JPS63197870A - air separation equipment - 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] [Industrial application field] The present invention relates to an air separation device.

[Conventional technology]

As an effective method of using the blower side of an expansion turbine in a conventional air separation device, Japanese Patent Publication No. 56-34787
As described in this issue, waste gas rich in oxygen valves, which is unnecessary after nitrogen purification, is channeled to the blower side of an expansion turbine to increase its pressure, and then adiabatically expanded in the expansion turbine.

[Problem that the invention seeks to solve]

In the above conventional technology, since the flow rate on the blower side of the expansion turbine and the flow rate on the expansion turbine side are the same, a sufficient compression ratio on the blower side cannot be obtained, and the blower population of the air heat exchanger and the outlet flow rate are the same. There was a problem in that extra hot end loss occurred.

The purpose of the present invention is to increase the compression ratio on the blower side of the expansion turbine to increase the amount of cold generated by the expansion turbine, and further to reduce the blower population and the i-end loss at the outlet of the air heat exchanger. be.

[Means for solving problems]

The above object is achieved by branching part of the feed air before it enters the air heat exchanger and supplying it to the outlet side of the blower of the expansion turbine.

[For production]

The waste gas from the rectification column is brought back to normal temperature in an air heat exchanger, then pressurized by the blower of the expansion turbine, and the pressurized gas at the outlet of the blower contains a portion of the raw air before entering the air heat exchanger. is combined and cooled by an air heat exchanger before being supplied to the expansion turbine.
By increasing the compression ratio on the side, it is possible to increase the amount of cold generated by the expansion turbine, and at the same time, it is possible to reduce the amount of waste gas whose temperature is recovered by the air heat exchanger. It is possible to reduce heat loss.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG. Approximately 8
The raw air, which has been compressed to 9 ZcrlG and from which moisture and carbon dioxide have been removed, is led to the air heat exchanger 1 through the conduit 10, where it exchanges heat with the low-temperature return gas to a temperature of about -170°C.
The liquid is cooled to a temperature of 100.degree. C., partially liquefied, and sent to the lower part of the rectification column 2 through a conduit 11. Within the rectification column 2, rectification separation is performed in each stage of rectifiers, and nitrogen, which is a product gas, is passed from the top of the column to a conduit 12.
The air heat exchanger 1 recovers the temperature to room temperature and sends it to the consumer. In addition, liquid air rich in oxygen is taken out from the bottom of the tower, guided through a conduit 13 to a nitrogen condenser 3, where it is reduced in pressure to about 5 K9/cdl G, and is liquefied by heat exchange with nitrogen gas. It vaporizes and becomes waste gas.

The waste gas vaporized in the nitrogen condenser 3 is led to the air heat exchanger 1 through a conduit 14, and after the temperature has recovered to room temperature, it is led to the blower 43 of the expansion turbine 4 through a conduit 15, and the waste gas is transferred to the air heat exchanger 1 through a conduit 14, and is then led to the blower 43 of the expansion turbine 4 through a conduit 15, where the waste gas is transferred to the air heat exchanger 1 through a conduit 14.
/ crIG to about 7.5 Kp / (-i G, cooled from about 80° C. to about 40° C. from conduit 16 through cooler 9, and then branched from conduit 10.
It joins with a part of the raw material air supplied from the conduit 17 through the valve 5, flows through the air heat exchanger 1 again, is cooled to about -135°C, and is then introduced into the turbine 4b side of the expansion turbine 4. The air pressure is then reduced to approximately 0.3 Kg/crlG by adiabatic expansion in the expansion turbine 4, generating the necessary cooling for the device, and then guided through the conduit 19 to the air heat exchanger 1, where the temperature is restored to normal temperature and then released into the atmosphere. is released. In addition, a pressure regulator 8 is connected to the waste gas conduit 14 from the nitrogen condenser 3.
A bypass pipe equipped with a bypass valve 6 is provided between the waste gas pipe 14 and the waste gas pipe 19 from the expansion turbine 4 to keep the inlet pressure of the blower 43 constant at all times. By operating the valve 5 while monitoring the amount of raw air supplied to the rectification column 2 with a flow meter 7 installed in the raw air conduit 11, air is supplied to the outlet side of the blower 4a of the expansion turbine 4. Adjust the amount of raw air.

According to this embodiment, since a part of the raw material air is supplied to the blower outlet side of the expansion turbine, (1) the compression ratio on the gastric side can be increased. That is,
According to the adiabatic compression equation, if the amount of cold generated by the expansion turbine is constant, the air volume of the blower is 0! - is inversely proportional to the 0.3 power of the compression ratio, so if the air volume of the expansion turbine and the blower are the same, and the air volume ratio of the blower side is ' / 1.8, the compression ratio will be 1.3 It can be increased from 1.55 to 1.55.

(2) It is possible to reduce the heat loss of the air heat exchanger. Since it is supplied to the blower side of the expansion turbine, it is possible to reduce the amount of waste gas that is recovered from a cryogenic temperature to room temperature by a degree.For example, in the above case, the temperature loss of the air heat exchanger can be reduced by about 1
It can be reduced by 5%.

(3) Equipment such as a rectification column and air heat exchanger, and piping can be downsized. That is, it is sufficient to supply the minimum amount of raw material air necessary for rectification to the deep cold side, and the equipment and piping can be made smaller accordingly.

(4) Since the expansion ratio in the expansion turbine increases, the amount of feed air can be reduced.

[Effects of the Invention] According to the present invention, the compression ratio on the blower side of the expansion turbine can be increased to increase the amount of cold generation in the expansion turbine, and the blower population of the air heat exchanger can be increased. It is possible to reduce the loss of moisture at the outlet.

[Brief explanation of the drawing]

The first factor is a system diagram of an air separation device showing an embodiment of the present invention. 1... Air heat exchanger, 2... Rectification column,
3...Nitrogen condenser, 4...Expansion turbine, 4a...Blower-14b...Turbine, 5...Valve, 6... ...Bypass valve,
7...Flowmeter, 8...Pressure regulator, 9
......Cooler, 10-19...Conduit,
Bypass pipeline agent Patent attorney Masaru Ogawa
One soup

Claims (1)

[Claims] 1. The raw air from which moisture and carbon dioxide have been removed is passed through an air heat exchanger, cooled by low-temperature return gas, and then introduced into a rectification tower where it is rectified and separated into product gas and waste gas. In the air separation device, the air heat exchanger includes the air heat exchanger, in which the gas is returned to room temperature through the air heat exchanger and then pressurized by a blower of the expansion turbine, and the pressurized gas is cooled through the air heat exchanger and then supplied to the expansion turbine. 1. An air separation device comprising: a conduit for making a part of the raw material air before entering the vessel join the pressurized gas at the outlet of the blower of the expansion turbine.