A method for preparing a hydrogen chloride to chlorine catalyst based on a modified alumina support

Abstract

This invention discloses a method for preparing a hydrogen chloride-to-chlorine catalyst based on a modified alumina support; the method is as follows: 1. Modification of the Al2O3 support. 2. Loading of the active component: This invention modifies the Al2O3 support using a simple and easy-to-operate method to increase the five-coordinated aluminum (Al) in the Al2O3 support. p Quantity; five-coordinated aluminum Al p It is an important metal anchoring point, and the five-coordinated aluminum Al on the carrier surface p It can serve as an important anchoring point at the metal-carrier interface, which is beneficial for the electronic interaction between the metal and Al2O3 defects. In subsequent impregnation and calcination, Al... p The stable binding with the active components allows Cu and CeVO4 to be highly dispersed on the Al2O3 support surface. Furthermore, Al... p The metal anchoring effect can enhance the interaction between the support and the active component, reduce the loss of the active component of the catalyst, and thus improve the high-temperature thermal stability, durability and anti-poisoning ability of the catalyst.

Description

Technical Field

[0001] This invention belongs to the field of chlorine production technology, specifically relating to a method for preparing a hydrogen chloride to chlorine catalyst based on a modified alumina support. Background Technology

[0002] Chlorine is widely used in new materials industries such as polyurethane, epoxy resin, chlorinated hydrocarbons, chlorinated polymers, and chlorinated rubber, as well as in new energy industries such as polysilicon manufacturing, and in industries such as papermaking, textiles, metallurgy, and petrochemicals. In industrial production involving chlorine, a large amount of chlorine is consumed while an equimolar amount of hydrogen chloride is produced as a byproduct, meaning that the utilization rate of chlorine resources in the chlorination reaction process is only about 50%. The total amount of hydrogen chloride produced as a byproduct in China's chlor-alkali industry has exceeded 5 million tons per year. With the large-scale expansion of chlorine-related products such as MDI, TDI, and methane chloride, and the development of the chlor-alkali industry, the utilization of this large amount of byproduct hydrogen chloride has become a common problem restricting the development of many industries, including polyurethane, chlor-alkali, organofluorine, pesticides, and pharmaceuticals. Converting the byproduct hydrogen chloride into raw material chlorine and re-involving it in the production process of chlorine-containing products transforms chlorine consumption from an open-loop consumption to a closed-loop cycle. Research has found that catalytic oxidation is currently the most effective solution, especially the catalytic oxidation method via the Deacon reaction, which has the greatest potential for industrial application due to its simple operation and low equipment cost.

[0003] In 1868, Deacon et al. first proposed using CuCl2 / pumice catalysts for the production of chlorine from hydrogen chlorination. Following this, extensive research was conducted on copper-based Deacon catalysts. This was the earliest research on copper-based catalysts for the production of chlorine from hydrogen chlorination. Subsequent studies have explored Deacon catalysts based on other elements. Currently, Deacon catalysts include ruthenium-based, cerium-based, chromium-based, and copper-based catalysts.

[0004] Japanese Patent JPA2008155199 discloses Sumitomo Chemical's large-scale application of the RuO2 / TiO2-SiO2 catalyst in the production of chlorine from hydrogen chloride. Using a fixed-bed reactor, under reaction conditions of 200–380 °C, ambient pressure, and HCl / O2 = 2 / 1, the hydrogen chloride conversion rate was maintained at 85–90%, and the catalyst operated stably for nearly 15,000 hours, demonstrating good performance in practical applications. However, ruthenium, as a precious metal, is expensive and has limited reserves, making it difficult to use as a sustainable catalyst active component.

[0005] Chinese patent CN1126637A discloses a catalyst for the production of chlorine by hydroxylation of chlorine with chromium oxide as the active component. This catalyst maintains a conversion rate of 76% after 1500 hours of reaction at a reactant temperature of 380℃ and an HCl / O2 ratio of 2 / 1. However, due to the toxicity of chromium-based catalysts, there are serious environmental pollution problems in practical applications, making industrial application impossible.

[0006] Chinese patent CN113856708A discloses a copper-based catalyst prepared by a co-precipitation method. The catalyst uses CuCl2 as the active component, Al2O3 as the support, and adds alkali metal K and rare earth metal Sm. The HCl / O2 ratio is 1 / 1, the reaction temperature is 330℃, the reaction pressure is 0.5 MPa, and the hydrogen chloride conversion rate is 88% after 120 hours of reaction.

[0007] Current research indicates that copper-based catalysts, modified with metals or additives, have achieved good stability and hydrogen chloride conversion rates. Furthermore, copper is inexpensive and abundant, leading researchers to conduct extensive studies on copper-based deacon catalysts and achieve significant progress. Copper-based catalysts have become one of the deacon catalysts with the greatest potential for industrial application.

[0008] Chinese patent CN101559374A discloses a method using silica gel and ReY molecular sieves as supports to load Cu, K, and Ce. Under conditions where the flow rates of hydrogen chloride and oxygen are both 200 mL / min, the catalyst dosage is 25 g, and the reaction temperature is 380 ℃, the conversion rate of hydrogen chloride is 83.6%, and the catalyst activity is improved. However, it does not fundamentally solve the problem of copper loss from the catalyst.

[0009] Chinese patent CN101125297A discloses a catalyst for loading copper chloride, potassium chloride, and cerium chloride onto an Al2O3 support treated with phosphoric acid, at an HCl / O2 ratio of 1:1, a reaction temperature of 400 °C, and a mass hourly space velocity (HHSV) of 0.8 h⁻¹ for the HCl feed. -1 The conversion rate of the product chlorine gas can reach 80.1%. The addition of phosphoric acid slows down the loss of active components, but there is still a relatively serious loss, which limits its industrial application.

[0010] Cu-based catalysts still have room for improvement. For example, a key issue hindering their industrial application is that copper readily volatilizes out of the reactor as low-boiling-point copper chloride, condensing and accumulating in low-temperature pipes or heat exchangers. Even small amounts of loss can easily lead to pipeline blockage and production interruptions in the presence of large amounts of catalyst. Therefore, further reduction of copper loss is necessary. Existing solutions to the loss of active components in copper-based catalysts mainly involve adding promoters or alkali metals. These solutions primarily focus on improving the active components, with little research on modifying or controlling the support to enhance the catalyst's thermal stability and catalytic performance. For supported copper-based catalysts used in hydrogen chlorination and oxidation, employing a suitable support can strengthen the interaction between Cu and the support, improving issues such as poor distribution of active components on the catalyst surface, narrow catalyst pores, and small Cu specific surface area.

[0011] Based on the above research background, it is necessary to develop a catalyst with high activity, low loss of active components, and high stability. Summary of the Invention

[0012] The problem this invention aims to solve is to address the issues existing in the copper-based catalysts for chlorination and hydrogenation to produce chlorine mentioned above. This invention proposes a catalyst support, a catalyst, and a method for preparing the catalyst for chlorination and hydrogenation to produce chlorine. The catalyst support is modified to improve the interaction between the active component and the support, thereby enhancing the thermal stability of the catalyst, reducing loss, and meeting the requirement for long-term stable operation of the catalyst under high-temperature conditions.

[0013] In a first aspect, the present invention provides a method for preparing a hydrogen chloride-to-chlorine catalyst based on a modified alumina support, comprising the following steps:

[0014] Step 1: Al2O3 support modification: Add Al2O3 to glacial acetic acid and seal; place in an oil bath at 120-140 ℃ and stir; calcine the resulting solid product at 300-450 ℃ for 2-4 h under N2 atmosphere to obtain modified Al2O3 support;

[0015] Step 2, Loading of Active Components: The precursor of the active components is added to deionized water to obtain an impregnation solution; the active components include copper, rare earth metal elements, and transition metal elements other than copper. The modified Al2O3 support obtained in Step 1 is impregnated in the impregnation solution and dried; the resulting solid product is calcined at 300-700℃ for 1-6 hours to obtain a catalyst for the production of chlorine from hydrogen chloride.

[0016] Preferably, in the hydrogen chloride to chlorine catalyst obtained in step two, the mass percentage of copper is 1% to 15%, preferably 3% to 10%, more preferably 4% to 8%; the mass percentage of rare earth metal elements is 0.1% to 10%, preferably 2% to 7%, more preferably 2.5% to 6%; and the mass percentage of transition metal elements is 0.1% to 10%, preferably 1% to 8%, more preferably 2% to 4%.

[0017] Preferably, the transition metal element other than copper is one or more of manganese, vanadium, nickel, cobalt, and zinc, with manganese and vanadium being preferred, and vanadium being even more preferred; the rare earth metal element is one or more of cerium, lanthanum, praseodymium, neodymium, and samarium, with lanthanum, cerium, and neodymium being preferred.

[0018] Preferably, the copper precursor is one or more water-soluble copper salts; the water-soluble copper salts include one or more of copper nitrate, copper chloride, copper sulfate, and copper carbonate, preferably copper nitrate and copper chloride. Generally, when two or more water-soluble copper salts are used, they are combined in any proportion; the precursors of transition metals other than copper are one or more soluble salts of vanadium and manganese, preferably one or more of nitrates, chlorides, or ammonium salts corresponding to vanadium and manganese; the precursors of rare earth metal compounds are nitrates or chlorides of cerium, lanthanum, praseodymium, neodymium, and samarium, preferably nitrates.

[0019] Preferably, the pH value of the impregnation solution in step two is 1 to 5, and more preferably 1 to 3.

[0020] Preferably, in step two, the concentration of the active component precursor in the impregnation solution is 0.1 g / ml to 2 g / ml, and more preferably 0.2 g / ml to 1.2 g / ml.

[0021] Preferably, the drying temperature in step two is 100℃~150℃ and the drying time is 6h~24h, with a preferred temperature of 105℃~120℃ and a drying time of 8h~16h.

[0022] Preferably, the roasting temperature in step two is 450℃~600℃, and the time is 2~5h.

[0023] Secondly, this invention provides a method for producing chlorine from hydrogen chloride, the process of which is as follows: adding the hydrogen chloride-to-chlorine catalyst prepared by the aforementioned method to a fixed-bed reactor; and introducing hydrogen chloride gas and oxygen into the fixed-bed reactor at a reaction temperature of 300℃~500℃ at a molar ratio of (0.5~9):1. The volume hourly space velocity of hydrogen chloride is 500 h⁻¹. -1 ~5000h -1 .

[0024] Preferably, the reaction temperature in the fixed-bed reactor is 360–450 °C; the molar ratio of hydrogen chloride to oxygen is (1–4):1; and the volume hourly space velocity of hydrogen chloride is 1000 h⁻¹. -1 ~3000h -1 .

[0025] The present invention has the following beneficial effects.

[0026] 1. This invention modifies the Al2O3 support using a simple and easy-to-operate method to increase the five-coordinated aluminum (Al) content in the Al2O3 support. p Quantity; five-coordinated aluminum Al p It is an important metal anchoring point, and the five-coordinated aluminum Al on the carrier surface p It can serve as an important anchoring point at the metal-carrier interface, which is beneficial for the electronic interaction between the metal and Al2O3 defects. In subsequent impregnation and calcination, Al... p The stable binding with the active components allows Cu and CeVO4 to be highly dispersed on the surface of the Al2O3 support.

[0027] 2. This invention modifies the Al2O3 support to increase the amount of five-coordinated aluminum (Al) in the Al2O3 support. p The quantity, Al p The metal anchoring effect can enhance the interaction between the support and the active component, reduce the loss of the active component of the catalyst, and thus improve the high-temperature thermal stability, long-term durability and anti-poisoning ability of the catalyst.

[0028] 3. In the reaction process of producing chlorine from hydrogen chloride, HCl molecules are adsorbed onto the oxygen vacancies on the catalyst surface. Cl ions occupy these oxygen vacancies, thus poisoning the catalyst. The CeVO4 solid solution in the catalyst of this invention can reduce catalyst poisoning and enhance catalyst stability. Detailed Implementation

[0029] The present invention will be further illustrated by the following examples, but is by no means limited to the following embodiments.

[0030] The present invention will be illustrated below with specific examples. It should be noted that these embodiments are only for illustrating the present invention.

[0031] This is a further explanation, but it should not be construed as limiting the scope of protection of the present invention, which is not limited in any way. Those skilled in the art can make some non-essential improvements and adjustments based on the above-described invention.

[0032] Example 1

[0033] A method for preparing a hydrogen chloride-to-chlorine catalyst based on a modified alumina support is described below:

[0034] Step 1: Carrier preparation.

[0035] Weigh 10.0 g of Al₂O₃ support and place it in a 250 mL beaker. Add 50 mL of glacial acetic acid. Seal the beaker with a polyethylene film and place it in a 120 ℃ oil bath with stirring for 1 h. After cooling to room temperature, evaporate the solution under vacuum. Then, under a N₂ atmosphere with a heating rate of 2 ℃ / min, raise the temperature to 300 ℃ and hold for 2 h. After cooling to room temperature, the modified support Al₂O₃ is obtained. p The content is 31%.

[0036] Step 2: Loading of active ingredients.

[0037] 4.34 g Cu(NO3)2, 4.93 g Ce(NO3)3·6H2O, and 2.25 g NH4VO3 were dissolved in 15.0 g deionized water to obtain an impregnation solution. The impregnation solution was slowly poured into the carrier prepared above, and the carrier was shaken to ensure uniform impregnation. The mixture was stirred at 60 °C for 2 h, kept at 40 °C for 12 h, dried at 110 °C for 12 h, and calcined at 450 °C for 4 h to obtain a catalyst for the catalytic oxidation of hydrogen chloride to chlorine.

[0038] The performance of the catalyst prepared in this embodiment was tested as follows:

[0039] 2.0 g of catalyst was placed in a quartz reaction tube with an inner diameter of 12 mm and a height of 250 mm. Using HCl / O2 = 1 / 1 as the raw material, the reaction was carried out at an HCl space velocity of 1000 h⁻¹. -1 The reaction to produce chlorine by hydroxylation of hydrogen chloride was carried out at a reaction temperature of 430 ℃ and a reaction pressure of 0.1 MPa (absolute pressure). After 100 h of continuous reaction, the HCl conversion rate was 88.3%. After 500 h of continuous reaction under the same conditions, the HCl conversion rate was 87.1%, and the catalyst activity remained stable. ICP testing of the catalyst after 500 h of reaction showed that the overall catalyst loss was 3.9%.

[0040] The testing process for hydrogen chloride conversion rate in this embodiment is as follows:

[0041] The reactor outlet gas contains chlorine, a small amount of water vapor, oxygen, and unreacted hydrogen chloride. The contents of hydrogen chloride and chlorine in the tail gas were determined using iodometric titration and acid-base titration, respectively, and the hydrogen chloride conversion rate and chlorine space-time yield were calculated accordingly. A saturated KI solution was used as the absorbent to absorb the chlorine and hydrogen chloride in the tail gas.

[0042] Analysis of the amount of chlorine produced: Chlorine in the exhaust gas will displace I in the absorbent liquid. -I2 is generated. Add 2-3 drops of 0.5% starch indicator and titrate with 0.1 mol / L Na2S2O3 standard solution until the solution becomes colorless. The volume of Na2S2O3 standard solution consumed is recorded as VNa2S2O3.

[0043] To analyze the amount of unreacted hydrogen chloride: add 2-3 drops of phenolphthalein indicator and titrate with 0.1 mol / L NaOH standard solution. The endpoint is reached when the solution turns light pink. The volume of NaOH standard solution consumed is recorded as VNaOH.

[0044] The reaction equations are shown in equations (1), (2), and (3):

[0045] Cl2 + 2KI = 2KCl + I2 Equation (1)

[0046] 2NaS2O3 + I2 = Na2S4O6 + 2KI Equation (2)

[0047] NaOH + HCl = NaCl + H2O (Equation 3)

[0048] The conversion rate of HCl was calculated based on the titration analysis results; the conversion rate of HCl The expression is as follows:

[0049]

[0050] Where: VNa2S2O3 is the volume of Na2S2O3 consumed, CNa2S2O3 is the concentration of the Na2S2O3 standard solution, VNaOH is the volume of NaOH consumed, and CNaOH is the concentration of the NaOH standard solution.

[0051] Example 2

[0052] A method for preparing a hydrogen chloride-to-chlorine catalyst based on a modified alumina support is described below:

[0053] Step 1: Carrier preparation.

[0054] Weigh 10.0 g of Al₂O₃ support and place it in a 250 mL beaker. Add 50 mL of glacial acetic acid. Seal the beaker with a polyethylene film and place it in an oil bath at 140 ℃ with stirring for 1 h. After cooling to room temperature, evaporate the solution under vacuum. Then, under a N₂ atmosphere at a heating rate of 2 ℃ / min, raise the temperature to 350 ℃ and hold for 4 h. After cooling to room temperature, the modified support Al₂O₃ is obtained. p The content is 37%.

[0055] Step 2: Loading of active ingredients.

[0056] 4.34 g Cu(NO3)2, 4.93 g Ce(NO3)3·6H2O, and 2.25 g NH4VO3 were dissolved in 15.0 g deionized water to obtain an impregnation solution. The impregnation solution was slowly poured into the carrier prepared above, and the carrier was shaken to ensure uniform impregnation. The mixture was stirred at 60°C for 2 h, kept at 40°C for 12 h, dried at 110°C for 12 h, and calcined at 500°C for 4 h to obtain a catalyst for the catalytic oxidation of hydrogen chloride to chlorine.

[0057] The performance of the catalyst prepared in this embodiment was tested as follows:

[0058] 2.0 g of catalyst was placed in a quartz reaction tube with an inner diameter of 12 mm and a height of 250 mm. Using HCl / O2 = 1 / 1 as the raw material, the reaction was carried out at an HCl volume hourly space velocity of 1000 h⁻¹. -1 The reaction to produce chlorine by hydroxyl chloride was carried out at a reaction temperature of 430 ℃ and a reaction pressure of 0.1 MPa (absolute pressure). After 100 h of continuous reaction, the HCl conversion rate was 88.7%, and after 500 h of continuous reaction under the same conditions, the HCl conversion rate was 87.0%. ICP test of the catalyst after 500 h of reaction showed that the overall catalyst loss was 3.5%.

[0059] Example 3

[0060] A method for preparing a hydrogen chloride-to-chlorine catalyst based on a modified alumina support is described below:

[0061] Step 1: Carrier preparation.

[0062] Weigh 10.0 g of Al₂O₃ support and place it in a 250 mL beaker. Add 50 mL of glacial acetic acid. Seal the beaker with a polyethylene film and place it in a 120 ℃ oil bath with stirring for 1 h. After cooling to room temperature, evaporate the solution under vacuum. Then, under a N₂ atmosphere with a heating rate of 2 ℃ / min, raise the temperature to 400 ℃ and hold for 4 h. After cooling to room temperature, the modified support Al₂O₃ is obtained. p The content is 43%.

[0063] Step 2: Loading of active ingredients.

[0064] 4.34 g Cu(NO3)2, 4.93 g Ce(NO3)3·6H2O, and 2.25 g NH4VO3 were dissolved in 15.0 g deionized water to obtain an impregnation solution. The impregnation solution was slowly poured into the carrier prepared above, and the carrier was shaken to ensure uniform impregnation. The mixture was stirred at 60 °C for 2 h, kept at 40 °C for 12 h, dried at 110 °C for 12 h, and calcined at 550 °C for 4 h to obtain a catalyst for the catalytic oxidation of hydrogen chloride to chlorine.

[0065] The performance of the catalyst prepared in this embodiment was tested as follows:

[0066] 2.0 g of catalyst was placed in a quartz reaction tube with an inner diameter of 12 mm and a height of 250 mm. Using HCl / O2 = 1 / 1 as the raw material, the reaction was carried out at an HCl volume hourly space velocity of 1000 h⁻¹. -1 The reaction to produce chlorine by hydroxyl chloride was carried out at a reaction temperature of 430 ℃ and a reaction pressure of 0.1 MPa (absolute pressure). After 100 h of continuous reaction, the HCl conversion rate was 89.8%, and after 500 h of continuous reaction under the same conditions, the HCl conversion rate was 88.7%. ICP test of the catalyst after 500 h of reaction showed that the overall catalyst loss was 2.2%.

[0067] Example 4

[0068] A method for preparing a hydrogen chloride-to-chlorine catalyst based on a modified alumina support is described below:

[0069] Step 1: Carrier preparation.

[0070] Weigh 10.0 g of Al₂O₃ support and place it in a 250 mL beaker. Add 50 mL of glacial acetic acid. Seal the beaker with a polyethylene film and place it in a 130 ℃ oil bath with stirring for 1 h. After cooling to room temperature, evaporate the solution under vacuum. Then, under a N₂ atmosphere with a heating rate of 2 ℃ / min, raise the temperature to 450 ℃ and hold for 2 h. After cooling to room temperature, the modified support Al₂O₃ is obtained. p The content is 35%.

[0071] Step 2: Loading of active ingredients.

[0072] 4.34 g Cu(NO3)2, 4.93 g Ce(NO3)3·6H2O, and 2.25 g NH4VO3 were dissolved in 15.0 g deionized water to obtain an impregnation solution. The impregnation solution was slowly poured into the carrier prepared above, and the carrier was shaken to ensure uniform impregnation. The mixture was stirred at 60 °C for 2 h, kept at 40 °C for 12 h, dried at 110 °C for 12 h, and calcined at 600 °C for 4 h to obtain a catalyst for the catalytic oxidation of hydrogen chloride to chlorine.

[0073] The performance of the catalyst prepared in this embodiment was tested as follows:

[0074] 2.0 g of catalyst was placed in a quartz reaction tube with an inner diameter of 12 mm and a height of 250 mm. Using HCl / O2 = 1 / 1 as the raw material, the reaction was carried out at an HCl volume hourly space velocity of 1000 h⁻¹. -1 The reaction to produce chlorine by hydroxyl chloride was carried out at a reaction temperature of 430 ℃ and a reaction pressure of 0.1 MPa (absolute pressure). After 100 h of continuous reaction, the HCl conversion rate was 88.1%, and after 500 h of continuous reaction under the same conditions, the HCl conversion rate was 86.7%. ICP test of the catalyst after 500 h of reaction showed that the overall catalyst loss was 2.9%.

[0075] Comparative Example 1

[0076] A method for preparing a catalyst supported on unmodified Al2O3, the process of which is as follows:

[0077] Dissolve 4.34 g Cu(NO3)2, 4.93 g Ce(NO3)3·6H2O, and 2.25 g NH4VO3 in 15.0 g deionized water to obtain an impregnation solution. Slowly pour the impregnation solution into unmodified Al-free... p Commercial Al2O3 (purchased from Zhengzhou Jintai Aluminum Co., Ltd.) carrier was shaken to ensure uniform impregnation, stirred at 60 ℃ for 2 h, kept at 40 ℃ for 12 h, dried at 110 ℃ for 12 h, and calcined at 550 ℃ for 4 h to obtain a catalyst for the catalytic oxidation of hydrogen chloride to chlorine.

[0078] The performance of the catalyst prepared in this comparative example was tested as follows:

[0079] 2.0 g of catalyst was placed in a quartz reaction tube with an inner diameter of 12 mm and a height of 250 mm. Using HCl / O2 = 1 / 1 as the raw material, the reaction was carried out at an HCl volume hourly space velocity of 1000 h⁻¹. -1The reaction to produce chlorine by hydroxylation of hydrogen chloride was carried out at a reaction temperature of 430 ℃ and a reaction pressure of 0.1 MPa (absolute pressure). After 100 h of continuous reaction, the HCl conversion rate was 88.6%. After 500 h of continuous reaction under the same conditions, the HCl conversion rate was 82.4%, and the catalyst activity remained stable. ICP testing of the catalyst after 500 h of reaction showed that the overall catalyst loss was 4.5%.

[0080] Example 5

[0081] A method for preparing a hydrogen chloride-to-chlorine catalyst based on a modified alumina support is described below:

[0082] Step 1: Carrier preparation.

[0083] 10.0 g of Al2O3 support was weighed and placed in a 250 mL beaker. 50 mL of glacial acetic acid was added. The beaker was sealed with polyethylene film and placed in an oil bath at 120 ℃ with stirring for 1 h. After cooling to room temperature, it was dried by vacuum rotary evaporation. Then, under a N2 atmosphere at a heating rate of 2 ℃ / min, the temperature was increased to 400 ℃ and held for 4 h. After cooling to room temperature, the modified Al2O3 support with an Alp content of 43% was obtained.

[0084] Step 2: Loading of active ingredients.

[0085] 4.34 g Cu(NO3)2, 4.93 g Ce(NO3)3·6H2O, and 2.25 g NH4VO3 were dissolved in 15.0 g deionized water to obtain an impregnation solution. An appropriate amount of dilute HNO3 was added to adjust the pH of the impregnation solution to 1.5. The impregnation solution was slowly poured into the prepared support, shaken to ensure uniform impregnation, stirred at 60 ℃ for 2 h, kept at 40 ℃ for 12 h, dried at 110 ℃ for 12 h, and calcined at 550 ℃ for 4 h to obtain a catalyst for the catalytic oxidation of hydrogen chloride to chlorine.

[0086] The performance of the catalyst prepared in this embodiment was tested as follows:

[0087] 2.0 g of catalyst was placed in a quartz reaction tube with an inner diameter of 12 mm and a height of 250 mm. Using HCl / O2 = 1 / 1 as the raw material, the reaction was carried out at an HCl space velocity of 1000 h⁻¹. -1The reaction to produce chlorine by hydroxylation of hydrogen chloride was carried out at a reaction temperature of 430 ℃ and a reaction pressure of 0.1 MPa (absolute pressure). After 100 h of continuous reaction, the HCl conversion rate was 88%. After 500 h of continuous reaction under the same conditions, the HCl conversion rate was 84.1%, and the catalyst activity remained stable. ICP testing of the catalyst after 500 h of reaction showed that the overall catalyst loss was 3.8%.

[0088] Example 6

[0089] A method for preparing a hydrogen chloride-to-chlorine catalyst based on a modified alumina support is described below:

[0090] Step 1: Carrier preparation.

[0091] 10.0 g of Al2O3 support was weighed and placed in a 250 mL beaker. 50 mL of glacial acetic acid was added. The beaker was sealed with polyethylene film and placed in an oil bath at 120 ℃ with stirring for 1 h. After cooling to room temperature, it was dried by vacuum rotary evaporation. Then, under a N2 atmosphere at a heating rate of 2 ℃ / min, the temperature was increased to 400 ℃ and held for 4 h. After cooling to room temperature, the modified Al2O3 support with an Alp content of 43% was obtained.

[0092] Step 2: Loading of active ingredients.

[0093] 4.34 g Cu(NO3)2, 4.93 g Ce(NO3)3·6H2O, and 2.25 g NH4VO3 were dissolved in 15.0 g deionized water to obtain an impregnation solution. An appropriate amount of dilute HNO3 was added to adjust the pH of the impregnation solution to 2.3. The impregnation solution was slowly poured into the prepared support, shaken to ensure uniform impregnation, stirred at 60 ℃ for 2 h, kept at 40 ℃ for 12 h, dried at 110 ℃ for 12 h, and calcined at 550 ℃ for 4 h to obtain a catalyst for the catalytic oxidation of hydrogen chloride to chlorine.

[0094] The performance of the catalyst prepared in this embodiment was tested as follows:

[0095] 2.0 g of catalyst was placed in a quartz reaction tube with an inner diameter of 12 mm and a height of 250 mm. Using HCl / O2 = 1 / 1 as the raw material, the reaction was carried out at an HCl space velocity of 1000 h⁻¹. -1The reaction to produce chlorine by hydroxylation of hydrogen chloride was carried out at a reaction temperature of 430 ℃ and a reaction pressure of 0.1 MPa (absolute pressure). After 100 h of continuous reaction, the HCl conversion rate was 90.2%. After 500 h of continuous reaction under the same conditions, the HCl conversion rate was 89.1%, and the catalyst activity remained stable. ICP testing of the catalyst after 500 h of reaction showed that the overall catalyst loss was 2.0%.

[0096] Example 7

[0097] A method for preparing a hydrogen chloride-to-chlorine catalyst based on a modified alumina support is described below:

[0098] Step 1: Carrier preparation.

[0099] 10.0 g of Al2O3 support was weighed and placed in a 250 mL beaker. 50 mL of glacial acetic acid was added. The beaker was sealed with polyethylene film and placed in an oil bath at 120 ℃ with stirring for 1 h. After cooling to room temperature, it was dried by vacuum rotary evaporation. Then, under a N2 atmosphere at a heating rate of 2 ℃ / min, the temperature was increased to 400 ℃ and held for 4 h. After cooling to room temperature, the modified Al2O3 support with an Alp content of 43% was obtained.

[0100] Step 2: Loading of active ingredients.

[0101] 4.34 g Cu(NO3)2, 4.93 g Ce(NO3)3·6H2O, and 2.25 g NH4VO3 were dissolved in 15.0 g deionized water to obtain an impregnation solution. An appropriate amount of ethanolamine was added to adjust the pH of the impregnation solution to 4.0. The impregnation solution was slowly poured into the prepared support, shaken to ensure uniform impregnation, stirred at 60 ℃ for 2 h, kept at 40 ℃ for 12 h, dried at 110 ℃ for 12 h, and calcined at 550 ℃ for 4 h to obtain a catalyst for the catalytic oxidation of hydrogen chloride to chlorine.

[0102] The performance of the catalyst prepared in this embodiment was tested as follows:

[0103] 2.0 g of catalyst was placed in a quartz reaction tube with an inner diameter of 12 mm and a height of 250 mm. Using HCl / O2 = 1 / 1 as the raw material, the reaction was carried out at an HCl space velocity of 1000 h⁻¹. -1The reaction to produce chlorine by hydroxylation of hydrogen chloride was carried out at a reaction temperature of 430 ℃ and a reaction pressure of 0.1 MPa (absolute pressure). After 100 h of continuous reaction, the HCl conversion rate was 87.3%. After 500 h of continuous reaction under the same conditions, the HCl conversion rate was 83.1%, and the catalyst activity remained stable. ICP testing of the catalyst after 500 h of reaction showed that the overall catalyst loss was 3.6%.

Claims

1. A method for preparing a hydrogen chloride-to-chlorine catalyst based on a modified alumina support, characterized in that: Includes the following steps: Step 1: Al2O3 support modification: Add Al2O3 to glacial acetic acid and seal; place in an oil bath at 120-140 ℃ and stir; calcine the resulting solid product at 300-450 ℃ for 2-4 h under N2 atmosphere to obtain modified Al2O3 support; Step 2, Loading of active components: Add the precursor of the active component to deionized water to obtain an impregnation solution; the active components include copper, rare earth metal elements and transition metal elements other than copper; the precursor of copper is one or more water-soluble copper salts; the precursor of transition metals other than copper is vanadium ammonium salt; the precursor of rare earth metal compounds is cerium nitrate. The modified Al2O3 support obtained in step one was impregnated in an impregnation solution and dried; the resulting solid product was calcined at 300–700 °C for 1–6 h to obtain a hydrogen chloride to chlorine catalyst; in the hydrogen chloride to chlorine catalyst, the mass percentage of copper was 1%–15%; the mass percentage of rare earth metal elements was 0.1%–10%; and the mass percentage of transition metal elements was 0.1%–10%.

2. The method for preparing a hydrogen chloride-to-chlorine catalyst based on a modified alumina support according to claim 1, characterized in that: The pH value of the impregnation solution in step two is 1 to 5.

3. The method for preparing a hydrogen chloride-to-chlorine catalyst based on a modified alumina support according to claim 1, characterized in that: In step two, the concentration of the active component precursor in the impregnation solution is 0.1 g / ml to 2 g / ml.

4. The method for preparing a hydrogen chloride-to-chlorine catalyst based on a modified alumina support according to claim 1, characterized in that: The drying temperature in step two is 105℃~120℃, and the drying time is 8h~16h.

5. The method for preparing a hydrogen chloride-to-chlorine catalyst based on a modified alumina support according to claim 1, characterized in that: In step two, the roasting temperature is 450℃~600℃, and the time is 2~5h.

6. A method for producing chlorine from hydrogen chloride, comprising the following steps: adding the hydrogen chloride catalyst for producing chlorine obtained by the preparation method described in claim 1 to a fixed-bed reactor; introducing hydrogen chloride gas and oxygen into the fixed-bed reactor at a reaction temperature of 300℃~500℃ at a molar ratio of (0.5~9):1; the volume hourly space velocity of hydrogen chloride being 500 h⁻¹. -1 ~5000h -1 .

7. The method for producing chlorine from hydrogen chloride according to claim 6, characterized in that: The reaction temperature in the fixed-bed reactor was 360–450 °C; the molar ratio of hydrogen chloride to oxygen was (1–4):1; and the volume hourly space velocity (VHSV) of hydrogen chloride was 1000 h⁻¹. -1 ~3000h -1 .

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