阅读说明：本技术 一种基于深冷精馏工艺生产空气产品的方法及空分系统 (Method for producing air product based on cryogenic rectification process and air separation system ) 是由 赵伯伟 布里格利亚·阿兰 薛凤杰 于 2017-12-28 设计创作，主要内容包括：一种基于深冷精馏工艺生产空气产品的方法及空分系统,在现有的深冷精馏工艺设备中增设空气产品导出管路(113)及液空增压泵(1131),利用现有精馏设备制备富氧液空,将原料空气增压、降温液化,还可根据客户需求,调配原料空气与富氧液空的比例,经液空增压泵(1131)增压至目标压力,经换热设备与精馏产生的气体或液体产品换热汽化后,制备高压或超高压的空气产品。在精馏生产氧、氮气体或液体产品的同时,可根据客户需求提供高压或超高压的空气产品,且无需设置额外的空气压缩机或被动地提高空气增压机的排压,极大地降低了生产成本,提高了能效水平。尤其是在需要生产少量的高压/超高压空气产品时,还可提高装置的稳定性。(A method for producing air products based on cryogenic rectification technology and an air separation system are characterized in that an air product leading-out pipeline (113) and a liquid air booster pump (1131) are additionally arranged in existing cryogenic rectification technology equipment, oxygen-enriched liquid air is prepared by utilizing the existing rectification equipment, raw material air is pressurized, cooled and liquefied, the proportion of the raw material air and the oxygen-enriched liquid air can be adjusted according to customer requirements, the raw material air is pressurized to a target pressure by the liquid air booster pump (1131), and high-pressure or ultrahigh-pressure air products are prepared after heat exchange and vaporization are carried out on gas or liquid products generated by rectification through heat exchange equipment. When oxygen, nitrogen gas or liquid product are produced by rectification, high-pressure or ultrahigh-pressure air products can be provided according to customer requirements, and an additional air compressor or the pressure discharge of an air supercharger is not required to be arranged, so that the production cost is greatly reduced, and the energy efficiency level is improved. Especially when a small amount of high/ultra high pressure air product needs to be produced, the stability of the device can be improved.)

A method for producing an air product based on a cryogenic rectification process, comprising:

(a) an air separation system for producing a nitrogen product and/or an oxygen product is provided, comprising: the system comprises a rectifying tower, at least one air pressurization system, at least one air precooling device, at least one air purifying device and at least one heat exchange device, wherein the rectifying tower comprises a first tower with a first pressure, a second tower with a second pressure and a main condensation evaporation device arranged at the bottom of the second tower; the air pressurization system comprises a main air compressor and at least one air supercharger;

(b) raw material air is sequentially pressurized to a first pressure range through a main air compressor, precooled by an air precooling device, purified by an air purifying device, divided into a part serving as a first air flow strand, and subjected to heat exchange with a gas or liquid product generated by rectification through a heat exchange device, and then introduced into a first tower for rectification after being cooled; the other part of the air is pressurized to a third pressure range through an air supercharger, a second air stream and a third air stream are separated, the second air stream exchanges heat with gas or liquid products generated by rectification through heat exchange equipment, is guided out from the middle part of the heat exchange equipment, is depressurized to the first pressure range through an air expander and is guided into a first tower for rectification; the third air flow is subjected to heat exchange with gas or liquid products generated by rectification through heat exchange equipment, and after cooling, the third air flow is depressurized to a first pressure range and then introduced into the first tower or depressurized to a second pressure range and then introduced into the second tower;

(c) providing a liquid nitrogen pipeline and an oxygen-enriched liquid air pipeline, respectively introducing liquid nitrogen at the top of the first tower and oxygen-enriched liquid air at the bottom of the first tower into the second tower to be used as reflux liquid, and rectifying;

characterized in that the method further comprises:

providing an air product leading-out pipeline, arranging at least one liquid air booster pump on the air product leading-out pipeline, leading out oxygen-enriched liquid air or at least partially liquefied raw material air from a third air stream from the bottom of the first tower through the air product leading-out pipeline, boosting the raw material air to a target pressure through the liquid air booster pump, and then performing heat exchange vaporization through heat exchange equipment to obtain a required air product.

The method of claim 1, wherein the air expander is actuated by an expansion compressor, and the third air stream is pressurized to a fourth pressure range by the expansion compressor, enters a heat exchange device to exchange heat with the gas or liquid product produced by the rectification, is cooled, is depressurized to a first pressure range by a depressurization device, and is introduced into the first column.

The method for producing an air product based on a cryogenic rectification process of claim 2 wherein the pressure reduction device is a throttling valve or a liquid expander.

The method of producing an air product based on a cryogenic rectification process of claim 3 wherein the liquid expander is braked by an electric generator.

The method for producing an air product based on a cryogenic rectification process of claim 2 wherein the third air stream reduced in pressure to the first pressure range is further divided into a fourth air stream that is throttled down by a throttle valve to a second pressure range and directed to the second column.

The method for producing an air product based on cryogenic rectification process of claim 5, wherein the fourth air stream is further divided into a fifth air stream, the fifth air stream is communicated with the air product outlet pipeline, and the flow rate and the flow velocity of the fifth air stream are controlled by the first regulating valve.

The method for producing an air product based on cryogenic rectification process of claim 1 or 6, wherein a second regulating valve is further provided in the air product outlet line to control the flow rate of the oxygen-enriched liquid air.

The method for producing an air product based on a cryogenic rectification process of claim 1 wherein the heat exchange apparatus comprises a low pressure plate heat exchanger and a high pressure plate heat exchanger or an integral combination heat exchanger.

The method of producing an air product based on a cryogenic rectification process of claim 8 wherein the heat exchange apparatus further comprises a subcooler through which reflux liquid entering the second column exchanges heat with the gas or liquid product being rectified by the second column.

The method of producing an air product based on a cryogenic rectification process of claim 1, further comprising: the waste liquid nitrogen is extracted from the first column and introduced into the second column as a reflux liquid.

The method of producing an air product based on a cryogenic rectification process of claim 1, further comprising: liquid oxygen is extracted from the main condensation evaporation equipment, is pressurized to the required pressure by a liquid oxygen booster pump, and is subjected to heat exchange and vaporization by heat exchange equipment to prepare an oxygen product.

The method of producing an air product based on a cryogenic rectification process of claim 1, further comprising: extracting liquid nitrogen from the top of the first tower, and directly carrying out heat exchange vaporization through heat exchange equipment to prepare a first nitrogen product; or pumping liquid nitrogen from the top of the first tower, pressurizing the liquid nitrogen to a required pressure by a liquid nitrogen booster pump, and then carrying out heat exchange vaporization by heat exchange equipment to prepare a second nitrogen product.

The method of producing an air product based on a cryogenic rectification process of claim 1, further comprising: pumping ultra-low pressure nitrogen from the top of the second tower, and reheating by heat exchange equipment to prepare a third nitrogen product.

The method of producing an air product based on a cryogenic rectification process of claim 1, further comprising: and pumping the waste nitrogen from the upper part of the second tower, and reheating the waste nitrogen by using heat exchange equipment to obtain a waste nitrogen product.

An air separation system for producing an air product based on a cryogenic rectification process, the air separation system comprising:

(a) the rectifying tower comprises a first tower with a first pressure, a second tower with a second pressure and a main condensation and evaporation device arranged at the bottom of the second tower; a liquid nitrogen pipeline which guides liquid nitrogen at the top of the first tower into the second tower through a throttle valve and an oxygen-enriched liquid air pipeline which guides oxygen-enriched liquid air at the bottom of the first tower into the second tower through the throttle valve are arranged between the first tower and the second tower;

(b) the system comprises at least one air pressurization system, at least one air pre-cooling device, at least one air purification device, at least one heat exchange device, at least one air expander, at least one liquid oxygen booster pump, at least one liquid air booster pump and a plurality of pressure reduction devices; the air pressurization system comprises a main air compressor and at least one air supercharger;

(c) introducing raw material air into a first air input pipeline of a first tower through a main air compressor, an air precooling device, an air purifying device and a heat exchange device; leading out raw material air from the middle of a main air compressor, an air precooling device, an air purifying device and a self-heat exchange device, and leading the raw material air into a second air input pipeline of the first tower through an air expander; the second air input pipeline is also provided with a third air input pipeline before entering the heat exchange equipment, and the third air input pipeline directly passes through the heat exchange equipment and is communicated with the first tower or the second tower through a pressure reduction device;

(d) leading out liquid oxygen product from the main condensing and evaporating equipment through at least one liquid oxygen booster pump and then through a heat exchange equipment;

it is characterized by also comprising: and the air product leading-out pipeline is communicated with the bottom of the first tower or a third air input pipeline, and at least one liquid-air booster pump is arranged on the air product leading-out pipeline and is used for boosting at least part of liquefied raw material air from the third air input pipeline or oxygen-enriched liquid air led out from the bottom of the first tower to a target pressure, and the air product is subjected to heat exchange vaporization through heat exchange equipment to output a required air product.

An air separation system for producing an air product based on cryogenic rectification according to claim 15 wherein the air expander is actuated by an expansion booster and the third air inlet line is connected to the first column via the expansion booster, the heat exchange means and the pressure reduction means.

An air separation system for producing an air product based on a cryogenic rectification process according to claim 16 further comprising a fourth air input line leading from a third air input line communicating between the pressure reduction device and the first column and to the second column via the throttle valve.

An air separation system for producing an air product based on a cryogenic rectification process as claimed in claim 17 wherein the pressure reduction device is selected from a throttling valve or a liquid expander.

An air separation system for producing an air product based on cryogenic rectification process as claimed in claim 17 wherein the fourth air input line is further provided with a fifth air input line, and the fifth air input line is communicated with the air product outlet line, and is led out through the liquid air booster pump and the heat exchange device to output the required air product.

The air separation system for producing an air product based on the cryogenic rectification process of claim 19 wherein the fifth air input line further includes a first regulating valve for controlling the flow rate and velocity of the air stream.

An air separation system for producing an air product based on a cryogenic rectification process as claimed in claim 15 or claim 20 wherein the air product delivery line is further provided with a second regulating valve for controlling the flow rate of the oxygen-enriched liquid air.

An air separation system for producing an air product based on a cryogenic rectification process as claimed in claim 15 further comprising: a first nitrogen product outlet pipeline for carrying out heat exchange vaporization on the liquid nitrogen at the top of the first tower through heat exchange equipment to prepare a first nitrogen product; or, at least one liquid nitrogen booster pump, and a second nitrogen product leading-out pipeline for preparing a second nitrogen product, wherein the liquid nitrogen pumped out from the top of the first tower is pressurized to the required pressure by the at least one liquid nitrogen booster pump, and then is subjected to heat exchange vaporization by heat exchange equipment; or a third nitrogen product outlet pipeline which leads out the nitrogen at the top of the second tower through the heat exchange equipment.

An air separation system for producing an air product based on a cryogenic rectification process according to claim 15 or claim 22 wherein a dirty liquid nitrogen line is provided between the first column and the second column that directs dirty liquid nitrogen from the first column to the second column via the throttle valve.

An air separation system for producing an air product based on a cryogenic rectification process according to claim 23 further comprising a waste nitrogen line that directs waste nitrogen from the second column through the heat exchange means.

An air separation system for producing an air product based on a cryogenic rectification process as claimed in claim 15 wherein the heat exchange means comprises a high pressure plate heat exchanger and a low pressure plate heat exchanger or an integral combination heat exchanger.

An air separation system for producing an air product based on a cryogenic rectification process as claimed in claim 25 wherein the heat exchange means further comprises a subcooler for exchanging heat between the reflux liquid entering the second column and the rectified gas or liquid product from the second column.