JPS6130612B2 - - Google Patents

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention relates to a gas separation device for separating a mixed gas of a heavy component gas and a light component gas into a heavy component gas and a light component gas. The present invention relates to a gas separation device that can control.

[Technical Background of the Invention] Conventionally, a gas separation device is as shown in FIG.
A gas separation cascade 1 in which a plurality of separation element stages each having a plurality of gas separators connected in parallel are connected in series, a raw material supply system (not shown), and a gas separation cascade 1
a product piping 3 that connects between a product collection system (not shown) and the gas separation cascade 1; and a tail piping that connects the waste collection system (not shown) and the gas separation cascade 1. 4 and
It is composed of a feed control valve 5 provided in the middle of the feed pipe 2, a product control valve 6 provided in the middle of the product pipe 3, and a tail control valve 7 provided in the middle of the tail pipe 4.

In this gas separation apparatus, a mixed gas of a light component gas and a heavy component gas, which is a gas to be separated, is supplied from a raw material supply system and introduced into a gas separation cascade 1 through a feed pipe 2.

As shown in FIG. 1b, the gas to be separated is successively separated in the separation element stages 8 in the gas separation cascade 1, and the light component gas, whose temperature has been increased, is sent as a product gas to the product piping 3, 3a to the product collection system, and the gas with a reduced concentration of light component gas is collected as waste gas through the tail pipe 4 to the waste collection system.

In a gas separation device, when changing the concentration of light component gases in product gas and waste gas, the amount of gas to be separated can be adjusted using flow control valves 5, 6, and 7 installed in feed piping 2, product piping 3, and tail piping 4. By adjusting the product gas and waste gas flow rates, the concentration of light component gas in the product gas and the concentration of light component gas in the waste gas were controlled. FIG. 1b shows the piping connection of an optional separation element stage 8, 8a in the gas separation cascade 1. FIG.

That is, the separation element stage indicated by the reference numeral 8a is a bottom stage, and any separation element stage 8 and bottom stage 8a
A feed pipe 2a, a product pipe 3a, and a tail pipe 4a are connected to the bottom stage 8a, and the separated gas is collected in the product collection system and waste product collection system in order. It is connected to the tail pipe 4.

[Problems in the Background Art] In the above device, the flow rate of the gas to be separated supplied to the gas separation cascade 1 is F, the concentration of light component gas in the gas to be separated is X _F , and the product concentrated and separated in the gas separation cascade 1 is If the gas flow rate is _P , the _{concentration} of light component gas in the product gas is Equation (1) is obtained by balancing the amount of light component gas entering and exiting the cascade 1.

F·X _F =P·X _P +T·X _T (1) Equations (2) and (3) are obtained by transforming equation (1).

X _P = (F・X _{F −T}・X _{T ) /} P…(2) Considering the case of changing the flow rate P of the product gas, if the flow rate P of the product gas is increased, the denominator of equation ( ₂ ) increases, so the concentration of light component gas in the product gas When the gas flow rate P is decreased, the denominator of equation (2) becomes smaller, so the concentration X _P of light component gas in the product gas becomes larger. Similarly, when the flow rate T of the waste gas is changed by adjusting the flow rate control valve, when the flow rate T of the waste gas is changed, the concentration of light component gas in the waste gas changes according to equation (3).

By the way, Equation (4) can be obtained from the balance of gas flowing in and out of the gas separation cascade 1, and Equation (5) can be obtained from the relationship between Equation (1) and Equation (4).

F=P+T …(4) T/P=(X _P −X _F )/(X _F −X _T ) …(5) For example, in a gas separation cascade where the value of T/P in equation (5) is about 10 In one case, the waste gas flow rate T is 10 times the product gas flow rate P. Therefore,
Comparing the case where the waste gas flow rate and the product gas flow rate are changed by the same flow rate, the change in the concentration of light component gas in the waste gas obtained from equation (3) is equal to the change in the concentration of light component gas in the product gas obtained from equation (2). of the change in the concentration of light component gases
The value is 1/10. If the product gas flow rate and the waste gas flow rate are changed too much, the gas flow rate distribution within the gas separation cascade 1 will collapse and separation loss will increase.
There is a limit to the amount by which the product gas flow rate and waste gas flow rate can be changed, and the control range for the concentration of light component gas in the waste gas is generally narrower than the control range for the concentration of light component gas in the product gas.

[Object of the Invention] The present invention has been made to solve the problems of the background art described above, and it is possible to increase the flexibility of production by widening the concentration control range of the gas separation cascade, thereby reducing the concentration of waste products. An object of the present invention is to provide a gas separation device that can be controlled to an optimum value and economically operated.

[Summary of the Invention] That is, the present invention provides a gas separation cascade in which a plurality of separation element stages formed by connecting a plurality of gas separators in parallel are connected in series, and a gas to be separated is supplied to the gas separation cascade. feed piping and
A product pipe that collects the product gas that has been concentrated and separated in the gas separation cascade, a tail pipe that collects the waste gas that has been depleted and separated in the gas separation cascade, and a product pipe that collects the product gas that has been separated and concentrated in the gas separation cascade; A gas consisting of a bypass pipe that connects any one of the three or two separation element header pipes forming a separation element stage, and a flow rate control valve that adjusts the amount of gas flowing through the bypass pipe. It is a separation device. Further, in the above separation device, a plurality of gas separators are connected in parallel and the gas to be separated is passed through an integrated field pipe that supplies the gas to be separated to the feed pipe of each of the gas separation cascades, and a product pipe of the plurality of gas separation cascades for concentration. integrated product piping that collectively collects the separated product gas; integrated tail piping that collectively collects the depleted and separated waste gas that passes through the tail piping of the plurality of gas separation cascades; 3 forming any separation element stage of
Either 1 or 2 separation element header piping
This gas separation device is characterized by having an integrated bypass pipe that collects bypass pipes led out from header pipes and connects them to an integrated tail pipe, and a flow rate control valve provided on the integrated bypass pipe.

[Embodiments of the Invention] Examples of the gas separation apparatus according to the present invention will be described below with reference to FIGS. 2 and 3.

FIG. 2 shows a first embodiment of the invention.

That is, in FIG. 2a, the gas separation cascade 1 is connected to a raw material supply system (not shown) via a feed pipe 2, similar to the separation device shown in FIG. It is connected to a product collection system (not shown), and is connected via a tail pipe 4 to a waste collection system (not shown).
Further, a feed control valve 5 is installed in the middle of the feed pipe 2, a product control valve 6 is installed in the middle of the product pipe 3, and a tail control valve 7 is installed in the middle of the tail pipe 4.

Here, in the present invention, one of the three or two separation element header pipes 11 of any separation element stage 8 in the gas separation cascade 1 and the tail pipe 4, as shown in FIG. A bypass pipe 9 connects between the two, and a bypass control valve 10 is installed in the middle of the bypass pipe 9.

FIG. 2b shows the details of the vicinity of the bypass piping 9.
One end of the bypass pipe 9 is connected, and the other end of the bypass pipe 9 is connected to the tail pipe 4.

Next, the operation of this gas separation device will be explained.

Gas to be separated supplied from the raw material supply system is introduced into the gas separation cascade 1 through the feed pipe 2. The gas to be separated is sequentially separated in each separation element stage 8 in the gas separation cascade 1, and is discharged from the gas separation cascade 1 as a concentrated and separated product gas and a depleted and separated waste gas. Product gas is collected into the product collection system through product piping 3,
The waste gas is collected through the tail pipe 4 into the waste collection system. When the bypass control valve 10 is closed, gas does not flow into the bypass pipe 9, so the first
The operating state is the same as that of the conventional gas separation device shown in the figure.

That is, the feed control valve 5, product control valve 6, and tail control valve 7 are adjusted to control the concentration of light component gas in the product gas and the concentration of light component gas in the waste gas.

In the present invention, when the optimum concentration of light gas in the waste gas exceeds the range that can be controlled by adjusting the three control valves described above, the bypass control valve 10 is opened;
By adjusting this bypass control valve 10, gas with a high concentration of light component gas flowing through the separation element header piping 11 of the separation element stage 8 in the gas separation cascade 1 flows into the tail piping 4 through the bypass piping 9. The concentration of light component gases in the gas can be increased. By adjusting the bypass control valve 10 to adjust the flow rate of the gas flowing through the bypass pipe 9, the concentration of the light component gas of the waste gas can be continuously changed.

For example, if the upper limit of the concentration of light component gas in the waste gas obtained by making full use of the three control valves described above is set to Xt ₂ , then If the concentration in the component gas is Xb, the flow rate of the gas flowing through the bypass pipe 9 is Qb, and the flow rate of the gas flowing through the tail pipe 4 before merging with the gas flow flowing through the bypass pipe 9 is Qt, then the light component gas The concentration of light component gas in the gas obtained by combining the gas with concentration Xt ₂ and the gas with light component gas concentration _Xb in the tail pipe 4
is given by equation (6).

X′t ₂ = (Xt ₂・Qt+Xb・Qb) / (Qt+Qb) …(6) Since Xb>Xt ₂ , X′t ₂ >Xt ₂ .

Therefore, the upper limit of the concentration of light component gases in the waste gas that can be controlled increases to X′t ₂ compared to the conventional device controlled by three regulating valves. X′t ₂ changes depending on the value of Xb and also changes depending on the gas flow rate Qb of the bypass pipe 9. Therefore, by adjusting the bypass control valve 10 to change Qb, X't ₂ can be changed continuously, and the control range of the concentration of light component gas in the waste gas is expanded.

FIG. 3 is a flow diagram showing a second embodiment of the present invention.

In the embodiment shown in FIG. 3, a plurality of gas separation cascades 1 (three sets in the figure, but not limited to this) are connected in parallel, and each gas separation cascade is connected to the integrated feed pipe 12 that supplies the gas to be separated. 1
A feed pipe 2 is connected to the feed pipe 2. Further, the product pipe 3 of each gas separation cascade 1 is connected to an integrated product pipe 13, and the tail pipe 4 of each gas separation cascade 1 is connected to an integrated tail pipe 14.

The bypass piping 9 of each gas separation cascade 1 shown in the first embodiment is connected to each gas separation cascade 1.
Integrated bypass piping 15 without connecting to the tail piping 4 of
The other end of the integrated bypass pipe 15 is connected to the integrated tail pipe 14. In addition, integrated feed piping 12, integrated product piping 1
3. Integrated tail piping 14, integrated bypass piping 15
A feed control valve 5, a product control valve 6, a tail control valve 7, and a bypass control valve 10 are installed in the middle of the
is connected. The control range of the concentration of light component gases in the waste gas is expanded not only in the case of a single cascade but also in the case where a plurality of gas separation cascades are connected in parallel in this way.

[Effects of the Invention] As explained above, the present invention is a gas separation device in which a bypass pipe having a bypass control valve is provided between the feed pipe and the waist pipe in the bottom stage of the separation element stages. Therefore, the bypass control valve is kept fully closed in the concentration range that can be handled by normal cascade control, but when it becomes necessary to operate at a high waste concentration that cannot be handled by normal cascade control, in other words, the tail control valve is left fully open. If the waste gas concentration cannot be controlled to the target waste gas concentration, the bypass control valve can be adjusted to accommodate changes in the optimal product gas concentration and waste gas concentration due to various changes in the situation.

Therefore, the controllable range of the concentration of light component gases in the waste gas is expanded, and the gas separation device can always be operated in an appropriate state.

[Brief explanation of the drawing]

Fig. 1a is a flow diagram showing a conventional gas separation device, Fig. 1b is a flow diagram of the separation element stage of Fig. 1a, and Fig. 2a is a flow diagram showing a first embodiment of the present invention. FIG. 2b is a flow diagram of the separating element stage of FIG. 2a, and FIG. 3 is a flow diagram showing a second embodiment of the invention. 1... Gas separation cascade, 2... Feed piping, 3... Product piping, 4... Tail piping,
5...Feed control valve, 6...Product control valve, 7...Tail control valve, 8...Separation element stage, 9
...Bypass piping, 10...Bypass control valve, 1
1...Separation element header piping, 12...Integrated feed piping, 13...Integrated product piping, 14...
Integrated tail piping, 15...Integrated bypass piping.

Claims (1)

[Claims] 1. A gas separation cascade in which a plurality of separation element stages formed by connecting a plurality of gas separators in parallel are connected in series, and a feed pipe that supplies gas to be separated to the gas separation cascade. , a product piping that collects the product gas concentrated and separated in the gas separation cascade, a tail piping that collects the waste gas depleted and separated in the gas separation cascade, and this tail piping and any part of the gas separation cascade. A bypass pipe that connects to any one of the three or two separation element header pipes forming the separation element stage, and a flow rate control valve that adjusts the amount of gas flowing through the bypass pipe. A gas separation device featuring: 2 A plurality of gas separation cascades in which separation element stages formed by connecting a plurality of gas separators in parallel are connected in parallel, and a plurality of gas separation cascades are connected in parallel, and the gas to be separated is connected to the feed piping of the gas separation cascade. integrated field piping that supplies gas, integrated product piping that collectively collects the concentrated and separated product gas that passes through the product piping of the plurality of gas separation cascades, and depleted and separated product gas that passes through the tail piping of the plurality of gas separation cascades. integrated tail piping that collectively collects waste product gas; and a bypass led out from one of the three or two separation element header pipings forming any separation element stage in the plurality of gas separation cascades. A gas separation device comprising: an integrated bypass pipe that collects pipes and connects them to an integrated tail pipe; and a flow rate control valve provided on the integrated bypass pipe.