Underground Coal Gasification and Combustion


Book Description

Underground Coal Gasification (UCG) is carried out in unmined coal seams, using wells drilled from the surface and converting coal into synthesis gas. The gas can be used for power generation and synthesis of automotive fuels, fertilizers and other products. UCG offers financial, social, and environmental benefits over conventional coal extraction and utilization methods and may play a critical role in ensuring energy security in the future. Underground Coal Gasification and Combustion provides an overview of underground coal gasification technology, its current status and future directions. Comprehensive in approach, the book covers history, science, technology, hydrogeology, rock mechanics, environmental performance, economics, regulatory and commercial aspects of UCG projects. The first book on the subject in forty years, it is unique in analysing more than a century of global UCG developments by experts from Australia, Canada, Poland, Russia, Ukraine, United Kingdom, the USA and Uzbekistan. Provides researchers, engineers, industry, educators and regulators with an authoritative overview of science and practical applications of underground coal gasification technologies Offers insight into efficiency, environmental performance, costs, permitting issues and commercial aspects of UCG projects Written by scientists and practitioners of UCG technology sharing hands-on experience of step-by-step UCG implementation




Coal Gasification and Its Applications


Book Description

Skyrocketing energy costs have spurred renewed interest in coal gasification. Currently available information on this subject needs to be updated, however, and focused on specific coals and end products. For example, carbon capture and sequestration, previously given little attention, now has a prominent role in coal conversion processes.This book approaches coal gasification and related technologies from a process engineering point of view, with topics chosen to aid the process engineer who is interested in a complete, coal-to-products system. It provides a perspective for engineers and scientists who analyze and improve components of coal conversion processes.The first topic describes the nature and availability of coal. Next, the fundamentals of gasification are described, followed by a description of gasification technologies and gas cleaning processes. The conversion of syngas to electricity, fuels and chemicals is then discussed. Finally, process economics are covered. Emphasis is given to the selection of gasification technology based on the type of coal fed to the gasifier and desired end product: E.g., lower temperature gasifiers produce substantial quantities of methane, which is undesirable in an ammonia synthesis feed. This book also reviews gasification kinetics which is informed by recent papers and process design studies by the US Department of Energy and other groups, and also largely ignored by other gasification books.• Approaches coal gasification and related technologies from a process engineering point of view, providing a perspective for engineers and scientists who analyze and improve components of coal conversion processes • Describes the fundamentals of gasification, gasification technologies, and gas cleaning processes • Emphasizes the importance of the coal types fed to the gasifier and desired end products • Covers gasification kinetics, which was largely ignored by other gasification books - Provides a perspective for engineers and scientists who analyze and improve components of the coal conversion processes - Describes the fundamentals of gasification, gasification technologies, and gas cleaning processes - Covers gasification kinetics, which was largely ignored by other gasification books




Coal and Biomass Gasification


Book Description

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.




Computational Modeling of Underground Coal Gasification


Book Description

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.




Underground Coal Gasification


Book Description













Gasification Technologies


Book Description

In contrast to traditional combustion, gasification technologies offer the potential for converting coal and low or negative-value feedstocks, such as petroleum coke and various waste materials into usable energy sources or chemicals. With a growing number of companies operating and marketing systems based on gasification concepts worldwide, this b




Combustion Front Propagation in Underground Coal Gasification


Book Description

Reverse Combustion (RC) enhances coal seam permeability prior to Underground Coal Gasification. Understanding RC is necessary to improve its reliability and economics. A curved RC front propagation model is developed, then solved by high activation energy asymptotics. It explicitly incorporates extinction (stoichiometric and thermal) and tangential heat transport (THT) (convection and conduction). THT arises from variation in combustion front temperature caused by tangential variation in the oxidant gas flux to the channel surface. Front temperature depends only weakly on THT; front velocity is strongly affected, with heat loss slowing propagation. The front propagation speed displays a maximum with respect to gas flux. Combustion promoters speed front propagation; inhibitors slow front propagation. The propagation model is incorporated into 2-D simulations of RC channel evolution utilizing the boundary element method with cubic hermetian elements to solve the flow from gas injection wells through the coal to the convoluted, temporally evolving, channel surface, and through the channel to a gas production well. RC channel propagation is studied using 17 cm diameter subbituminous horizontally drilled coal cores. Sixteen experiments at pressures between 2000 and 3600 kPa, injected gas oxygen contents between 21% and 75%, and flows between 1 and 4 standard liters per minute are described. Similarity analysis led to scaling-down of large RC (≈1 m) to laboratory scale (≈5 cm). Propagation velocity shows a strong synergistic increase at high levels of oxygen, pressure, and gas flow. Char combustion is observed, leaving ash-filled, irregularly shaped channels. Cracks are observed to penetrate the char zone surrounding the channel cores. 69 refs., 54 figs., 4 tabs.