CN108187671B - Regeneration method of aluminum oxide loaded platinum-tin dehydrogenation catalyst - Google Patents

Regeneration method of aluminum oxide loaded platinum-tin dehydrogenation catalyst Download PDF

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CN108187671B
CN108187671B CN201810007974.0A CN201810007974A CN108187671B CN 108187671 B CN108187671 B CN 108187671B CN 201810007974 A CN201810007974 A CN 201810007974A CN 108187671 B CN108187671 B CN 108187671B
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catalyst
gas
volume content
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chlorination
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CN108187671A (en
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潘相米
韩伟
谭亚南
吴砚会
何霖
程牧曦
艾珍
王�华
郑敏
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Southwest Research and Desigin Institute of Chemical Industry
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
    • B01J23/54—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
    • B01J23/56—Platinum group metals
    • B01J23/62—Platinum group metals with gallium, indium, thallium, germanium, tin or lead
    • B01J23/622—Platinum group metals with gallium, indium, thallium, germanium, tin or lead with germanium, tin or lead
    • B01J23/626—Platinum group metals with gallium, indium, thallium, germanium, tin or lead with germanium, tin or lead with tin
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/90—Regeneration or reactivation
    • B01J23/96—Regeneration or reactivation of catalysts comprising metals, oxides or hydroxides of the noble metals
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J38/00—Regeneration or reactivation of catalysts, in general
    • B01J38/02—Heat treatment
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J38/00—Regeneration or reactivation of catalysts, in general
    • B01J38/04—Gas or vapour treating; Treating by using liquids vaporisable upon contacting spent catalyst
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J38/00—Regeneration or reactivation of catalysts, in general
    • B01J38/04—Gas or vapour treating; Treating by using liquids vaporisable upon contacting spent catalyst
    • B01J38/42—Gas or vapour treating; Treating by using liquids vaporisable upon contacting spent catalyst using halogen-containing material
    • B01J38/44—Gas or vapour treating; Treating by using liquids vaporisable upon contacting spent catalyst using halogen-containing material and adding simultaneously or subsequently free oxygen; using oxyhalogen compound

Abstract

The invention provides a regeneration method of an aluminum oxide loaded platinum-tin dehydrogenation catalyst, belonging to the technical field of catalyst regeneration. The regeneration method comprises the steps of carbon burning chlorination and reduction: the carbon burning chlorination is to contact the deactivated catalyst with a regeneration gas to carry out carbon burning and chlorination; in the reduction step, the catalyst after carbon burning and chlorination treatment is contacted with a reducing gas to reduce the catalyst, and a catalyst bed layer is purged by nitrogen when the reduction is finished, so that the volume content of hydrogen in the system is reduced to be less than 0.5 percent. The regeneration method of the invention realizes carbon burning and chlorination simultaneously, and has the advantages that: firstly, in the presence of a chlorinating agent, excessive sintering of local active metal atoms caused by independent carbon burning can be avoided, the activity of the regenerated catalyst is improved, and the service life of the catalyst is prolonged; secondly, the simultaneous carbon burning and chlorination can shorten the treatment time and reduce the energy waste compared with the separate operation.

Description

Regeneration method of aluminum oxide loaded platinum-tin dehydrogenation catalyst
Technical Field
The invention belongs to the technical field of catalyst regeneration, and particularly relates to a regeneration method of an aluminum oxide supported platinum-tin dehydrogenation catalyst.
Background
Light olefins, especially propylene, are a very important basic chemical raw material. The propylene is mainly used for synthesizing products such as polypropylene, acrylonitrile, propylene oxide, isopropyl benzene and the like. The traditional propylene is mainly prepared from byproducts generated in the preparation of ethylene by steam cracking, and the traditional propylene production process cannot meet the market demand along with the continuous increase of the market demand on propylene products. At present, more than ten sets of Oleflex propane dehydrogenation propylene preparation devices are introduced. In scientific research colleges and universities in China, the research and development of the catalyst for preparing propylene by propane dehydrogenation are carried out successively, and the matched process is developed.
The process for preparing propylene by propane dehydrogenation takes propane with abundant resources and economy as a raw material to prepare propylene, and the dehydrogenation catalyst can adopt aluminum oxide loaded platinum tin and adopts the processes of a moving bed, a fixed bed, a fluidized bed and the like.
Because the processes for preparing propylene by propane dehydrogenation are carried out in a high-temperature environment of 550-700 ℃, the catalyst adopting aluminum oxide to load platinum tin gradually loses activity due to carbon deposition on the surface of the catalyst and on a pore passage and platinum tin agglomeration. Therefore, the catalyst generally needs to be regenerated after ten to fifteen days of operation. The regeneration aims to remove carbon deposition on the surface of the catalyst and in a pore channel, so that agglomerated platinum and tin atoms are re-dispersed, and the aim of recovering the activity of the catalyst is fulfilled. The selectivity and the conversion rate of the propane are improved, the service life of the catalyst is prolonged, and the enterprise benefit is increased.
Disclosure of Invention
The invention aims to solve the problem that the aluminum oxide supported platinum tin catalyst used for preparing propylene by propane dehydrogenation gradually loses activity due to carbon deposition on the surface of the catalyst and on a pore passage and platinum tin agglomeration. Provides a regeneration method of a dehydrogenation catalyst of aluminum oxide loaded platinum tin.
The purpose of the invention is realized by the following technical scheme:
a regeneration method of an aluminum oxide supported platinum tin dehydrogenation catalyst comprises the steps of carbon burning chlorination and reduction:
the carbon burning chlorination is to contact the inactivated catalyst with a regeneration gas to carry out carbon burning and chlorination, a catalyst bed layer is swept by nitrogen when the carbon burning chlorination is finished, the volume content of oxygen in a system is controlled to be lower than 0.2%, and the volume content of a chlorinating agent is controlled to be lower than 0.1%;
in the reduction step, the catalyst after carbon burning and chlorination treatment is contacted with a reducing gas to reduce the catalyst, and a catalyst bed layer is purged by nitrogen when the reduction is finished, so that the volume content of hydrogen in the system is reduced to be less than 0.5 percent.
As an embodiment of the regeneration method of the aluminum oxide supported platinum tin dehydrogenation catalyst, the deactivated catalyst is a catalyst for preparing propylene by dehydrogenation of aluminum oxide supported platinum tin propane.
As an embodiment of the method for regenerating an alumina-supported platinum-tin dehydrogenation catalyst according to the present invention, the regeneration gas includes air, nitrogen and a chlorinating agent; wherein the chlorinating agent is one or more of monochloromethane, dichloromethane, trichloromethane, carbon tetrachloride, dichloroethane, trichloroethane and tetrachloroethane.
As an embodiment of the regeneration method of the aluminum oxide supported platinum-tin dehydrogenation catalyst, the volume content of oxygen in the regeneration gas is 0.5-21%; the volume content of the chlorinating agent is 0.5-10%, preferably 2-8%.
As an embodiment of the regeneration method of the aluminum oxide supported platinum-tin dehydrogenation catalyst, the reducing gas is nitrogen and hydrogen, wherein the volume content of the hydrogen is 1-100%, and preferably 20-70%.
As an embodiment of the regeneration method of the aluminum oxide supported platinum-tin dehydrogenation catalyst, the space velocity of the regeneration gas is 500-10000 h-1Preferably 1000 to 5000 hours-1(ii) a The space velocity of the reducing gas is 500-10000 h-1Preferably 1000 to 5000 hours-1。
As an embodiment of the regeneration method of the aluminum oxide supported platinum-tin dehydrogenation catalyst, the temperature of a catalyst bed in the carbon burning chlorination step is 400-600 ℃, and the treatment time is 24-72 hours; in the reduction step, the temperature of a catalyst bed layer is 400-520 ℃, and the treatment time is 4-24 hours.
As an embodiment of the regeneration method of the aluminum oxide supported platinum-tin dehydrogenation catalyst, in the step of carbon burning chlorination, the volume content of oxygen in the regeneration gas is increased from 0.5-1%, the content of a chlorinating agent is 2-8%, and the gas space velocity is 1000-5000 h-1The method comprises the following specific operations:
1) the temperature of a catalyst bed layer is 400-500 ℃, the volume content of oxygen is 0.5-1%, the volume content of a chlorinating agent is 2-8%, and the air speed of gas is 1000-5000 h-1Treating for 6-18 hours;
2) the temperature of a catalyst bed layer is 450-500 ℃, the volume content of oxygen is 1-5%, the volume content of a chlorinating agent is 2-8%, and the air speed of gas is 1000-5000 h-1Treating for 6-18 hours;
3) the temperature of a catalyst bed layer is 480-550 ℃, the volume content of oxygen is 5-10%, the volume content of a chlorinating agent is 2-8%, and the air speed of gas is 1000-5000 h-1Treating for 6-18 hours;
4) the temperature of a catalyst bed layer is 480-600 ℃, the volume content of oxygen is 10-21%, the volume content of a chlorinating agent is 2-8%, and the air speed of gas is 1000-5000 h-1And treating for 6-18 hours.
In the reduction step, the volume content of hydrogen in the reduction gas is increased from 1-5%, and the gas space velocity is 1000-5000 h-1The method comprises the following specific operations:
1) the temperature of a catalyst bed layer is 400-450 ℃, the volume content of hydrogen is 1-5%, and the air speed of gas is 1000-5000 h-1Treating for 1-6 hours;
2) the temperature of a catalyst bed layer is 450-500 ℃, the volume content of hydrogen is 5-20%, and the air speed of gas is 1000-5000 h-1Treating for 1-6 hours;
3) the temperature of a catalyst bed layer is 450-520 ℃, the volume content of hydrogen is 20-50%, and the air speed of gas is 1000-5000 h-1Treating for 1-6 hours;
4) the temperature of the catalyst bed layer is 450-520 ℃, and the volume content of hydrogen is50-100% and gas space velocity of 1000-5000 h-1And treating for 1-6 hours.
Compared with the prior art, the invention has the following beneficial effects:
the regeneration method of the dehydrogenation catalyst in the prior art is carried out by separately burning carbon and chlorinating, and the regeneration method of the invention simultaneously realizes burning carbon and chlorinating and has the advantages that: firstly, in the presence of a chlorinating agent, excessive sintering of local active metal atoms caused by independent carbon burning can be avoided, the activity of the regenerated catalyst is improved, and the service life of the catalyst is prolonged; secondly, the simultaneous carbon burning and chlorination can shorten the treatment time and reduce the energy waste compared with the separate operation.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
The method for regenerating the alumina-supported platinum-tin catalyst according to the present invention will be described in detail below with reference to specific operation processes and principles.
A regeneration method of an aluminum oxide supported platinum tin dehydrogenation catalyst comprises the steps of carbon burning chlorination and reduction:
the carbon burning chlorination is to contact the inactivated catalyst with a regeneration gas to carry out carbon burning and chlorination, a catalyst bed layer is swept by nitrogen when the carbon burning chlorination is finished, and the volume content of oxygen in a system is controlled to be lower than 0.2 percent and the volume content of a chlorinating agent is controlled to be lower than 0.1 percent.
Specifically, the deactivated aluminum oxide supported platinum tin dehydrogenation catalyst is contacted with a regeneration gas to carry out carbon burning and chlorination treatment. In the carbon burning chlorination process, the bed temperature of the catalyst is kept to be 400-600 ℃, the treatment time is 24-72 hours, and the space velocity of the regeneration gas is 500-10000 hours-1Preferably 1000 to 5000 hours-1. And (3) blowing the catalyst bed layer with nitrogen after the carbon burning chlorination is finished, and controlling the volume content of oxygen in the system to be lower than 0.2 percent and the volume content of the chlorinating agent to be lower than 0.1 percent.
The regeneration method of the dehydrogenation catalyst in the prior art is carried out by separately burning carbon and chlorinating, and the regeneration method of the invention simultaneously realizes burning carbon and chlorinating and has the advantages that: firstly, in the presence of a chlorinating agent, excessive sintering of local active metal atoms caused by independent carbon burning can be avoided, the activity of the regenerated catalyst is improved, and the service life of the catalyst is prolonged; secondly, the simultaneous carbon burning and chlorination can shorten the treatment time and reduce the energy waste compared with the separate operation.
During the burning of carbon, the active metal atoms are oxidized, so that the burning of carbon actually includes the step of oxidation. The carbon burning and the chlorination are carried out simultaneously, the chlorine has the function of dispersing active metal atoms, and the chlorination effect is better when oxygen exists. When the carbon burning chlorination is finished, nitrogen is used for replacing, the content of oxygen and the content of a chlorinating agent are respectively reduced to be below 0.2% and 0.1%, the dechlorination effect can be achieved in the process, and the nitrogen is used for purging when the carbon burning chlorination is finished. Therefore, this application will burn the charcoal and chloridize and go on simultaneously, adopts comparatively simple processing mode to realize burning carbon, oxidation, chlorination and dechlorination simultaneously, compares and to show improvement regeneration efficiency in prior art, avoids simultaneously that the local active metal atom that burns the charcoal and lead to alone to be excessively sintered, improves the activity of catalyst after the regeneration.
Further, the deactivated catalyst is a catalyst for preparing propylene by dehydrogenation of aluminum oxide loaded platinum tin propane.
For the purposes of carbon burning and chlorination, the regeneration gas herein is preferably a gas comprising air, nitrogen and a chlorinating agent. Wherein the volume content of the oxygen is 0.5-21%; the volume content of the chlorinating agent is 0.5-10%, preferably 2-8%. The volume content of the oxygen is 0.5-21% because the upper limit of the oxygen content in the air is 21%, and the oxygen is required to be prepared when the oxygen is higher, and the requirement and the danger of a pipeline are higher when the oxygen is used in industrial practice. For this purpose, an upper limit of the oxygen content of 21% is selected. In addition, air is also inexpensive from an economic standpoint.
Further, the chlorinating agent is one or more of methane chloride, methylene dichloride, trichloromethane, carbon tetrachloride, dichloroethane, trichloroethane and tetrachloroethane.
According to the catalyst regeneration method, when carbon burning and chlorination treatment are carried out at the beginning, the oxygen content is not too high, otherwise, a catalyst bed layer is easy to generate temperature runaway, and the catalyst structure is damaged permanently. Therefore, it is preferable to control the oxygen content to 0.5 to 1% at the beginning. In the whole carbon burning and chlorination link, the catalyst bed layer is controlled at 400-600 ℃, and the air speed of the gas is controlled at 500-0000 h-1Preferably 1000 to 5000 hours-1. Meanwhile, the contact time is controlled to be 24-72 hours, the contact time is too short, carbon burning is incomplete, and platinum and tin are not completely dispersed; too long, especially at high oxygen levels, can result in re-agglomeration of the dispersed platinum tin. Therefore, the inventor selects a more ideal carbon burning and chlorination procedure as a multi-stage procedure through a plurality of experiments: burning carbon and chloridizing from a lower temperature and a lower oxygen content, and firstly burning the carbon on the surface of the catalyst; then heating to burn off the carbon deposit in the catalyst pore channel; with the reduction of the carbon content, the oxygen content is gradually increased, so that the accumulated carbon is burnt, the proportion of the chlorinating agent is changed less obviously in the whole process, and the volume ratio of the chlorinating agent is controlled to be 0.5-10%, preferably 2-8%. And then, blowing the catalyst bed layer with nitrogen, controlling the oxygen content to be lower than 0.2 percent, controlling the chlorinating agent content to be lower than 0.1 percent, and controlling the oxygen content and the chlorinating agent content to be too high to influence the subsequent reduction link. For example, high oxygen levels can lead to excessive local temperatures during reduction; the content of the chlorinating agent is too high, and HCl generated during reduction can corrode pipelines and equipment.
The specific operation of the carbon burning and chlorination segmentation procedure is as follows:
1) the temperature of a catalyst bed layer is 400-500 ℃, the volume content of oxygen is 0.5-1%, the volume content of a chlorinating agent is 2-8%, and the air speed of gas is 1000-5000 h-1Treating for 6-18 hours;
2) the temperature of a catalyst bed layer is 450-500 ℃, the volume content of oxygen is 1-5%, the volume content of a chlorinating agent is 2-8%, and the air speed of gas is 1000-5000 h-1Treating for 6-18 hours;
3) the temperature of a catalyst bed layer is 480-550 ℃, and oxygen is addedThe volume content of the gas is 5-10%, the volume content of the chlorinating agent is 2-8%, and the air speed of the gas is 1000-5000 h-1Treating for 6-18 hours;
4) the temperature of a catalyst bed layer is 480-600 ℃, the volume content of oxygen is 10-21%, the volume content of a chlorinating agent is 2-8%, and the air speed of gas is 1000-5000 h-1Treating for 6-18 hours;
5) blowing the catalyst bed layer with nitrogen gas to control the oxygen content below 0.2% and the chlorinating agent content below 0.1%.
In the reduction step, the catalyst after carbon burning and chlorination treatment is contacted with a reducing gas to reduce the catalyst, and a catalyst bed layer is purged by nitrogen when the reduction is finished, so that the volume content of hydrogen in the system is reduced to be less than 0.5 percent.
The reducing gas acts to change the metal in the oxidized state to an active state, such as a zero valent metal state. The hydrogen content is reduced because of the overall design requirements of the corresponding propane dehydrogenation to propylene catalyst device.
Specifically, the temperature of a catalyst bed layer is kept to be 400-520 ℃ in the reduction process, the treatment time is 4-24 hours, and the space velocity of the reduction gas is 500-10000 hours-1Preferably 1000 to 5000 hours-1。
Further, the reducing gas is nitrogen and hydrogen, wherein the volume content of the hydrogen is 1-100%.
After the deactivated catalyst is subjected to carbon burning and chlorination treatment, reducing gas is contacted with the catalyst. When the reduction treatment is carried out at the beginning, the hydrogen content and the temperature are not easy to be too high, the hydrogen content is controlled to be 1-5%, and the temperature is preferably controlled to be 400-450 ℃.
The specific operation of the reduction segmentation procedure is as follows:
1) the temperature of a catalyst bed layer is 400-450 ℃, the volume content of hydrogen is 1-5%, and the air speed of gas is 1000-5000 h-1Treating for 1-6 hours;
2) the temperature of a catalyst bed layer is 450-500 ℃, the volume content of hydrogen is 5-20%, and the air speed of gas is 1000-5000 h-1Treating for 1-6 hours;
3) temperature of catalyst bedThe temperature is 450-520 ℃, the volume content of hydrogen is 20-50%, and the gas space velocity is 1000-5000 h-1Treating for 1-6 hours;
4) the temperature of a catalyst bed layer is 450-520 ℃, the volume content of hydrogen is 50-100%, and the air speed of gas is 1000-5000 h-1Treating for 1-6 hours;
5) at the end of the reduction, the catalyst bed was purged with nitrogen to reduce the system hydrogen to below 0.5%.
The aluminum oxide supported platinum-tin dehydrogenation catalyst of the present invention will be further described with reference to specific examples.
Example 1
After the catalyst for preparing propylene by dehydrogenation of aluminum oxide-supported platinum tin propane is deactivated (the conversion rate of propane is lower than 15% or the selectivity of propylene is lower than 85%), the catalyst is regenerated. The temperature of the catalyst bed layer is reduced to 400 ℃, regeneration treatment gas is introduced, wherein the oxygen content is 0.5 percent, the chlorinating agent content is 5 percent, and the gas space velocity is 2000-1Treating for 10 hours; then the temperature of the catalyst bed layer is raised to 450 ℃, the oxygen content is raised to 3 percent, the content of the chlorinating agent, namely the chloromethane, is maintained at 5 percent, and the gas space velocity is 2000 percent-1Treating for 10 hours; then the temperature of the catalyst bed layer is raised to 500 ℃, the oxygen content is raised to 8 percent, the chlorinating agent content is maintained at 5 percent, and the gas space velocity is 2000-1Treating for 10 hours; then the temperature of the catalyst bed layer is raised to 550 ℃, the oxygen content is raised to 15 percent, the chlorinating agent content is maintained at 5 percent, and the gas space velocity is 2000-1Treating for 10 hours; and finally, blowing the catalyst bed layer by using nitrogen, and controlling the oxygen content to be lower than 0.2 percent and the chlorinating agent content to be lower than 0.1 percent.
After the carbon burning and chlorination are finished, the reduction link is carried out. Adjusting the temperature of the catalyst bed layer to 400 ℃, introducing reducing gas, wherein the hydrogen content is controlled to be 3 percent, and the gas space velocity is 2000-1Treating for 3 hours; then the temperature of the catalyst bed layer is raised to 450 ℃, the hydrogen content is controlled to be 10 percent, and the gas space velocity is 2000-1Treating for 3 hours; then the temperature of the catalyst bed layer is raised to 480 ℃, the hydrogen content is controlled to 40 percent, and the gas space velocity is 2000-1Treating for 3 hours; final stabilization of the catalystThe bed is at 480 deg.C, the hydrogen content is controlled at 80%, and the gas space velocity is 2000-1And treating for 3 hours. Then nitrogen is introduced to replace the hydrogen in the system, and the concentration is reduced to be below 0.5 percent. By this time, catalyst regeneration is complete.
Example 2
After the catalyst for preparing propylene by dehydrogenation of aluminum oxide-supported platinum tin propane is deactivated (the conversion rate of propane is lower than 15% or the selectivity of propylene is lower than 85%), the catalyst is regenerated. Reducing the temperature of the catalyst bed layer to 400 ℃, introducing regeneration treatment gas, wherein the oxygen content is 0.5 percent, the content of the chlorinating agent dichloromethane is 5 percent, and the gas space velocity is 4000-1Treating for 10 hours; then the temperature of the catalyst bed layer is raised to 450 ℃, the oxygen content is raised to 3 percent, the chlorinating agent content is maintained at 5 percent, and the gas space velocity is 4000-1Treating for 10 hours; then the temperature of the catalyst bed layer is raised to 500 ℃, the oxygen content is raised to 8 percent, the chlorinating agent content is maintained at 5 percent, and the gas space velocity is 4000-1Treating for 10 hours; then the temperature of the catalyst bed layer is raised to 550 ℃, the oxygen content is raised to 15 percent, the chlorinating agent content is maintained at 5 percent, and the gas space velocity is 4000-1Treating for 10 hours; and finally, blowing the catalyst bed layer by using nitrogen, and controlling the oxygen content to be lower than 0.2 percent and the chlorinating agent content to be lower than 0.1 percent.
After the carbon burning and chlorination are finished, the reduction link is carried out. Adjusting the temperature of the catalyst bed layer to 400 ℃, introducing reducing gas, wherein the hydrogen content is controlled to be 3 percent, and the gas space velocity is 4000-1Treating for 3 hours; then the temperature of the catalyst bed layer is raised to 450 ℃, the hydrogen content is controlled to be 10 percent, and the gas space velocity is 4000-1Treating for 3 hours; then the temperature of the catalyst bed layer is raised to 480 ℃, the hydrogen content is controlled to 40 percent, and the gas space velocity is 4000-1Treating for 3 hours; finally, the stable catalyst bed is controlled at 480 ℃, the hydrogen content is controlled at 80 percent, and the gas space velocity is 4000-1And treating for 3 hours. Then nitrogen is introduced to replace the hydrogen in the system, and the concentration is reduced to be below 0.5 percent. By this time, catalyst regeneration is complete.
Example 3
After the catalyst for preparing propylene by dehydrogenation of aluminium oxide loaded platinum tin propane is deactivated (propane)Alkane conversion less than 15% or propylene selectivity less than 85%), and the catalyst is regenerated. The temperature of the catalyst bed is reduced to 450 ℃, regeneration treatment gas is introduced, wherein the oxygen content is 0.5 percent, the content of the chlorinating agents, namely, chloromethane and trichloromethane is 5 percent, and the gas space velocity is 3000-1Treating for 10 hours; then the temperature of the catalyst bed layer is raised to 500 ℃, the oxygen content is raised to 3 percent, the chlorinating agent content is maintained at 5 percent, and the gas space velocity is 3000-1Treating for 10 hours; then the temperature of the catalyst bed layer is raised to 550 ℃, the oxygen content is raised to 8 percent, the chlorinating agent content is maintained at 5 percent, and the gas space velocity is 3000-1Treating for 10 hours; then the temperature of the catalyst bed layer is raised to 600 ℃, the oxygen content is raised to 15 percent, the chlorinating agent content is maintained at 5 percent, and the gas space velocity is 3000-1Treating for 10 hours; and finally, blowing the catalyst bed layer by using nitrogen, and controlling the oxygen content to be lower than 0.2 percent and the chlorinating agent content to be lower than 0.1 percent.
After the carbon burning and chlorination are finished, the reduction link is carried out. The catalyst bed temperature was adjusted to 450 ℃. Introducing reducing gas, wherein the hydrogen content is controlled at 3%, and the gas space velocity is 3000-1Treating for 3 hours; then the temperature of the catalyst bed layer is raised to 480 ℃, the hydrogen content is controlled at 10 percent, and the gas space velocity is 3000-1Treating for 3 hours; then the temperature of the catalyst bed layer is raised to 500 ℃, the hydrogen content is controlled to be 40 percent, and the gas space velocity is 3000-1Treating for 3 hours; finally, the catalyst bed is stabilized at 500 ℃, the hydrogen content is controlled at 80 percent, and the gas space velocity is 3000-1And treating for 3 hours. Then nitrogen is introduced to replace the hydrogen in the system, and the concentration is reduced to be below 0.5 percent. By this time, catalyst regeneration is complete.
Example 4
After the catalyst for preparing propylene by dehydrogenation of aluminum oxide-supported platinum tin propane is deactivated (the conversion rate of propane is lower than 15% or the selectivity of propylene is lower than 85%), the catalyst is regenerated. The temperature of the catalyst bed is reduced to 450 ℃, regeneration treatment gas is introduced, wherein the oxygen content is 1 percent, the dichloroethane content is 8 percent, and the gas space velocity is 3000-1Treating for 15 hours; then the temperature of the catalyst bed layer is increased to 500 ℃, and the oxygen content is increased to 3Percent, the content of the chlorinating agent is maintained at 8 percent, and the gas space velocity is 3000 percent-1Treating for 15 hours; then the temperature of the catalyst bed layer is raised to 550 ℃, the oxygen content is raised to 10 percent, the chlorinating agent content is maintained at 8 percent, and the gas space velocity is 3000-1Treating for 15 hours; then the temperature of the catalyst bed layer is raised to 600 ℃, the oxygen content is raised to 15 percent, the chlorinating agent content is maintained at 8 percent, and the gas space velocity is 3000-1Treating for 15 hours; and finally, blowing the catalyst bed layer by using nitrogen, and controlling the oxygen content to be lower than 0.2 percent and the chlorinating agent content to be lower than 0.1 percent.
After the carbon burning and chlorination are finished, the reduction link is carried out. The catalyst bed temperature was adjusted to 450 ℃. Introducing reducing gas, wherein the hydrogen content is controlled at 3%, and the gas space velocity is 3000-1Treating for 5 hours; then the temperature of the catalyst bed layer is raised to 480 ℃, the hydrogen content is controlled at 10 percent, and the gas space velocity is 3000-1Treating for 5 hours; then the temperature of the catalyst bed layer is raised to 500 ℃, the hydrogen content is controlled to be 40 percent, and the gas space velocity is 3000-1Treating for 5 hours; finally, the catalyst bed is stabilized at 500 ℃, the hydrogen content is controlled at 100 percent, and the gas space velocity is 3000-1And treating for 5 hours. Then nitrogen is introduced to replace the hydrogen in the system, and the concentration is reduced to be below 0.5 percent. By this time, catalyst regeneration is complete.
Comparative example 1
In this comparative example, only carbon burning was carried out without chlorination, and the regeneration gas included only air and nitrogen.
After the catalyst for preparing propylene by dehydrogenation of aluminum oxide-supported platinum tin propane is deactivated (the conversion rate of propane is lower than 15% or the selectivity of propylene is lower than 85%), the catalyst is regenerated. Firstly, carrying out carbon burning treatment, reducing the temperature of a catalyst bed layer to 450 ℃, and introducing mixed gas of air and nitrogen. At the beginning, the oxygen content in the mixed gas is 0.5 percent, and the gas space velocity is 3000-1Treating for 10 hours; then the temperature of the catalyst bed layer is raised to 500 ℃, the oxygen content is raised to 3 percent, and the gas space velocity is 3000-1Treating for 10 hours; then the temperature of the catalyst bed layer is raised to 550 ℃, the oxygen content is raised to 8 percent, and the gas space velocity is 3000-1Treating for 10 hours; then the temperature of the catalyst bed layerRaising the temperature to 600 ℃, increasing the oxygen content to 15 percent and ensuring the gas space velocity to be 3000-1Treating for 10 hours; finally, nitrogen is used for blowing the catalyst bed layer, and the oxygen content is controlled to be lower than 0.2 percent.
And after the carbon burning is finished, entering a reduction link. The catalyst bed temperature was adjusted to 450 ℃. Introducing reducing gas, wherein the hydrogen content is controlled at 3%, and the gas space velocity is 3000-1Treating for 3 hours; then the temperature of the catalyst bed layer is raised to 480 ℃, the hydrogen content is controlled at 10 percent, and the gas space velocity is 3000-1Treating for 3 hours; then the temperature of the catalyst bed layer is raised to 500 ℃, the hydrogen content is controlled to be 40 percent, and the gas space velocity is 3000-1Treating for 3 hours; finally, the catalyst bed is stabilized at 500 ℃, the hydrogen content is controlled at 80 percent, and the gas space velocity is 3000-1And treating for 3 hours. Then nitrogen is introduced to replace the hydrogen in the system, and the concentration is reduced to be below 0.5 percent. By this time, catalyst regeneration is complete.
Comparative example 2
This comparative example was conducted separately for char burning and chlorination,
after the catalyst for preparing propylene by dehydrogenation of aluminum oxide-supported platinum tin propane is deactivated (the conversion rate of propane is lower than 15% or the selectivity of propylene is lower than 85%), the catalyst is regenerated. Firstly, carrying out carbon burning treatment, reducing the temperature of a catalyst bed layer to 450 ℃, and introducing mixed gas of air and nitrogen. At the beginning, the oxygen content in the mixed gas is 0.5 percent, and the gas space velocity is 3000-1Treating for 10 hours; then the temperature of the catalyst bed layer is raised to 500 ℃, the oxygen content is raised to 3 percent, and the gas space velocity is 3000-1Treating for 10 hours; then the temperature of the catalyst bed layer is raised to 550 ℃, the oxygen content is raised to 8 percent, and the gas space velocity is 3000-1Treating for 10 hours; then the temperature of the catalyst bed layer is raised to 600 ℃, the oxygen content is raised to 15 percent, and the gas space velocity is 3000-1Treating for 10 hours; finally, nitrogen is used for blowing the catalyst bed layer, and the oxygen content is controlled to be lower than 0.2 percent.
And after the carbon burning is finished, entering a chlorination link. The catalyst bed temperature was adjusted to 500 ℃. Introducing chlorinating agent, namely chloromethane, wherein the content of the chlorinating agent is controlled to be 5 percent, and the gas space velocity is 3000-1And the treatment is carried out for 4 hours. Then, nitrogen gas was introduced to replace the chlorinating agent in the system, thereby reducing the concentration to 0.1% or less.
And after the chlorination is finished, entering a reduction link. The catalyst bed temperature was adjusted to 450 ℃. Introducing reducing gas, wherein the hydrogen content is controlled at 3%, and the gas space velocity is 3000-1Treating for 3 hours; then the temperature of the catalyst bed layer is raised to 480 ℃, the hydrogen content is controlled at 10 percent, and the gas space velocity is 3000-1Treating for 3 hours; then the temperature of the catalyst bed layer is raised to 500 ℃, the hydrogen content is controlled to be 40 percent, and the gas space velocity is 3000-1Treating for 3 hours; finally, the catalyst bed is stabilized at 500 ℃, the hydrogen content is controlled at 80 percent, and the gas space velocity is 3000-1And treating for 3 hours. Then nitrogen is introduced to replace the hydrogen in the system, and the concentration is reduced to be below 0.5 percent. By this time, catalyst regeneration is complete.
Evaluation of catalyst regeneration Performance
The activity evaluation of the catalyst adopts a fixed bed reaction device, the loading of the catalyst is 5g, propane is used as a raw material, hydrogen is used as diluent gas (the proportion is 30 percent), the pressure is controlled to be 0.1MPa, the mass space velocity is 2.0h < -1 >, and the temperature of a catalyst bed layer is controlled to be 600 ℃. Table 1 shows the catalyst activity evaluations of the above-mentioned examples 1 to 4 and comparative examples.
TABLE 1 evaluation table of activity of catalyst for dehydrogenation of aluminum oxide loaded platinum tin propane to propylene
Figure GDA0002360550600000121
Table 1 above shows that, in examples 1 to 4, the catalyst prepared by dehydrogenating platinum-tin-loaded aluminum oxide to produce propylene by the regeneration method of the present invention is regenerated, and the regenerated catalyst has good performance parameters such as propane conversion rate, propylene selectivity, and one-way life, and maintains good catalytic activity. However, if the catalyst is subjected to the carbon burning treatment only according to comparative example 1, or carbon burning is performed first and then chlorination is performed according to the method of comparative example 2, the activity of the regenerated catalyst is remarkably reduced and the service life is also short.
In conclusion, the regeneration method of the aluminum oxide loaded platinum-tin dehydrogenation catalyst can realize good regeneration of the catalyst activity, prolong the service life of the catalyst and improve the running economy of the device.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.

Claims (8)

1. A regeneration method of an aluminum oxide supported platinum tin dehydrogenation catalyst is characterized by comprising the following steps of carbon burning chlorination and reduction:
the carbon burning chlorination is to contact the inactivated catalyst with a regeneration gas for carbon burning and chlorination, and to sweep a catalyst bed layer with nitrogen when the carbon burning chlorination is finished, wherein the volume content of oxygen in the system is controlled to be lower than 0.2%, and the volume content of a chlorinating agent is controlled to be lower than 0.1%; the regeneration gas comprises air, nitrogen and a chlorinating agent;
in the reduction step, the catalyst after carbon burning and chlorination is contacted with a reducing gas for catalyst reduction, and a catalyst bed layer is swept by nitrogen when the reduction is finished, so that the volume content of hydrogen in the system is reduced to be less than 0.5%, wherein the reducing gas is nitrogen and hydrogen;
in the step of carbon burning chlorination, the volume content of oxygen in the regeneration gas is increased from 0.5-1%, the content of a chlorinating agent is 2-8%, and the air speed of the gas is 1000-5000 h-1The method comprises the following specific operations:
1) the temperature of a catalyst bed layer is 400-500 ℃, the volume content of oxygen is 0.5-1%, the volume content of a chlorinating agent is 2-8%, and the air speed of gas is 1000-5000 h-1Treating for 6-18 hours;
2) the temperature of a catalyst bed layer is 450-500 ℃, the volume content of oxygen is 1-5%, the volume content of a chlorinating agent is 2-8%, and the air speed of gas is 1000-5000 h-1Treating for 6-18 hours;
3) the temperature of a catalyst bed layer is 480-550 ℃, the volume content of oxygen is 5-10%, the volume content of a chlorinating agent is 2-8%, and the air speed of gas is 1000-5000h-1Treating for 6-18 hours;
4) the temperature of a catalyst bed layer is 480-600 ℃, the volume content of oxygen is 10-21%, the volume content of a chlorinating agent is 2-8%, and the air speed of gas is 1000-5000 h-1And treating for 6-18 hours.
2. The method for regenerating a platinum-tin alumina-supported dehydrogenation catalyst according to claim 1, wherein the deactivated catalyst is a catalyst for producing propylene by dehydrogenation of platinum-tin alumina-supported propane.
3. The method of claim 1 wherein the chlorinating agent is one or more of methyl chloride, methylene chloride, chloroform, carbon tetrachloride, dichloroethane, trichloroethane, and tetrachloroethane.
4. The method for regenerating a platinum-tin-supported-alumina dehydrogenation catalyst according to claim 1, wherein the volume content of oxygen in the regeneration gas is 0.5 to 21%; the volume content of the chlorinating agent is 0.5-10%.
5. The method for regenerating a platinum-tin-supported-alumina dehydrogenation catalyst according to claim 1, wherein the volume content of hydrogen in the reducing gas is 1-100%.
6. The method for regenerating the aluminum oxide-supported platinum-tin dehydrogenation catalyst according to claim 1, wherein the space velocity of the regeneration gas is 500 to 10000h-1(ii) a The space velocity of the reducing gas is 500-10000 h-1。
7. The method for regenerating a platinum-tin-supported-alumina dehydrogenation catalyst according to claim 1, wherein the catalyst bed temperature in the carbon-burning chlorination step is 400 to 600 ℃, and the treatment time is 24 to 72 hours; in the reduction step, the temperature of a catalyst bed layer is 400-520 ℃, and the treatment time is 4-24 hours.
8. The method for regenerating the aluminum oxide-supported platinum-tin dehydrogenation catalyst as claimed in claim 1, wherein in the reduction step, the volume content of hydrogen in the reduction gas is increased from 1 to 5%, and the gas space velocity is 1000 to 5000h-1The method comprises the following specific operations:
1) the temperature of a catalyst bed layer is 400-450 ℃, the volume content of hydrogen is 1-5%, and the air speed of gas is 1000-5000 h-1Treating for 1-6 hours;
2) the temperature of a catalyst bed layer is 450-500 ℃, the volume content of hydrogen is 5-20%, and the air speed of gas is 1000-5000 h-1Treating for 1-6 hours;
3) the temperature of a catalyst bed layer is 450-520 ℃, the volume content of hydrogen is 20-50%, and the air speed of gas is 1000-5000 h-1Treating for 1-6 hours;
4) the temperature of a catalyst bed layer is 450-520 ℃, the volume content of hydrogen is 50-100%, and the air speed of gas is 1000-5000 h-1And treating for 1-6 hours.
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