Boreskov Institute of Catalysis of the Siberian Branch of Russian ...

PP-IV-13CATALYTIC FLUE GAS CONDITIONING IN ELECTROSTATICPRECIPITATORS OF COAL-FIRED POWERPLANTSA.N. Zagoruiko, B.S. Balzhinimaev, E.A. Paukshtis, L.G. Simonova, S.V. Vanag,A.M. Zykov*, S.N. Anichkov*, N.D. Hutson**Boreskov Institute of Catalysis, pr. Akad. Lavrentieva, 5, Novosibirsk, 630090, Russia;fax: 7-383-3307678; e-mail: zagor@catalysis.ru*All-Russia Thermal Engineering Institute, Avtozavodskaya 14/23, Moscow, 115280, Russia;fax: 7-495-675-3725; e-mail: zykov-naot@yandex.ru**U.S. Environmental Protection Agency, Ariel Rios Building, 1200 Pennsylvania Avenue,Washington DC, 20460, USA; fax: 1-919-541-0554, e-mail: hutson.nick@epamail.epa.govCoal-fired power generation capacity in the Russian Federation is approximately29 GWe, accounting for about 19% of the total electricity generation in the area. Thoughsome decrease of coal consumption in Russia was observed in the 1990's, it is projected thatcoal's share of fuel usage in the country will be increased due to the fast rise of natural gasprices. Still, with a large amount of the coal used in Russian power plants having an ashcontent that exceeds 40 wt%, particulate matter (PM) retention in the flue gas is still a ratherurgent problem. Almost a half of such power plants are equipped with electrostaticprecipitators (ESPs) for control of PM emissions from. The collection efficiency of the ESPpartially depends on the electrical resistivity of the fly ash. Ash that is too resistive is difficultto charge and collect, and once collected, is difficult to remove from the ESP collectionelectrodes. High resistivity ash can also cause «back corona», in which corona is generated onthe collection electrodes, further degrading precipitator performance. Estimates indicate thatat typical flue gas temperatures of 140-150 °C, the combustion products of about 40% of thecoals fired in Russian and ex-USSR power plants possess unfavorable electrophysicalproperties.Therefore, there is great value in increasing the efficiency of ESPs by lowering theresistivity of fly ash. This may be accomplished via an ESP upgrade technique known as fluegas conditioning. Injecting small concentrations (2-10 ppm) of SO 3 is a proven way tocondition the flue gas for improved ESP performance. The surface absorbed SO 3 (or H 2 SO 4 )is very electrically conductive and effectively lowers the resistivity of the bulk fly ash.Controlled catalytic oxidation of SO 2 may be a cost-effective upgrade to condition the fluegas for improved ESP performance.418