Conceptual design and techno-economic analysis of a novel propane dehydrogenation process integrated with chemical looping combustion and CO2 hydrogenation

Abstract

Propane dehydrogenation is a promising propylene production technology since it can alleviate its dependence on oil resources. However, the propane-to-propylene process will produce a large amount of hydrogen and hydrocarbons, which will not only waste energy, but also lead to CO2 emissions if they are directly burned for heating. In order to address these problems, this study proposes a novel propylene and methanol production process from propane, in which the hydrogen in the product gas is firstly extracted by pressure swing adsorption, then the remaining hydrocarbons are subjected to chemical looping combustion to provide heat and high purity CO2, and the hydrogen and CO2 are finally reacted into methanol. The exergy efficiency of the novel process is increased from 77.61% of the base process to 80.18% with about 98% of direct CO2 capture and about 40% of CO2 utilization. The fixed capital investment and total product cost & gross earnings cost of the novel process are 4200 million RMB and 3893 million RMB/y, 8.11% and 5.27% higher than those of the base process caused by additional costs of new units and power consumption, while its annual profit is 14 million RMB/y higher than the base process due to the extra methanol income. The study concludes that the novel process is superior in exergy efficiency and CO2 capture & utilization, but inferior in high capital investment.