How do Pyrolysis and Gasification Differ?

What is the difference between Pyrolysis/Gasification and Incineration?

Both gasification is the overall outcome term for processes which involve pyrolysis to turn wastes into energy rich fuels by heating the waste under controlled conditions.

Whereas incineration fully converts the input waste into energy and ash, these processes deliberately limit the conversion so that combustion does not take place directly.

Instead, they convert the waste into valuable intermediate materials that can be further processed for the prupose of materials recycling and/or energy recovery:

PYROLYSIS
Thermal degradation of waste in the absence of air to produce char, pyrolysis oil and syngas, eg the Conversion of wood to charcoal

GASIFICATION
Breakdown of hydrocarbons into a syngas by carefully controlling the amount of oxygen present, eg the conversion of coal into town gas.

Explanation of Terms

Char is created when an organic material—usually wood—is burned in a smothered environment. Char is the most common freshwater fish in Iceland. Char may also have the potential to sequester large amounts of carbon in the soil.

Charcoal is made by burning wood in the absence of oxygen, and lump charcoal is the product of that. One of the most important applications of wood charcoal is as a component of gunpowder .

Charcoal is a black substance that resembles coal and is used as a source of fuel. It is generally made from wood that has been burnt, or charred, while being deprived of oxygen so that what's left is an impure carbon residue.

There is a diagram which was published by Bridgwater which shows the nature of the difference between incineration and gasification and pyrolysis very clearly, and we have reporduced it below to show the differences, not only between gasification and incineration but with other combustion type processes.

If you need a larger version of this visit our Gasification Downloads page.

by Steve Evans with assistance from the Juniper Gasification and Pyrolysis Fact Sheet. -

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