Propane dehydrogenation membrane reactor based on functional ceramic membrane, propane dehydrogenation method and application
Through the dual hydrogen-permeable oxygen permeability and electrically driven permeability of the functional ceramic membrane, the low conversion rate and carbon deposits in propane dehydrogenation are solved, and efficient propane conversion and long-term stable operation of the catalyst are achieved.
Patent Information
- Application Number
- CN202510725470.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-31
- Publication Date
- 2025-08-19
AI Technical Summary
The existing propane dehydrogenation technology is affected by thermodynamic equilibrium limitations and carbon deposits, resulting in low conversion and short catalyst life.
A propane dehydrogenation film reactor using functional ceramic membranes uses its dual hydrogen-permeable oxygen permeability and applies a constant voltage through the current collector at high temperatures to achieve opposite penetration of hydrogen and oxygen, remove hydrogen from the reaction product and eliminate carbon deposits.
It improves the conversion rate of propane, extends the service life of the catalyst, and reduces the frequency of carbon deposits and the frequency of replacement.
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Figure CN120502286A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of inorganic membrane reactor applications and relates to functional ceramic membranes and propane dehydrogenation. Background Art
[0002] Propylene can be used to produce acrylonitrile, propylene oxide, isopropyl alcohol, phenol, acetone, butanol, octanol, acrylic acid and its esters, propylene glycol, epichlorohydrin, and synthetic glycerin. As one of the three fundamental raw materials for synthetic materials, global demand for propylene remains high. Traditional propylene production relies primarily on processes such as naphtha cracking and refinery catalytic cracking, but these methods suffer from relatively low propylene yields and product distribution limitations within the overall production process.
[0003] Propane dehydrogenation (PDH) technology, with its unique advantage of efficiently converting propane directly into propylene, has become a hot topic in research and industrial application in recent years, opening up a new path for propylene production. Compared to other propylene production methods, PDH has long been highly sought after due to its simple process, low investment, high selectivity, high yield, high conversion rate, and low by-product count.
[0004] Propane dehydrogenation is a process in which propane is selectively dehydrogenated to produce propylene using a catalyst. ΔH 298 o =124.3 kJ / mol). This reaction is highly endothermic and, limited by thermodynamic equilibrium, its equilibrium conversion is only approximately 50% at 600°C and 1 atmosphere. Increasing the reaction pressure further reduces the equilibrium conversion. Furthermore, carbon deposits form during catalyst use, requiring constant regeneration, significantly reducing efficiency and catalyst life.
[0005] Increasing the efficiency of propane dehydrogenation has always been one of the research directions of interest to researchers. However, the impact of thermodynamic equilibrium limitations and the generation of reaction carbon deposits on propane dehydrogenation efficiency has always been a pain point for many researchers. How to increase the conversion rate while reducing the impact of carbon deposits on the propane dehydrogenation reaction and extending the service life of the catalyst has become one of the important challenges currently faced. Summary of the Invention
[0006] In order to solve the above problems, the purpose of the present invention is to provide a propane dehydrogenation membrane reactor based on a functional ceramic membrane. The functional ceramic membrane in the membrane reactor has the ability to conduct mixed protons and oxygen ions at high temperatures, and has the performance of being permeable to both hydrogen and oxygen. Through the dual hydrogen and oxygen permeability, it can increase the propane conversion rate while slowing down the carbon deposition of the catalyst, thereby achieving efficient propane conversion and long-term stable operation of the catalyst.
[0007] The technical solutions adopted to achieve the purpose of this invention and solve its technical problems are:
[0008] [1] A propane dehydrogenation membrane reactor based on a functional ceramic membrane, comprising a housing (1), a propane dehydrogenation catalyst, and a functional ceramic membrane (2). The housing (1) is closed at both ends by external clamps (11), and the functional ceramic membrane (2) is open at both ends. The housing (1) and the functional ceramic membrane (2) are both tubular, and the functional ceramic membrane (2) is located inside the housing (1).
[0009] The area between the functional ceramic membrane (2) and the housing (1) forms a reaction zone (5), and the reaction zone (5) is located in the middle of the functional ceramic membrane (2) and is loaded with a propane dehydrogenation catalyst (4).
[0010] A purge zone (6) is formed inside the functional ceramic membrane (2), and current collectors (3) are attached to the inner and outer surfaces of the functional ceramic membrane (2).
[0011] Clamps (11) are provided on the outside of both ends of the housing (1), and the clamps (11) have a reaction zone air inlet (7) for sending reaction gas into the reaction zone (5), a purge zone air inlet (8) for sending purge gas into the purge zone, a purge zone outlet (10) for sending purge gas out of the purge zone (6), and a reaction zone outlet (9) for sending post-reaction gas out of the reaction zone (5).
[0012] [2] The propane dehydrogenation membrane reactor based on a functional ceramic membrane according to [1], wherein the functional ceramic membrane (2) is composed of:
[0013] BE α X β O 3-δ
[0014] wherein X represents one or more elements selected from zirconium, yttrium, ytterbium, scandium, and iron; α is 0.70 to 0.99, and β is 0.01 to 0.30; and δ represents an oxygen vacancy.
[0015] [3]. The propane dehydrogenation membrane reactor based on a functional ceramic membrane according to [1] is characterized in that the current collector (3) is a silver paste, and the silver paste is connected to a silver wire.
[0016] [4] A propane dehydrogenation method, which uses the propane dehydrogenation membrane reactor based on the functional ceramic membrane described in any one of [1] to [3] to carry out propane dehydrogenation.
[0017] [5] The propane dehydrogenation method according to [4], comprising the following steps:
[0018] After preheating the raw material propane gas to 300-600°C, it is introduced into the reaction zone (5) from the reaction zone air inlet (7), and a purge gas containing oxygen components is introduced into the purge zone (6) from the purge zone air inlet (8). At the same time, a constant voltage is applied to the functional ceramic membrane.
[0019] In the reaction zone, propane reacts under the action of the catalyst (4) to generate propylene and hydrogen, and the propylene is discharged from the reaction zone outlet (10), and the hydrogen is adsorbed and dissociated into protons on the surface of the functional ceramic membrane (2) and then transmitted to the purge zone (6) through the functional ceramic membrane (2). In addition, the oxygen-containing components in the purge gas of the purge zone (6) are adsorbed and dissociated into oxygen ions on the surface of the functional ceramic membrane (2), wherein a part of the oxygen ions reacts with the protons transmitted to the purge zone (6) to generate water, and a part of the oxygen ions are transmitted through the functional ceramic membrane (2) into the reaction zone (5), react with the carbon deposited on the catalyst (4), and the generated carbon dioxide is discharged from the reaction zone outlet (10).
[0020] [6] The propane dehydrogenation method according to [5], wherein the constant voltage is in the range of 0.5V to 5V.
[0021] [7] The propane dehydrogenation method according to [5], wherein the raw propane gas is preheated to 400-600°C.
[0022] [8] The propane dehydrogenation method according to [5], wherein the purge gas is air or water vapor.
[0023] [9] The propane dehydrogenation method according to [8], wherein the purge gas is water vapor.
[0024]
[10] . Use of a propane dehydrogenation membrane reactor based on a functional ceramic membrane as described in any one of [1] to [3] in propane dehydrogenation.
[0025] The functional ceramic membrane-based propane dehydrogenation membrane reactor of the present invention has dual hydrogen and oxygen permeability, and can remove the reaction product hydrogen in-situ while the propane dehydrogenation reaction is being carried out, thereby improving the propane conversion rate; at the same time, the other side of the membrane can separate oxygen from the purge gas and transmit it to the reaction side, thereby achieving the purpose of eliminating and inhibiting carbon deposition. In addition, while the propane dehydrogenation reaction is being carried out, a constant voltage is applied to both sides of the membrane using a current collector, with the reaction zone side serving as the anode and the purge zone side serving as the cathode. Under electrical drive, the hydrogen in the reaction zone dissociates into protons and moves toward the cathode purge zone under the push of the anode; at the same time, the oxygen on the purge side dissociates into cations and moves toward the anode reaction zone under the push of the cathode, thereby achieving the counter-permeation of hydrogen and oxygen. BRIEF DESCRIPTION OF THE DRAWINGS
[0026] Figure 1Schematic diagram of the structure of a propane dehydrogenation membrane reactor based on functional ceramic membrane.
[0027] Figure 2 FIG1 is a schematic diagram of a propane dehydrogenation reaction performed in a propane dehydrogenation method according to an embodiment.
[0028] Among them, 1. Shell; 2. Functional ceramic membrane; 3. Current collector; 4. Catalyst; 5. Reaction zone; 6. Purge zone; 7. Reaction zone air inlet; 8. Purge zone air inlet; 9. Purge zone air outlet; 10. Reaction zone air outlet; 11. Clamp. DETAILED DESCRIPTION
[0029] For a better understanding of the present invention, the present invention is further described in detail below with reference to the accompanying drawings and embodiments thereof. However, the scope of protection claimed by the present invention is not limited to the scope shown in the embodiments.
[0030] The propane dehydrogenation membrane reactor based on the functional ceramic membrane includes a shell and a functional ceramic membrane. Both ends of the shell are closed by external clamps, and both ends of the functional ceramic membrane are open. The shell and the functional ceramic membrane are both tubular, and the functional ceramic membrane is located inside the shell.
[0031] The area between the functional ceramic membrane and the shell forms a reaction zone, and the reaction zone is located in the middle of the functional ceramic membrane and is loaded with a catalyst.
[0032] A purge zone is formed inside the functional ceramic membrane, and current collectors are attached to the inner and outer surfaces of the functional ceramic membrane.
[0033] Clamps are provided on the outside of both ends of the aforementioned shell, and the aforementioned clamps have a reaction zone air inlet for sending the reaction gas into the reaction zone, a purge zone air inlet for sending the purge gas into the purge zone, a purge zone outlet for sending the purge gas out of the purge zone, and a reaction zone outlet for sending the post-reaction gas out of the reaction zone.
[0034] The functional ceramic membrane is in a tubular shape. Such a functional ceramic membrane may be a tubular membrane or a hollow fiber membrane.
[0035] In some preferred embodiments, the functional ceramic membrane may be composed of:
[0036] BE α X β O 3-δ
[0037] wherein X represents one or more elements selected from zirconium, yttrium, ytterbium, scandium, and iron; α is 0.70 to 0.99, and β is 0.01 to 0.30; and δ represents an oxygen vacancy.
[0038] The functional ceramic membrane composed above is a perovskite material, which has mixed proton / oxygen ion conduction properties under high temperature conditions. Therefore, the functional ceramic membrane has selective hydrogen and oxygen permeability at high temperatures, while other gases such as propane, propylene, methane, ethane, and ethylene cannot penetrate, thereby achieving selective permeation of only hydrogen and oxygen.
[0039] In a preferred embodiment, the composition of the functional ceramic membrane is BaCe 0.7 Zr 0.1 Y 0.1 Yb 0.1 O 3-δ , where δ is an oxygen vacancy.
[0040] In some preferred embodiments, the current collector is silver paste, which is connected to the silver wire. In some preferred embodiments, the functional ceramic membrane-based propane dehydrogenation membrane reactor is further provided with a temperature control heating device outside the housing for heating the reaction zone.
[0041] Figure 1 FIG. 1 shows a propane dehydrogenation membrane reactor based on a functional ceramic membrane according to an embodiment of the present invention. Figure 1 As shown, the device includes a housing 1 and a functional ceramic membrane 2. The housing 1 is closed at both ends by external clamps, and the functional ceramic membrane 2 is open at both ends. The housing 1 and the functional ceramic membrane 2 are both tubular, and the functional ceramic membrane 2 is located inside the housing 1.
[0042] The area between the functional ceramic membrane 2 and the housing 1 forms a reaction zone 5. The reaction zone 5 is located in the middle of the functional ceramic membrane 2 and is loaded with a catalyst 4.
[0043] A purge zone 6 is formed inside the functional ceramic membrane 2, and a current collector 3 is attached to the inner and outer surfaces of the functional ceramic membrane 2.
[0044] Clamps 11 are provided on the outside of both ends of the shell 1. The clamps 11 are used for sending in and out of gas. The clamps 11 have a reaction zone air inlet 7 for sending the reaction gas into the reaction zone 5, a purge zone air inlet 8 for sending the purge gas into the purge zone 6, a purge zone outlet 10 for sending the purge gas from the purge zone 6, and a reaction zone outlet 9 for sending the post-reaction gas from the reaction zone 5.
[0045] Figure 2 The schematic diagram of FIG1 shows a schematic diagram of a propane dehydrogenation method according to an embodiment of the present invention. In this method, the propane dehydrogenation reaction is carried out using the aforementioned propane dehydrogenation membrane reactor.
[0046] The aforementioned propane dehydrogenation membrane reactor based on functional ceramic membrane can apply a constant voltage on both sides of the membrane using a current collector during the propane dehydrogenation reaction. The reaction zone side is the anode and the purge zone side is the cathode. Under electric drive, the hydrogen in the reaction zone dissociates into protons and moves toward the cathode purge zone under the push of the anode; at the same time, the oxygen in the purge side dissociates into cations and moves toward the anode reaction zone under the push of the cathode, thereby realizing the counter-permeation of hydrogen and oxygen.
[0047] The aforementioned catalyst may be a conventional catalyst used in the propane dehydrogenation process, for example, a chromium oxide catalyst. Examples of such catalysts include Cr-2010 chromium oxide catalysts with a model number of BSAF.
[0048] The aforementioned catalyst is preferably placed in the reaction zone via a stacking method. This allows for a more even distribution of gas within the catalyst bed. Compared to other loading methods, the stacked catalyst bed structure is relatively loose, resulting in less resistance to gas passage and, consequently, a lower pressure drop. The distribution of voids between catalyst particles is more rational, allowing the reactant gas to fully diffuse onto the surface of the catalyst particles, fully utilizing the catalyst's active sites and thereby improving catalyst utilization.
[0049] In some embodiments, the housing may be, for example, a stainless steel tube.
[0050] In some embodiments, the current collector may be a silver paste connected to a silver wire, preferably by applying a constant voltage thereto.
[0051] Preferably, the propane dehydrogenation membrane reactor is further provided with a temperature control heating device, which is used to heat the reactor to provide the temperature required for the propane dehydrogenation reaction.
[0052] The propane dehydrogenation method of the present invention uses the aforementioned propane dehydrogenation membrane reactor based on the functional ceramic membrane to carry out propane dehydrogenation.
[0053] In some embodiments, the aforementioned propane dehydrogenation method includes the following steps:
[0054] After preheating the raw material propane gas to 300-600°C, it is introduced into the reaction zone (5) from the reaction zone air inlet (7), and a purge gas containing oxygen components is introduced into the purge zone (6) from the purge zone air inlet (8). At the same time, a constant voltage is applied to the functional ceramic membrane.
[0055] In the reaction zone, propane reacts under the action of the catalyst (4) to generate propylene and hydrogen, and the propylene is discharged from the reaction zone outlet (10), and the hydrogen is adsorbed and dissociated into protons on the surface of the functional ceramic membrane (2), and then transmitted to the purge zone (6) through the functional ceramic membrane (2). In addition, the oxygen-containing components in the purge gas of the purge zone (6) are adsorbed and dissociated into oxygen ions on the surface of the functional ceramic membrane (2), wherein a part of the oxygen ions reacts with the protons transmitted to the purge zone (6) to generate water, and a part of the oxygen ions is transmitted through the functional ceramic membrane (2) into the reaction zone (5), and reacts with the carbon deposited on the catalyst (4) to generate carbon dioxide, which is discharged from the reaction zone outlet (10).
[0056] In the aforementioned propane dehydrogenation method, by instantaneously removing the reacting hydrogen during the propane reaction, the hydrogen content in the reaction zone is reduced, breaking the chemical equilibrium and shifting the reaction in the positive direction, thereby improving the propane conversion rate. Furthermore, by introducing an oxygen-containing component into the purge gas, the aforementioned propane dehydrogenation method effectively slows the rate of carbon deposition on the catalyst, extending the catalyst's service life and reducing the frequency of catalyst replacement and operating costs.
[0057] The aforementioned carbon deposits originate from side reactions during the dehydrogenation of propane to propylene, such as the direct cracking of propane at high temperatures to produce methane and coke. This coke accumulates on the catalyst surface, covering active sites and causing catalyst deactivation. By including oxygen-containing components in the purge gas, the oxygen ions formed after dissociation on the ceramic membrane surface can penetrate the membrane and enter the reaction zone. There, they react with carbon deposited on the catalyst supported on the membrane to produce carbon dioxide, thereby eliminating the carbon deposits on the catalyst.
[0058] Preferably, the aforementioned constant voltage is 0.5V to 5V. Applying this voltage to the functional ceramic membrane increases electron conductivity, increases the movement of protons toward the purge zone, allows more hydrogen to permeate, and increases hydrogen permeability at low temperatures. Applying this voltage to the functional ceramic membrane promotes the permeation of hydrogen and oxygen in opposite directions.
[0059] Preferably, the purge gas is air or water vapor. When air is used, oxygen in the air is adsorbed and dissociated into oxygen ions on the surface of the functional ceramic membrane; when water vapor is used, water vapor dissociates into hydrogen ions and oxygen ions on the functional ceramic membrane.
[0060] Preferably, the propane feed gas is preheated to 400-600° C., more preferably 500-600° C. This controls the reaction temperature to the catalyst's optimum reaction temperature, thereby increasing the reaction energy and promoting the reaction toward propylene production, thereby accelerating the reaction.
[0061] Example
[0062] Example 1
[0063] use Figure 1 The functional ceramic membrane reactor shown in the figure is used for propane dehydrogenation experiment, in which the functional ceramic membrane is composed of BaCe 0.7 Zr 0.1 Y 0.1 Yb 0.1 O 3-δ The catalyst is chromium oxide (BSAF Cr-2010), and a tubular furnace for heating is installed outside the reactor. The temperature is controlled to 550°C for propane dehydrogenation reaction. Propane is introduced into the reaction zone at a flow rate of 30 ml / min, and air is introduced into the purge zone at a flow rate of 20 ml / min. In addition, a digital source meter is used to apply a constant voltage of 1.5V to the two silver wires connected to the silver paste of the functional ceramic membrane. In the reaction zone, propane is decomposed into propylene and hydrogen under the action of the catalyst. The generated propylene is discharged from the outlet of the reaction zone, and the generated hydrogen is adsorbed and dissociated into protons on the outer surface of the functional ceramic membrane. The protons pass through the functional ceramic membrane from the reaction zone to the purge zone, reacting with some oxygen in the air to produce water. At the same time, the oxygen in the air in the purge zone is adsorbed and dissociated into oxygen ions on the inner surface of the functional ceramic membrane, which pass through the functional ceramic membrane from the purge zone to the reaction zone, participating in the propane dehydrogenation reaction in the reaction zone.
[0064] Example 2
[0065] The reaction temperature was raised to 600° C., and the other conditions remained unchanged. A propane dehydrogenation experiment was carried out in the same manner as in Example 1.
[0066] Example 3
[0067] The propane dehydrogenation experiment was carried out in the same manner as in Example 1, except that the purge gas was replaced by water vapor (with the same molar flow rate as the air in Example 1) and the other conditions remained unchanged.
[0068] Comparative Example 1
[0069] Only the shell of the propane dehydrogenation membrane reactor used in Example 1 was used, and the catalyst was directly deposited in the shell. The temperature was controlled to 550° C. for propane dehydrogenation reaction. Propane was introduced at a flow rate of 30 ml / min. Propane was decomposed into propylene and hydrogen under the action of the catalyst, and the generated propylene and hydrogen were discharged from the gas outlet.
[0070] Propane conversion rate and propylene selectivity detection
[0071] Gas chromatography was used to analyze the gas outlets after the propane dehydrogenation reactions in Examples 1-3 and the comparative example. The results showed that in Example 1, the propane conversion was 19.59% and the propylene selectivity was 83.48%. In Comparative Example 1, the propane conversion was 17.97% and the propylene selectivity was 82.19%. In Example 2, the propane conversion was 36.80% and the propylene selectivity was 79.52%. In Example 3, the propane conversion was 21.61% and the propylene selectivity was 85.58%.
[0072] In addition, the rate of decrease in propane conversion was measured. The results showed that the propane conversion of Example 1 decreased from 26.7% to 14.9% within 12 hours, and that of Example 2 decreased from 31% to 21% within 12 hours. The propane conversion of Example 3 decreased from 26.7% to 19% within 12 hours, and that of Comparative Example 1 decreased from 26% to 6.2% within 12 hours. Compared to Comparative Example 1, the rate of decrease in propane conversion in Example 1 was significantly lower, indirectly indicating that the presence of oxygen reduced carbon deposition on the catalyst.
[0073] Carbon deposit detection
[0074] The catalysts were weighed by TGA after the reaction. The carbon deposition rates of the catalysts in Examples 1 to 3 were 18.83%, 16.10%, and 15.04%, respectively, while the carbon deposition rate of the catalyst in Comparative Example 1 was 25.04%, indicating that oxygen permeation effectively reduced the carbon residue on the catalyst surface.
Claims
1. A propane dehydrogenation membrane reactor based on functional ceramic membrane, characterized in that: The invention comprises a housing (1), a propane dehydrogenation catalyst, and a functional ceramic membrane (2); the housing (1) is closed by external clamps (11) at both ends, and the functional ceramic membrane (2) is open at both ends; the housing (1) and the functional ceramic membrane (2) are both tubular; and the functional ceramic membrane (2) is located inside the housing (1). The area between the functional ceramic membrane (2) and the housing (1) forms a reaction zone (5), and the reaction zone (5) is located in the middle of the functional ceramic membrane (2) and is loaded with a propane dehydrogenation catalyst (4). A purge zone (6) is formed inside the functional ceramic membrane (2), and current collectors (3) are attached to the inner and outer surfaces of the functional ceramic membrane (2). Clamps (11) are provided on the outside of both ends of the housing (1), and the clamps (11) have a reaction zone air inlet (7) for sending reaction gas into the reaction zone (5), a purge zone air inlet (8) for sending purge gas into the purge zone, a purge zone outlet (10) for sending purge gas out of the purge zone (6), and a reaction zone outlet (9) for sending post-reaction gas out of the reaction zone (5).
2. The propane dehydrogenation membrane reactor based on functional ceramic membrane according to claim 1, characterized in that: The functional ceramic membrane (2) is composed of: Not present α X β BOTANY 3-δ wherein X represents one or more elements selected from zirconium, yttrium, ytterbium, scandium, and iron; α is 0.70 to 0.99, β is 0.01 to 0.30, and δ represents an oxygen vacancy.
3. The propane dehydrogenation membrane reactor based on functional ceramic membrane according to claim 1, characterized in that: The current collector (3) is silver paste, and the silver paste is connected to the silver wire.
4. A propane dehydrogenation method, characterized in that: Propane dehydrogenation is carried out using the propane dehydrogenation membrane reactor based on the functional ceramic membrane according to any one of claims 1 to 3.
5. The propane dehydrogenation method according to claim 4, characterized in that The propane dehydrogenation method comprises the following steps: After preheating the raw material propane gas to 300-600°C, it is introduced into the reaction zone (5) from the reaction zone air inlet (7), and a purge gas containing oxygen components is introduced into the purge zone (6) from the purge zone air inlet (8). At the same time, a constant voltage is applied to the functional ceramic membrane. In the reaction zone, propane reacts under the action of the catalyst (4) to generate propylene and hydrogen, and the propylene is discharged from the reaction zone outlet (10). The hydrogen is adsorbed and dissociated into protons on the surface of the functional ceramic membrane (2) and then transmitted to the purge zone (6) through the functional ceramic membrane (2). In addition, the oxygen-containing components in the purge gas of the purge zone (6) are adsorbed and dissociated into oxygen ions on the surface of the functional ceramic membrane (2), wherein a part of the oxygen ions reacts with the protons transmitted to the purge zone (6) to generate water, and a part of the oxygen ions are transmitted through the functional ceramic membrane (2) into the reaction zone (5), react with the carbon deposited on the catalyst (4), and generate carbon dioxide, which is discharged from the reaction zone outlet (10).
6. The propane dehydrogenation method according to claim 5, characterized in that The constant voltage is in the range of 0.5V to 5V.
7. The propane dehydrogenation method according to claim 5, characterized in that The raw material propane gas is preheated to 400-600°C.
8. The propane dehydrogenation method according to claim 5, characterized in that The purge gas is air or water vapor.
9. The propane dehydrogenation method according to claim 8, characterized in that The purge gas is water vapor.
10. Use of the propane dehydrogenation membrane reactor based on a functional ceramic membrane according to any one of claims 1 to 3 in propane dehydrogenation.