Which of the following statement(s) is / are correct for pyrolysis?

Explanation:

Pyrolysis:

•  It is the process in which most of the organic matter upon heating in an oxygen-free atmosphere splits through a combination of thermal cracking and condensation reactions into gaseous, liquid, and solid fractions.
• The process typically occurs at temperatures above 430 °C (800 °F) and under pressure.
•  It simultaneously involves the change of physical phase and chemical composition and is an irreversible process. So it is an endothermic process.
• This method is suitable for the disposal of solid waste which poses high calorific value but is comparatively costlier than other methods of disposal.

 Important Points

Some other processes used for waste disposal
Incineration:

• It involves of two stages involved such as drying and combustion. Drying and combustion may be accomplished either in separate units or successively in the same units depending upon the temperature constraints or control parameter. It is an exothermic process.

Landfilling-

• In this method refuse is dumped into low lying areas in layers of approximate depth of 1.5m. Each layer of refuse is termed as a cell. Each layer is compacted properly and left for 7 days for its aerobic decomposition & it is covered with a layer of mud to carry out further decomposition.

Thermal Treatment-

• In thermal treatment the waste is being brought in contact with the steam or any other process which helps in combustion for sufficient duration in order to stabilize the waste.