Biomass and Natural Gas to Liquid Transportation Fuels and Olefins (BGTL+C2_C4): Process Synthesis and Global Optimization

This paper introduces a process synthesis and a global optimization framework toward the coproduction of liquid fuels and olefins from biomass and natural gas. A superstructure of alternatives is developed at each stage of the process with different gasification options, natural gas conversion routes, hydrocarbon production, and upgrading methods. Simultaneous heat, power, and water integration is introduced for the optimal usage of the utilities in the proposed plants. The global optimization framework with a branch-and-bound approach is utilized to determine the optimal process out of numerous alternatives that would give the maximum plant profit. The optimal topologies obtained suggest that the best possible process depends on the liquid fuels and olefins to be produced. Parametric analysis on different chemicals production levels suggests that both the profit and net present value (NPV) increases substantially at higher chemicals production levels. Economies of scale are present as the case studies at higher capacities result in higher profits and higher net present values. The results suggest that the proposed refineries with coproduction of liquid fuels and olefins are economically viable because of their high and positive NPVs. Furthermore, higher olefins production levels can make the plants more favorable economically.