JPS61161116A - Separation of gas by adsorption - Google Patents

Abstract

PURPOSE:To make the constitution of the process and the mechanism for control simple in a pressure swing process by storing desorbed gas once in a gas holder and enabling feeding of feed gas and feeding of easily adsorbable component for scavenging from the gas holder with a same blower. CONSTITUTION:A gas holder T2 is connected to the exhaust side of a vacuum pump VP to be used for evacuation in the stage of desorbing operation, and easily adsorbable component is drawn from T2. T2 is connected to the suction side of a feed gas blower through a changeover valve VAO. Feed gas or the easily adsorbable gas is fed to either one of the adsorption tower C1 or C2 through one of the corresponding valves VA1, VA2. When either one of the adsorption tower C1 or C2 begins scavenging operation after an adsorption stage, VAO is changed over to the easily adsorbable gas side from the feed gas side.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an adsorption device used for mutually separating and concentrating a mixture of a plurality of gases having different adsorption properties to an adsorbent. The simplest two-column type adsorption device that can be operated continuously will now be explained.

In the conventionally known adsorption apparatus shown in Fig. In, the reference numeral 01 indicates a first adsorption tower, and 02 indicates a second adsorption tower, each of which contains an adsorbent selected from activated carbon, zeolite, and other adsorbents. The adsorption tower is packed. Easily adsorbed components and strongly adsorbed components? From the blower B1 to the raw material gas contained,
It is supplied to either one of the adsorption towers C1 and C2 through one of the valves VA1゜"ti'A2, respectively.The gases of poorly adsorbable components that are not adsorbed in the adsorption towers C1 and C2 are supplied through the valve VO1, respectively. , VO2, and is temporarily stored in the tank T1, and then taken out of the system as a product gas.

In addition, in order to desorb easily adsorbable components adsorbed by the adsorbents of the adsorption towers C1 and C2, a vacuum pump VPK is connected to one end of each adsorption tower C1 and C2 through valves VD1 and VD2t, respectively.
By the action of this vacuum pump vP, a portion of the desorption gas is taken out of the system as a product through the pulp VDOt-, and the remainder is used for the cleaning operation described later.

Adsorption is performed using either adsorption tower CI or C2, and the other is used for desorption. Now, assuming that the first adsorption tower C1 is in adsorption operation and the second absorption tower C2 is in desorption operation, the operation method will be explained below. First, in the C1 tower, VAl
and VOl are opened, and the others are closed. In this state, the raw material gas is supplied from the bottom of the first adsorption tower C1 from the blower B1 through the pulp VA1i, and easily adsorbable components are adsorbed by the adsorbent in the first adsorption tower C1. The unadsorbed gas flows out from the top of the tower, passes through the pulp VO1t-, enters the tank T1, and is then taken out of the system as adsorbed component gas in the can.

First, in order to desorb all of the easily blue-absorbing components adsorbed by the adsorbent in the second adsorption tower C2, first, VD2 and VDOt-
Open some and close others. Due to the action of vacuum pump vP,
The pressure inside the second adsorption tower C2 is reduced through the pulp VD2'ft, and the desorption gas is passed through the pulp VDO' and taken out of the system as an easily adsorbed component gas. If this state continues for a while, the pressure in the C2 column continues to be reduced, but easily adsorbed components begin to break through from the top of the C1 column.

When this state is reached, the first adsorption tower C1 is then cleaned. In the cleaning operation, after the adsorption operation is completed and before the desorption operation, the easily adsorbed component gas discharged outside the tower by the desorption operation of another adsorption tower is temporarily removed at almost the same pressure as the adsorption pressure. Refers to an operation in which gas is introduced from one end of the column and all of the difficult-to-adsorb components remaining in the column are expelled from the other end. In the cleaning operation of the first adsorption tower C1, V
This is done by closing AI and VDOt and at the same time fully opening VN1. With this operation, the feed of the raw material gas to the C1 tower is stopped, and the gas sucked by the vacuum pump vP is sent through the entire pulp VN1 to the bottom of the first absorption tower C1, making full use of its back pressure. , the gas from the top of the C1 column is the pulp V
It will be discharged into the tank T1 via O1i, and the above-mentioned cleaning operation will be performed. After the cleaning operation is completed, the pulps VO1 and VN1 are closed and the pulps VD1 and VDOt are opened to transfer to the C1 column for desorption operation, and simultaneously with this operation in the C2 column, VA2. VO2 is opened, VD2 is closed, feed gas 1dVA2 is fed into the C2 column, and the C2 column enters the adsorption state. Thereafter, such adsorption operation, cleaning operation, and desorption operation are performed in this order for each adsorption tower, thereby making it possible to perform continuous adsorption treatment. In order to carry out all of these driving methods, 2.
In the case of a basic adsorption device, it is necessary to have one blower, one vacuum pump, and nine pulp and metal units. Furthermore, in the configuration shown in FIG. 2, atmospheric pressure acts as back pressure on the vacuum pump vP, which has the disadvantage that its efficiency is reduced.

FIG. 3 shows another conventional adsorption apparatus. In this adsorption device,
A tank T2 that receives the exhaust gas from the vacuum pump, and a blower B that sends the gas in this tank T2 to each adsorption tower only during cleaning operations.
It differs from the one shown in FIG. 2 only in that 2 is provided.

In this case, there is no reduction in the efficiency of the vacuum pump vP, the pulp VDO is omitted, the total number of required pulps can be reduced to 't-8, and the flow tt of the cleaning gas can be kept constant. [6] However, a separate blower B2 for cleaning operation is required. The conventional adsorption apparatus having such a large number of pulps and blowers has a disadvantage in that its configuration and control mechanism are complicated.

It is an object of the present invention to provide an entire adsorption device that eliminates the above-mentioned conventional drawbacks and can perform the same operation with a smaller number of pulps.

An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, parts that are the same or equivalent to those shown in FIG. 2 or 3 are designated by the same reference numerals, and their explanations will be omitted.

In the adsorption apparatus shown in Fig. 1, a tank T2 is connected to the discharge side of the exhaust vacuum pump vP during desorption operation, and easily adsorbed component gas is taken out of the system from this tank T2. . Also, this tank T2i, switching valve VAO
It is connected to the suction side of the blower for feeding the raw material through the t-. This switching valve VAOi, raw material gas and tank T2
This valve is used to select any of the easily adsorbed component gases, and is shown as a three-way valve in the figure. The same functionality can be obtained by opening and closing. The raw material gas or easily adsorbed component gas selected by this switching valve VAO is fed into either one of the adsorption towers C1 and C2 through one of the corresponding pulps VA1 and VA2. While the source gas is selected by the switching valve VAO, adsorption operations similar to those shown in FIG. 2 are performed in each adsorption tower CI and C2.

However, when one of the adsorption towers C1 and C2 enters the cleaning operation after the adsorption operation (while the other towers continue the desorption operation), the switching valve V
Switched from the AOU raw material gas side to the easily adsorbed component gas side,
This easily adsorbable component gas is fed into the adsorption tower during the cleaning operation through the same seven thread paths as the feeding line for the raw material gas.

As explained above, according to the present invention, cleaning gas is generated by using the thread path for feeding raw material gas to each adsorption tower. Since the structure is configured to supply cleaning gas, there is no need for a cleaning blower and no back pressure is applied to the exhaust pump, increasing the exhaust capacity.゛vN1゜VN2 and associated piping are no longer necessary, and the configuration can be simplified. Further, since the cleaning gas can be fed from the T2 tank to the tower being cleaned at a constant flow rate, there is also the advantage that the cleaning effect can be improved with a low violet gas. Although the above description has been made regarding the case of a two-tower system, the present invention can also be applied to an eight-tower system or more. That is, the fifth
6 shows a conventionally known example of a three-tower system, and FIG. 4 shows an example of an eight-tower system according to the present invention. Although the details are omitted, they have exactly the same effect as the present invention. Demeji and VN1~V
Three N3 valves and associated piping become unnecessary.

[Brief explanation of drawings]

1 and 4 are system diagrams of an adsorption device according to an embodiment of the present invention, and FIGS. 2, 8, 5, and 6 are system diagrams of conventional adsorption devices, respectively. CI, C2, C3...adsorption tower, B1...pl:
l'7, VP...Vacuum pump, T I, T2 knee pump, VAl, VA2゜VA3, VOl, VO
2, VO3, VDl, VD2゜VD 3, VS 2
, VS 6...7', VAo/9J valve exchange. Patent applicant: Industrial Development Research Institute (external link) Engraving of the drawings (no changes to the content) Figure 1 Heat 2 Figure 2 Easily adsorbed ingredients Kasrei 3 Figure 4 % 5 Figure Easily adsorbed ingredients n Suma 6 Illustration procedure amendment (Mr. 1)

Claims (1)

[Claims] In the gas adsorption separation method using the pressure fluctuation method, the operation of temporarily storing the desorbed gas in a gas tank, and the operation of feeding raw material for adsorption operation and feeding easily adsorbed component gas for cleaning operation from the gas tank using the same blower, A gas adsorption separation method characterized by: