THE USE OF COAL WASHERY REJECTS.

By C.G. Mrig Managing Director Aryan Coal Benefications Pvt. Ltd.

1.1 In India, 65% of the energy requirement is met by coal and the situation is likely to continue for a long time in view of the high cost of the imported crude, depleting indigenous oil sources and likely stagnation in the capacity building of nuclear power stations.

1.2: Out of the total resources of coal, 85% are of non-coking variety and of inferior quality. The average ash as delivered to major customers like power houses is about 42%. Since 75% of the coal produced in the country is from open cast mines, there is further deterioration in quality.

1.3: During late '90s, Ministry of Environment & Forests, GoI stipulated that:

a) All power houses located more than 1000 Kms from the pit head should use a coal having =<34% ash coal. This is mandatory for those plants which is situated in sensitive areas irrespective of their distance from the pitheads.

b) For the existing power houses, they should achieve 100% fly ash Utilisation in 15 years.

c) For the new power houses the dead line is by 9-years after the MoEF's stipulation came into effect.

1.4: Since the availability of 34% ash coal is very limited and because of MoEF stipulation, there is a big opportunity for coal beneficiation.

2.0: Washing of Indian Coal:

Indian Coal is considered difficult to wash because of high near gravity material. This implies that when coal ash is reduced by beneficiation, the energy loss in the rejects increases.

To make coal washery a viable proposition, rejects are to be used in such a way that they generate economic revenue.

3.0: Requirement of Thermal Coal (Distance wise) (Million Tonnes/Annum)

4.0: CLEANER COAL TECHNOLOGY PROGRAMME

Programme Managed by Department of Trade & Industries Government of UK

Project Partners: - Dargo Associates, UK & - Aryan Coal Benefications (P) Ltd., India

Aryan was the Indian Partner for the study conducted by the Department of Trade & Industry, Government of UK to find out the feasibility of the washing of Indian Coal for Indian Power Generation Companies. M/s Dargo Associates, UK was our counterpart for this study.

Objective

The overall objective of the study is to demonstrate the technical and economic feasibility of producing low ash fuel for major power stations and recover heat lost in coal preparation plant waste by combustion in fluidised bed based power plant.

Evaluation of Financial Advantages

Evaluation of the financial advantages of the scheme began with the determination

of the washability of a typical power station coal. A sample of coal was taken at the

Dipka Coal Washery of Aryan Coal in Dist.: Korba, Chhattisgarh. After the laboratory determinations, a coal preparation plant simulation program (LIMN) was used to determine the optimum level of coal preparation balanced against the cost of the FBC power plant.

A simulated product sample was prepared based on the coal preparation studies. This was analysed for combustion characteristics. These parameters were

used to determine the change in performance and consequently the cost of generation at an existing power station. The Ropar Power Station of PSEB

provided detailed information about its boilers and auxiliary plant. Powergen Ltd. applied the plant data and coal analysis, to the VISTA computer simulation of coal fired boilers. The results of the simulation runs showed that the existing power plant could significantly improve its heat rate and lower its cost of generation.