JP6500499B2 - Separation membrane module and method of operating the same - Google Patents

Description

  The present invention relates to a separation membrane module used to separate some components from a fluid such as a solution or a mixed gas, and a method of operating the same.

  A separation membrane module is known as an apparatus for separating components in a solution or mixed gas. The tubular separation membrane used for the separation membrane module has a tubular porous ceramic support and a porous separation membrane made of zeolite or the like provided on the outer peripheral surface of the support. In order to separate a specific component from a fluid such as a solution or mixed gas, the fluid of the solution is brought into contact with one of the separation membrane elements (the outer surface) and the other (the inner surface) is depressurized to separate the specific component. A method of vaporizing and separating, a method of vaporizing a solution to bring it into contact with a separation membrane in a gaseous state, reducing the pressure on the non-contact side to separate specific components, or bringing a mixed gas under pressure into contact with the separation membrane Methods for separating specific components are known (Patent Documents 1 and 2).

  When water adheres to the zeolite membrane, the separation performance of the zeolite membrane is reduced. Patent Document 3 describes that the condensation of steam at start-up is prevented by heating the zeolite membrane with an electric heater.

JP, 2013-39546, A JP, 2011-152507, A JP, 2009-39654, A

  According to the separation membrane module of Patent Document 3, the water attached to the zeolite membrane can be removed by heating the zeolite membrane with an electric heater, that is, the zeolite membrane can be dried.

  However, in patent document 3, it becomes necessary to install an electric heater along all the tubular zeolite membranes, and it becomes expensive. In addition, work such as inspection and repair of the zeolite membrane becomes extremely troublesome.

  An object of the present invention is to provide a separation membrane module capable of drying the separation membrane extremely easily, and an operation method thereof.

  The separation membrane module of the present invention has a housing and a separation membrane disposed in the housing, and the separation membrane module is supplied with the fluid to be treated and from which the fluid having permeated the separation membrane is taken out. It is characterized in that it comprises a separation membrane drying means for supplying a drying gas mainly composed of a sexing gas into the separation membrane module.

  In one aspect of the present invention, the separation membrane is a zeolite membrane, and the drying gas is mainly composed of carbon dioxide gas.

  The membrane drying method of the separation membrane module of the present invention is an operation method of the separation membrane module, wherein the separation membrane is dried by the drying gas when the separation membrane module is activated. In addition, it is preferable to dehydrate the to-be-processed gas after starting.

  In the separation membrane module of the present invention, a drying gas mainly composed of a separation membrane permeable gas is supplied into the separation membrane module to dry the separation membrane. The separation membrane permeable gas permeates the separation membrane, whereby the water adhering to the separation membrane is removed from the separation membrane along with the permeation gas, and the separation membrane is dried. This improves the separation performance of the separation membrane.

  The membrane drying process is preferably performed when the separation membrane module is activated, but may be performed during operation. During operation, it is preferable to prevent adhesion of water to the separation membrane by dehydrating the gas to be treated supplied to the separation membrane module.

It is sectional drawing which follows the housing axial center line direction of the main-body part of the separation-membrane module which concerns on embodiment. It is the II-II sectional view taken on the line of FIG. It is the III-III sectional view taken on the line of FIG. It is an expanded sectional view of an end pipe and a support plate. It is a flowchart of a separation membrane module.

  A separation membrane module according to an embodiment of the present invention will be described with reference to FIGS.

  The separation membrane module 1 includes a cylindrical housing 2 whose vertical direction is a cylinder axial direction, and a plurality of tubular separation membranes (zeolite membranes in this embodiment) 3 arranged in a direction parallel to the axial center line of the housing 2. A support plate 5 provided at the lower part in the housing 2, a bottom cover 6A attached to the lower end of the housing 2 and a top cover 6B attached to the upper end, and a lower part in the housing 2 parallel to the support plate 5 It has a first baffle (straightening plate) 7 and a second baffle (straightening plate) 8 and the like respectively disposed in the upper part. The first baffle 7 is disposed on the upper side of the support plate 5.

  In this embodiment, outward facing flanges 2a, 2b, 6b and 6c are provided on the lower end and upper end side of the housing 2 and the outer peripheral edge of the bottom cover 6A and the top cover 6B, respectively, which are fixed by bolts (not shown). It is done. The peripheral edge portion of the support plate 5 is supported by a support seat 2 t provided around the inner peripheral surface of the housing 2. A seal member is interposed between the lower surface outer peripheral portion of the support plate 5 and the upper surface of the support seat 2t.

  In this embodiment, the end pipe 4 is connected to the lower end of the tubular separation membrane 3, and the end plug 20 is connected to the upper end of the tubular separation membrane 3. Although only seven tubular separation membranes are shown in FIGS. 1 to 3, in practice, a large number of tubular separation membranes are provided as shown in FIG. 4. In addition, a tubular separation membrane connected body in which two or more tubular separation membranes 3 are connected by a joint pipe (not shown) may be used.

  An inlet 9 for the fluid to be treated is provided on the outer peripheral surface of the lower portion of the housing 2, and an outlet 10 for the non-permeate fluid is provided on the outer peripheral surface of the upper portion. The inlet 9 is provided to face the chamber 11 between the support plate 5 and the first baffle 7. The outlet 10 is provided to face the upper chamber 12 of the second baffle 8. Between the baffles 7 and 8 is a main chamber 13 for performing membrane separation.

  A plurality of rods 14 are erected from the support plate 5 at the bottom, and the baffles 7 and 8 are supported by the rods 14. A male screw is engraved at the lower end of the rod 14 and screwed into the female screw hole of the support plate 5. The baffles 7 and 8 are supported at a predetermined height by sheaths 14A and 14B (FIG. 4) fitted on the rod 14. The sheath 14 A is disposed between the support plate 5 and the baffle 7. The sheath 14 B is disposed between the baffles 7 and 8. The baffle 8 is mounted on the upper end surface of the sheath tube 14 B, and is fixed by a nut screwed to the upper end of the rod 14. The number of baffles is not limited to this embodiment, and three or more baffles may be used.

  Between the outer peripheral surface of the baffles 7 and 8 and the inner peripheral surface of the housing 2, a sealing member such as an O-ring, a V-packing, or a C-ring may be interposed.

  Each of the baffles 7 and 8 is provided with circular insertion holes 7a and 8a for inserting the tubular separation membrane 3, and a combination of the tubular separation membrane 3, the end pipe 4 and the end plug 20 is provided for each insertion hole 7a. , 8a. The bores of the insertion holes 7a and 8a are larger than the diameters (outer diameters) of the tubular separation membrane 3, the end pipe 4 and the end plug 20, and the inner peripheral surfaces of the insertion holes 7a and 8a, the end pipe 4 and the end plug 20 There is a gap over the entire circumference with the outer circumferential surface.

  On the upper surface side of the support plate 5, an insertion hole 5a into which the lower end of the end pipe 4 connected to the tubular separation membrane 3 is inserted is provided. The insertion hole 5 a has a cylindrical shape, and extends from the upper surface of the support plate 5 to a middle in the thickness direction. The bottom of the insertion hole 5a faces the outflow chamber 16 below the support plate 5 through the small hole 5b and the large hole 5c.

  The bore 4a of each end tube 4 communicates with the outflow chamber 16 between the bottom cover 6A and the support plate 5 via the small hole 5b and the large hole 5c. The bottom cover 6A is provided with an outlet 6a for the separated permeated fluid.

  Although illustration is omitted, a groove is provided around the outer peripheral surface of the end pipe 4 in the vicinity of the lower end, and an O-ring made of fluorine rubber, fluorine resin or the like is attached. Further, a groove concentric with the tube hole 4a of the end tube 4 is provided around the lower end surface of the end tube 4 and an O-ring is mounted. A seal between the outer surface of the end pipe 4 and the insertion hole 5a is performed by bringing the O-rings into close contact with the inner peripheral surface of the insertion hole and the bottom of the insertion hole 5a. Only one of the O-ring on the outer peripheral surface of the end pipe 4 and the O-ring on the lower end surface may be provided.

  As shown in FIG. 5, the upper end of the end tube 4 is a small diameter portion 4 g and is inserted into the lower portion of the tubular separation membrane 3. An O-ring is attached to a groove provided on the outer peripheral surface of the small diameter portion 4g. An O-ring is also interposed between the lower end surface of the tubular separation membrane 3 and the stepped surface of the end pipe 4. The connection between the end pipe 4 and the tubular separation membrane 3 may be sealed by using a heat-shrinkable tube without using the O-ring as described above, and further using a heat-shrinkable tube in addition to using an O-ring. You may use.

  An end plug 20 is connected to the upper end of the tubular separation membrane 3. The end plug 20 has a cylindrical shape or a shape obtained by shaving a part of the end plug 20 and seals the upper end of the tubular separation membrane 3. At the lower end of the end plug 20, a small diameter portion inserted into the tubular separation membrane 3 is provided. The end plug 20 and the tubular separation membrane 3 are sealed by an O-ring. Further, the end plug 20 and the tubular separation membrane 3 may be sealed by using a heat shrinkable tube without using an O-ring, or a heat shrinkable tube may be further used after using the O-ring.

  In order to reduce the weight of the end plug 20, a recess 20v is recessed from the upper end surface of the end plug 20. A drain hole may be provided to communicate the bottom of the recess 20v with the side peripheral surface of the end plug 20.

  In this embodiment, since the end plug 20 is disposed on the upper end side of the tubular separation membrane 3, the load is applied in such a direction that the end faces thereof are pressed against the tubular separation membrane 3, the end plug 20 and the end pipe 4. It is over.

  However, in the present invention, the end pipe 4 and the support plate 5 may be disposed on the upper end side of the tubular separation membrane 3 and the end plug 20 may be disposed on the lower end side of the tubular separation membrane 3. In this case, by providing a biasing member such as a spring for biasing the end plug 20 upward, the end faces of the tubular separation membrane 3, the end plug 20, and the end pipe 4 are pressed against each other. It is preferred to apply a load.

  In this embodiment, the lower end portion of the end pipe 4 of the combination of the tubular separation membrane 3, the end pipe 4 and the end plug 20 is inserted into the insertion hole 5 a provided in the support plate 5 to form the tubular separation membrane 3, the end A connection of the pipe 4 and the end plug 20 is erected on the support plate 5. Only by inserting the lower end portion of the end pipe 4 into the insertion hole 5a, the end pipe 4 and the support plate 5 can be easily connected in an airtight or liquid tight manner. Further, since the insertion hole 5a is cylindrical, the work of forming the insertion hole 5a in the support plate 5 is easy, and the manufacture of the support plate 5 is also easy. Therefore, the production period of the separation membrane module can be shortened and the production cost can be reduced.

  In order to dry the tubular separation membrane 3, the separation membrane module 1 is provided in the housing 2 with a means for supplying a drying gas mainly composed of a separation membrane permeable gas.

  FIG. 5 is a flow chart showing an example thereof. A supply pipe 30 of the process gas which has passed through the steam separator 29 is connected to the inflow port 9 and a valve 31 is provided. A nonpermeate fluid outlet pipe 40 is connected to the nonpermeate fluid outlet 10, and a valve 41 is provided. A permeated fluid outlet pipe 50 is connected to the permeated fluid outlet 6 a, and a valve 51 is provided. On the upstream side of the valve 51, the separation pipe 52 branches from the pipe 50 and is connected to the inlet of the reservoir tank 55 via the valve 53 and the pressure pump 54. The outlet of the reservoir tank 55 is connected downstream of the valve 31 in the pipe 30 via the pipe 56 and the valves 57 and 58. A carbon dioxide gas cylinder 60 is connected between the valves 57 and 58 of the pipe 56 via the pipe 61 and the valve 62.

  In the separation membrane module 1 configured as described above, during normal operation, the valves 31, 41 and 51 are opened and the valves 53, 57, 58 and 62 are closed. The fluid to be treated is removed of water vapor by the water vapor adsorber 29 and introduced into the chamber 11 of the housing 2 through the pipe 30 and the inlet 9, and the inner peripheral surface of the insertion hole 7 a of the baffle 7 and the end pipe 4 After flowing into the main chamber 13 through the gap between the outer peripheral surface and through the main chamber 13, it flows into the chamber 12 through the gap between the insertion hole 8 a of the baffle 8 and the end plug 20. While flowing through the main chamber 13, a part of the component of the fluid to be treated permeates through the tubular separation membrane 3 and flows out of the tubular separation membrane 3 into the pipe 50 through the outflow chamber 16 and the outlet 6 a. The fluid that has not permeated flows out of the outlet 10 into the pipe 40.

  In this embodiment, the gas to be treated contains carbon dioxide gas. The carbon dioxide gas passes through the zeolite tubular separation membrane 3, and a gas containing carbon dioxide gas as the main component flows into the pipe 50.

  At an appropriate time of operation, the valve 53 is opened and the pump 54 is operated to pressurize the gas mainly containing carbon dioxide gas and introduce it into the reservoir tank 55. After the pressure in the reservoir tank 55 reaches a specified pressure, the valve 53 is closed, the pump 54 is stopped, and the gas mainly composed of carbon dioxide is stored in the reservoir tank 55. It is desirable to set the pressure to usually 0.1 MPaG or more and 1.0 MPaG or less. Although there is no restriction in the pump for pressure increase, it is preferable to use a pump which does not mix foreign matter and oil.

  When the separation membrane module 1 is activated, the valves 51, 57, 58 are opened, the valves 31, 41 are closed, and a gas mainly composed of carbon dioxide in the reservoir tank 55 is supplied into the housing 2. As a result, carbon dioxide gas in the gas passes through the zeolite tubular separation membrane 3 to remove the attached water. That is, the water adhering to the separation membrane 3 is rapidly removed from the separation membrane 3 by evaporating by the carbon dioxide gas flow passing through the separation membrane 3 or moving to the secondary side of the membrane, and the separation membrane Is dried and the separation performance is recovered. Alternatively, the valves 57, 58, 59 may be opened, the valves 31, 41, 51 may be closed, and carbon dioxide gas that contains a large amount of water through the membrane may be purged from the valve 59 to the atmosphere. The completion of the drying may be managed by the supply time of carbon dioxide gas, or by measuring the water concentration in the permeated gas and confirming it as the specified value or less. In addition, the gas supplied to the separation membrane 3 at the time of drying can be further promoted to be dried by heating by the heater 70. The gas temperature on the heater outlet side is usually 20 ° C. or more, desirably 35 ° C. or more, and more preferably 50 ° C. or more.

  When the gas mainly containing carbon dioxide gas is not stored in the reservoir tank 55, the carbon dioxide gas is supplied from the carbon dioxide gas cylinder 60 into the housing 2 to dry the separation membrane 3. After drying of the separation membrane 3 is completed, the operation shifts to the normal operation.

  The flow in the main chamber 13 and the flow in the tubular separation membrane 3 may be either cocurrent or countercurrent, and the inlet 9 and the outlet 10 of the fluid to be treated may be interchanged.

  The separation membrane module 1 may be used with the top cover 6B side up as shown in FIG. 1 or may be used with the bottom cover 6A side up. In addition, the separation membrane module 1 may be installed horizontally so that the direction in which the bottom cover 6A and the top cover 6B are connected is substantially horizontal.

  In this embodiment, a large number of tubular separation membranes 3 are arranged in parallel, and the membrane area is large, so that the membrane separation is efficiently performed.

  In this embodiment, end pipes 4 and end plugs 20 connected to upper and lower ends of the tubular separation membrane 3 are inserted into the insertion holes 7a and 8a of the baffles 7 and 8, respectively. Therefore, even if the tubular separation membrane 3 vibrates or swings and the end pipe 4 and the end plug 20 abut against the inner peripheral surfaces of the insertion holes 7a and 8a, the zeolite membrane is not damaged, and the stable operation can be performed for a long time It can be performed.

  The separation membrane modules of the present invention can be used in connection according to the amount of fluid, or the desired degree of separation and concentration. Connect the piping so that the fluid from the outlet will enter the inlet of another module if the fluid volume is high or if the desired degree of separation / concentration is too high to process in one module Is preferred. Further, they may be further linked according to the degree of separation and the degree of concentration to obtain the desired degree of separation and degree of concentration.

  The separation membrane modules of the present invention may be installed in parallel to branch the fluid and supply the gas. At this time, it is also possible to install modules in series in respective modules in parallel. When modules in parallel are connected in series, the amount of supplied gas is reduced in the serial direction and the linear velocity is reduced. Therefore, it is preferable to reduce the number of parallel installation so as to maintain the linear velocity appropriately.

  In the case of arranging the modules in series, the permeated components may be discharged for each module, or may be connected and gathered between the modules and discharged.

  Hereinafter, suitable materials and the like of each member constituting the separation membrane module of the present invention will be described.

  As the steam separator 29, one in which a steam absorbent such as zeolite or silica gel is contained in a casing is preferable, but a condenser that condenses the steam by a cooling method can also be used.

  Examples of the material of the end pipe 4 and the end plug 20 include metals, ceramics, resins, and the like that do not allow fluid to permeate, but are not limited thereto. The material of the baffles 7 and 8 and the joint tube 17 is usually a metal material such as stainless steel, but it is not particularly limited as long as it has resistance to heat resistance and supply and permeation components under separation conditions. It is possible to change to other materials.

  The tubular separation membrane 3 preferably has a tubular porous support and a zeolite membrane as an inorganic separation membrane formed on the outer peripheral surface of the porous support. The material of the tubular porous support is an inorganic porous material of a sintered ceramic or sintered metal containing silica, α-alumina, γ-alumina, mullite, zirconia, titania, yttria, silicon nitride, silicon carbide and the like. Quality supports. Among them, an inorganic porous support containing at least one of alumina, silica and mullite is preferable. The average pore diameter of the surface of the porous support is not particularly limited, but preferably the pore diameter is controlled, usually 0.02 μm or more, preferably 0.05 μm or more, and more preferably 0.1 μm. The range is usually 20 μm or less, preferably 10 μm or less, and more preferably 5 μm or less.

The zeolite is crystallized on the surface of the porous support to form a zeolite membrane.
The main zeolite constituting the zeolite membrane usually comprises a zeolite having an oxygen 6-10 membered ring structure, and preferably comprises a zeolite having an oxygen 6-8 membered ring structure.

  Here, the value of n of the zeolite having an oxygen n-membered ring indicates the largest number of oxygen among the pores forming the zeolite skeleton and the element T. For example, when a pore of an oxygen 12-membered ring and an 8-membered ring is present as in the case of MOR-type zeolite, it is regarded as a zeolite of oxygen 12-membered ring.

  Examples of zeolites having an oxygen 6-10 member ring structure include AEI, AEL, AFG, ANA, BRE, CAS, CDO, CHA, DAC, DDR, DOH, EAB, EPI, ESV, EUO, FAR, FRA, FER, GIS, GIU, GOO, HEU, IMF, ITE, ITH, KFI, LEV, LIO, LOS, LTN, MAR, MEP, MER, MEL, MFI, MFS, MON, MSO, MTF, MTN, MTT, MWW, NAT, NES, PON, PAU, RHO, RRO, RTE, RTH, RUT, SGT, SGT, SOD, STF, STI, STT, TER, TOL, TON, TSC, TUN, UFI, VNI, VSV, WEI, YUG, etc. There is.

  Even if the zeolite membrane is a single zeolite membrane or the zeolite powder is dispersed in a binder such as a polymer to form a membrane, the zeolite is fixed in a film on various supports. It may be a zeolite membrane complex. The zeolite membrane may partially contain an amorphous component and the like.

  The thickness of the zeolite membrane is not particularly limited, but is usually 0.1 μm or more, preferably 0.6 μm or more, and more preferably 1.0 μm or more. Also, it is usually 100 μm or less, preferably 60 μm or less, and more preferably 20 μm or less.

  However, in the present invention, a tubular separation membrane having a separation membrane other than the zeolite membrane may be used.

  The outer diameter of the tubular separation membrane 3 is preferably 3 mm or more, more preferably 6 mm or more, still more preferably 10 mm or more, preferably 20 mm or less, more preferably 18 mm or less, still more preferably 16 mm or less. When the outer diameter is too small, the strength of the tubular separation membrane may not be sufficient and may be easily broken, and when it is too large, the membrane area per module decreases.

  The length of the portion of the tubular separation membrane 3 covered with the zeolite membrane is preferably 20 cm or more, preferably 200 cm or less.

  In the separation membrane module of the present invention, the tubular separation membrane may be a single-tubular type or a multi-tubular type, and usually 1 to 3,000, particularly 50 to 1,500, are disposed, and the shortest distance between tubular separation membranes is 2 mm to 10 mm. It is preferable to arrange so that The size of the housing and the number of tubular separation membranes are appropriately changed according to the amount of fluid to be treated. The tubular separation membranes may not be connected by the joint pipe 17.

  In the separation membrane module of the present invention, the treatment fluid to be separated or concentrated is not particularly limited as long as it is a mixture of gas or liquid composed of a plurality of components that can be separated or concentrated by the separation membrane, and any mixture Although it may be, it is preferable to use for the mixture of gas.

  For separation or concentration, a separation or concentration method called pervaporation method (pervaporation method) or vapor permeation method (vapor permeation method) can be used. Since the pervaporation method is a separation or concentration method in which a liquid mixture is introduced as it is into a separation membrane, the process including separation or concentration can be simplified.

  In the present invention, when the mixture to be separated or concentrated is a mixture of gases composed of a plurality of components, examples of the mixture of gases include carbon dioxide, oxygen, nitrogen, hydrogen, methane, ethane, ethylene and propane. And at least one selected from aromatic compounds such as propylene, normal butane, isobutane, 1-butene, 2-butene, isobutene and toluene, sulfur hexafluoride, helium, carbon monoxide, nitrogen monoxide, water and the like Those containing ingredients are mentioned. Of the mixture of these gas components, the gas component with high permeability passes through the separation membrane and is separated, and the gas component with low permeability is concentrated on the feed gas side. Therefore, in the above description, the gas to be treated is the carbon dioxide gas-containing gas, but the separation membrane permeable component in the gas to be treated may be other than carbon dioxide gas.

DESCRIPTION OF SYMBOLS 1 separation membrane module 2 housing 3 tubular separation membrane 4 end pipe 5 support plate 5a insertion hole 5c large hole 6A bottom cover 6B top cover 6a extraction port 7, 8 baffle 7a, 8a insertion hole 9 inlet 10 outlet 11, 12 Chamber 13 Main chamber 14 Rod 16 Outflow chamber 20 End plug 29 Water vapor separator 30, 40, 50, 52, 56, 61 Piping 31, 41, 51, 53, 57, 58, 59, 62 Valve 54 Pump 55 Reservoir tank 60 Carbon dioxide gas cylinder 70 heater

Claims (4)

With the housing,
And a separation membrane disposed within the housing;
In a separation membrane module to which a fluid to be treated is supplied and the fluid that has permeated the separation membrane is taken out,
A separation membrane drying means for supplying a drying gas mainly composed of a separation membrane permeable gas into the separation membrane module ,
The separation membrane module, wherein the separation membrane is a zeolite membrane, and the drying gas contains carbon dioxide gas as a main component . The separation membrane module according to claim 1 , wherein the drying gas is a gas generated by concentrating carbon dioxide gas by the membrane separation process of the separation membrane module. A method of operating a separation membrane module according to claim 1 or 2 , wherein
A method of operating a separation membrane module, comprising: drying the separation membrane with the drying gas when the separation membrane module is started. The method for operating a separation membrane module according to claim 3, wherein the gas to be treated supplied to the separation membrane module is subjected to dehydration treatment.

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