Preparation method of stainless steel carrier loaded palladium-based multi-metal catalyst and application thereof

Abstract

The present application belongs to the technical field of catalyst preparation, and particularly relates to a preparation method and application of a stainless steel carrier loaded Pd-based multi-metal catalyst. The technical scheme disclosed by the present application improves the interaction between the carrier and the active metal by sulfidizing the surface of the stainless steel carrier, simultaneously anchors and disperses the active metal, improves the electronic structure of the active metal, and synchronously improves the performance of the carrier in the selective hydrogenation reaction of acetylene from the aspects of rapid heat conduction and electronic properties. The loaded Pd multi-metal catalyst is prepared by an impregnation method; Pd is the active center of the reaction, and the second metal M2 and the third metal M3 can separate Pd atoms and improve the electronic properties of the Pd surface. The present application can solve the problem that the existing metal oxide carrier has slow heat conduction and is prone to form local hot spots in the process of the selective hydrogenation reaction of acetylene.

Description

Technical Field

[0001] This invention belongs to the field of catalyst preparation technology, specifically relating to a method for preparing a Pd-based multimetallic catalyst supported on a stainless steel support and its application. Background Technology

[0002] The selective hydrogenation of acetylene plays an irreplaceable and crucial role in the ethylene industry. This process aims to remove ppm-level acetylene impurities from the ethylene feedstock gas, thereby preventing acetylene from poisoning the catalyst during downstream polymerization and ensuring the purity and quality of the polyethylene product. However, this reaction is accompanied by a strong exothermic effect (main reaction ΔH≈-170kJ / mol), and the side reaction of deep hydrogenation of acetylene to ethane releases even more heat (ΔH≈-300kJ / mol). In industrial fixed-bed reactors, if heat is not removed in time, localized "hot spots" can easily form, leading to runaway temperatures. Runaway temperatures not only significantly reduce ethylene selectivity, causing a large amount of feedstock ethylene to be over-hydrogenated into low-value ethane, but more seriously, the drastic temperature rise can cause the active components of the catalyst to aggregate and sinter, destroy the support structure, and even lead to uncontrolled pressure inside the reactor, inducing major safety accidents such as boiling over, coking and blockage, or even explosions and leaks.

[0003] Therefore, developing high thermal conductivity acetylene selective hydrogenation catalysts to prevent the formation of localized "hot spots" is crucial for ensuring the safe and economical operation of this process. While metallic materials generally possess high thermal conductivity, their interaction with the commonly used active metal Pd is weak. Therefore, effective preparation methods for metal-supported acetylene selective hydrogenation catalysts still need to be developed. Summary of the Invention

[0004] Therefore, the purpose of this invention is to provide a method for preparing a Pd-based multimetallic catalyst supported on a stainless steel support and its application in the selective hydrogenation reaction of acetylene. By sulfiding the surface of the stainless steel support, the interaction between the support and the active metal is enhanced. This not only anchors and disperses the active metal but also improves the electronic structure of the active metal, thereby simultaneously improving its performance in the selective hydrogenation reaction of acetylene from both the aspects of rapid thermal conductivity and electronic properties.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] In a first aspect, the present invention provides a method for preparing a Pd-based multimetallic catalyst supported on a stainless steel support, comprising the following steps: S1: Prepare a sulfide solution in deionized water, then add a stainless steel carrier, place it in an oven for immersion to perform surface sulfidation, wash with deionized water and dry to obtain the sulfidated carrier. S2: Pd salt solution, second metal salt solution and third metal salt solution are added to deionized water to form a mixed solution. The sulfided support is then added for impregnation and dried to obtain the catalyst precursor. S3: The catalyst precursor is placed in a hydrogen atmosphere and reduced to obtain a stainless steel supported Pd-based multimetal catalyst (PdM2M3).

[0007] Based on the above technical solution, in step S1, the sulfide is selected from one of sodium sulfide, potassium sulfide, ammonium sulfide, sodium hydrosulfide, sodium polysulfide, and ammonium polysulfide, and the concentration of the sulfide solution is 0.15-10 mg / ml; The volume ratio of the sulfide solution to the stainless steel carrier in step S1 is 1:1 to 5:1; The types of stainless steel carriers include, but are not limited to, austenitic stainless steel, ferritic stainless steel, and martensitic stainless steel. The shape of the stainless steel carrier includes, but is not limited to, stainless steel shot, stainless steel θ ring, and stainless steel wire ball, preferably steel shot-201, steel shot-304, steel shot-410, steel shot-430, stainless steel θ ring, and 316 stainless steel wire ball.

[0008] Based on the above technical solution, the surface vulcanization in step S1 is specifically: immersing in an oven at 40-120℃ for 1-15 hours; The drying process in step S1 specifically involves drying at 40-120℃ for 3-48 hours.

[0009] Based on the above technical solution, in step S2, the volume ratio of deionized water, Pd salt solution, second metal salt solution, and third metal salt solution is 4-50:0.01-5:0.01-5:0.01-5, wherein the concentration of Pd salt solution is 1-50 mg / mL, the concentration of second metal salt solution is 1-50 mg / mL, and the concentration of third metal salt solution is 1-50 mg / mL. In step S2, drying II specifically involves drying at 40-120℃ for 3-12 hours. The mass ratio of the mixed solution to the sulfidated carrier in step S2 is 1:1 to 1:5; The impregnation described in step S2 specifically involves impregnating at 40-120℃ for 3-48 hours.

[0010] Based on the above technical solution, the Pd salt in the Pd salt solution includes, but is not limited to, palladium chloride, palladium nitrate, palladium acetate, and palladium acetylacetone; The second metal salt solution includes, but is not limited to, sulfates, nicotinates, nitrates, and acetates of Cu, Ag, In, Ga, and Zn, and is preferably zinc nitrate, silver nitrate, gallium nitrate, copper nitrate, and indium nitrate; The third metal salt solution includes, but is not limited to, sulfates, nicotinates, nitrates and acetates of Bi, Mn and Sb, and is preferably manganese nitrate, bismuth nitrate and antimony nitrate.

[0011] Based on the above technical solution, the reduction in step S3 is specifically as follows: in a hydrogen atmosphere with a concentration of 5-100%, the reduction is carried out at 50-500℃ for 1-5 hours.

[0012] Based on the above technical solution, the Pd-based multimetal catalyst supported on the stainless steel carrier has a Pd content of 0.001-2wt%, a second metal content of 0.001-5wt%, and a third metal content of 0.001-3wt%. The Pd, the second metal, the third metal, and S form metal sulfides anchored on the stainless steel surface.

[0013] Secondly, an application of a stainless steel-supported Pd-based multimetallic catalyst in the selective hydrogenation reaction of acetylene is provided, comprising the following steps: in-situ reduction of the stainless steel-supported Pd-based multimetallic catalyst, cooling to 30-80℃, introducing raw material gas, reacting, and obtaining a product containing ethylene.

[0014] Based on the above technical solution, the composition of the raw gas is: 0.1% CH4, 18.9% C2H6, 80% C2H4, 0.4% C2H2, and 0.6% H2, based on a volume percentage of 100%. The space velocity of the raw gas is 3000-8000 h⁻¹. -1 .

[0015] Based on the above technical solution, the reaction temperature is 30-200℃, preferably 50-100℃.

[0016] Beneficial effects The technical solution disclosed in this invention uses stainless steel as the catalyst support for the selective hydrogenation of acetylene, which can rapidly conduct and disperse the heat generated by the reaction, preventing the formation of local hot spots. Sulfide treatment of the stainless steel support surface helps anchor and disperse the metal on its surface and improves the electronic structure of the active metal. In the resulting PdM2M3 / stainless steel catalyst, Pd is the active center of the reaction, and the second metal M2 and the third metal M3 can separate Pd atoms and improve the electronic properties of the Pd surface. This invention innovatively develops a method for preparing Pd-based catalysts with stainless steel as the support, which can solve the problem of slow thermal conductivity and easy formation of local hot spots in the selective hydrogenation of acetylene using existing metal oxide supports. Attached Figure Description

[0017] To more clearly illustrate the embodiments of the present invention, the accompanying drawings involved in the embodiments will be briefly described below.

[0018] Figure 1An optical image of the PdZnMnS / steel shot-304 catalyst of Example 1 of the present invention; Figure 2 The graph shows the selective hydrogenation performance of acetylene using the PdZnMnS / steel shot-304 catalyst in Example 1 of this invention. Figure 3 This is a graph showing the selective hydrogenation performance of acetylene using the PdAgBiS / steel shot-304 catalyst in Example 2 of this invention. Figure 4 This is a graph showing the selective hydrogenation performance of acetylene using the PdGaBiS / steel shot-304 catalyst in Example 3 of this invention. Figure 5 An optical image of the PdZnMnS / θ ring catalyst of Example 4 of this invention; Figure 6 This is a graph showing the selective hydrogenation performance of the PdZnMnS / θ ring catalyst in Example 4 of this invention. Figure 7 This is a graph showing the selective hydrogenation performance of the PdCuSbS / θ ring catalyst in Example 5 of the present invention for acetylene. Figure 8 The graph shows the selective hydrogenation performance of the PdGaBiS / θ-ring catalyst in Example 6 of this invention for acetylene. Figure 9 Optical images of PdZnMnS / steel wool balls from Embodiment 7 of the present invention; Figure 10 The graph shows the selective hydrogenation performance of PdZnMnS / steel wool in Example 7 of this invention. Figure 11 The graph shows the selective hydrogenation performance of PdInSbS / steel wool in Example 8 of this invention. Figure 12 The graph shows a performance comparison of the PdCuBiS / θ ring and the PdCuBi / θ ring of Comparative Example 1 of the present invention in the selective hydrogenation reaction of acetylene (A: conversion, B: selectivity). Figure 13 This is a comparison chart of the performance of catalysts prepared using steel shot of different materials as supports in the selective hydrogenation reaction of acetylene in Example 9 of the present invention (A: conversion rate, B: selectivity). Detailed Implementation

[0019] To make the objectives and technical solutions of this invention clearer, the following embodiments are provided for further explanation. However, the scope of protection of this invention is not limited to these embodiments; the embodiments are merely for illustrative purposes. Those skilled in the art should understand that any changes or equivalent substitutions that do not depart from the concept of this invention are included within the scope of protection of this invention.

[0020] Unless otherwise specified, all reagents and raw materials used in this invention are obtained through purchase.

[0021] Example 1 A solution was prepared by adding 5 mg of ammonium sulfide to 5 ml of deionized water. Then, 10 mL of 304 stainless steel shot (hardness HRC 25-30, size 1.5-2.5 mm, purchased from Jiangsu Xinghai Metal Products Co., Ltd., Cr content 18%, Ni content 8%) was added. The solution was then immersed in a 60℃ oven for 8 hours for surface sulfidation. After washing with deionized water and drying at 60℃ for 12 hours, product A (the sulfidated carrier) was obtained. In another solution, 0.2 mL of a palladium nitrate aqueous solution with a Pd content of 10 mg / mL and 0.5 mL of a Zn(NO3)2·6H2O aqueous solution with a Zn content of 20 mg / mL were added to 5 ml of deionized water. Mn content... 0.5 mL of a 20 mg / mL Mn(NO3)2·4H2O aqueous solution was mixed thoroughly, and 40 g of product A was added and impregnated at 60 °C for 1 h. The solid was then transferred to an oven at 80 °C and dried for 24 h to obtain product B (catalyst precursor). Product B was then reduced at 300 °C for 2 h in a 20% hydrogen atmosphere (specifically, a 20% hydrogen volume fraction gas atmosphere with nitrogen balance; this is a standard atmosphere for catalyst reduction in the acetylene hydrogenation field) to obtain PdZnMnS / steel shot-304 (see...). Figure 1 The Pd content is 0.5 wt%, the Zn content is 1.0 wt%, and the Mn content is 0.5 wt%.

[0022] The selective hydrogenation performance of acetylene was evaluated using PdZnMnS / steel shot-304 as a catalyst. The reaction and testing conditions were as follows: a fixed-bed reactor was used for performance evaluation; 40g of catalyst was reduced in situ at 200℃ for 2h before the reaction, and then kept at a constant temperature of 80℃ while introducing feed gas; the feed gas composition (volume ratio) was 0.1% CH4, 18.9% C2H6, 80% C2H4, 0.4% C2H2, and 0.6% H2, with a feed gas space velocity of 6000 h⁻¹. -1 The gaseous products of the reaction were analyzed online using a gas chromatograph (Agilent, 7890B) equipped with an HP-PLOT AL2O3M capillary column to determine the conversion of acetylene and the selectivity for ethylene. The evaluation results are shown in [link to evaluation]. Figure 2 .

[0023] Example 2 The difference from Example 1 is that 0.5 mL of a Zn(NO3)2·6H2O aqueous solution with a Zn content of 20 mg / mL and 0.5 mL of a Mn(NO3)2·4H2O aqueous solution with a Mn content of 20 mg / mL were replaced with 0.5 mL of an AgNO3 aqueous solution with a Ag content of 20 mg / mL and 0.5 mL of a Bi(NO3)3·5H2O aqueous solution with a Bi content of 20 mg / mL. The resulting catalyst is designated as PdAgBiS / Steel Shot-304. Using PdAgBiS / Steel Shot-304 as the catalyst (Pd content 0.5 wt%, Ag content 1.0 wt%, Bi content 0.5 wt%), the selective hydrogenation performance of acetylene was evaluated. The evaluation results are shown in […]. Figure 3 .

[0024] Example 3 The difference from Example 1 is that 0.5 mL of a Zn(NO3)2·6H2O aqueous solution with a Zn content of 20 mg / mL and 0.5 mL of a Mn(NO3)2·4H2O aqueous solution with a Mn content of 20 mg / mL were replaced with 0.5 mL of a Ga(NO3)3·xH2O aqueous solution with a Ga content of 20 mg / mL and 0.5 mL of a Bi(NO3)3·5H2O aqueous solution with a Bi content of 20 mg / mL. The resulting catalyst is designated as PdGaBiS / Steel Shot-304 (Pd content 0.5 wt%, Ga content 1.0 wt%, Bi content 0.5 wt%). The selective hydrogenation performance of acetylene was evaluated using PdGaBiS / Steel Shot-304 as a catalyst. The evaluation results are shown in […]. Figure 4 .

[0025] Depend on Figure 2 , Figure 3 and Figure 4 The comparison shows that PdZnMnS / steel shot-304 has the highest activity and selectivity, followed by PdGaBiS / steel shot-304, and PdAgBiS / steel shot-304 has the worst activity and selectivity.

[0026] Example 4 The difference from Example 1 is that the 304 stainless steel shot is replaced with stainless steel θ rings (φ is 3×3mm, mesh size is 100-200 mesh, material is 304 stainless steel, porosity is 92%-95%, specific surface area is 800-1200m²). 2 / m 3 The catalyst (purchased from Jiangxi Kailai Chemical Packing Co., Ltd.) was prepared by adding 10 mL of stainless steel θ rings, resulting in a bulk density of 0.45-0.55 g / mL. The catalyst is denoted as PdZnMnS / θ rings (see [link to catalyst description]). Figure 5 The selective hydrogenation performance of acetylene was evaluated using PdZnMnS / θ ring catalysts. The evaluation results are shown in [Figure number missing]. Figure 6 .

[0027] Example 5 The difference from Example 4 is that 0.5 mL of a Zn(NO3)2·6H2O aqueous solution with a Zn content of 20 mg / mL and 0.5 mL of a Mn(NO3)2·4H2O aqueous solution with a Mn content of 20 mg / mL were replaced with 0.5 mL of a Cu(NO3)2·3H2O aqueous solution with a Cu content of 20 mg / mL and 0.5 mL of a Sb(NO3)3 aqueous solution with a Sb content of 20 mg / mL. The resulting catalyst is denoted as PdCuSbS / θ ring (Pd content 0.5 wt%, Cu content 1.0 wt%, Sb content 1.0 wt%). The performance of the PdCuSbS / θ ring catalyst in the selective hydrogenation reaction of acetylene was evaluated, and the evaluation results are shown in […]. Figure 7 .

[0028] Example 6 The difference from Example 1 is that 0.5 mL of a Zn(NO3)2·6H2O aqueous solution with a Zn content of 20 mg / mL and 0.5 mL of a Mn(NO3)2·4H2O aqueous solution with a Mn content of 20 mg / mL were replaced with 0.5 mL of a Ga(NO3)3·xH2O aqueous solution with a Ga content of 20 mg / mL and 0.5 mL of a Bi(NO3)3·5H2O aqueous solution with a Bi content of 20 mg / mL. The resulting catalyst is denoted as PdGaBiS / θ ring (Pd content 0.5 wt%, Ga content 1.0 wt%, Bi content 1.0 wt%). The performance of the PdGaBiS / θ ring catalyst in the selective hydrogenation reaction of acetylene was evaluated, and the evaluation results are shown in […]. Figure 8 .

[0029] Depend on Figure 6 , Figure 7 and Figure 8 The comparison shows that the PdZnMnS / θ ring has poor activity, while the PdCuSbS / θ ring and PdGaBiS / θ ring have comparable activity and selectivity.

[0030] Example 7 The difference from Example 1 is that the 304 stainless steel shot is replaced with stainless steel wire balls (wire diameter 0.1-0.2mm, packed porosity 92-96%, specific surface area 850-1200m²). 2 / m 3 (Purchased from Miaojie Company), that is, add 10mL of 316 stainless steel wire balls, the bulk concentration is 3.5-4.5g / ml, and the resulting catalyst is denoted as PdZnMnS / steel wire balls (see Figure 9 The selective hydrogenation performance of acetylene was evaluated using PdZnMnS / steel wool as a catalyst. The evaluation results are shown in […]. Figure 10 .

[0031] Example 8 The difference from Example 7 is that 0.5 mL of a Zn(NO3)2·6H2O aqueous solution with a Zn content of 20 mg / mL and 0.5 mL of a Mn(NO3)2·4H2O aqueous solution with a Mn content of 20 mg / mL were replaced with 0.5 mL of an In(NO3)3·xH2O aqueous solution with an In content of 20 mg / mL and 0.5 mL of an Sb(NO3)3 aqueous solution with a Sb content of 20 mg / mL. The resulting catalyst is denoted as PdInSbS / steel wool (Pd content 0.5 wt%, In content 1.0 wt%, Sb content 1.0 wt%). The performance of PdInSbS / steel wool as a catalyst for selective hydrogenation of acetylene was evaluated, and the evaluation results are shown in […]. Figure 11 .

[0032] Depend on Figure 10 and Figure 11 The comparison shows that PdZnMn / steel wool has poor low-temperature activity, while PdInSbS / steel wool exhibits better activity and selectivity in the low-temperature range (45~55℃).

[0033] Comparative Example 1 The difference from Example 5 is that 0.5 ml of an aqueous solution of Sb(NO3)3 with a Sb content of 20 mg / mL was replaced with 0.5 ml of an aqueous solution of Bi(NO3)3·5H2O with a Bi content of 20 mg / mL to prepare the PdCuBiS / θ ring catalyst; simultaneously, no sulfide sulfidation treatment was performed, and the PdCuBi / θ catalyst was prepared directly by impregnation. The test conditions were the same as in Example 1, and the test results are as follows. Figure 12 As shown, surface sulfidation treatment can effectively improve the activity and selectivity of Pd-based catalysts in the acetylene hydrogenation reaction.

[0034] Example 9 The difference from Example 1 is that 0.5 ml of a Mn(NO3)2·4H2O aqueous solution with a Sb content of 20 mg / mL was replaced with 0.5 ml of a Sb(NO3)3 aqueous solution with a Sb content of 20 mg / mL. PdZnSbS / Steel Shot-201, PdZnSbS / Steel Shot-304, PdZnSbS / Steel Shot-410, and PdZnSbS / Steel Shot-430 were prepared using steel shot-201, steel shot-304, steel shot-410, and steel shot-430 as carriers, respectively. The test conditions were the same as in Example 1, and the test results are as follows. Figure 13As shown, stainless steel shot of different materials exhibits similar performance in the selective hydrogenation reaction of acetylene after surface sulfidation treatment, indicating that the preparation of Pd-based metal-supported catalysts by surface sulfidation treatment has a certain degree of universality.

[0035] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A method for preparing a Pd-based multimetallic catalyst supported on a stainless steel support, characterized in that, Includes the following steps: S1: Prepare a sulfide solution in deionized water, then add a stainless steel carrier, place it in an oven for immersion to perform surface sulfidation, wash with deionized water and dry to obtain the sulfidated carrier. S2: Pd salt solution, second metal salt solution and third metal salt solution are added to deionized water to form a mixed solution. The sulfided support is then added for impregnation and dried to obtain the catalyst precursor. S3: The catalyst precursor is placed in a hydrogen atmosphere and reduced to obtain a stainless steel supported Pd-based multimetal catalyst.

2. The preparation method according to claim 1, characterized in that, In step S1, the sulfide is selected from one of sodium sulfide, potassium sulfide, ammonium sulfide, sodium hydrosulfide, sodium polysulfide, and ammonium polysulfide, and the concentration of the sulfide solution is 0.15-10 mg / ml; The volume ratio of the sulfide solution to the stainless steel carrier in step S1 is 1:1 to 5:

1.

3. The preparation method according to claim 1, characterized in that, The types of stainless steel carriers include, but are not limited to, austenitic stainless steel, ferritic stainless steel, and martensitic stainless steel. The shape of the stainless steel carrier includes, but is not limited to, stainless steel shot, stainless steel θ ring, and stainless steel wire ball, preferably steel shot-201, steel shot-304, steel shot-410, steel shot-430, stainless steel θ ring, and 316 stainless steel wire ball.

4. The preparation method according to claim 1, characterized in that, The surface vulcanization in step S1 specifically involves immersing the product in an oven at 40-120℃ for 1-15 hours. The drying process in step S1 specifically involves drying at 40-120℃ for 3-48 hours.

5. The preparation method according to claim 1, characterized in that, In step S2, the volume ratio of deionized water, Pd salt solution, second metal salt solution, and third metal salt solution is 4-50:0.01-5:0.01-5:0.01-5, wherein the concentration of Pd salt solution is 1-50 mg / mL, the concentration of second metal salt solution is 1-50 mg / mL, and the concentration of third metal salt solution is 1-50 mg / mL. In step S2, drying II specifically involves drying at 40-120℃ for 3-12 hours. The mass ratio of the mixed solution to the sulfidated carrier in step S2 is 1:1 to 1:5; The impregnation described in step S2 specifically involves impregnating at 40-120℃ for 3-48 hours.

6. The preparation method according to claim 1, characterized in that, The Pd salt in the Pd salt solution includes, but is not limited to, palladium chloride, palladium nitrate, palladium acetate, and palladium acetylacetone; The second metal salt solution includes, but is not limited to, sulfates, nicotinates, nitrates, and acetates of Cu, Ag, In, Ga, and Zn, and is preferably zinc nitrate, silver nitrate, gallium nitrate, copper nitrate, and indium nitrate; The third metal salt solution includes, but is not limited to, sulfates, nicotinates, nitrates and acetates of Bi, Mn and Sb, and is preferably manganese nitrate, bismuth nitrate and antimony nitrate.

7. The preparation method according to claim 1, characterized in that, The reduction in step S3 specifically involves reducing the hydrogen at 50-500°C for 1-5 hours in a hydrogen atmosphere with a concentration of 5-100%. The stainless steel-supported Pd-based multimetallic catalyst contains 0.001-2 wt% Pd, 0.001-5 wt% second metal, and 0.001-3 wt% third metal.

8. The application of a stainless steel-supported Pd-based multimetallic catalyst in the selective hydrogenation of acetylene, characterized in that, The process includes the following steps: in-situ reduction of Pd-based multimetallic catalyst supported on a stainless steel support, cooling to 30-80℃, introducing raw material gas, reacting, and obtaining a product containing ethylene.

9. The application according to claim 8, characterized in that, The composition of the raw gas is: 0.1% CH4, 18.9% C2H6, 80% C2H4, 0.4% C2H2, and 0.6% H2, based on a 100% volume percentage; The space velocity of the raw gas is 3000-8000 h⁻¹. -1 .

10. The application according to claim 8, characterized in that, The reaction temperature is 30-200℃, preferably 50-100℃.

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