Electro-response type propane dehydrogenation catalyst as well as preparation method and application thereof
By promoting the dehydrogenation of propane to propylene using an electroresponsive catalyst, the problems of high energy consumption at high temperatures and low efficiency at low temperatures have been solved, and efficient propylene production at low temperatures has been achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-14
- Publication Date
- 2026-04-07
AI Technical Summary
Propane dehydrogenation reactions are energy-intensive at high temperatures and inefficient at low temperatures, making it difficult to achieve high propylene yields and selectivity with existing technologies.
An electroresponsive catalyst containing titanium-aluminum composite oxide and doped GaOx is used to promote the dehydrogenation of propane to propylene through electric field-assisted thermal catalysis, thereby improving the catalyst's conductivity and dehydrogenation activity.
It significantly improves propane conversion and propylene selectivity under low-temperature conditions, reduces energy consumption, and enhances catalyst activity and selectivity.
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Figure CN121797294A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of catalyst technology, specifically relating to an electroresponsive propane dehydrogenation catalyst and its preparation method, and the application of the catalyst in propane dehydrogenation to propylene. Background Technology
[0002] Propylene is an important basic chemical raw material, widely used in the production of various high-value chemical intermediates such as acrylic acid, acrylonitrile, and propylene oxide. These chemical intermediates are widely used in the production of plastics, home appliances, medical devices, synthetic fibers, cosmetics, and are crucial to human survival and life. The main production processes for propylene include catalytic cracking (FCC) and steam cracking, methanol-to-olefins (MTO), and propane dehydrogenation (PDH). Among these, propane dehydrogenation has a single feedstock, a short process flow, simple operation, and high selectivity and yield of propylene. Furthermore, in recent years, the large-scale extraction and development of shale gas globally has made the feedstock for propane dehydrogenation more inexpensive and readily available, providing favorable conditions for the further development of this technology.
[0003] Because the propane dehydrogenation reaction is a strongly endothermic reaction that increases the number of molecules (ΔH) 298 k θ = + 124.3 kJ mol -1 Due to the limitations of the reaction's thermodynamic properties, achieving high propylene yields requires high-temperature conditions (T ≥ 600℃). This necessitates a continuous supply of large amounts of heat, leading to high energy consumption, high material consumption, and high costs. Therefore, developing efficient catalytic systems for propylene production at low temperatures is of great significance.
[0004] In recent years, electric field-assisted thermocatalysis (EDT) has provided a new strategy for addressing the problems of high energy consumption and low reaction efficiency in strongly endothermic catalytic reactions. Studies have confirmed that this technology can significantly improve the conversion rates of various strongly endothermic reactions, such as methylcyclohexane dehydrogenation, ammonia synthesis, and methane dry reforming, under low-temperature conditions. The development of electroresponsive catalysts is the core driver of the advancement of EDT. Summary of the Invention
[0005] Based on the above, the purpose of this invention is to provide an electroresponsive propane dehydrogenation catalyst, its preparation method, and its application. This catalyst, under the action of electro-assisted reaction, can improve the propane conversion rate and selectivity of the propane dehydrogenation reaction, especially under low temperature conditions, and can solve the problems of high energy consumption and low reaction efficiency at low temperatures in the propane dehydrogenation reaction.
[0006] A first aspect of the present invention provides an electroresponsive propane dehydrogenation catalyst comprising a titanium-aluminum composite oxide and GaO doped in the titanium-aluminum composite oxide. x0 < x < 3 / 2; the molar ratio of titanium to aluminum in the titanium-aluminum composite oxide is 1-9. 1.
[0007] A second aspect of the present invention provides a method for preparing the above-described electroresponsive propane dehydrogenation catalyst, the method comprising the following steps: 1) Prepare a mixed solution containing Ga source, Ti source and Al source, then add urea, crystallize in a high pressure hydrothermal reactor, separate solid and liquid, wash and dry the solid to obtain the catalyst precursor; 2) The catalyst precursor is calcined and reduced to obtain the catalyst.
[0008] A third aspect of the invention provides the application of the above-described electroresponsive propane dehydrogenation catalyst in the propane dehydrogenation to propylene.
[0009] Compared with the prior art, the present invention has the following beneficial effects: In the catalyst of this invention, the semiconductor TiAl composite oxide possesses suitable conductivity and can be doped to introduce dehydrogenation active centers, which is beneficial for the dispersion and stability of Ga. Applying an electric field to the electric field-assisted thermocatalytic system allows for the simultaneous polarization of Ga-H and OH groups on the catalyst surface. These two groups synergistically act on adjacent CH bonds in propane, promoting the simultaneous dehydrogenation of propane to propylene and enhancing the dehydrogenation activity. The catalyst of this invention can significantly improve the propylene yield while maintaining excellent propylene selectivity. Moreover, the propane dehydrogenation conversion rate under electric field-assisted thermocatalytic conditions is significantly higher than that under the same conditions for pure thermocatalysis, especially with a more pronounced enhancement effect at low temperatures.
[0010] Other features and advantages of the present invention will be described in detail in the following detailed description section. Detailed Implementation
[0011] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.
[0012] According to a first aspect of the present invention, an electroresponsive propane dehydrogenation catalyst is provided, the catalyst comprising a titanium-aluminum composite oxide and GaO doped in the titanium-aluminum composite oxide. x 0 < x < 3 / 2; the molar ratio of titanium to aluminum in the titanium-aluminum composite oxide is 1-9. 1.
[0013] In this invention, Ga is used in the form of its oxide GaO. xThe Ga exists in the form of x, with the valence state between 0 and +3, therefore, 0 < x < 3 / 2. The Ga content, based on the total weight of the catalyst, can be 0.2-6 wt%, preferably 1.5-6 wt%.
[0014] According to the present invention, the molar ratio of titanium to aluminum in the titanium-aluminum composite oxide can be 9:1, 8:2, 7:3, 6:4, 5:5, etc., preferably 1-4:1.
[0015] In the catalyst of this invention, the TiAl composite oxide is in the form of nanoparticles; GaO x In monodisperse form or GaO x Clusters are highly dispersed in the TiAl composite oxide.
[0016] According to a second aspect of the present invention, the present invention provides a method for preparing the above-described electroresponsive propane dehydrogenation catalyst, the method comprising the following steps: 1) Prepare a mixed solution containing Ga source, Ti source and Al source, then add urea, crystallize in a high pressure hydrothermal reactor, separate solid and liquid, wash and dry the solid to obtain the catalyst precursor; 2) The catalyst precursor is calcined and reduced to obtain the catalyst.
[0017] In this invention, the preparation of the mixed solution includes: adding Ga source and Al source to deionized water, dissolving by sonication, and then adding Ti source and continuing sonication for 0.5-1.5 h.
[0018] According to the present invention, the Ga source can be Ga(NO3)3xH2O, the Ti source can be Ti(SO4)2, and the Al source can be Al2(SO4)318H2O or Al(NO3)3.
[0019] In this invention, the amounts of Ga, Ti, and Al sources can be set as needed, and the amount of urea can be set according to existing technology; for example, the molar ratio of urea to total metal ions can be 2.8. 1.
[0020] According to the present invention, the crystallization conditions may include crystallization at 120-150°C for 8-12 hours. Crystallization can be carried out by placing a high-pressure hydrothermal reactor in a constant-temperature drying oven.
[0021] Preferably, the drying conditions include a drying temperature of 60-80°C and a drying time of 6-12 hours. More preferably, drying at 65°C for 12 hours is preferred. Drying can be carried out in a forced-air drying oven.
[0022] In this invention, the calcination conditions may include: calcination at 500-650℃ for 2-4 hours, with a heating rate of 2-10℃ / min. Preferably, calcination is carried out at 600℃ for 4 hours, with a heating rate of 5℃ / min. Calcination can be performed in a muffle furnace.
[0023] According to the present invention, the conditions for reduction treatment may include: reduction at 550-650°C for 1-3 hours in an atmosphere containing H2, with a heating rate of 2-10°C / min and a gas flow rate of 30-60 mL / min.
[0024] Preferably, the atmosphere containing H2 can be H2 / Ar (H2 content is 10-20 vol.%) or a pure H2 atmosphere.
[0025] More preferably, the reduction is carried out at 550°C for 1 h in a 20 vol% H2 / Ar atmosphere, with a heating rate of 5°C / min and a flow rate of 30 mL / min for the 20 vol% H2 / Ar.
[0026] According to a third aspect of the present invention, the present invention provides the application of the above-described electroresponsive propane dehydrogenation catalyst in the propane dehydrogenation to propylene.
[0027] Preferably, propane dehydrogenation is carried out under the assistance of an electric field. Specifically, a current of 15 mA is applied to the catalyst bed using a regulated DC power supply, while other conditions are consistent with those of conventional thermocatalysis.
[0028] In this invention, the conditions for propane dehydrogenation may include: a reaction temperature of 350-600℃; and a reaction pressure of atmospheric pressure.
[0029] According to the present invention, the reaction feedstock can be conventional materials used in the prior art, such as C3H8, Ar, and H2, with a molar ratio of C3H8:H2:Ar = 1:2:17; the propane mass hourly space velocity can be 0.7-2.8 h⁻¹. -1 The amount of catalyst used can be 0.2-0.4 g.
[0030] The substances and parameters not limited in this invention can be selected according to existing technology, which is a conventional technical means in this field.
[0031] The present invention will be further described below with reference to embodiments. However, the invention is not limited to these embodiments.
[0032] Example 1
[0033] Weigh 0.2 mmol Ga(NO3)3 xH2O and 6.0 mmol Al2(SO4)3 18H₂O was dissolved in 80 mL of deionized water to obtain solution A. Then, 27.9 mmol of Ti(SO₄)₂ was weighed and added to solution A, and the solution was sonicated for 1 h to obtain solution B. Finally, 112.0 mmol of urea was weighed and added to solution B and dispersed evenly. The resulting solution was placed in a 200 mL high-pressure hydrothermal reactor and crystallized at 150 °C for 8 h. The precipitate after hydrothermal treatment was centrifuged and washed until the pH of the supernatant was neutral, and then dried in a 60 °C oven. Subsequently, the sample was ground into powder and calcined in a muffle furnace at a heating rate of 5 °C / min to 600 °C for 4 h. Finally, the temperature was increased to 550 °C in an Ar atmosphere at a rate of 5 °C / min, and then reduced with 20 vol% H₂ / Ar for 1 h to prepare a 0.5 wt% Ga-Ti₇Al₃O₃ catalyst. x Its actual Ga content is 0.5 wt%, and the Ti:Al molar ratio is 7. 3.
[0034] Example 2
[0035] Weigh 0.4 mmol Ga(NO3)3 xH2O and 6.2 mmol Al2(SO4)3 Solution A was obtained by dissolving 18H₂O in 80 mL of deionized water. Then, 29.1 mmol of Ti(SO₄)₂ was weighed and added to solution A, and the solution was sonicated for 1 h to obtain solution B. Finally, 112.0 mmol of urea was weighed and added to solution B and dispersed evenly. The resulting solution was placed in a 200 mL high-pressure hydrothermal reactor and crystallized at 150 °C for 8 h. The precipitate after hydrothermal treatment was centrifuged and washed until the pH of the supernatant was neutral. It was then dried in a 60 °C oven for 12 h. Subsequently, the sample was ground into powder and calcined in a muffle furnace at 5 °C / min to 600 °C for 4 h. Finally, the temperature was increased to 550 °C in an Ar atmosphere at a rate of 5 °C / min, and then the reaction was switched to 20 vol% H₂ / Ar reduction for 1 h to prepare a catalyst of 0.8 wt% Ga-Ti₇Al₃O₃. x Its actual Ga content is 0.8 wt%, and the Ti:Al molar ratio is 7. 3.
[0036] Example 3
[0037] Weigh 1.2 mmol Ga(NO3)3 xH2O and 5.8 mmol Al2(SO4)3 18H₂O was dissolved in 80 mL of deionized water to obtain solution A. Then, 27.2 mmol of Ti(SO₄)₂ was weighed and added to solution A, and the solution was sonicated for 1 h to obtain solution B. Finally, 112.0 mmol of urea was weighed and added to solution B and dispersed evenly. The resulting solution was placed in a 200 mL high-pressure hydrothermal reactor and crystallized at 150 °C for 8 h. The precipitate after hydrothermal treatment was centrifuged and washed until the pH of the supernatant was neutral. It was then dried in a 60 °C oven for 12 h. Subsequently, the sample was ground into powder and calcined in a muffle furnace at 5 °C / min to 600 °C for 4 h. Finally, the temperature was increased to 550 °C in an Ar atmosphere at a rate of 5 °C / min, and then reduced with 20 vol% H₂ / Ar for 1 h to prepare a catalyst of 2.5 wt% Ga-Ti₇Al₃O₃. x Its actual Ga content is 2.5 wt%, and the Ti:Al molar ratio is 7. 3.
[0038] Example 4
[0039] Weigh 2.1 mmol Ga(NO3)3 xH2O and 5.9 mmol Al2(SO4)3 Solution A was obtained by dissolving 18H₂O in 80 mL of deionized water. Then, 27.5 mmol of Ti(SO₄)₂ was weighed and added to solution A, and the solution was sonicated for 1 h to obtain solution B. Finally, 112.0 mmol of urea was weighed and added to solution B and dispersed evenly. The resulting solution was placed in a 200 mL high-pressure hydrothermal reactor and crystallized at 150 °C for 8 h. The precipitate after hydrothermal treatment was centrifuged and washed until the pH of the supernatant was neutral. It was then dried in a 60 °C oven for 12 h. Subsequently, the sample was ground into powder and calcined in a muffle furnace at 5 °C / min to 600 °C for 4 h. Finally, the temperature was increased to 550 °C in an Ar atmosphere at a rate of 5 °C / min, and then reduced with 20 vol% H₂ / Ar for 1 h to prepare a catalyst of 4.2 wt% Ga-Ti₇Al₃O₃. x Its actual Ga content is 4.2 wt%, and the Ti:Al molar ratio is 7. 3.
[0040] Example 5
[0041] Weigh 3.0 mmol Ga(NO3)3 xH2O and 5.7 mmol Al2(SO4)3 18H₂O was dissolved in 80 mL of deionized water to obtain solution A. Then, 26.7 mmol of Ti(SO₄)₂ was weighed and added to solution A, and the solution was sonicated for 1 h to obtain solution B. Finally, 112.0 mmol of urea was weighed and added to solution B and dispersed evenly. The resulting solution was placed in a 200 mL high-pressure hydrothermal reactor and crystallized at 150 °C for 8 h. The precipitate after hydrothermal treatment was centrifuged and washed until the pH of the supernatant was neutral. It was then dried in a 60 °C oven for 12 h. Subsequently, the sample was ground into powder and calcined in a muffle furnace at 5 °C / min to 600 °C for 4 h. Finally, the temperature was increased to 550 °C in an Ar atmosphere at a rate of 5 °C / min, and then reduced with 20 vol% H₂ / Ar for 1 h to prepare a catalyst of 5.8 wt% Ga-Ti₇Al₃O₃. x Its actual Ga content is 5.8 wt%, and the Ti:Al molar ratio is 7. 3.
[0042] Example 6
[0043] Weigh 1.2 mmol Ga(NO3)3 xH2O and 7.8 mmol Al2(SO4)3 Solution A was obtained by dissolving 18H₂O in 80 mL of deionized water. Then, 23.3 mmol of Ti(SO₄)₂ was weighed and added to solution A, and the solution was sonicated for 1 h to obtain solution B. Finally, 112.0 mmol of urea was weighed and added to solution B and dispersed evenly. The resulting solution was placed in a 200 mL high-pressure hydrothermal reactor and crystallized at 150 °C for 8 h. The precipitate was centrifuged and washed until the pH of the supernatant was neutral, then dried in a 60 °C oven for 12 h. The sample was then ground into powder and calcined in a muffle furnace at 5 °C / min to 600 °C for 4 h. Finally, the temperature was increased to 550 °C in an Ar atmosphere at a rate of 5 °C / min, and then reduced with 20 vol% H₂ / Ar for 1 h to prepare a 2.5 wt% Ga-Ti₆Al₄O₂ catalyst. x Its actual Ga content is 2.5 wt%, and the Ti:Al molar ratio is 6. 4.
[0044] Comparative Example 1
[0045] Weigh out 6.0 mmol Al2(SO4)3 18H₂O was dissolved in 80 mL of deionized water to obtain solution A. Then, 28.0 mmol of Ti(SO₄)₂ was weighed and added to solution A, and the solution was sonicated for 1 h to obtain solution B. Finally, 112.0 mmol of urea was weighed and added to solution B and dispersed evenly. The resulting solution was placed in a 200 mL high-pressure hydrothermal reactor and crystallized at 150 °C for 8 h. The precipitate after hydrothermal treatment was centrifuged and washed until the pH of the supernatant was neutral. It was then dried in a 60 °C oven for 12 h. Subsequently, the sample was ground into powder and calcined in a muffle furnace at 5 °C / min to 600 °C for 4 h. Finally, the temperature was increased to 550 °C in an Ar atmosphere at a rate of 5 °C / min, and then reduced with 20 vol% H₂ / Ar for 1 h to prepare the catalyst Ti₇Al₃O₃. x The Ti:Al molar ratio is 7. 3.
[0046] Comparative Example 2
[0047] Weigh 0.89 mmol Ga(NO3)3 xH2O and 19.6 mmol Al2(SO4)3 18H₂O was dissolved in 80 mL of deionized water to obtain solution A. 112.0 mmol of urea was then weighed and added to solution A, dispersed evenly, and the resulting solution was placed in a 200 mL high-pressure hydrothermal reactor and crystallized at 150 °C for 8 h. The precipitate was then centrifuged and washed until the pH of the supernatant was neutral, and dried in a 60 °C oven for 12 h. The sample was then ground into powder and calcined in a muffle furnace at 5 °C / min to 600 °C for 4 h. Finally, the temperature was increased to 550 °C in an Ar atmosphere at a rate of 5 °C / min, and then reduced with 20 vol% H₂ / Ar for 1 h to prepare a 2.5 wt% Ga-AlO₂ catalyst. x .
[0048] The catalysts prepared in each example and comparative example were pressed into 20-40 mesh granular catalysts. These granular catalysts were then loaded into a fixed-bed reactor and pretreated with H2 / Ar at a flow rate of 30 mL / min, maintained at 550°C for 1 h. Thermocatalytic and electro-assisted thermocatalytic performance were then tested by introducing reactants at 550°C or 450°C, with a current of 15 mA in the electro-assisted thermocatalytic mode. The reaction pressure was atmospheric pressure, and the feed consisted of C3H8, Ar, and H2 in a molar ratio of C3H8:H2:Ar = 1:2:17; the propane mass hourly space velocity (HHSV) was 0.7 h⁻¹. -1 The catalyst dosage was 0.4 g. The catalytic results of each example and comparative example are shown in Table 1.
[0049] Table 1
[0050] As shown in Table 1, compared with the comparative example, the catalyst of the present invention has a higher propylene yield and is electric field responsive, and the propane dehydrogenation performance can be significantly improved after applying a current of 15 mA.
[0051] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.
Claims
1. An electroresponsive propane dehydrogenation catalyst, characterized in that, The catalyst contains titanium-aluminum composite oxide and GaO doped in the titanium-aluminum composite oxide. x 0 < x < 3 / 2; the molar ratio of titanium to aluminum in the titanium-aluminum composite oxide is 1-9.
1.
2. The electroresponsive propane dehydrogenation catalyst according to claim 1, wherein, The Ga content is 0.2-6 wt% based on the total weight of the catalyst.
3. The method for preparing the electroresponsive propane dehydrogenation catalyst according to claim 1 or 2, characterized in that, The preparation method includes the following steps: 1) Prepare a mixed solution containing Ga source, Ti source and Al source, then add urea, crystallize in a high pressure hydrothermal reactor, separate solid and liquid, wash and dry the solid to obtain the catalyst precursor; 2) The catalyst precursor is calcined and reduced to obtain the catalyst.
4. The method for preparing the electroresponsive propane dehydrogenation catalyst according to claim 3, wherein, The preparation of the mixed solution includes: adding Ga source and Al source to deionized water, dissolving by sonication, then adding Ti source and continuing sonication for 0.5-1.5 h.
5. The method for preparing the electroresponsive propane dehydrogenation catalyst according to claim 3 or 4, wherein, The Ga source is Ga(NO3)3xH2O, the Ti source is Ti(SO4)2, and the Al source is Al2(SO4)318H2O or Al(NO3)3.
6. The method for preparing the electroresponsive propane dehydrogenation catalyst according to claim 3, wherein, The crystallization conditions include crystallization at 120-150℃ for 8-12 h; the drying conditions include drying temperature of 60-80℃ and drying time of 6-12 h.
7. The method for preparing the electroresponsive propane dehydrogenation catalyst according to claim 3, wherein, The calcination conditions include: calcination at 500-650℃ for 2-4 hours, with a heating rate of 2-10℃ / min.
8. The method for preparing the electroresponsive propane dehydrogenation catalyst according to claim 3, wherein, The reduction conditions include: reduction at 550-650℃ for 1-3 h in an atmosphere containing H2, with a heating rate of 2-10℃ / min and a gas flow rate of 30-60 mL / min.
9. The application of the electroresponsive propane dehydrogenation catalyst according to claim 1 or 2 in the propane dehydrogenation to propylene; preferably, the propane dehydrogenation is carried out under the assistance of an electric field.
10. The application of the electroresponsive propane dehydrogenation catalyst according to claim 9 in the propane dehydrogenation to propylene, wherein, The conditions for propane dehydrogenation include: a reaction temperature of 350-600℃ and a reaction pressure of atmospheric pressure.