Reducing exothermic material for propane dehydrogenation process and synthesis method and application thereof
By using rare earth-doped porous alumina to support CuO species, the lack of pore structure and instability of existing reduction heating materials were solved, achieving efficient heat transfer and material stability in propane dehydrogenation, and improving dehydrogenation efficiency and lifespan.
Patent Information
- Application Number
- CN202610737151.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-05-26
- Publication Date
- 2026-08-25
AI Technical Summary
The reduction heating materials used in the existing propane dehydrogenation process suffer from a lack of pore structure and unstable CuO species that are prone to sintering and agglomeration, which affect heat transfer and heating performance.
A copper-based active component is loaded onto a rare earth-doped porous alumina support. Through co-deposition and high-temperature calcination, a highly stable α-Al2O3 support is formed, which is then loaded with CuO species to form a high-performance reduction heating material.
It significantly improves the pore structure and stability of CuO species in the material, enhances heat transfer efficiency and reduction reaction effect, reduces energy consumption and extends the service life of the material.
Smart Images
Figure CN122628731A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of functionalized materials technology, and in particular to a reducing exothermic material for propane dehydrogenation processes, its synthesis method, and its application. Background Technology
[0002] Reduction-exothermic materials are a class of functionalized materials that can generate heat through reduction reactions in a reducing environment. A typical example is the reduction-exothermic material (HGM) used in propane dehydrogenation (PDH) processes. It is mixed with PDH catalysts and loaded into the reactor bed. In the reducing atmosphere of the propane dehydrogenation process, it provides heat for the strongly endothermic propane dehydrogenation reaction through a reduction-exothermic reaction, thereby greatly promoting the propane dehydrogenation reaction. Currently, such HGM materials are usually made by loading CuO species with reduction-exothermic properties onto an α-Al2O3 support. However, existing HGM materials have some significant defects that greatly limit their exothermic performance and are not conducive to further improving the propane dehydrogenation efficiency. These defects are as follows: (1) Conventional α-Al2O3 support materials are usually dense crystalline materials with a lack of internal pore structure, which is very unfavorable for heat transfer during the heating process and for improving the dispersion of CuO species. (2) CuO is mostly loaded by conventional impregnation methods. CuO species lack relevant stabilization mechanisms and are prone to sintering and agglomeration under the high-temperature process conditions of propane dehydrogenation.
[0003] Therefore, overcoming the defects of existing HGM materials in propane dehydrogenation processes and synthesizing novel high-performance reduction heating materials for propane dehydrogenation processes is an urgent technical challenge. Summary of the Invention
[0004] In view of this, to overcome the aforementioned shortcomings of existing reduction-exothermic materials, this invention provides a reduction-exothermic material for propane dehydrogenation processes, its synthesis method, and its application. By loading copper-based active components onto a rare-earth-doped porous alumina support, a composite functional material with both high reduction activity and high exothermic efficiency is prepared. This material can spontaneously release reaction heat during the reduction stage of the dehydrogenation process, achieving self-heating of the system. This material can maintain the reduction reaction temperature without additional heating, effectively reducing the energy consumption of the dehydrogenation process. Simultaneously, rare-earth doping can inhibit the sintering of active components, improving the material's cycle life.
[0005] To achieve the above objectives, the present invention provides the following technical solution: In a first aspect, the present invention provides a method for synthesizing a reducing exothermic material for a propane dehydrogenation process, comprising the following steps: Step (1): Mix aluminum source, rare earth source, α-Al2O3 seed crystals and deionized water, and obtain a porous support material after reaction, aging and calcination; wherein, the mass ratio of Al2O3 in aluminum source, La2O3 in rare earth source, α-Al2O3 seed crystals and deionized water is 1:(0.005~0.05):(0.001~0.01):(4~10); Step (2): Load the copper source onto the porous support material obtained in step (1), and calcine it to obtain the reduction heating material used in the propane dehydrogenation process; In step (2), the preferred mass ratio of porous carrier material to CuO in copper source is 1:0.05~0.2.
[0006] Secondly, the present invention provides a reducing heating material for propane dehydrogenation processes, which is synthesized by the above-described synthesis method.
[0007] Thirdly, the present invention provides the application of the above-mentioned reduction heating material for propane dehydrogenation process as a heating medium in the reduction reaction stage of the dehydrogenation process.
[0008] To address the shortcomings of existing propane dehydrogenation reduction heating materials, the synthesis method of this invention is based on the concept of "in-situ doping." First, an aluminum source, a rare earth source, and α-Al₂O₃ seeds are co-deposited to form a rare earth-doped porous alumina / α-Al₂O₃ composite precursor. Then, the resulting rare earth-doped porous alumina / α-Al₂O₃ composite precursor is calcined at high temperature, converting the porous alumina into highly stable α-Al₂O₃ species, thereby obtaining a highly stable porous support material. Finally, CuO species are loaded to synthesize a high-performance reduction heating material for propane dehydrogenation processes. Therefore, compared with existing technologies, this invention has the following significant advantages: (1) Because the porous alumina precursor will retain a certain amount of pore structure during the high-temperature calcination process to form α-Al2O3 species, it can significantly improve the pore structure properties of the carrier material and enhance its heat transfer performance. (2) Due to the excellent pore structure of the carrier material, the dispersion of CuO species can be significantly improved, which is beneficial to its reduction and exothermic reaction; (3) The rare earth species doped in the carrier structure can significantly improve the stability of CuO species and inhibit its sintering and agglomeration under high temperature conditions. (4) The introduction of α-Al2O3 seeds can promote the transformation of porous alumina precursors into highly stable α-Al2O3 species during calcination, thereby improving the stability of the support. (5) The present invention can significantly improve the pore structure and CuO species stability of the reducing heating material, thereby obtaining a high-performance reducing heating material, which will greatly improve the efficiency of the current propane dehydrogenation process. Attached Figure Description
[0009] Figure 1 The image shows the H2-TPR spectrum of the high-performance reducing exothermic material C1 synthesized in Example 1.
[0010] Figure 2 The image shows the H2-TPR spectrum of the high-performance reducing exothermic material C3 synthesized in Example 3.
[0011] Figure 3 The image shows the H2-TPR spectrum of the high-performance reducing exothermic material C5 synthesized in Example 5.
[0012] Figure 4 The H2-TPR spectrum of the comparative reduction exothermic material D1 synthesized in Comparative Example 1 is shown.
[0013] Figure 5 The H2-TPR spectrum of the comparative reduction exothermic material D3 synthesized in Comparative Example 3 is shown.
[0014] Figure 6 The H2-TPR spectrum of the comparative reduction exothermic material D5 synthesized in Comparative Example 5 is shown. Detailed Implementation
[0015] This invention provides a method for synthesizing a reducing exothermic material for propane dehydrogenation processes, characterized by comprising the following steps: Step (1): Mix aluminum source, rare earth source, α-Al2O3 seed crystal and deionized water, and obtain porous carrier material after reaction, aging and calcination; wherein, the mass ratio of Al2O3 in aluminum source, La2O3 in rare earth source, α-Al2O3 seed crystal and deionized water is 1: (0.005~0.05): (0.001~0.01): (4~10).
[0016] In step (1), the aluminum source is calcined at 900-1400℃ for 0.5-5 h, preferably in a muffle furnace. The aluminum source is at least one of aluminum chloride, aluminum sulfate, aluminum nitrate, and aluminum acetate, preferably aluminum nitrate. The rare earth source is at least one of lanthanum chloride, lanthanum sulfate, lanthanum nitrate, lanthanum perchlorate, and lanthanum acetate, preferably lanthanum nitrate. In step (1), the aluminum source, rare earth source, α-Al2O3 seed crystals, and deionized water are mixed and the pH of the system is adjusted to 7-10. Specifically, the aluminum source, rare earth source, α-Al2O3 seed crystals, and deionized water are mixed and heated to 50-95℃, and concentrated ammonia is slowly added dropwise while continuously stirring until the pH of the system is 7-10.
[0017] Step (2): Load the copper source onto the porous support material obtained in step (1), and calcine it to obtain the reduction heating material used in the propane dehydrogenation process; In step (2), the preferred mass ratio of the porous support material to CuO in the copper source is 1:0.05~0.2. In step (2), the calcination is preferably carried out at 550~800℃ for 1~6 h. In step (2), the copper source is at least one of copper chloride, copper sulfate, copper nitrate, copper acetate and copper perchlorate, preferably copper nitrate.
[0018] The specific steps (2) are as follows: the porous carrier material obtained in step (1), the copper source and an appropriate amount of deionized water are mixed and impregnated in equal volumes, dried and then calcined to obtain the reduction heating material used in the propane dehydrogenation process.
[0019] The synthesis method provided by this invention can significantly improve the pore structure and CuO species stability of the reducing heating material, thereby obtaining a high-performance reducing heating material, which can greatly improve the efficiency of dehydrogenation processes, such as the propane dehydrogenation process efficiency in the prior art.
[0020] The technical solution of the present invention will be clearly and thoroughly described below with reference to specific embodiments.
[0021] (1) Raw material specifications Aluminum nitrate nonahydrate (Al(NO3)3·9H2O), copper nitrate trihydrate (Cu(NO3)2·3H2O), lanthanum nitrate hexahydrate (La(NO3)3·6H2O), α-Al2O3 (crystallization >98%), and ammonia (25%) were all analytical grade reagents purchased from Sigma-Aldrich.
[0022] (2) Analytical methods The pore structure parameters of the samples were analyzed and tested using a Micromeritics ASAP3000 automated physical N2 adsorption-desorption instrument; the hydrogen reduction temperature of the CuO sample was determined using a hydrogen temperature programmed reduction (H2-TPR) instrument and an AutoChemII 2920 chemisorption instrument (Micromeritics, USA).
[0023] Example 1 (1) 367.6 g of aluminum nitrate nonahydrate, 0.67 g of lanthanum nitrate hexahydrate, 0.05 g of α-Al2O3 seed crystals and 200 g of deionized water were thoroughly mixed at room temperature, and then heated to 50 °C. Concentrated ammonia was slowly added dropwise while stirring continuously until the pH of the system was 7.5. Then, the mixture was allowed to stand for 6 h, filtered, washed and dried. Finally, the dried sample was calcined in a muffle furnace at 900 °C for 5 h to obtain a highly stable porous support material.
[0024] (2) Mix 50g of the high-stability porous carrier material obtained in (1), 7.6g of copper nitrate trihydrate and an appropriate amount of deionized water and impregnate them in equal volumes. After drying, calcine at 550℃ for 6 h to obtain the high-performance reducing heating material C1 used in propane dehydrogenation process.
[0025] Example 2 (1) 367.6 g of aluminum nitrate nonahydrate, 1.33 g of lanthanum nitrate hexahydrate, 0.1 g of α-Al2O3 seed crystals and 250 g of deionized water were thoroughly mixed at room temperature, and then heated to 60 °C. Concentrated ammonia was slowly added dropwise while stirring continuously until the pH of the system was 8. Then, the mixture was allowed to stand for 5 h, filtered, washed and dried. Finally, the dried sample was calcined in a muffle furnace at 1000 °C for 4 h to obtain a highly stable porous support material.
[0026] (2) Mix 50g of the high-stability porous carrier material obtained in (1), 12.2g of copper nitrate trihydrate and an appropriate amount of deionized water and impregnate them in equal volumes. After drying, calcine at 600℃ for 5 h to obtain the high-performance reducing heating material C2 for propane dehydrogenation process.
[0027] Example 3 (1) 367.6 g of aluminum nitrate nonahydrate, 2.66 g of lanthanum nitrate hexahydrate, 0.2 g of α-Al2O3 seed crystals and 300 g of deionized water were thoroughly mixed at room temperature, and then heated to 70 °C. Concentrated ammonia was slowly added dropwise while stirring continuously until the pH of the system was 8.5. Then, the mixture was allowed to stand for 4 h, filtered, washed and dried. Finally, the dried sample was calcined in a muffle furnace at 1100 °C for 3 h to obtain a highly stable porous support material.
[0028] (2) Mix 50g of the high-stability porous carrier material obtained in (1), 16.7g of copper nitrate trihydrate and an appropriate amount of deionized water and impregnate them in equal volumes. After drying, calcine at 650℃ for 4 h to obtain the high-performance reducing heating material C3 for propane dehydrogenation process.
[0029] Example 4 (1) 367.6 g of aluminum nitrate nonahydrate, 3.99 g of lanthanum nitrate hexahydrate, 0.3 g of α-Al2O3 seed crystals and 350 g of deionized water were thoroughly mixed at room temperature, and then heated to 80 °C. Concentrated ammonia was slowly added dropwise while stirring continuously until the pH of the system was 9. Then, the mixture was allowed to stand for 3 h, filtered, washed and dried. Finally, the dried sample was calcined in a muffle furnace at 1200 °C for 2 h to obtain a highly stable porous support material.
[0030] (2) Mix 50g of the high-stability porous carrier material obtained in (1), 21.3g of copper nitrate trihydrate and an appropriate amount of deionized water and impregnate them in equal volumes. After drying, calcine at 700℃ for 3 h to obtain the high-performance reducing heating material C4 for propane dehydrogenation process.
[0031] Example 5 (1) 367.6 g of aluminum nitrate nonahydrate, 5.32 g of lanthanum nitrate hexahydrate, 0.4 g of α-Al2O3 seed crystals and 400 g of deionized water were thoroughly mixed at room temperature, and then heated to 90 °C. Concentrated ammonia was slowly added dropwise while stirring continuously until the pH of the system was 9.5. Then, the mixture was allowed to stand for 2 h, filtered, washed and dried. Finally, the dried sample was calcined in a muffle furnace at 1300 °C for 1 h to obtain a highly stable porous support material.
[0032] (2) Mix 50g of the high-stability porous carrier material obtained in (1), 25.8g of copper nitrate trihydrate and an appropriate amount of deionized water and impregnate them in equal volumes. After drying, calcine at 750℃ for 2 h to obtain the high-performance reducing heating material C5 for propane dehydrogenation process.
[0033] Example 6 (1) 367.6 g of aluminum nitrate nonahydrate, 6.64 g of lanthanum nitrate hexahydrate, 0.5 g of α-Al2O3 seed crystals and 450 g of deionized water were thoroughly mixed at room temperature, and then heated to 95 °C. Concentrated ammonia was slowly added dropwise while stirring continuously until the pH of the system was 10. Then, the mixture was allowed to stand for 1 h, filtered, washed and dried. Finally, the dried sample was calcined in a muffle furnace at 1400 °C for 0.5 h to obtain a highly stable porous support material.
[0034] (2) Mix 50g of the high-stability porous carrier material obtained in (1), 30.3g of copper nitrate trihydrate and an appropriate amount of deionized water and impregnate them in equal volumes. After drying, calcine at 800℃ for 1 h to obtain the high-performance reducing heating material C6 for propane dehydrogenation process.
[0035] Comparative Example 1 After mixing 50 g of α-Al2O3, 7.6 g of copper nitrate trihydrate and an appropriate amount of deionized water, the mixture was impregnated in equal volumes, dried, and then calcined at 550 °C for 6 h to obtain the comparative reduction exothermic material D1.
[0036] Comparative Example 2 After mixing 50 g of α-Al2O3, 12.2 g of copper nitrate trihydrate and an appropriate amount of deionized water, the mixture was impregnated in equal volumes, dried, and then calcined at 600℃ for 5 h to obtain the comparative reduction exothermic material D2.
[0037] Comparative Example 3 After mixing 50 g of α-Al2O3, 16.7 g of copper nitrate trihydrate and an appropriate amount of deionized water, the mixture was impregnated in equal volumes, dried, and then calcined at 650 °C for 4 h to obtain the comparative reduction exothermic material D3.
[0038] Comparative Example 4 50 g of α-Al2O3, 21.3 g of copper nitrate trihydrate and an appropriate amount of deionized water were mixed and impregnated in equal volumes. After drying, the mixture was calcined at 700℃ for 3 h to obtain the comparative reduction exothermic material D4.
[0039] Comparative Example 5 50 g of α-Al2O3, 25.8 g of copper nitrate trihydrate and an appropriate amount of deionized water were mixed and impregnated in equal volumes. After drying, the mixture was calcined at 750℃ for 2 h to obtain the comparative reduction exothermic material D5.
[0040] Comparative Example 6 50 g of α-Al2O3, 30.3 g of copper nitrate trihydrate and an appropriate amount of deionized water were mixed and impregnated in equal volumes. After drying, the mixture was calcined at 800℃ for 1 h to obtain the comparative reduction exothermic material D6.
[0041] In the propane dehydrogenation process, the reducing exothermic material generates heat through the exothermic reduction of CuO species on its surface using hydrogen. Therefore, the ease of the reduction reaction of CuO species on the surface of the exothermic material determines its heating performance; the easier the reduction reaction, the better the heating performance. To this end, H2-TPR analysis was used to determine the H2 reduction temperature of CuO species in the exothermic materials synthesized in the examples and comparative examples. The results are shown in the appendix. Figures 1-6 As shown, the H2 reduction temperature range of the CuO species in the reducing heating materials synthesized in this invention (Examples 1, 3, and 5) is concentrated between 400 and 550 °C, while the H2 reduction temperature range of the heating materials synthesized in the comparative examples (Comparative Examples 1, 3, and 5) is concentrated between 650 and 800 °C, significantly higher than the former. This indicates that the CuO species on the surface of the heating materials synthesized by the method of this invention are more prone to H2 reduction reaction, and thus possess superior reducing heating performance.
[0042] The pore structure of the reducing heating materials synthesized in Examples 1-6 and Comparative Examples 1-6 was tested, and the results are shown in Table 1 below.
[0043] Table 1. Pore structure properties of different reducing exothermic materials
[0044] Table 1 lists the pore structure properties of different reduction heating materials. It can be seen that, compared with the comparative samples, the reduction heating materials synthesized by the method of the present invention have significantly higher specific surface area and pore volume, which will be very beneficial to improving the thermal conductivity and CuO species dispersion of the material, thereby improving the reduction heating performance of the synthesized reduction heating materials.
[0045] The above description is merely a preferred embodiment of the present invention. However, the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention should be covered within the scope of protection of the present invention.
Claims
1. A method for synthesizing a reducing exothermic material for propane dehydrogenation processes, characterized in that, Includes the following steps: Step (1): Mix aluminum source, rare earth source, α-Al2O3 seed crystals and deionized water, and obtain a porous support material after reaction, aging and calcination; wherein, the mass ratio of Al2O3 in aluminum source, La2O3 in rare earth source, α-Al2O3 seed crystals and deionized water is 1:(0.005~0.05):(0.001~0.01):(4~10); Step (2): Load the copper source onto the porous support material obtained in step (1), and calcine it to obtain the reduction heating material used in the propane dehydrogenation process; In step (2), the preferred mass ratio of porous carrier material to CuO in copper source is 1:0.05~0.
2.
2. The method for synthesizing a reducing exothermic material for propane dehydrogenation process according to claim 1, characterized in that, In step (1), the product is calcined at 900~1400℃ for 0.5~5 h.
3. The method for synthesizing a reducing exothermic material for propane dehydrogenation process according to claim 1, characterized in that, In step (2), the product is calcined at 550~800℃ for 1~6 hours.
4. The method for synthesizing a reducing exothermic material for propane dehydrogenation process according to claim 1, characterized in that, In step (1), the aluminum source is at least one of aluminum chloride, aluminum sulfate, aluminum nitrate and aluminum acetate, preferably aluminum nitrate.
5. The method for synthesizing a reducing exothermic material for propane dehydrogenation process according to claim 1, characterized in that, In step (1), the rare earth source is at least one of lanthanum chloride, lanthanum sulfate, lanthanum nitrate, lanthanum perchlorate and lanthanum acetate, with lanthanum nitrate being preferred.
6. The method for synthesizing a reducing exothermic material for propane dehydrogenation process according to claim 1, characterized in that, In step (2), the copper source is at least one of copper chloride, copper sulfate, copper nitrate, copper acetate and copper perchlorate, preferably copper nitrate.
7. The method for synthesizing a reducing exothermic material for propane dehydrogenation process according to claim 1, characterized in that, In step (1), the pH of the system is adjusted to 7-10 after mixing the aluminum source, rare earth source, α-Al2O3 seed crystals and deionized water.
8. A method for synthesizing a reducing exothermic material for propane dehydrogenation process according to any one of claims 1-7, characterized in that, Step (2) specifically involves mixing the porous carrier material obtained in step (1), the copper source, and an appropriate amount of deionized water, then impregnating them in equal volumes, drying them, and calcining them to obtain the reduction heating material used in the propane dehydrogenation process.
9. A reducing heating material for propane dehydrogenation process, characterized in that, Synthesized by the synthesis method according to any one of claims 1-8.
10. The application of the reduction heating material of claim 9 for propane dehydrogenation process as a heating medium in the reduction reaction stage of the dehydrogenation process.