Zeolite separation membrane reactor for dehydrogenation of liquid organic hydrogen carrier

Abstract

The present invention relates to a zeolite separation membrane reactor for dehydrogenation of a liquid organic hydrogen carrier. According to the present invention, it is possible to provide a zeolite separation membrane reactor for dehydrogenation of a liquid organic hydrogen carrier, which overcomes the thermodynamic limit of a dehydrogenation reaction by using a zeolite separation membrane reactor filled with a catalyst therein and achieves a conversion rate higher than an equilibrium conversion rate at a low reaction temperature, thereby having high hydrogen separation performance.

Description

Zeolite membrane reactor for dehydrogenation of liquid organic hydrogen carriers

[0001] The present invention relates to a zeolite membrane reactor for dehydrogenation of a liquid organic hydrogen carrier, and more particularly, to a zeolite membrane reactor capable of overcoming the thermodynamic limitations of a liquid organic hydrogen carrier (LOHC) dehydrogenation reaction and achieving a conversion rate higher than the equilibrium conversion rate at a low reaction temperature by using a zeolite membrane reactor in which a catalyst is filled inside a zeolite membrane having high hydrogen separation performance.

[0002] Hydrogen (H2) is a clean energy source that can mitigate carbon emissions and is a key element in addressing environmental issues, including climate change and air pollution, and achieving carbon neutrality [Clark et al., "Single-step hydrogen production from NH3, CH4, and biogas in stacked proton ceramic reactors", Science, 2022, 376, 390-393]. To truly utilize hydrogen, it is crucial to establish safe and economical hydrogen storage and transportation processes.

[0003] To address these issues, liquid organic hydrogen carriers (LOHCs), which exist in a liquid state at room temperature and pressure, have emerged as an alternative approach for storage and transportation. This LOHC process involves the storage and extraction of hydrogen through reversible hydrogenation and dehydrogenation reactions of organic compounds, enabling the safe transport of hydrogen in a liquid state.

[0004] In particular, the methylcyclohexane (MCH) and toluene (Tol) pair is a suitable compound for use as a LOHC material, as it has a high hydrogen content, low toxicity, and a relatively low boiling point, making it an attractive LOHC candidate.

[0005] However, MCH dehydrogenation is endothermic, requiring high reaction temperatures to achieve high MCH conversion. This high temperature can deactivate the catalyst, reducing selectivity and potentially generating undesirable byproducts. To overcome this problem, membrane reactors can be used, offering the advantage of shifting the reaction equilibrium toward the product by selectively separating specific reaction products.

[0006] Consequently, it overcomes thermodynamic reaction limitations, enabling higher conversion rates at lower reaction temperatures. This shifts the equilibrium state toward more hydrogen production by selectively removing only hydrogen through the membrane of the membrane reactor, thereby enabling more economical hydrogen production.

[0007] In order to implement such a membrane reactor, a membrane must be successfully synthesized on the inner surface of a tubular support that serves as the membrane in the membrane reactor configuration. In order to apply this to the equilibrium-limited MCH dehydrogenation reaction, the resulting membrane must have high separation performance for the H2 / Tol mixture. In addition, it is essential to secure technological capabilities for high thermal stability and long-term stability of the membrane that can maintain the separation performance for a long period of time even over a wide temperature range (190-300°C).

[0008] Meanwhile, DDR structure zeolite has a pore size of approximately 0.360.44 nm. 2Hydrogen (0.289 nm) can be separated from methylcyclohexane (0.60 nm) or toluene (0.59 nm) by taking advantage of the difference in molecular size. However, despite the high potential for hydrogen separation, DDR-structured zeolite membranes present challenges for practical industrial and process applications. This is due to the lack of a robust methodology for reproducibly fabricating high-performance DDR-structured zeolite membranes.

[0009] However, a relatively easy and simple method for fabricating a CHA-DDR heterogeneous zeolite membrane has recently been reported. This method utilizes SSZ-13 particles, a CHA-structured zeolite, as seed particles to synthesize a DDR-structured zeolite based on structural compatibility. The heterogeneous zeolite membrane exhibits high CO2 separation permeability for CO2 / CH4 and CO2 / N2 mixtures.

[0010] Accordingly, the present invention aims to provide a zeolite membrane reactor capable of overcoming the thermodynamic limitations of the MCH dehydrogenation reaction and achieving a conversion rate higher than the equilibrium conversion rate at a low reaction temperature.

[0011] The purpose of the present invention is to provide a zeolite membrane reactor for dehydrogenation of a liquid organic hydrogen carrier.

[0012] In addition, another object of the present invention is to provide a zeolite membrane reactor for dehydrogenation of a liquid organic hydrogen carrier, which can overcome the thermodynamic limitations of the dehydrogenation reaction and achieve a high conversion rate at a low reaction temperature.

[0013] According to one aspect of the present invention, embodiments of the present invention provide a zeolite membrane reactor for dehydrogenation of a liquid organic hydrogen carrier, comprising: a reactor in which a dehydrogenation reaction is performed; a reactant inlet provided on one side of the reactor to introduce a reactant into the interior; a product discharge unit provided on the other side of the reactor to discharge at least a portion of a product of the dehydrogenation reaction to the outside; a gas inlet unit provided adjacent to the product discharge unit to introduce a sweep gas into the interior of the reactor; and a gas discharge unit provided adjacent to the reactant inlet unit to discharge at least another portion of the product of the dehydrogenation reaction to the outside of the reactor.

[0014] In one embodiment, a zeolite separation membrane and a catalyst may be provided within the reactor.

[0015] In one embodiment, the zeolite separation membrane may include a tubular support having an internal space; and a zeolite provided on the inside and the inner surface of the support, the zeolite including at least one structure selected from the group consisting of a CHA structure and a DDR structure.

[0016] In one embodiment, the cross-section of the zeolite separation membrane may include a first layer including a CHA structure, a DDR structure, and a support; a second layer provided on the inner surface of the support and including a CHA structure and a DDR structure; and a third layer provided on the second layer and including a DDR structure.

[0017] In one embodiment, the average thickness of the first to third layers may be 0.1 μm to 5.0 μm.

[0018] In one embodiment, the CHA structure may be included in an amount of 5 to 50 parts by weight based on 100 parts by weight of the entire zeolite structure of the first, second, and third layers.

[0019] In one embodiment, the average thickness of the first layer may be 0.1 µm to 1.0 µm, the average thickness of the second layer may be 0.1 µm to 5.0 µm, and the average thickness of the third layer may be 0.1 µm to 5.0 µm.

[0020] In one embodiment, the catalyst comprises a Pt / C catalyst diluted with quartz filled in the internal space of a support provided in the zeolite separation membrane, and may be included in a weight ratio of the Pt / C catalyst: quartz = 1:1 to 10.

[0021] In one embodiment, the size of the quartz may be from 50 μm to 600 μm, and the size of the Pt / C catalyst may be from 50 μm to 500 μm.

[0022] In one embodiment, the support may include one or more of α-alumina, γ-alumina, polypropylene, polyethylene, polytetrafluoroethylene, polysulfone, polyimide, silica, glass, mullite, zirconia, titania, yttria, ceria, vanadia, silicon, stainless steel, carbon, calcium oxide, and phosphorus oxide.

[0023] In one embodiment, the reactor may comprise a reactor that produces toluene and hydrogen (H2) by dehydrogenation of methylcyclohexane (MCH), and has an MCH conversion rate (%) of 30% to 99% at 190 °C to 275 °C.

[0024] In one embodiment, the reactant is at least one of methylcyclohexane, methylcyclopentane, cyclohexane, decalin, perhydro-dibenzyltoluene, dodecahydro-N-ethylcarbazole, 1-methylperhydro indole, 2-methylperhydro indole, 1,2-perhydrodimethyl indole, perhydro-phenazine, and perhydro-2-(n-methylbenzyl pyridine), and the product is hydrogen (H2), toluene, benzene, It may include at least one of naphthalene, dibenzyl toluene, benzyl toluene, N-ethyl carbazole, 1-methylperhydro indole, 2-methylperhydro indole, 1,2-perhydrodimethyl indole, phenazine, and 2-n-methylbenzyl pyridine.

[0025] In one embodiment, the reactor may include a reactor in which a cyclic hydrocarbon is generated into hydrogen (H2) and an aromatic hydrocarbon through a dehydrogenation reaction, the cyclic hydrocarbon and a carrier gas are introduced into the reactant inlet, the product discharge port discharges the cyclic hydrocarbon, the aromatic hydrocarbon, hydrogen (H2), and the carrier gas, the gas inlet port discharges a sweep gas, and the gas discharge port discharges the sweep gas and hydrogen (H2).

[0026] In one embodiment, the carrier gas may include at least one of argon (Ar), nitrogen (N2), and helium (He), and the sweep gas may include at least one of argon (Ar), nitrogen (N2), and helium (He).

[0027] In one embodiment, the inflow rate of the cyclic hydrocarbon is 0.001 mL·min -1 10 mL·min -1 , and the inflow rate of the carrier gas is 1 mL·min -1 Up to 1000 mL·min -1 And, the inflow rate of the above sweep gas is 1 mL·min -1 Up to 1000 mL·min -1 This may include:

[0028] In one embodiment, the CHA structure is prepared from a CHA precursor solution, and the CHA precursor solution includes a first organic structure derivative, SiO2, H2O, a sodium compound, and an aluminum compound, and the first organic structure derivative, SiO2, H2O, the sodium compound, and the aluminum compound are each in a molar ratio of 0.1 to 1000: 100: 100 to 50000: 0 to 500: 0 to 100, and the first organic structure derivative is TMAdaOH (N,N,N-trimethyl adamantylammoniumhydroxide), TMAdaBr (N,N,N-trimethyl adamantylammoniumbromide), TMAdaF (N,N,N-trimethyl adamantylammoniumfluoride), TMAdaCl (N,N,N-trimethyl adamantylammoniumchloride), TMAdaI (N,N,N-trimethyl adamantylammonium iodide), TEAOH (tetraethylammonium hydroxide), TEABr (tetraethylammonium bromide), TEAF (tetraethylammonium fluoride), TEACl (tetraethylammonium chloride), TEAI (tetraethylammoniumiodide), dipropylamine, Cyclohexylamine, TMAOH (Tetramethylammonium hydroxide), BTMAOH (Benzyltrimethylammoniumhydroxide), BTMACl (Benzyltrimethylammoniumchloride), Choline Chloride, NH4F (Ammonium Fluoride), DMCHABr (Dimethylethylcyclohexylammonium bromide), M3CyNOH (Trimethylcyclohexylammoniumhydroxide), Cu-TEPA (Cu 2+coordinated with tetraethylenepentamine) and TMAibOH (Trimethylisobutylammoniumhydroxide).

[0029] In one embodiment, a CHA structure is manufactured using the CHA precursor solution by a hydrothermal synthesis method, and a first growth step of forming seed particles including the CHA structure is included, wherein the hydrothermal synthesis method may include performing the process for 6 to 400 hours and at 100 °C to 250 °C.

[0030] In one embodiment, the first growth step may include synthesizing seed particles including a CHA structure by a hydrothermal synthesis method using the CHA precursor solution, dispersing the seed particles in a solvent to prepare a suspension, impregnating a support in the suspension to coat the seed particles on the surface of the support, drying the support coated with the seed particles, and after drying is complete, heat-treating the support coated with the seed particles at 300 °C to 550 °C for 1 hour to 24 hours.

[0031] In one embodiment, the DDR structure is prepared from a DDR precursor solution, and the DDR precursor solution includes SiO2, a second organic structure derivative, H2O, a sodium compound, and an aluminum compound, wherein the SiO2, the second organic structure derivative, H2O, the sodium compound, and the aluminum compound are each in a molar ratio of 100:1 to 1000:10 to 100000:0 to 500:0 to 100, and the second organic structure derivative is methyltropinium iodide, methyltropinium bromide, methyltropinium fluoride, methyltropinium chloride, methyltropinium hydroxide, quinuclidinium, and TEAOH (tetraethylammonium hydroxide), TEABr (tetraethylammonium bromide), TEAF (tetraethylammonium fluoride), TEACl (tetraethylammonium chloride), TEAI (tetraethylammonium iodide), ethylenediamine, and adamantylamine.

[0032] In one embodiment, the method comprises a second growth step of manufacturing a DDR structure by using the DDR precursor solution to cover the seed particle by a hydrothermal synthesis method, and forming a layered structure including the DDR structure, wherein the hydrothermal synthesis method may be performed for 6 to 400 hours and at a temperature range of 100 °C to 250 °C.

[0033] In one embodiment, after the secondary growth step, a heat treatment step may be further included, and the heat treatment step may include performing the step at a temperature range of 100 °C to 300 °C in an ozone atmosphere.

[0034] In one embodiment, the average pore diameter of the support is 0.7 μm to 0.9 μm, the zeolite separation membrane has a pore size of 0.36 nm to 0.44 nm, and may contain 1 wt% or less of adamantylamine inside the pores of the separation membrane.

[0035] In one embodiment, the zeolite membrane has a density of 1x10 -9 1x10 -5 mol·m -2 ·s -1 ·Pa -1 It may include having a hydrogen permeability of .

[0036] In one embodiment, the CHA precursor solution and the DDR precursor solution each include Si and Al, and the CHA structure may include a Si:Al molar ratio reference value of 100:0 to 10, and the DDR structure may include a Si:Al molar ratio reference value of 100:0 to 10.

[0037] In one embodiment, the purity of hydrogen discharged from the reactor may be 99% or higher, and the separation factor may be 100 or higher.

[0038] According to the present invention as described above, a zeolite membrane reaction device for dehydrogenation of a liquid organic hydrogen carrier can be provided.

[0039] In addition, according to the present invention, a zeolite membrane reactor for dehydrogenation of liquid organic hydrogen carriers (LOHC) can be provided, which overcomes the thermodynamic limitations of the LOHC dehydrogenation reaction by using a zeolite membrane reactor in which a catalyst is filled inside a zeolite membrane having high hydrogen separation performance, and achieves a conversion rate higher than the equilibrium conversion rate at a low reaction temperature.

[0040] Figure 1 is a process diagram of a zeolite separation membrane reaction device for dehydrogenation of a liquid organic hydrogen carrier according to one embodiment of the present invention.

[0041] FIG. 2 is a drawing of a zeolite separation membrane for comparing the H2 separation effect according to one embodiment of the present invention.

[0042] Figure 3 is an SEM image and XRD pattern of a zeolite separation membrane (Z) according to one embodiment of the present invention.

[0043] Figures 4 and 5 are graphs of hydrogen separation performance according to one embodiment of the present invention.

[0044] FIG. 6 is a graph showing the equilibrium MCH conversion rate in a quartz tube reactor (Q) according to one embodiment of the present invention.

[0045] Figure 7 is Z and Z according to one embodiment of the present invention. out This graph shows the equilibrium MCH conversion rate in a membrane-based reactor.

[0046] Figure 8 is a graph showing the MCH conversion rate of the G and Z membrane reactors according to one embodiment of the present invention.

[0047] FIGS. 9 to 11 are graphs showing molar flow rates according to temperature and pressure of G and Z membrane reactors according to one embodiment of the present invention.

[0048] Figure 12 is a graph showing the molar flow rate according to the reaction temperature of the G and Z zeolite separation membrane reactors according to one embodiment of the present invention.

[0049] Figure 13 is a graph showing the molar flow rate and Tol yield according to the reaction temperature of a G zeolite separation membrane reactor according to one embodiment of the present invention.

[0050] Figure 14 is a graph showing the H2molar flow rate of a Z zeolite separation membrane reactor according to one embodiment of the present invention.

[0051] FIG. 15 is a graph of the MCH dehydrogenation reaction performance of the G and Z zeolite membrane reactors in vacuum mode according to one embodiment of the present invention.

[0052] FIG. 16 is a time-on-stream function graph for the MCH dehydrogenation reaction of a Z zeolite membrane reactor according to temperature change in vacuum mode according to one embodiment of the present invention.

[0053] Specific details of other embodiments are included in the detailed description and drawings.

[0054] The advantages and features of the present invention, and the methods for achieving them, will become clear with reference to the embodiments described in detail below together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but can be implemented in various different forms, and unless otherwise specified in the following description, all numbers, values, and / or expressions expressing components, reaction conditions, and contents of components in the present invention are to be understood as being modified in all cases by the term "about" because such numbers are approximations that reflect various uncertainties of measurement that occur in obtaining such values, among other things. In addition, when a numerical range is disclosed herein, such range is continuous and includes every value from the minimum value to the maximum value inclusive, unless otherwise indicated. Furthermore, when such a range refers to an integer, every integer from the minimum value to the maximum value inclusive, unless otherwise indicated, is included.

[0055] Additionally, when a range is described for a variable in the present invention, it will be understood that the variable includes all values ​​within the described range including the described endpoints of the range. For example, the range "5 to 10" will be understood to include the values ​​5, 6, 7, 8, 9, and 10, as well as any subranges such as 6 to 10, 7 to 10, 6 to 9, 7 to 9, etc., and also any value between integers that fall within the described range, such as 5.5, 6.5, 7.5, 5.5 to 8.5, and 6.5 to 9. For example, a range of "10% to 30%" would be understood to include values ​​such as 10%, 11%, 12%, 13%, etc., and all integers up to and including 30%, as well as any subranges such as 10% to 15%, 12% to 18%, 20% to 30%, and any value between reasonable integers within the stated range, such as 10.5%, 15.5%, 25.5%, etc.

[0056] Figure 1 is a drawing showing a zeolite separation membrane reaction device for dehydrogenation of a liquid organic hydrogen carrier according to one embodiment of the present invention.

[0057] Referring to FIG. 1, according to an embodiment of the present invention, a zeolite membrane reactor (1) for dehydrogenation of a liquid organic hydrogen carrier comprises: a reactor (100) in which a dehydrogenation reaction is performed; a reactant inlet (110) provided on one side of the reactor to introduce reactants into the interior; a product discharge unit (120) provided on the other side of the reactor to discharge at least a portion of a product of the dehydrogenation reaction to the outside; a gas inlet unit (130) provided adjacent to the product discharge unit to introduce a sweep gas into the interior of the reactor; and a gas discharge unit (140) provided adjacent to the reactant inlet unit to discharge at least another portion of the product of the dehydrogenation reaction to the outside of the reactor.

[0058] A zeolite separation membrane (150) and a catalyst (160) may be provided within the above reactor (100).

[0059] The above zeolite separation membrane (150) may include a tubular support having an internal space; and a zeolite provided on the inside and the inner surface of the support and including at least one structure among a CHA structure and a DDR structure.

[0060] The cross-section of the above zeolite separation membrane (150) may include a first layer including a CHA structure, a DDR structure, and a support; a second layer provided on the inner surface of the support and including a CHA structure and a DDR structure; and a third layer provided on the second layer and including a DDR structure.

[0061] The average thickness of the first to third layers may be 0.1 ㎛ to 5.0 ㎛. When the average thickness of the first to third layers is less than 0.1 ㎛, it is difficult to obtain high purity H2, and in particular, separation is difficult in the case of a mixed gas, which is a problem. When the average thickness exceeds 5.0 ㎛, the size and processing cost of the device using the zeolite separation membrane increase, and the content of the mixed gas that can be processed at one time may also decrease. Specifically, it is preferable that the average thickness of the first to third layers is 0.5 ㎛ to 3.0 ㎛.

[0062] With respect to 100 parts by weight of the total zeolite structure of the first, second, and third layers, the CHA structure may be included in an amount of 5 to 50 parts by weight. If the CHA structure is less than 5 parts by weight, it may be difficult to sufficiently form a seed structure for forming a zeolite structure, and if it is more than 50 parts by weight, the proportion of the DDR structure may be too small, which may cause a problem in that the gas separation ability may not be effectively improved. Specifically, the CHA structure is preferably included in an amount of 5 to 35 parts by weight.

[0063] The average thickness of the first layer may include 0.1 ㎛ to 1.0 ㎛. If the average thickness of the first layer is less than 0.1 ㎛, it may be difficult to form a stable CHA seed structure, making it difficult to grow the second layer on the first layer. If it exceeds 1.0 ㎛, the overall thickness of the zeolite separation membrane may unnecessarily increase. Specifically, the average thickness of the first layer is preferably 0.1 ㎛ to 0.5 ㎛.

[0064] The average thickness of the second layer may include 0.1 ㎛ to 5.0 ㎛. If the average thickness of the second layer is less than 0.1 ㎛, the DDR structure may be too thin to be synthesized into the CHA seed structure, making structure formation difficult. If it exceeds 5.0 ㎛, the overall thickness of the zeolite separation membrane may unnecessarily increase. Specifically, the average thickness of the second layer is preferably 0.1 ㎛ to 3.0 ㎛.

[0065] The average thickness of the third layer may be from 0.1 μm to 5.0 μm. If the average thickness of the third layer is less than 0.1 μm, it is difficult to form the DDR structure, and thus the separation membrane cannot properly perform its function. If it exceeds 5.0 μm, the overall thickness of the zeolite separation membrane may unnecessarily increase. Specifically, the average thickness of the third layer is preferably from 0.1 μm to 3.0 μm.

[0066] By providing the first, second and third layers with the aforementioned thickness, high purity H2 can be separated.

[0067] The above catalyst (160) includes a Pt / C catalyst diluted with quartz filled in the internal space of a support provided in the zeolite separation membrane, and may be included in a weight ratio of the Pt / C catalyst: quartz = 1:1 to 10.

[0068] The size of the above quartz may be 50 ㎛ to 600 ㎛, and the size of the above Pt / C catalyst may be 50 ㎛ to 500 ㎛.

[0069] The support may be provided in a tubular or tube shape, and a plurality of tubular separation membranes may be connected to each other to be used for upgrading biogas or separating mixed gases. By providing the support in a tubular or tube shape, the zeolite separation membrane can be designed in the form of a single cell, or can be manufactured in the form of a module composed of a plurality of cells, which can be more efficient in actual process application. By separating the mixed gas through the internal cavities of the tubular separation membrane, the separation efficiency of the gas can be further improved.

[0070] Specifically, the zeolite separation membrane (150) can form seed particles containing a CHA structure on the inside and inside surface of the support. By secondary growth of a zeolite containing a DDR structure using the seed particles, a zeolite separation membrane containing the first layer, the second layer, and the third layer can be formed.

[0071] The support may include at least one of α-alumina, γ-alumina, polypropylene, polyethylene, polytetrafluoroethylene, polysulfone, polyimide, silica, glass, mullite, zirconia, titania, yttria, ceria, vanadia, silicon, stainless steel, carbon, calcium oxide, and phosphorus oxide.

[0072] The above reactor (100) may include a reactor that produces toluene and hydrogen (H2) by dehydrogenation of methylcyclohexane (MCH) and has an MCH conversion rate (%) of 30% to 99% at 190 °C to 275 °C.

[0073] The above reactants are at least one of methylcyclohexane, methylcyclopentane, cyclohexane, decalin, perhydro-dibenzyltoluene, dodecahydro-N-ethylcarbazole, 1-methylperhydro indole, 2-methylperhydro indole, 1,2-perhydrodimethyl indole, perhydro-phenazine, and perhydro-2-(n-methylbenzyl pyridine), and the products are hydrogen (H2), toluene, benzene, naphthalene, It may include at least one of dibenzyl toluene, benzyl toluene, N-ethyl carbazole, 1-methylperhydro indole, 2-methylperhydro indole, 1,2-perhydrodimethyl indole, phenazine, and 2-n-methylbenzyl pyridine.

[0074] In the above reactor, a cyclic hydrocarbon is generated into hydrogen (H2) and an aromatic hydrocarbon through a dehydrogenation reaction, the cyclic hydrocarbon and a carrier gas are introduced into the reactant inlet, the cyclic hydrocarbon, the aromatic hydrocarbon, hydrogen (H2), and a carrier gas are discharged into the product discharge port, the gas inlet port may include a sweep gas introduced into, and the gas discharge port may include a sweep gas and hydrogen (H2) discharged from.

[0075] The carrier gas may include one or more of argon (Ar), nitrogen (N2), and helium (He).

[0076] The above sweep gas may include at least one of argon (Ar), nitrogen (N2), and helium (He).

[0077] The inflow rate of the above cyclic hydrocarbon is 0.001 mL·min -1 10 mL·min -1 , and the inflow rate of the carrier gas is 1 mL·min -1 Up to 1000 mL·min -1 And, the inflow rate of the above sweep gas is 1 mL·min -1 Up to 1000 mL·min -1 This may include:

[0078] The above CHA structure can be manufactured using a CHA precursor solution.

[0079] The above CHA precursor solution may include a first organic structure derivative, SiO2, H2O, a sodium compound, and an aluminum compound.

[0080] The first organic structure derivative, SiO2, H2O, sodium compound, and aluminum compound may each be included in a molar ratio of 0.1 to 1000: 100: 100 to 50000: 0 to 500: 0 to 100. Specifically, the first organic structure derivative, SiO2, H2O, sodium compound, and aluminum compound may each be in a molar ratio of 1 to 100: 100: 500 to 30000: 5 to 50: 0.5 to 20, and more specifically, 20: 100: 1600: 20: 5.

[0081] 상기 제1유기구조유도체는 TMAdaOH (N,N,N-trimethyl adamantylammoniumhydroxide), TMAdaBr (N,N,Ntrimethyl adamantylammoniumbromide), TMAdaF (N,N,N-trimethyl adamantylammoniumfluoride), TMAdaCl (N,N,N-trimethyl adamantylammoniumchloride), TMAdaI (N,N,N-trimethyl adamantylammonium iodide), TEAOH (tetraethylammonium hydroxide), TEABr (tetraethylammonium bromide), TEAF (tetraethylammonium fluoride), TEACl (tetraethylammonium chloride), TEAI (tetraethylammoniumiodide), 디프로필아민 (dipropylamine), 사이클로헥실아민(cyclohexylamine), TMAOH (Tetramethylammonium hydroxide), BTMAOH (Benzyltrimethylammoniumhydroxide), BTMACl (Benzyltrimethylammoniumchloride), 염화 콜린(Choline Chloride), NH4F (Ammonium Fluoride), DMCHABr (Dimethylethylcyclohexylammonium bromide), M3CyNOH (Trimethylcyclohexylammoniumhydroxide), Cu-TEPA (Cu 2+ coordinated with tetraethylenepentamine) 및 TMAibOH (Trimethylisobutylammoniumhydroxide) 중 어느 하나 이상을 포함할 수 있다.

[0082] A method for producing a CHA structure using the above CHA precursor solution by a hydrothermal synthesis method, and including a first growth step of forming seed particles including the CHA structure, wherein the hydrothermal synthesis method may include performing the method for 6 to 400 hours and at 100 °C to 250 °C.

[0083] The above first growth step may include synthesizing seed particles including a CHA structure by a hydrothermal synthesis method using the CHA precursor solution, dispersing the seed particles in a solvent to prepare a suspension, impregnating a support in the suspension to coat the seed particles on the surface of the support, drying the support coated with the seed particles, and after drying is complete, heat-treating the support coated with the seed particles at 300 °C to 550 °C for 1 to 24 hours.

[0084] The above DDR structure can be manufactured using a DDR precursor solution.

[0085] The above DDR precursor solution may include SiO2, a second organic structure derivative, H2O, a sodium compound, and an aluminum compound.

[0086] The above SiO2, the second organic structure derivative, H2O, the sodium compound, and the aluminum compound may each have a molar ratio of 100:1 to 1000:10 to 100000:0 to 500:0 to 100. Specifically, the above SiO2, the second organic structure derivative, H2O, the sodium compound, and the aluminum compound may each have a molar ratio of 100:10 to 800:500 to 30000:0 to 50:0 to 20, and more specifically, may be 100:450:11240:0:0.

[0087] The second organic structure derivative may include at least one of methyltropinium iodide, methyltropinium bromide, methyltropinium fluoride, methyltropinium chloride, methyltropinium hydroxide, quinuclidinium, TEAOH (tetraethylammonium hydroxide), TEABr (tetraethylammonium bromide), TEAF (tetraethylammonium fluoride), TEACl (tetraethylammonium chloride), TEAI (tetraethylammonium iodide), ethylenediamine, and adamantylamine.

[0088] Specifically, the second organic structure derivative may be used by combining two or more substances, and more specifically, may be used by combining adamantylamine and one or more other substances. For example, the second organic structure derivative may include adamantylamine and ethylenediamine, and when the adamantylamine and ethylenediamine are used in combination, the ethylenediamine may be used in a molar ratio of 5 to 20 times that of the adamantyl amine. In addition, the adamantylamine and ethyleneadiamine may be used in combination in a molar ratio of 10 to 100: 50 to 1000.

[0089] The method may include manufacturing a DDR structure by using the above DDR precursor solution to cover the seed particle through a hydrothermal synthesis method, and forming a layered structure including the DDR structure through a second growth step, wherein the hydrothermal synthesis method may be performed for 6 to 400 hours and at a temperature of 100 °C to 250 °C.

[0090] After the above secondary growth step, a heat treatment step may be further included, and the heat treatment step may include performing it in an ozone atmosphere at a temperature range of 100 °C to 300 °C.

[0091] The average pore diameter of the support is 0.7 μm to 0.9 μm, the zeolite separation membrane has a pore size of 0.36 nm to 0.44 nm, and may contain 1 wt% or less of adamantylamine inside the pores of the separation membrane.

[0092] The above zeolite membrane is 1x10 -9 1x10 -5 mol·m -2 ·s -1 ·Pa -1 It may include having a hydrogen permeability of .

[0093] The above CHA precursor solution and DDR precursor solution each contain Si and Al, and the CHA structure may have a Si:Al molar ratio reference value of 100:0 to 10, and the DDR structure may have a Si:Al molar ratio reference value of 100:0 to 10.

[0094] The purity of the hydrogen discharged from the above reactor may be 99% or higher, and the separation factor may be 100 or higher. Specifically, it may be preferable that the purity of the hydrogen be 99.9% or higher, and the separation factor be 400 or higher.

[0095]

[0096] Hereinafter, examples and comparative examples of the present invention are described. However, the following examples are only preferred embodiments of the present invention and the scope of the present invention is not limited by the following examples.

[0097]

[0098] (Manufacture of examples and comparative examples)

[0099] 1. Preparation of the zeolite separation membrane of the present invention

[0100] Synthesis of CHA (SSZ-13) seed particles

[0101] CHA (SSZ-13) seed particles were synthesized as follows. N,N,N-Trimethyl-1-adamantylammonium hydroxide (TMAdaOH, 25 wt%, product number: T3821, SACHEM, Inc.) and sodium hydroxide (NaOH≥98%, product number: S5881, Sigma-Aldrich) were added to a 250 mL polypropylene (PP) bottle containing deionized (DI) water and mixed. The mixture was stirred for approximately 20 min to form a mixture, and then silica source (LUDOX® HS-40 colloidal silica, 40 wt% suspension in H2O, and product number: 420816, Sigma-Aldrich) was slowly added to the mixture while stirring.

[0102] The resulting mixture was stirred at room temperature for 48 h, and then transferred to a Teflon-lined (ca. 45 mL) stainless steel autoclave in an oven preheated to 160 °C (PL-HC_250, Pluskolab, Republic of Korea) and subjected to hydrothermal reaction at 45 rpm for 7 days. After hydrothermal reaction, the autoclave was rapidly cooled with tap water to stop the reaction, and the synthesized particles were recovered through five repetitions of centrifugation, decanting, and redispersion with deionized water. The recovered particles were dried overnight in an oven at 70 °C and then calcined at 550 °C for 12 h in a box-type furnace (CRF-M20-UP, Pluskolab, Republic of Korea) with the temperature increased at 1 °C / min.

[0103]

[0104] Formation of CHA (SSZ-13) seed layer inside the support

[0105] Zeolite membranes were prepared using an asymmetric α-alumina tubular support (outer diameter: 12 mm, inner diameter: 8 mm, length: 90 mm, porosity: 39%, average pore diameter: 0.86 μm; FINETECH Co., Ltd., Republic of Korea). Prior to the synthesis of the zeolite membrane, the cells at both ends (approximately 2 cm) of the tubular support were sealed by glazing with an impermeable material (IN1001 Envision Glazes, Duncan Ceramics, USA). After the glazing was completed, seed particles of SSZ-13 (standard oil synthetic zeolite-13, SSZ-13; chabazite (CHA) type), a zeolite containing a CHA structure, were synthesized. The Si to Al ratio of the prepared SSZ-13 seed particles was found to be 20±2 on average.

[0106] The prepared SSZ-13 seed particles were coated on the inner surface of an α-alumina tubular support using a dip coating method. Specifically, the prepared SSZ-13 seed particles were added to a 250 mL polypropylene (PP) bottle containing ethanol, and then sonicated for 20 minutes using an ultrasonic processor (UC-10, JeioTech Co. Ltd., Republic of Korea) to prepare a suspension. The prepared suspension contained 0.75 g of seed particles per 1 L of ethanol. To apply the dip coating method, the suspension (approximately 50 mL) was transferred to a 50 mL graduated cylinder. At this time, the α-alumina tubular support was dip coated using a dip coater (ZID-6A, Jaesung Engineering Co., Republic of Korea).

[0107] The α-alumina tubular support was moved vertically downward so that it was completely immersed in the suspension containing SSZ-13 seed particles. After immersion for approximately 30 seconds, the α-alumina tubular support was raised to the initial position and dried at room temperature for approximately 30 seconds. This dip coating process was repeated 14 times in total to form a seed layer composed of seed particles with a uniform and dense shape. The dip coating process was performed 7 times on one side of the α-alumina tubular support, and then the α-alumina tubular support was turned over and 7 times on the other side of the α-alumina tubular support. At this time, in order to prevent the seed particles from being coated on the inner surface of the α-alumina tubular support, a parafilm (parafilm, PM996, Bemis Co., Inc., USA) was attached to the bottom surface of each.

[0108] After the dip coating was completed, the seed particle-coated α-alumina tubular support was separated from the dip coater and dried at room temperature for approximately 30 min. Subsequently, the seed particle-coated α-alumina tubular support was placed in a box-type furnace (CRF-M20-UP, Pluskolab, Korea) and fired at 450 °C for 4 h while increasing the temperature at 1 °C / min.

[0109]

[0110] DDR-synthesized and grown separator on a CHA (SSZ-13) seed layer

[0111] Ethylenediamine (EDA; E26266, ≥99%, Sigma-Aldrich) was placed in a PP reactor, and 1-adamantylamine (ADA; H30076, 98%, Alfa Aesar), an organic structure-directing agent (OSDA) for zeolite synthesis with a DDR structure, was added thereto. The PP reactor containing ethylenediamine and 1-adamantylamine was homogenized by sonication for 20 min. After ADA was completely dissolved in EDA, deionized (DI) water was rapidly added to the mixture. Immediately after adding DI water to the PP reactor, the solution became opaque and was prepared as a suspension.

[0112] Subsequently, the prepared suspension was mixed for 1 hour using a shaker machine (Si-300R, JeioTech Co. Ltd., South Korea). After mixing was completed, the prepared suspension was placed in an oil bath heated to approximately 95 °C and stirred using a magnetic bar for 3 hours until the opaque mixture became transparent. After heating to approximately 95 °C, the PP reactor was removed from the oil bath and cooled in an ice water bath. While cooling, the solution was stirred using a magnetic bar for approximately 20 minutes. Subsequently, fumed silica (CAB-O-SIL M5, Cabot Corp., USA) was added to the cooled mixture. The prepared mixture was further mixed using a shaker machine at room temperature for 12 hours. The final molar composition of the DDR synthetic precursor manufactured in this way was found to be 100:47:404:11240 (SiO2: ADA: EDA: H2O).

[0113] The DDR structure was synthesized from the CHA seed layer as follows. Approximately 90 mL of the DDR synthesis precursor was added to a Teflon liner (total volume: approximately 120 mL). Then, an α-alumina tubular support coated with seed particles was placed at an angle within the Teflon liner. The Teflon liner was placed in an autoclave made of stainless steel and sealed. The autoclave was transferred to a convection oven (PL_HV_250, Pluskolab, Korea) preheated to 160 °C, and hydrothermal synthesis was performed under static conditions. After performing hydrothermal synthesis for one day, the autoclave was cooled with tap water, and the zeolite membrane synthesized on the tubular support was taken out as a sample, placed in a 500 mL beaker filled with deionized water, and washed for 12 h. Subsequently, the sample was placed in a dry oven (HB-502M, Pluskolab, Korea) at 70 °C and dried.

[0114] The above dried tubular zeolite membrane was heat-treated at 0.2 °C / min in a tubular furnace (Scientech, Korea) in a quartz tube (outer diameter 50 mm, wall thickness 2 mm), and then at 250 °C for 40 h with an ozone (O3) stream at 200 mL / min. The ozone stream was configured to contain 5 vol% ozone to balance the pure oxygen, and in particular, the ozone stream was generated by flowing pure oxygen gas (99.9% purity) at a rate of 1000 mL / min from an ozone generator (OZE-020, Ozone Engineering Co., Ltd., Korea).

[0115] FIG. 2 is a diagram of a membrane for comparing the H2 separation effect according to one embodiment of the present invention. Referring to FIG. 2, in order to compare the H2 separation effect for the MCH dehydrogenation reaction, an impermeable tubular support was manufactured by glazing the entire outer surface with the aforementioned glaze material. For convenience, the unglazed membrane of the present invention prepared on the tubular support is denoted as Z, and the impermeable membrane is denoted as G.

[0116]

[0117] 2. Characteristic evaluation

[0118] SEM images were obtained using a field emission scanning electron microscope (FE-SEM; S-4800, Hitachi Ltd., Japan). Before obtaining SEM images, Pt was coated on each powder and membrane sample using an E-1045 ion sputter (generated at 30 mA for 30 s) (Hitachi Ltd., Japan).

[0119] X-ray diffraction (XRD) patterns were recorded using a D / Max-2500V / PC X-ray diffractometer (Rigaku Co., Japan) with CuKα radiation (λ = 0.154 nm). For accurate comparison, simulated XRD patterns of CHA and DDR zeolites were confirmed using Mercury software (downloadable from the Cambridge Crystallographic Data Center website, http: / www.ccdc.cam.ac.uk). Each crystal information file was downloaded from the International Zeolite Association (IZA) website (http: / www.iza-online.org).

[0120]

[0121] 3. Measurement of separation performance

[0122] Considering that the ratio of stoichiometric coefficients of H2 and Tol in the MCH dehydrogenation reaction is 3:1, the H2 / Tol separation ability of the manufactured zeolite membrane (Z) was evaluated using a feed mixture with a molar ratio of 3:1. Similarly, in the H2 / MCH separation test, the feed mixture had a molar ratio of 3:1. The performance of Z was evaluated in terms of permeability, separation coefficient, and molar flux at temperatures from 190 °C to 300 °C. For the separation performance measurement, argon (Ar) gas was introduced at a flow rate of 50 mL·min. -1 was used as a sweep gas at a flow rate of , and the total pressure was maintained at 1 bar.

[0123] Additionally, H2 / Tol separation performance experiments were performed at a constant temperature (220 °C) and different total feed pressures (1–3 bar). The molar flow rate of H2 gas was analyzed by analyzing the molar composition of molecules on the permeate side using a gas chromatograph (YL 6500 GC, Youngin Chromass, Korea). A vacuum pump was used to continuously inject molecules on the permeate side into the gas chromatograph equipped with a thermal conductivity detector (TCD). The flow rates of Tol and MCH were measured on both sides using an online gas chromatograph (GC) equipped with a flame ionization detector (FID).

[0124] In addition, for GC analysis of the molar composition on the permeate side, methane (CH4, 10 mL·min -1 ) was used as an internal standard. The log-mean average pressure drop was used to calculate the permeability along the axial direction of the tubular membrane.

[0125]

[0126] 4. Reaction device using the zeolite separation membrane of the present invention

[0127] FIG. 1 is a process diagram of a zeolite separation membrane reactor for dehydrogenation of a liquid organic hydrogen carrier according to one embodiment of the present invention, and FIG. 2 is a diagram of a zeolite separation membrane for comparing the H2 separation effect according to one embodiment of the present invention.

[0128] Referring to Figures 1 and 2, zeolites (Z and Z out ) and impermeable (G) membranes were used in the MR and packed bed reactors, respectively. The MCH dehydrogenation reaction was performed using a catalyst loaded with 5 wt% Pt on activated carbon (150-250 μm range and product number: 19523, Alfa Aesar) and quartz sand (200-300 μm range and product number: 274739, Sigma-Aldrich).

[0129] The internal space of the tubular membrane sample (i.e., Z, Z out , and G) to fill the catalyst, quartz wool was placed on the bottom and a mixture of Pt / C and quartz sand was added. Quartz wool was also placed on the top to fix the mixed particles. For comparison, the MCH dehydrogenation reaction was also performed in a quartz reactor (hereinafter denoted as Q; outer diameter: 9.6 mm and inner diameter: 6.9 mm), and the Pt / C particles were loaded on the quartz wool in the center of the quartz tube reactor.

[0130] In the membrane reactor, MCH feed (0.01 mL·min in liquid form) -1 ) was continuously supplied to the reactor by Ar. The MCH liquid was injected by a high-pressure pump (SP930D, YL Instrument Co., Ltd., Korea) and vaporized by heating the tube line to 200°C using a temperature controller (UP35A, Yokogawa, Japan). In sweep mode, Ar was supplied as carrier gas (10 mL min) using a mass flow controller (MFC, High Tech, Bronkhorst). -1 ) and sweep gas (50 mL·min -1) was used. The reaction temperature and pressure on the reactor feed side were controlled using a temperature controller and a back pressure controller.

[0131] Weight hourly space velocity (WHSV) is the mass flow rate of MCH (7.7 mg·min -1 ) was obtained by dividing by the mass of Pt / C, and in this experiment, the WHSV was adjusted by changing the amount of Pt / C. (Catalyst weights of 0.222, 0.3, 0.461, and 1 g were WHSV 35, 26, 17, and 7.7 mg·g, respectively. -1 ·min -1 )

[0132] During the dehydrogenation reaction of MCH, the molar flow rates of MCH and products (H2 and Tol) on the residue and permeate sides were measured as described in the separation performance measurement experiment above. For high temperature experiments (i.e. ≥ 350 °C), propane (10 mL min) was used instead of methane, which is produced as a by-product under these conditions. -1 ) was used as the internal gas. To ensure reliability, the MCH dehydrogenation reaction was performed three times.

[0133] For performance evaluation, MCH conversion and Tol yield were calculated using equations (1) and (2), respectively.

[0134] (1)

[0135] (2)

[0136] Here, F MCH,in is the molar flow rate of MCH in the inlet stream fed to the reactor and F MCH, out and F Tol,out are the molar flow rates of MCH and Tol in the outlet stream leaving the reactor.

[0137] The equilibrium MCH conversion rate was calculated as follows:

[0138] First, the equilibrium limit of the reaction rate is given by equation (3):

[0139] (3)

[0140] Here, r, k, p i , and K eq,T are the reaction rate, reaction rate constant, partial pressure of components (i = MCH, Tol, or H2), and equilibrium constant, respectively.

[0141] In particular, the equilibrium constant (K) at a given temperature (T) eq, T ) can be calculated based on the Van't Hoff formula (4),

[0142] (4)

[0143] Here, the pre-exponential factor is 650 K (K eq, 650 [K] : 3600 bar 3 ) was obtained from the literature (T. Schildhauer, E. Newson, S. Muller, The Equilibrium Constant for the Methylcyclohexane-Toluene System, J. Catal., 198 (2001) 355-358.).

[0144] Since the reaction rate is 0 at equilibrium, the equilibrium constant obtained using equation (3) is shown in equation (5) below.

[0145] (5)

[0146] Therefore, the equilibrium MCH transformation (X MCH ) was calculated as a function of temperature and used as a standard.

[0147]

[0148] 5. H2 / Tol separation performance of zeolite membrane in vacuum mode and configuration of membrane reactor for MCH dehydrogenation reaction

[0149] In order to measure the H2 / Tol separation performance of Z and to perform the MCH dehydrogenation reaction in the membrane reactor, the vacuum mode was used in addition to the sweep mode.

[0150] At this time, the total pressure on the permeate side was approximately 0.03 bar, which was achieved using a vacuum pump (N840G, KNF, Germany), the total supply pressure was maintained at 1 bar, and other operating parameters for H2 / Tol separation and MCH dehydrogenation were the same as those used in the sweep mode.

[0151]

[0152] (Evaluation results of implementation examples and comparative examples)

[0153] 1. Characteristics of zeolite membrane (Z)

[0154] Figure 3 is an SEM image and XRD pattern of a zeolite separation membrane (Z) according to one embodiment of the present invention.

[0155] Referring to Figure 3, the DDR zeolite membrane grown heterogeneously on the CHA seed layer is formed on the inside of the α-alumina tubular support, and is formed on the outer surface, Z. out , respectively. The SEM images are shown in (a) and (b), and the XRD pattern is shown in (c). Specifically, (a1) and (a2) are cross-sectional SEM images of Z, and (b1) and (b2) are Z out This is a cross-sectional SEM image.

[0156] According to the scanning electron microscope (SEM) images shown in (a) and (b) above, Z and Z out All were continuous on the tubular support, and the pyramidal spike-like particles appeared similar to the pure DDR film. Z and Z out They have similar membrane thicknesses of approximately 2.7 μm and 2.1 μm, respectively, and are expected to exhibit similar separation performance.

[0157] The X-ray diffraction measurement (XRD) pattern of the above (c) is Z and Z outIt confirms that the zeolite membrane contains a significant amount of DDR zeolite and some CHA zeolite. The reaction peak of CHA zeolite (101) is indicated by an arrow. This indicates that a zeolite membrane was synthesized. A small amount of CHA zeolite component appeared as a result of the CHA seed layer (approximately 0.2-1 μm) remaining in the final zeolite membrane (located approximately 2-3 μm from b1-b2). SEM and XRD analyses showed that an intact zeolite membrane composed mostly of DDR type zeolite was well formed on the inner and outer surfaces of the α-alumina tubular support.

[0158]

[0159] 2. Separation performance of zeolite membrane (Z)

[0160] Figure 4 is a graph of hydrogen separation performance according to one embodiment of the present invention.

[0161] Referring to Fig. 4, the ability of the zeolite membrane (Z) to separate H2 from the reactants and products of the MCH dehydrogenation reaction was evaluated. (a) H2 / Tol and (b) H2 / MCH mixed feeds were used at different temperatures (i.e., 190, 220, 250, 275, and 300 °C) at the same pressure (1 bar) using argon (Ar) as a sweep gas at a flow rate of 50 mL·min. -1 When performed, (a1) and (b1) represented the separation factor (SF) of H2, and (a2) and (b2) represented the purity of H2.

[0162] In (a1), the separation factor (SF) of H2 from 190 °C to 300 °C was approximately 300, indicating a high separation factor, and in (a2), the H2 purity was approximately 99.90%. This indicates that the zeolite separation membrane (Z) is a separation membrane with suitable separation performance for use in a separation membrane reactor for selectively separating hydrogen.

[0163] In addition, looking at (b1) and (b2), the separation performance of Z for the H2 / MCH mixture was comparable to that for the H2 / Tol mixture. Specifically, in (b1), the separation factor (SF) of H2 / MCH was approximately 400, and in (b2), the H2 purity was approximately 99.92%.

[0164] The slight difference in the separation factors of H2 / MCH and H2 / Tol may be due to the molecular sizes of MCH and Tol (approximately 0.60 and 0.59 nm, respectively), and it was found that the H2 / Tol separation performance of Z can be used as a measure to evaluate the separation of the main components (MCH, H2, Tol) of the MCH dehydrogenation reaction.

[0165] Figure 5 is a graph of hydrogen separation performance according to one embodiment of the present invention.

[0166] Referring to Fig. 5, the ability of a zeolite membrane (Z) to separate H2 at different pressures (i.e., 1 to 3 bar) at the same temperature (220 °C) in the H2 / Tol feed was evaluated. This was conducted to determine (a) the separation factor (SF) and (b) the purity of H2 according to the increase in pressure within the reactor.

[0167] Looking at (a), it can be seen that the separation factor (SF) of H2 decreases from 341 to 155 as the pressure increases from 1 bar to 3 bar, and looking at (b), it can be seen that the purity of H2 decreases from 99.90% to 99.79%. This is because Tol can preferentially permeate through the non-zeolite region of the membrane at high pressure despite the low defect density of Z, and as shown in (b), the molar flux should be proportional to the increase in total pressure, which can effectively remove H2 from the product stream and shift the equilibrium state toward the product in the configuration of the membrane reactor.

[0168]

[0169] 3. Z membrane reactor for dehydrogenation of MCH

[0170] Figure 6 is a graph showing the equilibrium MCH conversion rate in a quartz tube reactor (Q) according to one embodiment of the present invention, and Figure 7 is a graph showing Z and Z according to one embodiment of the present invention. out This is a graph showing the equilibrium MCH conversion rate in a membrane reactor, and FIG. 8 is a graph showing the MCH conversion rate of the G and Z membrane reactors according to one embodiment of the present invention.

[0171] In the above figure 6, a high WHSV of 43 mg·g in the temperature range of 170-288 °C in the quartz tube reactor (Q) -1 ·min -1 The MCH conversion in was consistent with the equilibrium value calculated by the above calculation formula (5).

[0172] In the above figure 7, Z and Z were used to investigate the possibility of enhanced mass transfer to the permeate side of the generated H2. out A membrane reactor was used and comparable MCH conversions were observed over a temperature range of 190–250 °C. The prominent MCH conversion at low temperatures indicated a close relationship between the catalyst layers of the Z zeolite membrane configuration.

[0173] In the above Fig. 8, in order to determine the effect of the Z zeolite membrane on the membrane reactor performance, a comparison with the G zeolite membrane reactor (impermeable treatment in MR configuration) was performed, and various WHSVs (7.7, 17, 26, 35 mg·g) were obtained in the Z zeolite membrane. -1 ·min -1 ), MCH dehydrogenation reaction at reaction temperatures (190, 205, 220, 235, 250, 275, 300 °C) and feed-side total pressures (1, 2, 3 bar) were compared.

[0174] (a1) and (a2) show the G zeolite membrane reactor at 220 °C, and it was found that the MCH conversion rate increased as the WHSV decreased. In particular, when the WHSV was 7.7 mg·g -1 ·min -1 At 1 bar, the MCH conversion differed only by about 3% from the calculated equilibrium MCH conversion, indicating that equilibrium was reached. In contrast, in the Z zeolite membrane, the decrease in WHSV led to an increase in MCH conversion beyond the equilibrium curve due to efficient H2 removal. Furthermore, for both Z and G, the MCH conversion for the endothermic reaction increased as the reaction temperature increased (from 190 to 250 °C) as expected at 1 bar.

[0175] In particular, the MCH conversion in the G-based packed bed reactor followed the equilibrium curve at each reaction temperature, indicating that it had sufficient residence time to reach equilibrium. Notably, the MCH conversion in the Z-based MR configuration exceeded the thermodynamically limited equilibrium conversion at all temperatures, achieving high MCH conversion at 250 °C (98.3% vs. 88.4% at equilibrium) and nearly complete MCH conversion at higher temperatures (99.9% and 100% at 275 and 300 °C, respectively, and 97.5% and 99.6% for the G-based MR configuration at the same temperatures, respectively).

[0176] Looking at (b1) and (c1), under the same conditions as (a1) above, the MCH dehydrogenation reaction was carried out at three different reaction temperatures of 190, 220, and 250 °C as representative temperatures, under conditions of 2 bar and 3 bar, respectively, by changing the pressure.

[0177] Referring to (a1) to (c2), in general, according to Le Chatelier's principle, an increase in the total pressure in the MCH dehydrogenation reaction will favor the reverse reaction toward the reactant side. In fact, when the total pressure on the reactor side increased from 1 to 3 bar at 250 °C, the MCH conversion in G decreased from 89.8% to 55.2%. However, in the Z zeolite membrane reactor, the increase in the total pressure on the reactor side proportionally increased the H2 molar flow rate toward the membrane side, shifting the equilibrium state toward the product side, causing the reverse reaction to be favored at high pressure. As a result, the MCH conversion in the Z zeolite membrane reactor was found to be 98.3% at 1 bar and 97.2% at 3 bar, which did not change significantly.

[0178] FIGS. 9 to 11 are graphs showing molar flow rates according to temperature and pressure of G and Z membrane reactors according to one embodiment of the present invention.

[0179] Figures 9 to 11 show the molar flow rates of H2, Tol, and MCH in the product streams of the G and Z zeolite membranes at different total pressures (1, 2, and 3 bar) and reaction temperatures (190, 220, and 250 °C). In general, the Z zeolite membrane reactor showed higher molar flow rates of H2 and Tol, and lower molar flow rates of MCH compared to the G zeolite membrane reactor.

[0180]

[0181] 4. Long-term stability test of the Z membrane reactor for the dehydrogenation reaction of MCH.

[0182] FIG. 12 is a graph showing molar flow rate according to reaction temperature of G and Z zeolite membrane reactors according to an embodiment of the present invention, FIG. 13 is a graph showing molar flow rate and Tol yield according to reaction temperature of G zeolite membrane reactor according to an embodiment of the present invention, and FIG. 14 is a graph showing H2 molar flow rate of Z zeolite membrane reactor according to an embodiment of the present invention.

[0183] Referring to Fig. 12, the existing G and Z zeolite membrane reactors performed MCH dehydrogenation reactions at 220, 250, and 300 °C. However, in order to conduct a long-term stability test, the MCH dehydrogenation reactions of the G and Z zeolite membrane reactors were performed at higher temperatures of 300, 350, and 400 °C.

[0184] Looking at (a) of Fig. 12, as can be expected from the equilibrium curve of the endothermic reaction (a1) of Fig. 8, the Tol yield reached 99.6% (almost 100%) at a relatively high temperature of 300 °C in the G membrane reactor. However, as the temperature increased above 350 °C, undesired Tol demethylation occurred, producing benzene and methane, resulting in a decrease in the Tol yield.

[0185] Referring to Figure 13, further increasing the reaction temperature to 450 °C activated undesirable demethylation and significantly generated corresponding byproducts. Specifically, the Tol yield decreased from approximately 99.5% to 51.9% at 300 °C and 450 °C, respectively. Therefore, for practical applications, a lower operating temperature, such as the Z zeolite membrane reactor shown in Figure 12, is desirable.

[0186] As shown in Fig. 12(b), the catalytic MCH dehydrogenation activity generally decreases at low temperatures, and a relatively low Tol yield (78%) was obtained during the long-term stability test at 220 °C. However, at moderate temperatures (250 and 300 °C), the Tol yield reached approximately 100% and was maintained throughout the test period without catalyst deactivation or side reactions.

[0187] Referring to Fig. 14, the H2molar flow rate was obtained by combining the H2molar flow rates of the permeate side (half-filled symbols) and the retentate side (empty symbols) of the Z zeolite membrane reactor. The H2molar flow rates of the permeate side and the retentate side were almost constant, indicating a stable separation ability of Z for up to 7 days. That is, at normal temperature (250 °C), the Z zeolite membrane reactor avoided side reactions during MCH dehydrogenation and exhibited good reaction performance and durability.

[0188]

[0189] 5. Effects on membrane reactor performance in vacuum mode

[0190] FIG. 15 is a graph of the MCH dehydrogenation reaction performance of the G and Z zeolite membrane reactors in vacuum mode according to one embodiment of the present invention, and FIG. 16 is a graph of a time-on-stream function for the MCH dehydrogenation reaction of the Z zeolite membrane reactor according to temperature change in vacuum mode according to one embodiment of the present invention.

[0191] Referring to Fig. 15, permeability, molar flux, H2 / Tol SF, and H2 purity were considered to investigate the H2 separation performance in the MCH dehydrogenation reaction in vacuum mode of G and Z. As a result, all characteristics were significantly improved in vacuum mode compared to the sweep mode shown in Fig. 4. In particular, the maximum H2 / Tol separation factor (SF) in vacuum mode at 190 °C was very high at approximately 1035, and the corresponding H2 purity was approximately 99.95%.

[0192] Looking at (a1) to (b2), it was found that the dehydrogenation reaction performance of the Z zeolite membrane reactor in vacuum mode more effectively led to a shift in equilibrium toward the product side than in sweep mode.

[0193] Referring to Fig. 16, the molar flow rates of H2, Tol, and MCH on the product side at 190, 220, and 250 °C are shown. It was observed that stable molar flow rates of all reactants (MCH) and products (H2 and Tol) were maintained for up to 190 minutes of reaction, demonstrating the robustness of the membrane reactor configuration.

[0194] Those skilled in the art will appreciate that the present invention can be implemented in other specific forms without altering its technical spirit or essential characteristics. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims below rather than the detailed description above, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included within the scope of the present invention.

[0195] (Explanation of symbols)

[0196] 1: Zeolite membrane reactor for dehydrogenation of liquid organic hydrogen carrier

[0197] 100: Reactor,

[0198] 110: Reactant inlet

[0199] 120: Product discharge section

[0200] 130: Gas inlet

[0201] 140: Gas discharge section

[0202] 150: Zeolite membrane

[0203] 160: Catalyst

Claims

1. In a zeolite membrane reactor for dehydrogenation of a liquid organic hydrogen carrier, A reactor in which a dehydrogenation reaction is performed; A reactant inlet provided on one side of the above reactor for introducing reactants into the interior; A product discharge unit provided on the other side of the reactor to discharge at least a portion of the product of the dehydrogenation reaction to the outside; A gas inlet provided adjacent to the product discharge portion for introducing sweep gas into the reactor; and a gas discharge port provided adjacent to the reactant inlet port for discharging at least another portion of the product of the dehydrogenation reaction to the outside of the reactor; A zeolite separation membrane reactor for dehydrogenation of a liquid organic hydrogen carrier, wherein a zeolite separation membrane and a catalyst are provided within the above reactor.

2. In paragraph 1, The above zeolite separation membrane is, A tubular support having an internal space; and A zeolite separation membrane reactor for dehydrogenation of a liquid organic hydrogen carrier, comprising a zeolite provided on the inside and the inside surface of the support and including at least one structure of a CHA structure and a DDR structure.

3. In paragraph 1, The cross-section of the above zeolite membrane is A first layer comprising a CHA structure, a DDR structure, and a support; A second layer provided on the surface of the support and including a CHA structure and a DDR structure; and A third layer provided on the second layer and including a DDR structure; A zeolite membrane reactor for dehydrogenation of a liquid organic hydrogen carrier, wherein the average thickness of the first to third layers is 0.1 ㎛ to 5.0 ㎛.

4. In paragraph 3, A zeolite separation membrane reactor for dehydrogenation of a liquid organic hydrogen carrier, wherein the CHA structure is included in an amount of 5 to 50 parts by weight for 100 parts by weight of the entire zeolite structure of the first, second, and third layers.

5. In paragraph 3, The average thickness of the first layer is 0.1 ㎛ to 1.0 ㎛, The average thickness of the second layer is 0.1 ㎛ to 5.0 ㎛, A zeolite membrane reactor for dehydrogenation of a liquid organic hydrogen carrier, wherein the average thickness of the third layer is 0.1 ㎛ to 5.0 ㎛.

6. In paragraph 1, The above catalyst comprises a Pt / C catalyst diluted with quartz filled in the internal space of the support provided in the zeolite separation membrane, A zeolite membrane reactor for dehydrogenation of a liquid organic hydrogen carrier, comprising the above Pt / C catalyst: quartz = 1:1 to 10 in a weight ratio.

7. In paragraph 6, The size of the above quartz is 50 ㎛ to 600 ㎛, A zeolite membrane reactor for dehydrogenation of a liquid organic hydrogen carrier, comprising a Pt / C catalyst having a size of 50 ㎛ to 500 ㎛.

8. In paragraph 2, The above support is, A zeolite membrane reactor for dehydrogenation of a liquid organic hydrogen carrier comprising at least one of α-alumina, γ-alumina, polypropylene, polyethylene, polytetrafluoroethylene, polysulfone, polyimide, silica, glass, mullite, zirconia, titania, yttria, ceria, vanadia, silicon, stainless steel, carbon, calcium oxide, and phosphorus oxide.

9. In paragraph 1, The above reactor produces toluene and hydrogen (H2) through a dehydrogenation reaction of methylcyclohexane (MCH), A zeolite membrane reactor for dehydrogenation of a liquid organic hydrogen carrier having an MCH conversion rate (%) of 30% to 99% at 190 °C to 275 °C.

10. In paragraph 1, The above reactants are at least one of methylcyclohexane, methylcyclopentane, cyclohexane, decalin, perhydro-dibenzyltoluene, dodecahydro-N-ethylcarbazole, 1-methylperhydro indole, 2-methylperhydro indole, 1,2-perhydrodimethyl indole, perhydro-phenazine, and perhydro-2-(n-methylbenzyl pyridine). A zeolite membrane reactor for dehydrogenation of a liquid organic hydrogen carrier, wherein the product comprises at least one of hydrogen (H2), toluene, benzene, naphthalene, dibenzyl toluene, benzyl toluene, N-ethyl carbazole, 1-methylperhydro indole, 2-methylperhydro indole, 1,2-perhydrodimethyl indole, phenazine, and 2-n-methylbenzyl pyridine.

11. In paragraph 1, In the above reactor, cyclic hydrocarbons are produced into hydrogen (H2) and aromatic hydrocarbons through dehydrogenation reaction, The cyclic hydrocarbon and carrier gas are introduced into the above reactant inlet, The cyclic hydrocarbon, the aromatic hydrocarbon, hydrogen (H2) and carrier gas are discharged through the product discharge section, The above gas inlet section is where sweep gas is introduced, The above gas discharge unit is a zeolite separation membrane reactor for dehydrogenation of a liquid organic hydrogen carrier, which includes the sweep gas and hydrogen (H2) discharged therefrom.

12. In paragraph 11, The carrier gas is at least one of argon (Ar), nitrogen (N2), and helium (He), A zeolite membrane reactor for dehydrogenation of a liquid organic hydrogen carrier, wherein the above sweep gas comprises at least one of argon (Ar), nitrogen (N2), and helium (He).

13. In paragraph 11, The inflow rate of the above cyclic hydrocarbon is 0.001 mL·min -1 10 mL·min -1 And, The inflow rate of the carrier gas is 1 mL·min -1 Up to 1000 mL·min -1 And, The inflow rate of the above sweep gas is 1 mL·min -1 Up to 1000 mL·min -1 A zeolite membrane reactor for dehydrogenation of a liquid organic hydrogen carrier comprising:

14. In paragraph 3, The above CHA structure is manufactured using a CHA precursor solution, The above CHA precursor solution contains a first organic structure derivative, SiO2, H2O, a sodium compound, and an aluminum compound, The above first organic structure derivative, SiO2, H2O, sodium compound, and aluminum compound are each in a molar ratio of 0.1 to 1000: 100: 100 to 50000: 0 to 500: 0 to 100, The first organic structure derivative is TMAdaOH (N,N,N-trimethyl adamantylammoniumhydroxide), TMAdaBr (N,N,Ntrimethyl adamantylammoniumbromide), TMAdaF (N,N,N-trimethyl adamantylammoniumfluoride), TMAdaCl (N,N,N-trimethyl adamantylammoniumchloride), TMAdaI (N,N,N-trimethyl adamantylammonium iodide), TEAOH (tetraethylammonium hydroxide), TEABr (tetraethylammonium bromide), TEAF (tetraethylammonium fluoride), TEACl (tetraethylammonium chloride), TEAI (tetraethylammoniumiodide), dipropylamine, Cyclohexylamine, TMAOH (Tetramethylammonium hydroxide), BTMAOH (Benzyltrimethylammoniumhydroxide), BTMACl (Benzyltrimethylammoniumchloride), Choline Chloride, NH4F (Ammonium Fluoride), DMCHABr (Dimethylethylcyclohexylammonium bromide), M3CyNOH (Trimethylcyclohexylammoniumhydroxide), Cu-TEPA (Cu 2+ A zeolite membrane reactor for dehydrogenation of a liquid organic hydrogen carrier comprising at least one of tetraethylenepentamine (coordinated with tetraethylenepentamine) and TMAibOH (Trimethylisobutylammoniumhydroxide).

15. In paragraph 14, A CHA structure is manufactured by a hydrothermal synthesis method using the above CHA precursor solution, Including a first growth step for forming seed particles including the above CHA structure, A zeolite membrane reactor for dehydrogenation of a liquid organic hydrogen carrier, wherein the above hydrothermal synthesis method is performed for 6 to 400 hours and at 100 °C to 250 °C.

16. In paragraph 15, The above first growth stage is, Using the above CHA precursor solution, seed particles containing a CHA structure are synthesized by a hydrothermal synthesis method, The above seed particles are dispersed in a solvent to prepare a suspension, Immersing a support in the above suspension and coating the seed particles on the surface of the support, Drying the support coated with the seed particles, A zeolite membrane reactor for dehydrogenation of a liquid organic hydrogen carrier, comprising heat-treating the support coated with the seed particles at 300 °C to 550 °C for 1 hour to 24 hours after drying is completed.

17. In paragraph 3, The above DDR structure is manufactured using a DDR precursor solution, The above DDR precursor solution contains SiO2, a second organic structure derivative, H2O, a sodium compound, and an aluminum compound, The above SiO2, second organic structure derivative, H2O, sodium compound, and aluminum compound are each in a molar ratio of 100:1~1000:10~100000:0~500:0~100, A zeolite membrane reactor for dehydrogenation of a liquid organic hydrogen carrier, wherein the second organic structure derivative comprises at least one of methyltropinium iodide, methyltropinium bromide, methyltropinium fluoride, methyltropinium chloride, methyltropinium hydroxide, quinuclidinium, TEAOH (tetraethylammonium hydroxide), TEABr (tetraethylammonium bromide), TEAF (tetraethylammonium fluoride), TEACl (tetraethylammonium chloride), TEAI (tetraethylammonium iodide), ethylenediamine, and adamantylamine.

18. In paragraph 15 or 17, A DDR structure is manufactured by covering the seed particle using the above DDR precursor solution using a hydrothermal synthesis method, Including a second growth stage that forms a layered structure including the above DDR structure, A zeolite membrane reactor for dehydrogenation of a liquid organic hydrogen carrier, wherein the above hydrothermal synthesis method is performed for 6 to 400 hours and at 100 °C to 250 °C.

19. In paragraph 18, After the above secondary growth stage, a heat treatment stage is further included, A zeolite membrane reactor for dehydrogenation of a liquid organic hydrogen carrier, wherein the heat treatment step is performed at a temperature range of 100 °C to 300 °C in an ozone atmosphere.

20. In paragraph 2, The average pore diameter of the above support is 0.7 μm to 0.9 μm, The zeolite membrane has a pore size of 0.36 nm to 0.44 nm, A zeolite membrane reactor for dehydrogenation of a liquid organic hydrogen carrier, comprising 1 wt% or less of adamantylamine within the pores of the membrane.

21. In paragraph 2, The above zeolite membrane is 1x10 -9 1x10 -5 mol·m -2 ·s -1 ·Pa -1 A zeolite membrane reactor for dehydrogenation of a liquid organic hydrogen carrier having a hydrogen permeability of .

22. In paragraph 14 or paragraph 17, The above CHA precursor solution and DDR precursor solution each contain Si and Al, The above CHA structure has a molar ratio standard of Si:Al of 100:0~10, The above DDR structure is a zeolite separation membrane reactor for dehydrogenation of a liquid organic hydrogen carrier, which includes a molar ratio standard value of Si:Al of 100:0 to 10.

23. In paragraph 1, A zeolite membrane reactor for dehydrogenation of a liquid organic hydrogen carrier, wherein the purity of hydrogen discharged from the reactor is 99% or higher and the separation coefficient is 100 or higher.

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