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Atmospheric Lead Emissions from Coal-Fired Power Plants with Different Boilers and APCDs in Guizhou, Southwest China
journal contribution
posted on 2019-11-13, 15:17 authored by Xinyu Li, Xiangyang Bi, Zhonggen Li, Leiming Zhang, Shan Li, Ji Chen, Xinbin Feng, Xuewu FuLead (Pb) emissions into the atmosphere from anthropogenic
sources
have attracted considerable attention due to lead’s high toxicity
and associated human health and environmental impacts. Pb emission
inventories need to be updated considering the development of modern
industry as well as the transformation and upgrading of industrial
equipment in recent years. Coal-fired power plants (CFPPs) have been
an important source of atmospheric Pb emission in China since the
late 1990s, while tremendous advantages have been achieved in the
air-pollution control devices (APCDs) in the most recent two decades.
In this study, Pb emissions from eight CFPPs, two of which have circulating
fluidized bed boilers (CFB) and the others have pulverized coal fired
boilers (PC), in Guizhou province, Southwest China were investigated.
Solid samples including feed fuel (coal, gangue, and coal slime),
limestone, bottom ash, fly ash, and gypsum, as well as stack flue
gas samples were simultaneously collected for determining the internal
partitioning behavior and the atmospheric emissions of Pb from these
CFPPs. Pb concentrations of feed coal, limestone, bottom ash, fly
ash, gypsum, and stack flue gas were in the range of 10.17–30.94,
0.36–3.08, 7.75–27.10, 33.56–73.16, 0.34–2.18
mg·kg–1, and 0.33–1.58 μg·Nm−3, respectively. The mass balance (output/input) ratio
of Pb was in the range of 83.73–124.95%, with input dominated
by the feed coal (95.89–99.96%) and output by fly ash (73.17–97.54%),
followed by bottom ash (2.16–26.76%) and atmospheric emissions
(0.01–0.08%). More Pb ended up in PC fly ash (88.89–97.54%)
than CFB fly ash (73.17–81.19%), but an opposite trend was
found in the bottom ash for different boilers. Pb emission factors
(EMFs) could not be differentiated significantly between PC and CFB
boilers, which were in the range of 2.32–10.67 mg·t–1 fuel, 1.28–6.51 μg·(kW·h)−1, or 0.12–0.51 g·TJ–1. Atmospheric Pb emissions from Guizhou’s CFPP were estimated
to be 430 ± 163 kg·y–1 in 2017, much lower
than previously reported values.