Process Design and Optimization of an Integrated Shale Gas Process for Green Chemicals Production

This paper is concerned with the process design and optimization of an integrated shale gas process for greener chemicals production. From a sustainability point of view, the bioethanol is incorporated as a renewable feedstock to reduce the environmental footprint of the entire process. The proposed process integrates co-cracking of light NGLs, the oxidative coupling of methane (OCM) reaction, and bioethanol dehydration with raw shale gas processing. Overall, the process consists of four process areas, namely gas treatment, gas to chemicals, methane to ethylene and bioethanol to ethylene. A simulation-optimization method based on the NSGA-II algorithm is developed for the life cycle optimization of the process modelled in HYSYS. An energy integration model is also integrated using the mixed-integer linear programming. The results show that for a "good choice" design, the minimum ethylene selling price is $877.2/ton and the unit GWP of ethylene (GWP(E2E)) is 0.360 kg CO2-eq/kg, when shale gas is considered as a high carbon fuel.