Strategic Action Plan - International Environmental Technology Centre

Strategic Action Plan Report
Pyrolysis, often incorporating gasification, is a thermal process where organic materials in the waste are
broken down under pressure and in the absence of oxygen. The process works best when the input waste is
carbon-rich, preferably sorted or pre-sorted. Best results are obtained from single stream wastes such as
sewage sludge, plastics, wood, tyres, or agricultural wastes. Where MSW is to be used it should be pre-sorted
to remove the majority of the non-organics and processed to homogenise the feedstock. The Pyrolysis
process produces a liquid residue and gaseous output which may be combusted to generate electricity. A solid
slag is also produced which may require disposal or additional processing.
Figure 5.8: Schematic of inputs and outputs of a Typical Pyrolysis process
Gasification usually operates at a higher temperature range to pyrolysis, with the addition of an oxidant (either
air or oxygen) and the output from a pyrolysis plant may be fed into this process. Gasification of organic
derived wastes will produce a gas which can be combusted to generate electricity and a char which usually
requires disposal if no markets are available.
Figure 5.9: Schematic of Inputs and Outputs of a typical Gasification process
ISWM Plan for Pune 106