Packed bed combustion of biomass/liquid mixture combustion

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This proposal comprises two separate themes, both focussed on combustion of solid and liquid bio-fuels.1. Packed Bed Combustion of Biomass Fuels: Wood and other solid biomass fuels are becoming increasingly attractive as "carbon neutral" energy resources. The packed bed - relatively large pieces of fuel on a grate, with air admission from below - is the most common means of burning or gasifying these fuels, but because of its complexity it is less well understood than most other combustion processes. This proposal continues the development of computational models for the grate combustion of wood and other biomass fuels and the testing of these models by experiments, with the overall objective of providing numerical tools for design and operation. The models and knowledge developed will support the use of wood wastes and other solid biomass as energy resources; they will also be highly relevant to the closely related process of trash incineration.2. Liquid Mixture Combustion: A wide range of liquid biofuels is currently available or under development, including alcohols, biodiesel, and biomass pyrolysis oil ("bio-oil") made from wood, agricultural wastes, and other feedstocks. Design and operation of combustors and engines using these fuels requires detailed computational models of their evaporation and combustion behaviour as droplets and sprays. However, most liquid bio-fuels are complex mixtures with hundreds of different components, far too many to model individually in computer simulations. This project continues work on the "continuous thermodynamics" technique of representing complex mixtures by probability density functions instead of individual species, which allows models for liquid droplet combustion to simulate the chemical composition and distillation behaviour of fuels without excessive computation. The proposal applies this technique to wood pyrolysis oils and other biomass-based alternative liquid fuels.