Abstract |
An experimental study was made of the injection of SO3 or H2SO4 gaseous conditioning agent to alleviate the problem of high electrical resistivity of fly ash. This problem interferes with the electrostatic precipitation of fly ash in power stations burning low-sulfur coals and thus providing very low concentrations of H2SO4 as a naturally occurring conditioning agent. Experimental measurements included in the study consisted of determinations of fly-ash resistivity in situ and analyses of coal, flue gases, and fly ash with injected SO3 and H2SO4 concentrations up to 50 ppm. For comparison with conditioning by injected SO3 and H2SO4, a parallel study was made of conditioning by H2SO4 as produced naturally during the burning of coal. To compare the economic aspects of different processes of SO3 and H2SO4 injection, an analysis was made of the various capital and operating costs in existing injection facilities. NH3 was studied as a means of coping with poor precipitator efficiency in a power station burning a high-sulfur coal and thus producing an undesirably high concentration of H2SO4. |