Process optimization, exergy efficiency, and life cycle energy consumption-GHG emissions of the propane-to-propylene with/without hydrogen production process

Abstract

Propylene is an extreme important intermediate chemical and it is traditionally produced by steam cracking and fluid catalytic cracking of light oil in petrochemical plants, which will be gradually limited by the increasingly scare oil resources. The propylene production from propane is promising and expected to significantly reduce oil consumption. The process modeling and system analysis methods are used to investigate the techno-environmental performance of the propane dehydrogenation processes with poly-generation of propylene and hydrogen. The propane dehydrogenation processes have great energetic and environmental competitiveness compared with the coal-to-propylene. The propane consumption and direct CO2 emissions are only 1.19 t/t C3H6 and 415 kg/t C3H6. The exergy efficiency of the propane dehydrogenation process with no H2 production is calculated to be 77.61%, while that are as high as 78.68% and 80.73% for the propane dehydrogenation process with H2 recovery rates of 90% and 95%. After subtracting the hydrogen production part, the life cycle energy consumption and GHG emissions of 1 t propylene for the process with H2 recovery rate of 95% are 2.72% and 3.97% lower than that the process with no hydrogen production. This study confirms that development of propane-based propylene and hydrogen production is energetic and environmentally competitive and is therefore promising in olefins industry.