Synergistic Removal Effects of Ultralow Emission Air Pollution Control Devices on Trace Elements in a Coal-Fired Power Plant

Abstract

The effects of air pollution control devices (APCDs) such as selective catalytic reduction systems, electrostatic precipitators (ESPs), seawater desulfurization (SWFGD) units, and wet ESPs (WESP) on the ultralow emissions of trace elements (TEs) in a 300 MW pulverized coal boiler system are studied to reveal the removal of TEs (As, Se, and Pb) in these facilities. The results show that the average synergistic removal efficiencies of As, Se, and Pb in the studied power plant are 97.26, 94.07, and 95.49%, respectively. The emission concentration of As, Se, and Pb did not exceed 0.17, 0.67, and 4.23 μg/m3, respectively. ESPs can capture a great part of As and Pb; most of the Se is removed in the SWFGD system and WESP. The flue gas temperature decreasing in the air preheater (APH) and flue gas cooling system facilitates particulate TE removal in the ESP. Seawater in the SWFGD system promotes the dissolution and removal of unfilterable TEs, making the SWFGD system more efficient than conventional WFGDs under some working conditions. The influence of the boiler load and sulfur content of coals on the migration and transformation characteristics of TEs has also been systematically studied. Burning coal with a higher sulfur content can improve the synergistic removal of Pb, and working under a low boiler load is beneficial to the synergistic removal of As, Se, and Pb by APCDs of power plants. Hopefully, this study can provide a reference for the removal of TEs under various operating conditions in power plants with different APCDs.

Review of Migration, Transformation, and Control of Volatile Components during Desulfurization Wastewater Evaporation: Advances and Perspectives

“…67 The long-term operation process bears the potential risk of continuous cyclic enrichment of volatile components in desulfurization wastewater. Research 19,54,68,69 indicates that the overall percentage removal of heavy metals from flue gas by WFGD was >86%, with the removal of 60−90% of Hg and >96% of As and the majority of Se from flue gas. Meanwhile, limestone is an essential source of elements such as arsenic and nickel in FGD wastewater.…”

Ensemble Prediction Model for Dust Collection Efficiency of Wet Electrostatic Precipitator

“…In addition, According to a study conducted by Othman et al, Wet Electrostatic Precipitators (WESPs) demonstrate higher dust collection efficiency compared to other types of air pollution control technologies such as baghouses or cyclones. The research indicated that WESPs can achieve a collection efficiency of up to 99.99%, while baghouses and cyclones typically attain collection efficiencies of up to 99% and 95%, respectively [16].…”