Decarbonised Polygeneration from Fossil and Biomass Resources

Abstract

Utilisation of biomass resources and CO2 abatement systems in currentlyexploited fossil resource based energy systems are the key strategies in resolving energysustainability issue and combating against global climate change. These strategies areaffected by high energy penalty and high investment. Therefore, it is imperative toassess the viability of these energy systems and further identify niche problem areasassociated with energy efficiency and economic performance improvement. The current research work has two parts. The first part presents techno-economic investigation of thermochemical conversion of biomass into the production of fuels (Fischer-Tropsch liquid or methanol) and electricity. The work encompasses centralised bio-oil integrated gasification plant, assuming that the bio-oil is supplied from distributed pyrolysis plant. Bio-oil is a high energy density liquid derived from biomass fast pyrolysis process, providing advantages in transport and storage. Various bio-oil based integrated gasification system configurations were studied. The configurations were varied based on oxygen supply units, once-through and full conversion configurations and a range of capacities from small to large scale. The second part of this thesis considers integration of various CO2 abatement strategies in coal integrated gasification systems. The CO2 abatement strategies under consideration include CO2 capture and storage, CO2 capture and reuse as well as CO2 reuse from flue gas. These facilities are integrated into cogeneration or polygeneration systems. The cogeneration concept refers to the production of combined heat and power while polygeneration concept is an integrated system converting one or more feedstocks into three or more products. Polygeneration is advocated in this work attributed to its high efficiency and lower emission. Furthermore, it can generate a balanced set of products consisting of fuels, electricity and chemicals. It is regarded as a promising way of addressing the future rapidly growing energy demands. A holistic approach using systematic analytical frameworks comprisingsimulation modelling, process integration and economic analysis has been developedand adopted consistently throughout the study for the techno-economic performanceevaluation of decarbonised fossil and bio-oil based systems. Important designmethodology, sensitivity analysis of process parameters and process systemmodifications are proposed. These are to enhance the efficiency as well as lower theeconomic and environmental impacts of polygeneration systems. A shortcutmethodology has also been developed as a decision-making tool for effective selectionfrom a portfolio of CO2 abatement options and integrated systems. Critical andcomprehensive analyses of all the systems under considerations are presented. Theseembrace the impact of carbon tax, product price evaluation and recommendations forsustainability of low carbon energy systems.

Date of Award	31 Dec 2011
Original language	English
Awarding Institution	The University of Manchester
Supervisor	Jhuma Sadhukhan (Supervisor)