Biorefinery Systems Engineering: From Facility Location to Process Synthesis and Design

Abstract

This thesis applies concepts, tools and techniques of Process Systems Engineering to problems arising from the conversion of biomass to fuel and chemical products. Waste grease produced in metropolitan areas needs to be treated before it can be disposed. One option is to convert it to biodiesel for resale to the local population. The optimal locations of small-scale facilities for this conversion within Greater London is studied. The technical and economic performance criteria of a small scale facility are initially determined. These are then used in the formulation of an optimization problem that finds the best locations of these small scale production facilities within Greater London such that delivery times and resource utilization are optimized. Biorefineries have been identified as a promising alternative to crude oil refineries for the production of fuels and chemicals. Biorefineries convert renewable biomass resources using multiple chemical and physical transformations. Process synthesis is the optimal, according to a specific objective function, selection and arrangement of processing units. A systematic biorefinery process synthesis problem is formulated for finding which products and processes result in a biorefinery with the highest economic potential or carbon efficiency. Membrane based technologies are capable of efficiently tackling separation processes that remain challenging for traditional distillation. A hollow-fiber supported zeolite membrane technology is initially modelled. Techno-economic analyses of the feasibility of these membranes applied to the dehydration of ethanol and the separation of butane isomers are then performed. Finally, the standard pressure-driven flux membrane models previously used are extended to include a mathematical description of adsorption-diffusion based flux. This allows for flux to be predicted directly from operating conditions such as pressures and temperatures rather than relying on fixed values of permeance and selectivity to predict flux through the membrane layer. A comparison of a pressure-driven flux model with this novel adsorption- diffusion model for butane isomer separation is performed.