JPS58138974A - Method of separating air - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] What is the invention? Regarding the method of separating static electricity by liquefying it, in particular, it is possible to separate static electricity using an all-low pressure method to achieve low purity (approximately 95 #lN).
) relates to a method for economically producing oxygen.

N2 *02-A by liquefying air and rectifying it
The air liquefaction/splitting device 1IFi is in operation in the field of bridges. In this shelf air liquefaction separation equipment, it is necessary to apply pressure and pressure shock to the raw material static electricity and product oxygen according to the operating conditions, so a compressor is used.

The transmission of waves from equipment such as clinics is essential. In addition, since many of the air conditioning units were manufactured by Yoshi Otani and the power costs were high,
l! To reduce the manufacturing cost of bulk I acid, M'JfIJ
It is necessary to reduce such power costs as much as possible by improving efficiency. In addition to this, there is a similar but effective solution for low-purity enzyme heavy packaging using a so-called all-low-pressure air bulking system (hereinafter simply referred to as "oxygen stocking").
#t is hardly taken.

Ito's first production method for low-purity oxygen using completely low-pressure electrostatic separation (
(hereinafter referred to as “oxygen preparation method”) is generally referred to as @I W
It is carried out according to the thread diagram shown in Figure 1. That is, raw air is supplied from the air filter 1, pressurized to about 4.6 ata by the 7p pressure tightening filter 2, and then passed through the aftercooler 8.
cooled down. Next, it enters the I'11 inverse heat exchanger 4 through the pipe 21, exchanges heat with the Q product and impure nitrogen, and is cooled almost to its boiling point. History V Route 22 to Yurushima Low Pressure Tower C
(hereinafter simply referred to as the "upper tower") 5 is introduced into a 5 gl condenser 6 at the bottom of the upper tower 5, where it is supercooled to below the nodal point by heat exchange with m flowing liquid from the upper tower 5. Therefore, some of it liquefies. The air is then introduced into the gas-liquid separator 7 through the pipe 23 and separated into gaseous air and liquid air.

Liquid air is all iliMv! The M column is led to an intermediate pressure column (hereinafter referred to simply as the "lower column") 8. In this way, the nine liquid static electricity introduced into the lower column 8 vaporizes and becomes a rising gas, while it is brought into contact with the reflux liquid (nitrogen-rich liquid) obtained by condensation at the top of the lower column 8, and is crudely distilled. At the top of the lower column 8, nitrogen-rich gas is passed, and at the bottom of the lower column 8, the jllfJt liquid becomes a liquid static with an oxygen content of about 80 to 40%. On the other hand, the gaseous air separated in the gas-liquid separator 7 is completely liquefied while passing through the fitting device 9 from the pipe 24, and then is liquefied in the pipe 25. Liquid air supercooler 10
．． It is led to the upper part of the upper tower 5 through a pipe 26.

In addition, the liquid air that has been coarsely distilled as described above in the lower tower 8 is transferred to the pipe line 2.
8 into the liquid air subcooler lO. After being cooled, the line 29. The expansion valve 11 leads to the @2 condenser 2 installed at the top of the lower column 8, and the condenser 12 leads to the lower column 8.
The solid air is gasified by heat exchange with Tominitoshi gas inside. The resulting gaseous air enters the expander 18 through the nv line f'IO, 81, where it is led to the upper tower 5 through the pipe 82 where it is cooled. On the other hand, the nitrogen 3 stored at the top of the lower tower 8 is introduced into the liquid air supercooling leg unit ld through the passage 88.
The cooled reconnaissance vessel is led to the upper part of the upper tower 5 from V 84.

At Upper Tower 5! The low-purity aqueous solution that has been distilled and stored at the bottom is extracted from the lowermost end of the bottom of the upper column 5 and led to the admixture reactor 1R through the V line 85.

The low-purity nitrogen-rich gas, which has been slightly recovered in the wetland area, is introduced into the reversible heat exchanger 4 through the pipe 86i7, and its temperature is greatly recovered in the heat exchanger 4.

Next! It is recovered as product oxygen to the outside through line 37.

By the way, in the Yame bending method as shown in the upper part 1, the lower tower 8
The pressure of the distilled logical nitrogen (approximately 4.8 ata) is reduced to approximately 2.2 ata by the expansion valve 11, and then reduced to approximately 1.2 to 1.8 ata by the expansion valve 18 (so-called Because the low-pressure turbine system generates friction for cold storage in the process, the drive efficiency of one AHARI AL unit is not very good.Therefore, the necessary and sufficient amount of refrigeration is In order to obtain KFi expansion [11B's t!
Liquid air 9 rectified in the lower tower 8! c is an expansion valve 11. After passing through the expander 1B, all of the gas rises in the upper tower 5, so the total reflux f& in the upper tower 5 is in a state of absolute shortage 6. Due to this absolute shortage of reflux liquid, the separation efficiency of oxygen components and nitrogen and snow waste in the upper column 6 was naturally limited, and therefore there was a limit to the rectification efficiency. Amid such rising power costs, the limitations of rectification efficiency remained the rate-limiting factor in reducing the production cost of product oxygen.

The present invention was made in view of these circumstances, and its purpose is to increase the drive efficiency of the expander to reduce power costs, and to reduce the amount of oxygen and crab components in the upper column by reducing the reflux liquid. The aim is to compensate for the decrease in separation efficiency and increase the rectification efficiency, thereby reducing the production cost of the oxygen product.

However, the air separation method of the present invention, which has achieved these objectives, involves partially liquefying the raw material air in the @l condenser at the bottom of the upper tower, atomizing the raw material air into gaseous air and liquid air, and separating the Body air is l! At the same time, the gas static electricity is divided into two parts and one side is applied to an expander to lower the pressure and generate refrigeration, and then introduced into the upper tower to reduce the rising gas in the upper tower. and the other is introduced into the lower tower and used as the rising gas of the lower tower, before! By exchanging heat with the mixed fluid extracted from the middle part of the upper tower, the high nitrogen gas obtained in the lower tower IJII is cooled and liquefied to liquefy the Tomiya gas, which is then discharged from the upper part of the upper tower.
The main point is that the mixed fluid is evaporated into a gas and returned to the upper tower to form a rising gas at the top.

The paulownia bottom and the effects of the present invention will be explained below based on the drawings of this embodiment, but the lower embodiment is merely a representative example, and the history will be explained as appropriate in accordance with the spirit of the above and below. 4 It is impossible to give alms until you commit a crime.

Figure 2 shows a system diagram of the all-low-pressure air separation method of the present invention.The basic 11 air separation methods are the same as those of the conventional example in Figure 1, and those with the same configuration are given the same symbols. I will omit the explanation 3
The following description will focus on the configuration that characterizes this embodiment.

The feed air partially liquefied in the @1 condenser 6 at the bottom of the upper tower 50 is separated into gas-liquid into gaseous air and liquid static electricity in the separator 7. This gaseous air is divided into two parts, and the flow rate ratio to the raw material air is 80% (pressure: 4.8 to 4.4).
aha) is directly introduced into the expander 18 through the pipe 24', Ill, and reduced in pressure to 1.2 to 1 Jata[1], and after generating refrigeration, is introduced into the upper tower through the pipe 82.

In this alK WM example, the cold generation is performed by a so-called high-pressure turbine system, so the amount of cold generation per expander is large. Therefore, the drive efficiency of the w expansion machine 18 is improved, and its differential cost is can be saved.

Also in this example, the raw air other than the above gaseous air is
All of the liquid is introduced into the upper column 6 and used as a reflux liquid. That is, the liquid air generated in the gas-liquid separator 7 is further transferred to the liquid air supercooler lO.
After cooling, it is introduced into the upper tower 6 through conduit IC. Further, the entire amount of the gaseous air generated in the gas-liquid separator 7 is introduced into the lower column 8, excluding the gaseous air for generating cold as described above, to provide liquid air at the bottom and sK voluminous gas at the top. And liquid air is
After being introduced into the liquid air supercooler 1G through the pipe 28 and cooled, it is introduced into the upper tower 5 through the pipe 2F', while the nitric acid gas is introduced into the heat exchanger 14 through the pipe 42, and the Heat exchange-14 Heat exchange with the oxygen and nitrogen component mixed fluid extracted from the middle part of the donation tower 6 to cool and liquefy W! Kn rich nitrogen s
f& is introduced into the liquid air supercooler 10 through the line 48.
After cooling, it is introduced into the upper tower 5 through a pipe 84. Therefore, the overall flow rate of tN# in the upper column 5 is the same as in the conventional example, but the rectification @gravity of the upper column 5 is thicker (different. In the exchanger 14, as described above (while the conduit 42 liquefies the DUSC nitrogen gas, it also simultaneously gasifies the nitrogen component of the oxygen and nitrogen component mixed fluid from the conduit 4B). The mixed fluid containing the nine nitrogen gas components obtained by
The separation of oxygen and nitrogen in the upper column 5 is promoted to the extent that the nitrogen component is gasified in step 4, and the rectification efficiency is increased.

The air separation method of the present invention is roughly configured as described above,
In short, the gauze column is driven by a so-called high-pressure turbine system, and the lack of rectification caused by the absolute lack of reflux liquid is compensated for by adding an IIG gasification promotion means, which increases the drive efficiency of the expander and increases the power output. In order to save costs, it has become possible to produce low-purity product oxygen more economically by increasing the rectification efficiency.

In addition, by reducing the power required to operate the air separation method, so-called energy conversion can be achieved, so in today's world where there is a strong demand for saving energy, the industry can play a large role in this aspect. .

[Brief explanation of the drawing]

Figure 1 is a systematic diagram of the conventional #t1# life method, and the second cause is the #I of the present invention! It is a 'lk system diagram illustrating the lit construction method. 4...Reversible heat exchanger 5...Low pressure column 6...@1
Condenser 7... Gas-liquid separator 8... Medium pressure column
9...Liquifier lO...Liquid pneumatic supercooler 12-・Second condenser? 18... Expander U...
Heat exchanger

Claims (1)

[Claims] (1) Raw material '4 which was compressed by pressure w3 machine and cooled by heat exchanger! The gas is led to the first condenser at the bottom of the low pressure column, where it exchanges heat with the liquid # element in the low pressure column, and the quasi-form I!
Ilftgtl-# Boil the IM feed air as it becomes the rising gas of the low-pressure column, subcool it to IMJf below Q to partially liquefy, and bring the rising gas into contact with the recirculating liquid from the upper part of the low-pressure column. As a result, the low duty tower bottom is converted into a concentrated liquid from the recycled fM liquid stored in the city, while the throated air is introduced into the medium pressure column and vaporized to produce the rising gas of the medium pressure column. The medium pressure i% top of the head is brought into contact with the reflux liquid discharged by the second condenser, and the handle is fixed, and the Tomimuro gas is turned off at the medium pressure jil collapse part, and the above Jl! In an air separation method in which the flowing liquid becomes liquid static at the bottom of the medium-pressure column, the raw static electricity, which is partially liquefied, is separated into gaseous air and liquid air in the first condenser at the bottom of the low-pressure field. 9 tons of liquid air is further cooled and introduced into the upper part of the low-pressure column to form a liquid, while the gas air '*c is divided into two parts and one side is applied to an expander to lower the pressure and generate cooling. , the nitrogen-rich gas obtained in the above-mentioned Nakashito-Koto is introduced into the low-pressure column to serve as the rising gas of the low-pressure column, and the other is introduced into the middle a-tube to serve as the rising gas of the medium-pressure column. The nitrogen-rich gas is cooled and liquefied by exchanging heat with the mixed fluid of oxygen and nitrogen components extracted from the middle part of the column to form a reflux liquid from the upper part of the low-pressure column, while the mixed fluid is spontaneously gasified and added to the low-pressure column. 41i?
Air separation method.