SOx REMOVAL EFFICIENCY UPGRADE BY DBA ADDITION IN THE JBR FGD PLANTS

Abstract

Because the national ambient air quality standards in Korea is getting strict, the emission standards of air pollutants at sources also will be enforced to reduce total air emissions. Therefore, each power plant, which is one of huge emission sources of air pollutants, needs to establish new air pollution control (APC) facilities or improve the existing APC facilities to reduce the total emissions and to satisfy the strict emission regulations. Especially, emission reduction of SOx in power plants in Korea is strictly required. The existing SOx control facilities, JBR FGD plants, for the removal of SOx in flue gas have faced the removal efficiency decrease and scale problems according to the continuous operation of the control facilities. In order to solve these problems, this study employed a method to increase alkalinity of the scrubbing medium by adding dibasic acid (DBA), which is obtained as by-products generated from plants synthesizing adipic acid. The SOx removal efficiency, the purity of CaCO3, and COD of the wastewater were measured to identify the improvement effects by addition of DBA, a minimum concentration of 150ppm, for 2hr in a day in the scrubber attached to the large-scale power plants (400MW×3). The SOx removal efficiency and the purity of CaCO3 by increasing the alkalinity of the scrubbing medium increased as much as 2 - 5% and 1 - 2%, respectively. However, the COD of the wastewater produced from the SOx removal facilities increased from 10 - 15 mg/l to 15 - 35 mg/l and the erosion problems in the injection pump and duct occurred. We are performing the further experiments measuring the pollutant removal effects as a function of DBA concentration in the large-scale plants. Through increasing alkalinity of the scrubbing medium by adding DBA in the SOx removal reactors (scrubbers) attached to the FGD Plants, it was possible to reduce the electric power expense and air emissions of SOx.