Coal is a combustible black or brownish-black sedimentary rock with a high amount of carbon and hydrocarbons. Coal is classified as a nonrenewable energy source because it takes millions of years to form.Coal contains the energy stored by plants that lived hundreds of millions of years ago in swampy forests.
Layers of dirt and rock covered the plants over millions of years. The resulting pressure and heat turned the plants into the substance, we call coal. We have very well experience about in coal testing. We have analysis of coal in all over India.
Types of coal
Coal is classified into four main types,or ranks: anthracite,bituminous,subbituminous, and lignite.The ranking depends on the types and amounts of carbon the coal contains and on the amount of heat energy the coal can produce.The rank of a coal deposit is determined by the amount of pressure and heat that acted on the plants over time.
Bituminous:- Coal contains 45%–86% carbon.
Anthracite: - Contains 86%–97% carbon & generally has the highest heating value of all ranks of coal.
Subbituminous:- Coal typically contains 35%–45% carbon, and it has a lower heating value than bituminous coal.
Lignite:- Contains 25%–35% carbon and has the lowest energy content of all coal ranks. Lignite coal deposits tend to be relatively young and were not subjected to extreme heat or pressure. Lignite is crumbly and has high moisture content,which contributes to its low heating value.
Some of the Common Tests conducted on Coal include
- Ash Analysis - Al2O3, SiO2, CaO, MgO,TiO2, Na2O, K2O, S etc.,
- Ash Fusion Temperature.
- Coke Reactivity.
- Calorific Value(Gross/net)
- Hard-grove Grindability Index.
- Proximate analysis- Moisture,Volatile matter,Ash and Fixed Carbon.
- Ultimate analysis - C,H,O,N S and Ash.