NAGPUR, May 7: While a hue and cry is being raised over the pollution caused by the emissions of the Koradi Thermal Power Station (KTPS), no action has been taken for last five years on a project report proposing to reduce the impurity content in non-coking coal used by the KTPS.

The implementation of the report, submitted as a conclusion to studies and pilot plant scale experiments, by the local Coal Survey Laboratory of the Central Fuel Research Institute (CFRI) is in limbo with both the supplier of the coal, Western Coalfields Limited (WCL) and the utiliser, Maharashtra State Electricity Board (MSEB), which runs the KTPS, not paying attention to the issue.

The studies made by the laboratory, under a project sponsored by WCL has shown that beneficiation (washing) of the non-coking coal, utilised in the thermal power station, will reduce the ash and sulphur content in the coal, the main pollutants, to the tolerable 40 per cent and 0.5 per cent mark. The washing will also enhance the calorific value of the coal and thereby the load factor of the plant up to its intended 500 MW capacity, as the other impurities such as silica will also be removed in the process.

According to sources, the studies regarding beneficiation of the coal was submitted to the WCL in 1992, but there has been no implementation yet. It seems that both the parties are too busy in their mundane affairs such as maintaining production level and deadline and ensuring reserves to be utilised in future, to show interest in this aspect.

While the WCL deems its responsibility is only to supply coal on time, the MSEB is more concerned whether they have enough coal to run the plant for the next seven days. Although there are stringent stipulations regarding the impurity content for the coal to be utilised in the power plants, the coal from Wardha Valley Coalfield is regularly being used at the KTPS.

Dr B D Muzumdar, officer-in-charge of the Coal Survey Laboratory, told The Indian Express, that the KTPS uses the non-coking coal, mined from the Wardha Valley Coalfield by the WCL. This coal contains around 50-55 per cent ash and between 1.0 to 3.8 per cent sulphur, quite high than the tolerable limits.

To add to this, other impurities in the form of sandy shale and grey shale from the overburden and minefloor, rich in silica content, gets mixed with the coal during the mining process.

While the ash and the sulphur are the main pollutants, producing ash slurry containing toxic trace elements and the deadly sulphur dioxide gas respectively, the other impurities makes the coal rich in silica content, which in turn corrodes the machinery and thus reduces the plant life considerably. Due to the presence of these impurities the calorific value of the coal is also reduced, finally hitting the plant load factor, which has been reduced from 500 MW to 250-300 MW.

The beneficiation process will cost something like Rs 60-80 per tonne and 10-12 per cent of coal will be rejected during washing. However, the WCL is ready to provide this extra 10-12 per cent of coal to the MSEB, Muzumdar said.

He said during the process, pyritic sulphur will be recovered. This pyritic sulphur is amenable to washing and around 10-22 per cent of sulphur could be recovered from it, which has great commercial value, mainly due to its utilisation in manufacture of sulphuric acid. It is very important to wash the non-coking coal before use, as the impurities are not only harmful to the environment and human health, but also bad for the plant health and life. However, there are no washeries for the non-coking coal anywhere in India. The only washeries that exist, wash the coking coal, that are utilised in the metallurgical industry.

The laboratory recently also organised a seminar on quality coal, where this aspect was stressed, he said.

Copyright © 1997 Indian Express Newspapers (Bombay) Ltd.