System development of integrated high temperature and low temperature Fischer–Tropsch synthesis for high value chemicals

Abstract

The conventional indirect coal-to-liquid process suffers from improperly utilization of Fischer–Tropsch (FT) syncrude and poor economic performance. In consideration of the potential synergies in the process and product integration from the high temperature Fischer–Tropsch (HTFT) and the low temperature Fischer–Tropsch technology (LTFT), the novel HTFT–LTFT system integrated HTFT and LTFT synthesis is proposed based on the advanced coal gasification and FT techniques to improve efficiency and add products value. The HTFT–LTFT system is firstly modelled in Aspen Plus platform and then evaluated by the energy, exergy, and detailed economic analysis. The synergies of the integrated system are discussed by comparing with the separate HTFT or LTFT system. Results show that the integrated HTFT–LTFT system is efficiently and economically superior to the separate HTFT or LTFT system, which reduces the capital investment by 18.2% and increases the annual income by more than 10%. The integrated HTFT–LTFT system with the coproduction of olefins and base oil simultaneously presents the IRR of 15.2% and has high ability against product prices fluctuation.