Retrofit of waste-to-energy facilities equipped with electrostatic precipitators. Volume I: Report

摘要

To help lower the cost of compliance for waste-to-energy facilities, a retrofit technology using water spray temperature reduction combined with dry acid gas control reagent and powdered activated carbon (PAC) injection was tested in November, 1995 as part of an American Society of Mechanical Engineers' (ASME) Center for Research and Technology Development (CRTD) effort supported in part by the Department of Energy's National Renewable Energy Laboratory (NREL) and directed by the ASME Research Committee on Industrial and Municipal Waste. 2,000 mg/dsm(sup 3) 7% O(sub 2) (150 lb/hr) of trona (a natural sodium sesquicarbonate ore) injected through a rapid dispersion lance successfully controlled more than 50 percent of the acid gases. This should let facilities under 250 TPD meet the small plant guidelines for acid gas control. Various levels of PAC were injected along with the trona. 300 mg/dsm(sup 3) 7% O(sub 2) of PAC provides a comfortable margin between the emissions limitations achieved and both large and small plant regulatory guidelines for tetra- through octachlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) and mercury when the ESP is operated below 350(degrees)F. Bi-fluid nozzles were used to spray finely atomized water between the economizer outlet and ESP inlet to maintain temperatures in the desired 300-350(degrees)F range. Particulate and metals emissions limitations were met by this 400 ft(sup 2)/1,000 acft(sup 2) specific collector area (SCA), 3-field ESP. Both the water sprays and PAC improved ESP performance. The demonstration was successful. With dry PAC, acid gas reagent injection, and temperature reduction, MWC emissions guidelines for facilities smaller than 250 TPD can be reliably met. Everything except the large facilities SO(sub 2) and HCl guideline emissions limitations was achieved. Better acid gas control should be achievable with more reagent addition if the ESP is efficient enough to avoid violating particulate limits.