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U.S. Department of Energy
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Fuel rich sulfur capture in a combustion environment

Conference ·
OSTI ID:5244044

A major concern associated with the combustion of coal for heat and electricity is the emission of acid rain precursors, NO/sub x/ and SO/sub 2/. Dry calcium based sorbent injection is a potential method for reducing SO/sub 2/ emissions from existing coal-fired boilers. A great deal of study has been devoted to the fuel lean SO/sub 2/ reaction: CaO + SO/sub 2/ + 12O/sub 2/ ..-->.. CaSO/sub 4/ The fuel rich analogies: CaO + H/sub 2/S ..-->.. CaS + H/sub 2/O, CaO + COS ..-->.. CaS + CO/sub 2/ are kinetically faster than the SO/sub 2/ reaction. The fuel rich reactions have not been extensively studied particularly under combustion conditions. In this study a refraction lined, down fired natural gas furnace was used to study fuel rich sulfur capture as a function of sulfur concentration (750-3000 ppm), molar ratio of calcium to sulfur (CaS = 1 to 4), residence time (0.30 to 0.65 sec), quench rate (450 to 900/sup 0/Fsec), stoichiometric ratio in the rich zone (SR = 0.65, 0.75), and sorbent type (Marblehead hydrate and Fredonia carbonate). The fuel rich sulfur species H/sub 2/S and COS were monitored in a near continuous fashion using a gas chromatograph equipped with a flame photometric detector (GC-FPD) and an automatic sampling system which sampled every 30 seconds. Below the fuel rich zone, 25% excess air was added and the ultimate fuel lean capture was measured using a continuous SO/sub 2/ monitor. Under fuel rich conditions calcium utilization increases with increasing sulfur concentration and decreasing CaS. The results on the lean side are very typical of lean capture data reported by others; i.e. the calcium utilization is weakly dependent on CaS and sulfur concentration.

OSTI ID:
5244044
Report Number(s):
CONF-870484-
Country of Publication:
United States
Language:
English