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Aspects of the efficiency of calcium salts for the retention of sulphur in coal ash during combustion at 1200 k
Author(s) -
Brady Mark E.,
Burnett Michael G.,
Galwey Andrew K.
Publication year - 1993
Publication title -
journal of chemical technology and biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.64
H-Index - 117
eISSN - 1097-4660
pISSN - 0268-2575
DOI - 10.1002/jctb.280570404
Subject(s) - combustion , sulfur , coal , coal combustion products , microprobe , chemistry , aluminium , electron microprobe , silicon , calcium , mineralogy , fly ash , inorganic chemistry , environmental chemistry , metallurgy , materials science , organic chemistry
Electron microprobe analyses were made of the residual ash particles remaining after combustion in air at 1200 K of samples of representative coals used in thermal power plants and of samples of Northern Ireland lignite. Local associations of sulphur and calcium in the small areas analysed ( c. 10 μm) were ascribed to the formation of the relatively stable CaSO 4 . This correlation was not linear and it was concluded that locally CaO reacted preferentially with the acidic oxides of silicon and aluminium to form calcium alumino‐silicates. We recommend, therefore, that in assessing the amount of CaCO 3 or Ca(OH) 2 that must be added to a given fuel to achieve effective desulphurisation, due account must be taken of the ability of the constituent oxides in that coal to react with the additive.