5. Gasification

5.1 Thermal process

Gasification is a process for the total conversion of organic matter into gas by partial combustion (figure 10 ). Oxidation takes place at medium to high temperature (850 to 1,400°C) with a limited amount of oxidizing agent (air, steam or pure oxygen). The result is the formation of combustible heterogeneous gases and ash. These gases are composed of carbon dioxide, methane, carbon monoxide, hydrogen and possibly nitrogen (from the combustion air). Gasification is only possible with sludge dried to at least 70% dryness [3] .

There are a number of different gasification...