JP5442237B2 - Separation membrane module - Google Patents

Description

  The present invention relates to a separation membrane module including a separation membrane that separates a gas containing a specific component into a high concentration gas containing the specific component at a high concentration and a low concentration gas containing the specific component at a low concentration.

  Conventionally, separation membranes that can separate and concentrate a specific component from a gas mixture by utilizing a difference in dissolution diffusion coefficient with respect to a polymer membrane have been applied in various industrial fields. For example, separation of oxygen and nitrogen from air, separation and recovery of hydrogen from off-gas of the platform method, separation and recovery of hydrogen during ammonia synthesis, recovery of carbon dioxide from exhaust gas from thermal power generation and garbage incineration, and nitrogen oxides and sulfur Removal of oxides, separation and recovery of carbon dioxide from off-gas of oil fields, removal of acidic gases such as hydrogen sulfide and carbon dioxide from natural gas mainly composed of methane, separation and recovery of helium, precision machinery and ozone generator This is applied to many fields such as air dehumidification, dehydration from organic solvents, and separation / recovery of evaporated fuel from evaporated fuel-containing gas generated from gasoline fuel. As one of the forms of the separation membrane, there are hollow fiber membranes as described in Patent Documents 1 to 3. These differ in the object of separation, but have a basic structure in which a functional layer made of a non-porous polymer membrane is laminated on the surface of a porous hollow fiber-like support. When this is modularized, a hollow fiber membrane is provided in a hollow case having an air supply port and an exhaust port and having no gas permeability.

  In addition, when a specific component such as isoprene gas and other components are separated and recovered from a mixed gas containing three or more petroleum-derived evaporating components such as naphtha light fraction, the permeability coefficient of the specific component to the membrane is high. Patent Document 4 discloses a gas separation method in which two types of separation membranes, that is, a specific component concentration membrane and a specific component dilution membrane having a low permeation coefficient of a characteristic component with respect to the membrane are provided in series to perform multistage separation.

JP-A-63-315104 JP-A-9-66224 JP 2008-173573 A JP-A-9-66217

  The hollow fiber membranes of Patent Documents 1 to 3 are intended to concentrate and separate by allowing only specific components to pass through, and only one type of functional layer is laminated on the surface of the hollow fiber (support). is there. That is, one hollow fiber membrane has only a separation function for one component. Therefore, in order to separate and recover each component from a mixed gas containing a plurality of components, there is no choice but to prepare a plurality of separation membranes with different separation targets and sequentially permeate them. Also in Patent Document 4, a plurality of specific component separation membrane modules or a combination of a specific component separation membrane module and a specific component separation membrane module are arranged in series via a communication pipe, and a plurality of evaporated fuel-containing gas or mixed gas are sequentially provided. By supplying to the separation membrane module, separation is performed in a plurality of stages.

  However, this increases the size of the device, increases the number of assembling steps and the number of parts of the device, makes it difficult to reduce the weight of the device, increases the number of pipe joint portions, increases the possibility of gas leakage from the joint portions, and increases the cost. Etc. have various problems.

  Therefore, the present invention solves the above-described problem, and provides a separation membrane module that does not increase in size even when a specific component-containing gas is separated and concentrated in multiple stages to recover a specific component Objective.

  The present invention provides a high concentration gas containing a specific component at a high concentration and a low concentration containing a specific component at a low concentration in a hollow case without gas permeability having an air supply port and an exhaust port. A separation membrane module in which a separation membrane that separates into gas is disposed, and a specific component concentration chamber that allows a specific component to have a high concentration by passing through the separation membrane in the hollow case, and the separation membrane A specific component dilution chamber that does not permeate the specific component so that the specific component has a high concentration is provided in series, and the specific component concentration chamber and the specific component dilution chamber are the upstream side (supply port side) of the chamber. Only one of the gas that has permeated through the separation membrane or the gas that has not permeated through the separation membrane is in fluid communication, and the exhaust port is separated and purified in the specific component concentration chamber and the specific component dilution chamber. Gas As it will be evacuated to respectively separate, and being provided by the number corresponding to the type of gas to be separated and purified.

  As a form of the separation membrane module, a partition wall that partitions the specific component concentration chamber and the specific component dilution chamber is provided in a direction intersecting the separation membrane, and the separation membrane includes an inner surface of a porous hollow fiber-like support. Or it is set as the hollow fiber membrane which laminated | stacked the functional layer which consists of a non-porous polymer membrane on the outer surface. In addition, a concentration functional layer that increases the concentration of the specific component by passing through the membrane in the specific component concentration chamber is stacked on one support, and the membrane does not pass through the specific component dilution chamber. A dilution functional layer for increasing the concentration of the specific component is laminated, and the specific component concentration chamber and the specific component dilution chamber can be communicated with each other through a cavity of the hollow fiber membrane.

  According to the separation membrane module of the present invention, the specific component concentration chamber and the specific component dilution chamber are provided in series in one hollow case, and a plurality of separation membranes are integrated into one module. According to this, even when the specific component-containing gas is separated and recovered in a plurality of stages, it is sufficient to use one separation membrane module. In addition, the number of pipe joints is reduced, and the possibility of gas leakage from the joints is also reduced. If the specific component concentrating chamber and the specific component diluting chamber are in fluid communication with only one of the gas that has permeated the separation membrane or the gas that has not permeated in the upstream chamber, the gas after separation will be Even if a plurality of separation membranes are integrated into one module without being mixed, reliable multi-stage separation is possible. If the exhaust ports are provided in a number corresponding to the type of gas to be separated and purified so that the separated and purified gas is exhausted separately, it is ensured that each separated gas is supplied to a desired supply destination. Therefore, the degree of freedom in designing the processing apparatus including the separation membrane module is increased.

  In addition, the separation membrane is a hollow fiber membrane, and a partition wall that partitions the specific component concentration chamber and the specific component dilution chamber is provided in a direction intersecting the separation membrane. Even in the configuration in which the hollow fiber membranes communicate with each other, a plurality of separation membranes having different functions can be reliably integrated as one module without impairing the function of each separation membrane. At this time, if the concentration functional layer and the dilution functional layer are laminated on one support (hollow fiber) depending on the location, for example, compared to the case where the hollow case has an inner / outer double structure, etc. Further downsizing is possible.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings as appropriate. However, the present invention is not limited thereto, and various modifications can be made without departing from the scope of the present invention. The separation membrane module of the present invention separates oxygen and nitrogen from air, separates and recovers hydrogen from off-gas of the platform method, separates and recovers hydrogen during ammonia synthesis, and recovers carbon dioxide from exhaust gas from thermal power generation and garbage incineration. And removal of nitrogen oxides and sulfur oxides, separation and recovery of carbon dioxide from off-gas of oil fields, removal of acidic gases such as hydrogen sulfide and carbon dioxide from natural gas mainly composed of methane, and separation and recovery of helium, precision The present invention can be applied to gas processing devices such as air dehumidification for machines and ozone generators, dehydration from organic solvents, and separation and recovery of evaporated fuel from evaporated fuel-containing gas generated from gasoline fuel. Hereinafter, a case where the present invention is applied to an evaporative fuel processing apparatus that separates and recovers evaporative fuel from an evaporative fuel containing gas will be described as an example.

  Unlike the method in which the evaporated fuel (vapor) adsorbed by the canister is desorbed (purged) using the negative pressure of the intake pipe when the engine is driven, the evaporated fuel processing device is purged by a pump to form a separation membrane. It is configured as a purgeless evaporation system that supplies pressurized fuel and collects the evaporated fuel separated by the separation membrane at a high concentration, and is installed in vehicles that employ an idling stop system, a hybrid system, or a direct injection engine. .

In FIG. 1, the schematic block diagram of the evaporative fuel processing apparatus which has a separation membrane module which concerns on Example 1 of this invention is shown. The evaporative fuel processing apparatus includes a canister 2 that adsorbs and collects evaporative fuel generated from the fuel tank 1, and an evaporative fuel-containing gas that includes the evaporative fuel desorbed from the canister 2, and a high-concentration gas that includes the evaporative fuel in a high concentration. And a separation membrane module that includes a separation membrane that separates the fuel into a low-concentration gas containing a low concentration of vaporized fuel, and a pump 3 that pumps the vaporized fuel-containing gas from the canister 2 to the separation membrane module. In the canister 2, a partition wall 2 a that divides the internal space of the canister 2 into two is integrally formed.

  The fuel tank 1 and the canister 2 are communicated with each other via an evaporation line 10. A pump 3 is disposed on the purge line 11. The canister 2 is also connected to an atmospheric line 16 whose tip communicates with the atmosphere.

  In the canister 2, an adsorbent made of a porous body that contains the vaporized fuel generated in the fuel tank 1 is adsorbed and collected and air that has a molecular diameter smaller than that of the fuel component is permeated without being adsorbed. Activated carbon can be used as the adsorbent. It is also preferable to provide a heater constituted by a heating element device such as a piezo element that heats the inside of the canister 2. The pump 3 is electrically driven and desorbs the evaporated fuel adsorbed in the canister 2 and pumps the evaporated fuel-containing gas containing the desorbed evaporated fuel and air to the separation membrane module side. The pump 3 is controlled by an electronic control unit (ECU) (not shown). The ECU includes a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), and the like. A predetermined control program is stored in advance in the ROM, and the CPU controls the pump 3 and the like at a predetermined timing based on the control program.

  When evaporated fuel is generated from the fuel tank 1, the evaporated fuel is adsorbed and collected in the canister 2 through the evaporation line 10, and excess air components are discharged from the atmospheric line 16 through the canister 2. When an internal combustion engine start switch such as an ignition switch (IG switch) or a starter is turned on, the pump 3 is driven to generate an air flow from the canister 2 to the separation membrane module side. Then, by introducing air (outside air) from the atmospheric line 16, the evaporated fuel adsorbed in the canister 2 is desorbed (purged). The evaporated fuel purged from the canister 2 is pumped and supplied to the separation membrane module through the purge line 11 by the pump 3 as an evaporated fuel-containing gas together with the air component sucked from the atmospheric line 16. Then, the fuel component is preferentially permeated and separated from the evaporated fuel-containing gas, and the concentrated gas containing the evaporated fuel at a high concentration is purified. The concentrated gas is recovered to the fuel tank 1 through the recovery line 12.

Example 1
In FIG. 1, the schematic block diagram of the evaporative fuel processing apparatus which has the separation membrane module 60 which concerns on Example 1 of this invention is shown. The separation membrane module 60 of Example 1 is characterized in that only one hollow case 61 is used, and one hollow fiber membrane 23 has both a concentration function and a dilution function. The fuel vapor containing gas G ₀ from the canister 2, are supplied to the separation membrane module 60 directly present invention.

  As shown in FIG. 1, in the separation membrane module 60, a plurality of hollow fiber membranes 23 are arranged in the vicinity of the left and right ends of the hollow case 61 in a hollow case 61 that does not have gas permeability. . Each hollow fiber membrane 23 is supported in a state of being inserted through partition plates 62 to 65 having no gas permeability. Thereby, the inside of the hollow case 61 is partitioned into a plurality of chambers along the longitudinal direction of the hollow fiber membrane 23 by the partition plates 62 to 65, and each chamber communicates through the cavity of the hollow fiber membrane 23. Become. The partition plates 62 to 65 correspond to the partition walls of the present invention, and the partition walls 62 to 65 are provided so as to intersect with the respective hollow fiber membranes 23. Each hollow fiber membrane 23 has a concentrated functional layer 23b that increases the concentration of evaporated fuel by permeating the membrane with respect to one hollow fiber-like porous support 23a, and evaporating fuel by increasing the concentration of evaporated fuel by not permeating the membrane. Dilution function layers 23c for concentration are laminated on the outer surface of the support 23a in a state of being divided in the longitudinal direction with the partition plate 64 interposed therebetween. Thereby, the space between the partition plate 62 and the partition plate 63 from the upstream side (the air supply port 70 side) becomes the primary concentration chamber 66, and the space between the partition plate 63 and the partition plate 64 becomes the secondary concentration chamber 67. A dilution chamber 68 is formed between 64 and the partition plate 65.

  The air supply port 70 is provided on one end wall of the hollow case 61 so as to face the start end of each hollow fiber membrane 23. The first exhaust port 71 is provided on the peripheral wall of the hollow case 61 that is desired for the first concentration chamber 66. The purge line 11 is connected to the air supply port of the separation membrane module 60, and the recovery line 12 is connected to the first exhaust port 71. The second exhaust port 72 is provided on the peripheral wall of the hollow case 61 desired in the second concentration chamber 67, and the first circulation line 14 is connected to the second exhaust port 72. The third exhaust port 73 is provided on the peripheral wall of the hollow case 61 desired for the dilution chamber 68, and the second circulation line 14 is connected to the third exhaust port 73. The fourth exhaust port 74 is provided on the other end wall of the hollow case 61 so as to face the end of each hollow fiber membrane 23, and the return line 15 is connected to the fourth exhaust port 74. .

Next, the operation of the evaporated fuel processing apparatus will be described. The supplied evaporated fuel-containing gas G ₀ including the evaporated fuel desorbed from the canister 2 by the pump 3 is directly supplied to the separation membrane module 60. The separation membrane module 60 of Example 1 is an internal pressure separation system, and the evaporated fuel-containing gas G ₀ supplied from the supply port 70 flows into the cavities of the hollow fiber membranes 23. Then, in the first concentrating compartment 66 in the most upstream in the interior of the separation membrane module 60, the fuel vapor containing gas G ₀ in the fuel component P ₁ is preferentially transmitted separated from the concentrated functional layer 23b of the hollow fiber membranes 23 Then, the primary concentrated gas having a higher evaporated fuel concentration than the supplied evaporated fuel-containing gas G ₀ is purified in the first concentration chamber 66. The primary concentrated gas is recovered from the first exhaust port 71 into the fuel tank 1 through the recovery line 12. On the other hand, inside the hollow of the hollow fiber membrane 23, medium concentration gas G in which air that has not been separated by the enrichment functional layer 23b of the hollow fiber membrane 23 and evaporative fuel that remains without being separated by the enrichment functional layer 23b coexists. ₁ remains and flows as it is through the hollow of the hollow fiber membrane 23 toward the second concentration chamber 67. Then, similarly to the first concentration chamber 66, also in the second concentration chamber 67, the fuel component P ₁ is preferentially permeated and separated from the medium concentration gas G ₁ by the concentration functional layer 23b of the hollow fiber membrane 23, secondary enrichment gas fuel vapor concentration than the gas G ₁ into which is fed to the second concentrating chamber 67 elevated is purified. The secondary concentrated gas is returned to the upstream of the pump 3 through the circulation line 14 from the second exhaust port 72. On the other hand, in the hollow of the hollow fiber membrane 23, a low concentration in which air that has not been separated by the concentration functional layer 23b of the hollow fiber membrane 23 and a small amount of evaporated fuel that remains without being separated by the concentration functional layer 23b coexists. gas G ₃ remains and continue to flow into the dilution chamber 68 direction as it passes through the cavity of the hollow fiber membrane 23. Then, in the dilution chamber 68, the air component P ₂ is preferentially permeated and separated from the low-concentration gas G ₃ by the dilution functional layer 23 c of the hollow fiber membrane 23, and the low-concentration gas G supplied to the dilution chamber 68 is supplied. _The diluted gas whose vaporized fuel concentration is further lowered than ₃ (the air concentration is increased) is purified. The dilution gas is returned from the third exhaust port 73 to the canister 2 through the return line 15. On the other hand, the hollow interior of the hollow fiber membrane 23, tertiary concentrated gas G ₄ is left containing the evaporated fuel that has not been separated in the diluted functional layer 23c of the hollow fiber membrane 23, exits as it is to the other end of the hollow fiber membranes 23 The refrigerant is refluxed from the fourth exhaust port 74 through the second circulation line 14 and upstream of the pump 3. The separation efficiency (specific component concentration in the permeated gas) by the gas separation membrane tends to increase as the specific component concentration in the supplied gas increases. Therefore, in the first embodiment, the evaporated fuel concentration of the primary concentrated gas separated and purified in the first concentration chamber 66 is higher than the evaporated fuel concentration of the secondary concentrated gas separated and purified in the second concentration chamber 67. .

(Other variations)

Oite to Example 1, by changing the number of the partition plate that corresponds to the partition wall of the present invention can be designed to count concentrated (the number of multiple separation). In this case, in addition to dividing the concentration functional layer and the dilution functional layer into two, a dilution functional layer is provided between the concentration functional layers, or a plurality of concentration functional layers and dilution functional layers are alternately divided. It may be provided. The hollow case is not limited to a cylindrical shape.

  Also in each of these modified examples, the exhaust ports are provided at appropriate positions corresponding to the types of gases to be separated and purified so that the gases separated and purified in the concentration chamber and the dilution chamber are separately exhausted. . At this time, a circulation line or a return line may be appropriately connected to each exhaust port according to the type of gas to be separated. In addition, the medium concentration gas separated by the first separation membrane may be supplied.

  The separation membrane module of the present invention can be used not only when the evaporated fuel is separated and recovered from the evaporated fuel-containing gas, but also when the characteristic components are separated and recovered from the various mixed gases described above. In this case, it is only necessary to change the material of the functional layer to a material having a high transmission coefficient for a specific component as appropriate, such as the functional layer material described in Patent Documents 1 to 3.

In actual Example 1, the pump 3 is provided on the purge line 11 upstream of the separation membrane module, but by pressure supplied to the fuel vapor containing gas to the separation membrane from Staphylococcus 2 to calibration, among others, for example, By providing the pump 3 on the return line 15 or the like, the vaporized fuel-containing gas can be supplied from the canister 2 to the separation membrane under reduced pressure by the pump 3 provided downstream from each separation membrane module.

  The evaporative fuel processing device is operated by driving the pump when an internal combustion engine starting switch such as an IG switch or a starter is turned on. However, the evaporative fuel processing device may be operated while the internal combustion engine is stopped.

1 is a schematic configuration diagram of a fuel vapor processing apparatus according to Embodiment 1. FIG.

1 Fuel tank 2 Canister 3 Pump 10 Evaporation line 11 Purge line 12 Recovery line 13/14 Circulation line 15 Return line
2 3 Hollow fiber membrane 23 b Concentrated functional layer 23 c Diluted functional layer
6 0 separation membrane module 6 1 hollow casing 62-6 5 partition plate 6 6 concentration chamber 6 7 concentrating chamber 7 0 supply port 71-7 fourth exhaust port _{G 0} evaporative fuel-containing gas _{G 1} concentration gas
G ₃ low concentration gas _{G 4} tertiary concentrated gas
P ₁ Fuel component P ₂ Air component

Claims (1)

The gas containing a specific component is separated into a high-concentration gas containing a specific component at a high concentration and a low-concentration gas containing a specific component at a low concentration in a non-gas permeable hollow case having an air supply port and an exhaust port. A separation membrane module in which a separation membrane is disposed,
In the hollow case, a specific component concentration chamber that increases the concentration of the specific component by passing through the separation membrane and a specific component dilution chamber that increases the concentration of the specific component by not passing through the separation membrane are connected in series. It is provided in
The specific component concentration chamber and the specific component dilution chamber are in fluid communication with only one of the gas that has permeated the separation membrane or the gas that has not permeated the separation membrane in the upstream chamber. ,
The exhaust ports are provided in a number corresponding to the types of gases to be separated and purified so that the gases separated and purified in the specific component concentration chamber and the specific component dilution chamber are separately exhausted.
A partition wall that partitions the specific component concentration chamber and the specific component dilution chamber is provided in a direction intersecting the separation membrane,
The separation membrane is a hollow fiber membrane in which a functional layer made of a non-porous polymer membrane is laminated on the inner surface or outer surface of a porous hollow fiber support.
Concentrated functional layers that make the specific component highly concentrated by permeating the membrane in the specific component concentration chamber are stacked on one support, and the specific component is not transmitted through the membrane in the specific component dilution chamber. Is layered with a dilution function layer that increases the concentration of
The separation membrane module, wherein the specific component concentration chamber and the specific component dilution chamber communicate with each other through a cavity of the hollow fiber membrane.

Images