Catalyst for chlorine production as well as preparation method and application thereof

Abstract

The invention provides a Cu-based catalyst for preparing chlorine through catalytic oxidation of hydrogen chloride and a preparation method and application of the Cu-based catalyst, the catalyst takes aluminum oxide as a carrier, the catalyst contains 2-10 wt% of Cu, 0.0001-0.5 wt% of S and 0.0001-0.5 wt% of P, the Cu content of the unit specific surface area of the catalyst is 1-50 * 10 <-4 > g / m < 2 >, and the conductivity of the catalyst dispersed in water with the same mass is 1-100 mS / cm. Although the Cu loss sign exists in the use process of the catalyst, the Cu content of the unit specific surface area of the catalyst does not decrease along with the extension of the reaction time, so that the activity is maintained. The catalyst provided by the invention overcomes the phenomenon of activity decline caused by Cu loss in the long-time use process, can realize industrial long-period stable operation, and has very high application value.

Description

Technical Field

[0001] The present invention relates to the technical field of preparing chlorine gas by hydrogen chloride oxidation, and particularly relates to a catalyst for chlorine production, a preparation method thereof, and an application thereof. Background Art

[0002] Chlorine gas is a very important basic chemical raw material. In the production processes of many bulk chemicals such as polyurethane intermediates, polyvinyl chloride, organic chlorine intermediates, and epoxy resins, chlorine gas is often used as a raw material, and a large amount of hydrogen chloride is by-produced. The proper treatment of the by-produced hydrogen chloride is directly related to the expansion of the production capacity of the above-mentioned bulk chemicals. The simplest way to treat the by-produced hydrogen chloride is to directly absorb it with an alkali, but this will produce a large amount of waste brine that is difficult to recycle. The catalytic oxidation of hydrogen chloride to chlorine gas can not only treat the by-produced hydrogen chloride on a large scale, but also the generated chlorine gas can continue to be used as a raw material, which is the best solution to achieve nearly 100% chlorine recycling. The key to this solution lies in the development of an efficient catalyst.

[0003] In the reported literature, catalysts obtained with transition metals such as gold, ruthenium, chromium, and copper as active components have good activity for the oxidation of hydrogen chloride to chlorine gas. However, among them, the noble metal gold and ruthenium-based catalysts have high costs and high requirements for the purity of reaction raw materials, and it is difficult to directly use them in industrial devices with complex tail gas components; the chromium-based catalyst is highly toxic and causes great environmental pollution; the copper-based catalyst has received extensive attention due to its activity, cost advantages, and environmental friendliness.

[0004] The copper-based catalysts used for hydrogen chloride oxidation are generally supported catalysts. The active components are highly dispersed on the carrier to maintain their activity and stability. The active component for catalyzing the oxidation of hydrogen chloride is copper chloride. However, copper chloride has a relatively low boiling point. Under the high-temperature working conditions of the reaction, with the extension of the use time, copper chloride will gradually volatilize and be lost, which causes the activity of the catalyst to decline and limits its industrial life.

[0005] To obtain a catalyst with high activity and high stability, researchers have made a lot of efforts. Selecting a suitable carrier to enhance its anchoring effect on copper chloride, selecting suitable alkali metal elements, rare earth metal elements, and other additives to enhance its modification of copper chloride, and inhibiting its volatilization and adhesion are all effective measures to improve the activity and stability of the catalyst.

[0006] US3260678A reports a copper-based catalyst supported on silica gel, which requires the specific surface area of the carrier > 200m 2 / g and the average pore diameter > 6nm. The HCl conversion rate of this catalyst reaches 80% at 350°C, but according to Example 1, the reaction space velocity is very low, which is 40L (HCl) ·kg (cat) -1 ·h -1 .

[0007] CN108097232A reported a catalyst prepared by mixing two different formula powders, which has good comprehensive performance, and the HCl conversion rate at the reaction temperature of 350 - 360 °C is 85%, but the preparation process of this catalyst is relatively complex.

[0008] Based on the characteristics of the copper-based catalyst and the above research background, it is necessary to develop a catalyst with a simple preparation process, high activity and high stability. Summary of the Invention

[0009] The prior art focuses on controlling the Cu loss rate. However, the inventor found that even if there is Cu loss in the catalyst, by controlling the Cu loss rate and the decline rate of the catalyst specific surface area, the Cu content per unit specific surface area of the catalyst does not show a downward trend with the extension of the reaction time. Based on the above findings, the present invention provides a catalyst for chlorine production, its preparation method and application. The catalyst preparation process provided by the present invention is simple, and has the characteristics of high activity and high stability, and has industrial application value.

[0010] The technical solution adopted by the present invention to achieve its purpose is as follows:

[0011] One of the purposes of the present invention is to provide a supported Cu-based catalyst for the oxidation of hydrogen chloride to chlorine, with alumina as the carrier, and the catalyst has the following properties:

[0012] (1) The Cu content of the catalyst is 2 - 10 wt%, preferably 3 - 8 wt%;

[0013] (2) The catalyst contains 0.0001 - 0.5 wt% of S and 0.0001 - 0.5 wt% of P, preferably the P content is 0.0002 - 0.4 wt% (such as 0.001%, 0.01%, 0.1%, etc.), and the S content is 0.0002 - 0.4 wt% (such as 0.001%, 0.01%, 0.1%, etc.);

[0014] (3) The Cu content per unit specific surface area of the catalyst is 1 - 50*10 -4 g / m 2 , preferably the Cu content per unit specific surface area of the catalyst is 2 - 40*10 -4 g / m 2 (such as 5*10 -4 , 10*10 -4 , 20*10 -4 , etc.);

[0015] (4) The conductivity of the catalyst dispersed in an equal mass of water is between 1 - 100 mS / cm, preferably between 2 - 80 mS / cm.

[0016] The catalyst of the present invention further contains 2-20 wt% of rare earth elements, preferably 3-15 wt% of rare earth elements, 2-10 wt% of alkali metal elements, preferably 2-8 wt% of alkali metal elements, and 0-10 wt% of other metal elements, preferably 0.01-5 wt% of other metal elements. The alkali metal element is selected from one or two of potassium and sodium; the rare earth element is selected from one or more of cerium, lanthanum, praseodymium, neodymium, and samarium; the other metal element is selected from one or more of magnesium, calcium, barium, manganese, iron, nickel, cobalt, zinc, ruthenium, or titanium elements.

[0017] The second object of the present invention is to provide a preparation method of a copper hydroxide-based catalyst for chlorine production by hydrogen chloride oxidation, comprising the following steps:

[0018] (1) Dissolve the precursors of Cu and other elements to obtain an active component solution, and the active component solution contains chlorine element and does not contain P and S elements;

[0019] (2) Disperse the precursor containing carrier alumina in water to obtain a carrier slurry;

[0020] (3) Under stirring, mix the active component solution and the carrier slurry to obtain a paste, and the viscosity of the paste > 6000 mPa·S, preferably > 7000 mPa·S, and there is no upper limit;

[0021] (4) Add an aqueous solution containing P and S elements to the paste and stir to obtain a slurry, so that the viscosity of the slurry is 1000-6000 mPa·S, preferably 2000-5000 mPa·S;

[0022] (5) Remove the moisture in the slurry to obtain a dry mixture;

[0023] (6) Calcinate the dry mixture to obtain the catalyst, and the calcination temperature is 400-700 °C, preferably 450-650 °C.

[0024] In the preparation method of the catalyst of the present invention, the precursor can be selected from one or more of its water-soluble salts, including but not limited to its nitrates, acetates, chlorides, and specific examples can include copper nitrate, potassium nitrate, potassium chloride, copper chloride, copper acetate, lanthanum nitrate, cerium nitrate, cerium chloride, lanthanum chloride, praseodymium nitrate, neodymium nitrate, magnesium nitrate, iron chloride, manganese nitrate, etc., and there is no special limitation.

[0025] The precursor containing carrier alumina of the present invention can be one or more of alumina or alumina hydrates, such as alumina powder, pseudo-boehmite, aluminum sol, boehmite, aluminum hydroxide, and other crystalline alumina or its precursors.

[0026] In the present invention, the P or S element is added in the form of its acid, such as phosphoric acid, phosphorous acid, metaphosphoric acid, hypophosphorous acid, sulfuric acid, sulfurous acid, etc.

[0027] In the catalyst preparation method of the present invention, an acidic liquid can be selectively added to step 1 and / or 2 and / or 3, and the amount used is such that the pH of the finally obtained paste is ≤ 5, preferably pH ≤ 4. The acidic liquid is selected from one or both of nitric acid and hydrochloric acid.

[0028] The third object of the present invention is to provide a method for preparing chlorine by the oxidation of hydrogen chloride. In the presence of a catalyst, hydrogen chloride is oxidized to produce chlorine, and the catalyst is the catalyst described above.

[0029] The raw material gas of the present invention contains hydrogen chloride and oxygen. According to needs, it may further contain nitrogen, CO, CO2, chlorinated hydrocarbons, fluorinated hydrocarbons, etc.

[0030] In the method for preparing chlorine by the oxidation of hydrogen chloride of the present invention, the oxidation reaction can be carried out in a fixed bed or in a fluidized bed reactor. During the oxidation reaction process, the highest temperature in the reactor is controlled to be 300 - 500 °C, preferably 320 - 450 °C.

[0031] In a specific preferred embodiment of the method for preparing chlorine by the oxidation of hydrogen chloride of the present invention, the process conditions preferably include: the mass space velocity of hydrogen chloride is 0.05 - 1.5 h -1 , the molar ratio of hydrogen chloride to oxygen is 1 - 4, and the reaction pressure is from atmospheric pressure to 5 atmospheres (absolute pressure).

[0032] In the method of the present invention, the Cu content per unit specific surface area of the catalyst does not show a downward trend with the prolongation of the reaction time. On the contrary, with the prolongation of the reaction time, the Cu content per unit specific surface area of the catalyst shows a certain upward trend. For example, in a specific preferred embodiment of the present invention, the initial value of the Cu content per unit specific surface area of the catalyst is 2.88×10 -4 g / m 2 , after reacting for 5000 h, the Cu content per unit specific surface area of the catalyst is 3.09×10 -4 g / m 2 , after reacting for 10000 h, the Cu content per unit specific surface area of the catalyst is 3.46×10 -4 g / m 2 .

[0033] The technical solution provided by the present invention has the following beneficial effects:

[0034] The catalyst provided by the present invention uses alumina as a carrier and contains a certain amount of S and P elements. Combining with the special preparation method of the present invention, the decline rate of Cu loss in the catalyst during the reaction process is less than the decline rate of the specific surface area of the catalyst over time. (Even if Cu loss occurs), the Cu content per unit specific surface area of the catalyst does not show a downward trend over the reaction time, and even has a certain increase, which makes the catalyst have particularly high activity stability. The reason for this phenomenon of the present catalyst is that under the preparation method of the present invention, the combination of S and P elements under the reaction conditions has a certain effect on the Cu element and the alumina carrier, so that on the one hand, the Cu content per unit specific surface area of the catalyst increases, and on the other hand, the catalyst does not have the problem of caking, so the activity of the catalyst can still be maintained. The present catalyst has industrial application value. Detailed implementation mode

[0035] To better understand the technical solution of the present invention, the content of the present invention will be further elaborated below in conjunction with embodiments, but the content of the present invention is not limited to the following embodiments.

[0036] The test methods used in the following examples or comparative examples are introduced below:

[0037] 1. Test method for hydrogen chloride conversion rate:

[0038] In each example, during the catalyst reaction performance test, samples were taken 3 times every 24 h for analysis, and the average conversion rate of the entire operation process was used as the conversion rate of the catalyst.

[0039] The test method for the hydrogen chloride conversion rate of any single time is as follows:

[0040] (1) Detection principle

[0041] Cl2 + 2KI = 2KCl + I2

[0042] I2 + 2Na2S2O3 = 2NaI + Na2S4O6

[0043] HCl + NaOH = NaCl + H2O

[0044] (2) Preparation and calibration of 0.1 mol / L Na2S2O3 solution

[0045] Weigh about 6.2 g of Na2S2O3·5H2O, dissolve it in an appropriate amount of freshly boiled and cooled distilled water (removing O2 and CO2 in the water), add 0.05 - 0.1 g of Na2CO3 (to inhibit the growth of microorganisms), make up 250 mL of solution, and store it in a brown bottle in the dark; perform calibration after storing for 2 weeks.

[0046] Accurately weigh 0.15 g of K2Cr2O7 (dried at 110 °C for 2 h) into an iodine flask, add 20 mL of water to dissolve it, then add 2 g of KI and 10 mL of 1 wt% H2SO4, shake well and let stand for 5 minutes. Then add 50 mL of water for dilution, titrate with the Na2S2O3 solution until the solution turns light yellowish green, add 2 mL of starch indicator, and continue titrating with the Na2S2O3 solution until the solution changes from blue to light green (the end point shows a very light green color of Cr 3+ ). Repeat the standardization 3 times and take the average value.

[0047] (3) Analytical detection process

[0048] a) Sampling: Replace the 250 mL sampling bottle with the gas to be measured for 3 min (the gas enters from the bottom and exits from the top) to ensure that there are no impurities in the sampling bottle. React the sample gas in the sampling bottle fully with the aqueous solution of KI with a mass concentration of 15 wt%. The Cl2 in the sample gas reacts with KI to generate I2 (dissolved in the absorption solution in the form of I3 - . If there is an I2 precipitate, it will easily lead to poor result accuracy and a new sample needs to be taken), and HCl is absorbed to form an aqueous hydrochloric acid solution. Then carry out the titration.

[0049] b) Titration of I2 (I3 - ) in the absorption solution: Take out 25.00 mL of the absorption solution into a 250 mL conical flask, add 50 mL of distilled water for dilution, titrate with the prepared and standardized Na2S2O3 solution until it turns light yellow, add 2 mL of starch solution, and continue titrating until the blue color just disappears, which is the end point. Record the volume of the Na2S2O3 solution consumed in the titration, and the content of I2 (I3 - ) in the absorption solution can be calculated, and then the amount of Cl2 in the sample gas to be measured can be calculated.

[0050] c) Titration of hydrochloric acid in the absorption solution: Add 2 - 3 drops of phenolphthalein reagent to the sample after the titration in step b). The colorless liquid turns red and the red color does not change within half a minute (if it does not change from colorless to red, on the premise that the experimental process is correct, it means there is no hydrochloric acid in the absorption solution). Then titrate with the prepared and standardized NaOH standard solution until it becomes colorless, which is the titration end point. Record the volume of the NaOH standard solution consumed in the titration, and the content of H + in the absorption solution can be calculated, and then the amount of HCl in the sample gas to be measured can be calculated.

[0051] (4) Calculate the conversion rate Conv of hydrogen chloride in the sample:

[0052]

[0053] Among them:

[0054] a represents the concentration of the Na2S2O3 solution, mol / L;

[0055] b represents the volume of the Na2S2O3 solution consumed in the titration, mL;

[0056] c represents the concentration of the NaOH standard solution, mol / L;

[0057] d represents the volume of the NaOH standard solution consumed in the titration, mL.

[0058] 2. Method for measuring the viscosity of the catalyst slurry

[0059] It is measured using a Shanghai Changji NDJ-1B rotational viscometer. When measuring, rotor No. 3 is selected and the rotation speed is 60 revolutions per minute.

[0060] 3. Method for measuring the specific surface area and pore structure information of the catalyst

[0061] The BET specific surface area, BJH desorption pore volume and pore diameter of the catalyst are obtained by N2 physical adsorption method, and the test instrument model is Micrometics ASAP 2460.

[0062] 4. Measurement of the conductivity of the catalyst dispersed in an equal mass of water

[0063] Take 100 g of the catalyst and disperse it in 100 g of deionized water, stir for 1 h, and measure the conductivity of the supernatant after standing. The brand model of the conductivity meter is Leici DDSJ-318T conductivity meter.

[0064] 5. Catalyst raw materials

[0065] The metal salt raw materials used in the examples or comparative examples of the present invention are all purchased from Xilong Chemical Co., Ltd. The alumina powder is purchased from Zibo Chaoke Alumina Materials Co., Ltd. Pseudoboehmite (calcination loss 30%) and aluminum sol are purchased from Zibo Jinqi Chemical Technology Co., Ltd. The silica sol is purchased from Shandong Best Materials Co., Ltd. Other raw materials are also commercially available raw materials without special instructions.

[0066] Example 1

[0067] (1) Catalyst preparation

[0068] Weigh 200 g of alumina powder and disperse it in 467 g of water. Under stirring, add 2230 g of an aluminum sol with a solid content of 30 wt%, and after stirring evenly, add 9.7 g of nitric acid (68%) to obtain a wet mixed carrier slurry.

[0069] Weigh 100 g of copper chloride (CuCl₂·2H₂O), 150 g of neodymium nitrate (Nd(NO₃)₃·6H₂O), 45 g of potassium chloride (KCl), 10 g of magnesium chloride (MgCl₂·6H₂O), and 10 g of an aqueous solution of manganese nitrate (Mn(NO₃)₂) with a concentration of 50 wt%. Dissolve them in 500 g of water to obtain a mixed solution. During the stirring process, add the mixed carrier slurry prepared above, and continue stirring for 1 h to obtain a paste with a viscosity of 7100 mPa·s. The pH of the paste is 3.6.

[0070] Add an aqueous solution of 0.11 g of sulfuric acid (98%) and 0.08 g of phosphoric acid (85%) dissolved in 300 g of water to the paste, and stir to obtain a slurry with a viscosity of 4700 mPa·S; after centrifugal spray drying, obtain a dry mixture; then calcine at 600 °C for 5 h to obtain a catalyst product.

[0071] After analysis, the Cu content on the catalyst is 3.51 wt%, the P content is 0.0020 wt%, the S content is 0.0033 wt%, the specific surface area is 122 m 2 / g, and the Cu content per unit specific surface area is 2.88×10 -4 g / m 2 , and the conductivity of the catalyst dispersed in an equal mass of water is 12 mS / cm.

[0072] (2) Catalyst performance test:

[0073] Weigh 1000 g of the catalyst and place it in a fluidized bed reactor with an inner diameter of 30 mm and a height of 700 mm. Control the ratio of hydrogen chloride to oxygen = 2 / 1, and carry out the reaction of hydrogen chloride oxidation to chlorine at a HCl mass space velocity of 0.42 h -1 , a reaction temperature of 390 - 400 °C, and a reaction pressure of 0.3 MPa (absolute pressure). After continuous reaction for 100 h, the HCl conversion rate is 82.8%. Under these conditions, after continuous reaction for 5000 h, the HCl conversion rate is 83.2%, and after continuous reaction for 10000 h, the HCl conversion rate is 83.7%.

[0074] Disassemble the catalyst and conduct ICP (Inductively Coupled Plasma Spectrometer) and BET tests. After continuous reaction for 5000 h, the Cu content on the catalyst is 3.31 wt%, the specific surface area is 107 m 2 / g, and the Cu content per unit specific surface area is 3.09×10 - 4 g / m 2 , after continuous reaction for 10000 h, the Cu content on the catalyst is 3.22 wt%, the specific surface area is 93 m 2 / g, and the Cu content per unit specific surface area is 3.46×10 -4g / m 2 。

[0075] It can be seen that as the reaction time prolongs, the Cu content on the unit specific surface area of the catalyst gradually increases, and the catalyst performance is stable.

[0076] Comparative Example 1

[0077] (1) Catalyst preparation

[0078] Weigh 200 g of alumina powder, disperse it in 467 g of water, add 2230 g of aluminum sol with a solid content of 30 wt% under stirring, and then add 9.7 g of nitric acid (68%) after stirring evenly to obtain a wet mixed carrier slurry.

[0079] Weigh 100 g of copper chloride, 150 g of neodymium nitrate, 45 g of potassium chloride, 10 g of magnesium chloride, and 10 g of an aqueous solution of manganese nitrate with a concentration of 50 wt%, dissolve them in 500 g of water to obtain a mixed solution. During the stirring process, add the mixed carrier slurry prepared above, continue to stir for 1 h to obtain a paste with a viscosity of 7100 mPa·s, and the pH of the paste is 3.6; after centrifugal spray drying, a dry mixture is obtained; then it is calcined at 600 °C for 5 h to obtain the catalyst product.

[0080] After analysis, the Cu content on this catalyst is 3.51 wt%, the specific surface area is 131 m 2 / g, and the Cu content on the unit specific surface area is 2.68×10 -4 g / m 2 , and the conductivity of the catalyst dispersed in the same mass of water is 11 mS / cm.

[0081] (2) Catalyst performance test:

[0082] Weigh 1000 g of the catalyst, put it into a fluidized bed reactor with an inner diameter of 30 mm and a height of 700 mm, control HCl / O₂ = 2 / 1, and carry out the reaction of hydrogen chloride oxidation to chlorine under the conditions of an HCl mass space velocity of 0.42 h -1 , a reaction temperature of 390 - 400 °C, and a reaction pressure of 0.3 MPa (absolute pressure). After continuous reaction for 100 h, the HCl conversion rate is 83.5%. After continuous reaction for 5000 h under this condition, the HCl conversion rate is 81.9%. After continuous reaction for 10000 h, the HCl conversion rate is 79.6%.

[0083] Disassemble the catalyst and conduct ICP (Inductively Coupled Plasma Spectrometer) and BET tests. After continuous reaction for 5000 h, the Cu content on the catalyst is 3.11 wt%, the specific surface area is 125 m 2 / g, and the Cu content on the unit specific surface area is 2.49×10 - 4g / m 2 After continuous reaction for 10,000 h, the Cu content on the catalyst is 2.88 wt%, the specific surface area is 118 m 2 / g, and the Cu content per unit specific surface area is 2.44×10 -4 g / m 2 .

[0084] It can be seen that as the reaction time prolongs, the Cu content per unit specific surface area of the catalyst gradually decreases, and the catalyst performance decreases significantly.

[0085] Comparing Example 1 and Comparative Example 1, the catalyst prepared by the preparation method of the present invention has better activity stability.

[0086] Comparative Example 2

[0087] (1) Catalyst preparation

[0088] Weigh 200 g of alumina powder and disperse it in 467 g of water. Add 2230 g of aluminum sol with a solid content of 30 wt% under stirring. After stirring evenly, add 9.7 g of nitric acid (68%) to obtain a wet mixed carrier slurry.

[0089] Weigh 140.9 g of copper nitrate (Cu(NO3)2·3H2O), 150 g of neodymium nitrate, 45 g of potassium nitrate (KNO3), 19.4 g of magnesium nitrate (Mg(NO3)2·6H2O), and 10 g of 50 wt% manganese nitrate aqueous solution and dissolve them in 500 g of water to obtain a mixed solution. Add the mixed carrier slurry prepared above during stirring, and continue stirring for 1 h to obtain a paste with a viscosity of 900 mPa·s. The pH of the paste is 4.6; after centrifugal spray drying, a dry mixture is obtained; then it is calcined at 600 °C for 5 h to obtain a catalyst product.

[0090] After analysis, the Cu content on this catalyst is 3.62 wt%, the specific surface area is 136 m 2 / g, and the Cu content per unit specific surface area is 2.66×10 -4 g / m 2 , and the conductivity of the catalyst dispersed in the same mass of water is 0.5 mS / cm.

[0091] (2) Catalyst performance test:

[0092] Weigh 1000 g of the catalyst and put it into a fluidized bed reactor with an inner diameter of 30 mm and a height of 700 mm. Control hydrogen chloride / oxygen = 2 / 1, and at a HCl mass space velocity of 0.42 h -1, the reaction of hydrogen chloride oxidation to chlorine is carried out under the conditions of a reaction temperature of 390 - 400 °C and a reaction pressure of 0.3 MPa (absolute pressure). After continuous reaction for 100 h, the HCl conversion rate is 81.4%. Under these conditions, after continuous reaction for 5000 h, the HCl conversion rate is 80.2%, and after continuous reaction for 10000 h, the HCl conversion rate is 78.5%.

[0093] The catalyst was disassembled and subjected to ICP (Inductively Coupled Plasma Spectrometer) and BET tests. After continuous reaction for 5000 h, the Cu content on the catalyst was 3.21 wt%, the specific surface area was 127 m 2 / g, and the Cu content per unit specific surface area was 2.53×10 - 4 g / m 2 , after continuous reaction for 10000 h, the Cu content on the catalyst was 2.78 wt%, the specific surface area was 122 m 2 / g, and the Cu content per unit specific surface area was 2.28×10 -4 g / m 2 .

[0094] It can be seen that with the prolongation of the reaction time, the Cu content per unit specific surface area of the catalyst gradually decreases, and the catalyst performance decreases significantly.

[0095] Comparing Example 1 and Comparative Example 2, the catalyst prepared by the preparation method of the present invention has better activity stability.

[0096] Example 2

[0097] (1) Catalyst preparation

[0098] 285 g of pseudo-boehmite and 669 g of alumina powder were weighed and dispersed in 1230 g of water. After stirring evenly, a wet mixed carrier slurry was obtained.

[0099] 100 g of copper chloride, 150 g of neodymium nitrate, 70 g of potassium chloride, 10 g of magnesium chloride, 10 g of a 50 wt% manganese nitrate aqueous solution, and 2.6 g of hydrochloric acid (38%) were dissolved in 500 g of water to obtain a mixed solution. During stirring, the above-prepared mixed carrier slurry was added, and stirring was continued for 1 h to obtain a paste with a viscosity of 8200 mPa·s and a pH of 3.8 for the paste; 0.88 g of sulfuric acid (98%) and 0.21 g of phosphoric acid (85%) were dissolved in 600 g of water and added to the paste. After stirring, a slurry with a viscosity of 2370 mPa·s was obtained; after centrifugal spray drying, a dry mixture was obtained; then it was calcined at 600 °C for 5 h to obtain the catalyst product.

[0100] After analysis, the Cu content in the catalyst is 3.43 wt%, the P content is 0.0052 wt%, the S content is 0.0261 wt%, and the specific surface area is 147 m 2 / g. The Cu content per unit specific surface area is 2.33×10 -4 g / m 2 . The conductivity of the catalyst dispersed in an equal mass of water is 25 mS / cm.

[0101] (2) Catalyst performance test:

[0102] Weigh 1000 g of the catalyst and place it in a fluidized bed reactor with an inner diameter of 30 mm and a height of 700 mm. Control the ratio of hydrogen chloride to oxygen at 2 / 1. Under the conditions of an HCl mass space velocity of 0.42 h -1 , a reaction temperature of 390 - 400 °C, and a reaction pressure of 0.3 MPa (absolute pressure), carry out the reaction of hydrogen chloride oxidation to chlorine. After continuous reaction for 100 h, the HCl conversion rate is 83.2%. Under these conditions, after continuous reaction for 5000 h, the HCl conversion rate is 82.8%, and after continuous reaction for 10000 h, the HCl conversion rate is 83.0%.

[0103] Disassemble the catalyst and conduct ICP (inductively coupled plasma spectrometer) and BET tests. After continuous reaction for 5000 h, the Cu content in the catalyst is 3.36 wt%, and the specific surface area is 119 m 2 / g. The Cu content per unit specific surface area is 2.82×10 - 4 g / m 2 . After continuous reaction for 10000 h, the Cu content in the catalyst is 3.28 wt%, and the specific surface area is 104 m 2 / g. The Cu content per unit specific surface area is 3.15×10 -4 g / m 2 .

[0104] It can be seen that as the reaction time prolongs, the Cu content per unit specific surface area of the catalyst gradually increases, and the catalyst performance is stable.

[0105] Comparative Example 3

[0106] (1) Catalyst preparation

[0107] Weigh 285 g of pseudo-boehmite and 669 g of alumina powder, disperse them in 1230 g of water, and stir evenly to obtain a wet mixed carrier slurry.

[0108] Weigh 100 g of copper chloride, 150 g of neodymium nitrate, 70 g of potassium chloride, 10 g of magnesium chloride, 10 g of an aqueous solution of manganese nitrate with a concentration of 50 wt%, and 2.6 g of hydrochloric acid (38%). Dissolve them in 500 g of water to obtain a mixed solution. During stirring, add the mixed carrier slurry prepared above, and continue stirring for 1 h to obtain a paste with a viscosity of 8200 mPa·s and a pH of 3.8 for the paste. Add a solution of 0.21 g of phosphoric acid (85%) dissolved in 600 g of water to the paste, and stir to obtain a slurry with a viscosity of 2190 mPa·s. After centrifugal spray drying, a dry mixture is obtained; then calcine it at 600 °C for 5 h to obtain the catalyst product.

[0109] After analysis, the Cu content on the catalyst is 3.43 wt%, the P content is 0.0052 wt%, the specific surface area is 148 m 2 / g, and the Cu content per unit specific surface area is 2.31×10 -4 g / m 2 . The conductivity of the catalyst dispersed in an equal mass of water is 29 mS / cm.

[0110] (2) Catalyst performance test:

[0111] Weigh 1000 g of the catalyst and place it in a fluidized bed reactor with an inner diameter of 30 mm and a height of 700 mm. Control the ratio of hydrogen chloride to oxygen to be 2 / 1, and carry out the reaction of hydrogen chloride oxidation to chlorine under the conditions of an HCl mass space velocity of 0.42 h -1 , a reaction temperature of 390 - 400 °C, and a reaction pressure of 0.3 MPa (absolute pressure). After continuous reaction for 100 h, the HCl conversion rate is 83.5%. Under these conditions, after continuous reaction for 5000 h, the HCl conversion rate is 82.1%, and after continuous reaction for 10000 h, the HCl conversion rate is 79.6%.

[0112] Disassemble the catalyst and conduct ICP (Inductively Coupled Plasma Spectrometer) and BET tests. After continuous reaction for 5000 h, the Cu content on the catalyst is 3.01 wt%, the specific surface area is 138 m 2 / g, and the Cu content per unit specific surface area is 2.22×10 - 4 g / m 2 . After continuous reaction for 10000 h, the Cu content on the catalyst is 2.78 wt%, the specific surface area is 129 m 2 / g, and the Cu content per unit specific surface area is 2.16×10 -4 g / m 2 .

[0113] It can be seen that as the reaction time prolongs, the Cu content per unit specific surface area of the catalyst gradually decreases, and the catalyst performance decreases significantly.

[0114] Example 3

[0115] (1) Catalyst preparation

[0116] Weigh 1240 g of pseudoboehmite and disperse it in 1275 g of water. After stirring evenly, a wet mixed carrier slurry is obtained.

[0117] Weigh 117 g of copper chloride, 34 g of copper nitrate, 139 g of cerium chloride (CeCl3·7H2O), 62 g of potassium chloride, and 5 g of magnesium chloride, dissolve them in 700 g of water to obtain a mixed solution. During stirring, add the above-prepared mixed carrier slurry. After stirring for 0.5 h, add 4.7 g of hydrochloric acid (38%), and continue to stir for 0.5 h to obtain a paste with a viscosity of 9700 mPa·s, and the pH of the paste is 3.9;

[0118] Add a solution of 0.33 g of sulfuric acid (98%) and 4.6 g of phosphoric acid (85%) dissolved in 400 g of water to the paste, and stir to obtain a slurry with a viscosity of 5910 mPa·s; after centrifugal spray drying, a dry mixture is obtained; then calcine it at 600 °C for 5 h to obtain the catalyst product.

[0119] After analysis, the Cu content on this catalyst is 4.62 wt%, the P content is 0.108 wt%, the S content is 0.0093 wt%, the specific surface area is 151 m 2 / g, and the Cu content per unit specific surface area is 3.06*10 -4 g / m 2 , and the conductivity of the catalyst dispersed in an equal mass of water is 86 mS / cm.

[0120] (2) Catalyst performance test:

[0121] Weigh 1000 g of the catalyst and put it into a fluidized bed reactor with an inner diameter of 30 mm and a height of 700 mm. Control hydrogen chloride / oxygen = 2 / 1, and carry out the reaction of hydrogen chloride oxidation to chlorine under the conditions of an HCl mass space velocity of 0.42 h -1 , a reaction temperature of 390 - 400 °C, and a reaction pressure of 0.3 MPa (absolute pressure). After continuous reaction for 100 h, the HCl conversion rate is 84.6%. After continuous reaction for 5000 h under this condition, the HCl conversion rate is 84.1%. After continuous reaction for 10000 h, the HCl conversion rate is 83.6%.

[0122] Disassemble the catalyst and conduct ICP (inductively coupled plasma spectrometer) and BET tests on it. After continuous reaction for 5000 h, the Cu content on the catalyst is 4.29 wt%, the specific surface area is 123 m 2 / g, and the Cu content per unit specific surface area is 3.49*10- 4 g / m 2 After continuous reaction for 10,000 h, the Cu content on the catalyst is 4.12 wt%, the specific surface area is 109 m 2 / g, and the Cu content per unit specific surface area is 3.78×10 -4 g / m 2 .

[0123] It can be seen that as the reaction time prolongs, the Cu content per unit specific surface area of the catalyst gradually increases, and the catalyst performance is stable.

[0124] Comparative Example 4

[0125] (1) Catalyst preparation

[0126] Weigh 1240 g of pseudo-boehmite and disperse it in 1275 g of water. After stirring evenly, a wet mixed carrier slurry is obtained.

[0127] Weigh 167 g of copper chloride, 139 g of cerium chloride, 62 g of potassium chloride, and 5 g of magnesium chloride, dissolve them in 1000 g of water to obtain a mixed solution. During stirring, add the mixed carrier slurry prepared above. After stirring for 0.5 h, add 1.6 g of hydrochloric acid (38%), and continue to stir for 0.5 h to obtain a paste with a viscosity of 3100 mPa·s and a pH of 4.3 for the paste; add a solution of 51 g of sulfuric acid (98%) and 63 g of phosphoric acid (85%) dissolved in 400 g of water to the paste, and stir to obtain a slurry with a viscosity of 8210 mPa·s; after centrifugal spray drying, a dry mixture is obtained; then calcine it at 600 °C for 5 h to obtain a catalyst product.

[0128] After analysis, the Cu content on this catalyst is 5.01 wt%, the P content is 1.37 wt%, the S content is 1.32 wt%, the specific surface area is 108 m 2 / g, and the Cu content per unit specific surface area is 4.64×10 -4 g / m 2 , and the conductivity of the catalyst dispersed in the same mass of water is 103 mS / cm.

[0129] (2) Catalyst performance test:

[0130] Weigh 1000 g of the catalyst and put it into a fluidized bed reactor with an inner diameter of 30 mm and a height of 700 mm. Control hydrogen chloride / oxygen = 2 / 1, and at an HCl mass space velocity of 0.42 h -1, the reaction of hydrogen chloride oxidation to chlorine is carried out under the conditions of a reaction temperature of 390 - 400 °C and a reaction pressure of 0.3 MPa (absolute pressure). After continuous reaction for 100 h, the HCl conversion rate is 72.5%. Under these conditions, after continuous reaction for 5000 h, the HCl conversion rate is 71.3%, and after continuous reaction for 10000 h, the HCl conversion rate is 69.7%.

[0131] The catalyst is disassembled and subjected to ICP (Inductively Coupled Plasma Spectrometer) and BET tests. After continuous reaction for 5000 h, the Cu content on the catalyst is 4.72 wt%, the specific surface area is 102 m 2 / g, and the Cu content per unit specific surface area is 4.63×10 - 4 g / m 2 , after continuous reaction for 10000 h, the Cu content on the catalyst is 4.46 wt%, the specific surface area is 98 m 2 / g, and the Cu content per unit specific surface area is 4.55×10 -4 g / m 2 .

[0132] It can be seen that although the Cu content per unit specific surface area of the catalyst is basically stable and the performance degradation is less with the extension of the reaction time, the overall activity is relatively low.

[0133] Example 4

[0134] (1) Catalyst preparation

[0135] Weigh 600 g of pseudoboehmite, 208 g of alumina powder, and 700 g of aluminum sol with a solid content of 30 wt% dispersed in 1000 g of water. After stirring evenly, a wet mixed carrier slurry is obtained.

[0136] Weigh 166 g of copper chloride, 134 g of copper nitrate, 97 g of neodymium nitrate, 127 g of potassium chloride, 139 g of cerium nitrate (Ce(NO3)3·6H2O), and 170 g of lanthanum nitrate (La(NO3)3·6H2O) and dissolve them in 1100 g of water to obtain a mixed solution. During stirring, add the above-prepared mixed carrier slurry. After stirring for 0.5 h, add 11.2 g of hydrochloric acid (38%), and continue stirring for 0.5 h to obtain a paste with a viscosity of 7840 mPa·s and a pH of 3.3.

[0137] Add a solution of 1.37 g of sulfuric acid (98%) and 3.42 g of phosphoric acid (85%) dissolved in 600 g of water to the paste, stir to obtain a slurry with a viscosity of 4980 mPa·s; after centrifugal spray drying, a dry mixture is obtained; then calcine it at 600 °C for 5 h to obtain the catalyst product.

[0138] After analysis, the Cu content in the catalyst is 7.46 wt%, the P content is 0.0705 wt%, the S content is 0.0337 wt%, and the specific surface area is 92 m 2 / g. The Cu content per unit specific surface area is 8.11*10 -4 g / m 2 . The conductivity of the catalyst dispersed in an equal mass of water is 67 mS / cm.

[0139] (2) Catalyst performance test:

[0140] Weigh 600 g of the catalyst and place it in a fluidized bed reactor with an inner diameter of 30 mm and a height of 700 mm. Control the ratio of hydrogen chloride / oxygen = 1.5 / 1. Under the conditions of an HCl mass space velocity of 0.53 h -1 , a reaction temperature of 400 - 4010 °C, and a reaction pressure of 0.3 MPa (absolute pressure), carry out the reaction of hydrogen chloride oxidation to chlorine. After continuous reaction for 100 h, the HCl conversion rate is 85.8%. After continuous reaction for 5000 h under these conditions, the HCl conversion rate is 86.1%. After continuous reaction for 10000 h, the HCl conversion rate is 85.4%.

[0141] Disassemble the catalyst and conduct ICP (Inductively Coupled Plasma Spectrometer) and BET tests. After continuous reaction for 5000 h, the Cu content in the catalyst is 7.22 wt%, and the specific surface area is 76 m 2 / g. The Cu content per unit specific surface area is 9.50*10 - 4 g / m 2 . After continuous reaction for 10000 h, the Cu content in the catalyst is 7.05 wt%, and the specific surface area is 55 m 2 / g. The Cu content per unit specific surface area is 12.8*10 -4 g / m 2 .

[0142] It can be seen that as the reaction time prolongs, the Cu content per unit specific surface area of the catalyst gradually increases, and the catalyst performance is stable.

Claims

1. A supported Cu-based catalyst for the oxidation of hydrogen chloride to chlorine, characterized in that: (1) The catalyst uses alumina as the carrier and the Cu content is 2-10 wt%; (2) The catalyst contains 0.0001-0.5 wt% of S and 0.0001-0.5 wt% of P; (3) The Cu content per unit specific surface area of the catalyst is 1 to 50×10 -4 g / m 2 ; (4) The conductivity of the catalyst dispersed in an equal mass of water is 1-100 mS / cm.

2. The catalyst according to claim 1, wherein The Cu content of the catalyst is 3-8 wt%, the P content is 0.0002-0.4 wt%, the S content is 0.0002-0.4 wt%, and the Cu content per unit specific surface area of the catalyst is 2-40*10 -4 g / m 2 .

3. The catalyst according to claim 1 or 2, characterized in that, The catalyst also contains 2-20 wt% of rare earth elements, preferably 3-15 wt% of rare earth elements, 2-10 wt% of alkali metal elements, preferably 2-8 wt% of alkali metal elements, and 0-10 wt% of other metal elements, preferably 0.01-5 wt% of other metal elements; Preferably, the alkali metal element is selected from one or two of potassium and sodium; the rare earth element is selected from one or more of cerium, lanthanum, praseodymium, neodymium, and samarium; the other metal element is selected from one or more of magnesium, calcium, barium, manganese, iron, nickel, cobalt, zinc, ruthenium, or titanium elements.

4. The preparation method of the catalyst according to any one of claims 1-3, comprising: (1) Dissolve the precursors of Cu and other elements to obtain an active component solution, and the active component solution contains chlorine element and does not contain P and S elements; (2) Disperse the precursor containing the carrier alumina in water to obtain a carrier slurry; (3) Under stirring, mix the active component solution and the carrier slurry to obtain a paste; (4) Add an aqueous solution containing P and S elements to the paste and stir to obtain a slurry; (5) Remove the water in the slurry to obtain a dry mixture; (6) Calcinate the dry mixture to obtain the catalyst.

5. The preparation method according to claim 4, wherein, The precursor containing the carrier alumina is selected from one or more of alumina or alumina hydrates, such as alumina powder, pseudo-boehmite, aluminum sol, boehmite, aluminum hydroxide, and other crystalline alumina or its precursors.

6. The preparation method according to claim 4 or 5, wherein The viscosity of the paste in step (3) > 6000 mPa·S.

7. The preparation method according to any one of claims 4-6, wherein, Optionally, add an acidic liquid to step (1) and / or (2) and / or (3) so that the pH of the finally obtained paste ≤ 5. Preferably, the acidic liquid is selected from one or two of nitric acid and hydrochloric acid.

8. The preparation method according to any one of claims 4-7, wherein, The viscosity of the slurry in step (4) is 1000-6000 mPa·S.

9. The preparation method according to any one of claims 4-8, wherein, The calcination temperature is 400-700 °C.

10. A method for preparing chlorine gas by hydrogen chloride oxidation, characterized in that, The catalyst used is the catalyst according to any one of claims 1-4.

Images