Low-graded coals to upgrade

Abstract

Coal can be defined as a chemically and physically heterogenous, “combustible”, sedimentary rock consisting of both organic and inorganic materials. Organically, coal consists primarily of carbon, hydrogen, and oxygen, with lesser amounts of sulphur and nitrogen. Inorganically, coal consists of a range of ash-forming compounds distributed throughout coal. Major types of analysis are proximate analysis, ultimate analysis and calorific value analysis. Heat value or calorific value determines energy content of a fuel. It is property of coal that depends on its chemical composition and moisture content. Important fuel property is its calorific or heat value Moisture content is a very important property which can greatly affect the burning characteristics of coal. Coal rank defines type of coal like lignite to sub bituminous and medium to high volatility. Low rank or low-grade coals are most abundant distribute around several regions. Contribution of low-rank coal is significant in energy sectors and chemical feedstock to industries. Hard coal reserves are gradually depleting, and mining operation at deeper coal seam with greater difficulties as well as cost of exploration is high. Therefore, low-grade coal can be used as alternative energy source to minimize these problems. Low-rank coals are generally related with high mineral matter and moisture content, which exerts substantial impacts on their consumption including pyrolysis, liquefaction, gasification and combustion process.

Keywords

Coal, dry beneficiation, electrostatic technique, rotary, triboelectrostatic separator, high-gradient magnetic separation, chemical beneficiation; physical beneficiation; ash.