SiSiC foamed ceramic electrically-driven reactor for hydrogen production through ammonia decomposition and preparation method of SiSiC foamed ceramic electrically-driven reactor

Abstract

The invention discloses a SiSiC foamed ceramic electrically-driven reactor for hydrogen production through ammonia decomposition and a preparation method thereof.The SiSiC foamed ceramic electrically-driven reactor comprises a quartz tube, a heating power source, a SiSiC foamed ceramic structure catalyst, carbon felts and two hollow conductive metal tubes, the SiSiC foamed ceramic structure catalyst, the carbon felts and the two hollow conductive metal tubes are arranged in the quartz tube, and the carbon felts are arranged on the upper side and the lower side of the SiSiC foamed ceramic structure catalyst; one end of the conductive metal tube is connected with the carbon felt, and the other end is externally connected with a heating power supply; the upper and lower ends of the quartz tube are respectively an air inlet and an air outlet. The SiSiC foamed ceramic matrix used in the electrically-driven reactor has high resistivity (up to 100 omega.cm) and large surface area, compared with a traditional wall heat type reactor, the electrically-driven reactor has the advantages that the temperature rise speed in a catalyst is higher, the heat transfer efficiency is higher, the efficiency of catalyzing ammonia decomposition to produce hydrogen is higher, and the service life of the reactor is prolonged. In the using process, energy consumption and CO2 emission can be effectively reduced, miniaturization and integration of the ammonia decomposition hydrogen production reactor can be achieved, and the ammonia decomposition hydrogen production reactor has wide application prospects.

Description

Technical Field

[0001] The invention belongs to the field of reactor design, and in particular relates to a SiSiC foam ceramic electric-driven reactor for producing hydrogen by decomposing ammonia and a preparation method thereof. Background Art

[0002] Ammonia, as a chemical hydrogen storage medium, has a high hydrogen content (about 17.6wt%) and energy density (3000Wh / kg), and is easy to store and transport. Traditional ammonia decomposition reactors mainly use adiabatic reactors, which are filled with molded catalyst particles. As a strong endothermic process, the use of adiabatic reactors will lead to a large temperature gradient in the radial direction of the reactor, which reduces the catalyst efficiency and increases energy consumption.

[0003] In this context, the electrically driven reactor is a new type of reactor, in which electricity directly or indirectly acts on a conductor with a certain resistance (i.e., a resistor), and heats the catalyst through the Joule heating effect of the resistor. This can not only save energy and reduce carbon emissions, but also enhance the heat transfer process within the reactor.

[0004] For the electric-driven reactor, the key lies in the selection and preparation of the resistor catalyst in the reactor. The difference in resistor material will directly affect the temperature distribution and energy efficiency of the electric-driven reactor, and will also affect the stability and catalytic effect of the catalyst. Summary of the invention

[0005] In order to solve the above problems in the prior art, the present invention provides a SiSiC foam ceramic electric-driven reactor for ammonia decomposition to produce hydrogen and a preparation method thereof. The electric-driven reactor realizes efficient catalytic decomposition of ammonia to produce hydrogen under the action of an electric field, maintaining a high energy utilization rate and ammonia-to-hydrogen conversion efficiency.

[0006] The technical solution adopted by the present invention is as follows:

[0007] The first aspect of the present invention is to provide a SiSiC foam ceramic electric-driven reactor for ammonia decomposition to produce hydrogen, comprising a quartz tube and a heating power source, and a SiSiC foam ceramic structure catalyst, a carbon felt and two hollow conductive metal tubes arranged inside the quartz tube, wherein the carbon felt is arranged on the upper and lower sides of the SiSiC foam ceramic structure catalyst, one end of the conductive metal tube is connected to the carbon felt, and the other end is externally connected to the heating power source;

[0008] The upper and lower ends of the quartz tube are respectively an air inlet and an air outlet.

[0009] The present invention is further configured such that the SiSiC foam ceramic structure catalyst is composed of a SiSiC foam ceramic matrix, an oxide carrier and a metal-based active component supported on the oxide carrier.

[0010] The present invention is further configured such that the mass composition of the SiSiC foam ceramic structure catalyst is 0.6-3wt% of metal-based active components, 10.4-12wt% of carriers, and 85-88wt% of SiSiC foam ceramic matrix.

[0011] The present invention is further configured such that the porosity of the SiSiC foam ceramic matrix is ​​50-80%.

[0012] The present invention is further configured such that the metal-based active component is selected from one or more of Ru, Ni, Fe, Co, Rh, Pt and Pb.

[0013] The present invention is further configured such that the oxide carrier is one or more of aluminum oxide, silicon oxide and titanium oxide, preferably aluminum oxide.

[0014] The present invention is further configured that the material of the conductive metal tube is selected from a stainless steel metal tube and a copper metal tube; the resistivity of the conductive metal tube is (2.8-22.0)×10 -5 Ω·cm, the resistivity of the carbon felt is (2.5-4.5)×10 -5 Ω·cm.

[0015] The present invention is further configured such that the conductive metal tube has a built-in thermocouple for measuring the temperatures of the upper and lower surfaces of the SiSiC foam ceramic structure catalyst, and the outer layer of the thermocouple is covered with a capillary quartz tube for insulation treatment.

[0016] A second aspect of the present invention is to provide a method for preparing a SiSiC foam ceramic electrically driven reactor for hydrogen production by decomposing ammonia, comprising the following steps:

[0017] (1) preparing a powder catalyst by an impregnation method or a homogeneous precipitation method, wherein the powder catalyst is a catalyst prepared by loading one or more of Ru, Ni, Fe, Co, Rh, Pt and Pb on a carrier, and the carrier is aluminum oxide, silicon oxide or titanium oxide;

[0018] (2) preparing a catalyst slurry, wherein the components by weight are as follows: 1-3 wt% of polyethanol; 25-50 wt% of glycerol; 10-13 wt% of powdered catalyst; and the balance is deionized water;

[0019] Dissolve the powdered catalyst in the mixed solution of the remaining components, and ball-mill for 18-24 hours at a rotation speed of 50-150 rpm to obtain a catalyst slurry;

[0020] (3) immersing the SiSiC foam ceramic substrate in the above catalyst slurry, rotating in a high-speed centrifuge at 1000-2000 rpm for 2-4 min, and then drying in a muffle furnace at 300-500° C. for 10-30 min, and repeating multiple times;

[0021] (4) placing the dried SiSiC foam ceramic structure catalyst in a reduction furnace at 500-700° C. and introducing 50-100 mL / min of hydrogen for reduction for 2-5 hours;

[0022] (5) The reduced SiSiC foam ceramic structure catalyst is placed in a quartz tube, and then the carbon felt, conductive metal tube and thermocouple are loaded, and the conductive metal tube and the heating power supply are connected to complete the preparation of the SiSiC foam ceramic electric-driven reactor for ammonia decomposition to produce hydrogen.

[0023] The present invention is further configured such that the current supplied by the heating power supply is 1.2-5.0A.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] (1) The SiSiC foam ceramic matrix used in the SiSiC foam ceramic electric-driven reactor of the present invention has a high resistivity (up to 100Ω·cm), and its high resistivity enables it to directly convert electrical energy into thermal energy through resistance heating, thereby achieving rapid and uniform heating inside the electric-driven reactor and reducing power loss. In addition, SiSiC foam ceramic is a porous material with excellent mechanical strength and good chemical stability, and its open-pore structure provides a large specific surface area, which is conducive to uniform loading of the catalyst and efficient transfer of heat, thereby obtaining a highly uniform carrier-loaded metal catalyst coating.

[0026] (2) Compared with the traditional wall-heated reactor, the SiSiC foam ceramic electrically driven reactor prepared by the present invention has a faster heating rate inside the catalyst and a higher heat transfer efficiency, and its efficiency in catalytic decomposition of ammonia to produce hydrogen is also higher.

[0027] (3) Compared with the traditional wall-heated reactor, the SiSiC foam ceramic electric-driven reactor of the present invention can effectively reduce energy consumption and CO2 emissions during use, and can realize the miniaturization and integration of ammonia decomposition hydrogen production reactor, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the structure of a SiSiC foam ceramic electric-driven reactor used for hydrogen production by decomposing ammonia.

[0029] Figure 2 It is a schematic diagram of the structure of a traditional wall-heated reactor.

[0030] Figure 3 It is a comparison chart of the temperature rise response time of the SiSiC foam ceramic electric-driven reactor of the present invention and the traditional wall-heated reactor.

[0031] Figure 4 This is a comparison chart of the catalytic performance of ammonia decomposition of the SiSiC foam ceramic electric-driven reactor of the present invention and the traditional wall-heated reactor.

[0032] In the figure:

[0033] 1-quartz tube; 2-heating power supply; 3-SiSiC foam ceramic structure catalyst; 4-carbon felt; 5-conductive metal tube; 6-thermocouple; 7-powder catalyst. DETAILED DESCRIPTION

[0034] The technical solution of the present invention is described clearly and in detail by specific embodiments in conjunction with the accompanying drawings. It should be understood that the following embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Other embodiments obtained by ordinary technicians in this field without creative work should be included in the protection scope of the present invention.

[0035] like Figure 1 As shown, a SiSiC foam ceramic electric-driven reactor for hydrogen production by decomposing ammonia comprises a quartz tube 1 and a heating power source 2, as well as a SiSiC foam ceramic structure catalyst 3, a carbon felt 4 and two hollow conductive metal tubes 5 arranged inside the quartz tube 1, wherein the carbon felt 4 is arranged on the upper and lower sides of the SiSiC foam ceramic structure catalyst 3, one end of the conductive metal tube 5 is connected to the carbon felt 4, and the other end is externally connected to the heating power source 2;

[0036] The upper and lower ends of the quartz tube 1 are respectively an air inlet and an air outlet.

[0037] The present invention is further configured that the conductive metal tube 5 and the carbon felt 4 are both made of extremely low resistivity materials, and the material of the conductive metal tube 5 is selected from one of a stainless steel metal tube and a copper metal tube; preferably, the resistivity of the conductive metal tube 5 is (2.8-22.0)×10 -5 Ω·cm, the resistivity of the carbon felt 4 is (2.5-4.5)×10 -5 Ω·cm.

[0038] The present invention is further configured that the conductive metal tube 5 has a built-in thermocouple 6 for measuring the temperature of the upper and lower surfaces of the SiSiC foam ceramic structure catalyst 3;

[0039] The outer layer of the thermocouple 6 is sheathed with a capillary quartz tube (not shown in the figure) for insulation treatment.

[0040] The specific preparation process of the SiSiC foam ceramic electric-driven reactor for ammonia decomposition and hydrogen production is shown in the following Examples 1-4:

[0041] Example 1

[0042] S1: Preparation of SiSiC foam ceramic structured nickel-based catalyst

[0043] (1) Preparation of nickel-based alumina powder catalyst by impregnation method: 5.1 g of 0.4 M Ni(NO3)2·6H2O was dissolved in 40 mL of deionized water and then mixed with 3.20 g of γ-Al2O3 powder; the mixed solution was evaporated at 100°C; calcined at 600°C for 5 h in an air atmosphere; the obtained powder was placed in a reduction furnace at 500°C and reduced with 100 mL / min H2 for 4 h to obtain a Ni / Al2O3 powder catalyst.

[0044] (2) preparing an impregnation slurry: dissolving polyvinyl alcohol in deionized water at 85° C., then adding glycerol and stirring to dissolve, and finally adding the nickel-based alumina powder catalyst obtained in step (1) and ball milling at 80 rpm for 22 h to prepare an impregnation slurry; in the impregnation slurry, the mass proportion of each component is: polyvinyl alcohol 2.49 wt %, deionized water 37.34 wt %, glycerol 39.42 wt %, and nickel-based alumina powder catalyst 20.75 wt %.

[0045] (3) 1.23 g of SiSiC foam ceramic matrix with a porosity of 75% was placed in a muffle furnace and calcined for 10 h at 800° C.;

[0046] (4) placing the calcined SiSiC foam ceramic substrate into the impregnation slurry obtained in step (2) for 2 minutes, and then rotating it in a high-speed centrifuge at 1000 rpm for 2 minutes to remove excess slurry;

[0047] (5) Place in a muffle furnace at 400°C and dry for 20 min;

[0048] (6) the above-mentioned impregnation step (4) and drying step (5) are repeated multiple times;

[0049] (7) Finally, the obtained SiSiC foam ceramic structured nickel-based catalyst was placed in a reduction furnace and reduced by passing 100 mL / min of hydrogen at 500°C for 4 h.

[0050] S2: Assembly of the electrically driven reactor

[0051] First, a SiSiC foam ceramic structured nickel-based catalyst is placed in a quartz tube 1 with a diameter of 17.6 mm, and carbon felt 4 is filled on the upper and lower sides of the SiSiC foam ceramic structured nickel-based catalyst. One end of a conductive metal tube 5 is connected to the carbon felt 4, and the other end is connected to a heating power source 2 through an electrode clamp. A thermocouple 6 is placed in the conductive metal tube 5 and passes through the carbon felt 4 to connect to the surface of the SiSiC foam ceramic structured nickel-based catalyst, thereby completing the preparation of a SiSiC foam ceramic electrically driven reactor for hydrogen production by decomposing ammonia.

[0052] The heating power supply 2 is turned on, and current is passed through the conductive metal tube 5, the carbon felt 4 and the SiSiC foam ceramic structured nickel-based catalyst. The high resistivity of the SiSiC foam ceramic matrix is ​​used to generate a large Joule heat effect to supply energy for the ammonia decomposition reaction process.

[0053] Example 2

[0054] S1: Preparation of SiSiC foam ceramic structured nickel-based catalyst

[0055] (1) Preparation of nickel-based alumina powder catalyst by homogeneous precipitation method: Ni(NO3)2·6H2O and Al(NO3)3·9H2O were dissolved in deionized water to prepare nickel nitrate and aluminum nitrate solutions with concentrations of 0.086 mol / L and 0.102 mol / L, respectively; (NH2)2CO was dissolved in deionized water to form a 6 mol / L solution; the above solutions were mixed in a flask and reacted at 85°C for 10 h; the precipitate was filtered and washed with deionized water for 3 times; dried in an oven at 110°C for 12 h; the dried precipitate was calcined in a muffle furnace at 600°C for 5 h. The powder prepared above was placed in a 500°C reduction furnace and reduced with 100 mL / min H2 for 4 h to obtain a Ni / Al2O3 powder catalyst.

[0056] (2) preparing an impregnation slurry: dissolving polyvinyl alcohol in deionized water at 85° C., then adding glycerol and stirring to dissolve, and finally adding the Ni / Al2O3 powder catalyst obtained in step (1) and ball milling at 100 rpm for 20 h to prepare an impregnation slurry; in the impregnation slurry, the mass proportion of each component is: polyvinyl alcohol 1.27wt%, deionized water 47.77wt%, glycerol 35.03wt%, and nickel-based alumina powder catalyst 15.92wt%;

[0057] (3) 1.34 g of SiSiC foam ceramic matrix with a porosity of 50% was placed in a muffle furnace and calcined for 10 h at 800° C. for later use;

[0058] (4) placing the calcined SiSiC foam ceramic substrate into the impregnation slurry obtained in step (2) for 2 minutes, and then rotating it in a high-speed centrifuge at 2000 rpm for 2 minutes to remove excess slurry;

[0059] (5) Then place in a muffle furnace at 400°C and dry for 15 min;

[0060] (6) the above-mentioned impregnation step (4) and drying step (5) are repeated multiple times;

[0061] (7) Finally, the obtained SiSiC foam ceramic structured nickel-based catalyst was placed in a reduction furnace and reduced by passing 100 mL / min of hydrogen at 600°C for 3 h.

[0062] S2: Assembly of the electrically driven reactor

[0063] First, a SiSiC foam ceramic structured nickel-based catalyst is placed in a quartz tube 1 with a diameter of 17.6 mm, and carbon felt 4 is filled on the upper and lower sides of the SiSiC foam ceramic structured nickel-based catalyst. One end of a conductive metal tube 5 is connected to the carbon felt 4, and the other end is connected to a heating power source 2 through an electrode clamp. A thermocouple 6 is placed in the conductive metal tube 5 and passes through the carbon felt 4 to connect to the surface of the SiSiC foam ceramic structured nickel-based catalyst.

[0064] The heating power supply 2 is turned on, and current is passed through the conductive metal tube 5, the carbon felt 4 and the SiSiC foam ceramic structured nickel-based catalyst. The high resistivity of the SiSiC foam ceramic matrix is ​​used to generate a large Joule heat effect to supply energy for the ammonia decomposition reaction process.

[0065] Example 3

[0066] S1: Preparation of SiSiC foam ceramic structured ruthenium-based catalyst

[0067] (1) Preparation of ruthenium-based alumina powder catalyst by impregnation method: 1.20 g of γ-Al2O3 powder was dried at 120°C overnight, RuCl3 solution (7.5 wt% Ru) was added dropwise to the γ-Al2O3 powder, and finally dried at 80°C for 2 h;

[0068] (2) preparing an impregnation slurry: according to the mass ratio, polyvinyl alcohol is dissolved in deionized water at 85° C., glycerol is added and stirred to dissolve, and finally the ruthenium-based alumina powder catalyst obtained in step (1) is added and ball-milled at 80 rpm for 22 h to prepare an impregnation slurry; in the impregnation slurry, the mass proportions of the components are: polyvinyl alcohol 2.49 wt%, deionized water 37.34 wt%, glycerol 39.42 wt%, and ruthenium-based alumina powder catalyst 20.75 wt%;

[0069] (3) 1.32 g of SiSiC foam ceramic matrix with a porosity of 75% was placed in a muffle furnace and calcined for 10 h at 800° C. for later use;

[0070] (4) placing the calcined SiSiC foam ceramic substrate into the impregnation slurry obtained in step (2) for 2 minutes, and then rotating it in a high-speed centrifuge at 1000 rpm for 2 minutes to remove excess slurry;

[0071] (5) Then place in a muffle furnace at 400°C and dry for 20 min;

[0072] (6) the above-mentioned impregnation step (4) and drying step (5) are repeated multiple times;

[0073] (7) Finally, the obtained SiSiC foam ceramic structured ruthenium-based catalyst was placed in a reduction furnace and reduced by passing 50 mL / min of hydrogen at 500°C for 3 h.

[0074] S2: Assembly of the electrically driven reactor

[0075] First, a SiSiC foam ceramic structured ruthenium-based catalyst is placed in a quartz tube 1 with a diameter of 17.6 mm, and carbon felt 4 is filled on the upper and lower sides of the SiSiC foam ceramic structured ruthenium-based catalyst. One end of a conductive metal tube 5 is connected to the carbon felt 4, and the other end is connected to a heating power source 2 through an electrode clamp. A thermocouple 6 is placed in the conductive metal tube 5 and passes through the carbon felt 4 to connect to the surface of the SiSiC foam ceramic structured ruthenium-based catalyst.

[0076] The heating power supply 2 is turned on, and current is passed through the conductive metal tube 5, the carbon felt 4 and the SiSiC foam ceramic structured ruthenium-based catalyst. The high resistivity of the SiSiC foam ceramic matrix is ​​used to generate a large Joule heat effect to supply energy for the ammonia decomposition reaction process.

[0077] Example 4

[0078] S1: Preparation of SiSiC foam ceramic structured Ni-Fe based catalyst

[0079] (1) Preparation of nickel-iron-based bimetallic alumina powder catalyst by impregnation method: 0.298 g of Ni(NO3)2·6H2O and Fe(NO3)3·9H2O were dissolved in 100 mL of deionized water and stirred continuously. 1.8 g of γ-Al2O3 powder was added to the above solution at 90°C under magnetic stirring. After the solution was completely evaporated, the powder was collected and dried in an oven at 100°C for 12 h, and finally annealed in a muffle furnace at 700°C for 4 h.

[0080] (2) preparing an impregnation slurry: dissolving polyvinyl alcohol in % deionized water at 85° C., then adding glycerol and stirring to dissolve, and finally adding the nickel-iron-based bimetallic alumina powder catalyst obtained in step (1) and ball milling at 100 rpm for 20 h to prepare an impregnation slurry; in the impregnation slurry, the mass proportion of each component is: polyvinyl alcohol 1.27wt%, deionized water 47.77wt%, glycerol 35.03wt%, and nickel-iron-based bimetallic alumina powder catalyst 15.92wt%;

[0081] (3) 1.26 g of SiSiC foam ceramic matrix with a porosity of 50% was placed in a muffle furnace and calcined for 10 h at 800° C. for later use;

[0082] (4) placing the calcined SiSiC foam ceramic matrix into the slurry obtained in step (2) for 2 minutes, and then rotating it in a high-speed centrifuge at 2000 rpm for 2 minutes to remove excess slurry;

[0083] (5) Then place in a muffle furnace at 400°C and dry for 15 min;

[0084] (6) the above-mentioned impregnation step (4) and drying step (5) are repeated multiple times;

[0085] (7) Finally, the obtained SiSiC foam ceramic structured nickel-iron based catalyst was placed in a reduction furnace and reduced by passing 70 mL / min of hydrogen at 600 °C for 3 h.

[0086] S2: Assembly of the electrically driven reactor

[0087] First, a SiSiC foam ceramic structured nickel-iron-based catalyst is placed in a quartz tube 1 with a diameter of 17.6 mm, and carbon felt 4 is filled on the upper and lower sides of the SiSiC foam ceramic structured nickel-iron-based catalyst. One end of a conductive metal tube 5 is connected to the carbon felt 4, and the other end is connected to a heating power source 2 through an electrode clamp. A thermocouple 6 is placed in the conductive metal tube 5 and passes through the carbon felt 4 to connect to the surface of the SiSiC foam ceramic structured nickel-iron-based catalyst.

[0088] The heating power supply 2 is turned on, and current is passed through the conductive metal tube 5, the carbon felt 4 and the SiSiC foam ceramic structured nickel-iron based catalyst. The high resistivity of the SiSiC foam ceramic matrix is ​​used to generate a large Joule heat effect to supply energy for the ammonia decomposition reaction process.

[0089] Comparative Example 1

[0090] like Figure 2As shown, the conventional wall-heated catalytic reactor comprises a quartz tube 1, and a powder catalyst 7, a carbon felt 4 and a thermocouple 6 arranged inside the quartz tube 1, wherein the carbon felt 4 is arranged on the upper and lower sides of the powder catalyst 7, and the thermocouple 6 passes through the carbon felt 4 and is connected to the surface of the powder catalyst 6, and is used to measure the temperature of the upper and lower surfaces of the powder catalyst 7;

[0091] The upper and lower ends of the quartz tube 1 are respectively an air inlet and an air outlet.

[0092] The preparation process of the above-mentioned conventional wall-heated catalytic reactor is as follows:

[0093] S1: Preparation of powdered catalyst

[0094] (1) Preparation of nickel-based alumina powder catalyst by impregnation method: 5.1 g of Ni(NO3)2·6H2O was dissolved in 40 mL of deionized water and mixed with 3.2 g of γ-Al2O3 powder; the mixed solution was evaporated at 100°C; calcined at 600°C for 5 h in an air atmosphere; the prepared powder was placed in a reduction furnace at 500°C and reduced with 100 mL / min H2 for 4 h to obtain a Ni / Al2O3 powder catalyst.

[0095] S2: Assembly of a conventional wall-heated catalytic reactor

[0096] First, Ni / Al2O3 powder catalyst is placed in a quartz tube 1, and carbon felt 4 is filled on the upper and lower sides of the Ni / Al2O3 powder catalyst. A thermocouple 6 passes through the carbon felt 4 and is connected to the surface of the Ni / Al2O3 powder catalyst, and the catalyst is heated by a heating furnace.

[0097] Application Examples

[0098] The SiSiC foam ceramic electric driven reactor prepared in the above-mentioned Example 1 and Example 2 and the conventional wall-heated catalytic reactor of Comparative Example 1 were used to carry out a test on catalytic ammonia decomposition and hydrogen production, as follows:

[0099] Pure ammonia gas was introduced into the electrically driven reactor prepared in Example 1, and a power source was connected to pass a current of 1.2-4.4 A to provide in-situ heat on the catalyst.

[0100] Pure ammonia gas was introduced into the electrically driven reactor prepared in Example 2, and a power source was connected to pass a current of 1.5-5.0 A to provide in-situ heat on the catalyst.

[0101] Pure ammonia gas was introduced into the conventional wall-heated catalytic reactor of Comparative Example 1, and the heating furnace was turned on to heat the catalyst.

[0102] Figure 3 It is the temperature response diagram of the SiSiC foam ceramic electric driven reactor of Example 1 and the traditional wall-heated catalytic reactor of Comparative Example 1. Figure 4 This is a comparison chart of the catalytic performance of ammonia decomposition of the SiSiC foam ceramic electric-driven reactors of Examples 1 and 2 and the traditional wall-heated catalytic reactor of Comparative Example 1.

[0103] Depend on Figure 3 and Figure 4 It can be seen that the electrically driven reactor of the present invention can quickly reach the set reaction temperature, and the ammonia decomposition and hydrogen production reaction occurs rapidly in the catalytic area to produce hydrogen; the ammonia conversion rate is also significantly better than that of traditional wall-heated catalytic reactors.

[0104] The above embodiments have described the technical solutions of the present application in detail, but they are not intended to limit the protection scope of the present invention. All equivalent modifications made within the principles and spirit of the present application are within the protection scope of the present invention.

Claims

1. A SiSiC ceramic foam electric-driven reactor for hydrogen production by decomposing ammonia, characterized in that: It comprises a quartz tube and a heating power source, and a SiSiC foam ceramic structure catalyst, a carbon felt and two hollow conductive metal tubes arranged inside the quartz tube, wherein the carbon felt is arranged on the upper and lower sides of the SiSiC foam ceramic structure catalyst, one end of the conductive metal tube is connected to the carbon felt, and the other end is connected to an external heating power source; The upper and lower ends of the quartz tube are respectively an air inlet and an air outlet.

2. The SiSiC foam ceramic electric driven reactor for hydrogen production by decomposing ammonia according to claim 1, characterized in that: The SiSiC foam ceramic structure catalyst consists of a SiSiC foam ceramic matrix, an oxide carrier and a metal-based active component supported on the oxide carrier.

3. The SiSiC foam ceramic electric driven reactor for hydrogen production by decomposing ammonia according to claim 2, characterized in that: The mass composition of the SiSiC foam ceramic structure catalyst is 0.6-3wt% of metal-based active components, 10.4-12wt% of carriers, and 85-88wt% of SiSiC foam ceramic matrix.

4. The SiSiC foam ceramic electric driven reactor for hydrogen production by decomposing ammonia according to claim 3, characterized in that: The porosity of the SiSiC foam ceramic matrix is ​​50-80%.

5. The SiSiC foam ceramic electric driven reactor for hydrogen production by decomposing ammonia according to claim 3, characterized in that: The metal-based active component is selected from one or more of Ru, Ni, Fe, Co, Rh, Pt and Pb.

6. The SiSiC foam ceramic electric driven reactor for hydrogen production by decomposing ammonia according to claim 3, characterized in that: The oxide carrier is one or more of aluminum oxide, silicon oxide and titanium oxide, preferably aluminum oxide.

7. The SiSiC foam ceramic electric driven reactor for hydrogen production by decomposing ammonia according to claim 1, characterized in that: The material of the conductive metal tube is selected from a stainless steel metal tube and a copper metal tube; the resistivity of the conductive metal tube is (2.8-22.0)×10 -5 Ω·cm, the resistivity of the carbon felt is (2.5-4.5)×10 -5 Ω·cm.

8. The SiSiC ceramic foam electric driven reactor for hydrogen production by decomposing ammonia according to claim 1, characterized in that: The conductive metal tube has a built-in thermocouple for measuring the temperatures of the upper and lower surfaces of the SiSiC foam catalyst; The outer layer of the thermocouple is covered with a capillary quartz tube for insulation treatment.

9. The method for preparing the SiSiC foam ceramic electric-driven reactor for hydrogen production by decomposing ammonia according to any one of claims 1 to 8, characterized in that: The following steps are involved: (1) preparing a powder catalyst by an impregnation method or a homogeneous precipitation method, wherein the powder catalyst is a catalyst prepared by loading one or more of Ru, Ni, Fe, Co, Rh, Pt and Pb on a carrier, and the carrier is aluminum oxide, silicon oxide or titanium oxide; (2) preparing a catalyst slurry, wherein the components by weight are as follows: 1-3 wt% of polyethanol; 25-50 wt% of glycerol; 10-13 wt% of powdered catalyst; and the balance is deionized water; Dissolve the powdered catalyst in the mixed solution of the remaining components, and ball-mill for 18-24 hours at a rotation speed of 50-150 rpm to obtain a catalyst slurry; (3) immersing the SiSiC foam ceramic substrate in the above catalyst slurry, rotating in a high-speed centrifuge at 1000-2000 rpm for 2-4 min, and then drying in a muffle furnace at 300-500° C. for 10-30 min, and repeating multiple times; (4) placing the dried SiSiC foam ceramic structure catalyst in a reduction furnace at 500-700° C. and introducing 50-100 mL / min of hydrogen for reduction for 2-5 hours; (5) The reduced SiSiC foam ceramic structure catalyst is placed in a quartz tube, and then the carbon felt, conductive metal tube and thermocouple are loaded, and the conductive metal tube and the heating power supply are connected to complete the preparation of the SiSiC foam ceramic electric-driven reactor for ammonia decomposition to produce hydrogen.

10. The method for preparing the SiSiC foam ceramic electric-driven reactor for hydrogen production by decomposing ammonia according to claim 9, characterized in that: The current supplied by the heating power supply is 1.2-5.0A.

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