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Show (v) (vi) Under staged combustion, when the PAF is 0.95 or higher, bed temperature has a dramatic effect on sulphur retention . An increase of the temp from 830 C to 880 C reduces it to 9% . If the PAF is less than 0.95 then sulphur retention is always poor, between 10-15% and retention is relatively insensitive to bed temperature. (vii) In order to achieve high sulphur retention under staged condition then the PAF level should not fall below 0.95 and the bed temperature should be below 850 C. The optimum temperature for this level is 830 C. (viii) Over the fluidizing velocity range of 1-2 mis, at a PAF of 0.95 the best sulphur retention occurs at a velocity of 1.5 mise ACKNOWLEDGEMENT The authors wi shes to acknowl edge the fi nanc i a 1 support of Mi n i stry of Science & Technology, Government of Pakistan to undertake research at University of Leeds. 1. 2. 3. 4. 5. 6. 7. 8. REFERENCES Gibbs, B.M - The influence of Air Staging on the NO emissions from a fluidized bed coal combustor, 16th Symposium (lnt) on Combustion, U.S.A. 1976, 461-474. Gibbs, B.M and Salam, T.F - The reduction of NO emissions from a fluidized bed combustor by staged combustion combined with NH3 addition, 22nd Symposium (lnt) on Combustion, 1988. Nack, H et al - Proc., 6th Int. Conf. on Fluidized Bed Combustion, at Atlanta, USA, 1980, Vol III, PP 979. Tatabayashi, J, et al-Proc., 6th Int. Conf. on Fluidized Bed Combustion, at Atlanta, USA, 1980, Vol III. . Valk M et al - Proc., 9th Int. Conf on Fluidized Bed Combustion at Boston, USA, 1987, Vol. II, PP 784. Salam T F et al, Characterizing corrosion potential in fluidized bed combustors. lOth International conference on fluidized bed combustion USA, 1989, pp 575-581. Bramer E A et al, Sulphur capture under reducing conditions at AFB combustion, 4th International fluidized combustion conference, London, U.K, 1988, Vol I, pp 1/11/1-1/11/11. Spitsbergen U et al, Desulphurization qual ity of 1 imestone based sorbents tested under multistage fluidized bed combustion conditions, proceed i ngs of 5th Annual Internat i ona 1 Pi ttsburgh coal conference, Sept 1988. (17) |
