JPH059124B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] In recent years, gas separation technology using energy-saving, space-saving, and inexpensive membranes has been widely used in many industrial fields including chemical industrial processes.
The membrane module uses hollow fibers.
There are three types: spiral and flat membrane, which are used depending on the purpose.

Compared to other methods, flat membranes are characterized by the ease of adjusting the membrane material and the ability to achieve the highest performance _. It is widely used in fields such as concentration. The present invention relates to a flat membrane gas separation device that is simple, inexpensive, and highly reliable and can be used at both reduced pressure and high pressure.

[Conventional technology]

An example of a gas separation device using a conventional laminated flat membrane module (Japanese Unexamined Patent Publication No. 61-93817) is shown in FIGS. 9 and 10.

FIG. 9 is an exploded explanatory view of one unit of the laminated flat membrane module, and FIG. 10 is a conceptual diagram of a gas separation apparatus using the module of FIG. 9.

The module shown in FIG. 9 has a supply gas chamber frame 1, a gas selective permeation membrane 2, a permeation gas chamber frame 3, a gas selective permeation membrane 2, and a supply gas chamber frame 1 stacked between an upper plate 9 and a lower plate 10. The whole thing is tightened.
A supply gas inlet 4 communicating with the frame is provided on one side of the supply gas chamber frame 1, and a supply gas outlet 5 is provided on the opposite side. . Further, a notch 7 independent of the inside of the frame is provided at the frame peripheral edge corresponding to the other side of the supply gas chamber frame 1 to serve as a flow path for the permeated gas. Permeation gas chamber frame 3
A similar notch 7 is provided at a position corresponding to the notch 7 of the supply gas chamber frame 1, and a permeate gas outlet is provided that communicates the inside of the permeate gas chamber frame 3 with the notch 7. 6 is provided. Further upper plate 9
is provided with a permeate gas extraction nozzle 11 for extracting the permeate gas collected from the notch 7 of each frame from the module.

The laminated flat membrane module 13 shown in FIG. 10 is made by laminating the required number of units shown in FIG. 9, and the side surfaces of the module except for the supply gas inlet and outlet are bonded together with an adhesive sealant. This module 13 has a gas supply box 28 arranged so as to face the supply gas inlet 4, and a fan 29 to supply gas to the inlet 4. A vacuum pump 30 is connected to the permeate gas extraction nozzle 11 of the module 13, and the permeate gas is sucked and collected.

[Problem that the invention seeks to solve]

In this type of gas separation device, the main reason for reducing the separation efficiency of the gas selective permeation membrane is concentration polarization at the membrane interface. Generally, at the membrane interface of the supply gas chamber, the gas composition of the supply gas chamber is polarized in concentration in a direction that suppresses the driving force for permeation due to the lack of easily permeable gas and the increase of poorly permeable gas. Further, the concentration of easily permeable gas decreases and the concentration of poorly permeable gas increases along the flow direction of the supply gas chamber, thereby forming a concentration gradient in the flow direction. Therefore, in order to eliminate concentration polarization and concentration gradients and improve membrane separation efficiency, a method has been adopted in which the flow rate of the supplied gas at the membrane interface is increased.

In the above-mentioned gas separation apparatus, in order to effectively recover oxygen-enriched gas from the air, a method is used in which a large flow rate of air is blown onto the module to increase the gas flow rate in the supply gas chamber. As described above, the above-mentioned gas separation device is effective for gas sources such as air, which exist inexhaustibly under atmospheric pressure, but is not suitable for gas sources that are limited in pressure or quantity. In particular, with conventional devices that pass through the module's supply gas chamber in one pass, if there are quantitative constraints on the gas source, it is not possible to sufficiently increase the gas flow rate at the membrane interface, resulting in a decrease in separation efficiency. Become. Furthermore, in conventional gas separation devices, both the permeated gas and the non-permeated gas are recovered at low pressures close to atmospheric pressure, so in order to supply the recovered gas to a process that requires high pressure, it is necessary to increase the pressure with a compressor. Furthermore, when high-pressure gas is introduced into the supply gas chamber of the module, the seal between the frame and the membrane must be made very strong; otherwise, the pressure inside the module will cause the module to bulge outward, causing the seal between the frame and the membrane to tighten. There is also the disadvantage that peeling occurs in the parts, leading to gas leakage and further damage to the module. Furthermore, the structure makes it difficult to adapt the gas separation device to changes in the amount of gas to be processed.

The present invention solves the above-mentioned problems and makes it easy to change the cross-sectional area of the supply gas chamber and the membrane area according to the amount of raw material gas while ensuring a high gas flow rate at the membrane interface. The present invention aims to provide a gas separation device that can efficiently separate any gas including:

[Means for solving problems]

The present invention covers the supply gas inlet and outlet of the laminated flat membrane module with a feed cover, and defines the number of supply gas chambers through which the supply gas flows in one pass, that is, the cross-sectional area of the supply gas flow path, according to the amount of the supply gas, By making the gas pass through the module multiple times, it was possible to increase the flow rate of the supplied gas at the membrane interface and expand the effective membrane area. In addition, by housing the module in a pressure vessel filled with pressurized gas, the seal part of the module is prevented from peeling and damage, reducing the need for a strict seal between the frame and membrane, and making it easier to handle high-pressure gas. This is a flat membrane type gas separation device.

That is, the present invention accommodates a permeated gas spacer in a frame, has a notch for taking out the permeated gas at the peripheral edge of the frame, and has a permeated gas outlet communicating with the notch from inside the frame. a permeable gas chamber frame; a gas selective permeable membrane; a supply gas chamber frame having supply gas inlets and inlets communicating with the outside of the frame at both ends of the frame, and having a notch at the periphery of the frame; a module is formed by laminating a large number of gas selective permeation membranes so as to be arranged between the supply gas chamber frame and the permeation gas chamber frame, and tightening this with an upper plate and a lower plate;
In a flat membrane type gas separation device having a laminated flat membrane module in which the cutout of the frame forms a permeate gas extraction flow path in the module and communicates with a permeate gas extraction nozzle provided on the upper plate;
The laminated flat membrane module is housed in a cylindrical pressure vessel filled with pressurized atmospheric gas, the supply gas inlet and outlet on the side of the module are covered with a feed cover, and the inside of the left and right feed covers is divided into two sections with partition plates of different heights.
dividing the supply gas flow within the module into a plurality of serial passes; connecting sections of the feed cover located at both ends of the passes to supply gas inlet pipes and outlet pipes extending outside the pressure vessel; This flat membrane type gas separation device is characterized in that the permeate gas extraction nozzle is connected to a permeate gas collection pipe extending outside the pressure vessel.

[Effect]

1 to 8 show specific examples of the flat membrane type gas separation apparatus of the present invention.

FIG. 1 is an exploded explanatory diagram of one example of the laminated flat membrane module of the present invention. In this module, a supply gas chamber frame 1, a gas selectively permeable membrane 2, a permeable gas chamber frame 3, a gas selectively permeable membrane 2, and a supplied gas chamber frame 1 are laminated between an upper plate 9 and a lower plate 10, and the entire structure is tightened. A large number of units consisting of a supply gas chamber frame, a gas selective permeation membrane, and a permeation gas chamber frame are stacked and used depending on the amount of gas to be processed. In the figure, solid lines indicate the flow of supply gas, and dotted lines indicate the flow of permeate gas. The supply gas chamber frame 1 is provided with a supply gas inlet 4 that communicates with the outside of the frame at one end of the frame, and a supply gas outlet 5 that similarly communicates with the outside of the frame at the other end, so that the supply gas flows in the direction of the solid arrow. do it like this. The supply gas inlets 4 and 5 may be made separately from the frame and fixed as shown in the figure, or openings may be made in the frame. In addition, it is preferable to have the supply gas flowing in from both sides and flowing out from both sides as shown in the figure in order to prevent the formation of dead spaces in the corners, but it is also possible to have one inlet and one outlet. The supply gas chamber frame 1 is provided with a notch 7 at a peripheral edge different from the supply gas inlets 4 and 5 to form a flow path for permeated gas. Notches 7 are also provided in the gas selective permeation membrane 2 and the permeation gas chamber frame 3 at the same locations.
As the gas selective permeation membrane, for example, a silicon membrane, a polysulfon-silicon membrane, a polyimide membrane, a cellulose acetate membrane, etc. can be used depending on the purpose. The permeable gas chamber frame 3 is provided with a permeable gas outlet 6 that accommodates a spacer 8 such as a net in the frame and communicates the notch 7 with the inside of the frame. In the figure, the permeated gas outlet 6 is provided only on the left side, but it can be similarly provided on the right side and the permeated gas can be recovered from both sides. In the figure, the flow of the supply gas and the flow of the permeate gas are in countercurrent flow through the membrane, but it is also possible to provide the permeate gas outlet 6 only on the right side so that the flows are in parallel flow. When the flow of the supply gas and the flow of the permeate gas are made countercurrent, it is possible to prevent a decrease in the partial pressure difference of the easily permeable gas at the membrane boundary. The permeate gas collected in the notch 7 from the permeate gas outlet 6 is recovered from the permeate gas take-off nozzle 11 provided on the upper plate 9 as indicated by the dotted arrow.

FIG. 2 is a perspective view of the laminated flat membrane module 13. The frame and membrane are bonded together using an adhesive sealant.
Adhesive sealants include epoxy, polyurethane,
A fluorine-based resin can be used, but is not limited thereto. A supply gas inlet 12 is opened on the side surface of the module, and a feed cover is brought into contact with this portion.

Figures 3 and 4 are perspective views of the feed cover.
This is used to pass the pass. These feed covers are in contact with the side of the module shown in Figure 2, and are housed in a cylindrical pressure vessel as shown in Figure 6, which will be described in detail below, and are formed by the side of the module and the inner wall of the pressure vessel. The shape is such that it can be accommodated in the space provided.

FIG. 3 shows a feed cover 14 for introducing supply gas, which is covered with a lid plate 18 except for the opening facing the supply gas inlet and outlet of the module, and both ends are covered with an end plate 18.
Closed at 7. The interior of the cover 14 is divided into upper and lower sections by a partition plate 15. Feed gas is introduced into the upper compartment via the inlet pipe 16 and flows into the feed gas chamber via the feed gas inlet of the module which abuts the compartment opening. At this time, the number of supply gas chambers is determined by the height of the partition plate 15, and the cross-sectional area of the first path flow path is determined by the number of supply gas chambers. The lower compartment opens to cover the inlets of the second and third pass supply gas chambers. Although the feed cover for non-permeable gas extraction is not shown,
It has the structure of FIG. 3 upside down. That is, the upper compartment is open to cover the inlets of the supply gas chambers of the first pass and the second pass, and the lower compartment is open to the outlet of the supply gas chamber of the third pass. The lower compartment is connected to an outlet pipe for taking non-permeable gas out of the module.

FIG. 4 shows a feed cover used to connect modules. The connecting feed cover 19 is closed at both ends with end plates 17, opened so as to face the supply gas inlets and outlets of both modules, and is covered at the center with a lid plate 18. Inside the feed cover 19 are two partition plates 15 for 3 passes.
Three compartments are formed, and the supply gas chambers of the respective paths can be communicated with each other, and solid arrows indicate the flow of the supply gas within the feed cover 19.

Figures 5 and 6 show a second
It is an overall view of a gas separation device in which two of the modules shown in the figure are inserted and a three-pass method is adopted. FIG. 5 is a front sectional view, and FIG. 6 is a view taken along arrow A in FIG.

First, looking at the relationship between the cylindrical pressure vessel 22, the module 13, and the feed covers 14, 19, and 24 in FIG. It is preferable that the feed cover is sized so that it is inscribed in the inner wall of the pressure vessel with a slight gap left behind, and the feed cover is preferably shaped to be formed by the inner wall of the pressure vessel and the side surface of the module. The feed covers 14, 19, and 24 are integrally fixed to both sides of the module 13 with fixing fittings 23.

Next, looking at the gas flow in FIG. 5, the supply gas indicated by the solid line enters the upper compartment of the feed cover 14 through the supply gas introduction pipe 16 that penetrates the side wall of the cylindrical pressure vessel 22, and enters the upper compartment of the compartment. The supply gas is introduced into a plurality of supply gas chambers through the supply gas inlet of the module that is in contact with the module, forming a first path. The supply gas of the first pass is introduced into the module 13 on the right side via the connecting feed cover 19, and is further reversed in the upper compartment of the feed cover 25 for introducing non-permeable gas, and is then transferred to the intermediate supply gas of the module 13 as a second pass. The gas passes through the supply gas chamber, reverses its direction again at the lower compartment of the feed cover 14 for introducing the supply gas, passes through the supply gas chamber at the lower part of the module 13 as a third pass, and finally becomes a non-permeable gas for deriving the non-permeate gas. are collected in the lower compartment of the feed cover 24,
It is taken out of the system through the outlet pipe 25. The gas that permeates through the gas selective permeation membrane while passing through the supply gas chamber passes through the cutout of the module as indicated by the dotted arrow, and is collected in the permeate gas take-out nozzle 1, and is collected in the collecting pipe 2.
0, recovered from the system through the collection tube 21.

FIG. 7 is a diagram showing the flow of gas when making four passes through one module 13. A feed cover 26 that connects the supply gas inlet pipe 16 and non-permeable gas outlet pipe 25 is in contact with the left end of the module 13, and two partition plates are installed inside the feed cover 26, with an upper compartment for the first pass and an intermediate compartment for the first pass. is used to reverse the feed gas from the second pass to the third pass, and the lower compartment is used for the fourth pass to exhaust non-permeate gas. In addition, one partition plate is installed inside the feed cover 27 at the right end, and each compartment is separated from the first pass to the second pass and the third pass.
It serves to reverse the flow of the supply gas from the pass to the fourth pass.

In this way, the feed cover has the functions of introducing, communicating, deriving, and reversing the supply gas, and by appropriately selecting the number and height of the partition plates inside the feed cover, the number of paths within the module can be changed. Depending on the number of supply gas chambers, the flow cross-sectional area of one pass can be determined. Therefore, it is possible to easily set the flow velocity in the supply gas chamber to a predetermined value for each gas source by replacing the feed cover. In addition, in order to cope with the reduction in the amount of gas in the supply gas chamber due to gas permeation through the gas selective permeation membrane, we reduced the number of supply gas chambers in the subsequent pass to increase the cross-sectional area of the flow path. Decreasing the flow rate and keeping it constant can be easily done by adjusting the height of the partition plate.

Figure 8 shows the linear velocity of the supply gas and the supply gas flow path disconnection when one module is (a) passed once, (b) passed three times, and (c) passed four times. FIG. 3 is a diagram shown to explain the relationship between areas. That is, when the sum of the cross-sectional areas of the supply gas chambers of the module is S (m ² ), and the sum of the membrane areas is A (m ² ), when a constant flow rate V (m ³ /hr) of supply gas is flowed in one pass, If the linear velocity in the supply gas chamber is v (m/hr), in the 3-pass method in (b), the sum of the cross-sectional areas of the supply gas chamber in one pass is 1/3 (m ³ ), and the supply gas V (m ³ /hr), the linear velocity of the gas in the supply gas chamber
V'(m/hr) is 3 of v(m/hr) in the first pass method.
double, making it possible to secure a high linear velocity.
On the other hand, in the case of the above three-pass method, this corresponds to three modules each having a membrane area of 1/3A arranged in series.
In this way, when one module with membrane area A is divided into multiple modules in series, the ratio of permeate gas flow rate to supply gas flow rate (stage cut) becomes smaller within each divided module. Therefore, higher separation performance can be obtained with the same membrane area. Also in the 4-pass method (c),
Similarly, the sum of the cross-sectional areas of the supply gas chambers for one pass is 1/4S
(m ² ), and the linear velocity v'' is four times v.

In addition, in order to expand the membrane area, two or more modules may be connected using a connecting feed cover as shown in FIG.

〔Example〕

Air separation was performed using the flat membrane type gas separation device of the present invention. The laminated flat membrane module is made by laminating 25 layers of the unit shown in FIG. 1 and using 50 polysulfon-fluorine gas selective permeation membranes (manufactured by Asahi Glass Co., Ltd.). The external dimensions of the module are 600 mm in height and 100 mm in width.
mm, height 100mm. Three such modules were connected and housed in a cylindrical pressure vessel. The total effective area of the membranes in the entire gas separation device was 5.1 m ² .
The experiment was conducted in one pass by replacing the feed cover.
A 3-pass method and a 5-pass method were used, and the results were compared.

For each method, the supply air is reduced to a pressure of 7
Kg/m ² G, flow rate 7 Nm ² /Hr, the inert gas nitrogen concentration was 95.2 vol% in the 1-pass method, while it was 97.6 vol% in the 3-pass method, 5
The pass method improved to 98.1%.

〔Effect of the invention〕

The present invention achieves the following effects by having a structure in which the following feed covers are appropriately selected and brought into contact with the laminated flat membrane module, and by housing the feed cover in a cylindrical pressure vessel filled with pressurized atmospheric gas. That is, (1) By selecting the number and height of the partition plates of the feed cover, one module can be used for multiple passes, and the number of supply gas chambers for one pass can be appropriately selected, that is, It has become possible to adjust the linear velocity of the gas flow in the supply gas chamber, and to ensure a predetermined high linear velocity for various gas sources.

(2) In addition, the number of supply gas chambers in the subsequent passes was reduced to ensure a high linear velocity for the gas flow in all passes.

(3) Multiple modules can be connected using a connecting feed cover to secure a predetermined membrane area.

(4) By housing the module in a pressurized atmospheric gas, the module can be easily sealed and can be easily used to process high-pressure gas.

[Brief explanation of the drawing]

1 to 8 are explanatory diagrams of the flat membrane type gas separation apparatus of the present invention, in which FIG. 1 is an exploded view of one unit of a laminated flat membrane module, FIG. 2 is a perspective view of the module, Fig. 3 is a perspective view of a feed cover for supply gas introduction, Fig. 4 is a perspective view of a connecting feed cover, and Fig. 5 is a three-pass type flat membrane gas separation device in which two modules are housed in a cylindrical pressure vessel. A front sectional view of FIG. 6 is a view taken in the direction of arrow A in FIG.
FIG. 7 is an explanatory diagram showing the flow of gas in the four-pass method, and FIG. 8 is an explanatory diagram comparing the one-pass method, the three-pass method, and the four-pass method. Figures 9 and 10
The figure is an explanatory diagram of a conventional flat membrane gas separation device.
FIG. 9 is an exploded view of one unit of the laminated flat membrane module, and FIG. 10 is a diagram for explaining the usage status of the gas separation device. 1... Supply gas chamber frame, 19... Connection feed cover, 2... Gas selective permeation membrane, 20... Permeated gas collection conduit, 3... Permeated gas chamber frame, 21... Permeated gas sampling pipe, 4... Supply gas inlet, 22... Cylindrical pressure vessel, 5... Non-permeable gas outlet, 23...
...Feed cover mounting fixture, 6...Permeate gas outlet, 24...Feed cover for non-permeable gas outlet, 7...Notch, 25...Non-permeate gas outlet pipe, 8...Spacer net, 26... Feed cover for gas introduction/input, 9... Upper plate, 27... End feed cover, 10... Lower plate, 28... Gas supply box, 11... Permeated gas extraction nozzle, 29... Fan, 12... Supply Gas inlet/outlet, 30... Vacuum pump, 13... Laminated flat membrane module, 14... Feed cover for supply gas introduction, 15... Partition plate, 16... Supply gas introduction pipe,
17... End plate, 18... Lid plate.

Claims (1)

[Claims] 1. A permeated gas spacer is housed in a frame, a notch for taking out the permeated gas is provided at the peripheral edge of the frame, and a permeated gas outlet is provided that communicates with the notch from within the frame. a permeable gas chamber frame having; a gas selective permeable membrane; a supply gas chamber frame having supply gas inlets and outlets communicating with the outside of the frame at both ends of the frame, and having a notch at the periphery of the frame; a module is formed by laminating a large number of gas selective permeation membranes arranged between the supply gas chamber frame and the permeation gas chamber frame, and tightening them with an upper plate and a lower plate; In a flat membrane type gas separation device using a laminated flat membrane module in which a permeate gas take-off flow path is formed in the module and communicated with a permeate gas take-off nozzle provided on the upper plate; The laminated flat membrane module is housed in a container filled with pressurized atmospheric gas, the supply gas inlet and outlet on the side of the module is covered with a feed cover, and the interior of the feed cover at both ends is divided into two or more sections with partition plates of different heights. to divide the feed gas flow within the module into a plurality of serial passes; sections of the feed cover located at both ends of the passes are connected to feed gas inlet pipes and outlet pipes extending outside the pressure vessel; A flat membrane gas separation device characterized by a nozzle connected to a permeate gas sampling pipe extending outside the pressure vessel. 2 A plurality of laminated flat membrane modules are housed in a straight line in a cylindrical pressure vessel, and the nearest supply gas inlet and outlet of adjacent modules are covered with one feed cover, and the feed cover is equipped with a partition plate corresponding to each path. 2. The flat membrane type gas separation device according to claim 1, wherein a plurality of permeate gas take-off nozzles are connected to the permeate gas collection pipe by communicating with each other through a collection conduit. 3. Claim 1, characterized in that the height of the partition plate of the feed cover is adjusted so that the cross-sectional area of the supply gas flow path of each pass in the laminated flat membrane module is reduced in accordance with the amount of permeated gas. Or the flat membrane gas separation device according to item 2.