Shubhlabh Unicom Private Limited

Ichalkaranji, Kolhapur, Maharashtra

ADB

Air-Dried Basis. In coal sample analysis, ADB neglects the presence of moistures other than inherent moisture while DB (dry-basis) leaves out all moistures, including surface moisture, inherent moisture, and other moistures.

ARB

As-Received Basis. In coal sample analysis, ARB puts all variables into consideration and uses the total weight as the basis of measurement. ARB is the most widely used basis in industrial applications.

Ash content

Ash content is the non-combustible residue that remains after coal is burnt. Ash reduces handling and burning capacity, affects combustion efficiency and boiler efficiency and therefore increases handling costs.

ASTM

American Society for Testing and Materials

GAR

Gross As Received. Thermal coal is quoted on a GAR basis, except for Europe/ARA, Richards Bay 6, 000 kcal/kg, and Japan and Korea West CIF, which are quoted on a NAR (Net As Received) basis.

Fixed carbon

Fixed carbon is the solid combustible residue that remains in the furnace after volatile matter is distilled off, comprised mostly of carbon but also containing some hydrogen, oxygen, sulphur and nitrogen not driven off with the gases. It provides a rough estimate of the heating value of coal.

HGI

The relative ease with which coal can be pulverised depends on the strength of the coal and is measured by the Hardgrove Grindability Index (HGI). This empirical test indicates how difficult it would be to grind a specific coal to the particle size necessary for effective combustion in a pulverized coal fired boiler

Inherent moisture

Inherent moisture (or bed moisture) means moisture that exists as an integral part of the coal seam in its natural state, including water in pores, but excluding that present in macroscopically visible fractures.

Sulphur

Sulphur content in coal presents problems with utilization and resultant pollution, as it causes corrosion and fouling of boiler tubes, and atmospheric pollution when released in flue gases.

Total moisture

Total moisture in coal is represented by measuring weight loss from aggressive drying in an air atmosphere under rigidly controlled conditions of temperature, time and air flow. The presence of moisture is an important factor in both the storage and the utilization of coal, as it adds unnecessary weight during transportation, reduces the calorific value, and poses some handling problems.

Volatile Matter

Volatile matter is the material that is driven off when coal is heated to 950 °C in the absence of air under specified conditions. It consists of a mixture of gases, low-boiling-point organic compounds that condense into oils upon cooling, and tars. In general, coals with high volatile-matter content ignite easily and are highly reactive in combustion applications.

Indonesia is one of the world's largest producers and exporters of coal. Since 2005, when it overtook Australia, the country is the leading exporter in terms of thermal coal. A significant portion of its exported thermal coal consists of the medium-quality type (between 5100 and 6100 cal/gram) and the low-quality type (below 5100 cal/gram) for which large demand originates from China and India. According to information presented by Indonesia's Ministry of Energy and Mineral Resources, Indonesian coal reserves are estimated to last around 83 years if the current rate of production is to be continued.

Regarding global coal reserves, Indonesia currently ranks 9th, containing roughly 2.2 percent of total proven global coal reserves according to the most recent BP Statistical Review of World Energy. Around 60 percent of Indonesia's total coal reserves consists of the cheaper lower quality (sub-bituminous) coal that contains less than 6100 cal/gram.