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Gasification is a thermo-chemical process that uses heat to convert any carbon-containing fuel into a clean burning gas commonly referred to as “syngas”. Gasification differs from combustion because it uses just 20% to 30% of the air or oxygen needed for complete fuel combustion. During gasification, the amount of air supplied to the gasifier is carefully controlled so that only a small portion of the fuel burns completely. This “starved air” combustion process provides sufficient heat to pyrolyze and chemically break down the balance of the fuel into producer gas - commonly called “syngas”.
Syngas is composed primarily of carbon monoxide, hydrogen and methane, as well as vapourized pyrolysis liquids and hydrocarbons. Unlike energy derived from the direct incineration of many waste fuels, syngas is a clean burning fuel that can be used as a substitute for natural gas, fuel oil or propane to produce process heat, steam, hot water and/or electricity using conventional energy recovery equipment. Syngas can also be synthesized and used as a basic chemical building block for a large number of products in the petrochemical and refining industries.
The principles of gasification have been well understood for over 200 years. Coal gasification was widespread during the late 1800s, providing fuel for urban lighting and power generation. The abundance of inexpensive oil and gas resulted in a decline for gasification after World War II. In recent years, gasification has experienced a resurgence due to escalating fossil fuel and electricity costs. Today, gasification is recognized as one of the most versatile, efficient and cleanest ways to convert low cost solid fuels such as wood residue and coal into thermal energy or electricity.
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