ICMGP - Conference Presentation

Abstract Information :

To reduce global mercury (Hg) pollution, the Minamata Convention on Mercury has been entered into force with five point source categories addressed, including coal-fired power plants (CFPPs), coal-fired industrial boilers (CFIBs), nonferrous metal smelters (NFMSs), cement production plants (CPPs) and waste incineration facilities (WIFs). As the largest anthropogenic Hg emitter, China shall establish an inventory of Hg emissions from relevant sources and evaluate the control effectiveness. To improve the capacity in these two aspects, we developed an integrated Dynamic Inventory for Mercury Emission (DIME) model in this study, and used it to establish inventories of anthropogenic Hg emissions in China during 2000?2020.
A sub-model was developed for estimating Hg emissions from CFPPs with the commonly used air pollution control device (APCD) combination of selective catalytic reduction systems (SCR), electrostatic precipitators (ESP) and wet flue gas desulfurization systems (WFGD), regarding the influence of coal quality on Hg removal efficiencies. For NFMSs, an advanced probabilistic mass flow sub-model with regard to the ?Hg removal compensation effect? between cascaded APCDs was developed for more accurate estimation of the overall Hg removal efficiency. Hg emissions from CFIBs were calculated by distinguishing boilers from kilns and furnaces in industrial coal combustion, with more reasonable Hg removal efficiencies considered. Upgraded APCDs due to the ultra-low emission retrofit were taken into consideration in Hg emission estimation for CPPs. The improved methodology used in the DIME model could provide an approach towards more accurate effectiveness evaluation for the Minamata Convention.
Results show that the total anthropogenic Hg emissions in China continuously increased from 373 Mg in 2000 to 515 Mg in 2010, and decreased to 366 Mg in 2020. The Hg emissions from NFMSs continued to decline from 2003 mainly due to the elimination of small-scale smelters and the enhanced SO2 emission control, but gradually leveled off in recent years. Benefited from the installation of high-efficiency APCDs, the Hg emissions from CFPPs and CFIBs showed a steady descending trend since 2008, especially for CFPPs during 2015 to 2017 owing to the ultra-low emission retrofit. Due to the sharp growth of the activity level and dust cycling in kiln systems, the Hg emissions from CPPs increased significantly from 2000 to 2014, and then gradually went down because of the co-benefit from newly built desulfurization devices. The continuous growth of Hg emissions from WIFs was due to the rapid increase in the amount of waste incineration.