Process Synthesis with Heat and Power Integration of Thermochemical Coal, Biomass, and Natural Gas Hybrid Energy Processes

Abstract

Abstract A thermochemical based process superstructure was created to consider various process alternatives to convert biomass, coal, and natural gas to liquid (CBGTL) transportation fuels. Using binary variables to model process decisions and constraints to model mass and energy conservation, phase and chemical equilibrium, and process stream splitting, a mixed-integer non-linear optimization model is developed to determine the topology of the CBGTL refinery that produced the lowest-cost fuels. The mathematical model includes a simultaneous heat and power integration which uses a series of heat engines to recover electricity from the process waste heat. Using herbaceous biomass (switchgrass), low-volatile bituminous coal, and natural gas, two case studies are presented to investigate the effect of CO 2 sequestration and greenhouse gas reduction targets on the CBGTL process topology.