JPH02280811A - gas 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 Field of Industrial Application The present invention relates to a gas separation device, and in particular to a PSA type (Pres
The present invention relates to a gas separation device suitable for use as a nitrogen generating device or an oxygen generating device, for example.

Conventional technology In general, a PSA gas separation device uses an adsorbent made of molecular sieve carbon to separate air into nitrogen and oxygen.
Either one is taken out and used as a product gas.

For this reason, for example, in a PSA type nitrogen generator,
@Suction filled with adhesive! ! An adsorption step in which compressed air is introduced into the tank to raise the pressure, and a desorption step in which the inside of the adsorption tank is opened to the atmosphere or depressurized using a vacuum pump are repeated. , extract nitrogen to the outside,
On the other hand, in the 11!2 adsorption step, the attached oxygen is desorbed and prepared for the next adsorption step. Since nitrogen, which is a product gas, is taken out after the inside of the adsorption tank is in an ascending state, the nitrogen gas generated is similar to WIR and has a large pressure change. For this reason, when nitrogen gas is used continuously at a constant pressure, a product tank is provided on the extraction side and the nitrogen gas is stored in the product tank.

In conventional equipment, when the equipment is stopped, it is stopped immediately, or the remaining gas in the adsorption tank is quickly discharged into the atmosphere during the desorption process, and the pressure inside the adsorption tank is reduced to atmospheric pressure. The process had stopped.

Problems to be Solved by the Invention However, in the conventional equipment, when restarting, the operation starts from the state in which the adsorption tank is in the exhaust process, that is, the product gas (nitrogen gas) is ) Since there remains a large amount of gas (e.g. oxygen) that reduces the purity of nitrogen gas, the adsorption process described above must be repeated, and it takes a considerable amount of time to generate nitrogen gas of the specified purity. There are issues such as:

Therefore, an object of the present invention is to provide a gas separation device that solves the above problems.

Means for Solving the Problems The present invention provides the above-mentioned gas separation apparatus, which stops the discharge of product gas when an operation stop signal is input, and then discharges the gas in the adsorption tank when the removal of the adsorption tank in a pressurized state is completed. The apparatus is equipped with means for returning high-purity gas in the product tank to the adsorption tank and scavenging the inside of the adsorption tank with the high-purity gas.

Product gas is transported into the II tank and restarted 113
Since operation can be started with high-purity product gas stored in the tank 118, high-purity product gas can be generated in a short period of time from the start of restart.

Embodiment FIG. 1 shows an embodiment of the gas separation apparatus according to the present invention.

am, 1.2 is the first and second adsorption tank, and each adsorption tank 1.2 is the first and second adsorption tank.
2 is filled with molecular sieve carbons IA and 2A, respectively.

3 is a compressor that serves as a compressed air supply source, and the compressed air from the compressor 3 is supplied to a dryer 4, a supply flow adjustment valve 5,
Air is supplied alternately to the yam tanks 1 and 2 via piping 6.7, and for this reason, air supply valves 8.9 each consisting of an N4a valve are installed in the middle of the piping 6.7. It is provided.

10.11 is a pipe for discharging gas from the adsorption tanks 1 and 2 during desorption, and is connected to a common discharge pipe 12, and the discharge pipe 12 is designed to discharge desalted exhaust gas. In the middle of the pipes 10 and 11, adsorption tanks 1.
Gas exhaust valves 13 and 14 are provided which are electromagnetic valves that alternately exhaust the 1!211 exhaust gas in each half cycle.

Reference numerals 15.16 and 15.16 are take-out valve pipes for taking out the nitrogen from adsorption e11.2 respectively, 17 is take-out pipes connected to each pipe 15.16, and in the middle of pipe 15.16 there is a half-cycle darkness (1lJtl) described later. At the bottom, take-out valves 18 and 19 each consisting of a solenoid valve that opens alternately are provided. Further, the extraction pipe 17 is connected to the product tank and the nitrogen tank 20 at 6.
is connected to.

In addition, in the middle of the take-out drain pipe 17, there is a take-out rj consisting of a solenoid valve.
An ar11 valve 21ζ and a take-out flow Ill regulating valve 22 for adjusting the flow rate of nitrogen gas supplied to the nitrogen tank 20 are provided. Note that the take-out valve 111 is open to take out nitrogen gas, but as will be described later, the take-out valve 18.
19 are opened at the same time to perform a pressure equalization operation between the first and second tanks 1 and 2.

23 is a pressure switch that detects that the pressure within the nitrogen tank 20 has reached a predetermined pressure. '24 is nitrogen tank 20
A take-out valve 25 made of a solenoid valve is provided in the middle of the take-out pipe connected to the take-out pipe, and a take-out flow ff1W regulating valve 26 is provided.

27 is an oxygen sensor, which is taken out and distributed via an on-off valve 28 consisting of a solenoid valve. 24 and detects the oxygen purity of the gas taken out from the nitrogen tank 20. or,
The oxygen purity detection signal from oxygen sensor + J27 will be described later!
The signal is input to the 11111 circuit 29.

The oxygen sensor 27 is a magnetic type sensor that utilizes the paramagnetism of oxygen molecules; when oxygen enters the electrolyte through the 711'IA membrane, a redox reaction occurs at the electrodes. An electromagnetic MK sensor that utilizes the flow of current, electrodes are provided on the inner and outer surfaces of zirconia porcelain, and S! A zirconia graphene sensor or the like is used, which utilizes the electromotive force generated depending on the purity of the wire.

30 is the purity of nitrogen extracted from the extraction pipe 24, that is, the acid*
, with the purity setting switch to set the a degree, the nitrogen tank 20
It is set appropriately depending on the purity of the nitrogen gas to be extracted from the nitrogen gas.

In addition, the υfi11 circuit 29 is, for example, a micro combination l-
It has one stage of valve control, consisting of a valve control, an oxygen sensor 27, a purity setting switch 30, etc. on the input side. Pressure switch 23
6 are connected, and the output side is connected to the aforementioned supply flow rate regulating valve 5. The memory circuit of this I control circuit 29 includes a program A that opens and closes eight valves in a normal operation mode that generates nitrogen gas, and a program B that opens and closes eight valves when stopping operation.

The valve opening degree of the supply flow rate regulating valve 5 is set to 61° so that the nitrogen purity taken out is maintained at the value set by the purity setting switch 3o.
1111 program C is stored.

Furthermore, 31 is a sequencer, based on the program of $13111 circuit 29, air supply valves 8, 9, gas discharge valves 13, 14, extraction valves 18, 19, extraction opening/closing valve 2.
1. Open the take-out valve 25 and the on-off valve 28.

It should be noted that the sequencer 31 allows Itn rfl &11
Each of the electromagnetic valves is opened when energized by the supply of a quantity valve signal, and closed by a spring force when not energized.

Next, the operation of the nitrogen generating station configured as described above will be explained. Note that the control circuit 29 executes the processing shown in FIG.

First, the basic operation of the nitrogen generator will be described with reference to FIGS. 3 and 4.

First, when the start switch is turned on in step S1 in FIG. 2, the four-way control 29 moves to step S2 and executes program A for normal operation.

That is, when the nitrogen generator is started, the lIIm circuit 29 (
(not shown), the sequencer 31 operates to generate nitrogen through normal operation.

First, as shown in FIG. 4, the dynamics of ■, ■, ■ are executed. ■ in Figure 3 indicates air supply valve 9 and gas discharge valve 1.
3 is opened, compressed air as a raw material gas is supplied to the second adsorption tank 2, and the second adsorption tank 2 is in the ascending state, S prefecture is adsorbed to the molecular sieve carbon 2A, while the first @ The tank 1 is under reduced pressure, and the adsorbed oxygen is being desorbed and discharged.

Next, ■ in Fig. 3 indicates the air supply valve 9 and the gas discharge valve 1.
3, the take-out valve 19 and the take-out on/off valve 21 are newly opened to take out nitrogen gas from the second adsorption tank 2. At this time, the first adsorption W41 remains in a reduced pressure state.

Next, ■ in Fig. 3 is a pressure equalization operation, and each take-out valve 18.1
At the same time, the take-out on-off valve 21, the air supply valve 9, and the gas discharge valve 13 are closed. This allows the second
The nitrogen-enriched gas remaining in the adsorption tank 2 is transferred to the first adsorption tank 1.
The adsorption tanks 1 and 2 have equal pressure. Note that the pressure equalization operation usually takes 1 to 10 seconds.

This means that the Tatene half cycle of one cycle has been completed, and the air supply valve 8 and the gas discharge valve 14 have been completed.
By opening the valve, as shown in FIG. 4(B), the latter half cycle shown by ■ to ■ in FIG. 3 is repeated. Thus, if one cycle is 120 seconds, nitrogen gas can be taken out from the adsorption tanks 1 and 2 in the latter half of each half cycle and supplied to the nitrogen tank 20. After a while after startup, the purity of the nitrogen gas generated becomes stable.

Here, when a stop switch (not shown) is turned on in step S3 in FIG. 2, the control circuit 29 executes the process of program B. That is, by turning on the stop switch, the take-out valve 25 is first closed (step 3).
4). In the next step S5, the above-mentioned normal operation (the same nitrogen gas generation operation as in step S2) is performed. At this time, the take-out valve 25 of the nitrogen tank 20 is closed, so nitrogen is generated at 1ffi1.2 of suction, and when one cycle shown in FIGS. 3 and 4 is repeated several times, the nitrogen tank 20 is closed.
Inside 0, high purity nitrogen gas is further stored and the pressure increases.

In the next step S6, when the stop signal is input, the promotion state is 11.
When the removal of fi is completed (inside the sequencer 31, it is detected by time management means such as timer up of a predetermined timer), it is detected that the pressure in the nitrogen tank 20 has increased to a predetermined pressure or more, and the step is started. Normal operation of S5 is stopped. Subsequently, all electromagnetic valves are closed (step 87).

Next, the gas exhaust valves 13 and 14 are opened at 1... (step S8), and this state is maintained for the time M t I.
Step 89). During this time, the residual gas in the adsorption tank 1.2 is exhausted to the atmosphere, and the pressure inside the snack tanks 1 and 2 is reduced to atmospheric pressure.

In the next step 810, the take-out valves 18 and 19 are simultaneously opened. As a result, the high-purity nitrogen gas accumulated in the nitrogen tank 20 is transferred to the suction tank 1 through the take-out valves 18 and 19.
, 2. Therefore, the low-purity nitrogen gas and oxygen remaining in the adsorption tanks 1 and 2 are degassed by the pressure of nitrogen gas from the nitrogen tank 20 through the gas discharge valve 13.14, and the inside of the adsorption tank 1.2 is High purity nitrogen gas saves air. In step 811, when the reflux of nitrogen gas into the above-mentioned @nursing tanks 1 and 2 is continued for a period of time 1j fl j 2, the remaining gas is exhausted from the adsorption tank 111.2, and the interior of the adsorption tank 111.2 is filled with high-purity nitrogen gas. Next, the gas discharge valve 13.14 and the gas extraction valve 18.1 opened in the above-mentioned gas loss and reflux process.
9 is closed (step 512).

And the sequencer 31 and t, 1) il11 circuit 29
puts the entire device into stop mode (step 513).

In this way, when the stop switch is operated, the processes in steps 83 to 313 described above are executed, so when the apparatus is stopped, the high-purity gas stored in the nitrogen tank 20 is stored in the adsorption tank 1.2. Filled with nitrogen gas. Therefore, when the startup switch is turned on to restart, high purity can be obtained in a much shorter time than when the adsorption tank 1.2 is left open to the atmosphere or stopped as it is in the conventional equipment. It becomes possible to take out nitrogen gas from the adsorption tanks 1 and 2.

Therefore, even if the equipment is stopped at the end of the previous day's work, for example, the preparatory operation time (time required) after turning on the start switch the next morning is shortened, and nitrogen gas of a predetermined purity can be obtained after the worker starts it up. You no longer have to wait for a long v1 question until you are asked,
Work efficiency is improved.

In the above embodiment, the gas discharge valve 13.14 and the take-out valve 18.19 were opened at the same time in step 812, but after a while after the gas discharge valve 13.14 was opened. The take-out valves 18 and 19 may be opened.

Furthermore, the take-out process, the evacuation of adsorption tanks 1 and 2, and the continuous flow r process, which are executed when the stop switch is turned on, are processes that are performed during the stop operation, and are performed during normal operation, that is, the pressure increase shown in FIG. , extraction, pressure equalization, and pressure reduction [set to be executed separately from the culm].

In addition to the above embodiments, it is also possible to perform pressure equalization for one culm by inputting a stop signal and then return the product gas in the product tank to the adsorption tank, but in this case, the pressure in the adsorption tank after the pressure equalization step The residual gas in the adsorption tank must be exhausted after the pressure is lower than when it is taken out, and the residual gas in the adsorption tank cannot be sufficiently degassed. That is, when the product gas is refluxed after homogenization [E][t4111!] with residual gas remaining in the adsorption tank! As a result, the KI group of the gas in the adsorption tank after reflux decreases.

Effects of the Invention As described above, the gas separation device according to the present invention has a vti? Immediately before the machine stops, the residual gas in the adsorption tank is exhausted, and then the high-purity product gas in the product tank is circulated back into the adsorption tank to scavenge the adsorption tank and shut down. Operation can now be started with the tank filled with high-purity product gas, making it possible to extract product gas of specified purity in an extremely shorter time than with conventional equipment, which stops when the tank is exhausted. It has the feature of snow that can shorten the time it takes to start up.

[Brief explanation of drawings]

Fig. 1 is a schematic configuration diagram of an embodiment of the gas separation device according to the present invention, Fig. 2 is a flowchart of the processing executed by the 1Ill 6!1 circuit, and Figs. 3 and 4 are the gas separation device. FIG. 1... first adsorption tank, 2... second @ snack tank, 3...
・Compressor, 5... Supply flow adjustment valve, 8.9...
・Air supply valve, 13.14... Gas discharge valve, 18
゜19...Takeout valve, 20...Nitrogen tank, 21.
...Take-out on-off valve, 27...Oxygen sensor, 29...
Control circuit, 30...Purity setting switch, 31...Sequencer. Patent applicant: Tokiko Co., Ltd. Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] A compressed raw material gas is supplied to an adsorption tank filled with an adsorbent, and while the adsorption tank is in a pressurized state, a take-out valve is opened to produce the gas produced by the adsorbent. In a gas separation device that stores product gas in a product tank, when an operation stop signal is input, the discharge of the product gas is stopped, and after the removal of the adsorption tank in a pressurized state is completed, the gas in the adsorption tank is discharged. A gas separation device comprising means for returning high-purity gas in the product tank to the adsorption tank and scavenging the inside of the adsorption tank with the high-purity gas.