Synthesis of augmented biofuel processes using solar energy

Abstract

A method for synthesizing augmented biofuel processes, which improve biomass carbon conversion to liquid fuel (g carbon ) using supplemental solar energy as heat, H 2 , and electricity is presented. For a target g carbon , our method identifies augmented processes requiring the least solar energy input. A nonconvex mixed integer nonlinear programming model allowing for simultaneous mass, heat, and power integration, is built over a process superstructure and solved using global optimization tools. As a case study, biomass thermochemical conversion via gasification/Fischer-Tropsch synthesis and fast-hydropyrolysis/hydrodeoxygenation (HDO) is considered. The optimal process configurations can be categorized either as standalone (g carbon 54%), augmented using solar heat (54% g carbon 74%), or augmented using solar heat and H 2 (74 g carbon 95%). Importantly, the process H 2 consumption is found to be close to the derived theoretical minimum values. To accommodate for the intermittency of solar heat/H 2 , we suggest processes that can operate at low and high g carbon .All the flow rates are normalized to 1 kmol/h of biomass carbon feed processed. Multiple values (separated by commas) considered for certain parameters.

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