Non-Negligible Stack Emissions of Noncriteria Air Pollutants from Coal-Fired Power Plants in China: Condensable Particulate Matter and Sulfur Trioxide

Abstract

In this study, we investigated the emission characteristics of condensable particulate matter (CPM) and sulfur trioxide (SO3) simultaneously through ammonia-based/limestone-based wet flue gas desulfurization (WFGD) from four typical coal-fired power plants (CFPPs) by conducting field measurements. Stack emissions of filterable particulate matter (FPM) all meet the Chinese ultralow emission (ULE) standards, whereas CPM concentrations are prominent (even exceed 10 mg/Nm3 from two CFPPs). We find that NH4 + and Cl– increase markedly through the ammonia-based WFGD, and SO4 2– is generally the main ionic component, both in CPM and FPM. Notably, the occurrence of elemental Se in FPM and CPM is significantly affected by WFGD. Furthermore, the established chemical profiles in FPM and CPM show a distinct discrepancy. In CPM, the elemental S mainly exists as a sulfate, and the metallic elements of Na, K, Mg, and Ca mainly exist as ionic species. Our results may indicate that not all SO3 are included in CPM and they co-exist in stack plume. With the substantial reduction of sulfur dioxide (SO2), S distributed in SO3, CPM, and FPM becomes non-negligible. Finally, the emission factors of CPM and SO3 under typical ULE technical routes fall in the ranges of 74.33–167.83 and 48.76–86.30 g/(t of coal) accordingly.

Direct Observation of Sulfate Explosive Growth in Wet Plumes Emitted From Typical Coal‐Fired Stationary Sources

“…10.1029/2020GL092071 4 of 9 (Feng et al, 2018;G. Wang et al, 2020;Wu et al, 2020). Most of these reported values obtained by the dry impinge method are commonly lower than the concentration of the increased sulfate as measured in the CFPP plumes.…”

“…Although the concentration of SO 2 is strictly controlled by the integrated system of wet flue gas desulfurization (WFGD) and wet electrostatic precipitation (WESP), SO 2 is still the predominant soluble gas in the wet plumes (also known as white plumes) (Seigneur et al., 2011; Wu et al., 2020), which surrounded by saturated water vapor will immediately condense into solid and liquid particles in the elevated stack plumes (Feng et al., 2018). The favorable conditions for SO 2 to dissolve in droplets and generate S (IV) include (1) a large number of microdroplets, (2) a high SO 2 uptake coefficient at a low temperature, (3) a long uptake response time provided by the large stack space, and (4) a relatively uniform distribution of droplets and SO 2 .…”

Experimental Study on the Removal of Low-Concentration SO3 by Trona at Medium Temperatures

“…When the adsorbent is injected inside the SCR or between SCR and APH, the SO 3 formed in the furnace and SCR can be removed . The application of this technology can solve problems such as APH corrosion and has greater advantages than other methods; hence, it is the focus of the current research. , In industrial applications, the adsorbent material is the key to this technique. Although calcium- and sodium-based materials are usually chosen, , there are many defects in practical applications.…”

A Neural-Network-Based Method for Ash Fouling Prediction of Heat Transfer Surface in Coal-Fired Power Plant Boiler

“…New energy generation, such as wind and solar energy, has a promising future, but thermal power generation is still the power supply mode in most countries at the present stage [1][2]. As China's efforts to save energy and reduce emissions increase, the requirements for controlling pollution emissions and reducing energy consumption are also increasing [3][4]. As the main device of thermal power generation, coal-fired boilers shoulder the important task of converting thermal energy into electrical energy.…”