What does pyrolysis mean?
Pyrolysis is the process of breaking down a material by applying heat, especially when oxygen is excluded. Instead of causing a substance to burn, it decomposes it into smaller chemical compounds, which may include gases, oils, char, and other products. The process is important in laboratories and industries because its products can be analyzed or used as fuels and chemical feedstocks. It is also associated with converting waste materials, including biomass and plastics, into energy or useful substances. In modern figurative use, the word can suggest the gradual breakdown of a social, political, or technological system, though this is less common than the scientific meaning. Understanding pyrolysis helps distinguish controlled thermal decomposition from combustion, in which a material reacts with oxygen and burns.
nounThe thermal decomposition of a material, especially an organic substance, by heating, typically in the absence of oxygen. The process breaks the material into simpler chemical compounds and is used in chemistry, petroleum processing, waste treatment, and materials production.
- The process of decomposing a material by heating, especially an organic material, usually in the absence of oxygen.
"The pyrolysis of organic waste can produce fuels and other useful chemical products."
"Researchers studied the pyrolysis of agricultural waste to produce bio-oil."
"The sample underwent pyrolysis at a high temperature in an inert atmosphere."
The plural is uncommon; the process is normally discussed in the singular or as an uncountable noun.
"The researchers compared the pyrolyses of several different waste materials."
The word pyrolysis literally means “fire-loosening”: heat is used to split a substance into simpler components rather than burn it.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does pyrolysis come from?
The word combines Greek pyr, meaning “fire,” with lysis, meaning “a loosening” or “splitting,” from the Greek verb luein, “to loosen or release.” These elements were combined in the sense “splitting by heat,” reflecting the process in which heat separates a substance into simpler compounds. The form belongs to the same Greek-derived family as terms such as pyrotechnic and pyrogenic.
Related word forms
How pyrolysis is actually used
The term is primarily technical and is common in chemistry, energy research, and environmental science. It is also used figuratively in some modern writing to describe the breaking down of systems, organizations, or ideas, although the literal scientific sense is dominant.
Easily confused with pyrolysis
Combustion generally involves burning in oxygen, whereas pyrolysis is the breakdown of a material by heat, typically without oxygen.