Process integration, economic and environmental analysis tools for biorefinery design

Abstract

Process integration, economic and environmental analysis tools for biorefinery designRenewability and the carbonaceous basis of biomass provide potential for both energy and chemical production in biorefineries in a fashion similar to crude oil refineries. Biorefineries are envisaged as having a key role in the transition to a more sustainable industry, especially as a means to mitigate greenhouse gas (GHG) emissions. A biorefinery is a concept for the flexible, efficient, cost-effective and sustainable conversion of biomass through a combination of process technologies into multiple products. This implies that biorefineries must be integrated through designs that exploit the interactions between material and energy streams.The wide range of possibilities for biomass feedstock, processes and products poses a challenge to biorefinery design. Integrating biorefineries within evolving economic and environmental policy contexts requires careful analysis of the configurations to be deployed from early in the design stage. This research therefore focuses on the application and development of methodologies for biorefinery design encompassing process integration tools, economic and environmental sustainability analyses together. The research is presented in the form of papers published or submitted to relevant peer-reviewed journals, with a preamble for each paper and a final synthesis of the work as a whole.In a first stage, mass pinch analysis was adapted into a method for integration of biorefineries producing bioethanol as a final product and also utilising bioethanol as a working fluid within the biorefinery. The tool allows targeting minimum bioethanol utilisation and assessing network modifications to diminish revenue losses. This new application could stimulate the emergence of similar approaches for the design of integrated biorefineries. The thesis then moves to combine feedstock production models, process simulations in Aspen Plus® and process integration with LCA, to improve energy efficiency and reduce GHG emissions of biorefineries. This work, presented via two publications covering wheat to bioethanol and Jatropha to biodiesel or green diesel, provided evidence of the benefits of biorefinery integration for energy saving and climate change adaptation. The multilevel modelling approach is then further integrated into a methodology developed for the combined evaluation of the economic potential and GHG emissions saving of a biorefinery from the marginal performances of biorefinery products. The tool allows assessing process integration pathways and targeting for policy compliance. The tool is presented via two further publications, the first drawing analogies between value analysis and environmental impact analysis in order to create the combined Economic Value and Environmental Impact (EVEI) analysis methodology, the second extending this to demonstrate how the tool can guide judicious movement of environmental burdens to meet policy targets.The research embodied in this thesis forms a systematic basis for the analysis and generation of biorefinery process designs for enhanced sustainability. The tools presented will facilitate both the implementation of integrated biorefinery designs and the cultivation of a community of biorefinery engineers for whom such integrated thinking is their distinctive and defining attribute.

Date of Award	31 Dec 2013
Original language	English
Awarding Institution	The University of Manchester
Supervisor	Grant Campbell (Supervisor)