A collaborative effort involving experiments, kinetic modeling, and computational fluid dynamics (CFD) was used to understand co-gasification of coal-biomass mixtures. The overall goal of the work was to determine the key reactive properties for coal-biomass mixed fuels. Sub-bituminous coal was mixed with biomass feedstocks to determine the fluidization and gasification characteristics of hybrid poplar wood, switchgrass and corn stover. It was found that corn stover and poplar wood were the best feedstocks to use with coal. The novel approach of this project was the use of a red mud catalyst to improve gasification and lower gasification temperatures. An important results was the reduction of agglomeration of the biomass using the catalyst. An outcome of this work was the characterization of the chemical kinetics and reaction mechanisms of the co-gasification fuels, and the development of a set of models that can be integrated into other modeling environments. The multiphase flow code, MFIX, was used to simulate and predict the hydrodynamics and co-gasification, and results were validated with the experiments. The reaction kinetics modeling was used to develop a smaller set of reactions for tractable CFD calculations that represented the experiments. Finally, an efficient tool was developed, MCHARS, and coupled with MFIX to efficiently simulate the complex reaction kinetics.

The book deals with development of comprehensive computational models for simulating underground coal gasification (UCG). It starts with an introduction to the UCG process and process modelling inputs in the form of reaction kinetics, flow patterns, spalling rate, and transport coefficient that are elaborated with methods to generate the same are described with illustrations. All the known process models are reviewed, and relative merits and limitations of the modeling approaches are highlighted and compared. The book describes all the necessary steps required to determine the techno-economic feasibility of UCG process for a given coal reserve, through modeling and simulation.

This book addresses the science and technology of the gasification process and the production of electricity, synthetic fuels and other useful chemicals. Pursuing a holistic approach, it covers the fundamentals of gasification and its various applications. In addition to discussing recent advances and outlining future directions, it covers advanced topics such as underground coal gasification and chemical looping combustion, and describes the state-of-the-art experimental techniques, modeling and numerical simulations, environmentally friendly approaches, and technological challenges involved. Written in an easy-to-understand format with a comprehensive glossary and bibliography, the book offers an ideal reference guide to coal and biomass gasification for beginners, engineers and researchers involved in designing or operating gasification plants.

With the development of societies fossil energy is no longer the only energy resource, and increasing attention had been paid to alternative energy. Biomass is considered to be one of the alternatives due to efficiency and low cost. This book presents biomass pyrolysis behavior for three main components: Cellulose, Hemicellulose and Lignin, and discusses the influence of mineral salts , zeolite catalysts and metal oxide on their pyrolysis.

Recent national and international emissions legislation, in particular sulphur-dioxide, and the rapid depletion of fossil fuels are forcing power producing industries to look at various alternatives, such as biomass and co-firing techniques. Biomass may be transported to the burners of a pulverised fuel (PF) boiler either mixed with the primary fuel, in general coal, or used in dedicated pipelines. In both cases, the transportation of biomass is different due to its composition, size and shape to the transportation of coal. This thesis investigates the computational modelling techniques for a biomass and biomass blend particle transportation (arboreal and flour) in a pipeline with a transverse elbow, the three-phase flow of a coal and biomass co-fire blend in the primary air annulus of a swirl burner and the combustion of a coal and pelletised straw mixture in a full scale furnace using dedicated burners for the biomass injection. The comparison of spherical and non-spherical drag models, under gravity, as well as Saffman lift, inter-particle collision and randomised impulsive wall collision models has been investigated. Good agreement was observed between the computational fluid dynamics (CFD) simulations and the experimental data, using a non-spherical drag model. In both cases, due to the dilute volume fraction and secondary air flow, inter-particle collisions and lift were insignificant. In the annulus, lateral regions of high particle concentration were predicted, which are not observed physically. Numerical simulations of a 300MWe tangentially fired furnace, co-firing bituminous coal and pelletised straw, have been performed and compared to experimental data. Bituminous coal was co-fired with pelletised straw. Good agreement was obtained between the CFD predictions and the experimental data so that the trends of furnace temperature, NOx emissions and carbon burnout reduction, as biomass load is increased, were observed. Quantitative prediction of unburnt carbon (UBC) and NOx require a more detailed picture of the processes within the furnace at higher temperatures than that currently provided by experimental data.