Gasification of carbonaceous materials has been reliably used for decades as an alternative to combustion of solid or liquid fuels on a commercial scale to produce heat, industrial chemicals, fertilizers, in the refining industry, and in the electric power industry. Furthermore, it is easier to clean gaseous mixtures than it is to clean solid fuels or high-viscosity liquid fuels. Clean gas can be used in internal combustion-based power plant that would suffer from severe fouling or corrosion if solid or low quality liquid fuels were burned instead.

Gasification is a time-tested, reliable, and flexible technology that converts carbon-containing materials, including waste and biomass, into electricity and other valuable products, such as chemicals, fuels, substitute natural gas, and fertilizers. Gasification does not involve combustion (burning), but instead uses little or no oxygen or air in a closed reactor to convert carbon-based materials directly into a synthetic gas, or syngas. It is this intermediate product, synthesis gas (syngas), that makes gasification so unique and different from combustion. The gasification process breaks these materials down to the molecular level, so impurities like nitrogen, sulfur, and mercury can be easily removed and sold as valuable industrial commodities. Gasification can also recover the energy locked in biomass and municipal solid waste, converting those materials into valuable products and eliminating the need for incineration or landfilling. Biomass can also be blended with coal as a feedstock for electricity generation to lower its carbon footprint.

The chemistry of the gasification process is based on the thermal decomposition of the feedstock and the reaction of the feedstock carbon and other pyrolysis products with oxygen, water, and fuel gases such as methane and is represented by a sequence of simple chemical reactions. However, the gasification process is often considered to involve two distinct chemical stages: (i) devolatilization of the feedstock to produce volatile matter and char, (ii) followed by char gasification, which is complex and specific to the conditions of the reaction – both processes contribute to the complex kinetics of the gasification process.

The book also presents the elements of the Fischer-Tropsch process, which is a catalytic chemical reaction in which carbon monoxide (CO) and hydrogen (H₂) in the synthesis are converted into hydrocarbon derivatives of various molecular weights. The process is a tried-and-true process that has been commercially demonstrated internationally The process for more than 75 years using synthesis gas. As an abundant resource in many non-oil producing countries, coal has long been exploited as a solid fossil fuel. As oil and natural gas supplanted coal throughout the last two centuries, technologies developed to convert coal into other fuels. Proponents of expanding the use of the Fischer-Tropsch process argue that the United States and many other countries could alleviate its dependence on imported petroleum and strained refinery capacity by converting non-petroleum feedstocks to transportation fuels.

This book deals with (i) gasification chemistry, thermodynamics, (ii) gasification feedstocks – such as coal, petroleum resids, biomass, waste, and other feedstocks, (iii) gasification processes and the suitability of different feedstocks, (iv) underground coal gasification, (v) gas cleaning, (vi) synthesis gas and hydrogen production, (vii) the Fischer-Tropsch process leading to the production of fuels and chemicals, and (viii) the potential for gasification in the future.

Furthermore, it is the purpose of this book to promote a better understanding of the role that gasification can play in providing the power, chemical and refining industries with economically competitive and environmentally conscious technology options to produce electricity, fuels, and chemicals while adhering to environmental regulations.