JP2016068082A - Separation performance evaluation method of zeolite membrane and production method of zeolite membrane structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a simple separation performance evaluation method of a zeolite membrane and a production method of a zeolite membrane structure having a step of evaluating the separation performance of the zeolite membrane by the method.SOLUTION: A separation performance evaluation method of a zeolite membrane comprises: a step forecasting a first forecast permeation flux where a permeable component contained in a liquid mixture being the separation object of the zeolite membrane permeates the zeolite membrane based on a first measured permeation rate at which a first gas component permeates the zeolite membrane when the first gas component is supplied to the zeolite membrane; and a step forecasting a second forecast permeation flux where a residual component contained in a liquid mixture permeates the zeolite membrane based on a second measured permeation rate at which a second gas component permeates the zeolite membrane when the second gas component is supplied to the zeolite membrane.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for evaluating the separation performance of a zeolite membrane, and a method for producing a zeolite membrane structure comprising a step of evaluating the separation performance of a zeolite membrane by the method.

  Conventionally, the separation performance of a zeolite membrane has been evaluated by selectively allowing a specific component to permeate from a multicomponent liquid mixture actually used.

  For example, in Patent Document 1, the separation coefficient of an LTA type zeolite membrane is evaluated by separating a liquid mixture of water and ethanol with an LTA type zeolite membrane using a pervaporation method and a vapor permeation method. In Patent Document 2, the separation factor of a CHA-type zeolite membrane is evaluated by separating a liquid mixture of water and acetic acid with a CHA-type zeolite membrane using a pervaporation method. In Patent Document 3, the permeability of a MOR type zeolite membrane is evaluated by separating a liquid mixture of water and acetic acid with a MOR type zeolite membrane using a vapor permeation method. In Patent Document 4, the separation factor of a DDR type zeolite membrane is evaluated by separating a liquid mixture of water and ethanol with a DDR type zeolite membrane using a pervaporation method.

JP 2003-210950 A JP 2012-67090 A JP2013-188687A Japanese Patent No. 5346580

  However, when evaluating the separation performance using the pervaporation method as a performance inspection before shipment, a step of controlling the temperature of the liquid mixture and a step of drying the liquid mixture adhering to the evaluated zeolite membrane are required. is there.

  Also, when evaluating the separation performance using the vapor permeation method, the step of vaporizing the liquid mixture, the step of heating the vaporized mixture or the zeolite membrane itself, and the zeolite whose temperature decreases according to the reduced pressure after permeation A step of drying the liquid mixture that aggregates on the surface of the membrane is necessary.

  The present invention has been made in view of the above situation, and provides a simple method for evaluating the separation performance of a zeolite membrane and a method for producing a zeolite membrane structure comprising a step of evaluating the separation performance of a zeolite membrane by the method. The purpose is to do.

  The method for evaluating the separation performance of a zeolite membrane according to the present invention is based on the first measured permeation rate at which the first gas component permeates the zeolite membrane when the first gas component is supplied to the zeolite membrane. A step of predicting a first predicted permeation flux in which a permeation component contained in a liquid mixture permeates the zeolite membrane; and a second step of allowing the second gas component to permeate the zeolite membrane when the second gas component is supplied to the zeolite membrane. Predicting a second predicted permeation flux through which residual components contained in the liquid mixture permeate the zeolite membrane based on the actually measured permeation speed. When the molecular diameter of the permeation component is 0.93 times or less of the pore diameter of the zeolite membrane, the molecular diameter of the first gas component is 0.93 times or less of the pore diameter, and the molecular diameter of the permeation component is 0.93 of the pore diameter. When it is larger than twice and smaller than 1.07 times, the molecular diameter of the first gas component is made larger than 0.93 times and smaller than 1.07 times the pore diameter. When the molecular diameter of the residual component is 1.07 times or more of the pore diameter of the zeolite membrane, the molecular diameter of the second gas component is 1.07 times or more of the pore diameter, and the molecular diameter of the residual component is 0.93 of the pore diameter. When it is larger than twice and smaller than 1.07 times, the molecular diameter of the second gas component is made larger than 0.93 times and smaller than 1.07 times the pore diameter.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of a zeolite membrane structure provided with the process of evaluating the isolation | separation performance of a zeolite membrane simple and the separation performance of a zeolite membrane by the said method can be provided.

Sample No. Graph showing the correlation between the measured flux of the measured transmission rate and water CO ₂ according to the 1-46 Sample No. Graph showing the correlation between the measured permeation rate of CF ₄ and the measured permeation flux of acetic acid according to 1 to 46 Sample No. Graph showing the correlation between the measured flux of the measured transmission rate and water CO ₂ according to the 3 to 13 Sample No. Graph showing the correlation between the measured flux of the measured transmission speed and ethanol CF ₄ according to the 3 to 13 Sample No. Graph showing the correlation between the measured flux of the measured transmission rate of ethanol CH ₄ according to the 5-16

  Next, embodiments of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, the drawings are schematic, and the ratio of each dimension may be different from the actual one. Accordingly, specific dimensions and the like should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

(Configuration of zeolite membrane structure)
The zeolite membrane structure includes a porous support and a zeolite membrane.

  The porous support has chemical stability such that a zeolite membrane can be crystallized (deposited) into a film on the surface. As a material constituting the porous support, for example, a ceramic sintered body, a metal, an organic polymer, glass, carbon, and the like can be used. Examples of the ceramic sintered body include alumina, silica, mullite, zirconia, titania, yttria, silicon nitride, silicon carbide, and the like. Examples of the metal include aluminum, iron, bronze, silver, and stainless steel. Examples of the organic polymer include polyethylene, polypropylene, polytetrafluoroethylene, polysulfone, and polyimide.

  The porous support may have any shape that can supply the liquid mixture to be separated to the zeolite membrane. Examples of the shape of the porous support include a honeycomb shape, a monolith shape, a flat plate shape, a tubular shape, a cylindrical shape, a columnar shape, and a prismatic shape. When the porous support is cylindrical, the length in the longitudinal direction can be 150 to 2000 mm, and the diameter in the radial direction can be 30 to 220 mm, but is not limited thereto.

  The porous support has a plurality of open pores. The average pore diameter of the porous support may be a size that allows a permeation component that permeates the zeolite membrane in the liquid mixture to be separated. Increasing the average pore diameter tends to increase the permeation amount of the permeation component. Decreasing the average pore diameter increases the strength of the porous support itself and flattens the surface of the porous support. It becomes easy to form a simple zeolite membrane. For example, the porosity of the porous support can be 25% to 50%, and the average pore diameter of the porous support can be 0.05 μm to 25 μm, but is not limited thereto.

  The porous support may be constituted by a single layer having a uniform average pore diameter, or may be constituted by a plurality of layers having different average pore diameters. When the porous support is composed of a plurality of layers, each layer may be composed of a different material among the above materials, or may be composed of the same material.

  The zeolite membrane is formed on the surface of the porous support. When the porous support is formed in a honeycomb or monolith shape, the zeolite membrane is formed on the inner surface of each of the plurality of through holes formed in the porous support.

  The crystal structure (type) of the zeolite membrane is not particularly limited. For example, LTA, CHA, DDR, MOR, DOH, MFI, FAU, OFF / ERI, LTL, FER, BEA, BEC, CON, MSE, MEL , MTW, MEI, MWW, RHO, BOG, SZR, EMT, SOD, AEI, AEL, AEN, AET, AFN, AFO, AFR, AFS, AFT, AFI, AFX, ANA, CAN, GIS, GME, HEU, JBW , KFI, LAU, LEV, MAZ, MER, MFS, MTT, PHI, SFG, TUN, TON, UFI, VET, VFI, VNI, and VSV. In consideration of the use of gaseous components at normal temperature and pressure in the evaluation method according to the present invention, an oxygen 8-membered ring zeolite membrane or an oxygen 6-membered ring zeolite membrane is preferred, and in particular, DDR type, LTA type, CHA type. , LEV type, SOD type and DOH type are preferable.

  The zeolite membrane is composed of a large number of zeolite crystals, and has a large number of pores in the zeolite crystals. The pore diameter is mainly determined by the crystal structure of the zeolite. The pore diameter of the main zeolite is about 0.3 nm to 0.8 nm. The pore diameter may have a major axis and a minor axis. For example, the minor axis of the pores of DDR type zeolite is 0.36 nm and the major axis is 0.44 nm. The MFI-type zeolite has two kinds of pores: a pore having a minor axis of 0.51 nm and a major axis of 0.55 nm, and a pore having a minor axis of 0.53 nm and a major axis of 0.56 nm.

  In addition to the plurality of pores, defects may exist in the zeolite membrane. The defect may penetrate the zeolite membrane in the thickness direction. In this case, the inner diameter of the defect may be larger than the zeolite pore diameter.

  The liquid mixture that is the separation target of the zeolite membrane contains a permeation component and a residual component. The permeating component is a component that easily permeates the zeolite membrane and is easily separated from the liquid mixture. In general, the molecular diameter of the permeable component is equal to or smaller than the pore diameter. A residual component is a component which is hard to permeate | transmit a zeolite membrane and tends to remain in a liquid mixture. In general, the molecular diameter of the residual component is larger than the pore diameter. In addition, when the pore diameter has a major axis and a minor axis, the average value of the major axis and the minor axis may be defined as the pore diameter (Ch. Baerlocher, LB McCusker and DH Olson, Atlas of Zeolite Framework Types, 6th ed. 2007)). Therefore, the DDR type zeolite has one kind of pore size of 0.40 nm. There are two types of pore sizes of MFI-type zeolite, 0.53 nm and 0.545 nm.

  A liquid mixture of water and organic matter can be used as the liquid mixture to be separated from the zeolite membrane. Examples of organic substances include acids such as acetic acid, alcohols such as methanol, ethanol and propanol, ketones such as acetone and methyl ethyl ketone, and halogenated hydrocarbons such as carbon tetrachloride and trichloroethylene. For example, a DDR type zeolite membrane is suitable as a separation membrane for separating water from a water-ethanol liquid mixture or a water-acetic acid liquid mixture.

  Here, a method for separating a liquid mixture using a zeolite membrane will be described. The first surface of the zeolite membrane is brought into contact with the liquid mixture or vapor vaporized from the liquid mixture, and the second surface (surface opposite to the first surface) side of the zeolite membrane is set to a pressure lower than that of the first surface side. This selectively permeates the permeate component from the liquid mixture. Thereby, a residual component is collect | recovered or concentrated by isolate | separating a permeation | transmission component (for example, water) from a liquid mixture and raising the density | concentration of a residual component (for example, organic substance). Such a separation method is widely known as a pervaporation method or a vapor permeation method.

(Method for evaluating separation performance of zeolite membrane)
Since zeolite membranes are used to separate permeate components from liquid mixtures, conventionally, the separation performance of zeolite membranes has been evaluated using actual liquid mixtures. However, such conventional evaluation methods require complicated steps such as temperature control of the liquid mixture and drying of the zeolite membrane. Therefore, in this embodiment, as described below, since the gas single component or gas mixture is used instead of the actual liquid mixture, the separation performance can be easily evaluated (predicted) compared to the case where the liquid mixture is used. Can do. In the following, the case where the separation performance is evaluated using a single gas component will be described.

  First, the 1st gas component corresponding to the permeation | transmission component contained in the liquid mixture which is the separation object of a zeolite membrane is prepared.

  At this time, when the zeolite membrane has only one kind of pore diameter, the molecular diameter of the first gas component is set as follows. When the molecular diameter of the permeation component is 0.93 times or less of the pore diameter of the zeolite membrane, the molecular diameter of the first gas component is 0.93 times or less of the pore diameter, and the molecular diameter of the permeation component is less than the pore diameter. When the ratio is greater than 0.93 and less than 1.07, the molecular diameter of the first gas component is greater than 0.93 and less than 1.07 times the pore diameter.

On the other hand, when the zeolite membrane has two or more kinds of pore diameters, it is necessary to set the molecular diameter of the first gas component by paying attention to the pore diameter that can be determined to be effective for permeation of the permeation component. Specifically, when the first pore diameter of the zeolite membrane is x, the second pore diameter of the zeolite membrane is y (> x), and the molecular diameter of the permeation component is p, the following (A) to (C) One condition that p satisfies is selected, and one condition that p satisfies (a) to (c) is selected. Then, the molecular diameter of the first gas component is set within a range that satisfies both the condition selected from (A) to (C) and the condition selected from (a) to (c).
(A) x × 0.93 or less (B) Greater than x × 0.93 and less than x × 1.07 (C) x × 1.07 or more (a) y × 0.93 or less (b) Greater than y × 0.93 and less than y × 1.07 (c) y × 1.07 or more

  Next, a zeolite membrane structure is prepared, and moisture adsorbed on the zeolite membrane is removed by heating the zeolite membrane at 200 ° C. or higher. In this case, heating at 300 ° C. or higher is preferable, and heating at 350 ° C. or higher is more preferable. Moreover, it is preferable to heat a zeolite membrane for 1 hour or more, and 5 hours or more are more preferable. In addition, when the zeolite membrane structure is temporarily stored after the heating, when the humidity exceeds 30% and exceeds one week, or when the humidity exceeds 30% and exceeds 48 hours, the heating treatment is preferably performed again.

  Next, the first gas component is brought into contact with the first surface of the zeolite membrane, and the first gas component released from the second surface is recovered by setting the second surface side of the zeolite membrane to a pressure lower than that of the first surface side. To do.

  Next, a second gas component corresponding to a residual component (a component that is less permeable to the zeolite membrane than the permeation component) contained in the liquid mixture that is the separation target of the zeolite membrane is prepared.

  At this time, when the pore diameter of the zeolite membrane is only one kind, the molecular diameter of the second gas component is set as follows. When the molecular diameter of the residual component is 1.07 times or more of the pore diameter, the molecular diameter of the second gas component is 1.07 times or more of the pore diameter, and the molecular diameter of the residual component is 0.93 times the pore diameter. When it is large and less than 1.07 times, the molecular diameter of the second gas component is made larger than 0.93 times and smaller than 1.07 times the pore diameter.

On the other hand, when the zeolite membrane has two or more kinds of pore diameters, it is necessary to set the molecular diameter of the second gas component by paying attention to the pore diameter that can be judged to be effective for non-permeation of residual components. Specifically, when the first pore diameter of the zeolite membrane is x, the second pore diameter of the zeolite membrane is y (> x), and the molecular diameter of the residual component is q (> p), the following (D) One condition that q satisfies in (F) is selected, and one condition that q satisfies in (d) to (f) is selected. Then, the molecular diameter of the second gas component is set within a range that satisfies both the condition selected from (D) to (F) and the condition selected from (d) to (f).
(D) x × 0.93 or less (E) Greater than x × 0.93 and less than x × 1.07 (F) x × 1.07 or more (d) y × 0.93 or less (e) Greater than y × 0.93 and less than y × 1.07 (f) y × 1.07 or more

  In general, since the molecular diameter q of the residual component is larger than the molecular diameter p of the permeating component, the molecular diameter of the second gas component is preferably larger than the molecular diameter of the first gas component. Moreover, it is preferable that the molecular diameter of a 2nd gas component is 1.5 times or less of the pore diameter formed in the zeolite membrane. As a result, the residual components that pass through the defects in the zeolite membrane can be reproduced more accurately.

  Next, the second gas component is brought into contact with the first surface of the zeolite membrane, and the second gas component released from the second surface is recovered by setting the second surface side of the zeolite membrane to a pressure lower than that of the first surface side. To do.

  Next, the first measured transmission speed of the first gas component is measured based on the recovered amount of the first gas component recovered, and the second gas component of the second gas component is measured based on the recovered amount of the second gas component recovered The second actually measured transmission speed is measured. The permeation rate is a value obtained by dividing the permeation amount per unit time by the zeolite membrane area and further dividing by the differential pressure between the first surface side and the second surface side.

  Next, based on the first measured permeation rate, a first predicted permeation flux in which the permeation component of the liquid mixture permeates the zeolite membrane is predicted. Similarly, based on the second actually measured permeation speed, a second predicted permeation flux at which the residual component of the liquid mixture permeates the zeolite membrane is predicted. At this time, a correspondence table between each measured permeation speed and each predicted permeation flux may be used, or a calculation formula for deriving each predicted permeation flow rate from each actual permeation speed may be used. The permeation flux is a value obtained by dividing the permeation amount per unit time by the zeolite membrane area.

  As described above, the separation performance of the zeolite membrane can be evaluated by acquiring the first predicted permeation flux of the permeation component and the second predicted permeation flux of the residual component.

(Method for producing zeolite membrane structure)
A method for producing a zeolite membrane structure will be described.

  First, the raw material of the porous support is formed into a desired shape using an extrusion molding method, a press molding method, a cast molding method, or the like.

  Next, the molded body of the porous support is fired (for example, 900 ° C. to 1450 ° C.) to form the porous support.

  Next, a zeolite membrane is formed on the surface of the porous support. As a method for forming the zeolite membrane, a known method such as a hydrothermal synthesis method can be used according to the crystal structure of the zeolite membrane.

  Next, according to the method for evaluating the separation performance of the zeolite membrane, the first predicted permeation flux of the permeation component is predicted from the first actual permeation rate of the first gas component, and the residual from the second actual permeation rate of the second gas component. Predict the second predicted permeation flux of the component. Then, the separation performance of the zeolite membrane for the liquid mixture is evaluated from the first predicted permeation flux and the second predicted permeation flux.

(Other embodiments)
As mentioned above, although one Embodiment of this invention was described, this invention is not limited to the said embodiment, A various change is possible in the range which does not deviate from the summary of invention.

  (A) In the above embodiment, by supplying the single gas component of each of the first gas component and the second gas component to the zeolite membrane, the first actually measured transmission speed of the first gas component and the second actually measured second gas component. The first measured transmission speed and the second measured transmission speed are obtained by supplying a mixed gas containing one or both of the first gas component and the second gas component to the zeolite membrane. May be obtained. That is, the first actually measured transmission rate may be acquired by supplying the first gas component to the zeolite membrane, and the second actually measured transmission rate may be acquired by supplying the second gas component to the zeolite membrane. The step of acquiring the first actually measured transmission speed may be before or after the step of acquiring the second actually measured transmission speed.

  In addition, when acquiring a 1st measured transmission rate previously, it is preferable to heat a zeolite membrane at 200 degreeC or more before supplying a 1st gas component, and a 2nd measured transmission rate is acquired previously. In some cases, it is preferable to heat the zeolite membrane at 200 ° C. or higher before supplying the second gas component.

  (B) In the embodiment described above, the zeolite membrane structure is completed by evaluating the separation performance of the zeolite membrane. However, the evaluation of the separation performance of the zeolite membrane may be performed only once for each lot.

  Examples of the method for evaluating the separation performance of a zeolite membrane according to the present invention will be described below. However, the present invention is not limited to the examples described below.

(Sample preparation)
Sample no. 1-No. A monolithic zeolite membrane structure according to No. 46 was produced.

  First, 20 parts by mass of an inorganic binder was added to 100 parts by mass of alumina particles having an average particle size of 30 μm, and a porous material was prepared by adding water, a dispersant and a thickener and kneading them.

  Next, a monolith type porous body was formed by extruding the adjusted porous material.

  Next, the monolith type porous body was fired (1250 ° C., 1 hour) to produce a monolith type porous body.

  Next, titania, water, and a binder were added to alumina to prepare an intermediate layer slurry, and an intermediate layer formed body was formed on the inner surface of the through hole of the monolith type porous body by a filtration method. Subsequently, the intermediate layer formed body was fired (1250 ° C., 1 hour) to form an intermediate layer.

  Next, a binder and water were added to alumina to prepare a surface layer slurry, and a surface layer molded body was formed on the inner surface of the intermediate layer by a filtration method. Subsequently, the surface layer compact was fired (1250 ° C., 12 hours) to form a surface layer. The monolith type porous support body was completed by the above.

  Next, glass seals were provided on both end faces of the monolith type porous support so as not to block the openings of the through holes.

Next, a DDR type zeolite membrane was formed on the inner surface of the surface layer by the method described in JP 2010-158665 A or International Publication No. 2011/040205. At this time, the permeation flux of the zeolite membrane was varied from sample to sample by adjusting the amount of seed crystals attached and the temperature and time during hydrothermal synthesis.
As a result, a monolithic zeolite membrane structure was completed.

(Measured transmission rate of CO ₂ single component gas and CF ₄ single component gas)
Next, sample no. 1-No. After 46 zeolite membrane structures were heated to 200 ° C. or higher and then cooled to room temperature, the zeolite membrane structures were stored in a SUS container for a gas permeation test.

Next, a CO ₂ (molecular diameter: 0.33 nm) single component gas is allowed to flow inside the through-hole of the zeolite membrane structure at a pressure of 0.2 MPa (absolute pressure), thereby allowing CO ₂ to flow through the first surface of the zeolite membrane. The CO ₂ released from the outer peripheral surface of the monolithic porous support was recovered. The molecular diameter of CO ₂ of 0.33 nm is 0.825 times the pore diameter of 0.40 nm of DDR type zeolite.

Next, the permeation rate of CO ₂ was calculated by dividing the permeation amount of CO ₂ per unit time by the zeolite membrane area and further dividing by the differential pressure.

Similarly, sample no. 1-No. For 46, the transmission rate of CF ₄ was calculated using a single component gas of CF ₄ (molecular diameter: 0.47 nm). Note that the molecular diameter of CF ₄ is 0.47 nm, which is 1.175 times the pore diameter of DDR type zeolite of 0.40 nm.

The zeolite membrane area was 0.035 m ² and the differential pressure was 0.1 MPa.

(Measured permeation flux of water and acetic acid)
Next, each zeolite membrane structure was mounted in a SUS cylindrical container and heated to 90 ° C. with a 90% aqueous acetic acid solution (water molecular diameter: 0.265 nm, acetic acid molecular diameter: 0.43 nm). While circulating in the cell, the outer peripheral surface of the monolithic porous support is decompressed with a vacuum pump to collect the permeated vapor released from the outer peripheral surface of the monolithic porous support, and the composition is subjected to neutralization titration. Analysis by the method.

  The molecular diameter of water, which is a permeation component, of 0.265 nm is 0.66 times the pore diameter of 0.40 nm of DDR type zeolite. The molecular diameter of the residual component, acetic acid, of 0.43 nm is 1.075 times the pore diameter of 0.40 nm of the DDR type zeolite.

  Next, the permeation flux of water was calculated by dividing the permeation amount of water per unit time by the zeolite membrane area. Similarly, the permeate flux of acetic acid was also calculated.

(Prediction accuracy of permeation flux of water and acetic acid)
FIG. 1-No. The correspondence relationship between the measured permeation speed of 46 CO ₂ and the measured permeation flux of water is shown. As shown in FIG. 1, the measured permeation rate of CO ₂ and the measured permeation flux of water are in a proportional relationship. Therefore, it was confirmed that the permeation flux of water can be accurately predicted based on the measured permeation rate of CO ₂ .

FIG. 1-No. 46 shows the correspondence between the measured permeation rate of 46 CF ₄ and the measured permeation flux of acetic acid. As shown in FIG. 2, the measured permeation rate of CF ₄ and the measured permeation flux of acetic acid are in a proportional relationship. Therefore, it was confirmed that the permeation flux of acetic acid can be accurately predicted based on the measured permeation rate of CF ₄ .

From the above, it was confirmed that the permeation flux of the zeolite membrane when separating water from the acetic acid aqueous solution can be accurately predicted based on the measured permeation rates of CO ₂ and CF ₄ .

(Measured transmission rate of CO ₂ single component gas and CF ₄ single component gas)
Next, sample no. 3-No. After 13 zeolite membrane structures were heated at 200 ° C. or higher, the zeolite membrane structures were stored in a SUS container for gas permeation tests.

Next, CO ₂ is brought into contact with the first surface of the zeolite membrane by circulating a CO ₂ single component gas at a pressure of 0.2 MPa (absolute pressure) inside the through-holes of the zeolite membrane structure, so that the monolithic porous CO ₂ released from the outer peripheral surface of the support was recovered. The molecular diameter of CO ₂ of 0.33 nm is 0.825 times the pore diameter of 0.40 nm of DDR type zeolite.

Next, the permeation rate of CO ₂ was calculated by dividing the permeation amount of CO ₂ per unit time by the zeolite membrane area and further dividing by the differential pressure.

Similarly, sample no. 3-No. For 13, the transmission rate of CF ₄ was calculated using a CF ₄ single component gas. Note that the molecular diameter of CF ₄ is 0.47 nm, which is 1.175 times the pore diameter of DDR type zeolite of 0.40 nm.

The zeolite membrane area was 0.035 m ² and the differential pressure was 0.1 MPa.

(Measured permeation flux of water and ethanol)
Next, sample no. 3-No. 13 Zeolite membrane structure was placed in a cylindrical container made of SUS, and 50% ethanol aqueous solution (water molecular diameter: 0.265 nm, ethanol molecular diameter: 0.43 nm) heated to 50 ° C. While circulating inside, the outer peripheral surface of the monolithic porous support is decompressed with a vacuum pump to collect the permeated vapor released from the outer peripheral surface of the monolithic porous support, and the composition is analyzed with a density meter did.

  The molecular diameter of water, which is a permeation component, of 0.265 nm is 0.66 times the pore diameter of 0.40 nm of DDR type zeolite. The molecular diameter of ethanol, which is a residual component, is 0.43 nm, which is 1.075 times the pore diameter of DDR type zeolite of 0.40 nm.

  Next, the permeation flux of water was calculated by dividing the permeation amount of water per unit time by the zeolite membrane area. Similarly, the permeation flux of ethanol was also calculated.

(Prediction accuracy of water and ethanol permeation flux)
FIG. 3-No. 13 shows the correspondence between the measured permeation rate of 13 CO ₂ and the measured permeation flux of water. As shown in FIG. 3, the measured permeation rate of CO ₂ and the measured permeation flux of water are in a proportional relationship. Therefore, it was confirmed that the permeation flux of water can be accurately predicted based on the measured permeation rate of CO ₂ .

FIG. 3-No. 13 shows the correspondence between the measured permeation rate of 13 CF ₄ and the measured permeation flux of ethanol. As shown in FIG. 4, the measured permeation rate of CF ₄ and the measured permeation flux of ethanol are in a proportional relationship. Therefore, it was confirmed that the permeation flux of ethanol can be accurately predicted based on the measured permeation rate of CF ₄ .

From the above, it was confirmed that the permeation flux of the zeolite membrane at the time of separating water from the ethanol aqueous solution can be accurately predicted based on the measured permeation rates of CO ₂ and CF ₄ .

(Measured transmission speed of CH ₄ single component gas)
Next, sample no. 5-No. After the 16 zeolite membrane structures were heated at 200 ° C. or higher, the zeolite membrane structures were stored in a SUS container for gas permeation tests.

Next, CH ₄ (molecular diameter: 0.38 nm) single component gas is allowed to flow inside the through-hole of the zeolite membrane structure at a pressure of 0.2 MPa (absolute pressure), whereby CH ₄ is supplied to the first surface of the zeolite membrane. The CH ₄ released from the outer peripheral surface of the monolith type porous support was recovered. Note that the CH ₄ molecular diameter of 0.38 nm is 0.95 times the pore diameter of 0.40 nm of the DDR type zeolite.

Next, the permeation rate of CH ₄ was calculated by dividing the permeation amount of CH ₄ per unit time by the zeolite membrane area and further dividing by the differential pressure.

The zeolite membrane area was 0.035 m ² and the differential pressure was 0.1 MPa.

(Measured permeation flux of ethanol)
Next, sample no. 5-No. 16 zeolite membrane structures were mounted in a SUS cylindrical container, and a 50% ethanol aqueous solution (ethanol molecular diameter: 0.43 nm) heated to 50 ° C. was circulated in the cell while monolithic porous. The outer peripheral surface side of the porous support was depressurized with a vacuum pump, the permeated vapor released from the outer peripheral surface of the monolith type porous support was recovered, and the composition was analyzed with a density meter.

  Next, the ethanol permeation flux was calculated by dividing the ethanol permeation amount per unit time by the zeolite membrane area. The molecular diameter of ethanol, which is a residual component, is 0.43 nm, which is 1.075 times the pore diameter of DDR type zeolite of 0.40 nm.

(Prediction accuracy of ethanol permeation flux)
FIG. 5-No. 16 shows the correspondence between the measured permeation rate of 16 CH ₄ and the measured permeation flux of ethanol. As shown in FIG. 5, the measured permeation rate of CH ₄ and the measured permeation flux of ethanol were not proportional. That is, it is difficult to accurately predict the ethanol permeation flux based on the measured permeation rate of CH ₄ .

This is because the molecular diameter of ethanol, which is a residual component, is 0.43 nm or more, which is 1.07 times or more the pore diameter of DDR type zeolite 0.40 nm, whereas the molecular diameter of CH ₄ is 0.38 nm, which is the DDR type zeolite. This is because the pore diameter is less than 1.07 times 0.40 nm. Therefore, it was confirmed that when the molecular diameter of the residual component is 1.07 times or more of the pore diameter, the molecular diameter of the gas component is preferably 1.07 times or more of the pore diameter.

Claims (7)

When the first gas component is supplied to the zeolite membrane, the permeation component contained in the liquid mixture that is the separation target of the zeolite membrane is based on the first measured permeation rate at which the first gas component permeates the zeolite membrane. Predicting a first predicted permeation flux that permeates the zeolite membrane;
When a second gas component is supplied to the zeolite membrane, a residual component contained in the liquid mixture permeates the zeolite membrane based on a second actually measured permeation rate at which the second gas component permeates the zeolite membrane. 2 predicting the predicted permeation flux;
With
When the molecular diameter of the permeation component is 0.93 times or less of the pore diameter of the zeolite membrane, the molecular diameter of the first gas component is 0.93 times or less of the pore diameter, and the molecular diameter of the permeation component is the above-mentioned When the pore diameter is greater than 0.93 times and less than 1.07 times, the molecular diameter of the first gas component is greater than 0.93 times the pore diameter and less than 1.07 times,
When the molecular diameter of the residual component is 1.07 times or more of the pore diameter of the zeolite membrane, the molecular diameter of the second gas component is 1.07 times or more of the pore diameter, and the molecular diameter of the residual component is When the pore diameter is greater than 0.93 times and less than 1.07 times, the molecular diameter of the second gas component is greater than 0.93 times the pore diameter and less than 1.07 times.
Method for evaluating the separation performance of zeolite membranes. The molecular diameter of the first gas component is smaller than the molecular diameter of the second gas component;
The method for evaluating the separation performance of a zeolite membrane according to claim 1. Providing the first measured permeation flux and the second measured permeation flux by supplying a mixed gas containing the first gas component and the second gas component to the zeolite membrane,
The method for evaluating the separation performance of a zeolite membrane according to claim 1 or 2. Obtaining the first measured permeation flux by supplying the first gas component to the zeolite membrane;
Obtaining the second measured permeation flux by supplying the second gas component to the zeolite membrane;
A method for evaluating the separation performance of a zeolite membrane according to claim 1 or 2. Heating the zeolite membrane at 200 ° C. or higher before supplying the first gas component or / and the second gas component to the zeolite membrane,
The method for evaluating the separation performance of a zeolite membrane according to claim 3 or 4. The molecular diameter of the second gas component is not more than 1.5 times the inner diameter of the pores.
The method for evaluating the separation performance of a zeolite membrane according to any one of claims 1 to 5. Forming a zeolite membrane having pores on the surface of the porous support; and
When the first gas component is supplied to the zeolite membrane, the permeation component contained in the liquid mixture that is the separation target of the zeolite membrane is based on the first measured permeation rate at which the first gas component permeates the zeolite membrane. Predicting a first predicted permeation flux that permeates the zeolite membrane;
When a second gas component is supplied to the zeolite membrane, a residual component contained in the liquid mixture permeates the zeolite membrane based on a second actually measured permeation rate at which the second gas component permeates the zeolite membrane. 2 predicting the predicted permeation flux;
With
When the molecular diameter of the permeation component is 0.93 times or less of the pore diameter of the zeolite membrane, the molecular diameter of the first gas component is 0.93 times or less of the pore diameter, and the molecular diameter of the permeation component is the above-mentioned When the pore diameter is greater than 0.93 times and less than 1.07 times, the molecular diameter of the first gas component is greater than 0.93 times the pore diameter and less than 1.07 times,
When the molecular diameter of the residual component is 1.07 times or more of the pore diameter of the zeolite membrane, the molecular diameter of the second gas component is 1.07 times or more of the pore diameter, and the molecular diameter of the residual component is When the pore diameter is greater than 0.93 times and less than 1.07 times, the molecular diameter of the second gas component is greater than 0.93 times the pore diameter and less than 1.07 times.
A method for producing a zeolite membrane structure.