Comparison on preparation of ultra-clean coals with three deashing methods
- Research Center of Coal Slurry Technology (China). World Lab.
- China Univ. of Mining and Technology, Beijing (China). Beijing Graduate School
This paper gives a comparison on the advantages and disadvantages of three deashing methods, which include chemical processing, oil agglomeration and selective flocculation. Seventeen coals from eight provinces in China were tested by the three deashing methods. It was found that two keys of deashing methods are the mode of grinding and oil consumption. Low oil consumption can reduce production cost, and highly effective grinding can reduce energy consumption. Conventional wet grinding with a ceramic ball is a technically feasible process for reducing average particle size below 10 microns. The oxygen content in coals is a very important factor that affects oil agglomeration and selective flocculation. If the oxygen content in coals is high, the ash contents of the coals are not easily reduced below 1%. Some additives should be added in the coal pulp to improve the surface nature of coals. By the chemical processing method, ultra-clean coal with ash content about 0.2 % can be attained from No.2 coal, and with ash content about 0.6 % from No.1. The ash contents of No.9 and No.10 coals can be reduced lower than 1% by oil agglomeration. For coals No.10 and No.12, being typical in China, the ash contents were respectively reduced to 0.83% and 0.86% by selective flocculation. The production cost of the chemical processing method is high and the environmental contamination is serious. However oil agglomeration has a high recovery and high deashing rate, but a large amount of oil is used. Comparison shows that the selective flocculation method is a low cost method and can be widely applied in the future.
- OSTI ID:
- 324839
- Report Number(s):
- CONF-970931--
- Country of Publication:
- United States
- Language:
- English
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