JPH03213113A - Method and apparatus for vacuum regeneration of absorbent - Google Patents

Abstract

PURPOSE:To prepare objective gas in low cost by a simple apparatus by utilizing the gas stream generated when the high pressure gas in one adsorbing tank is discharged to the atmosphere to reduce the pressure in the other adsorbing tank to a pressure lower than atmospheric pressure. CONSTITUTION:The high pressure gas in an adsorbing tank 10c is discharged to the atmosphere through the first exhaust pipe 6c and the primary side 8c of an air ejector 8. Whereupon, negative pressure is generated on the primary side 8b of the air ejector 8 by the gas stream ejected on the primary side 8a of the air ejector 8 and the gas on the secondary side 8b is sucked in the gas on the primary side 8a to be discharged to the atmosphere along with the gas on the primary side. As a result, the pressure in an adsorbing tank 10b in an atmospheric pressure state is reduced to a pressure lower than atmospheric pressure through the second exhaust pipe 7 and the second exhaust valve 4b. By this constitution, the manufacturing cost of objective gas is reduced without requiring power for reducing pressure.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method and apparatus for separating a target gas from a mixed gas consisting of two or more components by a pressure fluctuation adsorption method (hereinafter referred to as PBA method). , relates to a method and apparatus for regenerating an adsorbent used for separation under reduced pressure.

[Conventional technology]

In general, the PBA method is a method in which a raw material gas consisting of two or more components is fed at high pressure into an adsorption tank filled with an adsorbent, and the non-target gas is adsorbed by the adsorbent to separate the target gas. adsorption process.

This is a method in which a stable target gas is separated by alternately repeating a low-pressure regeneration process in which an adsorbent whose adsorption effect has decreased is regenerated under low pressure.

The target gas separation system using this PaA method is generally equipped with two or more adsorption tanks, and each process including at least the high pressure adsorption process, the pressure equalization process, the atmospheric pressure regeneration process, and the pressure regeneration process is alternately performed. Highly concentrated and stable target gases are collected repeatedly. Below, each raccoon dog will be explained.

The high-pressure adsorption step is a step in which high-pressure raw material gas is fed into an adsorption tank filled with an adsorbent, non-target gas components are adsorbed by the adsorbent, and target gas is separated.

The pressure equalization step is a step in which the first adsorption tank, which has completed the high-pressure adsorption step and is filled with the high-pressure target gas, and the second adsorption tank, which has completed the reduced-pressure regeneration step, are connected to the second adsorption tank. This is a step of efficiently increasing the pressure inside the second adsorption tank by feeding the target gas at a high temperature from the second adsorption tank into the second adsorption tank.

The above-mentioned atmospheric pressure regeneration step is to release the gas in the adsorption tank that has completed the high-pressure adsorption step and pressure equalization step into the atmosphere to quickly reduce its pressure.1. This is a step of releasing the adsorbent from the adsorbent and regenerating the adsorbent.

The reduced pressure regeneration step is a step in which the adsorbent is further regenerated by reducing the pressure in the adsorption tank using a vacuum pump or the like after the atmospheric pressure regeneration step.

Recently, with the increase in gas demand, small and medium-sized PSA equipment that can easily produce the target gas at low cost is attracting attention. Since the utilities used greatly increase the production cost, the adsorbent regeneration process is often carried out only at an atmospheric pressure regeneration process without using a vacuum pump. On the other hand, considering the regeneration efficiency of the adsorbent, it is more advantageous to carry out a reduced pressure regeneration step, and regarding this reduced pressure regeneration method, JP-A-63-182016 and JP-A-64-2181
It is disclosed in Publication No. 8.

The method disclosed in Japanese Patent Application Laid-open No. 83-182018 is as follows:
This method utilizes the negative pressure of the air compressor during no-load operation to reduce the pressure inside the adsorption tank, and is disclosed in Japanese Patent Application Laid-Open No. 64-2711.
The method disclosed in Publication No. 1,1 involves supplying air compressed by an air compressor to the primary side of an ejector, thereby reducing the pressure in the adsorption tank through an exhaust pipe connected to the secondary side of the ejector. The first T that lowers the
[Problems to be Solved by the Invention] However, the methods disclosed in JP-A-65-182016 and JP-A-64-27813 are applicable only when there is only one adsorption tank. However, there was no easy method or device for reducing pressure in a psm device with two or more adsorption tanks with good production efficiency.

The present invention was made in view of the above circumstances, and aims to provide a method and device for easily reducing the pressure of an adsorption tank in a PS system equipped with two or more adsorption tanks. .

[Means to solve the problem]

The first invention of the present invention to solve the problem described above is an invention of a method, which includes at least two steps of a high pressure adsorption step and a reduced pressure regeneration step for at least two or more adsorption tanks filled with adsorbent. In a method for separating a target gas by repeating the steps alternately.

When regenerating the adsorbent with reduced adsorption efficiency under reduced pressure,
First, by opening the exhaust valve of the first adsorption tank that is in a high pressure state, the high pressure gas in the first adsorption tank is released to the atmosphere to bring the inside of the adsorption tank to atmospheric pressure, and then.

Open the exhaust valve in the second adsorption tank, which is also under high pressure,
The exhaust pipe 1 communicating with the exhaust valve of the first adsorption tank is characterized in that the pressure inside the first adsorption tank is reduced to a pressure lower than atmospheric pressure by releasing the high pressure gas in the second adsorption tank. It is something.

Further, a second invention is an invention of an apparatus, in which a target gas separation apparatus comprising at least two or more adsorption tanks filled with an adsorbent includes a first exhaust valve provided in each of the adsorption tanks, and a first exhaust valve provided in each of the adsorption tanks; The first exhaust pipe includes a second exhaust valve provided in the adsorption tank, a first exhaust pipe communicating with each of the first exhaust valves, and a second exhaust pipe communicating with each of the second exhaust valves. The first exhaust pipe and the second exhaust pipe are connected to each other so that the exhaust direction of the second exhaust pipe is a forward direction at an appropriate angle with respect to the exhaust direction of the exhaust pipe.

[Effect]

In order to carry out the method of the present invention using the apparatus of the present invention as described above,
First, after the first adsorption tank finishes the high-pressure adsorption process, the first exhaust valve of the first adsorption tank is opened to release the high pressure gas in the first adsorption tank to the atmosphere, and the inside of the first adsorption tank is Bring to a state close to atmospheric pressure. Thereafter, the first exhaust valve of the first adsorption tank is closed and the second exhaust valve is opened, and the first exhaust valve of the second adsorption tank is opened to release the high pressure gas in the second adsorption tank to the atmosphere. At this time, the gas flow from the second adsorption tank flowing through the first exhaust pipe creates a negative pressure in the second exhaust pipe communicating with the first exhaust pipe, and the gas flow from the first exhaust pipe flows into the second exhaust pipe. The gas in the second exhaust pipe is released into the atmosphere together with the gas in the first exhaust pipe. As a result, the pressure within the second adsorption tank communicating with the second exhaust pipe via the second exhaust valve is reduced to a pressure lower than atmospheric pressure.

〔Example〕

Hereinafter, examples of the method of the present invention and specific embodiments of the apparatus of the present invention for carrying out the method will be described based on the attached drawing ml. FIG. 1 is an explanatory diagram showing an embodiment of the apparatus of the present invention. In the figure, (A) is the adsorption tank section, (B) is the product supply section, (0 is the air supply piping section, (to) is the exhaust piping section, (8)
is the extraction piping section, and the device of the present invention has these sections (A
) (B) (0) (9) (Consists of Q and an air compressor (2) installed near these parts. Each part will be explained in detail below.

The adsorption tank section (5) has three adsorption tanks (10
a) (10b) (10C) Caranal monotheary, M adsorption tank (10a) (lob) (10c) are doing.

The product supply section (B) has a product tank (15) and a product tank (1).
5), and a nitrogen supply valve (16) provided on the nitrogen supply pipe (17).

The air supply piping section IC) has an air supply valve (3a) and an air supply pipe (1) connected to the lower part of the adsorption tank (10a).
a), an air supply valve (3b), and the adsorption tank (
The air supply pipe (1b) connected to the lower part of the air supply valve (10b) and the air supply valve (
3C) and an air supply pipe (1C) connected to the lower part of the adsorption tank (IOC), and these air supply pipes (Ia) (1
b) an air supply pipe (1) connected to (1c), and the other end of the air supply pipe (1) is connected to the air compressor (2).

The exhaust piping section (9) includes a first exhaust pipe (6a) and a second exhaust pipe (7a) branched from the air supply pipe (1a) between the adsorption tank (1oa) and the air supply valve (3a). % Air supply pipe (1b) between the adsorption tank (1ob) and the air supply valve (3b)
) branched from the first exhaust pipe (6b) and the second exhaust pipe (7
b), a first exhaust pipe (6C) and a second exhaust pipe (7C) branched from the air supply pipe (IC) between the adsorption tank (10c) and the air supply valve (3C), and the second exhaust pipe (7a) (7
b) (7C) The second exhaust pipe (a) connected to each of the first exhaust pipes (6a) (6b) (8c) 'c, the first exhaust pipe (6) connected to each of the air ejectors ( 8),
It consists of a silencer (9). The second exhaust pipe (7a) has a second exhaust valve (4a), and the second exhaust pipe (7a) has a second exhaust valve (4a).
7b) has a second exhaust valve (4b) and a second exhaust pipe (7C
) has a second exhaust valve (4C), the first exhaust pipe (6a) has a first exhaust valve (5a), and the first exhaust pipe (6b) has a first exhaust valve (5b). , the first exhaust pipe (6C) has a first exhaust valve (5C). Further, the other end of the first exhaust pipe (6) is connected to the primary side (8a) of the air ejector (8).
The other end of the second exhaust pipe (1) is connected to the secondary side (8b) of the air ejector (8), and the silencer (8C) is connected to the discharge side (8C) of the air ejector (8). 8) is connected.

The above-mentioned take-out piping section (1) includes a take-out pipe (14a) having a take-out valve (13a), a take-out pipe (14b) having a take-out valve (15b), and a take-out valve (13C).
a take-out pipe (14c) having a
Ha) (14b) (14C) It is connected to the extraction pipe (14) and the pressure equalization pipe (11a) having the pressure equalization valve (12a).
), a pressure equalizing pipe (11b) having a pressure equalizing valve (12b),
It consists of a pressure equalizing pipe (11C) having a pressure equalizing valve (12C). The other end of the take-out pipe (14a) is connected to the adsorption tank (10a), and the take-out pipe (14b) is connected to the adsorption tank (10a).
The other end is connected to the adsorption tank (10b), and the extraction pipe (
The other end of 14C) is connected to the adsorption tank (IOC). Further, one end of the pressure equalizing pipe (12a) is connected to the take-out valve (
13a) and the adsorption tank (10a)
a) and the other end is connected to the take-out valve (175
b) and the take-out pipe (14b) between the adsorption tank (10b)
The configuration is connected to the Similarly, the pressure equalizing pipe (12
b) has one end connected to the take-out valve (13b) and the adsorption tank (
10b) and the other end is connected to the takeout pipe (14b) between the takeout valve 1'13C) and the adsorption tank (10b).
The pressure equalizing pipe (12C) has one end connected to the take-out pipe (14c) between the take-out valve (13a) and the adsorption tank (tea). A take-out pipe (Ha) is connected to the take-out pipe (Ha), and the other end is connected to the take-out pipe (Ha) between the take-out valve (Hc) and the adsorption tank (IOC).
14C). Further, the other end of the take-out pipe (14) is connected to the upper part of the product tank.

Next, a manner in which nitrogen is separated by continuously operating the apparatus of this embodiment having the configuration described below will be explained based on FIG. 2. As shown in the figure, each adsorption tank (10a) (10b) (
10c) +c Each process of high pressure adsorption process, pressure equalization process, atmospheric pressure regeneration process, and reduced pressure regeneration process is repeated continuously, but the phase of the cycle is different from each adsorption tank (10a) (10b) (IO
C), as shown in the figure.

The aspects of each part of the apparatus during the 1 hour T1 to T1 will be described below.

T1. At this time, the adsorption tank (10a) performs the pressure equalization process,
The adsorption tank (10b) performs the atmospheric pressure regeneration process, and the adsorption tank (10c)
) has just finished the pressure equalization process, and the pressure equalization valve (12C)% nitrogen supply valve (16) and first exhaust valve (5b) shown in Figure 1 are open, and all other valves are closed. It is in. After that, the pressure equalization valve (12C) and the first exhaust valve (, 5b)
Close the air supply valve ($a), take out valve (13a),
By opening the second exhaust valve (4b) and the first exhaust valve (5C), the adsorption tank (0va) is placed in the high-pressure adsorption process.
ob) is transferred to a reduced pressure regeneration process, and the adsorption tank (10C) is transferred to an atmospheric pressure regeneration process. That is, an adsorption tank (lea
), air, which is a raw material gas pressurized by an air compressor (2), is fed into the adsorption tank (10a) through the air supply pipe (1) and the air supply valve (5a). The oxygen component in the air is adsorbed by the M2C in the air, and the remaining main component, nitrogen gas, is extracted.
) and is stored in the product tank (15) via the take-out pipe (14). At this time, the pressure inside the adsorption tank is usually 3 to 1
0 kg/cm! Q range, preferably 4-8k
g/cmtQ range.

On the other hand, in the adsorption tank (IOC), the high pressure gas in the adsorption tank is pumped through the first exhaust pipe (6c) (8) and the air ejector (8).
) is discharged into the atmosphere through the negative side (8a). At this time, the gas flow ejected to the negative side (8a) of the air ejector (8) causes the secondary side (8a) of the ejector (8) to
8b), the gas flow on the negative side (8a) draws in the gas on the secondary side (8b), and the gas on the secondary side (8b) enters the atmosphere together with the gas on the negative side (8a). released. As a result, the adsorption iff (10b) at atmospheric pressure is reduced to a pressure lower than atmospheric pressure via the second exhaust pipes (7) (7b) and the second exhaust valve (4b).

T! ; At this stage, the adsorption tank (10a) is closed by closing the air supply valve (3a), take-out valve (13a), and second exhaust valve (4b) shown in Figure 1, and opening the pressure equalization valve (12a).
) (10C) is transferred to the pressure equalization step. That is, the adsorption tank (10a) filled with high-pressure nitrogen gas and the adsorption tank (10b) in which the reduced pressure regeneration process has been completed are communicated via the pressure equalization valve (12a) and the pressure equalization pipe (lla).
10b).

T3; At this stage, the pressure equalizing valve 1'12a) in FIG.
, close the first exhaust valve (5C), and open the first exhaust valve (5a>
By opening the second exhaust valve (4C), the air supply valve (3b), and the take-out valve (13b), the adsorption tank (10a) is placed in the atmospheric pressure regeneration process, the adsorption tank (10b) is placed in the high-pressure adsorption process, and the adsorption Each tank (IOC) is transferred to a reduced pressure regeneration process.

T4i At this stage, the second exhaust valve (4C) in Figure 1
, by closing the air supply valve (5b) and take-out valve (13b) and opening the pressure equalization valve (12b), the adsorption tank (10b) (1
0c) is transferred to the pressure equalization process.

T-; At this stage, the pressure equalizing valve (12b) in FIG.
By closing the first exhaust valve (5a) and opening the air supply valve (Sc), take-out valve (13C), first exhaust valve ('6b), and second exhaust valve (4a), the adsorption tank (10a) is removed. to the reduced pressure regeneration process, the adsorption tank (10b) to the atmospheric pressure regeneration process, and the adsorption tank (10C) to the high pressure adsorption process.

T6; At this stage, the air supply valve (3C) in Fig. 1,
Close the take-out valve (13C) and the second exhaust valve (4a),
By opening the pressure equalization valve (12C), the adsorption tank (10a)
(IOC) is transferred to the pressure equalization process.

Thereafter, by sequentially repeating the operations T1 to T-, highly concentrated product nitrogen gas can be continuously produced.

The pressure at which the inside of the adsorption tank can be reduced according to this embodiment varies depending on the capacity of the adsorption tank and the diameter of the ejector nozzle.
The pressure in 8a) is 2-4 kg/cm! If it is in the Q range, a pressure reduction effect can be expected. It goes without saying that the method and apparatus of the present invention can be applied to any P8 system using two or more adsorption tanks.

〔effect〕

As described in detail below, according to the method and apparatus of the present invention,
By using the gas flow generated when high-pressure gas in one adsorption tank is released into the atmosphere, the pressure in the other adsorption tank can be reduced to lower than atmospheric pressure. Since this method does not require , the production cost of the target gas can be reduced, and the device can be made simple and compact.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing one embodiment of the apparatus of the present invention, and FIG. 2 is an explanatory diagram showing its operating state. (1) s (1a) (1b) = (lc) - Air supply pipe, (2) Air compressor, (57a), (5b), (SC) Air supply valve, (4a
), (4b), (4c)-second exhaust valve, (6a),
(6b), (6C)...first exhaust valve. (8L (sa), (6b)t (6c)"・First exhaust pipe, (7), (ra), (yb)t (rc
)・tg 2 exhaust pipe. (8) Air ejector (9) Silencer, (10a), (job)t (10c) -- Adsorption tank, (11a), (11b), (llc) --
- Pressure equalization pipe, (12a), (12b), r12c)
...Pressure equalization valve. (13a), (13b), (15c) - Outlet valve, (14), (14a), (14b), (
14C)-, take-out pipe, (15)...product tank,
(16)...Nitrogen supply valve, (17)...Nitrogen supply pipe.

Claims (2)

[Claims] (1) A raw material gas consisting of a multi-component gas mixture is fed into an adsorption device, and the target component of the raw material gas is adsorbed by an adsorbent in the adsorption device, thereby extracting a product gas from the raw material gas. A method of separation and extraction, in which a process including at least two steps, a high-pressure adsorption step and a reduced-pressure regeneration step, is repeated alternately in at least two or more adsorption tanks filled with adsorbent to separate the product target gas. In the method, when regenerating the adsorbent whose adsorption efficiency has decreased under reduced pressure, the exhaust valve of the first adsorption tank in a high pressure state is first opened to release the high pressure gas in the first adsorption tank to the atmosphere. The interior of the adsorption tank is brought to atmospheric pressure, and then the exhaust valve in the second adsorption tank, which is also in a high-pressure state, is opened, and the high pressure in the second adsorption tank is discharged to the exhaust pipe communicating with the exhaust valve of the first adsorption tank. A method for regenerating an adsorbent under reduced pressure, characterized in that the pressure inside the first adsorption tank is reduced to a pressure lower than atmospheric pressure by releasing gas. (2) In a target gas separation device comprising at least two or more adsorption tanks filled with adsorbent, a first exhaust valve provided in each adsorption tank, and a second exhaust valve similarly provided in each adsorption tank. , a first exhaust pipe that communicates with each of the first exhaust valves, and a second exhaust pipe that communicates with each of the second exhaust valves, and the second exhaust pipe has an exhaust direction with respect to the exhaust direction of the first exhaust pipe. A reduced pressure regeneration device for adsorbent, characterized in that the first exhaust pipe and the second exhaust pipe are connected to each other so that the direction is a forward direction at an appropriate angle.