Catalytic dehydrogenation of alkanes: Industrial progress and future prospects
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Catalytic dehydrogenation of alkanes: Industrial progress and future prospects. Catalytic dehydrogenation of alkanes is an important process for producing light olefins such as propylene and isobutylene, and its industrial significance has become increasingly prominent, especially given the continuous rise in demand for propylene. I. Technical Background and Market Drivers Light olefins are key raw materials in the chemical industry chain; by 2025, the global production capacity for ethylene is expected to be around 230 million tons, while that for propylene will be around 188 million tons. Although traditional steam cracking and catalytic cracking (FCC) are the main sources, their propylene/ethylene yield ratio is limited (around 0.6–0.7), making it difficult to meet the growing demand for propylene. Alkane dehydrogenation (especially propane dehydrogenation) has become a key technology to fill the supply-demand gap. II. Technical Parameters 1. Thermodynamic and reaction conditions Temperature: Propane dehydrogenation must take place at 550–700°C to achieve an equilibrium conversion rate of 30–50% ； The isobutane dehydrogenation temperature can be slightly lower (about 500–550°C). While high temperatures are favorable for thermodynamic equilibrium, they can also trigger side reactions such as cracking and coking. Pressure: Reducing the partial pressure of alkanes can shift the equilibrium toward olefins. In industry, negative pressure operation (such as the CATOFIN process, at around 0.5–0.6 bar) or steam dilution (such as the STAR process, with a steam/alkane molar ratio ≥3) is employed to achieve efficient conversion. Hydrogen removal: Hydrogen is removed through selective hydrogen combustion (SHC) or oxidative dehydrogenation (ODH), which allows overcoming thermodynamic limitations and increasing the one-pass conversion rate. Pressure: Reducing the partial pressure of alkanes can shift the equilibrium toward olefins. In industry, negative pressure operation (such as the CATOFIN process, at around 0.5–0.6 bar) or steam dilution (such as the STAR process, with a steam/alkane molar ratio ≥3) is employed to achieve efficient conversion. Hydrogen removal: Hydrogen is removed through selective hydrogen combustion (SHC) or oxidative dehydrogenation (ODH), which allows overcoming thermodynamic limitations and increasing the one-pass conversion rate.
III. Technical Advantages and Challenges ✅ Advantages: • High selectivity: The platinum-tin catalyst achieves an acrylene selectivity of 89–91%, and an isobutylene selectivity of 91–93%. •Flexible process: can be adapted to various feedstocks such as propane, isobutane, and n-butane. •Low by-products: Dilution with steam or hydrogen effectively suppresses cracking and hydrolysis reactions. •Advanced industrialization: Processes such as Oleflex and CATOFIN have been in use for decades, with plants located around the world. ❌ Challenges: • Catalyst deactivation: Coking leads to a decrease in activity, requiring frequent regeneration which affects continuous operation. •High energy consumption: The reaction is highly endothermic, requiring substantial heat input or complex heat integration. •High investment costs: Platinum-based catalysts are expensive, and high standards are required for the material of reactors. •Safety: High temperatures, flammable atmospheres, and oxygen introduction (SHC) increase operational risks. IV. Directions for Improvement 1. Catalysts: Low-platinum/non-platinum catalysts: Develop highly dispersed and stable low-platinum alloy or non-precious metal (such as Fe, Co-based) catalysts. In 2025, Runhe Catalyst Co., Ltd. announced that its independently developed chromium-based fixed-bed propane dehydrogenation catalyst had achieved its first domestic industrial application, operating stably in a plant with a capacity of 500,000 tons per year for over a year ； Zhejiang University, in collaboration with the Dalian Institute of Chemical Physics of the Chinese Academy of Sciences and other institutions, has successfully developed a cobalt-based zeolite catalyst (CoS-1). This catalyst achieves an acrylene selectivity of 92% and can operate stably for 240 hours under non-hydrogen conditions; its overall performance exceeds that of traditional platinum-based catalysts, offering a new approach for further reducing costs in the future ； The performance of the Pt-based catalysts developed by the Dalian Institute of Chemical Physics, Chinese Academy of Sciences, has reached or surpassed the levels of foreign manufacturers such as UOP, making them capable of replacing imported catalysts. Carrier optimization: Development of new carriers with high specific surface area and high thermal stability (such as mesoporous oxides and carbon materials). Anti-coking design: Delay the accumulation of coking through surface alkaline modification or the creation of “carbon migration” pathways.
2. Process integration and enhancement – Membrane reactors: Pd-based or ceramic membranes are used for the selective separation of hydrogen, thereby increasing the conversion rate (a conversion rate increase of >20% has been achieved in laboratory tests). CO₂-assisted dehydrogenation: Using CO₂ as a mild oxidant reduces the alkane partial pressure and simultaneously consumes hydrogen through the reverse water-gas reaction, thereby increasing the equilibrium conversion rate. Oxidative dehydrogenation (ODH): Developing highly selective and long-lasting ODH catalysts to achieve efficient conversion at low temperatures. 3. Energy optimization – Waste heat recovery: Utilizing recycled flue gas or the residual heat from products to preheat the feed, thereby reducing energy consumption. Electroheated catalysis: Exploring the use of electric heat to directly heat the catalyst bed, enabling rapid response and precise temperature control. 4. Digitalization and intelligent control via AI optimization: Real-time adjustment of temperature, air velocity, and dilution ratio based on big data and machine learning to maximize selectivity and catalyst lifespan. Online monitoring: In-situ techniques such as Raman and mass spectrometry are used to monitor the catalyst status and product distribution. V. Conclusion Alkane catalytic dehydrogenation technology has become an indispensable part of the propylene supply chain. With continuous advancements in catalyst materials, reactor design, and process integration technologies, their economic efficiency and environmental friendliness will further improve. In the future, by integrating innovative approaches such as membrane separation, CO₂ utilization, and intelligent control, alkane dehydrogenation is expected to play a more important role in the transition toward a low-carbon chemical industry. (Note: Some content has been organized by AI)
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