High hydrogen content silicone oil low molecular recovery system

Abstract

The application relates to the technical field of silicone production, in particular to a high-hydrogen-containing silicone oil low-molecular recovery system, which comprises hydrogen-containing silicone oil storage tanks, a preheater, an evaporator and a condensing device which are sequentially connected; the top outlet end of the evaporator is connected to the condensing device, and the bottom outlet end is connected to a cooler; the top outlet end of the condensing device is connected to an absorption tower, and the bottom outlet end is connected to a low-molecular tank; the top outlet end of the low-molecular tank is connected to the absorption tower, and the bottom outlet end of the low-molecular tank and the bottom outlet end of the absorption tower are connected to a washing and separating system through a pipeline after being mixed; after hydrogen-containing silicone oil separated by washing and dehydration is introduced into a fixed bed provided with a Pt-Mo / Zr-active white clay catalyst, the hydrogen-containing silicone oil can be recycled, more than 99% of low molecules in the production process of high-hydrogen-containing silicone oil can be recovered, the content of low molecules in the hydrogen-containing silicone oil can be efficiently recovered, and the problems of incomplete hydrolysis and acidification of the reaction system caused in the low-molecular recovery process can be avoided.

Description

Technical Field

[0001] This invention relates to the field of organosilicon production technology, and more specifically, to a low-molecular-weight recovery system for high-hydrogen-content silicone oil. Background Technology

[0002] In existing technologies, high-hydrogen-content silicone oil is generated by hydrolyzing methyldichlorosilane and trimethylchlorosilane. During this process, unpolymerized low-boiling-point compounds need to be removed from the high-hydrogen-content silicone oil at high temperatures under a certain vacuum. These removed low-boiling-point compounds include MH cyclic compounds, small-molecule MH silicone oil, MM silicone oil, chlorinated hydrocarbons, and water. The low-boiling-point compounds collected by condensation at the front end of the vacuum system are called low-boiling-point compounds. Because this portion of low-boiling-point compounds contains many odorous substances and is contaminated by the vacuum system, including Fe, its composition is complex and it is referred to as low-molecular-weight hydrogen-containing silicone oil.

[0003] Currently, only the low-molecular-weight molecules generated during the evaporation process of hydrogen-containing silicone oil are condensed and stored, recovering approximately 70-80% of the low-molecular-weight molecules. The remaining low-molecular-weight molecules enter the vacuum system and pump chamber, forming liquid accumulation. Over time, this accumulation within the vacuum pump chamber, due to the high temperature and acidic substances present during pump operation, causes the low-molecular-weight molecules to react with the acidic substances, forming a gel that clogs the pump chamber. Furthermore, during pump chamber maintenance, leaks, and damage, air can easily enter, potentially causing flash fires and explosions within the pump chamber. CN103788377B, a continuous production process for high-hydrogen-content silicone oil, and CN217103658U, a low-molecular-weight recovery system for high-hydrogen-content silicone oil, both propose recycling to a hydrolysis reaction system. While this can improve the recovery rate to some extent, recycling low-molecular-weight molecules to the reaction system also reduces the efficiency of the hydrolysis reaction of methyldichlorosilane and trimethylchlorosilane, resulting in incomplete hydrolysis and causing acid reversion in the hydrogen-containing silicone oil product after a certain period of storage. Summary of the Invention

[0004] The purpose of this invention is to provide a low-molecular-weight recovery system for high-hydrogen-content silicone oil, which can recover more than 99% of the low-molecular-weight components in the production process of high-hydrogen-content silicone oil, achieve efficient recovery of the low-molecular-weight content in hydrogen-containing silicone oil, and avoid incomplete hydrolysis and acid backflow problems in the reaction system caused by the low-molecular-weight recovery process.

[0005] The embodiments of the present invention are achieved through the following technical solutions:

[0006] A high-hydrogen-content silicone oil low-molecular-weight recovery system includes a hydrogen-content silicone oil storage tank, a preheater, an evaporator, and a condenser connected in sequence.

[0007] The top outlet of the evaporator is connected to the condenser, and the bottom outlet is connected to the cooler.

[0008] The top outlet of the condensation device is connected to the absorption tower, and the bottom outlet is connected to the low molecular weight tank.

[0009] The top outlet of the low molecular weight tank is connected to the absorption tower, and the bottom outlet of the low molecular weight tank and the bottom outlet of the absorption tower are connected to the washing and separation system after being mixed by a pipeline.

[0010] The hydrogen-containing silicone oil, after washing and dehydration, can be recycled by passing it through a fixed bed containing a Pt-Mo / Zr-activated clay catalyst.

[0011] The technical solutions of the embodiments of the present invention have at least the following advantages and beneficial effects:

[0012] The recycling system of this invention can efficiently recover the low molecular weight content in hydrogen-containing silicone oil, especially the low molecular weight that has not been condensed by the condenser. At the same time, the high activity and polymerization capacity of the Pt-Mo / Zr-activated clay catalyst in the fixed bed can readjust and polymerize the low molecular weight material of the hydrogen-containing silicone oil. After the fixed bed adjustment and polymerization, the low molecular weight content in the hydrogen-containing silicone oil can be reduced to less than 1% of the hydrogen-containing silicone oil feed. It can recover more than 99% of the low molecular weight in the high hydrogen-containing silicone oil production process, thus achieving efficient recovery of the low molecular weight content in hydrogen-containing silicone oil. Attached Figure Description

[0013] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0014] Figure 1 The flowchart is for the high hydrogen content silicone oil low molecular weight recovery system provided in Embodiment 1 of the present invention. Detailed Implementation

[0015] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0016] The following is a detailed description of a high-hydrogen-content silicone oil low-molecular-weight recovery system provided by an embodiment of the present invention.

[0017] A high-hydrogen-content silicone oil low-molecular-weight recovery system includes a hydrogen-content silicone oil storage tank, a preheater, an evaporator, and a condenser connected in sequence.

[0018] The top outlet of the evaporator is connected to the condenser, and the bottom outlet is connected to the cooler; the top outlet of the condenser is connected to the absorption tower, and the bottom outlet is connected to the low molecular weight tank; the top outlet of the low molecular weight tank is connected to the absorption tower, and the bottom outlet of the low molecular weight tank and the bottom outlet of the absorption tower are connected to the washing and separation system after being mixed by a pipeline; the hydrogen-containing silicone oil after washing and dehydration separation can be recycled by passing it into a fixed bed containing a catalyst.

[0019] Furthermore, the condensation device includes at least one condenser, and the bottom outlets of multiple condensers are connected to a low molecular weight tank via pipes.

[0020] Furthermore, the low molecular weight tank and the evaporator are at the same pressure and both are under negative pressure.

[0021] Furthermore, the top outlet of the low molecular weight tank is connected to the absorption tower via a vacuum pipeline.

[0022] Furthermore, the bottom outlet of the condensation device is higher than the inlet of the low molecular weight tank connected to it.

[0023] Furthermore, the cooler includes a primary cooler and a secondary cooler. After being cooled by the primary cooler, the bottom outlet of the evaporator is sent to the absorption tower and the refining system through pipelines. The secondary cooler is also installed on the pipeline between the primary cooler and the absorption tower.

[0024] Furthermore, the hydrogen-containing silicone oil low-molecular-weight material after being processed by the fixed bed is filtered and then enters the hydrogen-containing silicone oil storage tank.

[0025] Furthermore, at least one fixed bed is provided, and a filter is connected to the fixed bed.

[0026] The intermediate product of hydrogen-containing silicone oil is fed from the hydrogen-containing silicone oil storage tank into the preheater through a de-feeding pump. Specifically, the temperature of the preheater is controlled at 140-150℃. Then, it enters the evaporator for distillation. The evaporator is heated by steam or heat transfer oil and the temperature is controlled at 155-160℃. The evaporator pressure is controlled by the vacuum system at -90KPa.

[0027] The top of the evaporator is connected to the inlet of the first-stage condenser, the top outlet of the first-stage condenser is connected to the inlet of the second-stage condenser, and the bottom outlet of the first-stage condenser is connected to a low-molecular-weight tank that is evacuated to the same negative pressure as the evaporator by the vacuum system. The hydrogen-containing silicone oil low-molecular-weight is discharged into the low-molecular-weight tank that is evacuated to the same negative pressure as the evaporator by the vacuum system through the height difference (the height difference refers to the ratio of the bottom outlet of the low-molecular-weight condenser to the inlet of the low-molecular-weight tank). Then, it is pumped to the washing and separation system.

[0028] In this process, the low-molecular-weight materials exiting from the top of the evaporator are condensed by the primary and secondary condensers, recovering approximately 70-80% of the low-molecular-weight materials. The remaining 20-30% of the uncondensed hydrogen-containing silicone oil low-molecular-weight materials will enter the circulating absorption tower in gaseous form (the circulating material in this absorption tower comes from the bottom of the evaporator and is cooled to below 40°C by the outlet cooler). The evaporated hydrogen-containing silicone oil low-molecular-weight materials are fully absorbed by the low-temperature, high-hydrogen-content silicone oil in the absorption tower, ultimately resulting in almost complete recovery of the low-molecular-weight materials. This invention's processing system performs deep recovery treatment on the low-molecular-weight materials that were not condensed by the condenser, greatly improving the recovery rate.

[0029] The hydrogen-containing silicone oil is cooled to below 60°C by a primary cooler from the bottom outlet of the evaporator, and then cooled to below 40°C by a secondary cooler (the primary cooler uses industrial circulating water for cooling, and the secondary cooler uses industrial chilled brine at -15°C for cooling). After cooling, the hydrogen-containing silicone oil enters the absorption tower and the refining system respectively.

[0030] After the material is fully absorbed in the absorption tower and mixed with the low-molecular-weight material in the low-molecular-weight tank, it is pumped to the washing and separation system and washed with hot water at 50-60℃. Then, it undergoes stratified dehydration. The hydrogen-containing silicone oil after hot water washing and dehydration is then passed into a fixed bed containing a Pt-Mo / Zr-activated clay catalyst. It is necessary to ensure that the material passes through the fixed bed for a continuous residence time of 2 hours or more. (In this embodiment, there are two fixed beds, A and B, for switching between them. The inventors found that after a period of use, the fixed bed...) Moisture can accumulate, easily leading to catalyst deactivation. Therefore, this invention uses nitrogen to blow the unused material in the fixed bed into the intermediate tank containing hydrogen-silicone oil, ensuring the duration is sufficient to guarantee the polymerization reaction achieves the desired effect. The low-molecular-weight material of the hydrogen-silicone oil is then re-polymerized and passed through a high-precision filter (in this embodiment, a 1-micron bag filter is used to remove impurities from the hydrogen-silicone oil) before entering the intermediate tank. The intermediate product of the hydrogen-silicone oil is then sent to the preheater by a de-lowering feed pump for recycling.

[0031] Furthermore, the preparation method of the Pt-Mo / Zr-activated clay catalyst is as follows:

[0032] (1) Add sodium carbonate and hydrogen peroxide to the aqueous solution of activated clay to adjust it into a slurry, disperse it evenly, and obtain solution A; wherein, the mass ratio of activated clay, sodium carbonate and hydrogen peroxide is 10-20:3-5:1;

[0033] (2) Mix the salt solutions of molybdenum nitrate and zirconium nitrate in a 1:1 mass ratio, add an appropriate amount of alkaline solution and mix well to obtain solution B;

[0034] (3) Mix solution A and solution B at a volume ratio of 3-5:1, add platinum chloride, let stand for 2-5 hours, dry at 120-160℃ for 0.5-1.5 hours, and calcine at 250-400℃ for 2-4 hours to obtain the Pt-Mo / Zr-activated clay catalyst.

[0035] Activated clay possesses strong adsorption and purification capabilities, exhibiting exceptional adsorption of pigments and impurities while maintaining high stability. This invention loads platinum onto activated clay, enhancing its catalytic activity and stability. To improve dispersion stability, Mo / Zr is blended with activated clay, and pre-treatment with sodium carbonate solution rapidly yields a hierarchical porous catalyst containing micropores and mesopores at lower alkaline concentrations, significantly increasing the platinum loading rate. More importantly, this invention loads molybdenum nitrate and zirconium nitrate onto the treated activated clay surface. The increased acid-base sites on the treated surface promote the stability of platinum loading, further enhancing catalytic activity and catalyst stability. The hydrogen-containing silicone oil low-molecular-weight material is re-polymerized, generating more hydroxyl groups and moderate to strong Lewis acid sites, strengthening the interaction with the support. Furthermore, the larger catalyst surface area facilitates the formation of smaller nanoparticles from the loaded metal, improving the catalyst's reactivity and polymerization capacity.

[0036] The recovery system and processing method of this invention preheats and evaporates hydrogen-containing silicone oil, then condenses it. Simultaneously, low-molecular-weight molecules that are not condensed are absorbed. Specifically, the evaporated low-molecular-weight hydrogen-containing silicone oil is fully absorbed by the low-temperature, high-hydrogen-content silicone oil (the low-molecular-weight molecules that were not condensed) in the absorption tower, and then mixed with the condensed low-molecular-weight molecules for washing, separation, and catalytic adjustment polymerization. This avoids the reduced efficiency and incomplete hydrolysis of methyldichlorosilane and trimethylchlorosilane caused by the recovery of low-molecular-weight molecules into the reaction system, which could lead to acid reversion in the hydrogen-containing silicone oil product. It improves the recovery rate while ensuring the stability and safety of the reaction system. Multiple laboratory sampling analyses confirm this. The components entering the intermediate tank of hydrogen-containing silicone oil contain 5-10% low molecular weight. Taking the amount of hydrogen-containing silicone oil entering the preheater as 1 ton / hour, the output from the bottom of the evaporator is 1*(1-10%) = 0.9 tons / hour, the output to the refining system is 0.8 tons / hour, and the output to the absorption tower is 0.1 tons / hour. The total amount of hydrogen-containing silicone oil going to the fixed bed after absorption is 0.1+0.1=0.2 tons / hour. The low molecular weight content in the hydrogen-containing silicone oil after fixed bed polymerization is less than 1% of the hydrogen-containing silicone oil feed ((1-0.8)*5%=1%). It can recover more than 99% of the low molecular weight in the high hydrogen-containing silicone oil production process. The unrecovered low molecular weight is drawn to the pump head by the vacuum system and then enters the tail gas treatment system.

[0037] Example 1

[0038] A high-hydrogen-content silicone oil low-molecular-weight recovery system includes a hydrogen-content silicone oil storage tank, a preheater, an evaporator, a primary condenser, and a secondary condenser connected in sequence; wherein, the preheater temperature is 145℃, the evaporator temperature is 155℃, and the evaporator pressure is -90KPa.

[0039] The top outlet of the evaporator is connected in sequence to the primary condenser and the secondary condenser, and the bottom outlet is connected in sequence to the primary cooler, the secondary condenser and the absorption tower; the primary cooler cools the hydrogen-containing silicone oil to below 60°C, and the secondary cooler cools the hydrogen-containing silicone oil to below 40°C.

[0040] The top outlet of the secondary condenser is connected to the absorption tower, and the absorption tower is evacuated by a vacuum system. The bottom outlets of the primary condenser and the secondary condenser are connected to the low molecular weight tank.

[0041] The top outlet of the low molecular weight vessel is connected to the absorption tower via a vacuum pipeline. The bottom outlet of the low molecular weight vessel and the bottom outlet of the absorption tower are mixed through a pipeline and then connected to the washing and separation system. The vessel is washed with hot water at 60°C and then dehydrated in layers. The hydrogen-containing silicone oil after washing and dehydration is passed into fixed beds A and B containing Pt-Mo / Zr-activated clay catalyst. The material is kept in the fixed beds for at least 2 hours. After filtration, the material enters the intermediate hydrogen-containing silicone oil tank. The intermediate hydrogen-containing silicone oil is then sent to the preheater by a dehydration feed pump for recycling.

[0042] The preparation method of the Pt-Mo / Zr-activated clay catalyst is as follows:

[0043] (1) Add sodium carbonate and hydrogen peroxide to the aqueous solution of activated clay to adjust it into a slurry, disperse it evenly, and obtain solution A; wherein, the mass ratio of activated clay, sodium carbonate and hydrogen peroxide is 15:4:1.

[0044] (2) Mix the salt solutions of molybdenum nitrate and zirconium nitrate in a 1:1 mass ratio, then add sodium carbonate solution with a mass of 1 / 10 of molybdenum nitrate and mix well to obtain solution B;

[0045] (3) Mix solution A and solution B in a volume ratio of 4:1, add platinum chloride, let stand for 3 hours, dry at 140°C for 1 hour, and calcine at 350°C for 3 hours to obtain the Pt-Mo / Zr-activated clay catalyst.

[0046] Through the recovery system and processing method of this embodiment, the analysis of the components entering the intermediate tank of hydrogen-containing silicone oil by laboratory sampling shows that 10% of the components are low molecular weight. Taking the amount of hydrogen-containing silicone oil entering the preheater as 1 ton / hour, the amount of material discharged from the bottom of the evaporator is 1*(1-10%) = 0.9 tons / hour, the amount going to the refining system is 0.8 tons / hour, and the amount going to the absorption tower is 0.1 tons / hour. The total amount of hydrogen-containing silicone oil going to the fixed bed after absorption is 0.1+0.1=0.2 tons / hour. The low molecular weight content in the hydrogen-containing silicone oil after fixed bed polymerization accounts for only 1% of the hydrogen-containing silicone oil feed ((1-0.8)*5%=1%). It can recover more than 99% of the low molecular weight in the high hydrogen-containing silicone oil production process. The unrecovered low molecular weight is drawn to the pump head by the vacuum system and then enters the tail gas treatment system.

[0047] Example 2

[0048] The difference between this embodiment and Embodiment 1 is that:

[0049] The preparation method of Pt-Mo / Zr-activated clay catalyst is as follows:

[0050] (1) Add sodium carbonate and hydrogen peroxide to the aqueous solution of activated clay to adjust it into a slurry, disperse it evenly, and obtain solution A; wherein the mass ratio of activated clay, sodium carbonate and hydrogen peroxide is 15:3:1.

[0051] (2) Mix the salt solutions of molybdenum nitrate and zirconium nitrate in a 1:1 mass ratio, then add sodium carbonate solution with a mass of 1 / 10 of molybdenum nitrate and mix well to obtain solution B;

[0052] (3) Mix solution A and solution B in a volume ratio of 3:1, add platinum chloride, let stand for 3 hours, dry at 130°C for 0.5 hours, and calcine at 300°C for 3 hours to obtain the Pt-Mo / Zr-activated clay catalyst.

[0053] Sampling analysis: The low molecular weight content of hydrogen-containing silicone oil after treatment with a fixed bed containing Pt-Mo / Zr-activated clay catalyst accounts for only 0.4% of the hydrogen-containing silicone oil feed, which can recover more than 99% of the low molecular weight in the production process of high hydrogen-containing silicone oil.

[0054] Example 3

[0055] The difference between this embodiment and Embodiment 1 is that:

[0056] The preparation method of Pt-Mo / Zr-activated clay catalyst is as follows:

[0057] (1) Add sodium carbonate and hydrogen peroxide to the aqueous solution of activated clay to adjust it into a slurry, disperse it evenly, and obtain solution A; wherein the mass ratio of activated clay, sodium carbonate and hydrogen peroxide is 20:5:1.

[0058] (2) Mix the salt solutions of molybdenum nitrate and zirconium nitrate in a 1:1 mass ratio, then add sodium carbonate solution with a mass of 1 / 10 of molybdenum nitrate and mix well to obtain solution B;

[0059] (3) Mix solution A and solution B at a volume ratio of 5:1, add platinum chloride, let stand for 3 hours, dry at 150°C for 1 hour, and calcine at 380°C for 2 hours to obtain the Pt-Mo / Zr-activated clay catalyst.

[0060] Sampling analysis: The low molecular weight content of hydrogen-containing silicone oil after treatment with a fixed bed containing Pt-Mo / Zr-activated clay catalyst accounts for only 0.5% of the hydrogen-containing silicone oil feed, which can recover more than 99% of the low molecular weight in the production process of high hydrogen-containing silicone oil.

[0061] Comparative Example 1

[0062] The difference between this comparative example and Example 1 is that the catalyst is an activated clay catalyst.

[0063] Sampling analysis: The low molecular weight content of the hydrogen-containing silicone oil after fixed-bed treatment with activated clay catalyst accounted for 4.3% of the hydrogen-containing silicone oil feed.

[0064] Therefore, the recycling system of this invention can efficiently recover the low molecular weight content in hydrogen-containing silicone oil, especially the low molecular weight that has not been condensed by the condenser. At the same time, the high activity and polymerization capacity of the Pt-Mo / Zr-activated clay catalyst in the fixed bed can readjust and polymerize the low molecular weight material of the hydrogen-containing silicone oil. This reduces the low molecular weight content of the hydrogen-containing silicone oil after fixed-bed adjustment and polymerization to less than 1% of the hydrogen-containing silicone oil feed. It can recover more than 99% of the low molecular weight in the high hydrogen-containing silicone oil production process, achieving efficient recovery of the low molecular weight content in hydrogen-containing silicone oil.

[0065] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A low-molecular-weight recovery system for high-hydrogen-content silicone oil, characterized in that: It includes a hydrogen-containing silicone oil storage tank, a preheater, an evaporator, and a condenser connected in sequence; The top outlet of the evaporator is connected to the condenser, and the bottom outlet is connected to the cooler. The hydrogen-containing silicone oil is cooled by the cooler from the bottom outlet of the evaporator and then enters the absorption tower and the refining system respectively. The top outlet of the condensation device is connected to the absorption tower, and the bottom outlet is connected to the low molecular weight tank. The top outlet of the low molecular weight tank is connected to the absorption tower, and the bottom outlet of the low molecular weight tank and the bottom outlet of the absorption tower are connected to the washing and separation system after being mixed by a pipeline. The hydrogen-containing silicone oil, after washing and dehydration, can be recycled by passing it through a fixed bed containing a catalyst.

2. The high-hydrogen-content silicone oil low-molecular-weight recovery system according to claim 1, characterized in that, The condensation device includes at least one condenser, and the bottom outlets of multiple condensers are connected to a low molecular weight tank via pipes.

3. The high-hydrogen-content silicone oil low-molecular-weight recovery system according to claim 1, characterized in that, The low molecular weight tank and the evaporator are at the same pressure and both are under negative pressure.

4. The high-hydrogen-content silicone oil low-molecular-weight recovery system according to claim 1, characterized in that, The top outlet of the low molecular weight tank is connected to the absorption tower via a vacuum pipeline.

5. The high-hydrogen-content silicone oil low-molecular-weight recovery system according to claim 1, characterized in that, The bottom outlet of the condensation device is higher than the inlet of the low molecular weight tank connected to it.

6. The high-hydrogen-content silicone oil low-molecular-weight recovery system according to claim 1, characterized in that, The cooler includes a primary cooler and a secondary cooler. After being cooled by the primary cooler, the bottom outlet of the evaporator is sent to the absorption tower and the refining system through pipelines. The secondary cooler is also installed on the pipeline between the primary cooler and the absorption tower.

7. The high-hydrogen-content silicone oil low-molecular-weight recovery system according to claim 1, characterized in that, After being processed by a fixed bed, the low-molecular-weight hydrogen-containing silicone oil is filtered and then enters the hydrogen-containing silicone oil storage tank.

8. The high-hydrogen-content silicone oil low-molecular-weight recovery system according to claim 7, characterized in that, At least one fixed bed is provided, and one fixed bed is connected to a filter.

9. The high-hydrogen-content silicone oil low-molecular-weight recovery system according to claim 1, characterized in that, The catalyst is Pt-Mo / Zr-activated clay.

10. The high-hydrogen-content silicone oil low-molecular-weight recovery system according to claim 9, characterized in that, The catalyst is prepared by: (1) Add sodium carbonate and hydrogen peroxide to the aqueous solution of activated clay to adjust it into a slurry, disperse it evenly, and obtain solution A; (2) After mixing the salt solutions of molybdenum nitrate and zirconium nitrate, add an appropriate amount of alkaline solution and mix well to obtain solution B; (3) After mixing solution A and solution B, add platinum chloride, let stand for a period of time, and then dry and calcine to obtain the Pt-Mo / Zr-activated clay catalyst.

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