Definition - What does Volatile Matter mean?
Volatile matter is products (such as a gas or a vapor) given off by a material, and determined by definite prescribed methods. One of its main industrial uses is in determining the properties of coal.
In coal, volatile matter is those substances, other than moisture, that are given off as gas and vapor during combustion. This is usually a mixture of short- and long-chain hydrocarbons/aromatic hydrocarbons and some sulfur.
It is important for evaluating coal's combustion and coking characteristics. Standardized laboratory methods are used in analysis.
Corrosionpedia explains Volatile Matter
Volatile matter is a substance that vaporizes. A substance’s volatility is measured by its vapor pressure, the point at which a substance turns from a solid to a gas, or vice versa. For fats and oils, volatile compounds are released when fat or oil is heated.
A substance with a high vapor pressure vaporizes easily, while one with a low vapor pressure requires a lot more energy. When applied to a material, the vapor pressure determines its volatility. Since a volatile substance has a tendency to be more flammable than a non-volatile one, it is important to study the volatility in a fuel source to determine its overall usefulness.
The volatile matter of coal is determined by heating the coal to 1,740°F (950°C) under carefully controlled conditions and measuring the weight loss, excluding the weight of the moisture driven off at 220°F (105°C). This test is typically performed in a vacuum.
Analysis of these gasses is one of the major ways to determine the best uses for coal from different areas. Some types have higher concentrations of certain materials, and that allows that particular coal to perform better in certain functions. For instance, lignite has a very high volatile matter content, along with high moisture. The moisture and volatility analysis shows that it burns for a long time with a low heat and a lot of smoke.