Regeneration method of hydrogen chloride oxidation catalyst and method for preparing chlorine through catalytic oxidation of hydrogen chloride

Abstract

The invention provides a regeneration method of a hydrogen chloride oxidation catalyst and a method for preparing chlorine through catalytic oxidation of hydrogen chloride, the hydrogen chloride oxidation catalyst comprises an active component containing ruthenium and a carrier for loading the active component, and the carrier contains titanium; the regeneration method comprises the following steps: carrying out first treatment on a hydrogen chloride oxidation catalyst to be regenerated by adopting a mixed atmosphere containing a halogen hydride gas and a gaseous hydroxyl donor; the gaseous hydroxyl donor comprises one or more of water, methanol and ethanol; and roasting the hydrogen chloride oxidation catalyst to be regenerated after the first treatment. One or more of water, methanol and ethanol are introduced into the atmosphere of the first treatment as a gaseous hydroxyl donor, and the existence of the gaseous hydroxyl donor enables the carrier of the hydrogen chloride oxidation catalyst to maintain a stable structure in the regeneration process and reduces Ti loss, so that the fundamental change of the performance of the catalyst after multiple times of regeneration can be effectively slowed down or even avoided, and the regeneration efficiency of the catalyst is improved. The chlorine production capacity of the catalyst is effectively improved and the chlorine production cost is reduced.

Description

Technical Field

[0001] The present application relates to the field of catalyst technology, and in particular to a method for regenerating a hydrogen chloride oxidation catalyst and a method for preparing chlorine by catalytic oxidation of hydrogen chloride. Background Art

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

[0003] Commonly used hydrogen chloride oxidation catalysts include Ru-based catalysts and Cu-based catalysts. Among them, Ru-based catalysts are prone to repeated activity decline during use. As the activity declines repeatedly, the hydrogen chloride oxidation catalyst needs to be regenerated multiple times. However, after multiple regenerations, the catalytic performance will be greatly reduced. Summary of the invention

[0004] Based on this, the present application provides a method for regenerating a hydrogen chloride oxidation catalyst and a method for producing chlorine by catalytic oxidation of hydrogen chloride, so as to achieve multiple regenerations of the hydrogen chloride oxidation catalyst, and still maintain a high catalytic performance after multiple regenerations, thereby improving the efficiency of producing chlorine by catalytic oxidation of hydrogen chloride.

[0005] The first aspect of the present application provides a method for regenerating a hydrogen chloride oxidation catalyst, wherein the hydrogen chloride oxidation catalyst comprises an active component containing a ruthenium element and a carrier for carrying the active component, wherein the carrier contains a titanium element; the regeneration method comprises the following steps:

[0006] The hydrogen chloride oxidation catalyst to be regenerated is first treated with a mixed atmosphere containing hydrogen halide gas and a gaseous hydroxyl donor; the gaseous hydroxyl donor includes one or more of water, methanol and ethanol;

[0007] The hydrogen chloride oxidation catalyst to be regenerated after the first treatment is subjected to a calcination treatment.

[0008] In some embodiments, the volume proportion of the gaseous hydroxyl donor in the mixed atmosphere is 0.1%-50%.

[0009] In some embodiments, the hydrogen halide gas includes one or more of hydrogen chloride and hydrogen bromide.

[0010] In some embodiments, the temperature of the first treatment is 200° C.-700° C., optionally 200° C.-500° C.; and / or

[0011] The first treatment time is 1h-200h.

[0012] In some embodiments, the support contains a titanium-containing compound, and the titanium-containing compound includes one or more of rutile titanium dioxide and anatase titanium dioxide.

[0013] In some embodiments, the titanium-containing compound includes a mixture of rutile titanium dioxide and anatase titanium dioxide, and the mass proportion of the anatase titanium dioxide in the mixture is 10%-60%.

[0014] In some embodiments, the active component includes one or more of ruthenium oxide and ruthenium oxychloride.

[0015] In some embodiments, the calcination temperature is 100°C-700°C, optionally 200°C-400°C; and / or

[0016] The calcination time is 1h-20h.

[0017] In some embodiments, the calcination process is performed in an oxygen-containing atmosphere, and the volume proportion of oxygen in the oxygen-containing atmosphere is 5%-100%.

[0018] One or more embodiments of the present application provide a method for preparing chlorine by catalytic oxidation of hydrogen chloride, wherein the catalyst used in the method is a hydrogen chloride oxidation catalyst, wherein the hydrogen chloride oxidation catalyst comprises an active component containing a ruthenium element and a carrier for carrying the active component, wherein the carrier contains a titanium element;

[0019] The method comprises: in the process of catalytic oxidation of hydrogen chloride to produce chlorine, using the regeneration method described in the first aspect of the present application to regenerate the hydrogen chloride oxidation catalyst with reduced catalytic activity.

[0020] In the above-mentioned method for regenerating the hydrogen chloride oxidation catalyst, one or more of water, methanol and ethanol are introduced into the first treatment atmosphere as a gaseous hydroxyl donor. The presence of the gaseous hydroxyl donor enables the carrier of the hydrogen chloride oxidation catalyst to maintain structural stability during the regeneration process, reduces Ti loss, and thus can effectively slow down or even avoid fundamental changes in catalyst performance after multiple regenerations, effectively improve the chlorine production capacity of the catalyst, and reduce the cost of chlorine production. DETAILED DESCRIPTION

[0021] For ease of understanding of the present invention, the application will be described more fully below with reference to relevant embodiments. The following provides preferred embodiments of the application. However, the application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the application more thorough and comprehensive.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0023] The terms "and / or", "or / and", and "and / or" used herein include any one of two or more related listed items, and also include any and all combinations of the related listed items, wherein the any and all combinations include any combination of two related listed items, any more related listed items, or all related listed items. It should be noted that when at least three items are connected by at least two conjunctions selected from "and / or", "or / and", and "and / or", it should be understood that in the present application, the technical solution undoubtedly includes technical solutions connected by "logical and", and also undoubtedly includes technical solutions connected by "logical or".

[0024] In the present application, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0025] In this application, when it comes to numerical ranges, unless otherwise specified, the above numerical ranges are deemed to be continuous and include the minimum and maximum values ​​of the range, as well as each value between such minimum and maximum values. Further, when a range refers to an integer, each integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe features or characteristics, the ranges can be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges included therein.

[0026] Only some numerical ranges are specifically disclosed herein. However, any lower limit can be combined with any upper limit to form an unspecified range; and any lower limit can be combined with other lower limits to form an unspecified range, and likewise any upper limit can be combined with any other upper limit to form an unspecified range. In addition, each separately disclosed point or single value can itself be combined as a lower limit or upper limit with any other point or single value or with other lower limits or upper limits to form an unspecified range.

[0027] The temperature parameters in this application, unless otherwise specified, allow both constant temperature treatment and treatment within a certain temperature range. The constant temperature treatment allows the temperature to fluctuate within the accuracy range controlled by the instrument. Fluctuations within the range of ±5°C, ±4°C, ±3°C, ±2°C, and ±1°C are allowed.

[0028] Herein, the “suitable” mentioned in “suitable combination”, “suitable method”, “any suitable method”, etc., shall be based on the ability to implement the technical solution of this application, solve the technical problems of this application, and achieve the expected technical effects of this application.

[0029] In the present application, "further", "further", "particularly" and the like are used for descriptive purposes to indicate differences in content, but should not be construed as limiting the scope of protection of the present application.

[0030] In this application, "optionally", "optional", and "optional" mean optional or dispensable, that is, any one of the two parallel schemes of "yes" or "no". If multiple "options" appear in a technical solution, unless otherwise specified and there is no contradiction or mutual restriction, each "optional" is independent.

[0031] In the description of the application, "plurality" means at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0032] If there is no special description, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution. If there is no special description, all technical features and optional technical features of the present application can be combined with each other to form a new technical solution.

[0033] If there is no special explanation, all the steps of the present application can be performed sequentially or randomly, preferably sequentially.

[0034] Commonly used hydrogen chloride oxidation catalysts include Ru-based catalysts and Cu-based catalysts. Ru-based catalysts are commonly used systems with ruthenium oxide or ruthenium oxychloride as active components supported on a Ti-containing carrier. The activity of Ru-based catalysts depends on the dispersibility of the Ru species on the carrier, and the Ti-containing carrier will affect the dispersibility of the Ru species. In actual application, due to the purity of the raw gas or the local temperature is too high, the Ru-based catalyst has the problem of decreased activity due to sulfur poisoning, growth of Ru active species particles and other factors during long-term use.

[0035] Patent application with publication number CN101977683B discloses a method for regenerating a catalyst containing ruthenium or a ruthenium compound poisoned by sulfur in the form of sulfur compounds, specifically subjecting the deactivated catalyst to treatment with a gas stream containing hydrogen halide under non-oxidative conditions, optionally at elevated temperature.

[0036] Patent application with publication number CN102271807B discloses a method for regenerating a catalyst containing ruthenium oxide for hydrogen chloride oxidation. The method comprises the following steps: a) reducing the catalyst at a temperature of 100° C. to 800° C. using a gas stream containing hydrogen chloride and an optional inert gas, and b) re-calcining the catalyst at a temperature of 150 to 800° C. using a gas stream containing oxygen.

[0037] Patent application with publication number CN115155672A discloses a method for regenerating a hydrogen chloride oxidation catalyst, which comprises first treating the catalyst in a mixed atmosphere of reducing gas and inert gas at 100°C-700°C; the reducing gas is a mixture of one or more of H2, CH3I, CH2I2 and CH4; and calcining the treated catalyst in a mixed gas flow of oxygen and inert gas at 100-700°C.

[0038] It can be seen that the related art mainly focuses on controlling the particle size of Ru or the content of S-containing compounds, and does not pay attention to the performance changes of the carrier during the regeneration process. However, the morphology of titanium dioxide will also change greatly after regeneration, and the loss of Ti element is more serious, which will cause the Ru active species particles to grow and the dispersion to deteriorate, and will also be accompanied by the loss of Ru element. Therefore, after multiple regenerations, the activity of Ru-based catalysts will drop significantly. Therefore, this application regenerates the catalyst from the perspective of reducing the loss of Ti element in the catalyst carrier, and after multiple regenerations, the catalyst still has a high activity.

[0039] One or more embodiments of the present application provide a method for regenerating a hydrogen chloride oxidation catalyst, wherein the hydrogen chloride oxidation catalyst comprises an active component containing a ruthenium element and a carrier for carrying the active component, wherein the carrier contains a titanium element; the regeneration method comprises the following steps:

[0040] The hydrogen chloride oxidation catalyst to be regenerated is subjected to a first treatment using a mixed atmosphere containing hydrogen halide gas and a gaseous hydroxyl donor; the gaseous hydroxyl donor includes one or more of water, methanol and ethanol; and the hydrogen chloride oxidation catalyst to be regenerated after the first treatment is subjected to a calcination treatment.

[0041] It can be understood that one or more of water, methanol and ethanol are introduced into the atmosphere of the first treatment as gaseous hydroxyl donors. The presence of the gaseous hydroxyl donor allows the carrier of the hydrogen chloride oxidation catalyst to maintain structural stability during the regeneration process, reduces Ti loss, and thus can effectively slow down or even avoid fundamental changes in catalyst performance after multiple regenerations, effectively improve the chlorine production capacity of the catalyst, and reduce the cost of chlorine production.

[0042] In some embodiments, the volume proportion of the gaseous hydroxyl donor in the mixed atmosphere is 0.1%-50%; for example, it can be but not limited to 0.1%, 1%, 2%, 4%, 6%, 8%, 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28%, 30%, 32%, 34%, 36%, 38%, 40%, 42%, 44%, 46%, 48%, 50% or the range between any two of the above volume proportions. When the volume proportion of the gaseous hydroxyl donor in the mixed atmosphere is within the above range, it is beneficial to effectively reduce the loss of Ti without affecting the catalyst activity recovery effect, and the catalyst regeneration effect is better.

[0043] As a possible implementation, the hydrogen halide gas includes one or more of hydrogen chloride and hydrogen bromide.

[0044] In some embodiments, the temperature of the first treatment is 200°C-700°C; for example, it may be but is not limited to 200°C, 220°C, 240°C, 260°C, 280°C, 300°C, 320°C, 340°C, 360°C, 380°C, 400°C, 420°C, 440°C, 460°C, 480°C, 500°C, 520°C, 540°C, 560°C, 580°C, 600°C, 620°C, 640°C, 660°C, 680°C, 700°C or a range between any two of the above temperatures.

[0045] In some optional embodiments, the temperature of the first treatment is 200°C-500°C.

[0046] As a possible implementation manner, the time of the first treatment is 1 hour to 200 hours. For example, it may be, but is not limited to, 1 hour, 10 hours, 20 hours, 30 hours, 40 hours, 50 hours, 60 hours, 70 hours, 80 hours, 90 hours, 100 hours, 110 hours, 120 hours, 130 hours, 140 hours, 150 hours, 160 hours, 170 hours, 180 hours, 190 hours, 200 hours, or a range between any two of the above times.

[0047] When the temperature and time of the first treatment are respectively within the above ranges, it is beneficial to further improve the regeneration effect of the catalyst.

[0048] It should be noted that the temperature and time of the first treatment can be combined in any appropriate manner, and both can be selected from any temperature and time of the first treatment described in this document.

[0049] As a non-limiting example, the mixed atmosphere further comprises a protective gas and / or an inert gas; optionally, the inert gas comprises one or more of nitrogen and argon; optionally, the protective gas comprises nitrogen.

[0050] In some embodiments, the support contains a titanium-containing compound, and the titanium-containing compound includes one or more of rutile titanium dioxide and anatase titanium dioxide.

[0051] As a possible implementation, the titanium-containing compound includes a mixture of rutile titanium dioxide and anatase titanium dioxide, and the mass proportion of anatase titanium dioxide in the mixture is 10%-60%; for example, it can be but not limited to 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60% or a range between any two of the above mass proportions, etc. As a result, the catalyst has good activity and stability.

[0052] In some embodiments, the active component includes one or more of ruthenium oxide and ruthenium oxychloride.

[0053] As a possible implementation mode, the temperature of the calcination treatment is 100°C-700°C; for example, it can be but not limited to 100°C, 120°C, 140°C, 160°C, 180°C, 200°C, 220°C, 240°C, 260°C, 280°C, 300°C, 320°C, 340°C, 360°C, 380°C, 400°C, 420°C, 440°C, 460°C, 480°C, 500°C, 520°C, 540°C, 560°C, 580°C, 600°C, 620°C, 640°C, 660°C, 680°C, 700°C or the range between any two of the above temperatures.

[0054] In some optional embodiments, the calcination temperature is 200°C-400°C.

[0055] In some embodiments, the calcination time is 1 h to 20 h, for example, but not limited to 1 h, 2 h, 3 h, 4 h, 5 h, 6 h, 7 h, 8 h, 9 h, 10 h, 11 h, 12 h, 13 h, 14 h, 15 h, 16 h, 17 h, 18 h, 19 h, 20 h, or a range between any two of the above times.

[0056] When the temperature and time of the calcination treatment are respectively within the above ranges, it is beneficial to further improve the regeneration effect of the catalyst without affecting the performance of the catalyst.

[0057] It should be noted that the temperature and time of the calcination treatment can be combined in any appropriate manner, and both can be selected from any temperature and time of the calcination treatment described in this article.

[0058] In some embodiments, the calcination treatment is carried out in an oxygen-containing atmosphere, and the volume percentage of oxygen in the oxygen-containing atmosphere is 5%-100%; for example, it can be but not limited to 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100% or the range between any two of the above volume percentages. When the volume percentage of oxygen in the oxygen-containing atmosphere is within the above range, the regeneration effect of the catalyst is better.

[0059] In some embodiments, the oxygen-containing atmosphere further comprises a protective gas and / or an inert gas; optionally, the inert gas comprises one or more of nitrogen and argon; optionally, the protective gas comprises nitrogen.

[0060] As a non-limiting example, the method for regenerating the hydrogen chloride oxidation catalyst is carried out in situ on a reactor for the catalytic oxidation of hydrogen chloride.

[0061] One or more embodiments of the present application provide a method for preparing chlorine by catalytic oxidation of hydrogen chloride, wherein the catalyst used in the method is a hydrogen chloride oxidation catalyst, wherein the hydrogen chloride oxidation catalyst comprises an active component containing a ruthenium element and a carrier for loading the active component, wherein the carrier comprises a titanium element; the method comprises: in the process of preparing chlorine by catalytic oxidation of hydrogen chloride, regenerating the hydrogen chloride oxidation catalyst with reduced catalytic activity by the above-mentioned hydrogen chloride oxidation catalyst regeneration method.

[0062] It should be noted that the "hydrogen chloride oxidation catalyst with reduced catalytic activity" mentioned above refers to a catalyst with reduced hydrogen chloride conversion rate compared with a freshly prepared hydrogen chloride oxidation catalyst. For example, the catalytic activity of the hydrogen chloride oxidation catalyst is reduced due to factors such as sulfur poisoning, long-term use or high-temperature sintering resulting in the growth of Ru active species particles.

[0063] The technical scheme of the present invention is described in detail below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. The experimental methods for which specific conditions are not specified in the following embodiments are preferably referred to the guidance given in the present invention, and can also be carried out according to the experimental manual or conventional conditions in the art, or according to the conditions recommended by the manufacturer, or with reference to experimental methods known in the art.

[0064] In the following specific embodiments, the measured parameters of raw material components may have slight deviations within the range of weighing accuracy unless otherwise specified. For temperature and time parameters, acceptable deviations caused by instrument test accuracy or operation accuracy are allowed.

[0065] The ruthenium trichloride used in the following embodiments and comparative examples was purchased from Yunnan Precious Metals New Materials Holding Group Co., Ltd., alumina powder was purchased from Zibo Chaoke Alumina Materials Co., Ltd., titanium dioxide was purchased from Yixing Qianye Non-metallic Materials Co., Ltd., titanium sol was purchased from Xuancheng Jingrui New Materials Co., Ltd., and hydroxypropyl methylcellulose was purchased from Anhui Shanhe Pharmaceutical Auxiliary Co., Ltd. The conventional metal salts used were all purchased from Xilong Chemical Co., Ltd., and other raw materials, unless otherwise specified, are all commercially available raw materials.

[0066] 1. Preparation of Hydrogen Chloride Oxidation Catalyst

[0067] 1. Preparation of Fresh Hydrogen Chloride Oxidation Catalyst

[0068] 60 parts by weight of titanium dioxide [30% rutile titanium dioxide], 100 parts by weight of α-alumina, 17.1 parts by weight of titanium oxide sol and 5 parts by weight of hypromellose were mixed, and then pure water was added for kneading to obtain a mixture. The mixture was extruded into a cylindrical shape with a diameter of 2.5 mm Φ and dried, and then crushed into a length of about 3 mm to 5 mm. The obtained molded body was placed in air and calcined at 750°C for 3 hours to obtain a carrier containing a mixture of titanium oxide and α-alumina.

[0069] The carrier was impregnated with an aqueous solution of ruthenium chloride and dried, and then calcined in air at 300°C for 2 hours to obtain a blue-gray supported ruthenium oxide with a loading rate of 1.5 wt% of ruthenium oxide on the carrier. The sulfur content of the supported ruthenium oxide (new catalyst) was 0.02 wt% by XRF analysis.

[0070] 2. Preparation of the Hydrogen Chloride Oxidation Catalyst to be Treated

[0071] Fresh hydrogen chloride oxidation catalyst was filled into the reactor. Then, hydrogen chloride (containing SO2 11mg / m 3 ) and oxygen are supplied to the reactor for oxidation reaction, thereby preparing the to-be-treated hydrogen chloride oxidation catalyst. The to-be-treated hydrogen chloride oxidation catalyst is taken out and analyzed by XRF, and its sulfur content is 0.18wt%, indicating that the to-be-treated hydrogen chloride oxidation catalyst is successfully prepared.

[0072] 2. Regeneration of the Hydrogen Chloride Hydrogenation Catalyst to be Treated

[0073] Example 1

[0074] 8 g of the above-prepared hydrogen chloride oxidation catalyst to be treated was filled in a fixed bed reactor, and 56 mL / min of HCl and 5 mL / min of water vapor were introduced at 380° C. to treat the catalyst for 75 hours, and then the catalyst was calcined for 2 hours by switching to an air atmosphere of 56 mL / min to complete the regeneration of the hydrogen chloride oxidation catalyst to be treated. During the regeneration process, the tail end of the reactor was clean, and no obvious yellow volatiles were generated.

[0075] Example 2

[0076] 8 g of the above-prepared hydrogen chloride oxidation catalyst to be treated was filled in a fixed bed reactor, and 56 mL / min of HCl and 2 mL / min of ethanol were introduced at 380°C to treat the catalyst for 75 hours, and then the catalyst was calcined for 2 hours by switching to an air atmosphere of 56 mL / min to complete the regeneration of the hydrogen chloride oxidation catalyst to be treated. During the regeneration process, the tail end of the reactor was clean, and no obvious yellow volatiles were generated.

[0077] Example 3

[0078] 8 g of the above-prepared hydrogen chloride oxidation catalyst to be treated was filled in a fixed bed reactor, and 56 mL / min of HCl and 3 mL / min of methanol were introduced at 380°C to treat the catalyst for 75 hours, and then the catalyst was calcined for 2 hours by switching to an air atmosphere of 56 mL / min to complete the regeneration of the hydrogen chloride oxidation catalyst to be treated. During the regeneration process, the tail end of the reactor was clean, and no obvious yellow volatiles were generated.

[0079] Example 4

[0080] 8 g of the above-prepared hydrogen chloride oxidation catalyst to be treated was filled in a fixed bed reactor, and 56 mL / min of HCl and 0.56 mL / min of water vapor were introduced at 380° C. to treat the catalyst for 200 hours, and then the catalyst was calcined for 2 hours by switching to an air atmosphere of 56 mL / min to complete the regeneration of the hydrogen chloride oxidation catalyst to be treated. During the regeneration process, the tail end of the reactor was clean, and no obvious yellow volatiles were generated.

[0081] Example 5

[0082] 8 g of the above-prepared hydrogen chloride oxidation catalyst to be treated was filled in a fixed bed reactor, and 56 mL / min of HCl and 56 mL / min of water vapor were introduced at 380°C to treat the catalyst for 200 hours, and then the catalyst was calcined for 2 hours by switching to an air atmosphere of 56 mL / min to complete the regeneration of the hydrogen chloride oxidation catalyst to be treated. During the regeneration process, the tail end of the reactor was clean, and no obvious yellow volatiles were generated.

[0083] Example 6

[0084] 8 g of the above-prepared hydrogen chloride oxidation catalyst to be treated was filled in a fixed bed reactor, and 56 mL / min of HCl and 5 mL / min of water vapor were introduced at 200° C. to treat the catalyst for 200 hours, and then the catalyst was calcined for 20 hours by switching to an air atmosphere of 56 mL / min to complete the regeneration of the hydrogen chloride oxidation catalyst to be treated. During the regeneration process, the tail end of the reactor was clean, and no obvious yellow volatiles were generated.

[0085] Example 7

[0086] 8 g of the above-prepared hydrogen chloride oxidation catalyst to be treated was filled in a fixed bed reactor, and 56 mL / min of HCl and 10 mL / min of water vapor were introduced at 500° C. to treat the catalyst for 10 hours, and then the catalyst was calcined for 1.5 hours by switching to an air atmosphere of 56 mL / min to complete the regeneration of the hydrogen chloride oxidation catalyst to be treated. During the regeneration process, the tail end of the reactor was clean, and no obvious yellow volatiles were generated.

[0087] Example 8

[0088] 8 g of the above-prepared hydrogen chloride oxidation catalyst to be treated was filled in a fixed bed reactor, and 56 mL / min of HCl and 10 mL / min of water vapor were introduced at 700°C to treat the catalyst for 2 hours, and then the catalyst was calcined for 1 hour by switching to an air atmosphere of 56 mL / min to complete the regeneration of the hydrogen chloride oxidation catalyst to be treated. During the regeneration process, the tail end of the reactor was clean, and no obvious yellow volatiles were generated.

[0089] Comparative Example 1

[0090] The difference between Comparative Example 1 and Examples 1-3 is that in the first treatment process, no water vapor, ethanol or methanol is introduced, and only HCl is introduced; the specific process is as follows:

[0091] 8 g of the above-prepared hydrogen chloride oxidation catalyst to be treated was filled in a fixed bed reactor, and 56 mL / min of HCl was introduced into the catalyst at 380°C for 75 hours, and then the catalyst was calcined for 2 hours by switching to an air atmosphere of 56 mL / min to complete the regeneration of the hydrogen chloride oxidation catalyst to be treated. During the regeneration process, a yellow precipitate was present at the tail end of the reactor, and the yellow precipitate was analyzed to be a compound containing Ti and Cl.

[0092] Comparative Example 2

[0093] 1 g of the hydrogen chloride oxidation catalyst to be treated was placed in a quartz reaction tube (10 mm in diameter) and a gas mixture consisting of 1 L / h hydrogen chloride and 5 L / h nitrogen was flowed at 380° C. for 14 hours to complete catalyst regeneration. During the regeneration process, a yellow precipitate was present at the tail end of the reactor, and the yellow precipitate was analyzed to be a compound containing Ti and Cl.

[0094] Comparative Example 3

[0095] 21g of the above-prepared hydrogen chloride oxidation catalyst to be treated was placed in a fluidized bed reactor with a bed height of 2.5m, and 10.0kg / h of HCl and 0.9kg / h of N2 were flowed through the catalyst at 400°C; after 20h, the catalyst was calcined at 400°C in 2.0kg / h of O2 and 8.0kg / h of N2 for 30 minutes to complete the regeneration of the catalyst. During the regeneration process, a yellow precipitate was present at the tail end of the reactor, and the yellow precipitate was analyzed to be a compound containing Ti and Cl.

[0096] Comparative Example 4

[0097] Take 4g of the above-prepared hydrogen chloride oxidation catalyst to be treated, pass a mixed gas of CH3I and N2 (CH3I volume fraction is 40%, the rest is N2), the flow rate is 200mL / min, the heating temperature is 320℃, and keep it for 1.5h; then close the H2 gas line, keep N2 replacement for 10min, increase the heating temperature to 360℃, pass 10ml / min of O2 and keep it for 3.0h to complete the regeneration of the catalyst. During the regeneration process, there is a reddish-brown precipitate at the tail end of the reactor. The yellow precipitate is analyzed to be a compound containing Ti and I.

[0098] For the hydrogen chloride oxidation catalyst regenerated by the methods of the above embodiments and comparative examples, refer to "2. Preparation of hydrogen chloride oxidation catalyst to be treated" to continue to prepare a catalyst with reduced activity, and perform a second regeneration by referring to the methods of the above embodiments and comparative examples respectively; cycle the above treatment, perform a third regeneration, and record the conversion rate and Ru content after the third regeneration.

[0099] 3. Catalytic performance test

[0100] 1. The regenerated hydrogen chloride oxidation catalyst to be treated in the above embodiments and comparative examples was subjected to catalytic oxidation of hydrogen chloride to produce chlorine to test the catalytic performance, and a fresh hydrogen chloride oxidation catalyst was used as a control.

[0101] The method for preparing chlorine by catalytic oxidation of hydrogen chloride is as follows:

[0102] Weigh 8g of catalyst and put it into a fixed bed reactor. Control the volume ratio of hydrogen chloride to oxygen to 2 / 1. When the mass space velocity of HCl is 0.7h -1The reaction of catalytic oxidation of hydrogen chloride to produce chlorine was carried out under the conditions of reaction temperature of 360°C and reaction pressure of 0.3 MPa (absolute pressure). After continuous reaction for 20 hours, sampling and analysis were performed to obtain catalyst conversion rate data.

[0103] The test method for hydrogen chloride conversion is as follows:

[0104] (1) Detection principle

[0105] Cl2+2KI=2KCl+I2

[0106] I2+2 Na2S2O3=2NaI+Na2S4O6

[0107] HCl+NaOH=NaCl+H2O

[0108] (2) Preparation and calibration of 0.1 mol / L Na2S2O3 solution

[0109] Weigh about 6.2g of Na2S2O3·5H2O, dissolve it in an appropriate amount of freshly boiled and cooled distilled water (to remove O2 and CO2 in the water), add 0.1g Na2CO3 (to inhibit microbial growth), make a 250mL solution, and store it in a brown bottle in a dark place; calibrate it after 2 weeks.

[0110] Accurately weigh 0.15g K2Cr2O7 (dried at 110℃ for 2h) in an iodine volumetric flask, add 20mL water to dissolve, add 2gKI and 10mL H2SO4 with a mass concentration of 1wt%, shake well and let stand for 5 minutes, then add 50mL water to dilute, titrate with Na2S2O3 solution until the solution turns light yellow-green, add 2mL starch indicator, and continue titrating with Na2S2O3 solution until the solution changes from blue to light green (the end point is Cr 3+ The calibration was performed three times in parallel and the average value was taken.

[0111] (3) Analysis and testing process

[0112] a) Sampling: Replace the 250mL sampling bottle with the sample gas to be tested for 3 minutes (gas enters from the bottom and exits from the top), ensuring that there are no impurities in the sampling bottle. The sample gas in the sampling bottle is fully reacted with a 15wt% KI aqueous solution. The Cl2 in the sample gas reacts with KI to generate I2 (I3 - The HCl is dissolved in the absorption liquid in the form of HCl. If I2 precipitation occurs, it will easily lead to poor results and resampling is required. HCl is absorbed to form a hydrochloric acid aqueous solution. Then titration is performed.

[0113] b) I2 (I3 -) titration: Take out 25.00mL of absorption solution into a 250mL conical flask, dilute with 50mL of distilled water, and titrate with the prepared and calibrated Na2S2O3 solution until it turns light yellow. Add 2mL of starch solution and continue titrating until the blue color just disappears, which is the end point. Record the volume of Na2S2O3 solution consumed in the titration, and you can calculate the I2 (I3 - ) content, and then calculate the amount of Cl2 in the sample gas to be tested.

[0114] c) Titration of hydrochloric acid in the absorption liquid: Add 2-3 drops of phenolphthalein reagent to the sample that has been titrated in step b). The colorless liquid turns red, and the red does not change color within half a minute (if it does not turn from colorless to red, it means that there is no hydrochloric acid in the absorption liquid, provided that the experimental process is correct). Then titrate with the prepared and calibrated NaOH standard solution until it is colorless, which is the titration end point. Record the volume of NaOH standard solution consumed in the titration, and you can calculate the H in the absorption liquid. + The content of HCl in the sample gas to be tested can be calculated.

[0115] (4) Calculate the conversion rate of hydrogen chloride in the sample Conv:

[0116]

[0117] Where: a represents the concentration of Na2S2O3 solution, mol / L; b represents the volume of Na2S2O3 solution consumed in titration, mL; c represents the concentration of NaOH standard solution, mol / L; d represents the volume of NaOH standard solution consumed in titration, mL.

[0118] The test results are shown in Table 1.

[0119] 2. ICP test was used to quantitatively analyze the Ru content and Ti loss of the hydrogen chloride oxidation catalyst to be treated after regeneration in the above embodiments and comparative examples. The results are shown in Table 1.

[0120] Table 1

[0121]

[0122] From the results of Examples 1-8 and Comparative Examples 1-4 in Table 1, it can be seen that compared with Comparative Examples 1-4, the Ti loss rate in Examples 1-8 is significantly reduced, and the catalyst still maintains a high activity after 3 regenerations, and the Ru loss rate is lower. This shows that when the hydrogen chloride oxidation catalyst is regenerated, introducing one or more of water, methanol and ethanol as a gaseous hydroxyl donor in the first treated atmosphere can effectively reduce Ti loss, so that the performance of the hydrogen chloride oxidation catalyst does not change significantly after multiple regenerations, and the chlorine production capacity of the catalyst is effectively improved.

[0123] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0124] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for regenerating a hydrogen chloride oxidation catalyst, characterized in that: The hydrogen chloride oxidation catalyst comprises an active component containing a ruthenium element and a carrier for carrying the active component, wherein the carrier contains a titanium element; and the regeneration method comprises the following steps: The hydrogen chloride oxidation catalyst to be regenerated is first treated with a mixed atmosphere containing hydrogen halide gas and a gaseous hydroxyl donor; the gaseous hydroxyl donor includes one or more of water, methanol and ethanol; The hydrogen chloride oxidation catalyst to be regenerated after the first treatment is subjected to a calcination treatment.

2. The regeneration method according to claim 1, characterized in that: The volume proportion of the gaseous hydroxyl donor in the mixed atmosphere is 0.1%-50%.

3. The regeneration method according to claim 1, characterized in that: The hydrogen halide gas includes one or more of hydrogen chloride and hydrogen bromide.

4. The regeneration method according to claim 1, characterized in that: The temperature of the first treatment is 200°C-700°C, and can be 200°C-500°C; and / or The first treatment time is 1h-200h.

5. The regeneration method according to claim 1, characterized in that: The carrier contains a titanium compound, and the titanium compound includes one or more of rutile titanium dioxide and anatase titanium dioxide.

6. The regeneration method according to claim 5, characterized in that: The titanium-containing compound includes a mixture of rutile titanium dioxide and anatase titanium dioxide, and the mass proportion of the anatase titanium dioxide in the mixture is 10%-60%.

7. The regeneration method according to claim 1, characterized in that: The active component includes one or more of ruthenium oxide and ruthenium oxychloride.

8. The regeneration method according to any one of claims 1 to 7, characterized in that: The calcination temperature is 100°C-700°C, and can be 200°C-400°C; and / or The calcination time is 1h-20h.

9. The regeneration method according to any one of claims 1 to 7, characterized in that: The calcination process is carried out in an oxygen-containing atmosphere, wherein the volume proportion of oxygen in the oxygen-containing atmosphere is 5%-100%.

10. A method for preparing chlorine by catalytic oxidation of hydrogen chloride, characterized in that: The catalyst used in the method is a hydrogen chloride oxidation catalyst, which includes an active component containing a ruthenium element and a carrier for supporting the active component, wherein the carrier contains a titanium element; The method comprises: in the process of catalytic oxidation of hydrogen chloride to produce chlorine, regenerating the hydrogen chloride oxidation catalyst with reduced catalytic activity by using the regeneration method according to any one of claims 1 to 9.

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