VOC Emissions Characteristics and Cooperative Control by Combustion Adjustment and APCDs in Supercritical Coal-Fired Power Plants

This study examined volatile organic compound (VOC) emission characteristics in three supercritical coal-fired power plants (660 MW, 600 MW, and 330 MW units), with five tasks: the effect of load, excess air ratio, combustion flame location (adjust the burners), air pollution control device (APCD) operational scenarios, and co-firing with biomass (10%) and sludge (10%), all of which were carried out in situ. Each task included two similar setups on the boiler and APCDs for comparison. A 1.4 MW pilot scale was included to provide the most challenging tasks, which were difficult to conduct in the power plant. Around 60 to 70% of VOC was reduced by optimizing the boiler combustion conditions, which was most influenced by increasing the flame center height and adjusting the secondary air ratio. The rest (30-40%) of the VOC entered the APCD's system from the boiler, and the central portion of the VOC in the tail gas was effectively oxidized through the catalytic oxidation process in the SCR system. The ESP had negligible removal effects on VOC, and the high-voltage discharge enhanced the re-emission of VOCs from fly ash. Thus, combustion condition optimizations combined with APCDs could synergistically remove over 90% of VOCs in most power plants. In addition, the blending of biomass and sludge will increase the production of VOCs. The study is crucial for achieving clean coal power production and significantly reducing VOC emissions.