Development of Integrated High Temperature and Low Temperature Fischer-Tropsch System for High Value Chemicals Coproduction

Abstract

The conventional indirect coal-to-liquids process for transportation fuel production suffers from inefficiency in syncrude utilization and poor economic performance. This is largely because the FT syncrude are not properly used. In consideration of the potential synergies in fuel quality improvement and chemicals coproduction, for further high value utilization of the hydrocarbon products, the novel HTFT-LTFT system integrated high temperature Fischer-Tropsch process and low temperature Fischer-Tropsch process together is proposed based on the advanced coal gasification and FT techniques and modelled in Aspen Plus. Energy, exergy analysis and a detailed economic analysis are performed. The synergies of the integrated system is also discussed by comparing with the separated HTFT/LTFT system. Results show that the integrated HTFT-LTFT systems can increase the annual income by more than 10% by high utilization of FT syncrude and reduce the capital investment by 18.2% by sharing infrastructure. Higher energy and exergy efficiencies as well as internal rate of return (IRR) are achieved by the integrated systems. The integrated HTFT-LTFT system is more efficiently and economically than the separated HTFT/LTFT system. Therein the integrated HTFT-LTFT system coproduce both olefins and base oils simultaneously presents an excellent economic performance with IRR of 18%, much higher than the 4.7% of the separated HTFT/LTFT system.