Cement, Energy and Environment

first part of this two-part article, the authors offer a critical view of the need for washing coal and the various options that are availabl e in India. Coal continu es to be the mains tay of the development of Indian economy, contributing to two-third of the country's d emand for conunercial energy. The total consumption of coal during 1996-97 was 297.6MT. of whi ch power and cap tive utilities con sumed about 214.5 MT. Coal consumption for power only during 1997-98 was more tha t 250 MTwhich as the trend shows, is expected to go up to about 450 MT by 2006-07. Multiplicity of supply sources have furthe r aggravated the si tuati on. There are very few power plants (except some pit head plants) that are receiving coa l from a s ingle dedicated source. Most are supplied E and F grade coal (ie, 85-90 per cent) while a few D grade (ie, 10- 15 per cent). Th e thermal power sta tions (TPS) therefore receive coals of h eterogeneous nature, both in quality and size, creating innumerable problems for the power plants. In order to dea l with these prob lems, the Ministry of Env ironment and Forests (MoEF) released a notification on September 19, 1997, directing the following two ca tegories of power plants to use beneficia ted coal beginning June 1, 2001: cost of cleaning is included in the coal price, whichvary from case to case, as does the impact on coal quality. The following methods for coal washing are considered economical: + Gravity based: Jigs, dense-medium sepa r a tors, fl owi ng fi lm and concentra tion table + Surface property based: Froth floatation + Dry methods: Cleaning coa rse coal with a fluidised air dense-medium or by rotary breakers An integra ted coa l preparation system developed by CFRI and fund ed by the government of India will produce four washed products suitable for different consumers. In order to establish the techno-economic viabili ty of the process, a demonstration plant of 1MTY input capaci ty has been proposed at the Patherdih washery premises. The likely output of the plants will be: + 24-27 per cent clean coal with 17.5+ I- 0.5 per cent ash for steel plants + 20-22 per cent cleans with 28 +I- 2 per cent ash for foundry use + 20-22 percentmidd1ingswi th34+l -2per cent ash as power house fuels • Any TPS located more than 1,000 km from + 25-30 per cent rejects with 60 +I- 2 per cent ash as fuel for fludised bed boiler houses the pit head + Any TPS located in urban areas, sensitive areas or criti ca ll y polluted areas, irrespective of their distance from the pit head Coal beneficia tion or washing is a process by which the qua lity of raw coa l is improved by either reducing extran eous matter that ge t extracted along w ith the mined coa l or the associated ash, or both. Coal clean ing plants are commonly located close to the mine and the Now tha t the government has decided to open up the coal sector for private proprietors, coa l washing shou ld be promoted as a viable private investmen t. The cost of set ting up of coal washeries may be trea ted as a component of the cap ital cost of power projects . Another benefit is that the cost of washing might come down, owing to the professionalism in p ri va te en terprise.