Low-carbon alkane dehydrogenation method

Abstract

The invention relates to the technical field of petrochemical engineering, in particular to a light alkane dehydrogenation method. The method comprises the following steps: a low-carbon alkane raw material containing a vulcanizing agent is contacted with a catalyst for a reaction, the contact comprises first contact and second contact, and the difference value between the temperature of the second contact and the temperature of the first contact is 100-300 DEG C. According to the method, the pretreatment process, namely the first contact treatment process, is provided, the temperature difference between the first contact treatment process and subsequent contact is controlled, carbon deposition generated in the reaction process can be effectively reduced, the dehydrogenation efficiency of low-carbon alkane such as propane in a single cycle is improved, meanwhile, temperature distribution and heat transfer efficiency in the reactor are improved, and the yield is increased. The temperature of a catalyst bed layer is prevented from drastically fluctuating in the reaction process, the production stability is improved, the service life of the catalyst is prolonged, and higher economic value is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of petrochemical engineering, and in particular to a method for dehydrogenating low-carbon alkanes. Background Art

[0002] The propane dehydrogenation process has developed rapidly in my country in recent years. However, the process is carried out at high temperatures, and the dehydrogenation products are prone to polymerization and carbon deposits. The carbon deposits will shield the active sites of the catalyst, resulting in a decrease in reaction activity and the need for catalyst regeneration.

[0003] In recent years, research on chromium-based propane dehydrogenation has focused on catalyst development or fluidized bed process development.

[0004] CN115430457A discloses a single-layer dispersed catalyst for producing propylene by dehydrogenation of propane with low Cr loading and a preparation method thereof, which reduces the amount of chromium used and is beneficial to environmental protection and human health.

[0005] CN112403458A discloses a double-active-center propane dehydrogenation catalyst and its preparation method and application, which reduces the chromium content and uses biomass carbon or activated carbon or mesoporous carbon or carbon nanotubes to improve the catalytic activity.

[0006] CN115055178A discloses a chromium-based dehydrogenation catalyst for low-carbon alkanes in a fluidized bed. It uses metal elements such as alkaline earth metals to adjust the electrical properties of the carrier surface to control the existence state of the active centers of the catalyst, while generating a spinel structure to improve the stability, strength and abrasion of the catalyst.

[0007] Existing research on improving the fixed bed process is not sufficient, and there is still research value on how to improve the process to improve the propane dehydrogenation efficiency. Summary of the invention

[0008] The purpose of the present invention is to overcome the problem of low carbon alkane dehydrogenation efficiency in the prior art, such as fixed bed low carbon alkane dehydrogenation technology, and to provide a method for low carbon alkane dehydrogenation, which has the characteristics of extending production time and improving dehydrogenation efficiency.

[0009] In order to achieve the above-mentioned purpose, the present invention provides a method for dehydrogenating light alkanes, which comprises contacting a light alkane feedstock containing a sulfiding agent with a catalyst for reaction, wherein the contact comprises first contacting and then second contacting, and the difference between the temperature of the second contact and the temperature of the first contact is 100-300°C.

[0010] The method of the present invention proposes a pretreatment process, i.e., a first contact treatment process, and controls the temperature difference between the first contact treatment process and the subsequent contact process, which can effectively reduce carbon deposits generated by the reaction during the reaction, improve the dehydrogenation efficiency of low-carbon alkanes such as propane in a single cycle, and at the same time improve the temperature distribution and heat transfer efficiency in the reactor, avoid drastic fluctuations in the catalyst bed temperature during the reaction, improve production stability and catalyst life, and have higher economic value.

[0011] The present invention preferably introduces component A and component B into the catalyst, thereby greatly improving the heat transfer efficiency of the reaction. In the dehydrogenation reaction stage, the heat absorption of the catalyst bed for the dehydrogenation of low-carbon alkanes such as propane is reduced, the temperature drop is reduced, and the catalytic efficiency is improved. DETAILED DESCRIPTION

[0012] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0013] The present invention provides a method for dehydrogenating low-carbon alkanes, which comprises contacting a low-carbon alkanes raw material containing a sulfiding agent with a catalyst for reaction, wherein the contacting comprises first contacting and then second contacting, and the difference between the temperature of the second contacting and the temperature of the first contacting is 100-300° C. For example, the difference between the temperature of the second contacting and the temperature of the first contacting can be 100° C., 120° C., 150° C., 200° C., 250° C., 280° C., or 300° C.

[0014] The method of the present invention proposes a pretreatment process, i.e., a first contact treatment process, and controls the temperature difference between the first contact treatment process and the subsequent contact process, which can effectively reduce carbon deposits generated by the reaction during the reaction, improve the propane dehydrogenation efficiency of a single cycle, and at the same time improve the temperature distribution and heat transfer efficiency in the reactor, avoid drastic fluctuations in the catalyst bed temperature during the reaction, improve production stability and catalyst life, and have higher economic value.

[0015] According to a particularly preferred embodiment of the present invention, the difference between the second contact temperature and the first contact temperature is 150-250° C. By adopting the above preferred solution, the dehydrogenation efficiency of the reaction can be further improved, and the production stability and catalyst life can be improved.

[0016] In the present invention, as long as the purpose of the present invention can be achieved, the conditions for the first contacting can be conventionally selected in the art.

[0017] According to a preferred embodiment of the present invention, the conditions for the first contact include: a temperature of 350-450°C, preferably 375-425°C.

[0018] According to a preferred embodiment of the present invention, the conditions for the first contact include: a pressure of 80-150 kPa, preferably 100-125 kPa.

[0019] According to a preferred embodiment of the present invention, the conditions for the first contact include: a time of 24-480 hours, preferably 48-240 hours.

[0020] According to a preferred embodiment of the present invention, the conditions for the first contact include: the mass space velocity of the low carbon alkane feedstock containing the sulfiding agent is 0.2-0.7h -1 .

[0021] The aforementioned preferred first contact conditions can further improve the temperature distribution in the bed and the heat transfer efficiency of the propane dehydrogenation reaction. Meanwhile, the introduction of sulfide can inhibit the occurrence of side reactions and further improve the reaction efficiency.

[0022] In the present invention, as long as the purpose of the present invention can be achieved, the conditions for the second contacting can be conventionally selected in the art.

[0023] According to a preferred embodiment of the present invention, the conditions for the second contact include: a temperature of 580-630°C, preferably 590-620°C.

[0024] According to a preferred embodiment of the present invention, the conditions for the second contact include: a pressure of 30-70 kPa, preferably 45-55 kPa.

[0025] According to a preferred embodiment of the present invention, the conditions for the second contact include: a time of 7-15 min, preferably 9-13 min.

[0026] According to a preferred embodiment of the present invention, the conditions for the second contact include: the mass space velocity of the low carbon alkane feedstock containing the sulfiding agent is 0.2-0.7h -1 .

[0027] The use of the aforementioned preferred second contact conditions can further improve the catalytic effect of the propane dehydrogenation catalyst, reduce the reaction shifting toward side reactions, and allow the catalyst to operate in a high activity range.

[0028] According to a preferred embodiment of the present invention, the method includes sequentially performing a first treatment, a second treatment, and a third treatment on the catalyst after the contact reaction is completed, and then performing the next contact reaction, wherein the first treatment is performed under an inert atmosphere, the second treatment is performed under an oxygen-containing atmosphere, and the third treatment is performed under a reducing atmosphere. The aforementioned preferred embodiment can further enable the catalyst to maintain high activity for a long time.

[0029] The inert atmosphere is selected from one or more of nitrogen, argon, helium, carbon dioxide and water vapor.

[0030] The oxygen-containing atmosphere is selected from an atmosphere containing oxygen with a volume fraction of 5% to 30%, and the remaining gas can be one or more of nitrogen, argon, helium, carbon dioxide, and water vapor.

[0031] The reducing atmosphere is selected from one or more of hydrogen, carbon monoxide, alkanes and alkenes.

[0032] In the present invention, as long as the purpose of the present invention can be achieved, the conditions of the first treatment can be conventionally selected in the art. According to a preferred embodiment of the present invention, the conditions of the first treatment include: a temperature of 200-400° C. and a time of 1-5 min. The aforementioned preferred embodiment can further improve the treatment efficiency.

[0033] In order to further improve the treatment efficiency, according to a preferred embodiment of the present invention, the conditions of the first treatment include: a temperature of 230-350° C. and a time of 2-3 min.

[0034] In the present invention, as long as the purpose of the present invention can be achieved, the conditions of the second treatment can be conventionally selected in the art. According to a preferred embodiment of the present invention, the conditions of the second treatment include: a temperature of 650-750°C, a pressure of 70-150 kPa, and a time of 7-15 min. The aforementioned preferred embodiment can further ensure the catalyst treatment time at high temperature and reduce the catalyst life loss.

[0035] In order to further improve the treatment efficiency, according to a preferred embodiment of the present invention, the conditions of the second treatment include: temperature of 680-720° C., pressure of 90-130 kPa, and time of 9-13 min.

[0036] In the present invention, as long as the purpose of the present invention can be achieved, the conditions of the third treatment can be conventionally selected in the art. According to a preferred embodiment of the present invention, the conditions of the third treatment include: a temperature of 400-600° C. and a time of 1-5 min. The aforementioned preferred embodiment can further improve the propane dehydrogenation activity of the catalyst, while replacing the oxygen-containing gas to ensure production safety.

[0037] In order to further improve the replacement efficiency and catalyst activation effect, according to a preferred embodiment of the present invention, the conditions of the third treatment include: temperature of 500-580° C. and time of 2-3 min.

[0038] According to a preferred embodiment of the present invention, the volume fraction of the sulfiding agent in the low carbon alkane feedstock containing the sulfiding agent is 10-100 ppm, preferably 15-80 ppm. The above preferred embodiment can further improve the inhibitory effect of the pretreatment on the catalyst side reaction.

[0039] In the present invention, the types of the sulfiding agent can be selected from a wide range. According to a preferred embodiment of the present invention, the sulfiding agent is selected from at least one of hydrogen sulfide, carbonyl sulfide, dimethyl disulfide, diethyl disulfide, methyl mercaptan, and ethyl mercaptan, preferably dimethyl disulfide. The above preferred embodiment can further improve the inhibition efficiency.

[0040] In the present invention, the types of low carbon alkanes can be selected from a wide range. According to a preferred embodiment of the present invention, the low carbon alkanes are one or more C3-C5 alkanes, preferably propane. The above preferred embodiment can further improve the dehydrogenation effect of the catalyst.

[0041] According to a preferred embodiment of the present invention, the method includes recycling the unreacted light alkane back to the light alkane feedstock containing the sulfiding agent after the contact reaction is completed. The aforementioned preferred embodiment can further improve the production efficiency of the reaction and reduce the loss of raw materials.

[0042] According to a preferred embodiment of the present invention, the method is carried out in an adiabatic reactor and / or an isothermal reactor, preferably in an adiabatic reactor.

[0043] According to a preferred embodiment of the present invention, the method comprises: contacting a low-carbon alkane feedstock containing a sulfiding agent with a catalyst loaded in an adiabatic reactor for reaction, collecting tail gas containing unreacted low-carbon alkanes for refining and separation to obtain low-carbon alkanes at least once, recycling the low-carbon alkanes back to the low-carbon alkane feedstock containing a sulfiding agent, and contacting and reacting with a catalyst that has been sequentially treated with a first treatment, a second treatment, and a third treatment, preferably repeating the process 3-20 times. The aforementioned preferred embodiment can further improve the efficiency of raw material recycling, reduce raw material loss, and improve production efficiency.

[0044] According to a preferred embodiment of the present invention, the catalyst comprises a dehydrogenation catalyst and an energy storage material, wherein the energy storage material comprises component A and component B, component A comprises a first carrier and an auxiliary component loaded on the first carrier, the auxiliary component comprises at least one of Group IB elements, Group IIB elements, and Group VB elements, and optionally at least one of Group IA elements, Group IIA elements, and Group VIII elements, and component B comprises silicon and / or aluminum materials.

[0045] In the present invention, as long as the purpose of the present invention can be achieved, there is no special requirement for the volume ratio of the dehydrogenation catalyst, component B and component A in the catalyst. According to a preferred embodiment of the present invention, the volume ratio of the dehydrogenation catalyst, component B and component A in the catalyst is 1:0.2-1.2:0.04-0.80, preferably 1:0.4-1:0.2-0.50. The above preferred embodiment can further improve the temperature distribution in the reactor, ensure that the catalyst operates in the high activity range, and extend the service life of the catalyst.

[0046] According to a preferred embodiment of the present invention, the dehydrogenation catalyst comprises a second carrier and an active component loaded on the second carrier, wherein the active component contains at least one of Group IA elements, Group IIA elements, Group IIIA elements, Group IVB elements, Group VIB elements and Group VIII elements, and preferably the active component contains at least one of Group IA elements, Group IVB elements and Group VIB elements.

[0047] According to a preferred embodiment of the present invention, the loading amount of the active component in the dehydrogenation catalyst is 0.1-30%, preferably 0.5-25%. The above preferred embodiment can further improve the catalytic activity of the catalyst.

[0048] In the dehydrogenation catalyst, the second carrier can be selected from a wide range of types. According to a preferred embodiment of the present invention, the second carrier in the dehydrogenation catalyst is selected from at least one of molecular sieves, alumina, silicon oxide and activated carbon. The aforementioned preferred embodiment can further improve the physical properties of the catalyst, such as attrition rate and strength, and extend the service life of the catalyst.

[0049] In the dehydrogenation catalyst, a wide range of Group IA elements can be selected. According to a preferred embodiment of the present invention, the Group IA element is selected from sodium and / or potassium, preferably sodium.

[0050] In the dehydrogenation catalyst, a wide range of Group IIA elements can be selected. According to a preferred embodiment of the present invention, the Group IIA element is selected from magnesium and / or calcium, preferably calcium.

[0051] In the dehydrogenation catalyst, the Group IIIA elements can be selected from a wide range of options. According to a preferred embodiment of the present invention, the Group IIIA elements are selected from boron and / or gallium, preferably gallium.

[0052] In the dehydrogenation catalyst, a wide range of Group IVB elements can be selected. According to a preferred embodiment of the present invention, the Group IVB element is selected from titanium and / or zirconium, preferably zirconium.

[0053] In the dehydrogenation catalyst, the types of Group IVB elements can be selected from a wide range. According to a preferred embodiment of the present invention, the Group VIB element is selected from at least one of chromium, molybdenum and tungsten, preferably chromium.

[0054] In the dehydrogenation catalyst, a wide range of Group VIII elements can be selected. According to a preferred embodiment of the present invention, the Group VIII element is selected from at least one of iron, cobalt and nickel, preferably cobalt.

[0055] According to a preferred embodiment of the present invention, the active component in the dehydrogenation catalyst is at least one of the elements of Group VIB. The above preferred embodiment can further improve the catalytic efficiency of the dehydrogenation of light alkanes.

[0056] In the present invention, the types of silicon / aluminum materials in component B can be selected from a wide range. According to a preferred embodiment of the present invention, the silicon / aluminum material in component B is selected from at least one of aluminum oxide, silicon oxide, calcium silicate, calcium aluminate and silicon carbide, preferably aluminum oxide. The aforementioned preferred embodiment can further improve the physical properties of the material, making it have a long service life, while improving the heat dispersion ability and maintaining uniform temperature distribution of the catalyst bed.

[0057] According to a preferred embodiment of the present invention, the loading amount of the auxiliary component in component A is 0.1-15%, preferably 1.0-10%. The aforementioned preferred embodiment can further improve the ability and rate of the catalyst to store and release heat, ensure that the catalyst bed temperature fluctuates within a narrow range, and improve production stability.

[0058] In component A, the type of the first carrier in component A can be selected from a wide range. According to a preferred embodiment of the present invention, the first carrier in component A is selected from at least one of aluminum oxide, silicon oxide, calcium silicate, calcium aluminate and silicon carbide, preferably calcium aluminate. The aforementioned preferred embodiment can further improve the physical properties of the material, making it have a long service life, while improving the heat dispersion ability and maintaining uniform temperature distribution of the catalyst bed.

[0059] According to a preferred embodiment of the present invention, the Group IA element is selected from at least one of lithium, sodium and potassium, preferably sodium.

[0060] According to a preferred embodiment of the present invention, the Group IIA element is selected from magnesium and / or calcium, preferably calcium.

[0061] According to a preferred embodiment of the present invention, the Group IB element is selected from copper and / or silver, preferably copper.

[0062] According to a preferred embodiment of the present invention, the Group IIB element is selected from zinc.

[0063] According to a preferred embodiment of the present invention, the Group VB element is selected from vanadium and / or niobium.

[0064] According to a preferred embodiment of the present invention, the Group VIII element is selected from at least one of iron, cobalt and nickel, preferably nickel.

[0065] According to a preferred embodiment of the present invention, the active component in component A is a Group IB element, and optionally one or two of a Group IIA element and a Group VIII element. By adopting the aforementioned preferred embodiment, the heat transfer efficiency of component A in the whole production process can be further improved, the catalyst bed temperature can be kept fluctuating in a narrow range, the production efficiency can be improved, and the service life of the catalyst can be extended.

[0066] The present invention will be described in detail below through examples. In the following examples, the conversion rate and selectivity are calculated according to the following formula; the raw materials are all commercially available products.

[0067]

[0068]

[0069] Example 1

[0070] In the adiabatic reactor, the catalyst is loaded in a volume ratio of 1:0.5:0.1 among the dehydrogenation catalyst, component B and component A. The catalyst composition is that the dehydrogenation catalyst is 25% chromium oxide, an alumina carrier, component B is alumina, and component A is 10% copper oxide, a calcium aluminate carrier.

[0071] After preheating propane gas containing 15 ppm of dimethyl disulfide to 375°C, the gas was heated at a space velocity of 0.7 h -1 , and contact with the loaded catalyst for 48 hours at a pressure of 100 kPa. After the sulfur content at the outlet stabilizes, the temperature is raised to 590°C for the first cycle, at a space velocity of 0.7 h -1 , the pressure was 55 kPa and the loaded catalyst was contacted for 9 minutes to obtain a conversion rate of 1 and a selectivity of 1. After 230°C water vapor was introduced into the reactor for 2 minutes, 680°C, 90 kPa air was introduced into the reactor for 13 minutes, and 500°C hydrogen was introduced into the reactor for 2 minutes. The first cycle process was repeated 10 times to obtain a conversion rate of 2 and a selectivity of 2. The conversion rates 1, 2, and selectivities 1, 2 are shown in Table 1.

[0072] Example 2

[0073] In the adiabatic reactor, the catalyst is loaded in a volume ratio of 1:0.5:0.1 among the dehydrogenation catalyst, component B and component A. The catalyst composition is that the dehydrogenation catalyst is 25% chromium oxide, an alumina carrier, component B is alumina, and component A is 10% copper oxide, a calcium aluminate carrier.

[0074] After preheating propane gas containing 50 ppm of dimethyl disulfide to 400 °C, the gas was heated at a space velocity of 0.7 h -1 The pressure is 115 kPa and the loaded catalyst is contacted for 120 hours. After the sulfur content at the outlet is stable, the temperature is raised to 600 ° C and the first cycle is carried out at a space velocity of 0.2 h -1 , the pressure was 50 kPa and the loaded catalyst was contacted for 11 minutes to obtain a conversion rate of 1 and a selectivity of 1. After 290°C water vapor was introduced into the reactor for 2.5 minutes, 700°C, 110 kPa air was introduced into the reactor for 11 minutes, and 540°C hydrogen was introduced into the reactor for 2.5 minutes. The first cycle process was repeated 10 times to obtain a conversion rate of 2 and a selectivity of 2. Conversion rates 1, 2, and selectivities 1, 2 are shown in Table 1.

[0075] Example 3

[0076] In the adiabatic reactor, the catalyst is loaded in a volume ratio of 1:0.5:0.1 among the dehydrogenation catalyst, component B and component A. The catalyst composition is that the dehydrogenation catalyst is 25% chromium oxide, an alumina carrier, component B is alumina, and component A is 10% copper oxide, a calcium aluminate carrier.

[0077] After preheating propane gas containing 80 ppm of dimethyl disulfide to 425°C, the gas was heated at a space velocity of 0.7 h -1 The pressure is 125 kPa and the loaded catalyst is contacted for 240 hours. After the sulfur content at the outlet is stable, the temperature is raised to 620 ° C and the first cycle is carried out at a space velocity of 0.7 h -1 , the pressure was 45 kPa and the loaded catalyst was contacted for 13 minutes to obtain a conversion rate of 1 and a selectivity of 1. After 350°C steam was introduced into the reactor for 3 minutes, 720°C, 130 kPa air was introduced into the reactor for reaction for 13 minutes, and 580°C hydrogen was introduced into the reactor for reaction for 3 minutes. The first cycle process was cycled 10 times to obtain a conversion rate of 2 and a selectivity of 2. Conversion rates 1, 2, selectivities 1, 2 are shown in Table 1.

[0078] Example 4

[0079] The method of Example 1 was followed, except that the volume ratio of the catalyst, component B, and component A was 1:0.1:1. The results are shown in Table 1.

[0080] Example 5

[0081] The method of Example 1 was followed, except that the chromium oxide loading of the catalyst was 35%. The results are shown in Table 1.

[0082] Example 6

[0083] The method of Example 1 was followed, except that the temperature of the first contact was 490° C. (propane gas containing 15 ppm of dimethyl disulfide was preheated to 490° C.). The results are shown in Table 1.

[0084] Example 7

[0085] The method of Example 1 was followed, except that the first, second and third treatments were not performed. The results are shown in Table 1.

[0086] Example 8

[0087] The method of Example 1 was followed, except that the content of dimethyl disulfide was 5 ppm. The results are shown in Table 1.

[0088] Example 9

[0089] The method of Example 1 was followed, except that the first and third processing orders were exchanged. The results are shown in Table 1.

[0090] Comparative Example 1

[0091] The step of "preheating propane gas containing 50 ppm of dimethyl disulfide to 400°C and heating at a space velocity of 0.7 h -1 The catalyst was contacted with the loaded catalyst under the condition of 115 kPa for 120 hours. After the sulfur content at the outlet stabilized, the propane gas containing 50 ppm of dimethyl disulfide was directly heated to 600 °C for the first cycle at a space velocity of 0.2 h -1 , the pressure was 50 kPa and the loaded catalyst was contacted for 11 minutes to obtain a conversion rate of 1 and a selectivity of 1. The rest of the reaction process was the same as in Example 1. The conversion rates of 1 and 2 and the selectivities of 1 and 2 are shown in Table 1.

[0092] Comparative Example 2

[0093] The same as Example 1, except that propane containing no sulfide is used for the reaction, and the rest of the reaction process is the same as Example 1. The conversion rates 1, 2, and the selectivities 1, 2 are shown in Table 1.

[0094] Comparative Example 3

[0095] Same as Example 1, except that the first contact temperature is 590°C (propane gas containing 15 ppm of dimethyl disulfide is preheated to 590°C). The reaction process is the same as Example 1. The conversions 1, 2, and the selectivities 1, 2 are shown in Table 1.

[0096] Example 10

[0097] Same as Example 1, except that component A is not loaded. The reaction process is the same as Example 1. The conversion rates 1, 2, and the selectivities 1, 2 are shown in Table 1.

[0098] Embodiment 11

[0099] The method of Example 1 was followed, except that component B was zirconium oxide. The results are shown in Table 1.

[0100] Example 12

[0101] The method of Example 1 was followed, except that the carrier of component A was zirconium oxide and the auxiliary component was manganese oxide. The results are shown in Table 1.

[0102] Table 1

[0103]

[0104]

[0105] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A method for dehydrogenating light alkanes, characterized in that: The method comprises: contacting a low-carbon alkane raw material containing a sulfiding agent with a catalyst for reaction; The contacting includes first contacting and then second contacting, and the difference between the temperature of the second contacting and the temperature of the first contacting is 100-300°C.

2. The method according to claim 1, wherein: The difference between the second contact temperature and the first contact temperature is 150-250°C; preferably, The conditions of the first contact include: The temperature is 350-450°C, preferably 375-425°C; and / or The pressure is 80-150 kPa, preferably 100-125 kPa; and / or The time is 24-480h, preferably 48-240h; and / or The mass space velocity of low carbon alkane feedstock containing sulfiding agent is 0.2-0.7h -1 ; and / or The conditions for the second contact include: The temperature is 580-630°C, preferably 590-620°C; and / or The pressure is 30-70 kPa, preferably 45-55 kPa; and / or The time is 7-15 min, preferably 9-13 min; and / or The mass space velocity of low carbon alkane feedstock containing sulfiding agent is 0.2-0.7h -1 .

3. The method according to claim 1 or 2, wherein: The method comprises performing a first treatment, a second treatment, and a third treatment on the catalyst in sequence after the contact reaction is completed, and then performing the next contact reaction, wherein the first treatment is performed under an inert atmosphere, the second treatment is performed under an oxygen-containing atmosphere, and the third treatment is performed under a reducing atmosphere; preferably, The conditions of the first treatment include: The temperature is 200-400°C, preferably 230-350°C; and / or The time is 1-5min, preferably 2-3min; and / or The conditions of the second treatment include: The temperature is 650-750°C, preferably 680-720°C; and / or The pressure is 70-150 kPa, preferably 90-130 kPa; and / or The time is 7-15 minutes, preferably 9-13 minutes; The conditions of the third process include: The temperature is 400-600°C, preferably 500-580°C; and / or The time is 1-5 min, preferably 2-3 min.

4. The method according to any one of claims 1 to 3, wherein: The volume fraction of the sulfiding agent in the low carbon alkane feedstock containing the sulfiding agent is 10-100 ppm, preferably 15-80 ppm; and / or The sulfiding agent is selected from at least one of hydrogen sulfide, carbonyl sulfide, dimethyl disulfide, diethyl disulfide, methyl mercaptan, and ethyl mercaptan, preferably dimethyl disulfide; and / or The low carbon alkane is one or more of C3-C5 alkanes, preferably propane.

5. The preparation method according to any one of claims 1 to 4, wherein: The method comprises recycling the unreacted light alkane back to the light alkane feedstock containing the sulfiding agent after the contact reaction is completed; and / or The process is carried out in an adiabatic reactor and / or an isothermal reactor, preferably an adiabatic reactor.

6. The method according to any one of claims 1 to 5, wherein: The method comprises: The process of contacting a low-carbon alkane feedstock containing a sulfiding agent with a catalyst to react, collecting the tail gas containing unreacted low-carbon alkanes at least once for refining and separation to obtain low-carbon alkanes, recycling the low-carbon alkanes back to the low-carbon alkane feedstock containing a sulfiding agent, and contacting with the catalyst that has been sequentially treated with the first treatment, the second treatment and the third treatment to react; preferably repeated 3-20 times.

7. The method according to any one of claims 1 to 6, wherein: The catalyst comprises a dehydrogenation catalyst and an energy storage material, wherein the energy storage material comprises a component A and a component B, wherein the component A comprises a first carrier and an auxiliary component supported on the first carrier, wherein the auxiliary component comprises at least one of a Group IB element, a Group IIB element, and a Group VB element, and optionally at least one of a Group IA element, a Group IIA element, and a Group VIII element, and the component B comprises silicon and / or aluminum material; Preferably, the volume ratio of the dehydrogenation catalyst, component B and component A in the catalyst is 1:0.2-1.2:0.04-0.80, preferably 1:0.4-1:0.1-0.

60.

8. The method according to any one of claims 7, wherein: The dehydrogenation catalyst comprises a second carrier and an active component supported on the second carrier, wherein the active component contains at least one of Group IA elements, Group IIA elements, Group IIIA elements, Group IVB elements, Group VIB elements and Group VIII elements; Preferably, the active component contains at least one of Group IA elements, Group IVB elements, and Group VIB elements; The loading amount of the active component in the dehydrogenation catalyst is 0.1-30%, preferably 0.5-25%; and / or The second carrier in the dehydrogenation catalyst is selected from at least one of molecular sieves, alumina, silicon oxide and activated carbon; Preferably, in the dehydrogenation catalyst, The Group IA element is selected from sodium and / or potassium, preferably sodium; and / or The Group IIA element is selected from magnesium and / or calcium, preferably calcium; and / or The group IIIA element is selected from boron and / or gallium, preferably gallium; and / or The Group IVB element is selected from titanium and / or zirconium, preferably zirconium; and / or The Group VIB element is at least one selected from chromium, molybdenum and tungsten, preferably chromium; and / or The Group VIII element is at least one selected from iron, cobalt and nickel, preferably cobalt; More preferably, the active component in the dehydrogenation catalyst is at least one element from Group VIB.

9. The method according to claim 7, wherein: The silicon / aluminum material in the component B is selected from at least one of aluminum oxide, silicon oxide, calcium silicate, calcium aluminate and silicon carbide, preferably aluminum oxide.

10. The method according to claim 7, wherein: The loading amount of the auxiliary component in the component A is 0.1-15%, preferably 1.0-10%; and / or The first carrier in the component A is selected from at least one of aluminum oxide, silicon oxide, calcium silicate, calcium aluminate and silicon carbide, preferably calcium aluminate; Preferably, in the component A, The Group IA element is at least one selected from lithium, sodium and potassium, preferably sodium; and / or The Group IIA element is selected from magnesium and / or calcium, preferably calcium; and / or The Group IB element is selected from copper and / or silver, preferably copper; and / or The Group IIB element is selected from zinc; and / or The Group VB element is selected from vanadium and / or niobium; and / or The Group VIII element is at least one selected from iron, cobalt and nickel, preferably nickel; More preferably, the auxiliary component in the component A is a Group IB element, and optionally one or two of a Group IIA element and a Group VIII element.

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