Preparation method and application of bimetallic catalyst for dehydrogenation of organic liquid

Abstract

The invention is suitable for the technical field of organic liquid dehydrogenation, and provides a preparation method and application of a bimetallic catalyst for organic liquid dehydrogenation, and the method comprises the following steps: preparing a nickel-tin salt solution as an impregnation liquid according to the saturated water absorption capacity of a carrier and an impregnation method, and mixing and stirring the carrier and the impregnation liquid; stirring, draining, aging and drying to obtain a catalyst precursor; roasting the catalyst precursor to obtain a bimetallic catalyst; and placing the bimetallic catalyst in a reduction gas flow to carry out a reduction reaction for later use. The metal components in the prepared bimetallic catalyst are uniformly dispersed, and the synergism among different metals is good; the non-noble metal catalyst can be used for dehydrogenation reaction of dibenzyltoluene hydrogen storage liquid, has excellent dehydrogenation performance, and can reduce carbon deposition in the reaction process and reduce loss of dehydrogenation raw materials. In addition, the non-noble metal catalyst prepared by the method avoids using expensive noble metal materials, so that the cost of an organic liquid dehydrogenation catalyst is remarkably reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of organic liquid dehydrogenation, and in particular relates to a preparation method and application of a bimetallic catalyst for organic liquid dehydrogenation. Background Art

[0002] The storage and transportation of hydrogen must take into account cost and convenience. As common means of hydrogen storage and transportation, high-pressure gaseous hydrogen storage and low-temperature liquid hydrogen storage have the key problem of achieving large-scale low-cost transportation. There are relatively strict requirements on the material of the container, and there are certain safety risks. In addition, the cooling cost of low-temperature liquid hydrogen storage is also a problem. Other emerging hydrogen storage methods such as adsorption hydrogen storage, complex hydrogen storage, and metal hydride hydrogen storage also have major problems in terms of material cost, complexity of the hydrogen storage and decomposition process, operating cost, and dielectric loss.

[0003] Since the benzene ring structure naturally has the ability to bind hydrogen molecules through chemical reactions and release them reversely, and the aromatic compounds themselves have excellent thermal stability, aromatic compounds with two or more rings are liquid at room temperature and can be transported directly through current petrochemical pipelines, greatly reducing the channel laying problems faced by large-scale applications in the later stage. Therefore, liquid hydrogen storage liquid is a very excellent hydrogen storage and release medium, and the focus of restricting its development is the catalyst.

[0004] Precious metal catalysts such as platinum, palladium, and ruthenium are widely used in the field of dehydrogenation due to their outstanding high activity. However, the high cost caused by the scarce stock is an inevitable problem that leads to the further expansion of the dehydrogenation industry. Therefore, the academic community began to invest time in the field of non-precious metal catalysis. Among them, nickel has a dehydrogenation ability similar to that of precious metals and is widely used. The low cost of nickel can increase the nickel loading as one of the means to improve the activity of the catalyst. However, nickel-based catalysts with a single metal component have several key problems in the field of dehydrogenation, such as low dehydrogenation activity, low selectivity, and poor stability. Therefore, it is necessary to improve the production process of nickel-based catalysts to reduce process costs and improve the hydrogen release efficiency in the middle end of the hydrogen energy industry chain. Summary of the invention

[0005] The purpose of the embodiments of the present invention is to provide a preparation method and application of a bimetallic catalyst for dehydrogenation of an organic liquid, aiming to solve the problems raised in the above background technology.

[0006] The embodiment of the present invention is implemented as follows: a method for preparing a bimetallic catalyst for dehydrogenation of an organic liquid comprises the following steps:

[0007] Step 1: prepare a nickel-tin salt solution as an impregnation solution according to the saturated water absorption capacity of the carrier and the impregnation method, and mix and stir the carrier and the impregnation solution;

[0008] Step 2: After stirring, draining, aging and drying to obtain a catalyst precursor;

[0009] Step 3: calcining the catalyst precursor to obtain a bimetallic catalyst;

[0010] Step 4: placing the bimetallic catalyst in a reducing gas stream for reduction reaction and setting aside.

[0011] According to a further technical solution, in step 1, the nickel metal salt is a nitrate, an acetate, a halide or a sulfate, and the tin metal salt is a halide.

[0012] As a preferred embodiment of the present invention, the active metal nickel loading in the bimetallic catalyst is 1%-30%, and the molar ratio of nickel to tin is 1:0-1:2.

[0013] As a preferred embodiment of the present invention, in step 1, during the impregnation, the ratio of the volume of the impregnation liquid to the saturated water absorption capacity of the carrier is 1:1-1:10.

[0014] As a preferred embodiment of the present invention, in step 1, the impregnation liquid and the carrier are mixed by dripping the impregnation liquid onto the carrier or pouring the carrier into the impregnation liquid.

[0015] As a preferred embodiment of the present invention, in step 1, the impregnation carrier is one or more of aluminum oxide, titanium oxide, molybdenum oxide, silicon oxide and molecular sieve.

[0016] As a preferred embodiment of the present invention, in step 4, the reducing gas is hydrogen with a purity of 5%-100%, and the rest is inert gas, and the components are one or more of nitrogen and argon, but not limited to this; the temperature of the reduction reaction is 150-600°C; the time of the reduction reaction is 0.5-12h; the reducing gas flow rate of the reduction reaction is 50-500mL / min.

[0017] Another object of an embodiment of the present invention is to provide an application of a bimetallic catalyst for dehydrogenation of an organic liquid, based on the bimetallic catalyst prepared by the above method, and applying the reduced bimetallic catalyst to the dehydrogenation reaction of a hydrogen storage liquid.

[0018] In a further technical solution, when the bimetallic catalyst is used, the reaction temperature is 280-400°C, the dehydrogenation pressure is 0-1MPa, and the mass space velocity is 0-10h -1 .

[0019] The present invention provides a method for preparing a bimetallic catalyst for dehydrogenation of an organic liquid and its application. The metal components in the prepared bimetallic catalyst are evenly dispersed, and the synergy between different metals is good. The non-precious metal catalyst can be used for the dehydrogenation reaction of dibenzyltoluene hydrogen storage liquid, has excellent dehydrogenation performance, and can also reduce carbon deposition during the reaction process and reduce the loss of dehydrogenation raw materials. In addition, the non-precious metal catalyst prepared by the method avoids the use of expensive precious metal materials, significantly reducing the cost of the organic liquid dehydrogenation catalyst. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Comparison of catalyst stability before and after modification in Example 1 (reaction temperature 330°C, mass space velocity 2g 全氢二苄基甲苯 / (g 催化剂 h));

[0021] Figure 2 Comparison of catalyst stability before and after modification in Example 2 (reaction temperature 330°C, mass space velocity 2g 全氢二苄基甲苯 / (g 催化剂 h));

[0022] Figure 3 Comparison of catalyst stability before and after modification in Example 3 (reaction temperature 330°C, mass space velocity 2g 全氢二苄基甲苯 / (g 催化剂 h));

[0023] Figure 4 Comparison of catalyst stability before and after modification in Example 4 (reaction temperature 330°C, mass space velocity 2g 全氢二苄基甲苯 / (g 催化剂 h)). DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0025] The specific implementation of the present invention is described in detail below in conjunction with specific embodiments.

[0026] An embodiment of the present invention provides a method for preparing a bimetallic catalyst for dehydrogenation of an organic liquid, comprising the following steps:

[0027] Step 1: prepare a nickel-tin salt solution as an impregnation solution according to the saturated water absorption capacity of the carrier and the impregnation method, and mix and stir the carrier and the impregnation solution;

[0028] Step 2: After stirring, draining, aging and drying to obtain a catalyst precursor;

[0029] Step 3: calcining the catalyst precursor to obtain a bimetallic catalyst;

[0030] Step 4: placing the bimetallic catalyst in a reducing gas stream for reduction reaction and setting aside.

[0031] As a preferred embodiment of the present invention, in step 1, the nickel metal salt is a nitrate, an acetate, a halide or a sulfate, and the tin metal salt is a halide.

[0032] As a preferred embodiment of the present invention, the active metal nickel loading in the bimetallic catalyst is 1%-30%, preferably 10-30%; the molar ratio of nickel to tin is 1:0-1:2, preferably 1:0-1:1.

[0033] As a preferred embodiment of the present invention, in step 1, during the impregnation, the ratio of the volume of the impregnation liquid to the saturated water absorption capacity of the carrier is 1:1-1:10, preferably 1:1-1:3.

[0034] As a preferred embodiment of the present invention, in step 1, the impregnation liquid and the carrier are mixed by dripping the impregnation liquid onto the carrier or pouring the carrier into the impregnation liquid.

[0035] As a preferred embodiment of the present invention, in step 1, the impregnation carrier is one or more of aluminum oxide, titanium oxide, molybdenum oxide, silicon oxide and molecular sieve.

[0036] As a preferred embodiment of the present invention, in step 1, during the stirring process, the stirring temperature is room temperature; the stirring time is 0-8h, preferably 0.5-6h, and more preferably 1-3h.

[0037] As a preferred embodiment of the present invention, in step 2, the aging time is 0-48h, preferably 1-24h, more preferably 2-12h; the drying temperature is 40-160°C, preferably 60-140°C.

[0038] As a preferred embodiment of the present invention, in step 3, the calcination temperature is 300-800°C, preferably 300-500°C; the calcination time is 1-12h, preferably 2-10h, and more preferably 3-6h.

[0039] As a preferred embodiment of the present invention, in step 4, the reducing gas is hydrogen with a purity of 5%-100%, and the rest is inert gas, and the components are one or more of nitrogen and argon, but not limited to this; the temperature of the reduction reaction is 150-600°C, preferably 200-500°C; the time of the reduction reaction is 0.5-12h, preferably 1-50h, and more preferably 2-6h; the reducing gas flow rate of the reduction reaction is 50-500mL / min, preferably 50-400mL / min, and more preferably 100-300mL / min.

[0040] Another embodiment of the present invention provides an application of a bimetallic catalyst for dehydrogenation of an organic liquid. Based on the bimetallic catalyst prepared by the above method, the reduced bimetallic catalyst is applied to the dehydrogenation reaction of a hydrogen storage liquid.

[0041] As a preferred embodiment of the present invention, the hydrogen storage liquid is perhydrodibenzyltoluene.

[0042] As a preferred embodiment of the present invention, when the bimetallic catalyst is used, the reaction temperature is 280-400°C, preferably 280-330°C; the dehydrogenation pressure is 0-1MPa; the mass space velocity is 0-10h -1 , preferably 1-5h -1 .

[0043] The following provides several specific implementation cases and application cases of this method in practical applications.

[0044] Example 1: The preparation method of the bimetallic catalyst comprises the following steps:

[0045] S1. Weigh an alumina carrier with a known saturated water absorption rate, select nickel nitrate and stannous chloride as metal salts to prepare an impregnation solution, with a nickel loading of 15% and a nickel-tin molar ratio of 30:1. Use an excess impregnation method with a ratio of the impregnation solution volume to the saturated water absorption of 1:3. Pour the carrier into the impregnation solution and stir for 2 hours.

[0046] S2. After stirring, drain, let stand for aging at room temperature for 6 hours, and place in an oven at 100°C for drying overnight.

[0047] S3. After drying, calcine at 500°C for 6h.

[0048] S4. After the calcination is completed, the catalyst is placed in a tubular furnace and an activation gas of 100% purity hydrogen is introduced at a flow rate of 200 mL / min. The temperature is raised to 300° C. and activated at this temperature for 8 h to obtain a bimetallic catalyst for standby use.

[0049] Example 2: The preparation method of the bimetallic catalyst comprises the following steps:

[0050] S1. Weigh an alumina carrier with a known saturated water absorption rate, select nickel chloride and tin tetrachloride as metal salts to prepare an impregnation solution, with a nickel loading of 10% and a nickel-tin molar ratio of 10:1. Use an equal volume impregnation method with a ratio of the impregnation solution volume to the saturated water absorption of 1:1. Pour the carrier into the impregnation solution and stir for 6 hours.

[0051] S2. After stirring, drain, let stand for aging at room temperature for 4 hours, and place in an oven at 80°C for drying overnight.

[0052] S3. After drying, calcine at 400°C for 4h.

[0053] S4. After the calcination is completed, the catalyst is placed in a tubular furnace and an activation gas of 30% purity hydrogen is introduced at a flow rate of 250 mL / min. The temperature is raised to 250° C. and activated at this temperature for 2 h to obtain a bimetallic catalyst for standby use.

[0054] Example 3: The preparation method of the bimetallic catalyst comprises the following steps:

[0055] S1. Weigh an alumina carrier with a known saturated water absorption rate, select nickel acetate and stannous chloride as metal salts to prepare an impregnation solution, with a nickel loading of 12% and a nickel-tin molar ratio of 14:1. Use an excess impregnation method with a ratio of the impregnation solution volume to the saturated water absorption of 1:2. Add the impregnation solution dropwise onto the carrier and stir for 3 hours.

[0056] S2. After stirring, drain, let stand for aging for 5 hours at room temperature, and place in an oven at 120°C for drying overnight.

[0057] S3. After drying, calcine at 450°C for 5h.

[0058] S4. After the calcination is completed, the mixture is placed in a tubular furnace and an activation gas with a purity of 10% and a flow rate of 150 mL / min of hydrogen is introduced. The temperature is raised to 400° C. and activated at this temperature for 8 h to obtain a bimetallic catalyst for standby use.

[0059] Example 4: The preparation method of the bimetallic catalyst comprises the following steps:

[0060] S1. Weigh an alumina carrier with a known saturated water absorption rate, select nickel sulfate and tin tetrachloride as metal salts to prepare an impregnation solution, with a nickel loading of 30% and a nickel-tin molar ratio of 20:1. Use an equal volume impregnation method with a ratio of the impregnation solution volume to the saturated water absorption of 1:1. Add the impregnation solution dropwise onto the carrier and stir for 5 hours.

[0061] S2. After stirring, drain, let stand for aging at room temperature for 10 hours, and place in an oven at 90°C for drying overnight.

[0062] S3. After drying, calcine at 350°C for 6h.

[0063] S4. After the calcination is completed, the catalyst is placed in a tubular furnace and an activation gas of 60% purity of hydrogen is introduced at a flow rate of 400 mL / min, the temperature is raised to 200° C., and activated at this temperature for 4 h to obtain a bimetallic catalyst for standby use.

[0064] Application Example: The bimetallic catalysts prepared in the above Examples 1 to 5 and the nickel-based monometallic catalysts prepared under the same conditions in the same steps were applied to the dehydrogenation reaction of perhydrodibenzyltoluene hydrogen storage liquid. The test results are shown in Table 1 and Figure 1-4 shown.

[0065] The test method is as follows: weigh 4.3 g of the above catalyst and load it into the reaction device. After purging with inert gas, start the metering pump to inject the sample. After the raw material enters the reaction area, heat it to the reaction temperature to start the reaction. After reacting for 5 hours, take the dehydrogenated liquid for analysis by chromatography. After reacting for 40, 80, 120, 160, and 200 hours, take the dehydrogenated liquid for analysis.

[0066] Table 1 Comparison of dehydrogenation results of catalysts with different active components in different embodiments

[0067]

[0068] From the above results, it can be seen that the bimetallic catalyst prepared by this method has high dehydrogenation performance and inhibits cracking in the dehydrogenation of hydrogen storage liquid.

[0069] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a bimetallic catalyst for dehydrogenation of an organic liquid, characterized in that: The following steps are involved: Step 1: prepare a nickel-tin salt solution as an impregnation solution according to the saturated water absorption capacity of the carrier and the impregnation method, and mix and stir the carrier and the impregnation solution; Step 2: After stirring, draining, aging and drying to obtain a catalyst precursor; Step 3: calcining the catalyst precursor to obtain a bimetallic catalyst; Step 4: placing the bimetallic catalyst in a reducing gas stream for reduction reaction and setting aside.

2. The method for preparing a bimetallic catalyst for dehydrogenation of an organic liquid according to claim 1, characterized in that: In step 1, the nickel metal salt is nitrate, acetate, halide or sulfate, and the tin metal salt is halide.

3. The method for preparing a bimetallic catalyst for dehydrogenation of an organic liquid according to claim 1, characterized in that: The active metal nickel loading in the bimetallic catalyst is 1%-30%, and the molar ratio of nickel to tin is 1:0-1:

2.

4. The method for preparing a bimetallic catalyst for dehydrogenation of an organic liquid according to claim 2, characterized in that: In the step 1, during the impregnation, the ratio of the volume of the impregnation liquid to the saturated water absorption capacity of the carrier is 1:1-1:

10.

5. The method for preparing a bimetallic catalyst for dehydrogenation of an organic liquid according to claim 2, characterized in that: In step 1, the impregnation liquid and the carrier are mixed by dripping the impregnation liquid onto the carrier or pouring the carrier into the impregnation liquid.

6. The method for preparing a bimetallic catalyst for dehydrogenation of an organic liquid according to claim 2, characterized in that: In step 1, the impregnation carrier is one or more of aluminum oxide, titanium oxide, molybdenum oxide, silicon oxide and molecular sieve.

7. The method for preparing a bimetallic catalyst for dehydrogenation of an organic liquid according to claim 1, characterized in that: In step 4, the reducing gas is hydrogen with a purity of 5%-100%, and the rest is inert gas, and the components are one or more of nitrogen and argon; the temperature of the reduction reaction is 150-600°C; the time of the reduction reaction is 0.5-12h; the reducing gas flow rate of the reduction reaction is 50-500mL / min.

8. An application of a bimetallic catalyst for dehydrogenation of an organic liquid, the bimetallic catalyst prepared by the preparation method of the bimetallic catalyst for dehydrogenation of an organic liquid according to any one of claims 1 to 7, characterized in that: The reduced bimetallic catalyst is applied to the dehydrogenation reaction of hydrogen storage liquid.

9. The use of the bimetallic catalyst for dehydrogenation of organic liquid according to claim 8, characterized in that: When the bimetallic catalyst is used, the reaction temperature is 280-400°C, the dehydrogenation pressure is 0-1MPa, and the mass space velocity is 0-10h -1 .

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