-11-22 Low-pressure nitrogen preparation device and method

Country Status (1)

Country Link
CN (1) CN114165988B (en)

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5440885A (en) * 1993-02-09 1995-08-15 L'air Liquide, Societe Anonyme Pour L'etude Process and installation for the production of ultra-pure nitrogen by distillation of air
US20010054298A1 (en) * 2000-03-17 2001-12-27 Linde Aktiengesellschaft Process for obtaining gaseous and liquid nitrogen with a variable proportion of liquid product
CN101492156A (en) * 2009-03-12 2009-07-29 四川空分设备(集团)有限责任公司 Low-energy consumption nitrogen production method and apparatus
CN103123203A (en) * 2013-02-22 2013-05-29 河南开元空分集团有限公司 Method of preparing pure nitrogen by using exhaust gas with nitrogen to carry out once-more cryogenic distillation
CN108870866A (en) * 2017-05-09 2018-11-23 中海石油气电集团有限责任公司 It is a kind of to make the re-liquefied recovery process of BOG that refrigerant is suitable for LNG cargo ship using BOG
CN210399702U (en) * 2019-04-02 2020-04-24 河南国益空气液化有限公司 Air separation system
CN111141110A (en) * 2020-01-19 2020-05-12 杭州特盈能源技术发展有限公司 Low-energy-consumption medium-pressure nitrogen preparation process

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5440885A (en) * 1993-02-09 1995-08-15 L'air Liquide, Societe Anonyme Pour L'etude Process and installation for the production of ultra-pure nitrogen by distillation of air
US20010054298A1 (en) * 2000-03-17 2001-12-27 Linde Aktiengesellschaft Process for obtaining gaseous and liquid nitrogen with a variable proportion of liquid product
CN101492156A (en) * 2009-03-12 2009-07-29 四川空分设备(集团)有限责任公司 Low-energy consumption nitrogen production method and apparatus
CN103123203A (en) * 2013-02-22 2013-05-29 河南开元空分集团有限公司 Method of preparing pure nitrogen by using exhaust gas with nitrogen to carry out once-more cryogenic distillation
CN108870866A (en) * 2017-05-09 2018-11-23 中海石油气电集团有限责任公司 It is a kind of to make the re-liquefied recovery process of BOG that refrigerant is suitable for LNG cargo ship using BOG
CN210399702U (en) * 2019-04-02 2020-04-24 河南国益空气液化有限公司 Air separation system
CN111141110A (en) * 2020-01-19 2020-05-12 杭州特盈能源技术发展有限公司 Low-energy-consumption medium-pressure nitrogen preparation process

Also Published As

Publication number Publication date
CN114165988B (en) 2023-01-31

Similar Documents

Publication Publication Date Title
CN111141110B (en) Low-energy-consumption medium-pressure nitrogen preparation process
CN113883829B (en) Method and device for preparing high-purity nitrogen with low energy consumption
CN1041460C (en) Cryogenic air separation system with dual feed air side condensers
CN113405318B (en) Application method of device for producing pure nitrogen by using single rectifying tower
CN101925790A (en) Method and device for low-temperature air separation
JPH05203348A (en) Air separation by refining and its apparatus
US5337571A (en) Process and installation for the production of oxygen gas under high pressure by air distillation
CN111527361A (en) Method and equipment for producing air product based on cryogenic rectification
CN104807290A (en) Device and method for preparing low-pressure nitrogen gas by using single-tower double-backflow expansion
JPH04283390A (en) Air rectification method and equipment for producing gaseous oxygen in variable amount
CN216716763U (en) Device for producing pure nitrogen by using single rectifying tower
CN101509722A (en) Distillation method and apparatus
JP3190016B2 (en) Low-temperature distillation method for feed air producing high-pressure nitrogen
JPH0140269B2 (en)
JP2002511136A (en) Air rectification process and plant with production of argon
CN114165988B (en) Low-pressure nitrogen preparation device and method
CN110207458B (en) High-purity oxygen production device taking air as raw material and production method thereof
CN109883139B (en) Efficient argon extraction process based on oxygen-enriched air separation
CN114183997B (en) Device and method for preparing low-pressure nitrogen
CN111542723B (en) Method for producing air product based on cryogenic rectification process and air separation system
CN114440553A (en) Low-energy-consumption double-tower pure nitrogen preparation device adopting nitrogen expansion refrigeration and application method
CN103038589A (en) Krypton xenon recovery from pipeline oxygen
CN114165989A (en) Device and method for preparing medium-pressure nitrogen
CN210688919U (en) High-purity oxygen production device with air as raw material
CN114413569B (en) Double-tower nitrogen production device and method

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant