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CALCINATION AND SINTERING OF SORBENTS DURING BOILER INJECTION FOR DRY SULFUR DIOXIDE CONTROL
Citation:
Kirchgessner, D. AND W. Jozewicz. CALCINATION AND SINTERING OF SORBENTS DURING BOILER INJECTION FOR DRY SULFUR DIOXIDE CONTROL. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/D-90/218.
Description:
The paper discusses the calcination and sintering of sorbents during boiler injection for dry sulfur dioxide (S02) control, with emphasis on calcium hydroxide--Ca(OH)2--because of its superior reactivity with S02 and its wide commercial availability. Calcination and sintering are of particular interest because they produce the surface area, pore volume, and pore size distribution which are responsible for reactivity of the sorbent with S02. Particle size is also a significant factor. Considerable EPA work has been directed toward increasing the calcium utilization of Ca(OH)2 during furnace injection. ydroxides have been produced using a variety of surfactants in the water of hydration in an attempt to reduce particle size by preventing agglomeration. Calcium lignosulfonate was shown to be the most cost effective material for reducing particle size in laboratory-scale hydrations. The modified Ca(OH)2 is 20 relative percent more reactive with S02 than unmodified Ca(OH)2 in laboratory scale reactivity testing. In addition to particle size reduction, retardation of sintering in the modified Ca(OH)2 has been shown to be responsible for the reactivity increase. Studies show that a small amount of S02 (<300 ppm) will produce calcium oxide (CaO) with enhanced resistance to sintering.