Heat generating auxiliary, its preparation method and application and method for dehydrogenation of alkane

Abstract

This invention relates to the field of alkane dehydrogenation, and discloses a heating aid, its preparation method and application, as well as a method for alkane dehydrogenation reactions. The heating aid of this invention, based on its total amount, comprises the following components: a) 1-10 wt% Cu oxide; b) 0.01-2 wt% Group IVA element oxides; c) 16-22 wt% Ca oxide; d) 66-82 wt% carrier; wherein the heating aid contains Ca3Al. 10 O 18 Crystal phase structure. The exothermic agent described in this invention has a specific composition and a special crystal phase structure. When used in the dehydrogenation reaction of alkane, it helps to make the temperature distribution of the catalyst bed more uniform, improve the conversion rate of raw materials and the selectivity of products, and has high stability.

Description

Technical Field

[0001] This invention relates to the field of alkane dehydrogenation, specifically to a heating aid, its preparation method and application, and a method for alkane dehydrogenation reaction. Background Technology

[0002] Propylene is a crucial basic chemical raw material in the petrochemical and polymer materials fields. It is widely used in the production of chemicals such as polypropylene, acrylonitrile, propylene oxide, isopropanol, and phenol, which are further used in the manufacture of various materials including plastics, rubber, and fibers. Beyond its vital role in industry and the chemical sector, propylene also demonstrates its unique value in art and handicrafts.

[0003] Propane dehydrogenation (PDH) to propylene has become a popular propylene production process in recent years due to its high profitability. It uses propane as a feedstock, dehydrogenating it with a catalyst to produce polymer-grade propylene. Currently, the most widely transferred production processes are Lummus's Catofin process and UOP's Oleflex process, which together account for over 90% of the global market share. In recent years, the Catofin process has seen a gradual increase in market share, mainly due to its advantages such as high alkane conversion rate, good product selectivity, strong feedstock adaptability, and high plant uptime. However, due to the fixed-bed reactor operation mode and the inherently endothermic nature of the dehydrogenation reaction, the bed temperature distribution in the reaction system is uneven, with significant temperature differences. Therefore, it is crucial to fully utilize heat, achieve heat balance, or supplement heat to improve conversion efficiency and reduce energy consumption.

[0004] A common method for heat balance is direct heating of the catalyst bed. For example, CN104072325A discloses a fixed-bed reactor using built-in electric heating tubes to provide heat for the dehydrogenation reaction of low-carbon alkanes, thereby improving reaction performance. This is because reducing the temperature drop in the catalyst bed caused by the strongly endothermic dehydrogenation reaction improves the performance of the low-carbon alkane dehydrogenation reaction and increases the yield of olefins. Some recent patents disclose the use of exothermic promoters as auxiliary agents in the catalyst bed.

[0005] CN112812752A discloses a heat storage material for propane catalytic dehydrogenation to propylene with a specific pore structure and its preparation method. The heat storage material is a CuO-based material supported on Al2O3 with a specific pore size structure. A pore-forming agent is added to modify the pore structure and shape the Al2O3 support material. The pore-forming agent can be one or more of the following: citric acid, oxalic acid, benzoic acid, polyvinyl alcohol, polyvinyl butyral, polymer microspheres, starch, stearic acid, activated carbon, graphite, phenolic resin, and urea. However, abundant pores may reduce catalyst strength and be detrimental to the stability of the heat storage material.

[0006] CN113388376A discloses an alkane dehydrogenation heating aid, its preparation method, and its application. It is mainly prepared from CaO, CuO, and Al2O3, with the weight parts of CaO, CuO, and Al2O3 being 35-90 parts, 10-40 parts, and 5-40 parts, respectively. In this alkane dehydrogenation heating aid, Cu element mainly exists in the form of CaCu2O3 and Ca2CuO3, and the ratio of the number of Ca atoms to the number of Al atoms is ≥6 / 7, which reduces the utilization rate of CuO.

[0007] Therefore, there is an urgent need to develop a heat-generating promoter that can effectively reduce bed temperature drop, thereby improving catalytic performance and stability. Summary of the Invention

[0008] The purpose of this invention is to overcome the problem of high catalyst bed temperature drop in the existing technology of alkane dehydrogenation reaction, and to provide a heat-generating aid, its preparation method and application, as well as a method for alkane dehydrogenation reaction. The heat-generating aid described in this invention has a specific composition and a special crystal phase structure. Its application in alkane dehydrogenation reaction facilitates better coupling of heat and reaction, resulting in a more uniform temperature distribution in the catalyst bed, improved feed conversion rate and product selectivity, and high stability.

[0009] To achieve the above objectives, a first aspect of the present invention provides a heating aid, comprising the following components based on the total amount of the heating aid: a) 1-10 wt% Cu oxide; b) 0.01-2 wt% of Group IVA element oxides; c) 16-22 wt% Ca oxides; d) 66-82 wt% carrier; The heating aid contains Ca3Al 10 O 18 Crystal structure.

[0010] Preferably, the support is Al2O3, and the Ca3Al 10 O 18 The molar ratio of Al2O3 to Al2O3 is 0.1-0.4:1.

[0011] A second aspect of the present invention provides a method for preparing the heating aid described in the first aspect, the method comprising: The carrier is loaded by contacting a Ca source, a Group IVA element source, and a Cu source, followed by drying and calcination to obtain the exothermic agent.

[0012] A third aspect of the present invention provides the application of the exothermic agent described in the first aspect in the dehydrogenation reaction of alkane.

[0013] The fourth aspect of the present invention provides a method for alkane dehydrogenation reaction, wherein the alkane dehydrogenation reaction is carried out in the presence of the exothermic agent and the alkane dehydrogenation catalyst described in the first aspect.

[0014] Through the above technical solution, the present invention has the following beneficial effects: The exothermic agent provided by this invention has a specific composition and a special crystal phase structure. When mixed with a catalyst and used in the alkane dehydrogenation reaction process, it can better couple heat and reaction, release a large amount of heat during the reaction, thereby suppressing the temperature drop during the reaction, making the temperature distribution of the catalyst bed more uniform, improving the conversion rate of raw materials and the selectivity of products, and has high stability. Attached Figure Description

[0015] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the following detailed description to explain the invention, but do not constitute a limitation thereof.

[0016] Figure 1 This is the XRD pattern of the heating aid in Example 1; Figure 2 This is the XRD pattern of the heating accelerator in Comparative Example 1. Detailed Implementation

[0017] The endpoints and any values ​​of the ranges disclosed herein 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 the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0018] The first aspect of this invention provides a heating aid, comprising the following components based on the total amount of the heating aid: a) 1-10 wt% Cu oxide; b) 0.01-2 wt% of Group IVA element oxides; c) 16-22 wt% Ca oxides; d) 66-82 wt% carrier; The heating aid contains Ca3Al 10 O 18 Crystal structure.

[0019] In this invention, the inventors discovered during the research process that using a heat-generating agent with the specific composition and special crystal phase structure, mixed with an alkane dehydrogenation catalyst, in the alkane dehydrogenation reaction process, can better couple heat and reaction, release a large amount of heat during the reaction, thereby suppressing the temperature drop during the reaction, making the temperature distribution of the catalyst bed more uniform, improving the conversion rate of raw materials and the selectivity of products, and having high stability.

[0020] In this invention, the heating aid contains Ca3Al 10 O 18 The crystal structure was confirmed by X-ray diffraction characterization.

[0021] In this invention, preferably, the content of Cu oxide in the heating aid, by mass percentage, can be 1wt%, 2wt%, 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt%, or any value within the range of any two of the above values, preferably 4-9wt%.

[0022] In this invention, preferably, the content of group IVA element oxides in the heating aid, by mass percentage, can be 0.01wt%, 0.1wt%, 0.5wt%, 0.75wt%, 1wt%, 1.25wt%, 1.5wt%, 2wt%, or any value within the range of any two of the above values, preferably 0.5-1.5wt%.

[0023] In this invention, preferably, the content of Ca oxide in the heating aid, by mass percentage, can be 16wt%, 17wt%, 18wt%, 19wt%, 20wt%, 21wt%, 22wt%, or any value within the range of any two of the above values, preferably 17-20wt%.

[0024] In this invention, preferably, the content of the carrier in the heating aid, by mass percentage, can be 66wt%, 68wt%, 70wt%, 72wt%, 74wt%, 76wt%, 78wt%, 80wt%, 82wt%, or any value within the range of any two of the above values, preferably 68-78wt%.

[0025] In this invention, unless otherwise specified, the total amount of Cu oxide, Group IVA element oxides, Ca oxide, and carrier in the heating aid is 100 wt%. In this invention, the content of each component in the heating aid is determined according to the amount of feed.

[0026] In this invention, controlling the content of each component in the heating aid within the aforementioned range is beneficial for better leveraging the synergistic effect between Cu oxide, Group IVA element oxides, and Ca oxide. When mixed with an alkane dehydrogenation catalyst and used in the alkane dehydrogenation reaction, it better couples heat and reaction, resulting in a more uniform temperature distribution in the catalyst bed and improved overall catalyst performance. The preferred range exhibits even superior effects.

[0027] In this invention, the type of support has a wide range of selection; for example, it can be Al2O3 and / or SiO2-Al2O3, preferably Al2O3. In some embodiments of this invention, preferably, the Ca3Al... 10 O 18 The molar ratio of CaAl to Al2O3 is 0.1-0.4:1, for example, it can be 0.1:1, 0.15:1, 0.2:1, 0.25:1, 0.3:1, 0.35:1, 0.4:1, or any value within the range of any two of the above values, preferably 0.15-0.3:1. In this invention, unless otherwise specified, CaAl... 12 O 19 The molar ratio of Al2O3 to Al2O3 was obtained by quantitative analysis of the XRD patterns using the TOPAS software and the Rietveld method based on the least squares principle.

[0028] In this invention, Ca3Al 10 O 18 Controlling the molar ratio of Al2O3 to Al2O3 within the above range is beneficial to improving the exothermic ability of the exothermic additive, releasing more heat, and ensuring good stability, which is beneficial to improving the performance of the catalyst.

[0029] In this invention, the Group IVA elements have the advantage of enhancing the dispersibility of Cu oxide and regulating the interaction between Cu oxide and other components. The types of Group IVA elements used in this invention are not particularly limited. Preferably, the Group IVA elements are selected from at least one of Pb, Ge, and Sn. These preferred Group IVA elements are beneficial for giving the heating aid a superior exothermic capability.

[0030] In this invention, the mass ratio of the Ca oxide to the Group IVA element oxide has a wide range of selection. Preferably, the mass ratio of the Ca oxide to the Group IVA element oxide is 8-40:1. For example, it can be 8:1, 12:1, 15:1, 20:1, 25:1, 30:1, 35:1, 40:1, or any value within the range of any two of the above values. Preferably, it is 12-40:1.

[0031] In this invention, controlling the mass ratio of Ca oxide and Group IVA element oxides within the above-mentioned range is beneficial for Cu oxide, Ca oxide and Group IVA elements to exert a better synergistic effect. When applied to alkane dehydrogenation reaction, it can better couple heat and reaction, regulate the heat balance of reaction, and significantly improve the catalytic performance of the catalyst.

[0032] In this invention, the combination of the Ca oxide, Group IVA element oxides, and Cu oxides with the support is not particularly limited. Preferably, the heating aid contains a support modified with Ca oxide and Group IVA element oxides, and Cu oxides supported on the modified support. More preferably, in this invention, the Al2O3 support is modified with Ca oxide and Group IVA element oxides, so that the modified support has Ca3Al 10 O 18 Crystal phase structure. In this invention, the exothermic agent having the described crystal phase structure is used in the alkane dehydrogenation reaction, which is beneficial for releasing a large amount of heat, making the temperature distribution of the catalyst bed more uniform, improving the overall performance of the catalyst, and increasing the conversion rate of raw materials and the selectivity of products.

[0033] In this invention, preferably, the carrier is a molded carrier. The molded carrier of this invention has high heat transfer efficiency and can prevent the formation of localized hot spots. In this invention, the morphology of the carrier is not particularly limited and can be any molded carrier with various morphologies commonly used in the art. Preferably, the carrier is selected from at least one of a cylinder, a trilobal strip, a tetralobal strip, and a sphere, with a cylinder being the most preferred.

[0034] A second aspect of the present invention provides a method for preparing the heating aid described in the first aspect, the method comprising: The carrier is loaded by contacting a Ca source, a Group IVA element source, and a Cu source, and then dried and calcined to obtain the exothermic agent.

[0035] In this invention, the selection of the Ca source, Group IVA element source, and Cu source is not particularly limited, as long as the prepared heating agent contains the desired Cu oxide, Ca oxide, and IVA element oxide. Preferably, the Cu source, Ca source, and Group IVA element source each independently include at least one of the following: nitrate, sulfate, hydrochloride, acetate, phosphate, and acetylacetone salt of the corresponding element. More preferably, the Cu source is copper nitrate; the Ca source is calcium nitrate; and the Group IVA element source is selected from at least one of germanium chloride, tin chloride, and lead chloride.

[0036] In this invention, the carrier can be commercially available or prepared using existing technology. Preferably, the alumina precursor, binder, and co-solvent are mixed and kneaded, then extruded to obtain the carrier. More preferably, the alumina precursor and binder are mixed, then a medium solvent is added and kneaded, then extruded to obtain the carrier. In this invention, the mixing conditions are not particularly limited; for example, the mixing time is preferably 15-30 minutes. In this invention, the kneading conditions are not particularly limited, as long as it is kneaded into a dough-like state; for example, the kneading time is preferably 15-30 minutes.

[0037] In this invention, the type of alumina precursor is not particularly limited and can be any alumina precursor conventionally used in the art, preferably boehmite. In this invention, the type of binder is not particularly limited and can be any binder conventionally used in the art. Preferably, the binder is selected from at least one of guar gum powder, hydroxypropyl cellulose, starch, and clay. In this invention, the type of co-solvent is not particularly limited and any co-solvent conventionally used in the art can be used. Preferably, the co-solvent is selected from at least one of nitric acid, hydrochloric acid, citric acid, and dichloroacetic acid. In this invention, the amount of binder and co-solvent is not particularly limited, and those skilled in the art can choose according to actual conditions. Preferably, the mass ratio of the alumina precursor to the binder is 1:0.01-0.08. Preferably, the mass ratio of the alumina precursor to the co-solvent is 1:0.01-0.05.

[0038] In this invention, to further improve the effect of the heating aid in the dehydrogenation reaction of alkane, preferably, the method includes: (1) The support, Ca source and IVA element source are brought into first contact, and then dried and calcined to obtain the modified support; (2) The Cu source and the modified support are brought into a second contact, and then dried and calcined to obtain the heating aid.

[0039] In this invention, the method of the first contact is not particularly limited, as long as it enables the formation of Ca3Al in the modified support. 10 O 18 The crystal phase structure is acceptable. Preferably, the first contact is selected from at least one of the following methods: impregnation, precipitation, spraying, and mixing, with impregnation being the preferred method and equal-volume impregnation being more preferred.

[0040] In this invention, the method of the second contact is not particularly limited, as long as it does not affect the performance of the heating agent. Preferably, the second contact is selected from at least one of the methods of impregnation, precipitation, spraying and mixing, preferably impregnation, and more preferably equal volume impregnation.

[0041] In this invention, preferably, the method in step (1) further includes: drying and third calcining the carrier before it comes into first contact with the Ca source and the IVA element source.

[0042] In this invention, the calcination conditions have a wide range of selection, as long as Ca3Al is formed in the modified support. 10 O 18 The crystal phase structure is acceptable. Preferably, the temperature of the third calcination is 1200-1400℃, and the calcination time is 4-24 hours. In this invention, the temperature of the third calcination is controlled within the above range so that Ca3Al is formed after subsequent processing. 10 O 18 Crystal phase structure. The drying method and conditions described in this invention are not particularly limited. Preferably, the drying conditions include: a temperature of 80-150℃, more preferably 110-130℃; and a time of 6-24 hours, more preferably 12-18 hours.

[0043] In this invention, the conditions for the first and second calcinations have a wide range of selection, as long as Ca3Al can be formed in the heating aid. 10 O 18 The crystal structure should not affect the performance of the heating aid. Preferably, the temperature of the first calcination is higher than the temperature of the second calcination. More preferably, the temperature of the third calcination is higher than the temperature of the second calcination, and the temperature of the first calcination is between the temperatures of the third calcination and the second calcination. Even more preferably, the temperature of the first calcination is 900-1200℃, more preferably 1000-1100℃.

[0044] In this invention, the temperature of the second calcination has a wide range of selection, as long as it is lower than the temperature of the first calcination without affecting the performance of the heating aid. Preferably, the temperature of the second calcination is 300-500℃, and more preferably 350-450℃.

[0045] In this invention, setting the temperatures for the first, second, and third calcinations in this manner is beneficial for the formation of Ca3Al in the heating aid. 10 O 18 The crystalline structure allows for better coupling of heat and reaction in the dehydrogenation of alkane, resulting in a more uniform temperature distribution in the catalyst bed, improved feed conversion and product selectivity, and enhanced stability.

[0046] In this invention, the first and second roasting times are not particularly limited. Preferably, the first and second roasting times are each independently 4-24 hours, more preferably 6-12 hours.

[0047] In this invention, the drying method and conditions described in step (1) are not particularly limited, as long as they do not affect the performance of the heating agent. Preferably, the drying conditions described in step (1) include: a temperature of 80-150℃, preferably 110-130℃; and a time of 6-24h, preferably 12-18h.

[0048] In this invention, the drying method and conditions described in step (2) are not particularly limited, as long as they do not affect the performance of the heating agent. Preferably, the drying conditions described in step (2) include: a temperature of 80-150℃, preferably 110-130℃; and a time of 6-24h, preferably 12-18h.

[0049] A third aspect of the present invention provides the application of the heating aid described in the first aspect in the dehydrogenation reaction of alkane, wherein the alkane is preferably a C6 or less alkane, and more preferably propane.

[0050] In this invention, the use of the exothermic agent in the alkane dehydrogenation reaction is beneficial for better coupling of heat and reaction, resulting in a more uniform temperature distribution in the catalyst bed, improved conversion rate of raw materials and selectivity of products, and high stability. The exothermic agent described in this invention is particularly suitable for application in the propane dehydrogenation reaction.

[0051] The fourth aspect of the present invention provides a method for alkane dehydrogenation reaction, wherein the alkane dehydrogenation reaction is carried out in the presence of the exothermic agent described in the first aspect and the alkane dehydrogenation catalyst, wherein the alkane is preferably a C6 or less alkane, and more preferably propane.

[0052] In this invention, the amounts of the heating aid and the propane dehydrogenation catalyst have a wide range of selection. Preferably, the volume ratio of the heating aid to the propane dehydrogenation catalyst is 0.2-1.2:1, for example, it can be 0.2:1, 0.4:1, 0.6:1, 0.8:1, 1:1, 1.2:1, or any value within the range of any two of the above values.

[0053] In this invention, the conditions for the alkane dehydrogenation reaction are not particularly limited and can be various alkane dehydrogenation reaction conditions conventionally used in the art. The conditions for the propane dehydrogenation reaction include: a temperature of 500-650°C, preferably 550-620°C; a pressure of 0.05-0.15 MPa, preferably 0.08-0.12 MPa; and a mass hourly space velocity of 0.5-5 h⁻¹. -1 Preferably 0.5-2h -1 .

[0054] In this invention, the type of alkane dehydrogenation catalyst is not particularly limited, and various alkane dehydrogenation catalysts conventionally used in the art can be used in this invention. Preferably, the alkane dehydrogenation catalyst comprises a support and an active metal component, wherein the active metal is selected from at least one of chromium, potassium, and zirconium, preferably chromium, potassium, and zirconium; the support is selected from at least one of alumina, silicon oxide, zirconium oxide, and silicon carbide, preferably alumina. More preferably, the dehydrogenation catalyst comprises: 0.1-5 wt% K₂O, 1-10 wt% ZrO₂, 5-20 wt% Cr₂O₃, and 70-90 wt% Al₂O₃.

[0055] In this invention, the source of the alkane dehydrogenation catalyst is not particularly limited; it can be commercially available or prepared using existing technologies. Preferably, the preparation method of the alkane dehydrogenation catalyst includes: preparing an impregnation solution containing an active metal, impregnating and contacting it with a support, followed by solid-liquid separation, drying, and calcination.

[0056] In this invention, the conditions for impregnation contact, solid-liquid separation, drying and calcination in the preparation process of the alkane dehydrogenation catalyst can be selected according to existing technology, and will not be elaborated further in this invention.

[0057] In this invention, the heating aid, when mixed with the catalyst, is used in the alkane dehydrogenation reaction process. This process can effectively couple heat and reaction, releasing a large amount of heat during the reaction, suppressing the temperature drop during the reaction, resulting in a more uniform temperature distribution in the catalyst bed, improving the conversion rate of raw materials and the selectivity of products, and enhancing stability.

[0058] The present invention will be described in detail below through embodiments. In the present invention, unless otherwise specified, room temperature refers to 25±5℃.

[0059] The X-ray diffraction characterization tests were performed on a Bruker D8 diffractometer manufactured by Bruker GmbH, Germany, equipped with copper K-type radiation (λ=0.154 nm). The diffractometer was scanned at 40 kV and 40 mA, with a scanning range of 5-80°.

[0060] Among them, CaAl 12 O 19 The molar ratio of Al2O3 to Al2O3 was obtained by quantitative analysis of the XRD patterns using the TOPAS software and the Rietveld method based on the least squares principle.

[0061] Example 1 (1) Weigh 500g of boehmite (calculated as Al2O3), 10g of guar gum powder, and 25g of nitric acid solution (nitric acid concentration of 60wt%). The boehmite and guar gum powder are mixed at room temperature for 25 minutes, then the nitric acid solution is added, and the mixture is stirred and kneaded for another 25 minutes to form a dough. The dough is then extruded into a cylindrical shape. Sample I is dried in an oven at 120℃ for 12 hours and then calcined at 1300℃ for 8 hours to obtain sample II after high-temperature calcination.

[0062] (2) Dissolve 75.80 g of calcium nitrate tetrahydrate and 2.05 g of germanium chloride dihydrate in 14.7 g of water to prepare a solution. Weigh 73.5 g of calcined sample II and place it in the solution for equal volume impregnation. Then dry at 120°C for 16 hours and calcin at 1000°C for 8 hours to obtain sample III. (3) Dissolve 22.78 g of copper nitrate trihydrate in 14.7 g of water to prepare a solution. Place sample III in the solution for an equal volume immersion, then dry at 120 °C for 16 hours and calcine at 350 °C for 8 hours to obtain the heating aid.

[0063] The resulting heating aid contains 7.5 wt% Cu oxide, 18 wt% Ca oxide, 1 wt% element IVA oxide, and 73.5 wt% Al2O3 by mass percentage of oxides.

[0064] Figure 1 This is the XRD pattern of the heating aid from Example 1, from... Figure 1 It can be seen that the carrier composition of the heating aid includes not only Al2O3 but also Ca3Al. 10 O 18 Ca3Al 10 O 18 The molar ratio of Al2O3 to Al2O3 is 0.21:1.

[0065] Example 2 (1) Weigh 500g of boehmite (calculated as Al2O3), 10g of guar gum powder, and 25g of nitric acid solution (nitric acid concentration of 60wt%). The boehmite and guar gum powder are mixed at room temperature for 25 minutes, then the nitric acid solution is added, and the mixture is stirred and kneaded for another 25 minutes to form a dough. The dough is then extruded into a cylindrical shape. Sample I is dried in an oven at 120℃ for 12 hours and then calcined at 1300℃ for 8 hours to obtain sample II after high-temperature calcination.

[0066] (2) Dissolve 71.59 g of calcium nitrate tetrahydrate and 0.86 g of stannous chloride dihydrate in 15.7 g of water to prepare a solution. Weigh 78.5 g of calcined sample II and place it in the solution for equal volume impregnation. Then dry at 120°C for 16 hours and calcin at 1000°C for 8 hours to obtain sample III. (3) Dissolve 12.15 g of copper nitrate trihydrate in 15.7 g of water to prepare a solution. Place sample III in the solution for an equal volume immersion, then dry at 120 °C for 16 hours and calcine at 350 °C for 8 hours to obtain the heating aid.

[0067] The resulting heating aid contains 4 wt% Cu oxide, 17 wt% Ca oxide, 0.5 wt% element IVA oxide, and 78.5 wt% Al2O3 by mass percentage of oxides.

[0068] XRD pattern of the heating aid in Example 2 and Figure 1 Similarly, the carrier composition of the heating aid includes not only Al2O3 but also Ca3Al. 10 O 18 Ca3Al 10 O 18 The molar ratio of Al2O3 to Al2O3 is 0.17:1.

[0069] Example 3 (1) Weigh 500g of boehmite (calculated as Al2O3), 10g of guar gum powder, and 25g of nitric acid solution (nitric acid concentration of 60wt%). The boehmite and guar gum powder are mixed at room temperature for 25 minutes, then the nitric acid solution is added, and the mixture is stirred and kneaded for another 25 minutes to form a dough. The dough is then extruded into a cylindrical shape. Sample I is dried in an oven at 120℃ for 12 hours and then calcined at 1300℃ for 8 hours to obtain sample II after high-temperature calcination.

[0070] (2) Dissolve 84.22 g of calcium nitrate tetrahydrate and 1.87 g of lead chloride in 13.9 g of water to prepare a solution. Weigh 69.5 g of calcined sample II and place it in the solution for equal volume impregnation. Then dry at 120 °C for 16 hours and calcin at 1000 °C for 8 hours to obtain sample III. (3) Dissolve 27.34 g of copper nitrate trihydrate in 13.9 g of water to prepare a solution. Place sample III in the solution for an equal volume immersion, then dry at 120°C for 16 hours and calcine at 350°C for 8 hours to obtain the exothermic agent.

[0071] The resulting heating aid contains 9 wt% Cu oxide, 20 wt% Ca oxide, 1.5 wt% element IVA oxide, and 69.5 wt% Al2O3 by mass percentage of oxides.

[0072] XRD pattern of the heating agent in Example 3 and Figure 1 Similarly, the carrier composition of the heating aid includes not only Al2O3 but also Ca3Al. 10 O 18 Ca3Al 10 O 18The molar ratio of Al2O3 to Al2O3 is 0.25:1.

[0073] Example 4 The method described in Example 1 is different in that, in step (2), 78g of calcined sample II is weighed; in step (3), the amount of copper nitrate trihydrate used is 9.11g; and the heating aid is obtained.

[0074] The resulting heating aid contains 3 wt% Cu oxide, 18 wt% Ca oxide, 1 wt% element IVA oxide, and 78 wt% Al2O3 by mass percentage of oxides.

[0075] XRD pattern of the heating aid in Example 4 and Figure 1 Similarly, the carrier composition of the heating aid includes not only Al2O3 but also Ca3Al. 10 O 18 Ca3Al 10 O 18 The molar ratio of Al2O3 to Al2O3 is 0.21:1.

[0076] Example 5 The method described in Example 1 is different except that in step (2), the amount of calcium nitrate tetrahydrate used is 92.64g; 69.5g of calcined sample II is weighed; and the heating aid is obtained.

[0077] The resulting heating aid contains 7.5 wt% Cu oxide, 22 wt% Ca oxide, 1 wt% element IVA oxide, and 69.5 wt% Al2O3 by mass percentage of oxides.

[0078] XRD pattern of the heating aid in Example 5 and Figure 1 Similarly, the carrier composition of the heating aid includes not only Al2O3 but also Ca3Al. 10 O 18 Ca3Al 10 O 18 The molar ratio of Al2O3 to Al2O3 is 0.24:1.

[0079] Example 6 The method described in Example 1 is different except that in step (2), the amount of germanium chloride dihydrate is 0.62g; 70.2g of calcined sample II is weighed; and the heating aid is obtained.

[0080] The resulting heating aid contains 7.5 wt% Cu oxide, 18 wt% Ca oxide, 0.3 wt% element IVA oxide, and 70.2 wt% Al2O3 by mass percentage of oxides.

[0081] XRD pattern of the heating aid in Example 6 and Figure 1Similarly, the carrier composition of the heating aid includes not only Al2O3 but also Ca3Al. 10 O 18 Ca3Al 10 O 18 The molar ratio of Al2O3 to Al2O3 is 0.14:1.

[0082] Example 7 The method described in Example 1 is different except that in step (1), the calcination temperature is reduced from 1300°C to 950°C to obtain the heating aid.

[0083] The resulting heating aid contains 7.5 wt% Cu oxide, 18 wt% Ca oxide, 1 wt% element IVA oxide, and 73.5 wt% Al2O3 by mass percentage of oxides.

[0084] XRD pattern of the heating aid in Example 7 and Figure 1 Similarly, the carrier composition of the heating aid includes not only Al2O3 but also Ca3Al. 10 O 18 Ca3Al 10 O 18 The molar ratio of Al2O3 to Al2O3 is 0.11:1.

[0085] Comparative Example 1 The method described in Example 1 was followed, except that it did not contain Ca or IVA oxides during preparation; 92.5 grams of calcined sample II was weighed; the remaining components and contents were the same as in Example 1.

[0086] The resulting heating agent contains 7.5 wt% CuO and 92.5 wt% carrier by weight.

[0087] The heat-inducing agent does not contain Ca3Al 10 O 18 Crystal structure.

[0088] Figure 2 This is the XRD pattern of the heating aid in Comparative Example 1, from... Figure 2 It can be known that the carrier of the fever-inducing agent does not contain Ca3Al. 10 O 18 Its crystal structure consists only of Al2O3.

[0089] Comparative Example 2 The method described in Example 1 was followed, except that IVA oxide was not included in the preparation; 74.5 grams of calcined sample II were weighed; the remaining components and contents were the same as in Example 1.

[0090] The resulting heating agent contains 7.5 wt% CuO, 18 wt% CaO, and 74.5 wt% carrier by weight percentage.

[0091] The heat-inducing agent does not contain Ca3Al 10 O 18 Crystal structure.

[0092] XRD pattern of the exothermic agent in Comparative Example 2 and Figure 2 similar.

[0093] Comparative Example 3 The method described in Example 1 is different except that in step (2), 2.05g of germanium chloride dihydrate is replaced with 15.93g of cerium ammonium nitrate; 73.5g of calcined sample II is weighed.

[0094] The resulting heating agent contains 7.5 wt% CuO, 18 wt% CaO, 1 wt% CeO2, and 73.5 wt% carrier by weight percentage.

[0095] The heat-inducing agent does not contain Ca3Al 10 O 18 Crystal structure.

[0096] XRD pattern of the exothermic agent in Comparative Example 3 and Figure 2 similar.

[0097] Comparative Example 4 The method described in Example 1 is different except that in step (2), the amount of calcium nitrate tetrahydrate used is 63.16g. The resulting heating aid contains 7.5 wt% CuO, 15 wt% CaO, 1 wt% element IV oxides, and 73.5 wt% carrier by weight percentage.

[0098] The heat-inducing agent does not contain Ca3Al 10 O 18 Crystal structure.

[0099] XRD pattern of the exothermic agent in Comparative Example 4 and Figure 2 similar.

[0100] Test case The preparation method of propane dehydrogenation catalyst includes: weighing 57.39 g of chromium nitrate hexahydrate, 2.37 g of potassium nitrate, and 6.96 g of zirconium nitrate pentahydrate, adding them to 100 mL of deionized water, then adding 85.7 g of γ-alumina support, adjusting the pH of the solution to 3.5 with 2.5% ammonia, then immersing the sample in an 80°C water bath for 1 hour, removing the sample for filtration, drying it in a 120°C oven for 16 hours, and then calcining the sample in a muffle furnace at 800°C for 6 hours to obtain the desired catalyst.

[0101] The exothermic additives prepared in the examples and comparative examples were mixed with propane dehydrogenation catalysts at a volume ratio of 1:1, and their performance was tested. The test methods included: Pure propane gas is fed into the preheating zone via a mass flow meter to regulate its flow rate, and then enters the reaction zone. Both the heating and reaction sections of the reactor are heated by electric heating wires. The reactor operates at a temperature of 600℃, a pressure of 0.1 MPa, and a mass hourly space velocity (HHSV) of 1 h⁻¹. -1 Under the specified conditions, propane, a mixture of heat-generating accelerator and catalyst, and other components were reacted in an adiabatic manner for 10 minutes. The resulting gas was then condensed and analyzed using an Agilent 7890A gas chromatograph. A heating coupler was placed in the middle of the dehydrogenation catalyst bed to monitor the temperature changes during the reaction in real time. The temperature drop was the decrease in temperature during the reaction in the adiabatic bed reactor and was read directly from the temperature display.

[0102] Test the reaction-regeneration cycle performance of the heating aid: The heating aid was mixed with the catalyst and subjected to alkane dehydrogenation reaction for 10 min, and then regenerated and recycled. The regeneration conditions were charring at 600℃ and 20 mL / min in air atmosphere for 2 h.

[0103] The conversion rate of propane (%) = (mass of propane in reactants - mass of propane in reaction products) ÷ mass of propane in reactants × 100%; Selectivity of propylene (%) = Actual yield of propylene ÷ Theoretical yield of propylene × 100%, by mass.

[0104] The gaseous raw material is a commercially available product from Nanjing Tianze Company.

[0105] Table 1 shows the temperature drop, conversion rate, selectivity, and results after 10 min of adiabatic contact reaction of propane, heating material, and propane dehydrogenation catalyst, as well as the results after 100 reaction-regeneration cycles.

[0106] Table 1

[0107] The results above show that when the heating aid provided by this invention is mixed with the catalyst and used in the propane dehydrogenation to propylene reaction, it effectively suppresses the decrease in temperature during the reaction process, improves the conversion rate of propane and the selectivity of propylene, and has good regeneration ability. After 100 reaction-regeneration cycles, it still effectively suppresses the decrease in temperature during the reaction process, and the conversion rate of propane and the selectivity of propylene do not decrease significantly.

[0108] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A heating aid, characterized in that, Based on the total amount of the heating aid, it includes the following components: a) 1-10 wt% Cu oxide; b) 0.01-2 wt% of Group IVA element oxides; c) 16-22 wt% Ca oxides; d) 66-82 wt% carrier; The heating aid contains Ca3Al 10 O 18 Crystal structure.

2. The heating aid according to claim 1, wherein, The carrier is Al2O3, and the Ca3Al 10 O 18 The molar ratio of Al2O3 to Al2O3 is 0.1-0.4:1, preferably 0.15-0.3:1; Preferably, the IVA group element is selected from at least one of Pb, Ge, and Sn; Preferably, the mass ratio of the Ca oxide to the Group IVA element oxide is 8-40:1, more preferably 12-40:

1.

3. The heating aid according to claim 1 or 2, wherein, The heating aid contains a carrier modified with Ca oxide and group IVA element oxides, and Cu oxide loaded on the modified carrier; Preferably, the carrier is a molded carrier, selected from at least one of cylinder, trilobal strip, tetralobal strip and sphere.

4. The heating aid according to any one of claims 1-3, wherein, Based on the total amount of the heating aid, it includes the following components: 4-9 wt% Cu oxide; 0.5-1.5 wt% Group IVA element oxides; 17-20 wt% Ca oxide; and 68-78 wt% carrier.

5. A method for preparing the heating aid according to any one of claims 1-4, characterized in that, The method includes: The carrier is loaded by contacting a Ca source, a Group IVA element source, and a Cu source, and then dried and calcined to obtain the exothermic agent.

6. The method according to claim 5, wherein, The carrier is a molded carrier, selected from at least one of cylinder, trilobal strip, tetralobal strip and sphere.

7. The method according to claim 5 or 6, wherein, The method includes: (1) The support, Ca source and Group IVA element source are brought into first contact, and then dried and calcined to obtain the modified support; (2) The Cu source and the modified support are brought into a second contact, and then dried and calcined to obtain the heating aid.

8. The method according to claim 7, wherein, The first contact and the second contact are each independently selected from at least one of the following methods: impregnation, precipitation, spraying and mixing, preferably impregnation, and more preferably equal volume impregnation. Preferably, the temperature of the first roasting is higher than the temperature of the second roasting; Preferably, the temperature of the first calcination is 900-1200℃, more preferably 1000-1100℃; Preferably, the second calcination temperature is 300-500℃, more preferably 350-450℃; Preferably, the first and second roasting times are each 4-24 hours, more preferably 6-12 hours; Preferably, the drying conditions in step (1) include: a temperature of 80-150℃ and a time of 6-24h; Preferably, the drying conditions in step (2) include: a temperature of 80-150℃ and a time of 6-24h.

9. The application of the heating aid according to any one of claims 1-4 in the dehydrogenation reaction of alkane, wherein the alkane is preferably a C6 or less alkane, more preferably propane.

10. A method for dehydrogenation reaction of an alkane, characterized in that, The alkane dehydrogenation reaction is carried out in the presence of the heating aid described in any one of claims 1-4 and the alkane dehydrogenation catalyst, wherein the alkane is preferably an alkane with C6 or less, and more preferably propane; Preferably, the volume ratio of the heating aid to the propane dehydrogenation catalyst is 0.2-1.2:1; Preferably, the conditions for the propane dehydrogenation reaction include: a temperature of 500-650℃, a pressure of 0.05-0.15 MPa, and a mass hourly space velocity of 0.5-5 h⁻¹. -1 .

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