(418b) Optimization of a Hybrid Biomass and Gas to Liquids Process Via Fischer–Tropsch Synthesis with Integrated Product Refining

The production of liquid transportation fuels still relies heavily on nonrenewable resources like petroleum. To address environmental challenges and ensure sustainable development, it is necessary to investigate alternative processes for liquid fuels production. Biomass as a renewable energy source is an attractive alternative feedstock since it could reduce greenhouse gas (GHG) emissions during photosynthesis. In order to avoid potential influence on the food market, the usage of nonfood-based biomass is necessary. However, biomass route requires large amount of capital investment because of the gasification and cleanup processes. Incorporation of additional carbon-based feedstocks like natural/shale gas as raw material could contribute to the reduction of capital cost.

A process synthesis framework for the production of liquid fuels from biomass and natural gas is introduced. The main challenges associated with BGTL processes are the high capital investment and uncertainties in product prices. The hydrocarbon products consist of gasoline, diesel and kerosene produced from syngas obtained from biomass gasification and natural gas reforming via Fischer–Tropsch synthesis and further upgrading process. The conceptual design of the process and its feasibility is tested in AspenPlus, along with the validation of thermodynamic models. The mathematical model and global optimization are implemented in PYOMO.

We consider simultaneous heat, power, and water integration. Heat is extracted through combustion of light gases obtained from the process. Electricity is produced via gas turbine engine. Excess water from the process is electrolyzed to produce H₂ and O₂. An optimization model is implemented to determine optimal process configuration at minimal total cost. The number and existence of some units, like separators for Claus process, air separation unit for O₂ production are determined and environmental considerations for GHG emission are met by CO₂ recycling and sequestration.