Full liquid-product air separation equipment and process therefor

Abstract

A full liquid-product air separation equipment is disclosed. The equipment comprises an air filtration system, a compression system, a precooling system, a purification system, a high-temperature expander having a first pressurizing part and a first expanding part, a low-temperature expander having a second pressurizing part and a second expanding part, a main heat exchanger having a first heat exchange pipeline, a second heat exchange pipeline, a third heat exchange pipeline, a fourth heat exchange pipeline and a fifth heat exchange pipeline, and a rectification system for rectifying air. The equipment has a simple configuration, is easy to implement, and has high gas separation efficiency and low energy consumption.

What is claimed is: 
     
         1 . A full liquid-product air separation equipment comprising:
 an air filtration system;   a compression system;   a precooling system;   a purification system;   a high-temperature expander, having a first pressurizing part and a first expanding part;   a low-temperature expander, having a second pressurizing part and a second expanding part;   a main heat exchanger, having a first heat exchange pipeline, a second heat exchange pipeline, a third heat exchange pipeline, a fourth heat exchange pipeline and a fifth heat exchange pipeline; and   a rectification system for rectifying air;   wherein the air filtration system, the compression system, the precooling system, and the purification system are connected sequentially and then connected to the first pressurizing part, and the first pressurizing part is connected to the second pressurizing part connected to the first heat exchange pipeline;   the first heat exchange pipeline comprises a main pipeline connected to the second pressurizing part and two first branches connected to the main pipeline, one of the two first branches is connected to the second expanding part and the other of the two first branches is connected to the rectification system;   the second expanding part is connected to the second heat exchange pipeline and the rectification system, respectively, a waste nitrogen pipeline connected to the rectification system for extracting a stream of pressure waste nitrogen is connected to the second heat exchange pipeline, the second exchange pipeline is connected to the first expanding part, and the first expanding part is connected to the third heat exchange pipeline;   the third heat exchange pipeline has two second branches, one of the two second branches is connected to the purification system to provide adsorbent regeneration gas, and the other of the two branches is connected to the precooling system; and   the rectification system has a low-pressure waste nitrogen outlet connected to the fourth heat exchange pipeline, and the low-pressure nitrogen outlet is connected to the fifth heat exchange pipeline, and the fourth and fifth heat exchange pipelines are both connected to the precooling system.   
     
     
         2 . A process for full liquid-product air separation, using the full liquid-product air separation equipment according to  claim 1 , comprising:
 filtering, compressing, precooling and purifying air to remove water and carbon dioxide into purified and compressed air with a pressure of 10-60 bar and a temperature of 5-50° C.;   continuously pressurizing the purified and compressed air through the first pressurizing part of the high-temperature expander and the second pressurizing part of the low-temperature expander, then exchanging heat in the first heat exchange pipeline of the main heat exchanger, extracting a part of the air in the first heat exchange pipeline in a middle portion thereof and expanding in the second expanding part of the low-temperature expander, and making a high-pressure liquid air formed by the other part of the air at a bottom of the main heat exchanger enter the rectification system after throttling;   dividing the air expanded by the second expanding part into two parts to enter the second heat exchange pipeline of the main heat exchanger and the rectification system for distillation, respectively;   extracting a stream of pressure waste nitrogen from the rectification system to merge into the second heat exchange pipeline, mixing the waste nitrogen and exchanging heat through the second heat exchange pipeline, and then expanding it in the first expanding part of the high-temperature expander into a low-pressure waste nitrogen, reheating the low-pressure waste nitrogen through the third heat exchange pipeline of the main heat exchanger into a low-pressure room-temperature waste nitrogen;   a part of the low-pressure room-temperature waste nitrogen entering the purification system to provide an adsorbent regeneration gas for the purification system, and the other part of the low-pressure room-temperature waste nitrogen entering the precooling system to produce chilled water;   separating and liquidizing the air entering the rectification system to produce liquid nitrogen, liquid oxygen and liquid argon;   reheating the low-pressure waste nitrogen generated by the rectification system through the fourth heat exchange pipeline of the main heat exchanger, reheating the low-pressure nitrogen generated by the rectification system through the fifth heat exchange pipeline of the main heat exchanger; and   letting the waste nitrogen reheated through the fourth heat exchange pipeline and the nitrogen reheated through the fifth heat exchange pipeline both enter the precooling system to produce chilled water.   
     
     
         3 . A process for full liquid-product air separation, using the full liquid-product air separation equipment according to  claim 1 , comprising:
 filtering, compressing, precooling and purifying air;   continuously pressurizing the air through the first pressurizing part of the high-temperature expander and the second pressurizing part of the low-temperature expander, then exchanging heat in the first heat exchange pipeline of the main heat exchanger, extracting a part of the air in the first heat exchange pipeline in a middle portion thereof and expanding in the second expanding part of the low-temperature expander, and making a high-pressure liquid air formed by the other part of the air at a bottom of the main heat exchanger enter the rectification system;   dividing the air expanded by the second expanding part into two parts to enter the second heat exchange pipeline of the main heat exchanger and the rectification system for distillation, respectively;   extracting a stream of pressure waste nitrogen from the rectification system to merge into the second heat exchange pipeline, mixing the waste nitrogen and exchanging heat through the second heat exchange pipeline, and then expanding it in the first expanding part of the high-temperature expander into a low-pressure waste nitrogen, reheating the low-pressure waste nitrogen through the third heat exchange pipeline of the main heat exchanger into a low-pressure room-temperature waste nitrogen;   a part of the low-pressure room-temperature waste nitrogen entering the purification system to provide an adsorbent regeneration gas for the purification system, and the other part of the low-pressure room-temperature waste nitrogen entering the precooling system;   reheating the low-pressure waste nitrogen generated by the rectification system through the fourth heat exchange pipeline of the main heat exchanger, reheating the low-pressure nitrogen generated by the rectification system through the fifth heat exchange pipeline of the main heat exchanger; and   letting the waste nitrogen reheated through the fourth heat exchange pipeline and the nitrogen reheated through the fifth heat exchange pipeline both enter the precooling system.   
     
     
         4 . The process for full liquid-product air separation according to  claim 3 , wherein the air is filtered, compressed, precooled, and purified to remove water and carbon dioxide into purified and compressed air with a pressure of 10-60 bar and a temperature of 5-50° C. 
     
     
         5 . The process for full liquid-product air separation according to  claim 3 , wherein the high-pressure liquid air enters the rectification system after throttling. 
     
     
         6 . The process for full liquid-product air separation according to  claim 3 , wherein the air entering in the rectification system is separated and liquidized to obtain liquid nitrogen, liquid oxygen and liquid argon.