A method for preparing HZSM-5 catalyst using montmorillonite, its application and application methods

Abstract

This invention discloses a method for preparing HZSM-5 catalyst using montmorillonite. Sodium-based montmorillonite is used as a raw material. The sodium-based montmorillonite undergoes sub-lava activation treatment. The activated montmorillonite, along with tetraethyl orthosilicate, tetrapropylammonium hydroxide, and water, is then used to prepare the HZSM-5 catalyst via a hydrothermal and ammonia exchange method. This invention also discloses an application of the montmorillonite-based HZSM-5 catalyst and its application method. The HZSM-5 catalyst is physically mixed with commercially available CuO / ZnO / Al2O3 to obtain a montmorillonite-based HZSM-5 bifunctional catalyst. This catalyst was used in the dimethyl ether steam reforming reaction to produce hydrogen. The initial dimethyl ether conversion rate was 100%, and the hydrogen yield was 91%, with no significant decrease after 12 hours of reaction. This invention features low preparation cost, high catalytic efficiency, and good stability.

Description

Technical Field

[0001] This invention relates to the field of catalyst technology, and more specifically, to a method for preparing HZSM-5 catalyst using montmorillonite and its application. Background Technology

[0002] With the energy crisis and environmental problems becoming increasingly severe, hydrogen energy is attracting more and more attention due to its advantages such as being environmentally friendly, having a high calorific value, being non-toxic and harmless, and being renewable. However, because hydrogen has a low density, is difficult to compress and liquefy, and is flammable and explosive, its transportation and storage are extremely inconvenient, making large-scale application difficult.

[0003] While research on pure hydrogen storage has yet to yield significant breakthroughs, using "hydrogen carriers" as the primary chemical method for hydrogen storage is a suitable approach. This involves first converting hydrogen into a substance that is easy to store and transport, and then releasing it simply and efficiently where needed. Dimethyl ether (DME) meets the requirements of a "hydrogen carrier": it exists as a liquid at room temperature and low pressure, is chemically stable, has no carcinogenic, mutagenic, or teratogenic effects, and is easily degraded in the troposphere, making it more environmentally friendly and compliant with environmental protection requirements. Furthermore, its ease of liquefaction allows hydrogen to be transported and stored like liquefied petroleum gas, and its readily available source makes DME a relatively ideal clean hydrogen carrier.

[0004] Hydrogen release from distilled metallurgical processes (DMEs) can be achieved through partial oxidative reforming, autothermal reforming, and steam reforming. Among these, steam reforming offers advantages such as low reaction temperature, high selectivity, easy product separation, simple process, and good economic efficiency, making it suitable for most hydrogen needs.

[0005] Typically, dimethyl ether (DME) steam reforming for hydrogen production (SRD) involves two consecutive steps. The first step involves the hydrolysis of DME on a solid acid catalyst (alumina, molecular sieves, etc.) to produce methanol (CH3OCH3 + H2O → 2CH3OH). The second step involves the steam reforming of methanol on a metal catalyst (noble metal, Cu-based, Zn-based catalysts, etc.) to produce CO2 and H2 (CH3OH + H2O → CO2 + 3H2). Since the two reactions require different catalytic active sites, the DME steam reforming catalyst must contain both active sites, making it a bifunctional catalyst. Furthermore, current research indicates that DME hydrolysis is likely the rate-determining step in SRD. Therefore, increasing the DME hydrolysis rate is crucial for accelerating the entire reaction, making the selection of the solid acid catalyst particularly important.

[0006] HZSM-5 exhibits good hydrothermal stability, and when used as a solid acid catalyst, DME hydrolysis shows good results at relatively low temperatures (<300℃). HZSM-5 is typically synthesized from chemicals such as sodium silicate and sodium aluminate, which are mainly derived from natural silicon and aluminum-containing minerals. The production of these chemicals involves significant energy consumption and environmental pollution, thereby increasing the cost of HZSM-5. Summary of the Invention

[0007] The purpose of this invention is to design and develop a method for synthesizing HZSM-5 catalyst using montmorillonite. By activating montmorillonite and adjusting the SiO2 / Al2O3 ratio, the acidity of the prepared HZSM-5 catalyst can be controlled, thereby improving its catalytic performance.

[0008] This invention also designed and developed an application and method for synthesizing HZSM-5 catalyst using montmorillonite. By physically mixing HZSM-5 catalyst with CuO / ZnO / Al2O3 catalyst, the synergistic catalytic reforming hydrogen production performance of the bifunctional catalyst is optimized, and the catalytic efficiency of montmorillonite-based HZSM-5 catalyst is significantly improved.

[0009] The technical solution provided by this invention is as follows:

[0010] A method for preparing HZSM-5 catalyst using montmorillonite, comprising:

[0011] Step 1: Mix sodium-based montmorillonite, sodium hydroxide, and water in a mass ratio of 1:1:4 and then calcine to obtain activated montmorillonite;

[0012] Step 2: Mix the activated montmorillonite, tetraethyl orthosilicate, tetrapropylammonium hydroxide and water, and then perform hydrothermal crystallization. After drying and calcination, obtain the ZSM-5 catalyst.

[0013] The molar ratio of SiO2:Al2O3:TPAOH:H2O in the mixture of activated montmorillonite, tetraethyl orthosilicate, tetrapropylammonium hydroxide and water is 20:1:6:1600, 30:1:9:2400, 40:1:12:3200 or 50:1:15:4000.

[0014] Step 3: The ZSM-5 catalyst is subjected to an ammonium exchange reaction with a 1 mol / L ammonium chloride solution, followed by centrifugation, washing, drying, and calcination to obtain the HZSM-5 catalyst;

[0015] Each 3g ZSM-5 catalyst is mixed with 100mL NH4Cl solution.

[0016] Preferably, the roasting in step one includes:

[0017] The mixture was placed in a muffle furnace and heated to 250°C at a rate of 5°C / min for 2 hours for activation.

[0018] Preferably, the mixture in step two needs to be stirred for 12 hours.

[0019] Preferably, the hydrothermal method specifically comprises:

[0020] The mixture was placed in a hydrothermal reactor and crystallized at 170°C for 24 hours, then centrifuged, washed, and dried.

[0021] Preferably, the roasting in step two includes:

[0022] The centrifuged, washed, and dried material was placed in a muffle furnace and heated to 550°C at a heating rate of 5°C / min. It was then calcined in air for 6 hours and allowed to cool naturally to room temperature.

[0023] Preferably, step three further includes:

[0024] The ZSM-5 catalyst was mixed with a 1 mol / L ammonium chloride solution and stirred in a water bath at 85°C for 4 hours.

[0025] Preferably, the roasting in step three includes:

[0026] After centrifugation, the mixture was dried and placed in a muffle furnace and heated to 550°C at a heating rate of 5°C / min. It was then calcined in air for 6 hours and allowed to cool naturally to room temperature.

[0027] An application of HZSM-5 catalyst synthesized using montmorillonite, wherein the HZSM-5 catalyst prepared using the aforementioned method for synthesizing HZSM-5 catalyst using montmorillonite is used in the dimethyl ether steam reforming hydrogen production reaction.

[0028] An application method for synthesizing HZSM-5 catalyst using montmorillonite, wherein the HZSM-5 catalyst prepared using the aforementioned method for synthesizing HZSM-5 catalyst using montmorillonite comprises the following steps:

[0029] Step 1: Mix the HZSM-5 catalyst with CuO / ZnO / Al2O3 catalyst at a mass ratio of 1:1, then compress and granulate the mixture to obtain a montmorillonite-based HZSM-5 bifunctional catalyst.

[0030] Step 2: The montmorillonite-based HZSM-5 bifunctional catalyst is loaded into a fixed-bed reactor. First, a H2 / N2 mixture with a H2 content of 10% is used for reduction at 285°C for 1 hour. Then, a mixture of dimethyl ether, water vapor and nitrogen is introduced into the reaction tube to produce hydrogen.

[0031] The molar ratio of dimethyl ether, water vapor, and nitrogen in the mixed gas is 1:4:5, and the reaction temperature is 290℃-400℃.

[0032] Preferably, the granules obtained in step 1 need to pass through a 40-60 mesh sieve.

[0033] The beneficial effects of this invention are as follows:

[0034] (1) The present invention designs and develops a method for preparing HZSM-5 catalyst using montmorillonite. The montmorillonite-based HZSM-5 catalyst is prepared by activating sodium-based montmorillonite, hydrothermating and ammonia exchange treatment, so as to destroy the silicon-oxygen tetrahedron and aluminum-oxygen octahedron structure in montmorillonite. The acidity of HZSM-5 can be modulated by adjusting SiO2 / Al2O3. The HZSM-5 catalyst synthesized by this method catalyzes the hydrolysis of dimethyl ether to methanol. The operation is simple, inexpensive and readily available.

[0035] (2) The application and application method of the HZSM-5 catalyst synthesized by montmorillonite designed and developed in this invention: The HZSM-5 catalyst is physically mixed with CuO / ZnO / Al2O3 catalyst to prepare a bifunctional dimethyl ether steam reforming hydrogen production catalyst, which optimizes the synergistic catalytic reforming hydrogen production performance of the bifunctional catalyst, greatly improves the catalytic efficiency of the montmorillonite-based HZSM-5+CuO / ZnO / Al2O3 bifunctional catalyst, and realizes the physical integration of solid acid catalyst and reforming catalyst. Detailed Implementation

[0036] The present invention will now be described in further detail so that those skilled in the art can implement it based on the description.

[0037] The present invention provides a method for preparing HZSM-5 catalyst using montmorillonite, comprising the following steps:

[0038] Step 1: Mix sodium-based montmorillonite, sodium hydroxide and water in a mass ratio of 1:1:4 and place them in a muffle furnace. Heat the mixture to 250°C at a rate of 5°C / min and calcine for 2 hours to obtain activated montmorillonite (SMS-MMT).

[0039] Step 2: After mixing SMS-MMT, tetraethyl orthosilicate (TEOS), tetrapropylammonium hydroxide (TPAOH) and water, stir for 12 hours to carry out hydrothermal reaction. After stirring, place the mixture in a hydrothermal reactor and crystallize at 170°C for 24 hours. Centrifuge, wash and dry the crystallized sample. Place the dried sample in a muffle furnace and heat it to 550°C at a heating rate of 5°C / min. Calcinate in air atmosphere for 6 hours and allow to cool naturally to room temperature to obtain ZSM-5 catalyst.

[0040] The molar ratio of SiO2:Al2O3:TPAOH:H2O in the mixture of SMS-MMT, TEOS, TPAOH and water is 20:1:6:1600, 30:1:9:2400, 40:1:12:3200 or 50:1:15:4000.

[0041] Step 3: Mix the ZSM-5 catalyst with a 1 mol / L ammonium chloride solution, stir in an 85°C water bath for 4 hours, centrifuge, wash and dry, then place in a muffle furnace and heat to 550°C at a heating rate of 5°C / min, calcine in air atmosphere for 6 hours, and naturally cool to room temperature to obtain the HZSM-5 catalyst.

[0042] Each 3g ZSM-5 catalyst is mixed with 100mL NH4Cl solution.

[0043] This invention also provides an application and method for synthesizing HZSM-5 catalyst using montmorillonite. Dimethyl ether steam reforming to produce hydrogen is a series of reactions, and the overall reaction equation is (eq(1)). The first step in dimethyl ether steam reforming to produce hydrogen is the hydrolysis of dimethyl ether to produce methanol (eq(2)), which occurs on a solid acid catalyst. Then, the methanol produced reacts with water to produce hydrogen and carbon dioxide (eq(3)). At the same time as the dimethyl ether steam reforming reaction occurs, side reactions also occur (eq(4)-(8)).

[0044] DME steam reforming: CH3OCH3+3H2O→6H2+2CO2 (1)

[0045] DME hydrolysis: CH3OCH3+H2O→2CH3OH (2)

[0046] MeOH steam reforming: CH3OH+H2O→3H2+CO2 (3)

[0047] r-WGS: CO2 + H2 → H2O + CO (4)

[0048] DME decomposition: CH3OCH3→CH4+H2+CO (5)

[0049] Direct CO2 formation: CH3OCH3+2H2O→CH4+CO 2+ 2H2 (6)

[0050] MeOH decomposition: CH3OH→CO+2H2 (7)

[0051] Methanation: CO+3H2→CH4+H2O (8)

[0052] The application method described in this invention specifically includes the following steps:

[0053] Step 1: Mix the HZSM-5 catalyst with a commercial CuO / ZnO / Al2O3 catalyst at a mass ratio of 1:1, compress and granulate the mixture, and pass it through a 40-60 mesh sieve to obtain a montmorillonite-based HZSM-5 bifunctional catalyst.

[0054] The commercially available CuO / ZnO / Al2O3 catalyst is a purchased finished CuO / ZnO / Al2O3 catalyst;

[0055] Step 2: The montmorillonite-based HZSM-5 bifunctional catalyst is loaded into a fixed-bed reactor. First, it is reduced at 285°C for 1 hour with a H2 / N2 mixture containing 10% H2. Then, a mixture of dimethyl ether, water vapor, and nitrogen is introduced into the reaction tube to produce hydrogen.

[0056] The molar ratio of dimethyl ether, water vapor, and nitrogen in the mixed gas is 1:4:5, and the reaction temperature is 290℃-400℃.

[0057] Example 1

[0058] Step 1: Mix 5g sodium montmorillonite, 5g NaOH and 20g H2O evenly and place them in a muffle furnace. Heat the mixture to 250℃ at a rate of 5℃ / min and calcine for 2 hours to obtain activated montmorillonite (SMS-MMT).

[0059] Step 2: Prepare ZSM-5 catalyst using a hydrothermal method with a SiO2 / Al2O3 ratio of 20:

[0060] 1g SMS-MMT, 8.40g TEOS, 12.20g TPAOH and 72mL H2O were added to a beaker and stirred at room temperature for 12h. The stirred sample was placed in a hydrothermal reactor and crystallized at 170℃ for 24h. The crystallized sample was centrifuged and washed, and then dried in a 100℃ oven to constant weight. It was then ground into powder and placed in a muffle furnace and heated to 550℃ at a heating rate of 5℃ / min. It was calcined in air atmosphere for 6h and then naturally cooled to room temperature. The ZSM-5 catalyst was obtained.

[0061] Step 3: Place 3g of ZSM-5 catalyst into a round-bottom flask, add 100mL of 1mol / L NH4Cl solution, stir at 85℃ for 4h, centrifuge and wash until neutral, then place in a 100℃ oven to dry to constant weight, take out and grind into powder, place in a muffle furnace and heat to 550℃ at a heating rate of 5℃ / min, calcine in air atmosphere for 6h, cool naturally to room temperature, and take out to obtain HZSM-5 catalyst;

[0062] The HZSM-5 catalyst was then physically mixed with a commercial CuO / ZnO / Al2O3 catalyst at a mass ratio of 1:1. After mixing, the mixture was pressed into tablets, granulated, and passed through a 40-60 mesh sieve to prepare a montmorillonite-based HZSM-5 bifunctional catalyst.

[0063] Example 2

[0064] Step 1: Mix 5g sodium montmorillonite, 5g NaOH and 20g H2O evenly and place them in a muffle furnace. Heat the mixture to 250℃ at a rate of 5℃ / min and calcine for 2 hours to obtain activated montmorillonite (SMS-MMT).

[0065] Step 2: Prepare ZSM-5 catalyst using a hydrothermal method with a SiO2 / Al2O3 ratio of 30:

[0066] 1g SMS-MMT, 13.60g TEOS, 18.30g TPAOH and 108mL H2O were added to a beaker and stirred at room temperature for 12h. The stirred sample was placed in a hydrothermal reactor and crystallized at 170℃ for 24h. The crystallized sample was centrifuged and washed, and then dried in a 100℃ oven to constant weight. It was then ground into powder and placed in a muffle furnace and heated to 550℃ at a heating rate of 5℃ / min. It was calcined in air atmosphere for 6h and then naturally cooled to room temperature. The ZSM-5 catalyst was obtained.

[0067] Step 3: Place 3g of ZSM-5 catalyst into a round-bottom flask, add 100mL of 1mol / L NH4Cl solution, stir at 85℃ for 4h, centrifuge and wash until neutral, then place in a 100℃ oven to dry to constant weight, take out and grind into powder, place in a muffle furnace and heat to 550℃ at a heating rate of 5℃ / min, calcine in air atmosphere for 6h, cool naturally to room temperature, and take out to obtain HZSM-5 catalyst;

[0068] The HZSM-5 catalyst was then physically mixed with a commercial CuO / ZnO / Al2O3 catalyst at a mass ratio of 1:1. After mixing, the mixture was pressed into tablets, granulated, and passed through a 40-60 mesh sieve to prepare a montmorillonite-based HZSM-5 bifunctional catalyst.

[0069] Example 3

[0070] Step 1: Mix 5g sodium montmorillonite, 5g NaOH and 20g H2O evenly and place them in a muffle furnace. Heat the mixture to 250℃ at a rate of 5℃ / min and calcine for 2 hours to obtain activated montmorillonite (SMS-MMT).

[0071] Step 2: Prepare ZSM-5 catalyst using a hydrothermal method with a SiO2 / Al2O3 ratio of 40:

[0072] 1g SMS-MMT, 18.80g TEOS, 24.40g TPAOH and 144mL H2O were added to a beaker and stirred at room temperature for 12h. The stirred sample was placed in a hydrothermal reactor and crystallized at 170℃ for 24h. The crystallized sample was centrifuged and washed, and then dried in a 100℃ oven to constant weight. It was then ground into powder and placed in a muffle furnace and heated to 550℃ at a heating rate of 5℃ / min. It was calcined in air atmosphere for 6h and then naturally cooled to room temperature. The ZSM-5 catalyst was obtained.

[0073] Step 3: Place 3g of ZSM-5 catalyst into a round-bottom flask, add 100mL of 1mol / L NH4Cl solution, stir at 85℃ for 4h, centrifuge and wash until neutral, then place in a 100℃ oven to dry to constant weight, take out and grind into powder, place in a muffle furnace and heat to 550℃ at a heating rate of 5℃ / min, calcine in air atmosphere for 6h, cool naturally to room temperature, and take out to obtain HZSM-5 catalyst;

[0074] The HZSM-5 catalyst was then physically mixed with a commercial CuO / ZnO / Al2O3 catalyst at a mass ratio of 1:1. After mixing, the mixture was pressed into tablets, granulated, and passed through a 40-60 mesh sieve to prepare a montmorillonite-based HZSM-5 bifunctional catalyst.

[0075] Example 4

[0076] Step 1: Mix 5g sodium montmorillonite, 5g NaOH and 20g H2O evenly and place them in a muffle furnace. Heat the mixture to 250℃ at a rate of 5℃ / min and calcine for 2 hours to obtain activated montmorillonite (SMS-MMT).

[0077] Step 2: Prepare ZSM-5 catalyst using a hydrothermal method with a SiO2 / Al2O3 ratio of 50.

[0078] 1g SMS-MMT, 24.00g TEOS, 30.50g TPAOH and 180mL H2O were added to a beaker and stirred at room temperature for 12h. The stirred sample was placed in a hydrothermal reactor and crystallized at 170℃ for 24h. The crystallized sample was centrifuged and washed, and then dried in a 100℃ oven to constant weight. It was then ground into powder and placed in a muffle furnace and heated to 550℃ at a heating rate of 5℃ / min. It was calcined in air atmosphere for 6h and then naturally cooled to room temperature. The ZSM-5 catalyst was obtained.

[0079] Step 3: Place 3g of ZSM-5 catalyst into a round-bottom flask, add 100mL of 1mol / L NH4Cl solution, stir at 85℃ for 4h, centrifuge and wash until neutral, then place in a 100℃ oven to dry to constant weight, take out and grind into powder, place in a muffle furnace and heat to 550℃ at a heating rate of 5℃ / min, calcine in air atmosphere for 6h, cool naturally to room temperature, and take out to obtain HZSM-5 catalyst;

[0080] The HZSM-5 catalyst was then physically mixed with a commercial CuO / ZnO / Al2O3 catalyst at a mass ratio of 1:1. After mixing, the mixture was pressed into tablets, granulated, and passed through a 40-60 mesh sieve to prepare a montmorillonite-based HZSM-5 bifunctional catalyst.

[0081] Comparative Example 1

[0082] Commercial HZSM-5 catalyst and commercial CuO / ZnO / Al2O3 catalyst were physically mixed at a mass ratio of 1:1. After mixing, the mixture was pressed into tablets, granulated, and passed through a 40-60 mesh sieve to prepare a commercial HZSM-5 bifunctional catalyst.

[0083] When the SiO2 / Al2O3 ratio is less than 20, it is impossible to synthesize montmorillonite-based HZSM-5 bifunctional catalysts.

[0084] Comparative Example 2

[0085] Step 1: Mix 5g sodium montmorillonite, 5g NaOH and 20g H2O evenly and place them in a muffle furnace. Heat the mixture to 250℃ at a rate of 5℃ / min and calcine for 2 hours to obtain activated montmorillonite (SMS-MMT).

[0086] Step 2: Prepare ZSM-5 catalyst using a hydrothermal method with a SiO2 / Al2O3 ratio of 80:

[0087] 1g SMS-MMT, 39.60g TEOS, 46.46g TPAOH and 288mL H2O were added to a beaker and stirred at room temperature for 12h. The stirred sample was placed in a hydrothermal reactor and crystallized at 170℃ for 24h. The crystallized sample was centrifuged and washed, and then dried in a 100℃ oven to constant weight. It was then ground into powder and placed in a muffle furnace and heated to 550℃ at a heating rate of 5℃ / min. It was calcined in air atmosphere for 6h and then naturally cooled to room temperature. The ZSM-5 catalyst was obtained.

[0088] Step 3: Place 3g of ZSM-5 catalyst into a round-bottom flask, add 100mL of 1mol / L NH4Cl solution, stir at 85℃ for 4h, centrifuge and wash until neutral, then place in a 100℃ oven to dry to constant weight, take out and grind into powder, place in a muffle furnace and heat to 550℃ at a heating rate of 5℃ / min, calcine in air atmosphere for 6h, cool naturally to room temperature, and take out to obtain HZSM-5 catalyst;

[0089] The HZSM-5 catalyst was then physically mixed with a commercial CuO / ZnO / Al2O3 catalyst at a mass ratio of 1:1. After mixing, the mixture was pressed into tablets, granulated, and passed through a 40-60 mesh sieve to prepare a montmorillonite-based HZSM-5 bifunctional catalyst.

[0090] Table 1 shows the specific surface area, pore volume, and pore size distribution of the montmorillonite-based HZSM-5 bifunctional catalysts in different embodiments and comparative examples:

[0091] Table 1. Structural characteristics of the products from Examples 1-4

[0092]

[0093]

[0094] The montmorillonite-based HZSM-5 catalysts prepared in Examples 1-4 have specific surface areas of 343-411 m². 2 / g, pore volume 0.28~0.31cm 3 / g, with an average pore size of 2.86–3.46 nm.

[0095] The montmorillonite-based HZSM-5 bifunctional catalysts prepared in Examples 1-4 and the commercially available HZSM-5 bifunctional catalysts prepared in Comparative Examples 1 and 2 were weighed out at 0.6 g each and placed in a fixed-bed reactor. A hydrogen-nitrogen mixture with a mass fraction of 10% was introduced at a flow rate of 30 mL / min. The reactor was subjected to reduction at atmospheric pressure and 285 °C for 1 hour. The hydrogen-nitrogen mixture was then stopped, and the temperature was raised to 300 °C under a nitrogen atmosphere. A mixture of DME, H2O, and N2 was introduced at a mass hourly space velocity of 5000 mL / (g·h). The reaction was carried out continuously at atmospheric pressure and 300 °C for 12 hours. The reaction products were analyzed by online gas chromatography, and the results are shown in Table 2.

[0096] Table 2 Product Results

[0097]

[0098] As can be seen, the initial dimethyl ether conversion rate of the products prepared in Examples 1-4 is above 93%, and the hydrogen yield is above 82%. Even after 12 hours of reaction, the dimethyl ether conversion rate is still above 76%, and the hydrogen yield is above 62%. Compared with the products prepared in the comparative example, the catalytic effect is significantly improved. The best catalyst prepared in this invention is the HZSM-5 catalyst with SiO2 / Al2O3 = 40, with an initial dimethyl ether conversion rate of 100% and a hydrogen yield of 94%. It is evident that the montmorillonite-based HZSM-5 bifunctional catalyst described in this invention can maintain stability while exhibiting better catalytic performance and a longer service life.

[0099] This invention relates to the application and method of synthesizing HZSM-5 catalyst using montmorillonite. The prepared catalyst is used for hydrogen production by steam reforming dimethyl ether, which improves the catalytic performance.

[0100] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and embodiments shown and described herein.

Claims

1. The use of HZSM-5 catalyst synthesized with montmorillonite in the reaction of dimethyl ether steam reforming to produce hydrogen, characterized in that, It comprises the following steps: Step 1, the HZSM-5 catalyst is mixed with CuO / ZnO / Al2O3 catalyst at a mass ratio of 1:1, then tabletting and granulation are carried out to obtain a montmorillonite-based HZSM-5 bifunctional catalyst; Step 2, the montmorillonite-based HZSM-5 bifunctional catalyst is loaded into a fixed bed reactor, first reduced at 285 DEG C for 1h with H2 / N2 mixed gas with H2 accounting for 10%, then a mixed gas of dimethyl ether, water vapor and nitrogen is introduced into the reaction tube to prepare hydrogen; The molar ratio of dimethyl ether, water vapor and nitrogen in the mixed gas is 1:4:5, and the reaction temperature is 290 DEG C-400 DEG C; The preparation method of the montmorillonite-based HZSM-5 catalyst comprises the following steps: Step one, the sodium-based montmorillonite, sodium hydroxide and water are mixed uniformly at a mass ratio of 1:1:4, then calcined to obtain activated montmorillonite; The calcination in step one comprises: The mixture is placed in a muffle furnace and heated to 250 DEG C at a rate of 5 DEG C / min, and activated for 2 hours; Step two, the activated montmorillonite, tetraethyl orthosilicate, tetrapropylammonium hydroxide and water are mixed and then subjected to hydrothermal crystallization, and the ZSM-5 catalyst is obtained after drying and calcination; The molar ratio of SiO2:Al2O3:TPAOH:H2O in the mixture of activated montmorillonite, tetraethyl orthosilicate, tetrapropylammonium hydroxide and water is 20:1:6:1600, 30:1:9:2400, 40:1:12:3200 or 50:1:15:4000; The hydrothermal method specifically comprises: The mixture is placed in a hydrothermal kettle and crystallized at 170 DEG C for 24 hours, then centrifuged, washed and dried; Step three, the ZSM-5 catalyst is subjected to ammonium exchange reaction with 1 mol / L ammonium chloride solution, then centrifuged, washed and dried, and the HZSM-5 catalyst is obtained after calcination; Wherein, 3g of ZSM-5 catalyst is mixed with 100ml of NH4Cl solution, and the ZSM-5 catalyst is mixed with 1 mol / L ammonium chloride solution and stirred in a 85 DEG C water bath for 4 hours.

2. Use of HZSM-5 catalyst synthesized with montmorillonite in the hydrogen production reaction by dimethyl ether steam reforming according to claim 1, characterized in that, The mixture in step two needs to be stirred for 12 hours.

3. Use of HZSM-5 catalyst synthesized with montmorillonite in the hydrogen production reaction by dimethyl ether steam reforming according to claim 2, characterized in that, The calcination in step two comprises: The centrifuged, washed and dried material is placed in a muffle furnace and heated to 550 DEG C at a rate of 5 DEG C / min, and calcined in air atmosphere for 6 hours, and then naturally cooled to room temperature.

4. Use of HZSM-5 catalyst synthesized with montmorillonite in the hydrogen production reaction by dimethyl ether steam reforming according to claim 3, characterized in that, The calcination in step three comprises: The centrifuged mixture is dried and then placed in a muffle furnace and heated to 550 DEG C at a rate of 5 DEG C / min, and calcined in air atmosphere for 6 hours, and then naturally cooled to room temperature.

5. Use of HZSM-5 catalyst synthesized with montmorillonite in the hydrogen production reaction by dimethyl ether steam reforming according to claim 4, characterized in that, The granules obtained by granulation in step 1 need to pass through a 40-60 mesh sieve.

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