A combustible black and/or brownish-black sedimentary rock occurring in rock strata in layer or veins is called Coal, or coal seam. It is a flammable black hard rock which is commonly used as a solid fossil fuel. It mainly consists of carbon about up to 65-90% with some percentage of hydrogen, oxygen, sulfur and nitrogen.
Metamorphic rocks are the hardest form of coal as they were changed in high temperature and pressure, for example Anthracite.
In power station, coal plays a major role for the production of electricity. Nowadays natural gas and hydroelectricity are preferred over coal as they are less expensive and less polluting technologies.
Coal when heated in to high temperature in absence of oxygen, it convert itself into coke which is better fuel than coal.
Why Coal testing is required?
Being highly heterogeneous in nature, to accurately predict its behavior during application several new analytical techniques are developed for its characterization. To avoid economic consequences, analysis need to be sufficiently accurate as its supply is in very large amount. Coal undergoes oxidation when exposed to the atmosphere and also has tendency to lose or gain moisture. As coal analysis method are empirical in nature and to obtain repeatable and reproducible results, it is necessary that all coal analysis should follow procedural guidelines.
There is a requirement of reliable standard test method for coal analysis which is acceptable by seller and buyer.
Due to above reasons coal analysis is important Sigma Test & Research Centre provide independent survey service to ensure the accurate “quality, survey and superintending services” of the coal. Sample can be sent or drawn, in accordance with international testing standard such as ASTM, ISO, BSI and JIS.
Coal Testing Facilities :-
1. Calorific Value: –The calorific value of a fuel is the quantity of heat produced by its combustion at constant pressure and under “normal” conditions (0˚ and 1 bar). In other words, calorific value or energy content is same as the heat of combustion. It values varies on the geographical age, formation, ranking and location of the coal mine. It also determined how much coal will be required to generate per unit of electricity.
2. Proximate analysis (Moisture, Volatile Matter, Ash and Fixed Carbon):- Weight of fixed carbon, moisture, ash and volatile is indicated by proximate analysis. Contribution to the heating value of coal is directly linked to the fixed amount of carbon and volatile combustible matter. During burning, fixed amount of carbon acts as a main heat generator. It can be determined by simple apparatus. Easy fuel ignition is indicated by high volatile matter.
3. Ultimate Analysis:- Coal component elements, solids or gaseous are determined by ultimate analysis. Air required for combustion and the volume and composition of the combustion gases is determined from “Ultimate Analysis”. To calculate flame temperature and flue duct design etc. information regarding ultimate analysis is important.
4. Ash Analysis:- When coal is thoroughly burnt some non-combustible residue are left over, that is called Ash content. It is expressed as percentage of original weight. During combustion when carbon, oxygen, sulfur and water driven off it represent bulk mineral matter.
5. Ash Fusion Temperature:- For Steam Power Generation, behavior of the coal’s ash residue at high temperature is very critical factor in coal selection. Clinker coal is the coal which has ash that fuse into a hard glassy slag which is usually unsatisfactory in furnaces as it require cleaning. These tests are part of development of automated techniques for performing measurement requiring no intervention by operator. Here, fusion temperatures are valuable guides to high-temperature behavior of fuel inorganic material.
Hence, the requirement of Coal Testing is clear, so if you need further information regarding this service then you can get the information at www.sigmatest.org