Co-thermal coupling of carbonate decomposition and propane dehydrogenation via hydrogen transfer

Strongly endothermic reactions are always constrained by thermodynamic equilibrium that necessitates high-temperature operation. This paper describes a co-thermal coupling strategy that integrates two thermodynamic equilibrium-limited processes into a single reaction environment via hydrogen transfer. In this system, the hydrogen generated in situ from endothermic propane dehydrogenation is continuously consumed by simultaneous carbonate decomposition, thereby achieving bidirectional reaction intensification. As a result, the decomposition temperature of calcium carbonate is reduced by approximately 75 °C compared to inert conditions, while the propane dehydrogenation conversion reaches ~120% of the thermodynamic equilibrium value with a propylene selectivity of 97.8% during the continuous regeneration cycles. In situ spectroscopic and kinetic analyses demonstrate a coupled reaction network, where hydrogen transfer promotes carbonate transformation via bicarbonate-related surface intermediates and then follows the reverse water-gas shift pathway. Techno-environmental analysis indicates that this integrated process lowers the energy consumption per ton of propylene by 9.8% and reduces net CO2 emissions by 18.1% in the base-case industrial simulation, while co-producing propylene and a CaO-containing solid. These findings establish hydrogen-mediated co-thermal coupling as a general strategy for surmounting equilibrium constraints and intensifying energy- and carbon-intensive chemical processes. Thermodynamic equilibrium imposes a major limitation on strong endothermic reactions, requiring energy-intensive high-temperature operation. Here, the authors develop a co-thermal coupling strategy that links two equilibrium-limited processes through hydrogen transfer in a single reaction environment, achieving bidirectional reaction intensification.