Low-mercury catalyst with slow catalytic activity attenuation and preparation method thereof
By replacing part of the mercuric chloride with stannous chloride, barium chloride, calcium chloride, and yttrium chloride in the low-mercury catalyst, and using high-strength, high-specific-surface-area activated carbon as a carrier, the problem of rapid catalytic activity decay in low-mercury catalysts has been solved, achieving high-efficiency catalytic performance and low mercury loss, and extending service life.
Patent Information
- Application Number
- CN202511108040.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-07
- Publication Date
- 2025-11-07
AI Technical Summary
The catalytic activity of existing low-mercury catalysts decays rapidly. How can we prepare a low-mercury catalyst with slow catalytic activity decay to improve its service life and reduce mercury loss?
Stannous chloride, barium chloride, calcium chloride, and yttrium chloride were used to replace part of the mercuric chloride, and activated carbon with high mechanical strength and large specific surface area was used as a carrier. The low mercury catalyst was prepared through steps such as acid leaching, crushing, and carbonization of fruit shells to form a porous structure to fix the chloride salts and reduce dispersion.
The activity retention rate of the low-mercury catalyst reached 96.7%, and the mercuric chloride loss rate was as low as 0.12%, which extended the service life and reduced the production cost.
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Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of catalyst, in particular to a low-mercury catalyst with slow catalytic activity decay and a preparation method thereof. BACKGROUND
[0002] Currently, the catalyst commonly used for the addition reaction of hydrogen chloride gas and acetylene gas to synthesize chloroethylene is mercury catalyst. For example, a related patent discloses a mercuric chloride low-mercury catalyst and a preparation method thereof, which uses activated carbon as a carrier to adsorb mercuric chloride. However, the content of mercuric chloride in the catalyst formula is 8.0-10.0%, which is relatively high. Studies have shown that in the practical application of high-mercury catalyst, it is found that the loss rate of mercuric chloride is very fast in the initial stage. When the mass fraction of mercuric chloride stabilizes at about 9%, the loss rate of mercuric chloride slows down. The mass fraction of mercuric chloride is relatively stable at 5-8% and the utilization rate is high. Therefore, low-mercury catalyst is the main direction of the current research on mercury catalyst. For example, a related patent discloses a low-mercury catalyst for synthesizing polyvinyl chloride and a preparation method thereof, which uses the addition of barium chloride, rare earth chloride, cadmium chloride, and nickel chloride to replace mercuric chloride to prepare a low-mercury catalyst. The content of mercuric chloride is reduced from the traditional 10-12% to 4-6.5%. The obtained low-mercury catalyst meets the national low-mercury catalyst requirements, and the catalytic use effect is equivalent to that of traditional high-mercury catalyst. Although this method can reduce the content of mercury in the mercury catalyst, the catalytic time is relatively short, and the content of mercuric chloride in the deactivated mercury catalyst is 0.16-1.5%, and the activity of the mercury catalyst decays quickly.
[0003] Therefore, how to prepare a low-mercury catalyst with slow catalytic activity decay is a technical problem to be solved in the art. SUMMARY
[0004] The present application aims to provide a low-mercury catalyst with slow catalytic activity decay and a preparation method thereof.
[0005] In order to achieve the above-mentioned application purposes, the present application provides the following technical solutions:
[0006] The present application provides a low-mercury catalyst with slow catalytic activity decay, which comprises, by mass percentage, 1-2% of mercuric chloride, 0.2-2% of stannous chloride, 0.1-0.5% of barium chloride, 0.1-0.5% of calcium chloride, 0.2-0.3% of yttrium chloride, and the balance of activated carbon; the strength of the activated carbon is ≥96%, the mesopore rate of the activated carbon is 70-90%, and the specific surface area of the activated carbon is ≥3200 m 2 / g.
[0007] The present application also provides a preparation method of the low-mercury catalyst with slow catalytic activity decay, comprising the following steps:
[0008] (1) sequentially subjecting shells to acid immersion and crushing to obtain biomass powder;
[0009] (2) mixing the biomass powder obtained in step (1) with a binder, an activator and water to obtain a mixed slurry;
[0010] (3) sequentially performing molding, carbonization, acidification and water washing on the mixed slurry obtained in step (2) to obtain activated carbon;
[0011] (4) mixing mercury chloride, stannous chloride, barium chloride, calcium chloride and yttrium chloride with water to obtain an impregnation solution;
[0012] (5) immersing the activated carbon obtained in step (3) in the impregnation solution obtained in step (4) to obtain a low-mercury catalyst.
[0013] Preferably, the shell in step (1) comprises one or more of peanut shell, coconut shell and walnut shell.
[0014] Preferably, the acid solution used in the acid leaching in step (1) comprises one or more of phosphoric acid, sulfuric acid and boric acid.
[0015] Preferably, the binder in step (2) comprises one or more of starch, polyvinyl alcohol and sodium carboxymethyl cellulose.
[0016] Preferably, the mass of the binder accounts for 1-15% of the mass of the biomass powder.
[0017] Preferably, the activator in step (2) comprises phosphoric acid or zinc oxide.
[0018] Preferably, the mass of the activator accounts for 1-10% of the mass of the biomass powder.
[0019] Preferably, the carbonization temperature in step (3) is 350-800℃, and the carbonization time is 2-6h.
[0020] Preferably, the impregnation temperature in step (5) is 80-90℃, and the impregnation time is 3-6h.
[0021] The present application provides a low-mercury catalyst with slow catalytic activity decay, which comprises, by mass percentage, 1-2% of mercury chloride, 0.2-2% of stannous chloride, 0.1-0.5% of barium chloride, 0.1-0.5% of calcium chloride, 0.2-0.3% of yttrium chloride and the balance of activated carbon; the strength of the activated carbon is ≥96%, the mesopore ratio of the activated carbon is 70-90%, and the specific surface area of the activated carbon is ≥3200m 2 / g. This invention utilizes stannous chloride, barium chloride, calcium chloride, and yttrium chloride to replace part of the mercuric chloride, thereby reducing the amount of mercuric chloride in the catalyst while ensuring catalytic performance, thus lowering the production cost and mercury loss. The invention uses activated carbon with a large specific surface area, high mechanical properties, and high porosity as a carrier, which is more conducive to the fixation of mercury and other chloride salts in the pores, reducing mercury attenuation. Furthermore, it can reduce dispersion and loosening of the catalyst during use, thereby improving the service life of the low-mercury catalyst. Example results show that the low-mercury catalyst provided by this invention maintains an activity retention rate of 96.7% after 8000 hours of use, with no significant breakage; the mercuric chloride loss rate is as low as 0.12%. Detailed Implementation
[0022] This invention provides a low-mercury catalyst with slow catalytic activity decay, comprising, by mass percentage: 1-2% mercuric chloride, 0.2-2% stannous chloride, 0.1-0.5% barium chloride, 0.1-0.5% calcium chloride, 0.2-0.3% yttrium chloride, and the balance activated carbon; wherein the activated carbon has a strength ≥96%, a mesoporous content of 70-90%, and a specific surface area ≥3200 m². 2 / g.
[0023] Unless otherwise specified, all reagents used in this invention are commercially available products.
[0024] The low-mercury catalyst with slow catalytic activity decay provided by the present invention comprises 1-2% mercuric chloride, preferably 1-1.5%, by mass percentage. The present invention utilizes mercuric chloride as the active component of the low-mercury catalyst.
[0025] The low-mercury catalyst with slow catalytic activity decay provided by this invention comprises 0.2-2% stannous chloride, preferably 0.5-1%, by weight percentage. This invention uses stannous chloride to replace a portion of mercuric chloride, enabling its use in catalyzing the hydrochlorination of acetylene to produce vinyl chloride.
[0026] The low-mercury catalyst with slow catalytic activity decay provided by the present invention comprises 0.1-0.5% barium chloride, preferably 0.2-0.4%, by mass percentage. The addition of barium chloride to the low-mercury catalyst in the present invention can act as a chloride salt stabilizer.
[0027] The low-mercury catalyst with slow catalytic activity decay provided by the present invention comprises 0.1-0.5% calcium chloride, preferably 0.2-0.4%, by mass percentage.
[0028] The low-mercury catalyst with slow catalytic activity decay provided by this invention comprises 0.2-0.3% yttrium chloride, preferably 0.25-0.3%, by weight percentage. This invention reduces the amount of mercury chloride in the catalyst while ensuring catalytic performance by replacing part of the mercury chloride with calcium chloride and yttrium chloride.
[0029] The low-mercury catalyst with slow catalytic activity decay provided by the application comprises the balance of activated carbon in percentage by mass. In the application, the strength of the activated carbon is ≥96%, preferably ≥99%; the mesopore ratio of the activated carbon is 70-90%, preferably 80-90%; and the specific surface area of the activated carbon is preferably ≥3200 m 2 / g, preferably 3200-3800 m 2 / g. The use of the activated carbon of the above type in the application has high mechanical strength, large mesopore ratio and specific surface area, and the use of the activated carbon as a carrier is more conducive to the fixation of mercury and other chlorinated salts in the pores, reduces the decay of mercury, and also reduces the dispersion and relaxation of the catalyst during use, thereby improving the service life of the low-mercury catalyst.
[0030] The application provides a preparation method of a low-mercury catalyst with slow catalytic activity decay, comprising the following steps:
[0031] (1) sequentially subjecting a shell to acid immersion and crushing to obtain a biomass powder;
[0032] (2) mixing the biomass powder obtained in the step (1) with a binder, an activator and water to obtain a mixed slurry;
[0033] (3) sequentially subjecting the mixed slurry obtained in the step (2) to shaping, carbonization, acidification and water washing to obtain activated carbon;
[0034] (4) mixing mercury chloride, stannous chloride, barium chloride, calcium chloride and yttrium chloride with water to obtain an impregnation solution;
[0035] (5) subjecting the activated carbon obtained in the step (3) to impregnation in the impregnation solution obtained in the step (4) to obtain a low-mercury catalyst.
[0036] The application sequentially subjects a shell to acid immersion and crushing to obtain a biomass powder.
[0037] In the application, the shell preferably comprises one or more of peanut shell, coconut shell and walnut shell, and more preferably walnut shell and / or coconut shell. The use of the shell as a raw material in the application is more conducive to obtaining hard activated carbon.
[0038] In the present application, the acid solution used in the acid leaching preferably comprises one or more of phosphoric acid, sulfuric acid and boric acid, and more preferably is phosphoric acid. In the present application, the mass concentration of the acid solution is preferably 5-10 wt%, and more preferably 6-8 wt%. By using the acid solution described above to leach the fruit shells, the present application can remove the acid-soluble impurities in the fruit shells, and also open the pores in the fruit shells to increase the specific surface area and micropore size of the activated carbon. The acid treatment can also increase the number of hydroxyl and hydrogen groups on the surface of the activated carbon, and the introduction of these functional groups can enhance the stability of the surface of the activated carbon and prevent it from being excessively lost.
[0039] The present application does not have special limitations on the amount of acid solution used in the acid leaching, and the fruit shells can be completely immersed in the acid solution.
[0040] In the present application, the temperature of the acid leaching is preferably room temperature, and the time of the acid leaching is preferably 3-6 h, and more preferably 5-6 h. The present application can sufficiently remove impurities from the fruit shells and sufficiently open the pores in the fruit shells under the above-mentioned parameters of the acid leaching.
[0041] The present application preferably sequentially performs filtering, washing and drying after the acid leaching to obtain dried acid-treated fruit shells. The present application does not have special limitations on the operation method of the filtering, washing and drying, and a conventional experimental method can be used. In the present application, the drying temperature is preferably 80-120℃, and more preferably 100-110℃; and the drying time is preferably 1-3 h, and more preferably 2-3 h. The present application can sufficiently remove the residual acid solution in the acid-treated fruit shells by filtering, washing and drying.
[0042] The present application does not have special limitations on the method of crushing, and a conventional crushing method can be used.
[0043] The present application preferably performs screening on the powder obtained by crushing to obtain a biomass powder. In the present application, the particle size of the biomass powder is preferably 100-300 mesh, and more preferably 200-300 mesh. The present application does not have special limitations on the method of screening, and a conventional screening method can be used to make the particle size of the biomass powder reach the above-mentioned range.
[0044] After obtaining the biomass powder, the present application mixes the biomass powder with a binder, an activator and water to obtain a mixed slurry.
[0045] In the present application, the binder preferably comprises one or more of starch, polyvinyl alcohol and sodium carboxymethyl cellulose, and more preferably is starch and / or sodium carboxymethyl cellulose. By adding the binder, the present application can bond the biomass powder and increase the mechanical strength of the activated carbon after carbonization.
[0046] In the present application, the mass of the binder preferably accounts for 1-15% of the mass of the biomass powder, more preferably 5-10%. The present application is more conducive to fully binding the biomass powder by controlling the amount of the binder within the above range.
[0047] In the present application, the activator preferably includes phosphoric acid or zinc oxide, and the concentration of the phosphoric acid is preferably ≥ 85 wt.%. The present application is capable of forming abundant pore structures inside the activated carbon during carbonization by adding the activator.
[0048] In the present application, the mass of the activator preferably accounts for 1-10% of the mass of the biomass powder, more preferably 5-8%. The present application is more conducive to increasing the specific surface area of the activated carbon by controlling the amount of the activator within the above range.
[0049] The present application does not have a special limitation on the amount of water, which can be adjusted according to the amounts of the biomass powder, the binder and the activator, so that the obtained mixed slurry is more easily extruded.
[0050] The present application does not have a special limitation on the method of mixing the biomass powder, the binder, the activator and water, which can be mixed uniformly by using a conventional mixing method. In the present application, the method of mixing the biomass powder, the binder, the activator and water preferably includes stirring, and the stirring is preferably performed at a temperature of 30-50°C for 1-4h, more preferably 2-3h.
[0051] After obtaining the mixed slurry, the present application successively performs molding, carbonization, acidification and water washing on the mixed slurry to obtain activated carbon.
[0052] The present application does not have a special limitation on the method of molding, which can be performed by using a conventional molding method. In the present application, the method of molding preferably includes extruding the mixed slurry into a billet and then drying the billet. In the present application, the billet is preferably cylindrical, and the diameter and length of the cylindrical billet are not specially limited, which can be adjusted as needed. In the present application, the drying is preferably performed at a temperature of 100-130°C, more preferably 120-130°C, for 1-3h, more preferably 2-3h.
[0053] In the present application, the carbonization is preferably performed at a temperature of 350-800°C, more preferably 400-700°C, for 2-6h, more preferably 5-6h. The present application preferably adopts programmed temperature rising during carbonization, and the temperature rising rate from room temperature to the carbonization temperature is preferably 1-5°C / min, more preferably 1-3°C / min. The present application is more conducive to fully carbonizing the biomass and forming a porous structure by using the carbonization parameters.
[0054] In the present application, the carbonization is preferably carried out in an inert atmosphere, which is preferably argon or nitrogen.
[0055] In the present application, the acid used in the acidification preferably comprises one or more of phosphoric acid, sulfuric acid and boric acid, and more preferably is phosphoric acid. In the present application, the mass concentration of the acid is preferably 5-10 wt%, and more preferably 6-8 wt%. The present application can fully remove the impurities in the carbon material obtained after carbonization by using the above-mentioned acid for acidification, so that the activated carbon has abundant pore structure.
[0056] The present application does not have special limitation on the amount of the acid used in the acidification, and the carbon material obtained after carbonization can be completely immersed in the acid.
[0057] In the present application, the temperature of the acid immersion is preferably 50-80℃, and more preferably 60-70℃, and the time of the acid immersion is preferably 3-6h, and more preferably 5-6h. The present application can fully remove the impurities in the carbon material obtained after carbonization under the above-mentioned parameters of the acid immersion.
[0058] The present application does not have special limitation on the method of the water washing, and the acid in the carbon material after the acidification can be fully removed.
[0059] The present application preferably dries the carbon material obtained after the water washing to obtain activated carbon. In the present application, the temperature of the drying is preferably 80-120℃, and more preferably 100-110℃, and the time of the drying is preferably 1-3h, and more preferably 2-3h. The present application can fully remove the water remaining in the activated carbon by drying.
[0060] The present application mixes mercury chloride, stannous chloride, barium chloride, calcium chloride and yttrium chloride with water to obtain an impregnation solution.
[0061] In the present application, the amount of the mercury chloride, stannous chloride, barium chloride, calcium chloride and yttrium chloride is according to the amount used in the low-mercury catalyst with slow catalytic activity decay described in the above technical solution, which is not described here again.
[0062] The present application does not have special limitation on the amount of the water, and each component can be fully dissolved. In the present application, the mass concentration of the impregnation solution solute is preferably 1-5%, and more preferably 3-5%.
[0063] The present application does not have special limitation on the method of mixing the mercury chloride, stannous chloride, barium chloride, calcium chloride and yttrium chloride with water, and each component can be dissolved in water.
[0064] After obtaining the activated carbon and the impregnation solution, the present application immerses the activated carbon in the impregnation solution to obtain a low-mercury catalyst.
[0065] In the present application, the temperature of the impregnation is preferably 80-90℃, more preferably 85-90℃; the time of the impregnation is preferably 3-6h, more preferably 4-5h. By the impregnation at the above temperature and time, the present application can make the mercury chloride, stannous chloride, barium chloride, calcium chloride and yttrium chloride fully adsorbed into the pores of the activated carbon.
[0066] In the present application, the temperature of the drying is preferably 80-120℃, more preferably 100-110℃; the time of the drying is preferably 1-3h, more preferably 2-3h. By the drying, the present application can fully remove the residual water in the low-mercury catalyst.
[0067] The preparation method provided by the present application is simple in operation and can obtain activated carbon with high mechanical strength, high porosity and specific surface area, and good adsorption capacity for active components.
[0068] The technical solutions in the present application will be clearly and completely described below in combination with the embodiments in the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.
[0069] Embodiment 1
[0070] A low-mercury catalyst with slow catalytic activity decay, each component is as follows in percentage by mass: mercury chloride 1.5%, stannous chloride 1%, barium chloride 0.5%, calcium chloride 0.3%, yttrium chloride 0.3% and the balance of activated carbon; the strength of the activated carbon is 98%, the mesoporous rate of the activated carbon is 80%, and the specific surface area of the activated carbon is 3212m 2 / g;
[0071] The preparation method of the above low-mercury catalyst with slow catalytic activity decay is as follows:
[0072] (1) walnut shell is acid-impregnated in phosphoric acid with a concentration of 5wt% for 5h, then filtered, washed with water until the washed water is neutral, then dried at 110℃ for 2h, then ball-milled and sieved through a 200-mesh sieve to obtain a biomass powder;
[0073] (2) the biomass powder obtained in the step (1) is mixed with a binder (starch), an activating agent (85wt% phosphoric acid) and an appropriate amount of water to obtain a mixed slurry; wherein the mass of the binder accounts for 10% of the mass of the biomass powder, and the mass of the activating agent accounts for 8% of the mass of the biomass powder;
[0074] (3) extruding the mixed slurry obtained in step (2) into a cylindrical shape, drying for 2 h at 120℃ to form a shape, then increasing the temperature at a rate of 1℃ / min to 450℃, and carbonizing at this temperature for 5 h; then immersing the carbonized carbon material in a phosphoric acid solution with a concentration of 6wt% and a temperature of 60℃ for 5 h, then washing with water until the washing water is neutral, and then drying at 110℃ for 2 h to obtain activated carbon, which, when tested, has a strength of 98%, a mesopore rate of 80%, and a specific surface area of 3212m 2 / g;
[0075] (4) mixing mercury chloride, stannous chloride, barium chloride, calcium chloride, and yttrium chloride with water to obtain an impregnation solution, the mass concentration of the solute in the impregnation solution being 5%;
[0076] (5) immersing the activated carbon obtained in step (3) in the impregnation solution obtained in step (4) at 90℃ for 3 h, then taking it out and drying at 110℃ for 2 h to obtain a low-mercury catalyst.
[0077] Example 2
[0078] A low-mercury catalyst with slow catalytic activity decay, each component of which is, by mass percentage: mercury chloride 1.2%, stannous chloride 1.5%, barium chloride 0.3%, calcium chloride 0.3%, yttrium chloride 0.3%, and the balance activated carbon; the activated carbon has a strength of 98%, a mesopore rate of 80%, and a specific surface area of 3212m 2 / g;
[0079] The preparation method of the above low-mercury catalyst with slow catalytic activity decay is the same as that of Example 1.
[0080] Example 3
[0081] A low-mercury catalyst with slow catalytic activity decay, each component of which is, by mass percentage: mercury chloride 2%, stannous chloride 0.5%, barium chloride 0.5%, calcium chloride 0.3%, yttrium chloride 0.3%, and the balance activated carbon; the activated carbon has a strength of 98%, a mesopore rate of 80%, and a specific surface area of 3212m 2 / g;
[0082] The preparation method of the above low-mercury catalyst with slow catalytic activity decay is the same as that of Example 1.
[0083] Example 4
[0084] A low-mercury catalyst with slow catalytic activity degradation, each component is 1% of mercuric chloride, 2% of stannous chloride, 0.5% of barium chloride, 0.5% of calcium chloride, 0.5% of yttrium chloride and the balance of activated carbon in percentage by mass; the strength of the activated carbon is 98%, the mesoporous rate of the activated carbon is 80%, and the specific surface area of the activated carbon is 3212m 2 / g;
[0085] The preparation method of the above-mentioned low-mercury catalyst with slow catalytic activity degradation is the same as that of example 1.
[0086] Example 5
[0087] A low-mercury catalyst with slow catalytic activity degradation, each component is 1.5% of mercuric chloride, 1% of stannous chloride, 0.5% of barium chloride, 0.3% of calcium chloride, 0.3% of yttrium chloride and the balance of activated carbon in percentage by mass; the strength of the activated carbon is 96%, the mesoporous rate of the activated carbon is 88%, and the specific surface area of the activated carbon is 3789m 2 / g;
[0088] The preparation method of the above-mentioned low-mercury catalyst with slow catalytic activity degradation is:
[0089] (1) Walnut shell is immersed in phosphoric acid with a concentration of 8wt% for 5h, then filtered, washed with water until the washing water is neutral, then dried at 110℃ for 2h, then ball milled and sieved through a 200 mesh sieve to obtain biomass powder;
[0090] (2) The biomass powder obtained in step (1) is mixed with a binder (sodium carboxymethyl cellulose), an activator (85wt.% phosphoric acid) and an appropriate amount of water to obtain a mixed slurry; wherein the mass of the binder accounts for 15% of the mass of the biomass powder, and the mass of the activator accounts for 10% of the mass of the biomass powder;
[0091] (3) The mixed slurry obtained in step (2) is extruded into a cylindrical blank, dried at 120℃ for 2h for molding, then heated to 600℃ at a heating rate of 2℃ / min, and kept at this temperature for 4h for carbonization; then the carbonized carbon material is soaked in a phosphoric acid solution with a concentration of 6wt% and a temperature of 60℃ for 5h, then washed with water until the washing water is neutral, then dried at 110℃ for 2h to obtain activated carbon, which is tested to have a strength of 96%, a mesoporous rate of 88%, and a specific surface area of 3789m 2 / g;
[0092] (4) Mercuric chloride, stannous chloride, barium chloride, calcium chloride and yttrium chloride are mixed with water to obtain an impregnation solution, and the mass concentration of solutes in the impregnation solution is 5%;
[0093] (5) The activated carbon obtained in step (3) is immersed in the impregnation solution obtained in step (4) at 90°C for 3h, and then taken out and dried at 110°C for 2h to obtain a low-mercury catalyst.
[0094] Comparative Example 1
[0095] A low-mercury catalyst, each component is, by mass percentage: mercury chloride 2%, barium chloride 0.5%, calcium chloride 0.3%, yttrium chloride 0.3%, and the balance is activated carbon; the strength of the activated carbon is 96%, the mesoporous rate of the activated carbon is 80%, and the specific surface area of the activated carbon is 3212m 2 / g.
[0096] The preparation method of the above-mentioned low-mercury catalyst with slow catalytic activity decay is the same as that of Example 1.
[0097] Comparative Example 2
[0098] A low-mercury catalyst with slow catalytic activity decay, each component is, by mass percentage: mercury chloride 2%, stannous chloride 0.5%, calcium chloride 0.3%, yttrium chloride 0.3%, and the balance is activated carbon; the strength of the activated carbon is 98%, the mesoporous rate of the activated carbon is 80%, and the specific surface area of the activated carbon is 3212m 2 / g.
[0099] The preparation method of the above-mentioned low-mercury catalyst with slow catalytic activity decay is the same as that of Example 1.
[0100] Comparative Example 3
[0101] A low-mercury catalyst with slow catalytic activity decay, each component is, by mass percentage: mercury chloride 1.5%, stannous chloride 1%, barium chloride 0.5%, calcium chloride 0.3%, yttrium chloride 0.3%, and the balance is activated carbon; the activated carbon is a commercially available activated carbon, the mesoporous rate of the activated carbon is 28%, and the specific surface area of the activated carbon is 750m 2 / g.
[0102] The preparation method of the above-mentioned low-mercury catalyst with slow catalytic activity decay is:
[0103] (1) Mix mercury chloride, stannous chloride, barium chloride, calcium chloride, and yttrium chloride with water to obtain an impregnation solution, and the mass concentration of the solute in the impregnation solution is 5%;
[0104] (2) The commercially available activated carbon is immersed in the impregnation solution obtained in step (2) at 90°C for 3h, and then taken out and dried at 110°C for 2h to obtain a low-mercury catalyst.
[0105] Test Example
[0106] The performance test results of the low-mercury catalysts prepared in Examples 1-5 and Comparative Examples 1-3 after 8000 hours of use as a catalyst for synthesizing chloroethylene are shown in Table 1:
[0107] Table 1 Performance test results of low-mercury catalysts prepared by different methods after use
[0108]
[0109]
[0110] As can be seen from Table 1, the method provided by the present application has excellent activity retention rate, low mercury loss rate, and good stability. This is because the present application uses stannous chloride, barium chloride, calcium chloride, and yttrium chloride to replace part of the mercuric chloride, which can reduce the amount of mercuric chloride in the catalyst while ensuring the catalytic performance, thereby reducing the production cost of the catalyst and reducing the loss of mercury; the active carbon with large specific surface area, high mechanical properties, and high porosity used as the carrier in the present application is more conducive to the fixation of mercury and other chlorides in the pores, thereby reducing the loss of mercury; and, the catalyst can also reduce the dispersion and relaxation of the catalyst during use, thereby improving the service life of the low-mercury catalyst.
[0111] The above description is only preferred embodiments of the present application, and it should be pointed out that those skilled in the art can make several improvements and refinements without departing from the principles of the present application, and these improvements and refinements should also be considered within the protection scope of the present application.
Claims
1. A low-mercury catalyst with slow deactivation of catalytic activity, comprising, by mass percentage: Mercury chloride 1-2%, stannous chloride 0.2-2%, barium chloride 0.1-0.5%, calcium chloride 0.1-0.5%, yttrium chloride 0.2-0.3% and the rest of activated carbon; the strength of the activated carbon is ≥ 96%, the mesoporous rate of the activated carbon is 70-90%, the specific surface area of the activated carbon is ≥ 3200 m 2 / g.
2. The method for preparing a low-mercury catalyst with slow catalytic activity decay according to claim 1, comprising the following steps: (1) sequentially subjecting a shell to acid immersion and crushing to obtain a biomass powder; (2) mixing the biomass powder obtained in step (1) with a binder, an activator and water to obtain a mixed slurry; (3) sequentially subjecting the mixed slurry obtained in step (2) to shaping, carbonization, acidification and water washing to obtain activated carbon; (4) mixing mercury chloride, stannous chloride, barium chloride, calcium chloride and yttrium chloride with water to obtain an impregnation solution; (5) subjecting the activated carbon obtained in step (3) to impregnation in the impregnation solution obtained in step (4) to obtain a low-mercury catalyst.
3. The preparation method according to claim 2, characterized in that, The shell in step (1) comprises one or more of peanut shell, coconut shell and walnut shell.
4. The preparation method according to claim 2, characterized in that, The acid solution used in the acid immersion in step (1) comprises one or more of phosphoric acid, sulfuric acid and boric acid.
5. The preparation method according to claim 2, characterized in that, The binder in step (2) comprises one or more of starch, polyvinyl alcohol and sodium carboxymethyl cellulose.
6. The production method according to claim 2 or 5, characterized by, The mass of the binder accounts for 1-15% of the mass of the biomass powder.
7. The preparation method according to claim 2, characterized in that, The activator in step (2) comprises phosphoric acid or zinc oxide.
8. The production method according to claim 2 or 7, characterized by, The mass of the activator accounts for 1-10% of the mass of the biomass powder.
9. The preparation method according to claim 2, characterized in that, The carbonization temperature in step (3) is 350-800°C, and the carbonization time is 2-6h.
10. The method of claim 2, wherein, The impregnation temperature in step (5) is 80-90°C, and the impregnation time is 3-6h.