JPH01194923A - Method for controlling pretreatment equipment for air separator - 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 a pre-treatment device heat exchanger for an air separation device, and in particular, to a land treatment device for an air separation device suitable for a two-span switching type PSA type absorption tower facility. This relates to a control method.

[Conventional technology]

Adsorption tower equipment, which is generally used as a pretreatment device for air separation equipment, is supplied with gas for regeneration by waste gas supplied from the air separation equipment. For this reason,
Since regeneration gas is not supplied to the adsorption tower equipment when the air separation equipment is started up, a portion of the recycled air is supplied to the adsorption tower equipment as regeneration gas using a bypass pipe and a bypass valve branched from the purified air outlet piping of the adsorption tower. supplying. This bypass valve was operated manually or by adjusting the main pipe pressure of fresh gas.

Note that related devices of this type include, for example, Japanese Patent Application Laid-open No. 55-95079.

[Problem to be solved by the invention]

The above-mentioned conventional technology does not take into account pressure fluctuations that occur due to sudden changes in the flow rate of the regenerating gas supplied from the air separation device, and the regenerating gas stops flowing at the completion of the adsorption tower regeneration process, resulting in rapid When the pressure increases and the regeneration gas begins to flow at the start of the regeneration process, a phenomenon occurs in which the pressure rapidly decreases, causing a problem in that the pressure fluctuations cause a disturbance in the control system.

An object of the present invention is to provide a method for controlling a pretreatment device for an air separation device, which stabilizes the supply of regeneration gas to the adsorption tower and minimizes the bypass flow rate of purified air.

[Means to solve the problem]

The above purpose is to switch the adsorption tower from the switching control device.
The timing of the h main process of the S absorption tower is taken out as a signal, and the output d is obtained when the output signal of the regeneration gas pressure control valve becomes stable.
This is achieved by comparing the magnitude of the value with a preset value and adding or subtracting the comparison result to the output signal of the valve opening setting device of the bypass circuit.

[For production]

The pressure fluctuations that occur at the start and completion of the regeneration process of the adsorption tower can be reduced by creating a dead period for the control amount (valve opening of the regeneration gas pressure control valve) using a timing signal from the adsorption tower switching control device. The bypass flow rate of purified air can be minimized while the regeneration gas flow rate is stabilized.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG.

In the figure, it passes through the suction filter l and the pressure ma2 is about 51
The raw air compressed to ζpf/cd is transferred to adsorption towers 3, (3
'), where moisture and OO2 that solidify in the downstream air separation device are adsorbed and removed, and the purified air is sent to the air separation device. On the other hand, the regeneration gas comes from the public party separation equipment.
Adsorption tower 3. (3').

The supplied regeneration gas causes the adsorption tower 3. (3') is regenerated, and the regenerated gas is discharged to the atmosphere. Adsorption tower 3, (
The switching between the adsorption process and the regeneration process in step 3' is performed by opening and closing the switching valves 4A, 5A, 4B, and 58.6 in response to a signal from the switching control device 9. The control procedure for the second switching operation is shown in Figure 9A2.

In this embodiment, before the air separation device d is started, no regeneration gas is supplied from the air separation device, so the bypass valve 8 is opened and the amount of recirculation gas is secured by purified air. In addition, when the air separation device is in operation and the regeneration gas 9 increases, the regeneration gas artificial pipe 10 is connected to the adsorption tower 3. (3
'), the pressure loss to the atmosphere increases, so the p4 raw gas input pressure 11 increases, the regeneration gas pressure control valve 7 is opened, and the gas is discharged to the atmosphere. Therefore, when the total amount of regeneration gas satisfies the regeneration gas requirement, the regeneration gas pressure control valve 7 is open. However, as shown in FIG. 2, the opening degree of the regenerating gas pressure regulating valve 7 is greatly changed every time the adsorption tower 3 (3') is switched. Output a timing signal for an appropriate process. The valve opening degree is controlled by increasing or decreasing the opening degree signal of the valve in the bypass circuit only during the time when this signal is received.

By performing the above operation, the bypass flow rate of purified air can be gradually reduced each time the regeneration gas supply amount gradually increases by starting the air separation device.

According to this embodiment, when the air separation device is started up, the regeneration gas of the adsorption tower used for switching can be stably supplied without being affected by pressure fluctuations caused by switching the adsorption tower. , and the purified air bypass rlLfl can be minimized.

〔Effect of the invention〕

According to the present invention, when purified air is used for regeneration gas, it is possible to stabilize the supply of regeneration gas at the start of the regeneration process or at the completion of the regeneration process, and to reduce the bypass flow rate of purified air. .

[Brief explanation of the drawing]

FIG. 1 is a system diagram of a pretreatment device for an air separation device according to an embodiment of the present invention, and FIG. 2 is a time chart showing a control procedure for an adsorption tower. ■・・・Suction filter, 2・・・Compression &,
3.3'...Adsorption tower, 4A, 4B...Switching valve (for air), 5A. 5B...Switching valve (for regeneration gas), 6...
・Switching valve (for pressurization), 7... Regeneration gas pressure control valve, 8... Bypass valve, 9... Switching control device representative Patent attorney Katsuo Ogawa. ′) (j M/Fig.

Claims (1)

[Scope of Claims] A method for controlling a pretreatment device for an air separation device, which uses a PSA adsorption tower with one and two towers switching type, and regenerates the adsorption tower with regeneration gas supplied from the air separation device, The opening degree of the valve that discharges to the atmosphere is adjusted by the pressure of the regeneration gas supplied from the air separation device, and the output signal of the opening degree of the valve is used to open the valve of the bypass circuit that uses the purified gas for regeneration. 1. A method for controlling a pretreatment device for an air separation device, the method comprising: controlling the flow rate of a pretreatment device for an air separation device to stabilize the supply of regeneration gas to an adsorption tower and minimize the bypass flow rate of purified air. 2. In claim 1, the control is such that the valve of the bypass circuit is closed when the output signal of the valve opening degree released to the atmosphere is larger than a set value every time the adsorption tower is switched. A method for controlling a pretreatment device for an air separation device, characterized in that, on the contrary, when the output signal of the valve opening degree is smaller than a set value, the valve of the bypass circuit is controlled to be opened.