Conversion of CO2-Rich Natural Gas to Liquid Transportation Fuels via Trireforming and Fischer-Tropsch Synthesis: Model-Based Assessment

Abstract

This paper presents a model-based analysis of a process coupling trireforming and Fischer–Tropsch technologies for the production of liquid fuels from CO2-rich natural gas. The process also includes an upgrading section based on hydrocracking, a separation section, a water gas shift unit, and a Rankine cycle unit for recovering the excess thermal energy produced by the Fischer–Tropsch reactor. Simulations are carried out in the process simulator Aspen Plus using standard unit operation models where applicable, while modeling the nonconventional units, such as the Fischer–Tropsch and hydrocracking reactors, using Aspen Custom Modeler. The proposed process could achieve a carbon conversion efficiency upward of 50% in the analyzed scenario, despite a natural gas feedstock with 30 mol % CO2. The analysis also reveals that the plant-wide electricity consumption could be covered nearly entirely by the Rankine cycle unit, enabling significant cost savings alongside a reduction of the overall global warming potential by about 10% in this specific case study. Finally, the results of a detailed economic assessment indicate that cheap natural gas is a prerequisite to the economic viability of the process, which would remain attractive in the current US scenario, yet presents a major impediment for its deployment in Brazil.