Thermal Process Technology

The incineration (combustion) process

The incineration (combustion) of carbon-based materials in an oxygen-rich environment (greater than stoichiometric), typically at temperatures higher than 850o, produces a waste gas composed primarily of carbon dioxide (CO2) and water (H2O). Other air emissions are nitrogen oxides, sulphur dioxide, etc. The inorganic content of the waste is converted to ash. This is the most common and well-proven thermal process using a wide variety of fuels.

Gasification is the thermal process that converts carbon-containing materials, such as coal, petcoke, biomass, sludge, domestic solid waste to syngas which can then be used to produce electric power, valuable products, such as chemicals, fertilizers, substitute natural gas, hydrogen, steam and transportation fuels.

Pyrolysis is the thermal degradation of carbon-based materials through the use of an indirect, external source of heat, typically at temperatures of 450 to 750°C, in the absence or almost complete absence of free oxygen. Pyrolysis technology provides a big opportunity for the conversion of municipal solid wastes,scrap tires, agricultural residues, non-recyclable plastics etc. into clean energy.

Plasma technology is showing promise for a variety of waste processing applications. The attractiveness of plasmas results from the capability to provide high temperatures, a high degree of controllability, and the use of electricity for heating rather than heat from combustion. Plasma refers to every gas of which at least a percentage of its atoms or molecules is partially or totally ionized. In a plasma state of matter, the free electrons occur at reasonably high concentrations and the charges of electrons are balanced by positive ions. As a result, plasma is quasi-neutral.