SU1663350A1 - Air separation unit - Google Patents

Abstract

This invention relates to a cryogenic technique. The aim of the invention is to increase the yield of pure air separation products. The air separation unit is characterized by the fact that a jet apparatus is installed parallel to the expander, the inlet of which is connected to the high pressure air pipeline after the main heat exchanger. 3 il.

Description

This invention relates to a cryogenic technique.

The aim of the invention is to increase the yield of pure air separation products.

FIG. 1 shows an air separation unit; in fig. 2 is an apparatus with a liquid separator entering the air separation unit; in fig. 3 - pipe input gas pipeline into a distillation column.

The installation includes a compressor 1 for compressing air, a pre-heat exchanger 2, an air purification unit 3 for moisture, carbon dioxide and hydrocarbons, a main heat exchanger 4, a cooler 5, an expander 6, a distillation column 7, a compressed air condenser 8, an apparatus 9 with a liquid separator, an evaporator condenser 10, nitrogen heat exchanger 11, nitrogen throttle valve 12, nitrogen compressor 13, argon heat exchanger 14, end heat exchanger 15, inlet pipe 16 for supplying compressed air, 17 Laval nozzles, chamber 18 with distributor 19 fluid, diffuser 20, liquid separator 21, liquid pipe 22, gas pipe 23, body 24 columns 7, distillation plates 25, partition 26, support 27.

The installation works as follows.

Compressor 1 compresses the air to a pressure of 5-9 MPa, then the air is cooled in the preliminary heat exchanger 2, cleaned of moisture, carbon dioxide and hydrocarbons in the apparatus 3, cooled in the heat exchanger with nitrogen vapor, cooled in the cooler 5 by external coolant and fed to the heat exchanger 4.

The air is then divided into two parallel streams: the main stream in an amount of at least 80% is fed to the expander 6, where the air expands adiabatically to intermediate pressure, thereby forming liquid air. In the condenser 8, the remaining gaseous air is liquefied at the RP, and liquid air is collected in the lower part of the condenser 8.

The second stream of compressed air in an amount of not more than 20% is fed into the apparatus 9.

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The flow of compressed air passes through the pipe 16, adiabatically expands in the nozzle 17 Laval with the achievement of the number at the nozzle section. Liquid air is supplied through the pipe of the liquid distributor 19 through the heat exchanger 14 from the condenser 8 into the mixing chamber 18. The passage through the holes in the inner tube of the mixing chamber, the liquid is choked into a stream of cold expanded air, after which the mixture is directed into the diffuser 20, the liquid air is separated in the liquid separator 21 and fed into the upper part of the column 7 to the distillation plates 25, flows down, providing implementation of the rectification process.

The non-liquefied air through the pipe 23 is withdrawn from the liquid separator 21 and is introduced through the pipe through the wall of the housing 24 into the column 7, into the gap between the rectification plates. The air flow flows over the partition 26 and passes through the gap into the space between the plates 25, where it is braked. Thus, an additional amount of heat is introduced into the column, which contributes to additional boiling of nitrogen from the reflux column 7 flowing down over the overlying plates 25. This increases the yield of pure products. The flowing liquid is enriched with oxygen, after which it flows into the lower part of the column 7, where the evaporation is provided by the heat of condensation of the compressed air in the condenser 8. Liquid oxygen from the bottom of the column 7 is divided into two streams: one is sent to the heat exchanger 15, where it is heated to the environmental parameters and given as a gas to the consumer; the other stream is sent to the evaporator-condenser 10, where residual nitrogen is evaporated from the liquid, after which liquid oxygen is supplied to the heat exchanger 11, cooled and supplied to the consumer,

Nitrogen from column 7 is passed through heat exchanger 11 and divided into two streams. Most of the flow is heated in cooler 4 and pre-heat exchanger 2, a smaller part is sent to heat exchanger 15, after which the streams are mixed and sent to compressor 13 to compress nitrogen. Nitrogen is compressed in the compressor

13 to pressure and divided into two streams. A part of the stream is delivered to the consumer in the form of compressed gas, the main stream — circulating nitrogen — is directed to the heat exchanger 15 for cooling, and is condensed into

evaporator condenser 10, liquid nitrogen is cooled in heat exchanger 11, expanded in nitrogen throttle valve 12, and liquid nitrogen is fed to the top plate of column 7 as reflux.

The nitrogen fraction is taken from the middle part of the distillation column 7, heated in heat exchangers 14 and 15, and either used in the apparatus 3 for the regeneration of absorbers, or released into the atmosphere.

The proposed installation allows to increase the yield of pure separation products of air up to 5%,

Claims (1)

Formula of gain An air separation unit comprising a manifold with a sequentially installed compressor, an air cooler, an air purification apparatus for moisture, carbon dioxide and hydrocarbons, a main heat exchanger, an expander and a single rectification column, as well as a nitrogen compressor and a nitrogen throttle valve, characterized in that In order to increase the yield of pure separation products, the installation additionally contains a Lawal nozzle, a mixing chamber with a liquid distributor, a diffuser and a liquid separator with a liquid and g zovym nozzles sequentially connected to the line between the main heat exchanger and the expander, the liquid distributor is connected to the bottom of the column, the liquid pipe of the liquid separator to the top of the column, the gas pipe to the middle of the column and in the place where the latter is connected, there is a partition perpendicular to the axis of the pipe in the column. FIG. 23 ,, t Wbvt vfn t L 77 sixteen 2 2B / Y