Experimental Study on Co-Firing of Coal and Brewery Wastewater Sludge

Abstract

The environmental pollution and high energy consumption caused by the coal-dominated energy structure in China have been the focus of attention for a long time. The co-firing of biomass with coal can save coal resources and realize effective utilization of biomass. In this paper, brewery wastewater sludge (SD) and bituminous coal (BC) were blended for an experimental study which aimed to provide basic experimental data and operational guidance as a reference for practical application in power plants. The co-firing characteristics of sludge and bituminous coal were studied. The results show that the burnout temperature and ignition temperature decrease with an increase in the sludge blending ratio. The Comprehensive Combustion Index (CCI) first rises, then decreases, reaching a maximum at about 15%. Compared with the atmosphere with 79% N2/21% O2, under the 79% CO2/21% O2 atmosphere, ignition is delayed and the burnout temperature is higher. Under an O2/CO2 atmosphere, as the O2 concentration improves, the thermo-gravimetric (TG) curve shifts to the low-temperature region, the burnout temperature drops significantly, and the comprehensive combustion characteristics are improved. With an increment of the heating rate, the curve of TG analysis shifts to the high-temperature region and the CCI increases. This study could provide helpful information on practical blending in coal-fired power plants for energy savings and emission reductions.