WO2024240099A1 - High-dispersity ruthenium catalyst for oxidizing hydrogen chloride to prepare chlorine and preparation method therefor - Google Patents

Abstract

The present application relates to the field of catalysts, and in particular to a high-dispersity ruthenium catalyst for oxidizing hydrogen chloride to prepare chlorine and a preparation method therefor. The method comprises: impregnating, with an impregnation liquid pre-mixed with a surfactant, a composite carrier prepared by means of using titanium oxide and aluminum oxide or a porous carrier prepared by means of using titanium oxide, high-thermal-conductivity ceramic and an auxiliary agent, and subjecting same to processes such as drying, calcining, cooling, water washing and drying, so as to obtain the ruthenium catalyst. The catalyst of the present application improves the metal dispersity, reduces the use amount of active metal, and has high thermal stability, thereby prolonging the service life of the catalyst.

Description

A high-dispersion ruthenium catalyst for preparing chlorine by oxidation of hydrogen chloride and a preparation method thereof Technical Field

The present application relates to the field of catalysts, and in particular to a high-dispersion ruthenium catalyst for preparing chlorine by hydrogen chloride oxidation and a preparation method thereof.

Background Art

Chlorine is an important basic chemical raw material, widely used in chemical, metallurgical, papermaking, textile, petrochemical, drinking water disinfection and environmental protection industries. When producing organochlorine products in industry, a large amount of by-product hydrogen chloride is produced, with the maximum atomic utilization rate of 50%. Most of these hydrogen chloride gases are absorbed by water to make hydrochloric acid, but they contain organic impurities, which limits their use. As people's environmental awareness increases, the requirements for the transportation management and discharge of toxic and highly corrosive substances such as chlorine and hydrogen chloride are becoming more and more stringent, and the by-product hydrogen chloride is becoming more and more difficult to handle. Converting hydrogen chloride to prepare chlorine can realize the closed-loop recycling of chlorine resources. It is the most effective method for processing and recovering by-product hydrogen chloride, and a high degree of consensus has been formed in the chlorine-related industry.

Catalytic oxidation is the most effective solution, especially the catalytic oxidation via the Deacon reaction, which has the greatest potential for industrialization due to its simple operation and low equipment cost. In the method for catalytic oxidation of hydrogen chloride developed by Deacon in 1868, hydrogen chloride is oxidized to chlorine by oxygen exothermic equilibrium. The conversion of hydrogen chloride to chlorine allows the production of chlorine to be separated from the production of sodium hydroxide by chlor-alkali electrolysis. The separation is very attractive because the world demand for chlorine is higher than that for sodium hydroxide.

The most important factor of Deacon reaction is catalyst. After copper-based catalyst (Deacon catalyst), transition metal catalysts such as iron and chromium have been introduced one after another. In recent years, highly active ruthenium-based (Ru), cerium-based (Ce) and composite oxide catalysts have been developed. Copper-based catalysts have attracted much attention due to their low cost. In the Chinese patent application of Tsinghua University, publication number: CN101125297A, the name "an oxychlorination catalyst and its application" uses copper and oxide inert carriers, but as the reaction time at high temperature passes, copper particles will gather, and bridges will be formed between particles, causing the catalyst specific surface area to drop significantly, so that the activity decreases, thereby causing deactivation. Copper-containing hydrogen chloride oxidation catalysts can be loaded with carriers that are inert to the hydrogen chloride oxidation reaction system, such as U.S. patent application US4123389A using silica gel, aluminum oxide or titanium oxide as carriers, copper is the main active component, but the preparation process requires organic solvent impregnation, which is environmentally polluting.

Although chromium catalysts have good activity, chromium is highly toxic and its large-scale use has adverse effects on the environment. U.S. Patent No. 5716592A reports the use of a composite catalyst of chromium oxide and rare earth cerium, with a loading of 45 g of catalyst, an HCl flow rate of 0.3 L/min, and an O ₂ flow rate of 0.225 L/min, to catalytically oxidize hydrogen chloride at 380°C, with a conversion rate of up to 85.2%. Chromium is toxic and easily forms low-boiling chromium oxychloride with chlorine, which easily deactivates the catalyst.

Sumitomo Chemical Co., Ltd.'s Chinese patent application on ruthenium catalyst for hydrogen chloride oxidation catalysis technology CN1182717A, CN1150127C and CN1272238C disclose the preparation of ruthenium-based catalysts by impregnating ruthenium oxide and calcining oxides such as _TiO2 and _ZrO2 as carriers. In addition, WO2007/134772A1 of Bayer Materialscience AG discloses a ruthenium-based catalyst system containing tin dioxide.

Although compared with other catalysts, ruthenium-based catalysts have the characteristics of low dosage and high low-temperature activity, for example, the ruthenium-based catalyst prepared by loading _RuO2 and _SiO2 on _TiO2 in CN1182717A has better low-temperature catalytic performance. However, due to the existence of the exothermic effect of the reaction, the active component _RuO2 particles are prone to sintering due to insufficient heat dissipation. After long-term use, the catalyst still has the problem of decreased reaction activity.

CN1272238C of Sumitomo Chemical discloses that a _RuO2 catalyst supported on a composite carrier of rutile _TiO2 and α-alumina reduces the reaction temperature of the Deacon process to about 300°C, and increases the theoretical equilibrium conversion rate to 90%-95%. However, in actual use, it is found that when the temperature is higher than 360°C, especially when the temperature reaches above 390°C, the conversion rate drops sharply to below 80%. Ruthenium-based catalysts have two main advantages over other non-precious metal catalysts: first, they have good low-temperature activity at 300-350°C and high HCl equilibrium conversion rate; second, the chlorination of their surface active phase is self-limiting, and the catalyst will not generate volatile chlorides due to excessive chlorination. However, due to the high price of precious metals, the economic benefits of the process are reduced to a certain extent. At the same time, ruthenium has poor high temperature resistance and is easily deactivated at high temperatures of 360-390°C, especially when the temperature is higher than 400°C. At present, researchers in this field are committed to improving ruthenium-based catalysts by further improving their activity and high-temperature thermal stability and reducing costs to achieve wider commercialization. Sumitomo Chemical's CN101223104A uses rutile titanium dioxide and α-alumina mixed in different proportions as carriers to prepare a supported RuO ₂ catalyst. The activity of this catalyst decreases continuously during the hydrogen chloride oxidation process, and the reaction temperature needs to be gradually increased to increase the hydrogen chloride conversion rate. At the same time, the activity decreases at high temperatures.

The Deacon reaction temperature is generally between 280-420℃, which is in a relatively high thermal environment. At the same time, since the reaction is an exothermic reaction, the catalyst needs to have not only good thermal conductivity and thermal stability, but also a low specific surface area, such as ^10-50m2 /g. Due to the thermal effect of the material, the material with a large specific surface area will decrease in specific surface area as the grain grows at high temperature and the pore structure changes. This is very unfavorable for the catalyst after loading the active component, which will cause the activity to decrease and accelerate deactivation.

The grain size and dispersion of the active components of the catalyst greatly affect the activity of the reaction. The smaller the metal particle size, the higher the dispersion of the metal can be. At the same time, it can have a better combination with the carrier, the grains are not easy to grow, and have better thermal stability. Usually, when preparing catalysts, high specific surface area materials are selected as carriers, which is conducive to the loading of active metals and higher dispersion. Due to the limitations of reaction conditions, the Deacon reaction requires a carrier with good thermal stability. Selecting a material with a smaller specific surface area as a carrier will make it difficult to achieve high dispersion of the active component ruthenium, which not only affects the activity of the catalyst, but also increases the amount of ruthenium used, which is not conducive to cost control.

Summary of the invention

The purpose of the present application is to provide a catalyst for the oxidation of hydrogen chloride to produce chlorine, wherein the active component ruthenium is in a highly dispersed state; and to provide a ruthenium catalyst with a high carrier thermal conductivity; and a method for preparing the catalyst and using the catalyst to catalytically oxidize hydrogen chloride to chlorine by oxygen.

On the one hand, a method for preparing a highly dispersed ruthenium catalyst for preparing chlorine by hydrogen chloride oxidation of the present application comprises the following steps:

(1) dispersing the ruthenium-containing active component by a surfactant to prepare an impregnation solution;

(2) contacting and adhering the impregnation solution to a composite support of titanium oxide and aluminum oxide, drying and then calcining the mixture, wherein the calcination temperature is 150-700° C. and the time is 1-24 hours;

(3) Cooling, washing and drying.

In this field, there are relevant studies on the composition of the ruthenium active component loading carrier, the specific surface area of the carrier, and parameters such as temperature and time in the production and preparation process, but there is no exploration on the dispersibility of the ruthenium active component, the size of the ruthenium grains or the pretreatment of the impregnation solution.

Wherein, the surfactant is selected from any one or more combinations of hydrophilic nonionic surfactants including but not limited to polyoxyethylene nonionic surfactants, polyethylene glycol, polysorbate, etc. More specifically, the surfactant is selected from any one or more combinations of T-80 (Tween-80), OP-10 (alkylphenol polyoxyethylene ether), PEG-400 (polyethylene glycol 400); T-80 is more preferably used as the surfactant. By adding a surfactant, a coating and isolation between the active component ruthenium particles is formed, and the ruthenium component will not produce serious agglomeration between the ruthenium particles during the impregnation adsorption or drying stage, so that the precious metal ruthenium (Ru) as the active component is in a highly dispersed state, thereby inhibiting the agglomeration caused by the growth of metal particles due to calcination.

Preferably, the amount of the surfactant used is 1-10 times the mass of the metal element in the ruthenium active component, and more preferably 1-5 times.

The ruthenium active component described in the present application is derived from but not limited to any one or more combinations of the following components: RuCl ₃ , RuCl ₃ ·xH ₂ O, RuBr ₃ , RuBr ₃ ·xH ₂ O; chlororuthenates, such as K ₃ RuCl ₆ , (RuCl ₃ ) ^3- , K ₂ RuCl ₆ ; chlororuthenate hydrates, such as [RuCl ₅ (H ₂ O) ₄ ] ^2- , [RuCl ₂ (H ₂ O) ₄ ] ⁺ ; ruthenates, such as K ₂ RuO ₄ or Na ₂ RuO ₄ ; ruthenium oxychloride, such as Ru ₂ OCl ₄ , Ru ₂ OCl ₅ , Ru ₂ OCl ₆ ; ruthenium oxychloride salts, such as K ₂ Ru ₂ OCl ₁₀ , Cs ₂ Ru ₂ OCl ₄ ; ruthenium ammine complexes, such as [Ru(NH ₃ ) ₆ ] ²⁺ , [Ru(NH ₃ ) ₆ ] ³⁺ , [Ru(NH ₃ ) ₅ H ₂ O] ²⁺ ; ruthenium chloride amine complexes, such as [Ru(NH ₃ ) ₅ Cl] ²⁺ , [Ru(NH ₃ ) ₆ ]Cl ₂ , [Ru(NH ₃ ) ₆ ]Cl ₃ ; ruthenium bromide amine complexes, such as [Ru(NH ₃ ) ₆ ]Br ₃ ; ruthenium acetylacetonate; carbonyl ruthenium, such as Ru(CO) ₅ or Ru(CO) ₁₂ ; organic acid salts of ruthenium, such as [Ru ₃ O(OCOCH ₃ ) ₆ (H ₂ O) ₃ ]OCOCH ₃ , Ru ₂ (RCOO) ₄ Cl (wherein R is a hydrocarbon group containing 1 to 3 carbon atoms); nitrosyl ruthenium nitrate, such as K ₂ [RuCl ₆ (NO)], [Ru(NH ₃ ) ₅ (NO)]Cl ₃ , [Ru(OH)(NH ₃ ) ₄ (NO)](NO ₃ ) ₂ , Ru(NO)(NO ₃ ) ₃ ; ruthenium phosphorus complexes, etc. Preferably, the ruthenium active component is selected from ruthenium trichloride or its hydrate, ruthenium tribromide or its hydrate. The more preferred compound is ruthenium trichloride hydrate.

In the present application, the active precious metal component ruthenium element accounts for 0.1-10wt% of the ruthenium catalyst, more preferably 0.5-5wt%, and most preferably 1-3wt%. A lower content of the active component will result in insufficient catalyst activity, while a higher content will increase the catalyst cost.

Preferably, the impregnation method in step (2) is any one of equal volume impregnation, excess impregnation and spray impregnation.

Preferably, the titanium oxide is preferably rutile titanium dioxide. The aluminum oxide is selected as α-Al ₂ O ₃ and has a thermal conductivity of not less than 23W/m·℃. By forming a composite carrier with rutile titanium dioxide and α-Al ₂ O ₃ having a high thermal conductivity, the carrier prepared after molding has high thermal conductivity and more macropores, thereby improving the dissipation of heat generated during the reaction process, preventing the growth of ruthenium active component grains due to excessively high reaction temperature and the formation of agglomerates, and at the same time, it is also conducive to achieving a high dispersion state of ruthenium active components. Most carriers in the prior art still have a certain degree of reaction inertness, and the specific surface area is not easy to improve, resulting in difficulty in the adsorption of metallic ruthenium. The composite carrier provided in the present application has significantly improved adsorption of metallic ruthenium under the pretreatment of the above-mentioned surfactant.

The composite carrier is prepared by a molding process, and its shape includes any one or more combinations of powder, spherical, columnar, special-shaped, and honeycomb.

The catalyst prepared after carrier impregnation and molding has a specific surface area of ^10-50m2 /g, ruthenium grains of 1-10nm, and a ruthenium metal surface area of ^120-410m2 /(g·Ru), which is highly dispersed. At the same time, the preparation process enhances thermal stability, which is conducive to extending service life and meeting the requirements of industrial catalysis and production.

The present application improves the preparation process and prepares a catalyst with higher ruthenium dispersion than existing catalysts on a carrier with a lower specific surface area. According to tests, the currently industrialized 1.5% Ru content catalyst has a surface area of about ^130-200m2 /(g·Ru), while the surface area of the catalyst prepared by the present application method with the same 1.5% Ru content can reach ^200-340m2 /(g·Ru). The high dispersion increases the effective utilization rate of ruthenium atoms, greatly improves the catalyst activity, and can achieve higher activity under the condition of lower metal loading.

Preferably, the present application loads the ruthenium active component after the carrier forming process, and the calcination after loading does not cause obvious sintering, which can effectively prevent the growth of metal grains, thereby preparing a catalyst with high dispersion.

The carrier material selected in the present application has the characteristics of acid and alkali resistance and stable high temperature performance. The selection of high thermal conductivity materials is conducive to the timely removal of reaction heat, and the appropriate specific surface area is conducive to the dispersion of active metals. The ruthenium catalyst provided in the present application is used for the preparation of chlorine by hydrogen chloride oxidation, and has good catalytic activity and high catalytic activity at low temperatures. The ruthenium active component is added by a surfactant to form an impregnation solution, which is conducive to improving the adsorption of active metals by the carrier and improving the dispersion of metallic ruthenium. At the same time, the migration and agglomeration of ruthenium components can be prevented in subsequent drying, calcination and other processes. High dispersion means that the effective utilization rate of metal atoms is increased, with high activity, while maintaining a high conversion rate, reducing the metal content, which is conducive to reducing the cost of the catalyst.

On the other hand, the present application provides a ruthenium catalyst, comprising a porous carrier and a Ruthenium active component; the porous carrier is derived from titanium oxide, high thermal conductivity ceramics and additive mixture, and the high thermal conductivity ceramics are selected from any one or more combinations of Si ₃ N ₄ , BN and SiC.

The high thermal conductivity ceramics described in the present application are required to have good thermal conductivity and suitable specific surface area, including but not limited to any one or more combinations of Si ₃ N ₄ , BN, and SiC. More specifically, they refer to inorganic ceramic materials with a thermal conductivity of not less than 30 W/m·℃, because the thermal conductivity of α-Al ₂ O ₃ is only 23 W/m·℃, and the thermal conductivity of other crystalline Al ₂ O ₃ generally does not exceed 23 W/m·℃. By improving the thermal conductivity and surface area of the carrier component, the conversion rate of the carrier in a high temperature environment will be significantly improved. More preferably, the high thermal conductivity ceramics are selected from materials with a high thermal conductivity of more than 50 W/m·℃, such as β-SiC, β-Si ₃ N ₄ , and hexagonal BN. Among them, β-SiC has a thermal conductivity of 146-270w/m·℃ and a specific surface area of more than 20m ² /g, β-Si ₃ N ₄ has a thermal conductivity of 30-155w/m·℃ and a specific surface area of more than 40m ² /g, and hexagonal BN has a thermal conductivity of more than 79.54w/m·℃ and a specific surface area of more than 50m ² /g.

In addition, the titanium oxide is preferably rutile titanium dioxide or titanium dioxide containing rutile. In the present application, by compounding rutile titanium dioxide with a high thermal conductivity material, the carrier prepared after molding has high thermal conductivity and a large number of macropores, thereby improving the dissipation of heat generated during the reaction process, preventing the growth of ruthenium active component grains due to excessively high reaction temperature and the formation of agglomerates, which is beneficial to prolonging the service life of the catalyst.

The ruthenium active component described in the present application is derived from but not limited to any one or more combinations of the following components: RuCl ₃ , RuCl ₃ ·xH ₂ O, RuBr ₃ , RuBr ₃ ·xH ₂ O; chlororuthenates, such as K ₃ RuCl ₆ , (RuCl ₃ ) ^3- , K ₂ RuCl ₆ ; chlororuthenate hydrates, such as [RuCl ₅ (H ₂ O) ₄ ] ^2- , [RuCl ₂ (H ₂ O) ₄ ] ⁺ ; ruthenates, such as K ₂ RuO ₄ or Na ₂ RuO ₄ ; ruthenium oxychloride, such as Ru ₂ OCl ₄ , Ru ₂ OCl ₅ , Ru ₂ OCl ₆ ; ruthenium oxychloride salts, such as K ₂ Ru ₂ OCl ₁₀ , Cs ₂ Ru ₂ OCl ₄ ; ruthenium ammine complexes, such as [Ru(NH ₃ ) ₆ ] ²⁺ , [Ru(NH ₃ ) ₆ ] ³⁺ , [Ru(NH ₃ ) ₅ H ₂ O] ²⁺ ; ruthenium chloride amine complexes, such as [Ru(NH ₃ ) ₅ Cl] ²⁺ , [Ru(NH ₃ ) ₆ ]Cl ₂ , [Ru(NH ₃ ) ₆ ]Cl ₃ ; ruthenium bromide amine complexes, such as [Ru(NH ₃ ) ₆ ]Br ₃ ; ruthenium acetylacetonate; carbonyl ruthenium, such as Ru(CO) ₅ or Ru(CO) ₁₂ ; organic acid salts of ruthenium, such as [Ru ₃ O(OCOCH ₃ ) ₆ (H ₂ O) ₃ ]OCOCH ₃ , Ru ₂ (RCOO) ₄ Cl (wherein R is a hydrocarbon group containing 1 to 3 carbon atoms); ruthenium-nitrosyl complexes, such as K ₂ [RuCl ₆ (NO)], [Ru(NH ₃ ) ₅ (NO)]Cl ₃ , [Ru(OH)(NH ₃ ) ₄ (NO)](NO ₃ ) ₂ , Ru(NO)(NO ₃ ) ₃ ; ruthenium phosphorus complexes, etc. Preferably, the ruthenium active component is selected from ruthenium trichloride or its hydrate, ruthenium tribromide or its hydrate. A more preferred compound is ruthenium trichloride hydrate.

In the present application, the active precious metal component ruthenium element accounts for 0.1-10wt% of the ruthenium catalyst, preferably 0.5-5wt%, more preferably 1-3%. A lower content of the active component will result in insufficient catalyst activity, while a higher content will increase the catalyst cost.

In order to obtain the ruthenium catalyst, the present application provides a corresponding preparation method, which specifically comprises the following steps:

(1) mixing titanium oxide, a high thermal conductivity material and an additive to obtain a mixed powder;

(2) the mixed powder is mixed with water, shaped, dried, and subjected to a first calcination to obtain a high-strength carrier;

(3) preparing a ruthenium active component precursor solution into an impregnation solution;

(4) impregnating the impregnation solution onto a high-strength carrier, drying, and obtaining the ruthenium catalyst after a second calcination;

The high thermal conductivity material is selected from any one or more combinations of Si ₃ N ₄ , BN, and SiC. More preferably, the high thermal conductivity ceramic is selected from materials with a high thermal conductivity greater than 50 W/m·°C, such as β-SiC, β-Si ₃ N ₄ , and hexagonal BN.

The present application utilizes an impregnation solution made from a ruthenium active component precursor to load onto a high-strength carrier. The acid resistance, alkali resistance, and high thermal stability of the carrier must be considered, and selecting a suitable specific surface area is conducive to the dispersion of the active metal.

The shape of the carrier is selected from, but not limited to, spherical, cylindrical, honeycomb, special-shaped structures, and the like.

A suitable molding process will provide a larger specific surface area for reaction. The molding method comprises subjecting a powder carrier to a molding process to obtain solid particles, and then subjecting the powder carrier to a drying and calcining process to obtain a molded carrier. The molding process is selected from, but is not limited to, tableting, ball rolling, extrusion, spray molding, and oil column molding. Extrusion, tableting, and ball rolling molding processes are preferred, and extrusion molding is more preferred. As a preferred extrusion molding process, the high-strength carrier particles formed by extrusion are 1-3 mm in diameter and 2-7 mm in length.

Preferably, the auxiliary agent in step (1) accounts for 1-10wt% of the total weight of the mixed powder, and the titanium oxide in step (2) accounts for 20-80% of the total weight of the carrier after calcination. More preferably, the titanium oxide accounts for 30-60% of the total weight of the carrier, and the auxiliary agent accounts for 1-10wt% of the total weight of the mixed powder. The titanium oxide is preferably rutile titanium dioxide.

Preferably, the auxiliary agent is selected from any one or more combinations of polyvinyl alcohol, cellulose, starch, sesbania powder, and synthetic resin, preferably cellulose or sesbania powder. Wherein, the cellulose is selected from any one or more combinations including but not limited to methyl cellulose, hydroxyethyl cellulose, and hydroxypropyl methyl cellulose. The auxiliary agents are all organic binders, which help the mixed powder to improve the molding effect in the molding process; and form pores after drying and calcining to increase the specific surface area.

Preferably, the amount of water added in step (2) is 20-50% of the mass of the mixed powder. The drying in step (2) is performed at 60-120° C. for 3-24 hours.

Those skilled in the art may make adaptive adjustments based on the desired pore morphology and specific surface area of the selected additives and carriers, all of which are within the scope of protection of this application.

The first calcination is to obtain a high-strength carrier for loading the ruthenium active component, mainly to optimize the porous morphology and physical properties of the carrier, while the second calcination is after step (3), and the thermal stability of the ruthenium active component must be considered. To this end, the first calcination is calcined at 300-800°C for 1-24h, preferably calcined at 400-700°C for 3-6h. The second calcination is calcined at 200-700°C for 1-24h, preferably calcined at 250-600°C for 2-6h, and then naturally cooled to room temperature.

After step (4), the product may be further washed with water to remove ash, and then dried at 60-120° C. to obtain a ruthenium catalyst product.

The ruthenium catalyst of the present application should have a suitable specific surface area so as to maintain the catalytic activity and stability. Too high an area will cause insufficient stability. For this reason, the specific surface area of the carrier described in step (2) is controlled at ^10-50m2 /g, which will cause the carrier to have difficulty in adsorbing active components, especially metal ruthenium, making it difficult for metal Ru to be evenly distributed on the carrier, resulting in low dispersion. For this reason, the impregnation solution also includes a surfactant, which is selected from any one of T-80 (Tween-80), OP-10 (alkylphenol polyoxyethylene ether), and PEG-400 (polyethylene glycol 400). The amount of the surfactant is 1-10 times the mass of the metal element in the ruthenium active component, preferably 1-5 times. By treating the impregnation solution with a surfactant, the migration and agglomeration of the ruthenium component can be prevented during the drying and calcining process, and finer ruthenium grains can be generated, which is more conducive to improving the dispersion of ruthenium.

The ruthenium catalyst obtained after drying and two calcinations has a specific surface area of ^10-50m2 /g, a pore size of 0.01-6um, a strength of 120-200N/cm when the diameter is 1.5-3mm, and a thermal conductivity of 0.6-2.0W/m·℃ at 350℃ based on the hot wire method.

The ruthenium catalyst provided in this application has high low-temperature activity. The industrial production of hydrogen chloride oxidation to produce chlorine requires a catalytic temperature between 300-420°C, wherein a conversion rate of 50-80% can be basically guaranteed in the low temperature range of 300-330°C, and a conversion rate of not less than 90% can be achieved in the high temperature range of 360-420°C. The ruthenium catalyst provided in this application can achieve a conversion rate of not less than 90% in the low temperature range.

The catalyst of the present application does not need to be activated before use, and the catalyst use conditions are: reaction pressure 0.1-0.5Mpa; reaction temperature 200-500°C, preferably 300-400°C; hydrogen chloride space velocity 1-5m ³ /kg-cat·h, oxygen to hydrogen chloride molar ratio 1:(4-1). The obtained gas flow is passed through potassium iodide aqueous solution, and the sample is measured by iodine titration and neutralization titration to measure the amount of chlorine generated and the amount of unreacted hydrogen chloride, thereby calculating the conversion rate.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a TEM image of the ruthenium catalyst of Example 1-1.

FIG. 2 shows the particle size distribution of the ruthenium catalyst of Example 1-1.

FIG3 is a TEM image of the ruthenium catalyst of the control group 1-1.

FIG. 4 shows the particle size distribution of the ruthenium catalyst of the control group 1-1.

DETAILED DESCRIPTION

The present application is described in detail below based on examples. It should be noted that the embodiments described below are exemplary for experienced people and are intended to be used to explain the present application, but the present application is not limited to these examples. Unless otherwise specified, all percentage units should be understood as mass percentages.

The surface area of ruthenium metal is tested by CO pulse adsorption method: the specific operation is to use Micrometric Chemisorb chemical adsorption instrument to perform CO pulse adsorption characterization analysis on the catalyst sample. 50 mg of sample is filled into a U-shaped quartz tube, and a certain amount of quartz wool is placed at the bottom; Ar gas containing _H2 is introduced and the temperature is raised at 5℃/min. The temperature was raised to 350°C at a rate, and the pretreatment was carried out for 3 hours at this temperature and atmosphere. The temperature was lowered to room temperature, and after the baseline was stabilized, a pulse of Ar containing CO was adsorbed until CO was saturated. After the CO adsorption amount was obtained, the ruthenium metal surface area was calculated according to the atomic ratio of Ru/CO = 1:1. The ruthenium metal surface area in the embodiment was converted into the surface area per gram of metal ruthenium, and the unit was ^m2 /(g·Ru). The ruthenium metal surface area test method in all embodiments was carried out under the same conditions.

Thermal conductivity determination: There are different methods for determining thermal conductivity, and the results obtained by different test methods may also be different. This is related to the particle size of the test material, the loading speed, the loading method, etc. Even if the same test scheme is used, the results obtained by loading the same material with different particle sizes are different. In order to highlight the high thermal conductivity of the catalyst of the present application and its comparability with the control group, the following examples and the control group were tested under the same conditions.

The thermal conductivity of the catalyst is tested using the hot wire method, which assumes that there is an ideal infinitely thin and infinitely long linear heat source in the material. The temperature rise of the hot wire over time is a function of the heating power and the thermal conductivity of the material being tested. The temperature rise of the hot wire in the material being tested is measured using a thermocouple. The thermal conductivity calculation formula for the tested sample is:

In the formula, k is the thermal conductivity of the material being tested; d(Inτ)/dθ is the logarithm of time-temperature change rate; Q is the heat flow rate transferred from the hot wire to the sample being tested. From the formula, we can know that as long as we know the heat flow rate Q transferred from the hot wire to the sample being tested and the temperature change rate at the selected point with time, we can calculate the thermal conductivity of the sample being tested.

Example 1-1

Weigh 50 grams of a strip composite carrier composed of rutile titanium dioxide and α-alumina (titanium dioxide accounts for 50%) with a diameter of 3 mm and a length of 5 mm, a strength of 120 N/cm, and a specific surface area of 30 m ² /g.

To a ruthenium chloride solution containing 0.75 g of Ru, add 1.5 g of Tween-80 to prepare 25 ml for impregnation, and dry at 60°C for 12 hours to obtain a dried catalyst.

The dried catalyst was dry-calcined in air at 200°C for 5 hours, the product was washed with water, and dried at 80°C to obtain the catalyst product.

Theoretical calculations show that the mass percentage of the catalyst component is 1.5% Ru/(TiO ₂ :Al ₂ O ₃ =50:50), and the measured value of the surface area of ruthenium metal is 306.7 ^{m 2} /(g·Ru).

As shown in Figure 1, the metal particle size was observed using a transmission electron microscope (TEM). As shown in Figure 2, the average particle size of the ruthenium, the active component of the catalyst prepared by this method, was about 1.21 nm.

Example 1-2

Weigh 50 grams of a strip composite carrier composed of rutile titanium dioxide and α-alumina (titanium dioxide accounts for 30%) with a diameter of 3 mm and a length of 5 mm, a strength of 130 N/cm, and a specific surface area of 25 m ² /g.

Add 0.5 g of Tween-80 to a ruthenium nitrate solution containing 0.5 g of Ru to make 25 ml for impregnation. and drying at 80°C for 6 hours to obtain a dried catalyst;

The dried catalyst was dry-calcined in air at 250°C for 4 hours; the product was washed with water and dried at 90°C to obtain the catalyst product.

Theoretically calculated catalyst component mass percentage is: 1.0%Ru/(TiO ₂ :Al ₂ O ₃ =30:70), and the measured value of ruthenium metal surface area is 281.0m ² /(g·Ru).

Examples 1-3

Weigh 50 grams of a strip composite carrier composed of rutile titanium dioxide and α-alumina (titanium dioxide accounts for 70%) with a diameter of 3 mm and a length of 5 mm, a strength of 138 N/cm, and a specific surface area of 30 m ² /g.

A ruthenium chloride solution containing 1.5 grams of Ru was added with 3.8 grams of OP-10 to prepare 25 ml for impregnation, and then dried at 80°C for 10 hours to obtain a dried catalyst.

The dried catalyst was dry-calcined in air at 350°C for 3 hours; the product was washed with water and dried at 100°C to obtain the catalyst product.

Theoretical calculations show that the mass percentage of the catalyst component is 3.0% Ru/(TiO ₂ :Al ₂ O ₃ =70:30), and the measured value of the surface area of ruthenium metal is 260.0 m ² /(g·Ru).

Examples 1-4

Weigh 50 grams of a strip composite carrier composed of rutile titanium dioxide and α-alumina (titanium dioxide accounts for 34%) with a diameter of 3 mm and a length of 5 mm, a strength of 142 N/cm, and a specific surface area of 50 m ² /g.

To a ruthenium chloride solution containing 1.0 g of Ru, add 2.0 g of Tween-80 to prepare 30 ml for impregnation, and dry at 80°C for 10 hours to obtain a dried catalyst.

The dried catalyst was dry-calcined in air at 350°C for 3 hours; the product was washed with water and dried at 110°C to obtain the catalyst product.

Theoretical calculations show that the mass percentage of the catalyst component is 2.0% Ru/(TiO ₂ :Al ₂ O ₃ =34:66), and the measured value of the surface area of ruthenium metal is 325.0 ^{m 2} /(g·Ru).

Examples 1-5

Weigh 50 grams of a strip composite carrier composed of rutile titanium dioxide and α-alumina (titanium dioxide accounts for 34%) with a diameter of 3 mm and a length of 5 mm, a strength of 130 N/cm, and a specific surface area of 29 m ² /g.

Take 50 grams of the calcined carrier, add 4.0 g of PEG-400 to 30 ml of ruthenium nitrate solution containing 0.75 g of Ru, and dry it at 100°C for 7 hours to obtain a dried catalyst.

The dried catalyst was dry-calcined in air at 400°C for 3 hours; the product was washed with water and dried at 120°C to obtain the catalyst product.

Theoretical calculations show that the mass percentage of the catalyst components is: 1.5% Ru/(TiO ₂ :Al ₂ O ₃ =34:66), ruthenium metal The measured value of the surface area is 326.7 ^{m 2} /(g·Ru).

Examples 1-6

Weigh 50 grams of a strip composite carrier composed of rutile titanium dioxide and α-alumina (titanium dioxide accounts for 80%) with a diameter of 3 mm and a length of 5 mm, a strength of 150 N/cm, and a specific surface area of 18 m ² /g.

Take 50 g of the calcined carrier, add 5.0 g of PEG-400 to a 30 ml solution of ruthenium nitrate nitrate containing 0.4 g of Ru, and dry it at 110°C for 6 hours to obtain a dried catalyst.

The dried catalyst was dry-calcined in air at 500°C for 3 hours; the product was washed with water and dried at 120°C to obtain the catalyst product.

Theoretical calculations show that the mass percentage of the catalyst component is 0.8% Ru/(TiO ₂ :Al ₂ O ₃ =80:20), and the measured value of the surface area of ruthenium metal is 297.5 ^{m 2} /(g·Ru).

Examples 1-7

Weigh 50 grams of a strip composite carrier composed of rutile titanium dioxide and α-alumina (titanium dioxide accounts for 50%) with a diameter of 3 mm and a length of 5 mm, a strength of 150 N/cm, and a specific surface area of 18 m ² /g.

Take 50 g of the calcined carrier, add 2.0 g of Tween-80 into 30 ml of potassium oxyruthenate chloride solution containing 0.5 g of Ru, and dry it at 110°C for 6 hours to obtain a dried catalyst.

The dried catalyst was dry-calcined in air at 400°C for 3 hours; the product was washed with water and dried at 120°C to obtain the catalyst product.

Theoretical calculations show that the mass percentage of the catalyst component is 1.0% Ru/(TiO ₂ :Al ₂ O ₃ =50:50), and the measured value of the surface area of ruthenium metal is 300.0 m ² /(g·Ru).

Examples 1-8

Weigh 50 grams of a strip composite carrier composed of rutile titanium dioxide and α-alumina (titanium dioxide accounts for 34%) with a diameter of 3 mm and a length of 5 mm, a strength of 150 N/cm, and a specific surface area of 29 m ² /g.

Take 50 grams of the calcined carrier, add 3.0 g of Tween-80 to a potassium chlororuthenate solution containing 0.75 g of Ru to make 30 ml for impregnation, and dry it at 110°C for 6 hours to obtain a dried catalyst.

The dried catalyst was dry-calcined in air at 450°C for 3 hours; the product was washed with water and dried at 120°C to obtain the catalyst product.

Theoretical calculations show that the mass percentage of the catalyst component is 1.5% Ru/(TiO ₂ :Al ₂ O ₃ =34:66), and the measured value of the surface area of ruthenium metal is 286.7 ^{m 2} /(g·Ru).

Examples 1-9

Weigh 50 grams of a strip composite carrier composed of rutile titanium dioxide and α-alumina (titanium dioxide accounts for 34%) with a diameter of 3 mm and a length of 5 mm, a strength of 150 N/cm, and a specific surface area of 29 m ² /g.

Take 50 grams of the calcined carrier, add 3.0 g of OP-10 to 30 ml of ruthenium ammine complex solution containing 1.0 g of Ru for impregnation, and dry it at 110°C for 6 hours to obtain a dried catalyst.

The dried catalyst was dry-calcined in air at 350°C for 3 hours; the product was washed with water and dried at 120°C to obtain the catalyst product.

Theoretical calculations show that the mass percentage of the catalyst component is 2% Ru/(TiO ₂ :Al ₂ O ₃ =50:50), and the measured value of the surface area of ruthenium metal is 305.0 m ² /(g·Ru).

Examples 1-10

Weigh 50 grams of a strip composite carrier composed of rutile titanium dioxide and α-alumina (titanium dioxide accounts for 34%) with a diameter of 3 mm and a length of 5 mm, a strength of 150 N/cm, and a specific surface area of 27 m ² /g.

Take 50 grams of the calcined carrier, add 1.5 g of OP-10 to a ruthenium-ammine complex solution containing 0.5 g of Ru to make 30 ml for impregnation, and dry it at 110°C for 6 hours to obtain a dried catalyst.

The dried catalyst was dry-calcined in air at 300°C for 3 hours; the product was washed with water and dried at 120°C to obtain the catalyst product.

Theoretical calculations show that the mass percentage of the catalyst component is: 1%Ru/(TiO ₂ :Al ₂ O ₃ =50:50), and the measured value of the surface area of ruthenium metal is 410.0m ² /(g·Ru).

Control group 1-1

According to the preparation method disclosed in Example 4 of Chinese invention patent CN1245773A, a ruthenium catalyst was prepared as control group 1. The specific steps are as follows: 3.23 grams of commercially available ruthenium oxide hydrate (RuCl ₃ ·nH ₂ O, Ru content 37.3%) was dissolved in 21.9g of pure water, and stirred to obtain an aqueous solution of ruthenium chloride. The obtained aqueous solution was added dropwise to 40.0 grams of titanium oxide carrier to impregnate ruthenium chloride. The supported substance was dried at 60°C in air for 2 hours to obtain titanium oxide supported ruthenium chloride. Then, the obtained solid was heated from room temperature to 350°C in air for about 1 hour, and calcined at this temperature for 3 hours to obtain a spherical solid. 0.5L of pure water was added to the obtained solid, stirred, and then placed for 30 minutes and washed by filtering. This operation was repeated 10 times. The washing time was about 7 hours. The washed substance was dried at 60°C in air for 4 hours to obtain 41.1 grams of gray-black supported ruthenium oxide catalyst.

The calculated value of the ruthenium content of the control group 1-1 is 2.9% Ru/TiO ₂ , and the measured value of the ruthenium metal surface area is 162.0 m ² /(g·Ru). The metal particle size was observed by transmission electron microscopy (TEM), as shown in Figure 3. Figure 4 shows that the average particle size of the ruthenium catalyst prepared by this technology is 2.09 nm.

Control group 1-2

According to the preparation method disclosed in Example 18 of Chinese invention patent CN1245773A, a ruthenium catalyst was prepared as control group 2. The specific steps are as follows: 2.03 g of commercially available ruthenium oxide hydrate (RuCl ₃ ·nH ₂ O, Ru content 37.3%) was dissolved in 14.6 g of pure water, and stirred to obtain a ruthenium chloride aqueous solution. The obtained aqueous solution was added dropwise to 50.0 g of the ruthenium oxide hydrate. Ruthenium chloride is impregnated on a strip composite carrier composed of titanium-α-alumina (titanium oxide accounts for 50%). The supported material is dried at 60°C in air for 2 hours to obtain titanium oxide-α-alumina supported ruthenium chloride. Then, the obtained solid is heated from room temperature to 350°C in air for about 1 hour, and calcined at this temperature for 3 hours to obtain a spherical solid. 0.5L of pure water is added to the obtained solid, stirred, left for 30 minutes, and washed by filtration. Repeat this operation 5 times. The washing time is about 4 hours. The washed material is dried at 60°C in air for 4 hours to obtain 50.0 grams of gray-black supported ruthenium oxide catalyst. The calculated value of the metal ruthenium content of the control group 1-2 is 1.5%Ru/(TiO ₂ :Al ₂ O ₃ ＝50:50), and the tested value of the ruthenium metal surface area is 166.7m ² /(g·Ru).

Test Example 1-1

The activity of all examples and control group catalysts was tested in a fixed bed catalytic reactor; reactor type: quartz tube reactor, inner diameter 25mm; catalyst particle size is granular, dosage is 10g; main reaction conditions are: HCl at 0.76L/min, _O2 at 0.64L/min through the catalyst bed. The conversion rates at different temperatures are shown in Table 1 and Table 2. Examples 1-1 to 1-10 and control groups 1-1 and 1-2 were carried out under the same conditions.

Table 1. Dispersion of different catalysts and conversion of hydrogen chloride at different temperatures

Table 2. Hydrogen chloride conversion rate after 500 h operation of different catalysts

It can be seen from Table 1 and Table 2 that the overall activity of the catalyst prepared in the present application in catalyzing the oxidation of hydrogen chloride to produce chlorine is significantly better than that of the catalyst in the control group, especially the dispersion of the active components is much greater than that of the control group, indicating that the active components of the catalyst prepared in the present application have high dispersion and thus exhibit better activity. At the same time, the low content of metal loading is of great significance to cost reduction.

Example 2-1

Take 30g of rutile titanium dioxide, 70g of β-phase silicon carbide, and 2.0g of sesbania powder, knead them evenly, add 30g of water and knead for 40min, extrude and shape into strips with a diameter of 3mm, dry them in air at 60℃ for 12 hours to obtain a dried strip carrier, and cut the carrier into pieces with a length of about 5mm.

The dried carrier was dry-baked in air at 400° C. for 6 hours to obtain a calcined strip carrier.

50 g of the calcined carrier was taken and impregnated with 25 ml of RuCl ₃ ·3H ₂ O solution containing 0.15 g of Ru and 0.15 g of Tween-80, and dried at 60° C. for 12 hours to obtain a dried catalyst.

The dried catalyst was dry-calcined in air at 250°C for 6 hours, the product was washed with water, and dried at 80°C to obtain the catalyst product.

Theoretical calculations show that the mass percentage of the catalyst components is:

[RuO ₂ /(RuO ₂ +TiO ₂ +SiC)]*100＝0.39%

The mass percentage of metal ruthenium is:

[Ru/(RuO ₂ +TiO ₂ +SiC)]*100＝0.3%

The final catalyst strength was 120N/cm, the specific surface area was ^30m2 /g, the average pore size was 0.02um, and the catalyst was tested at 350℃. The test thermal conductivity is 1.60W/m·℃.

Example 2-2

Take 45g of rutile titanium dioxide, 55g of β-phase silicon carbide, and 5.0g of sesbania powder, knead them evenly, add 25g of water and knead for 40min, extrude and shape into strips with a diameter of 3mm, dry them in air at 60℃ for 12 hours to obtain a strip carrier after drying, and cut the carrier into pieces with a length of about 5mm.

The dried carrier was dry-baked in air at 500° C. for 4 hours to obtain a calcined strip carrier.

Take 50g of the calcined carrier, add 0.5g of Tween-80 to 0.25g of RuCl ₃ ·3H ₂ O solution to make 25ml for impregnation, and dry at 80°C for 6 hours to obtain a dried catalyst;

The dried catalyst was dry-baked in air at 280°C for 5 hours; the product was washed with water and dried at 90°C to obtain the catalyst product.

Theoretical calculations show that the mass percentage of the catalyst components is:

[RuO ₂ /(RuO ₂ +TiO ₂ +SiC)]*100＝0.65%

The mass percentage of metal ruthenium is:

[Ru/(RuO ₂ +TiO ₂ +SiC)]*100＝0.5%

The final catalyst has a strength of 130 N/cm, a specific surface area of 25 m ² /g, an average pore size of 0.04 um, and a thermal conductivity of 1.21 W/m·°C at 350°C.

Example 2-3

Take 33 grams of rutile titanium dioxide, 67 grams of β-phase silicon nitride, and 5.0 grams of hydroxyethyl cellulose, mix them evenly; weigh 28 grams of water and pour them into the mixture, knead for 40 minutes, extrude and shape into strips with a diameter of 3 mm, dry them in air at 90°C for 8 hours, and obtain a dried strip carrier, which is cut into 5 mm long;

The dried carrier was dry-calcined in air at 550° C. for 4 hours to obtain a calcined strip-shaped carrier.

50 g of the calcined carrier was taken and impregnated with 25 ml of RuCl ₃ ·3H ₂ O solution containing 0.76 g of Ru and added with 2.0 g of OP-10, and dried at 80° C. for 10 hours to obtain a dried catalyst.

The dried catalyst was dry-calcined in air at 300°C for 4 hours; the product was washed with water and dried at 100°C to obtain the catalyst product.

Theoretical calculations show that the mass percentage of the catalyst components is:

[RuO ₂ /(RuO ₂ +TiO ₂ +Si ₃ N ₄ )]*100＝1.97%

The mass percentage of metal ruthenium is:

[Ru/(RuO ₂ +TiO ₂ +Si ₃ N ₄ )]*100＝1.5%

The final catalyst strength is 138N/cm, the specific surface area is ^28m2 /g, the average pore size is 0.06um, and the thermal conductivity is 1.48W/m·℃ at 350℃.

Embodiment 2-4

Take 45g of rutile titanium dioxide, 55g of β-phase silicon nitride, and 4.0g of methyl cellulose, mix them evenly; weigh 35g of water and pour it into the mixture, knead for 40min, extrude and shape into a strip with a diameter of 3mm, dry it in air at 100℃ for 5 hours, and obtain a strip carrier after drying, which is cut into 5mm long pieces;

The dried carrier was dry-calcined in air at 650° C. for 4 hours to obtain a calcined strip-shaped carrier.

50 g of the calcined carrier was taken and impregnated with 30 ml of RuCl ₃ ·3H ₂ O solution containing 1.56 g of Ru and 6.0 g of Tween-80, and dried at 80° C. for 10 hours to obtain a dried catalyst.

The dried catalyst was dry-calcined in air at 400°C for 2 hours; the product was washed with water and dried at 110°C to obtain the catalyst product.

Theoretical calculations show that the mass percentage of the catalyst components is:

[RuO ₂ /(RuO ₂ +TiO ₂ +Si ₃ N ₄ )]*100＝3.95%

The mass percentage of metal ruthenium is:

[Ru/(RuO ₂ +TiO ₂ +Si ₃ N ₄ )]*100＝3.0%

The final catalyst strength is 142N/cm, the specific surface area is ^50m2 /g, the average pore size is 0.1um, and the thermal conductivity coefficient tested at 350℃ is 1.32W/m·℃.

Embodiment 2-5

Take 40g of rutile titanium dioxide, 60g of hexagonal boron nitride and 4.0g of hydroxypropyl methylcellulose and mix them evenly; weigh 28g of water and pour it into the mixture, knead for 40min, extrude and shape into strips with a diameter of 3mm, dry them in air at 120℃ for 5 hours, and obtain a strip carrier after drying, which is cut into 5mm length;

The dried carrier was dry-baked in air at 700° C. for 4 hours to obtain a calcined strip carrier.

Take 50 grams of the calcined carrier, add 4.0 g of PEG-400 to 30 ml of ruthenium nitrate solution containing 2.11 g of Ru, and dry it at 100°C for 7 hours to obtain a dried catalyst.

The dried catalyst was dry-calcined in air at 350°C for 4 hours to obtain the catalyst product.

Theoretical calculations show that the mass percentage of the catalyst components is:

[RuO ₂ /(RuO ₂ +TiO ₂ +BN)]*100=5.2%

The mass percentage of metal ruthenium is:

[Ru/(RuO ₂ +TiO ₂ +BN)]*100＝4.0%

The final catalyst strength is 118N/cm, the specific surface area is ^26m2 /g, the average pore size is 0.07um, and the thermal conductivity is 1.29W/m·℃ at 350℃.

Embodiment 2-6

Take 50g of rutile titanium dioxide, 50g of hexagonal boron nitride, and 4.0g of polyvinyl alcohol, mix them evenly; weigh 29g of water and pour it into the mixture, knead for 40min, extrude and shape into a strip with a diameter of 3mm, dry it in air at 110℃ for 5 hours, and obtain a strip carrier after drying, which is cut into a length of 5mm;

The dried carrier was dry-calcined in air at 750° C. for 4 hours to obtain a calcined strip-shaped carrier.

50 g of the calcined carrier was taken and impregnated with 30 ml of ruthenium nitrate solution containing 1.56 g of Ru and added with 7.5 g of PEG-400, and dried at 110° C. for 6 hours to obtain a dried catalyst.

The dried catalyst was dry-calcined in air at 500°C for 2 hours to obtain the catalyst product.

Theoretical calculations show that the mass percentage of the catalyst components is:

[RuO ₂ /(RuO ₂ +TiO ₂ +BN)]*100=3.95%

The mass percentage of metal ruthenium is:

[Ru/(RuO ₂ +TiO ₂ +BN)]*100＝3.0%

The final catalyst has a strength of 150 N/cm, a specific surface area of 22 m ² /g, an average pore size of 3 um, and a thermal conductivity of 1.20 W/m·°C at 350°C.

Embodiment 2-7

Take 60g of rutile titanium dioxide, 40g of β-phase silicon nitride, and 5.0g of starch, mix them evenly; weigh 25g of water and pour it into the mixture, knead for 40min, extrude and shape into strips with a diameter of 3mm, dry them in air at 110℃ for 5 hours, and obtain a strip carrier after drying, which is cut into 5mm length;

The dried carrier was dry-baked in air at 800°C for 3 hours to obtain a calcined strip carrier with a strength of 200 N/cm, a specific surface area of 34 m ² /g, and an average pore size of 6 um.

Take 50 g of the calcined carrier, add 2.5 g of Tween-80 to 30 ml of K ₂ RuCl ₆ solution containing 0.51 g of Ru, and dry it at 110°C for 6 hours to obtain a dried catalyst.

The dried catalyst was dry-calcined in air at 550°C for 5 hours; the product was washed with water and dried at 120°C to obtain the catalyst product.

Theoretical calculations show that the mass percentage of the catalyst components is:

[RuO ₂ /(RuO ₂ +TiO ₂ +Si ₃ N ₄ )]*100＝1.3%

The mass percentage of metal ruthenium is:

[Ru/(RuO ₂ +TiO ₂ +Si ₃ N ₄ )]*100＝1.0%

The final catalyst has a strength of 200 N/cm, a specific surface area of 18 m ² /g, an average pore size of 6 um, and a thermal conductivity of 1.22 W/m·°C at 350°C.

Embodiment 2-8

Take 50g of rutile titanium dioxide, 50g of hexagonal boron nitride, and 3.0g of hydroxyethyl cellulose, mix them evenly; weigh 25g of water and pour it into the mixture, knead for 40min, extrude and shape into strips with a diameter of 3mm, dry them in air at 110℃ for 5 hours, and obtain a strip carrier after drying, which is cut into 5mm length;

The dried carrier was dry-calcined in air at 600° C. for 4 hours to obtain a calcined strip carrier.

Take 50 g of the calcined carrier and add 0.5 g of PEG-400 to a [Ru(NH ₃ ) ₆ ]Cl ₂ solution containing 0.25 g of Ru. Prepare 30 ml of the solution for impregnation and dry it at 110°C for 6 hours to obtain a dried catalyst.

The dried catalyst was dry-calcined in air at 400°C for 3 hours to obtain the catalyst product.

Theoretical calculations show that the mass percentage of the catalyst components is:

[RuO ₂ /(RuO ₂ +TiO ₂ +BN)]*100=0.66%

The mass percentage of metal ruthenium is:

[Ru/(RuO ₂ +TiO ₂ +BN)]*100＝0.5%

The final catalyst strength is 143N/cm, the specific surface area is ^24m2 /g, the average pore size is 1.0um, and the thermal conductivity coefficient tested at 350℃ is 1.23W/m·℃.

Embodiment 2-9

Take 35 grams of rutile titanium dioxide, 65 grams of β-phase silicon carbide, and 10.0 grams of sesbania powder, mix them evenly; weigh 30 grams of water and pour it into the mixture, knead for 40 minutes, extrude and shape into a strip with a diameter of 3 mm, dry it in air at 110°C for 5 hours, and obtain a strip carrier after drying, which is cut into a length of 5 mm;

The dried carrier was dry-calcined in air at 650° C. for 4 hours to obtain a calcined strip-shaped carrier.

50 g of the calcined carrier was taken and impregnated with 30 ml of RuBr ₃ ·3H ₂ O solution containing 0.92 g of Ru and added with 2.7 g of OP-10, and dried at 110° C. for 6 hours to obtain a dried catalyst.

The dried catalyst was dry-calcined in air at 350°C for 2 hours; the product was washed with water and dried at 120°C to obtain the catalyst product.

Theoretical calculations show that the mass percentage of the catalyst components is:

[RuO ₂ /(RuO ₂ +TiO ₂ +SiC)]*100＝2.37%

The mass percentage of metal ruthenium is:

[Ru/(RuO ₂ +TiO ₂ +SiC)]*100＝1.8%

The final catalyst strength is 129N/cm, the specific surface area is ^20m2 /g, the average pore size is 0.6um, and the thermal conductivity coefficient tested at 350℃ is 1.45W/m·℃.

Embodiment 2-10

Take 60g of rutile titanium dioxide, 40g of β-phase silicon carbide, and 8.0g of sesbania powder, mix them evenly; weigh 26g of water and pour it into the mixture, knead for 40min, extrude and shape into a strip with a diameter of 3mm, dry it in air at 110℃ for 5 hours, and obtain a strip carrier after drying, which is cut into a length of 5mm;

The dried carrier was dry-calcined in air at 650° C. for 4 hours to obtain a calcined strip-shaped carrier.

50 g of the calcined carrier was taken and impregnated with 32 ml of RuCl ₃ ·3H ₂ O solution containing 0.4 g of Ru and added with 0.8 g of PEG-400, and dried at 110° C. for 6 hours to obtain a dried catalyst.

The dried catalyst was dry-calcined in air at 300°C for 3 hours; the product was washed with water until there was no chloride ion, and dried at 120°C to obtain the catalyst product.

Theoretical calculations show that the mass percentage of the catalyst components is:

[RuO ₂ /(RuO ₂ +TiO ₂ +Si ₃ N ₄ )]*100＝1.0%

The mass percentage of metal ruthenium is:

[Ru/(RuO ₂ +TiO ₂ +Si ₃ N ₄ )]*100＝0.8%

The final catalyst strength is 121N/cm, the specific surface area is ^27m2 /g, the average pore size is 0.09um, and the thermal conductivity is 1.28W/m·℃ at 350℃.

Example 2-11

Take 55 grams of rutile titanium dioxide, 45 grams of β-phase silicon nitride, and 3.0 grams of sesbania powder, mix them evenly; weigh 28 grams of water and pour them into the mixture, knead for 40 minutes, extrude and shape into strips with a diameter of 3 mm, dry them in air at 120°C for 4 hours, and obtain a dried strip carrier, which is cut into 5 mm long;

The dried carrier was dry-calcined in air at 750° C. for 4 hours to obtain a calcined strip-shaped carrier.

50 g of the calcined carrier was taken and impregnated with 28 ml of RuCl ₃ ·3H ₂ O solution containing 0.61 g of Ru and added with 1.8 g of OP-10, and dried at 120° C. for 6 hours to obtain a dried catalyst.

The dried catalyst was dry-calcined in air at 350°C for 3 hours; the product was washed with water and dried at 120°C to obtain the catalyst product.

Theoretical calculations show that the mass percentage of the catalyst components is:

[RuO ₂ /(RuO ₂ +TiO ₂ +Si ₃ N ₄ )]*100＝1.58%

The mass percentage of metal ruthenium is:

[Ru/(RuO ₂ +TiO ₂ +Si ₃ N ₄ )]*100＝1.2%

The final catalyst strength is 139N/cm, the specific surface area is ^42m2 /g, the average pore size is 0.04um, and the thermal conductivity coefficient tested at 350℃ is 1.22W/m·℃.

Example 2-12

Take 30g of rutile titanium dioxide, 60g of hexagonal boron nitride, and 3.0g of sesbania powder, mix them evenly; weigh 30g of water and pour it into the mixture, knead for 40min, extrude and shape into strips with a diameter of 3mm, dry them in air at 120℃ for 4 hours, and obtain a strip carrier after drying, which is cut into 5mm length;

The dried carrier was dry-baked in air at 600°C for 4 hours to obtain a strip-shaped carrier with a strength of 153 N/cm, a specific surface area of 25 m ² /g, and an average pore size of 0.9 um.

50 g of the calcined carrier was taken and impregnated with 28 ml of RuCl ₃ ·3H ₂ O solution containing 1.03 g of Ru and added with 1.0 g of PEG-400, and dried at 120° C. for 6 hours to obtain a dried catalyst.

The dried catalyst was dry-calcined in air at 280°C for 3 hours; the product was washed with water and dried at 120°C to obtain the catalyst product.

Theoretical calculations show that the mass percentage of the catalyst components is:

[RuO ₂ /(RuO ₂ +TiO ₂ +BN)]*100=2.63%

The mass percentage of metal ruthenium is:

[Ru/(RuO ₂ +TiO ₂ +BN)]*100＝2.0%

The final catalyst strength is 151N/cm, the specific surface area is ^25m2 /g, the average pore size is 0.03um, and the thermal conductivity coefficient tested at 350℃ is 1.52W/m·℃.

Control group 2-1

This example is based on the technical solution disclosed in Example 18 of Sumitomo Chemical Patent CN1272238C to prepare a supported ruthenium oxide catalyst:

Dissolve 2.03 g of commercially available ruthenium oxide hydrate (RuCl ₃ ·nH ₂ O, Ru content 37.3 wt%) in 14.6 g of pure water, and stir to obtain an aqueous solution of ruthenium chloride. Add the obtained aqueous solution dropwise to 50.0 g of a strip-shaped composite carrier composed of titanium oxide-α-alumina (titanium oxide accounts for 50%) to impregnate ruthenium chloride. Dry the supported material in air at 60°C for 2 hours to obtain titanium oxide-α-alumina supported ruthenium chloride. Add a mixed solution consisting of 10.5 g of 2 mol/L potassium hydroxide aqueous solution, 300 g of pure water, and 2.54 g of hydrazine hydrate to the obtained titanium oxide-α-alumina supported ruthenium chloride at room temperature, stir every 15 minutes, and immerse for 1 hour. Foaming can be observed in the solution during immersion. After standing for about 15 minutes until the foam disappears, add 0.5L of pure water after filtering, stir, stand for 30 minutes, and then filter. Repeat this 5 times. After that, remove the supernatant by decantation. Then add 100g of potassium chloride aqueous solution adjusted to 0.5mol/L, stir, stand for 30 minutes, and remove the supernatant by decantation. Repeat this operation 3 times. Then dry the washed material in air at 60℃ for 4 hours to obtain a gray spherical solid containing potassium chloride.

Then, the obtained solid was heated from room temperature to 350°C in air for about 1 hour, and calcined at this temperature for 3 hours to obtain a spherical solid. 0.5L of pure water was added to the obtained solid, stirred, and allowed to stand for 30 minutes and washed by filtering. This operation was repeated 5 times. The washing time was about 4 hours. The washed material was dried at 60°C in air for 4 hours to obtain 50.0 grams of gray-black supported ruthenium oxide catalyst.

The calculated value of the metal ruthenium content is 1.5%Ru/(TiO ₂ :Al ₂ O ₃ =50:50), and the tested thermal conductivity at 350°C is 0.57 W/m·°C.

Test Example 2-1

The activity of all catalysts in the examples was conducted in a fixed bed catalytic reactor; reactor type: quartz tube reactor, inner diameter 25 mm; catalyst particle size is original particles, dosage is 10 g; main reaction conditions: 0.1 MPa, HCl at 0.76 L/min, O ₂ at 0.64 L/min through the catalyst bed. The conversion rates at different temperatures are shown in Tables 3 and 4. Examples 2-1 to 2-12 and Control 2-1 were conducted under similar conditions:

Table 3. Thermal conductivity of catalysts in different embodiments and conversion of hydrogen chloride at different temperatures

Table 4. Conversion rate of catalysts in different embodiments after 500 h of operation

As can be seen from Tables 3 and 4, the overall activity of the catalysts prepared in Examples 2-1 to 2-12 is higher than that of the control group. In particular, the conversion rate in the high temperature range and the life of the catalyst at high temperatures are significantly improved.

The above is only a preferred implementation of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims (10)

A method for preparing a highly dispersed ruthenium catalyst for the oxidation of hydrogen chloride to produce chlorine, characterized by comprising: (1) dispersing the ruthenium-containing active component through a surfactant to prepare an impregnation solution, (2) contacting and adhering the impregnation solution to a composite support of titanium oxide and aluminum oxide, drying and then calcining, (3) cooling, washing with water, and drying, Or (1) titanium oxide, high thermal conductivity ceramic and additives are mixed to obtain a mixed powder, the mixed powder is mixed with water, shaped, dried, and subjected to a first calcination to obtain a high-strength carrier, wherein the high thermal conductivity ceramic is selected from any one or more of Si ₃ N ₄ , BN, and SiC, (2) a ruthenium active component precursor solution is prepared into an impregnation liquid, wherein the impregnation liquid also includes a surfactant, (3) the impregnation liquid is impregnated on the high-strength carrier, dried, and subjected to a second calcination to obtain the ruthenium catalyst; The surfactant is selected from any one or more of polyoxyethylene nonionic surfactant, polyethylene glycol, and polysorbate, and the amount of the surfactant is 1-10 times the mass of the metal element in the ruthenium-containing active component. The ruthenium catalyst has a specific surface area of ^10-50m2 /g, and the ruthenium element accounts for 0.1-10wt% of the ruthenium catalyst. The method for preparing a highly dispersed ruthenium catalyst for the oxidation of hydrogen chloride to produce chlorine according to claim 1, characterized in that: the surfactant is selected from any one or more of T-80, OP-10, and PEG-400; and/or the ruthenium active component is selected from any one or more combinations of ruthenium trichloride or its hydrate, ruthenium tribromide or its hydrate, chlororuthenate or its hydrate, ruthenate, ruthenium oxychloride, ruthenium oxychloride salt, ruthenium ammine complex, ruthenium chloride amine complex, ruthenium bromide amine complex, ruthenium acetylacetonate, carbonyl ruthenium, organic acid salt of ruthenium, ruthenium nitrosyl nitrate, ruthenium-nitrosyl complex, ruthenium phosphorus complex; and/or the auxiliary agent is selected from any one or more of polyvinyl alcohol, cellulose, starch, sesbania powder, and synthetic resin; the auxiliary agent is 1-10wt% of the mixed powder; and/or the titanium oxide is rutile titanium dioxide; And/or the aluminum oxide is α-Al ₂ O ₃ . The method for preparing a highly dispersed ruthenium catalyst for preparing chlorine by hydrogen chloride oxidation according to claim 1 is characterized in that: the impregnation method in the contact and attachment of the impregnation liquid is any one of equal volume impregnation, excess impregnation, and spray impregnation; and/or the contact and attachment of the impregnation liquid is completed at a temperature of 30-60°C; and/or the calcination temperature in the calcination after drying is 150-700°C, and the time is 1-24 hours. The method for preparing a highly dispersed ruthenium catalyst for preparing chlorine by hydrogen chloride oxidation according to claim 1 is characterized in that the shape of the composite carrier prepared by a molding process includes any one or more of powder, spherical, columnar, irregular, and honeycomb. The method for preparing a highly dispersed ruthenium catalyst for the oxidation of hydrogen chloride to produce chlorine according to claim 1, characterized in that the ruthenium element accounts for 0.3-5wt% of the ruthenium catalyst. The method for preparing a highly dispersed ruthenium catalyst for preparing chlorine by oxidation of hydrogen chloride according to claim 1 is characterized in that the particle size of the ruthenium crystal is 1-10 nm and the surface area of the metal ruthenium is 120-410 m ² /(g·Ru). The method for preparing a highly dispersed ruthenium catalyst for preparing chlorine by hydrogen chloride oxidation according to claim 1 is characterized in that the pore size of the ruthenium catalyst is 0.01-6um, and the strength is 120-200N/cm when the diameter is 1.5-3mm cylinder. The method for preparing a highly dispersed ruthenium catalyst for preparing chlorine by hydrogen chloride oxidation according to claim 1, characterized in that: the first calcination is calcined at 300-800° C. for 1-24 h; and/or the second calcination is calcined at 200-700° C. for 1-24 h, and then naturally cooled to room temperature. The method for preparing a highly dispersed ruthenium catalyst for preparing chlorine by hydrogen chloride oxidation according to claim 7 is characterized in that the thermal conductivity of the ruthenium catalyst at 350°C based on the hot wire method is 0.6-2.0 W/m·°C. A ruthenium catalyst, characterized in that: the ruthenium catalyst is prepared by the method described in any one of claims 1-9.