•   Most of the Indian coals contain higher percentage of inorganic impurities compared to the coals of western world and Australia. The inorganic impurities present in Indian coals are intimately mixed with the coal matrix. As such, its removal is difficult.

•   Coal has been the main source of energy in India and through increased coal production, coal is still fulfilling the energy demands of the country. The quality of coal has always remained a matter of concern: high ash, poor wash ability, low calorific content etc.

Coal Quality:

•   Coal is categorised or graded based on type, ash content, moisture content, useful heat value (UHV) and gross calorific value (GCV).

•   Coking coal is graded on the basis of ash content, while semi-coking coal is graded based on ash and moisture content and non-coking coal is graded based on three parameters—UHV, ash and moisture content and GCV.

•   Indian coals by their very nature are high in ash content but low in sulphur content (which is a good thing). Indian coal is its high ash fusion temperature of about 1,500°C.

•   PAT (Perform, Achieve and Trade), a target setting methodology for power sector in India under the National Mission on Enhanced Energy Efficiency (NMEEE), 2008 is a major initiative taken by the Indian government that raised the demand for good quality coal. It is a regulatory mechanism that enforces energy intensive industries to reduce specific energy consumption. This is enabled through market-based mechanisms to enhance the cost effectiveness through certification of saving the excess energy that can be traded.

•   PAT Cycle-I (2012-13 to 2014-15) was introduced to reduce the energy consumption from eight energy intensive sectors—aluminium, cement, chlor-alkali, fertiliser, iron and steel, paper and pulp, thermal power plant and textile.

•   THE most significant characteristic of Indian coal is its high ash content, which varies from 35 to 45 per cent, compared with that of coal in other parts of the world, which is around 15 per cent.

•   With legislation requiring, since June 2001, thermal power plants to use coal with less than 35 per cent ash content, and with the quality of Indian coal deteriorating over the years, development of more efficient technologies that can handle high-ash Indian coal, such as Integrated Gasification Combined Cycle, becomes important.

•   Besides high ash content, another reason for entrained gasifiers (that operate at higher temperatures than fluidised bed gasifiers), commonly used in IGCC plants abroad, being not suitable for Indian coal is its high ash fusion temperature of about 1,500{+0}C.

•   The ash chemistry of Indian coal is such that it is high in silica and alumina.

•   The ash is also highly abrasive because of high quartz content, which can lead to erosion of the syngas cooling system when it gets fused.

•   But in a fluidised bed, since the operating temperature is much lower than the fusion temperature, this problem is not serious, according to BHEL.

•   However, Indian coals sulphur content is low, about 0.5 per cent. So, from a gas clean-up perspective, the flue gas desulphurisation (removal of SOx gases) and NOx removal system is not economically justifiable and, therefore, not important. Also, in the Indian context, this is unnecessary to meet emission norms.

Additional Information

Coal quantity:

•   India now ranks as the third largest coal producing country in the world after China and USA.

•   It has been estimated that the country has 301.56 billion tonnes of coal.

•   Currently India meets about 55 per cent of India’s primary commercial energy needs (Ministry of Coal, 2017). About 75 per cent of power generation is coal based in India.

•   Odisha leads in the production of coal, followed by Chhattisgarh, Jharkhand, Madhya Pradesh, Telangana, Maharashtra and West Bengal.

Consumption:

•   The largest consumers of coal in India are electricity generation (637.95 MT), the steel and washery industries (69.50 MT), the sponge iron industry (12.23 MT) and the cement industry.

Fact for prelims:

•   Uttam portal: Unlocking Transparency by Third Party Assessment of Mined Coal to ensure accountability, transparence, effectiveness and efficiency in coal ecosystem.