000			02719nab a2200193 4500
005			20260520000816.0
008			260224s2009 xxu
245	0	0	_aMercury emissions control in coal combustion systems using potassium iodide _bBench-scale and pilot-scale studies
260			_a _b _cene. 2009
270			_a15/04/2009 ; 15/04/2009
300			_a7 p. ; 236-243
520			_aTranscripción del resúmen publicado por el autor: Addition of halogens or halides has been reported to promote mercury removal in coal-fired power plants. In this study, bench- and pilot-scale experiments were conducted using potassium iodide (KI) for capture and removal of Hg in air and coal combustion exhaust. Two bench-scale reactor systems were used: (1) a packed-bed reactor (PBR) packed with granular or powder KI and (2) an aerosol flow reactor (AFR) with injection of KI particles. It was found that a higher temperature, a higher concentration of KI, and a longer gas residence time resulted in a higher Hg removal efficiency. A 100% Hg removal was achieved in the PBR above 300 °C using 0.5 g of powder KI and in the AFR above 500 °C with a KI/Hg molar ratio of 600 at a 5.8 s residence time. The low KI injection ratio relative to Hg indicated that KI is highly effective for Hg removal in air. Formation of I2 vapor by the oxidation of KI by O2 at high temperatures, which then reacts with Hg to produce HgI2, was identified as the pathway for removal. The pilot-scale experiments were conducted in a 160 kW pulverized coal combustor. KI was introduced in two ways: as a powder mixed with coal and by spraying KI solution droplets into the flue gas. In both cases the Hg removal efficiency increased with an increase in the feed rate of KI. Mixing KI powder with coal was found to be more effective than spraying KI into the flue gas, very likely due to the higher temperature, longer residence time of KI, and the formation of a secondary reactive sorbent. The Hg removal by KI was less efficient in the pilot-scale tests than in the bench-scale tests probably due to certain flue gas components reacting with KI or I2. Hg speciation measurements in both bench- and pilot-scale experiments indicated no oxidized mercury in the gas phase upon introduction of KI, indicating that the oxidation product HgI2 was captured in the particulate phase. This is very beneficial in coal-fired power plants equipped with electrostatic precipitators where particulate-bound Hg can be efficiently removed.
773	0		_tEnergy & fuels _g23
942			_cARTICULO
100	1		_aLing, Ying _940883
100	1		_aDaukoru, Michael _940884
100	1		_aSuriyawong, Achariya _940885
999			_c169562 _d169562