CN211451560U - Low-energy-consumption medium-pressure nitrogen preparation device - Google Patents

Low-energy-consumption medium-pressure nitrogen preparation device Download PDF

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Publication number
CN211451560U
CN211451560U CN202020125895.2U CN202020125895U CN211451560U CN 211451560 U CN211451560 U CN 211451560U CN 202020125895 U CN202020125895 U CN 202020125895U CN 211451560 U CN211451560 U CN 211451560U
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nitrogen
main
heat exchanger
rectifying tower
main heat
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韦霆
何森林
杨正军
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Hangzhou Turning Energy Technology Development Co ltd
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Hangzhou Turning Energy Technology Development 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
    • F25J3/04151—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
    • F25J3/04218—Parallel arrangement of the main heat exchange line in cores having different functions, e.g. in low pressure and high pressure cores
    • F25J3/04224—Cores associated with a liquefaction or refrigeration cycle
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
    • F25J3/04151—Purification and (pre-)cooling of the feed air; recuperative heat-exchange with product streams
    • F25J3/04187—Cooling of the purified feed air by recuperative heat-exchange; Heat-exchange with product streams
    • F25J3/0423—Subcooling of liquid process streams
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
    • F25J3/04248—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion
    • F25J3/04278—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion using external refrigeration units, e.g. closed mechanical or regenerative refrigeration units
    • 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
    • F25J3/04406—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
    • F25J3/04424—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 without thermally coupled high and low pressure columns, i.e. a so-called split columns
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2235/00—Processes or apparatus involving steps for increasing the pressure or for conveying of liquid process streams
    • F25J2235/42—Processes or apparatus involving steps for increasing the pressure or for conveying of liquid process streams the fluid being nitrogen
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2245/00—Processes or apparatus involving steps for recycling of process streams
    • F25J2245/42—Processes or apparatus involving steps for recycling of process streams the recycled stream being nitrogen
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2270/00—Refrigeration techniques used
    • F25J2270/90—External refrigeration, e.g. conventional closed-loop mechanical refrigeration unit using Freon or NH3, unspecified external refrigeration

Abstract

The utility model discloses a device is prepared to low energy consumption middling pressure nitrogen gas, including filter, turbine air compressor, air precooling unit, the molecular sieve adsorber of alternate use, electric heater, main heat exchanger, low temperature refrigerator, rectifying column I, main condensation evaporimeter I, rectifying column II, main condensation evaporimeter II, pressure boost turboexpander pressure boost aftercooler, circulation nitrogen press aftercooler, liquid nitrogen pump, subcooler. Utilize the utility model discloses medium pressure nitrogen gas is prepared to the device, and the extraction rate is high, and the device energy consumption is low.

Description

Low-energy-consumption medium-pressure nitrogen preparation device
Technical Field
The utility model relates to an air separation technical field, concretely relates to device is prepared to low energy consumption middling pressure nitrogen gas.
Background
With the technical development and innovation of the industries such as chemical industry, electronics, new materials, ceramic steel industry, glass and the like, the demand for nitrogen is rapidly increased, and higher requirements on the purity of the nitrogen are also provided.
The common pure nitrogen equipment on the market at present is divided into two types: the single-tower nitrogen preparation and the double-tower nitrogen preparation are carried out, the single-tower nitrogen preparation can be used for smoothly preparing product nitrogen with certain pressure and can be directly used by users, and although the flow form is simple in structure, the device has low extraction rate and high product unit consumption, and is not suitable for the requirement of large-scale nitrogen consumption; the double-tower nitrogen preparation can prepare normal-pressure nitrogen or low-pressure nitrogen with the pressure of 0.1-0.2MpaG, the extraction rate of the device is high, the energy consumption is lower than that of single-tower nitrogen preparation, but the requirement of a user on the nitrogen pressure cannot be directly met due to lower product pressure.
SUMMERY OF THE UTILITY MODEL
The utility model aims at providing a device is prepared to low energy consumption middling pressure nitrogen gas to solve the not enough of prior art.
The utility model adopts the following technical scheme:
a low-energy consumption medium-pressure nitrogen preparation device comprises a filter, a turbine air compressor, an air precooling unit, an alternately used molecular sieve adsorber, an electric heater, a main heat exchanger, a low-temperature refrigerator, a rectifying tower I, a main condensing evaporator I, a rectifying tower II, a main condensing evaporator II, a booster turboexpander booster aftercooler, a circulating nitrogen compressor aftercooler, a liquid nitrogen pump and a subcooler,
the device comprises a filter, a turbine air compressor, an air precooling unit, an alternately used molecular sieve adsorber, an electric heater, a low-temperature refrigerator, a supercharging end of a supercharging turboexpander, a supercharging aftercooler of the supercharging turboexpander, a circulating nitrogen compressor and an aftercooler of the circulating nitrogen compressor, which are arranged outside a cold box, a main heat exchanger, a rectifying tower I, a main condensing evaporator I, a rectifying tower II, a main condensing evaporator II, the supercharging turboexpander, a liquid nitrogen pump and a subcooler are arranged in the cold box, the main condensing evaporator I is arranged on the rectifying tower I, and the main condensing evaporator II is arranged on the rectifying tower II;
the device comprises a filter, a turbine air compressor, an air precooling unit, an alternately used molecular sieve adsorber and a main heat exchanger which are sequentially connected, wherein a first part cooling outlet of the main heat exchanger is connected with a low-temperature refrigerator, the low-temperature refrigerator is connected with the main heat exchanger, and a first complete cooling outlet of the main heat exchanger is connected with a raw material air inlet at the bottom of a rectifying tower I;
a liquid-air outlet at the bottom of the rectifying tower I is connected with a subcooler, the subcooler is connected with a main condensing evaporator I, a throttle valve is arranged on a connecting pipeline of the subcooler and the main condensing evaporator I, and an oxygen-enriched air outlet of the main condensing evaporator I and a liquid-air outlet of the main condensing evaporator I are both connected with the bottom of a rectifying tower II;
a pressure nitrogen outlet at the top of the rectifying tower I is respectively connected with the main condensation evaporator I and the main heat exchanger, and a liquid nitrogen outlet of the main condensation evaporator I is connected with the top of the rectifying tower I; the main heat exchanger is connected with the circulating nitrogen press, the circulating nitrogen press is connected with a rear cooler of the circulating nitrogen press, the rear cooler of the circulating nitrogen press is respectively connected with an external medium-pressure nitrogen storage tank and a boosting end of a boosting turboexpander, the boosting end of the boosting turboexpander is connected with the boosting rear cooler of the boosting turboexpander, the boosting rear cooler of the boosting turboexpander is connected with the main heat exchanger, a second part cooling outlet of the main heat exchanger is connected with a low-temperature refrigerator, the low-temperature refrigerator is connected with the main heat exchanger, a third part cooling outlet and a second complete cooling outlet of the main heat exchanger are respectively connected with the boosting turboexpander and the top of a rectifying tower I, the boosting turboexpander is connected with the main heat exchanger, and the main heat exchanger is connected with the circulating nitrogen press; a throttle valve is arranged on a connecting pipeline between a second complete cooling outlet of the main heat exchanger and the top of the rectifying tower I;
an oxygen-rich liquid air outlet at the bottom of the rectifying tower II is connected with the main condensation evaporator II, and a throttle valve is arranged on a connecting pipeline between the oxygen-rich liquid air outlet at the bottom of the rectifying tower II and the main condensation evaporator II; the waste nitrogen outlet at the top of the rectifying tower II is connected with a subcooler, the subcooler is connected with a main heat exchanger, the main heat exchanger is respectively connected with an external emptying pipeline and an electric heater, and the electric heater is connected with a molecular sieve adsorber which is used alternately;
the nitrogen outlet at the top of the rectifying tower II is connected with the main condensation evaporator II, the liquid nitrogen outlet of the main condensation evaporator II is respectively connected with the liquid nitrogen pump, the external liquid nitrogen storage tank and the top of the rectifying tower II, and the liquid nitrogen pump is connected with the top of the rectifying tower I.
Further, the pressure of the medium-pressure nitrogen product prepared by the device is 20-36bar, and the purity is 10ppmO2The following.
The utility model has the advantages that:
1. the utility model adopts double-tower rectification, the rectification tower II is arranged for separating oxygen-enriched air and nitrogen in liquid from the rectification tower I, the separated nitrogen is condensed into liquid nitrogen through the top main condensation evaporator II, part of the liquid nitrogen is used as reflux of the rectification tower II, and part of the liquid nitrogen is introduced into the rectification tower I as reflux after being pressurized by the liquid nitrogen pump; more nitrogen products are separated by the rectification action of the rectification tower II, the reflux of the pumped liquid nitrogen increases the reflux of the rectification tower I, the separation effect of the rectification tower I is improved, the extraction rate of the device nitrogen is effectively improved, and the energy consumption of the device is reduced.
2. The utility model discloses a two main condensation evaporimeters set up main condensation evaporimeter I, and because of main condensation evaporimeter I well liquid air oxygen content is lower than rectifying column II, under the unchangeable condition that satisfies main condensation evaporimeter I heat transfer of rectifying column II rectifying pressure, can reduce rectifying column I's pressure to reduce the air pressure that gets into rectifying column I, and then reduce the device energy consumption.
3. The utility model discloses liquid nitrogen after the nitrogen gas condensation in main condensation evaporimeter II introduces rectifying column I again after the liquid nitrogen pump pressure boost and participates in the rectification, has reduced the energy consumption of device.
4. The utility model discloses draw forth nitrogen gas behind the pressure boost turbine expander pressure boost through the liquid nitrogen of cooling throttle, this share nitrogen gas pressure dynamic height, easy liquefaction when main heat exchanger is cooled by the gas that flows back, further reduction device energy consumption.
5. The utility model discloses what draw forth from rectifying column I is pressure nitrogen gas, obtains middling pressure nitrogen gas product through circulation nitrogen press pressure boost, and circulation booster compressor import pressure is high, and the compression energy consumption is low.
6. The utility model discloses increase the low temperature refrigerator, low temperature refrigerator efficiency relative altitude can provide the cold energy of low grade, reduces the heat load of main heat exchanger, reduces the energy consumption.
Drawings
Fig. 1 is a schematic structural diagram of the device of the present invention.
Detailed Description
The invention is further explained below with reference to examples and figures. The following examples are provided only for illustrating the present invention and are not intended to limit the scope of the present invention.
A low-energy-consumption medium-pressure nitrogen preparation device is shown in figure 1 and comprises a filter 1, a turbine air compressor 2, an air pre-cooling unit 3, alternately-used molecular sieve adsorbers 4, an electric heater 5, a main heat exchanger 6, a low-temperature refrigerator 7, a rectifying tower I8, a main condensation evaporator I9, a rectifying tower II10, a main condensation evaporator II11, a booster turboexpander 12, a booster turboexpander booster aftercooler 13, a circulating nitrogen compressor 14, a circulating nitrogen compressor aftercooler 15, a liquid nitrogen pump 16 and a subcooler 17, wherein the filter 1, the turbine air compressor 2, the air pre-cooling unit 3, the alternately-used molecular sieve adsorbers 4, the electric heater 5, the low-temperature refrigerator 7, a booster turboexpander 12 boosting end, a booster turboexpander booster aftercooler 13, the circulating nitrogen compressor 14 and the circulating nitrogen compressor aftercooler 15 are arranged outside a cold box, and the main heat exchanger 6, the electric heater 5, the low-temperature refrigerator 7, the rectifying tower I8, the main condensation evaporator I9, the rectifying tower II10, the main condensation evaporator II11, the booster turboexpander 12, the liquid nitrogen pump 16 and the subcooler 17 are arranged in the cold box, the main condensation evaporator I9 is arranged above the rectifying tower I8, and the main condensation evaporator II11 is arranged above the rectifying tower II 10;
the filter 1, the turbine air compressor 2, the air precooling unit 3, the alternately used molecular sieve adsorber 4 and the main heat exchanger 6 are sequentially connected, a first part cooling outlet of the main heat exchanger 6 is connected with the low-temperature refrigerator 7, the low-temperature refrigerator 7 is connected with the main heat exchanger 6, and a first complete cooling outlet of the main heat exchanger 6 is connected with a raw material air inlet at the bottom of the rectifying tower I8;
a liquid-air outlet at the bottom of the rectifying tower I8 is connected with a subcooler 17, the subcooler 17 is connected with a main condensation evaporator I9, a throttle valve is arranged on a connecting pipeline between the subcooler 17 and the main condensation evaporator I9, and an oxygen-enriched air outlet of the main condensation evaporator I9 and a liquid-air outlet of the main condensation evaporator I9 are both connected with the bottom of a rectifying tower II 10;
a pressure nitrogen outlet at the top of the rectifying tower I8 is respectively connected with the main condensation evaporator I9 and the main heat exchanger 6, and a liquid nitrogen outlet of the main condensation evaporator I9 is connected with the top of the rectifying tower I8; the main heat exchanger 6 is connected with the circulating nitrogen press 14, the circulating nitrogen press 14 is connected with a circulating nitrogen press aftercooler 15, the circulating nitrogen press aftercooler 15 is respectively connected with an external medium-pressure nitrogen storage tank and a boosting end of a boosting turboexpander 12, the boosting end of the boosting turboexpander 12 is connected with a boosting aftercooler 13 of the boosting turboexpander, the boosting aftercooler 13 of the boosting turboexpander is connected with the main heat exchanger 6, a second part cooling outlet of the main heat exchanger 6 is connected with a low-temperature refrigerator 7, the low-temperature refrigerator 7 is connected with the main heat exchanger 6, a third part cooling outlet and a second complete cooling outlet of the main heat exchanger 6 are respectively connected with the boosting turboexpander 12 and the top of a rectifying tower I8, the boosting turboexpander 12 is connected with the main heat exchanger 6, and the main heat exchanger 6 is connected to the circulating nitrogen press 14; a throttle valve is arranged on a connecting pipeline between a second complete cooling outlet of the main heat exchanger 6 and the top of the rectifying tower I8;
an oxygen-rich liquid air outlet at the bottom of the rectifying tower II10 is connected with the main condensation evaporator II11, and a throttle valve is arranged on a connecting pipeline between the oxygen-rich liquid air outlet at the bottom of the rectifying tower II10 and the main condensation evaporator II 11; the waste nitrogen outlet at the top of the rectifying tower II10 is connected with a subcooler 17, the subcooler 17 is connected with a main heat exchanger 6, the main heat exchanger 6 is respectively connected with an external emptying pipeline and an electric heater 5, and the electric heater 5 is connected with a molecular sieve adsorber 4 which is used alternately;
the nitrogen outlet at the top of the rectifying tower II10 is connected with the main condensation evaporator II11, the liquid nitrogen outlet of the main condensation evaporator II11 is respectively connected with the liquid nitrogen pump 16, the external liquid nitrogen storage tank and the top of the rectifying tower II10, and the liquid nitrogen pump 16 is connected with the top of the rectifying tower I8.
The functions of the above components are as follows:
a filter 1 for filtering dust and mechanical impurities in the raw air;
a turbine air compressor 2 for compressing the filtered raw material air to a set pressure;
the air pre-cooling unit 3 is used for pre-cooling the filtered and compressed raw material air;
a molecular sieve adsorber 4 used alternately for purifying the filtered, compressed and precooled raw material air to remove moisture and CO2、C2H2And the like;
the electric heater 5 is used for heating the polluted nitrogen to regenerate the alternately used molecular sieve adsorber 4;
the main heat exchanger 6 is used for cooling purified raw material air and the medium-pressure nitrogen after circulating pressurization; used for reheating the pressure nitrogen and the waste nitrogen;
a low-temperature refrigerator 7 for cooling part of cooling air at the first part cooling outlet and the second part cooling outlet of the main heat exchanger 6;
a rectifying tower I8 for rectifying the raw air to separate into pressure nitrogen and liquid air;
the main condensation evaporator I9 is used for heat exchange between pressure nitrogen and liquid air, the pressure nitrogen is liquefied into liquid nitrogen, and the liquid air is vaporized into oxygen-enriched air;
the rectifying tower II10 is used for rectifying the oxygen-enriched air and the liquid air to separate the oxygen-enriched air and the liquid air into nitrogen and oxygen-enriched liquid air;
the main condensation evaporator II11 is used for heat exchange between nitrogen and oxygen-enriched liquid air, the nitrogen is liquefied into liquid nitrogen, and the oxygen-enriched liquid air is vaporized into polluted nitrogen;
the booster expansion turbine 12 is used for expanding part of cooling air at the third part cooling outlet of the main heat exchanger 6 to prepare cold energy;
the circulating nitrogen compressor 14 is used for circularly pressurizing the pressure nitrogen reheated by the main heat exchanger 6 and the nitrogen expanded by the booster turboexpander 12 and reheated by the main heat exchanger 6;
the liquid nitrogen pump 16 is used for pressurizing part of liquid nitrogen of the main condensation evaporator II 11;
and the subcooler 17 is used for liquid air subcooling and waste nitrogen gas superheating.
The preparation of the medium-pressure nitrogen by using the device comprises the following steps:
firstly, filtering raw material air by a filter 1 to remove dust and mechanical impurities, and then, introducing the raw material air into a turbine air compressor 2 to compress the air to a set pressure of 0.6-1.3 MPa; then precooled to 5-8 ℃ by an air precooling unit 3 and then purified in an alternately used molecular sieve adsorber 4 to remove moisture and CO2、C2H2And the like;
step two, the purified raw material air part is used as instrument air (not shown in the figure), the rest part enters the main heat exchanger 6, is partially cooled to 243-;
step three, separating the air into liquid air and pressure nitrogen after the air is rectified by a rectifying tower I8, wherein the pressure of the pressure nitrogen is 7-9.5 bar; liquid air is subcooled by a cooler 17 and throttled by a throttle valve and then enters a main condensation evaporator I9 to exchange heat with pressure nitrogen, the liquid air is vaporized into oxygen-enriched air, and the oxygen-enriched air and part of the liquid air which is not vaporized are introduced into the bottom of a rectifying tower II10 to participate in rectification; introducing part of pressure nitrogen into a main condensing evaporator I9 for heat exchange with liquid air, condensing the pressure nitrogen into liquid nitrogen, and introducing the liquid nitrogen into the top of a rectifying tower I8 as reflux;
step four, the oxygen-enriched air and the liquid air are rectified by a rectifying tower II10 and then are separated into oxygen-enriched liquid air and nitrogen, and the nitrogen pressure is 3-5 bar; the oxygen-enriched liquid air enters a main condensation evaporator II11 to exchange heat with nitrogen after being throttled by a throttle valve, and the oxygen-enriched liquid air is vaporized into polluted nitrogen; introducing nitrogen into a main condensation evaporator II11 for heat exchange with oxygen-enriched liquid air, condensing the nitrogen into liquid nitrogen, pressurizing part of the liquid nitrogen by a liquid nitrogen pump 16, introducing the pressurized liquid nitrogen into the top of a rectifying tower I8 for rectification, taking part of the liquid nitrogen as product liquid nitrogen, and introducing the rest of the liquid nitrogen into the top of a rectifying tower II10 for reflux;
step five, reheating the rest pressure nitrogen at the top of the rectifying tower I8 by a main heat exchanger 6, then discharging the pressure nitrogen out of a cold box, entering a circulating nitrogen compressor 14 for pressurization and cooling, wherein the cooled medium-pressure nitrogen lead-out part is used as a medium-pressure nitrogen product, the pressure of the medium-pressure nitrogen product is 20-36bar, and the purity of the medium-pressure nitrogen product is 10ppmO2The rest of the nitrogen is pressurized and cooled by the pressurizing end of the pressurizing turbo expander 12 and then enters the main heat exchanger 6, part of the nitrogen is cooled to 243-plus 252K, then introduced into the low-temperature refrigerating machine 7 and cooled to 233-plus 242K, then introduced into the main heat exchanger 6 and continuously cooled to 175-plus 186K, then the extracted part of the nitrogen enters the pressurizing turbo expander 12 for expansion, the expanded nitrogen is reheated by the main heat exchanger 6 and then enters the circulating nitrogen compressor 14 for circulation, and the rest of the nitrogen is continuously cooled until the liquefied nitrogen enters the top of the rectifying tower I8 for rectification;
and sixthly, the waste nitrogen gas led out from the top of the rectifying tower II10 is reheated by the subcooler 17 and the main heat exchanger 6 and then is discharged out of the cooling box, part of the waste nitrogen gas is used as regenerated gas and is heated by the electric heater 5 and then is led into the alternately used molecular sieve adsorber 4, and the rest of the waste nitrogen gas is discharged.

Claims (2)

1. A low-energy-consumption medium-pressure nitrogen preparation device is characterized by comprising a filter, a turbine air compressor, an air precooling unit, an alternately used molecular sieve adsorber, an electric heater, a main heat exchanger, a low-temperature refrigerator, a rectifying tower I, a main condensing evaporator I, a rectifying tower II, a main condensing evaporator II, a booster turboexpander, a booster aftercooler of the booster turboexpander, a circulating nitrogen compressor aftercooler, a liquid nitrogen pump and a subcooler,
the device comprises a filter, a turbine air compressor, an air precooling unit, an alternately used molecular sieve adsorber, an electric heater, a low-temperature refrigerator, a supercharging end of a supercharging turboexpander, a supercharging aftercooler of the supercharging turboexpander, a circulating nitrogen compressor and an aftercooler of the circulating nitrogen compressor, which are arranged outside a cold box, a main heat exchanger, a rectifying tower I, a main condensing evaporator I, a rectifying tower II, a main condensing evaporator II, the supercharging turboexpander, a liquid nitrogen pump and a subcooler are arranged in the cold box, the main condensing evaporator I is arranged on the rectifying tower I, and the main condensing evaporator II is arranged on the rectifying tower II;
the device comprises a filter, a turbine air compressor, an air precooling unit, an alternately used molecular sieve adsorber and a main heat exchanger which are sequentially connected, wherein a first part cooling outlet of the main heat exchanger is connected with a low-temperature refrigerator, the low-temperature refrigerator is connected with the main heat exchanger, and a first complete cooling outlet of the main heat exchanger is connected with a raw material air inlet at the bottom of a rectifying tower I;
a liquid-air outlet at the bottom of the rectifying tower I is connected with a subcooler, the subcooler is connected with a main condensing evaporator I, a throttle valve is arranged on a connecting pipeline of the subcooler and the main condensing evaporator I, and an oxygen-enriched air outlet of the main condensing evaporator I and a liquid-air outlet of the main condensing evaporator I are both connected with the bottom of a rectifying tower II;
a pressure nitrogen outlet at the top of the rectifying tower I is respectively connected with the main condensation evaporator I and the main heat exchanger, and a liquid nitrogen outlet of the main condensation evaporator I is connected with the top of the rectifying tower I; the main heat exchanger is connected with the circulating nitrogen press, the circulating nitrogen press is connected with a rear cooler of the circulating nitrogen press, the rear cooler of the circulating nitrogen press is respectively connected with an external medium-pressure nitrogen storage tank and a boosting end of a boosting turboexpander, the boosting end of the boosting turboexpander is connected with the boosting rear cooler of the boosting turboexpander, the boosting rear cooler of the boosting turboexpander is connected with the main heat exchanger, a second part cooling outlet of the main heat exchanger is connected with a low-temperature refrigerator, the low-temperature refrigerator is connected with the main heat exchanger, a third part cooling outlet and a second complete cooling outlet of the main heat exchanger are respectively connected with the boosting turboexpander and the top of a rectifying tower I, the boosting turboexpander is connected with the main heat exchanger, and the main heat exchanger is connected with the circulating nitrogen press; a throttle valve is arranged on a connecting pipeline between a second complete cooling outlet of the main heat exchanger and the top of the rectifying tower I;
an oxygen-rich liquid air outlet at the bottom of the rectifying tower II is connected with the main condensation evaporator II, and a throttle valve is arranged on a connecting pipeline between the oxygen-rich liquid air outlet at the bottom of the rectifying tower II and the main condensation evaporator II; the waste nitrogen outlet at the top of the rectifying tower II is connected with a subcooler, the subcooler is connected with a main heat exchanger, the main heat exchanger is respectively connected with an external emptying pipeline and an electric heater, and the electric heater is connected with a molecular sieve adsorber which is used alternately;
the nitrogen outlet at the top of the rectifying tower II is connected with the main condensation evaporator II, the liquid nitrogen outlet of the main condensation evaporator II is respectively connected with the liquid nitrogen pump, the external liquid nitrogen storage tank and the top of the rectifying tower II, and the liquid nitrogen pump is connected with the top of the rectifying tower I.
2. The low energy consumption medium pressure nitrogen gas production plant as claimed in claim 1, wherein the pressure of the medium pressure nitrogen gas product produced by the plant is 20-36bar, and the purity is 10ppmO2The following.
CN202020125895.2U 2020-01-19 2020-01-19 Low-energy-consumption medium-pressure nitrogen preparation device Active CN211451560U (en)

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