Process for the preparation of a platinum on carbon on silica catalyst for the dehydrogenation of methylcyclohexane

Abstract

The application discloses a method for preparing a Pt-SiO2 catalyst for methylcyclohexane dehydrogenation from coal, and utilizes coal as a raw material to obtain porous carbon-doped SiO2 through high-temperature gasification, hydrochloric acid treatment, high-temperature calcination and the like, and further obtains porous carbon-doped Pt-SiO2 catalyst through impregnation, calcination and reduction in the porous carbon-doped SiO2; and finally realizes efficient and long-acting catalysis of methylcyclohexane dehydrogenation by the porous carbon-doped Pt-SiO2 catalyst. The Pt-SiO2 catalyst prepared by the application is used for catalyzing methylcyclohexane dehydrogenation, and not only solves the current problem of hydrogen storage and transportation difficulty, but also has relatively high dehydrogenation efficiency.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of liquid organic molecular carrier preparation, and relates to a method for preparing a coal-methylcyclohexane dehydrogenation Pt-SiO2 catalyst. BACKGROUND

[0002] Hydrogen storage and transportation is an important part of hydrogen energy popularization and application. The mass energy density of hydrogen is large, the volume energy density is small, and hydrogen is flammable and explosive. Traditional physical hydrogen storage and transportation technology (high pressure compression, low temperature liquefaction) cannot meet the demand, and new hydrogen storage and transportation technology needs to be developed. Liquid organic molecular carrier hydrogen storage is a new type of chemical hydrogen storage method, and the core process includes organic molecular dehydrogenation technology. Practice shows that the current organic molecular dehydrogenation technology is not very mature, and the dehydrogenation effect is not ideal, so a hydrogen production method with high dehydrogenation efficiency and convenient hydrogen storage and transportation is needed. SUMMARY

[0003] The purpose of the present application is to provide a method for preparing a coal-methylcyclohexane dehydrogenation Pt-SiO2 catalyst, which is used for catalyzing methylcyclohexane dehydrogenation. The Pt-SiO2 catalyst prepared by the method not only solves the problem of hydrogen storage and transportation, but also has high dehydrogenation efficiency.

[0004] The technical scheme adopted by the present application is a method for preparing a coal-methylcyclohexane dehydrogenation Pt-SiO2 catalyst, which specifically comprises the following steps:

[0005] Step 1, porous carbon-SiO2 is prepared from coal;

[0006] Step 2, porous carbon-Pt-SiO2 is prepared from the porous carbon-SiO2 obtained in step 1.

[0007] The present application has the following characteristics:

[0008] The specific process of step 1 is as follows:

[0009] Step 1.1, 1kg-5kg of coal is taken, and coal powder with a particle size of 300-500 meshes is selected by grinding and sieving, 1kg-10kg of water and 0.01g-0.2g of dispersant lignin sulfonate are added, and stirring is carried out for 30min-60min to obtain a slurry;

[0010] Step 1.2, the slurry prepared in step 1.1 is placed in an entrained bed, air is introduced, the pressure is 3MPa-5MPa, and the gasification is carried out at 1200℃-1500℃ for 5min-50min, and then the solid material 0.1kg-0.5kg is collected after cooling;

[0011] Step 1.3, the solid collected in step 1.2 is sieved to obtain solid with particle size less than 200 mesh, 5g-10g of the solid is mixed with 20%-25% hydrochloric acid and stirred for 3h-5h, then the mixed solution is washed and filtered by diluting with deionized water, and the filter cake is dried in a vacuum drying oven at 105℃-130℃, then put into a muffle furnace, when the temperature reaches 600℃-800℃, calcine in air for 3h-5h, to obtain a porous carbon-doped SiO2 carrier.

[0012] The specific process of step 2 is as follows:

[0013] Step 2.1, prepare platinum nitrate composite porous carbon-doped SiO2 according to the porous carbon-doped SiO2 obtained in step 1.

[0014] Step 2.2, put the platinum nitrate composite porous carbon-doped SiO2 prepared in step 2.1 into a muffle furnace, the heating rate is 5℃ / min-15℃ / min, when the temperature reaches the set temperature, calcine in air, cool to room temperature, and then reduce in H2, to finally obtain porous carbon-doped Pt-SiO2.

[0015] The specific process of step 2.1 is as follows:

[0016] Take 2g-6g of porous carbon-doped SiO2 and disperse it in 10-30mL of deionized water, add 0.3g-0.9g of platinum nitrate, mix and stir uniformly at room temperature, and then dry in a vacuum drying oven at 105℃-130℃, to obtain platinum nitrate composite porous carbon-doped SiO2.

[0017] The process of porous carbon-doped Pt-SiO2 catalyzing the hydrogen production of methylcyclohexane is as follows:

[0018] After the porous carbon-doped Pt-SiO2 catalyst is uniformly stirred with quartz sand, it is put into a high-pressure catalytic fixed bed, the gas flow rate is 35mL / min-50mL / min, the pressure is 0.3MPa-0.6MPa, the methylcyclohexane sample speed is 0.05mL / min-0.15mL / min, and the catalytic reaction temperature is 330℃-410℃.

[0019] The beneficial effects of the present application are that coal is used as a raw material to prepare porous carbon-doped SiO2, and Pt catalytic active centers are further introduced to improve catalytic activity, the conversion rate of porous carbon-doped Pt-SiO2 catalyzing the dehydrogenation of methylcyclohexane is more than 95%, and the hydrogen release concentration does not decrease significantly (decrease rate is less than 2.5%) for a long catalytic time of 100h. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is the SEM test result of the porous carbon-doped SiO2 prepared in the method example 1 of the present application for preparing a methylcyclohexane dehydrogenation Pt-SiO2 catalyst.

[0021] Figures 2(a) to 2(c) Figure 2 is the XPS test results of the porous carbon-doped Pt-SiO2 before and after hydrogen reduction, wherein Figure 2(a) is a full spectrum test chart, Figure 2(b) is a high-resolution C1s test chart, and Figure 2(c) is a high-resolution Pt 4f test chart;

[0022] Figure 3 Figure 3 is an EDS chart of Pt in the carbon-doped SiO2 structure in the method for preparing a coal-methylcyclohexane dehydrogenation Pt-SiO2 catalyst according to the present application, wherein, Figure 3 (a) is an SEM chart, Figure 3 (b) is a Pt EDS chart, Figure 3 (c) is an O EDS chart, Figure 3 (d) is a Si EDS chart;

[0023] Figure 4 Figure 4 is a performance effect chart of the porous carbon-doped Pt-SiO2 catalyst catalyzing methylcyclohexane dehydrogenation in the method for preparing a coal-methylcyclohexane dehydrogenation Pt-SiO2 catalyst according to the present application. DETAILED DESCRIPTION

[0024] The present application will be described in detail below in conjunction with the drawings and specific embodiments.

[0025] The method for preparing a coal-methylcyclohexane dehydrogenation Pt-SiO2 (platinum-based carbon-doped silicon dioxide) catalyst according to the present application comprises the following steps:

[0026] Step 1, preparation of porous carbon-doped SiO2

[0027] Take 1-5 kg of coal, grind and sieve the particle size to select 300-500 mesh coal powder, add 1-10 kg of water and 0.01-0.2 g of dispersant lignin sulfonate, uniformly stir for 30-60 min to obtain a slurry. Put the slurry into a micro-fluidized bed, pass in air, the pressure is 3-5 MPa, and gasify at 1200-1500℃ for 5-50 min, then collect the solid 0.1-0.5 kg after cooling. Sieve the collected solid to obtain solid with a particle size of less than 200 mesh, mix 5-10 g of the solid with 20-25% hydrochloric acid, then stir for 3-5 h, then dilute and wash the mixed solution with deionized water and filter, dry the filter cake in a vacuum drying box at 105-130℃ for 12 h, then put it into a muffle furnace, the heating rate is 5℃ / min, when the temperature reaches 600-800℃, calcine it under air conditions for 3-5 h to obtain a porous carbon-doped SiO2 carrier.

[0028] Step 2, preparation of porous carbon-doped Pt-SiO2

[0029] Take 2-6 g of porous carbon impregnated SiO2dispersed in 10-30 mL of deionized water, add 0.3-0.9 g of platinum nitrate, mix and stir at room temperature for 12 h, then place in a vacuum drying oven at 105-130 °C for 12 h to obtain platinum nitrate composite porous carbon impregnated SiO2. Put the above composite into a muffle furnace, the heating rate is 5-15 °C / min, when the temperature reaches 300 °C, calcine in air for 3 h, cool to room temperature and reduce in H2for 3 h, finally obtain porous carbon impregnated Pt-SiO2.

[0030] Hydrogen production performance of porous carbon impregnated Pt-SiO2catalyst

[0031] Take 0.2 g of porous carbon impregnated Pt-SiO2catalyst and 3 g of quartz sand, mix and stir uniformly, then put into a high-pressure catalytic fixed bed, gas flow rate is 35-50 mL / min, pressure is 0.3-0.6 MPa, methylcyclohexane sample speed is 0.05-0.15 mL / min, catalytic reaction temperature is 330-410 °C.

[0032] Example 1

[0033] Step 1, preparation of porous carbon impregnated SiO2

[0034] Take 1 kg of Shanbei Jurassic coal, grind and sieve to select 300 mesh coal powder, add 1 kg of water and 0.01 g of dispersant lignosulfonate, mix and stir uniformly for 30 min to obtain a slurry. Put the slurry into a micro-fluidized bed and pass in air, the pressure is 3 MPa, gasify at 1200 °C for 5 min, cool and collect 0.1 kg of solid. Sieve the collected solid to obtain solid with particle size less than 200 mesh, mix 5 g of the solid with 20% hydrochloric acid and stir for 3 h, then dilute and wash the mixed solution with deionized water and filter, the filter cake is dried in a vacuum drying oven at 105 °C for 12 h, then put into a muffle furnace, the heating rate is 5 °C / min, when the temperature reaches 600 °C, calcine in air for 3 h to obtain porous carbon impregnated SiO2support.

[0035] Step 2, preparation of porous carbon impregnated Pt-SiO2

[0036] Take 2 g of porous carbon impregnated SiO2dispersed in 10 mL of deionized water, add 0.3 g of platinum nitrate, mix and stir at room temperature for 12 h, then place in a vacuum drying oven at 105 °C for 12 h to obtain platinum nitrate composite porous carbon impregnated SiO2. Put the above composite into a muffle furnace, the heating rate is 5 °C / min, when the temperature reaches 300 °C, calcine in air for 3 h, cool to room temperature and reduce in H2for 3 h, finally obtain porous carbon impregnated Pt-SiO2.

[0037] Hydrogen production performance of porous carbon doped Pt-SiO2 catalyst for catalytic decomposition of methylcyclohexane

[0038] 0.2 g of the porous carbon doped Pt-SiO2 catalyst was mixed with 3 g of quartz sand, and then placed in a high-pressure catalytic fixed bed. The gas flow rate was 35 mL / min, the pressure was 0.3 MPa, the methylcyclohexane sample injection rate was 0.05 mL / min, and the catalytic reaction temperature was 330°C.

[0039] Comparative Example 1 (in step 1, the coal was not subjected to high-temperature gasification, but was directly calcined and acid-treated to obtain a SiO2 carrier)

[0040] 1 kg of Jurassic coal from northern Shaanxi was ground and sieved to obtain coal with a particle size of 200 mesh. 5 g of the solid was mixed with 20% hydrochloric acid and stirred for 3 h. The mixed solution was then diluted with deionized water, washed, and filtered. The filter cake was dried in a vacuum drying oven at 105°C for 12 h, and then placed in a muffle furnace. The temperature was raised at a rate of 5°C / min, and when the temperature reached 600°C, the sample was calcined in air for 3 h to obtain a SiO2 carrier.

[0041] 2 g of SiO2 was dispersed in 10 mL of deionized water, and 0.3 g of platinum nitrate was added. After stirring at room temperature for 12 h, the mixture was dried in a vacuum drying oven at 105°C for 12 h to obtain a platinum nitrate composite SiO2. The composite was placed in a muffle furnace, and the temperature was raised at a rate of 5°C / min. When the temperature reached 300°C, the sample was calcined in air for 3 h, and then reduced in H2 for 3 h to obtain Pt-SiO2.

[0042] 0.2 g of the Pt-SiO2 catalyst was mixed with 3 g of quartz sand, and then placed in a high-pressure catalytic fixed bed. The gas flow rate was 35 mL / min, the pressure was 0.3 MPa, the methylcyclohexane sample injection rate was 0.05 mL / min, and the catalytic reaction temperature was 330°C.

[0043] Comparative Example 2 (in step 1, the muffle furnace calcination temperature exceeded 600-800°C, and the catalytic performance was poor)

[0044] Take 1kg of Jurassic coal from northern Shaanxi, grind and screen to select 300-mesh coal powder, add 1kg of water and 0.01g of dispersant lignin sulfonate, and stir evenly for 30 minutes to obtain a slurry. The slurry is placed in a micro-entrained bed and air is introduced at a pressure of 3MPa. It is gasified at 1200℃ for 5 minutes, cooled and collected to obtain 0.1kg of solid matter. The collected solid matter is sieved to obtain solid matter with a particle size of less than 200 mesh. 5g of the solid matter is mixed with 20% hydrochloric acid and stirred for 3 hours. The mixed solution is then diluted, washed with deionized water, and filtered. The filter cake is dried in a vacuum drying oven at 105℃ for 12 hours, then placed in a muffle furnace with a heating rate of 5℃ / min. When the temperature reaches 900℃, it is calcined in air for 3 hours to obtain a porous carbon-doped SiO2 carrier.

[0045] 2g of porous carbon-doped SiO2 was dispersed in 10mL of deionized water, and 0.3g of platinum nitrate was added. After stirring at room temperature for 12 hours, the mixture was dried in a vacuum drying oven at 105°C for 12 hours to obtain platinum nitrate-composite porous carbon-doped SiO2. The above composite was placed in a muffle furnace and heated at a rate of 5°C / min. When the temperature reached 300°C, it was calcined in air for 3 hours. After cooling to room temperature, it was reduced under hydrogen for 3 hours to finally obtain porous carbon-doped Pt-SiO2.

[0046] After 0.2 g of porous carbon-doped Pt-SiO2 catalyst and 3 g of quartz sand were mixed evenly, they were placed in a high-pressure catalytic fixed bed with a gas flow rate of 35 mL / min, a pressure of 0.3 MPa, a methylcyclohexane injection rate of 0.05 mL / min, and a catalytic reaction temperature of 330 °C.

[0047] Comparative Example 3 (In step 1, the muffle furnace calcination time exceeds 3-5 hours, and the catalytic performance is poor)

[0048] Take 1kg of Jurassic coal from northern Shaanxi, grind and screen to select 300-mesh coal powder, add 1kg of water and 0.01g of dispersant lignin sulfonate, and stir evenly for 30 minutes to obtain a slurry. The slurry is placed in a micro-entrained bed and air is introduced at a pressure of 3MPa. It is gasified at 1200℃ for 5 minutes, cooled and collected to obtain 0.1kg of solid matter. The collected solid matter is sieved to obtain solid matter with a particle size of less than 200 mesh. 5g of the solid matter is mixed with 20% hydrochloric acid and stirred for 3 hours. The mixed solution is then diluted, washed with deionized water, and filtered. The filter cake is dried in a vacuum drying oven at 105℃ for 12 hours, then placed in a muffle furnace with a heating rate of 5℃ / min. When the temperature reaches 600℃, it is calcined in air for 6 hours to obtain a porous carbon-doped SiO2 carrier.

[0049] Take 2 g of porous carbon mixed with SiO2dispersed in 10 mL of deionized water, add 0.3 g of platinum nitrate, mix and stir at room temperature for 12 h, then place in a vacuum drying oven at 105℃ for 12 h, to obtain platinum nitrate composite porous carbon mixed with SiO2. Put the above composite into a muffle furnace, the heating rate is 5℃ / min, when the temperature reaches 300℃, calcine in air for 3 h, cool to room temperature, then reduce in H2for 3 h, finally obtain porous carbon mixed with Pt-SiO2.

[0050] Put 0.2 g of porous carbon mixed with Pt-SiO2catalyst and 3 g of quartz sand into a high-pressure catalytic fixed bed, the gas flow rate is 35 mL / min, the pressure is 0.3 MPa, the methylcyclohexane sample speed is 0.05 mL / min, and the catalytic reaction temperature is 330℃.

[0051] Comparative example 4 (in experimental step 2, replace platinum nitrate with potassium chloroplatinate, poor catalytic performance)

[0052] Take 1 kg of Shanbei Jurassic coal, grind and sieve the particle size to select 300 mesh coal powder, add 1 kg of water and 0.01 g of dispersant lignosulfonate, uniformly stir for 30 min to obtain a slurry. Put the slurry into a micro-fluidized bed and pass in air, the pressure is 3 MPa, gasify at 1200℃ for 5 min, collect the solid 0.1 kg. Screen the collected solid to obtain solid with particle size less than 200 mesh, mix 5 g of the solid with 20% hydrochloric acid and stir for 3 h, then dilute and wash the mixed solution with deionized water and filter, the filter cake is dried in a vacuum drying oven at 105℃ for 12 h, then put it into a muffle furnace, the heating rate is 5℃ / min, when the temperature reaches 600℃, calcine in air for 3 h, to obtain porous carbon mixed with SiO2support.

[0053] Take 2 g of porous carbon mixed with SiO2dispersed in 10 mL of deionized water, add 0.3 g of potassium chloroplatinate, mix and stir at room temperature for 12 h, then place in a vacuum drying oven at 105℃ for 12 h, to obtain platinum nitrate composite porous carbon mixed with SiO2. Put the above composite into a muffle furnace, the heating rate is 5℃ / min, when the temperature reaches 300℃, calcine in air for 3 h, cool to room temperature, then reduce in H2for 3 h, finally obtain porous carbon mixed with Pt-SiO2.

[0054] Put 0.2 g of porous carbon mixed with Pt-SiO2catalyst and 3 g of quartz sand into a high-pressure catalytic fixed bed, the gas flow rate is 35 mL / min, the pressure is 0.3 MPa, the methylcyclohexane sample speed is 0.05 mL / min, and the catalytic reaction temperature is 330℃.

[0055] Table 1 Comparison of catalytic methylcyclohexane performance of catalysts of example 1 and comparative examples 1-4

[0056]

[0057] Figure 1 SEM test results of the porous carbon-doped SiO2 prepared in the method example 1 of the coal preparation methylcyclohexane dehydrogenation Pt-SiO2 catalyst of the present application are shown in Figure 1 As shown by the SEM test, the obtained porous carbon-doped SiO2 is spherical, and the spherical surface is rich in velvet empty structure. The pore structure is further verified by the BET specific surface area test method, and the pore size is distributed between 1-20 nm.

[0058] Figures 2(a) to 2(c) XPS test results of the porous carbon-doped Pt-SiO2 before and after hydrogen reduction in the method example 1 of the coal preparation methylcyclohexane dehydrogenation Pt-SiO2 catalyst of the present application are shown in Figures 2(a) to 2(c) As shown by the X-ray photoelectron spectroscopy test, the obtained porous carbon-doped Pt-SiO2 mainly contains Si, O, C and Pt elements, and the C content is 2.1% calculated by the high molecular peak area of the X-ray photoelectron spectroscopy. The spectrum of Pt changes greatly before and after reduction, mainly because the Pt4+ is partially reduced to Pt(0).

[0059] Figure 3 EDS chart of Pt in the carbon-doped SiO2 structure in the method example 1 of the coal preparation methylcyclohexane dehydrogenation Pt-SiO2 catalyst of the present application is shown in Figure 3 (a) is the SEM chart, Figure 3 (b) is the Pt EDS chart, Figure 3 (c) is the O EDS chart, Figure 3 (d) is the Si EDS chart, and the EDS test shows that Pt can be well dispersed in the porous carbon-doped Pt-SiO2 carrier, which guarantees the improvement of the subsequent catalyst performance.

[0060] As shown in Figure 4As shown in Table 1, the catalyst in Example 1 catalyzed the dehydrogenation reaction of methylcyclohexane for a long time of 100 h, and the catalyst showed excellent catalytic stability. After 100 h of reaction, the hydrogen overflow concentration reduction rate was only 2.45%. In contrast, the catalytic stability of Comparative Examples 1 and 4 was poor, and the hydrogen overflow concentration reduction was as high as 30%. The possible reason is that the coal in Comparative Example 1 was directly calcined, resulting in the loss of carbon elements, and the catalyst component lacked carbon components; in Comparative Example 4, potassium chloroplatinate was used to prepare the Pt-catalyst, which may have introduced metal element K after reduction, resulting in poor catalyst stability. The conversion rate in Comparative Examples 2 and 3 was greatly reduced, which was due to the fact that the calcination temperature was too high or the calcination time was too long, which would cause the collapse of the pore structure of the catalyst carrier, which was not conducive to the adsorption-desorption of the carrier in the catalytic process of methylcyclohexane.

[0061] Example 2

[0062] Step 1, preparation of porous carbon-doped SiO2

[0063] Take 3 kg of Shanbei Jurassic coal, grind and sieve the particle size to select 400 mesh coal powder, add 5 kg of water and 0.1 g of dispersant lignosulfonate, uniformly stir for 45 min to obtain a slurry. Put the slurry into a micro-fluidized bed and pass in air, the pressure is 4 MPa, gasify at 1400℃ for 30 min, collect the solid 0.3 kg after cooling. Screen the collected solid to obtain solid with particle size less than 200 mesh, mix 8 g of the solid with 24% hydrochloric acid and stir for 4 h, then dilute and wash the mixed solution with deionized water and filter, the filter cake is dried in a vacuum drying box at 120℃ for 12 h, then put it into a muffle furnace, the heating rate is 5℃ / min, when the temperature reaches 700℃, calcine in air for 4 h to obtain a porous carbon-doped SiO2 carrier.

[0064] Step 2, preparation of porous carbon-doped Pt-SiO2

[0065] Take 4 g of porous carbon-doped SiO2 and disperse it in 20 mL of deionized water, add 0.5 g of platinum nitrate, mix and stir at room temperature for 12 h, then place it in a vacuum drying box at 120℃ for 12 h to obtain platinum nitrate composite porous carbon-doped SiO2. Put the above composite into a muffle furnace, the heating rate is 10℃ / min, when the temperature reaches 300℃, calcine in air for 3 h, cool to room temperature and reduce in H2 for 3 h to finally obtain porous carbon-doped Pt-SiO2.

[0066] Performance of porous carbon-doped Pt-SiO2 in catalyzing methylcyclohexane to produce hydrogen

[0067] 0.2 g of porous carbon-doped Pt-SiO2 catalyst was uniformly mixed with 3 g of quartz sand, and then placed in a high-pressure catalytic fixed bed. The gas flow rate was 40 mL / min, the pressure was 0.5 MPa, the methylcyclohexane sample speed was 0.10 mL / min, and the catalytic reaction temperature was 400°C.

[0068] Example 3

[0069] Step 1, preparation of porous carbon-doped SiO2

[0070] 5 kg of Jurassic coal from northern Shaanxi was ground and sieved to obtain 500-mesh coal powder. 10 kg of water and 0.2 g of dispersant lignosulfonate were added and uniformly stirred for 60 min to obtain a slurry. The slurry was placed in a micro-fluidized bed and air was introduced at a pressure of 5 MPa and a temperature of 1500°C for 50 min. The solid material was collected after cooling, and 10 g of the collected solid material was sieved to obtain solid material with a particle size of less than 200 mesh. The 10 g of solid material was mixed with 25% hydrochloric acid and stirred for 5 h. The mixed solution was then diluted with deionized water, washed, and filtered. The filter cake was dried in a vacuum drying oven at 130°C for 12 h, and then placed in a muffle furnace. The temperature was raised at a rate of 5°C / min, and when the temperature reached 800°C, the sample was calcined in air for 5 h to obtain a porous carbon-doped SiO2 carrier.

[0071] Step 2, preparation of porous carbon-doped Pt-SiO2

[0072] 6 g of porous carbon-doped SiO2 was dispersed in 30 mL of deionized water, and 0.9 g of platinum nitrate was added. After mixing and stirring at room temperature for 12 h, the mixture was placed in a vacuum drying oven at 130°C for 12 h to obtain platinum nitrate-complexed porous carbon-doped SiO2. The complex was placed in a muffle furnace, and the temperature was raised at a rate of 15°C / min. When the temperature reached 300°C, the sample was calcined in air for 3 h, and then reduced in H2 for 3 h to obtain porous carbon-doped Pt-SiO2.

[0073] Hydrogen production performance of porous carbon-doped Pt-SiO2 catalyst for methylcyclohexane

[0074] 0.2 g of porous carbon-doped Pt-SiO2 catalyst was uniformly mixed with 3 g of quartz sand, and then placed in a high-pressure catalytic fixed bed. The gas flow rate was 50 mL / min, the pressure was 0.6 MPa, the methylcyclohexane sample speed was 0.15 mL / min, and the catalytic reaction temperature was 410°C.

Claims

1. A process for the preparation of a Pt-SiO2 catalyst for the dehydrogenation of methylcyclohexane, characterized in that: Specifically comprising the following steps: Step 1, porous carbon mixed SiO2 is prepared by using coal; the specific process of step 1 is: Step 1.1, take 1kg-5kg coal, grind and sieve the particle size to select 300-500 mesh coal powder, add 1kg-10kg water and 0.01g-0.2g dispersant lignin sulfonate, stir for 30min-60min, and get slurry; Step 1.2, put the slurry prepared in step 1.1 into the gas flow bed, and pass air into the gas flow bed, the pressure is 3MPa-5MPa, the temperature is 1200 ℃-1500 ℃, and the gasification time is 5min-50min, and then collect the solid 0.1kg-0.5kg after cooling; Step 1.3, sieve the solid collected in step 1.2 to get solid with particle size less than 200 mesh, mix 5g-10g of the solid with 20%-25% hydrochloric acid, stir for 3h-5h, then dilute and wash the mixed solution with deionized water and filter, dry the filter cake in a vacuum drying box at 105 ℃-130 ℃, then put it into a muffle furnace, when the temperature reaches 600 ℃-800 ℃, calcine it in air for 3h-5h, and get porous carbon mixed SiO2 carrier; Step 2, porous carbon mixed Pt-SiO2 is prepared according to the porous carbon mixed SiO2 obtained in step 1.

2. The method of claim 1, wherein the coal preparation methylcyclohexane dehydrogenation Pt-SiO2 catalyst is characterized by: The specific process of step 2 is: Step 2.1, prepare platinum nitrate composite porous carbon mixed SiO2 according to the porous carbon mixed SiO2 obtained in step 1; Step 2.2, put the platinum nitrate composite porous carbon mixed SiO2 prepared in step 2.1 into a muffle furnace, the heating rate is 5 ℃ / min-15 ℃ / min, calcine it in air when the temperature reaches the set temperature, cool it to room temperature, and then reduce it in H2, finally get porous carbon mixed Pt-SiO2.

3. The method of claim 2, wherein the coal preparation methylcyclohexane dehydrogenation Pt-SiO2 catalyst is characterized by: The specific process of step 2.1 is: Disperse 2g-6g porous carbon mixed SiO2 in 10-30 mL deionized water, add 0.3g-0.9g platinum nitrate, mix and stir uniformly at room temperature, and then dry in a vacuum drying box at 105 ℃-130 ℃, to get platinum nitrate composite porous carbon mixed SiO2.

4. A methylcyclohexane dehydrogenation Pt-SiO2 catalyst prepared by the process of any one of claims 1 to 3, characterized in that: The process of using the porous carbon mixed Pt-SiO2 to catalyze the hydrogen production of methylcyclohexane is: Put the porous carbon mixed Pt-SiO2 catalyst and quartz sand into a high-pressure catalytic fixed bed after stirring uniformly, the gas flow rate is 35mL / min-50mL / min, the pressure is 0.3MPa-0.6MPa, the methylcyclohexane sample speed is 0.05mL / min-0.15mL / min, and the catalytic reaction temperature is 330 ℃-410 ℃.

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