Mercury emission from anthropogenic sources from Guizhou province, China, in 2006

Transcription

1 Mercury emission from anthropogenic sources from Guizhou province, China, in 2006 Li Guanghui 1, 2, Hao Jiming 1, WangShuxiao 1, Feng Xinbin 2 1 Department of Environmental Science and Engineering, Tsinghua University, Beijing , China 2 State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang , P. R. China May 11, 2010 Xi an

2 Content 1. Introduction 2. Method 3. Emission factors and emission amounts 4. Conclusion

3 1.Introduction 2006 Global Hg Emissions 12% 11% Residential Fuel Combustion Industrial Fuel Combustion Pow er Plant Fuel Combustion Transportation Fuel Combustion Biomass Burning 15% 18% Pig Iron Manufacture Cement Manufacture Copper Smelting Lead Smelting Zinc Smelting Artisanal Gold Extraction Mercury Mining 25% Caustic Soda Production Fig. 1 Distributions of global Hg emissions among major contributing source types (Streets et al.,2009)

4 1.Introduction China is the biggest anthropogenic mercury sources country in the world Fig. 2 The top ten anthropogenic mercury emission countries in the world (Pacyna et al.,2009)

5 1.Introduction Guizhou is the third anthropogenic mercury source in China China emitted about 540 t Hg to the atmosphere Fig. 3 Gridded total Hg emissions for the year 1999 (30 30 min resolution, unit: t yr -1 per grid cell )(Streets et al., 2005).

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7 1.Introduction Fig. 4 The distribution of Global mercury Belts

8 1.Introduction Fig. 5 The distribution of coal resource in China

9 1.Introduction Fig. 6 The average ph of rainfall in China

10 1.Introduction Fig.7 The major anthropogenic mercury sources in Guizhou

11 2. Method Table 1 Method for different anthropogenic mercury sources in our study Anthropogenic mercury sources Coal combustion Zn smelter method Flue gas test Mass balance Other sources Cite reference emission factors

12 2. 1 Coal combustion Capacity /MW Unit Total capacities/mw Plant Plant Plant All the coal-fired power plant were equipped with ESP and FGD. Two industrial boilers: one is 20 t h -1, the other is 75 t h -1, and they equipped with water dust scrubber.

13 2. 1 Coal combustion Hgp Hg Hg 2+ Hg Hg 0 Fig. 8 The sampling train of Ontario Hydro Method

14 2. 1 Coal combustion Fig. 9 The sampling sites in power plant

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16 2. 1 Coal combustion Table 2 Mercury in coal (ng g -1 ) Site Max. Min. Mean N Plant ±12 6 Plant ±19 8 Plant ±38 6 Industrial boiler ±49 6 Reference This study Industrial boiler ±35 6 Xinjiang Wang et al., 2000 Guizhou 200±30 9 Tang et al., Feng and Qiu, 2008b Zhang et al., 2007 China 150 USGS 200 Jiang, 2004

17 2. 1 Coal combustion Fig.10 Air pollutants concentration at the inlet and outlet of the air pollution control devices in plant 1 The total removing rate of total mercury is 58%, 36% by ESP and 34% by FGD, which fit well with the result from US EPA (36% in ESP ).

18 2. 1 Coal combustion Fig.11 Mercury concentration and speciation at inlet and outlet of air pollution control devices in plant 2 The removal efficiency of total mercury is 8% in ESP and 74% in FGD. The total removal efficiency is 76%.

19 2. 1 Coal combustion Fig.12 Mercury concentration and speciation at inlet and outlet of air pollution control devices in plant 3 The removal efficiency of total mercury is 39% in ESP and 29% in FGD. The total removal efficiency is 56%.

20 2. 1 Coal combustion Fig. 13 Hg removal efficiencies in coal-fired power plants

21 2. 1 Coal combustion Table 3 Mercury removal efficiencies by air pollution control devices in coal combustion Pollution sources unit Bottom fly ash water dust scrubber ESP ESP+FGD reference Coal-fired power plant anthracite Other coal type <100MW 30-50% 10%, >100MW 10%, 70% <100MW 30-50% 38% >100MW 38% 57% This work Industrial boiler <40% Residenti al boiler 17% Streets et al., 2005

22 2.2 Zn smelter Fig. 14 solid (liquid) sampling sites in the diagram of smelting process

23 2.2 Zn smelter Mass balance Hg emission = [ Hg] M feed n i= 1 F i (1) Where [Hg] represents Hg concentration in the feed Zn concentrate in Zn smelters, F i M feed i means the amounts of the feed Zn concentrate in Zn smelters. is the amounts of Hg retained by APCDs could be calculated from F i = [ Hg] by products M by products (2) Where [ Hg] represents Hg concentration in by-products in Zn smelters (calcine, dust, waste gas by products cleaning water, and sulfuric acid); M by products stands for the amounts of by-products produced

24 2.2 Zn smelter

25 2.2 Zn smelter Table 4 Mercury content in Zn ore (concentrate) and byproducts in Zn smelter Sample type Hg (mg kg -1 ) Zn (%) N Geomean±SD Geomean±SD Feed Zn concentrate industrial 57.9±7.42 ( ) 49.6±2.90 ( ) 6 Sulfide ore 66.8±41.4( ) 7 artisanal Oxide ore 13.4±19.4 ( ) 12 Smelting residue artisanal 0.18±0.14( ) 11 Dust (captured by cyclone collector) 5.40±2.20 ( ) 6 Dust (captured by electrostatic precipitator) Industrial 6.90±2.42 ( ) 6 Waste gas cleaning water 2.83±1.89 ( ) 9 Sulphuric acid 33.8±7.21 ( ) 9

26 3.Emission factors and emission amouts sources Sub-section unit coal combustion Oil combustion Zn smelter Hg mine Hg catalyst plant Table 5 Anthropogenic mercury emission factors and emission amounts in Guizhou Emission factor Product or consumption(t) Hg emission(t) industrial g/t coal Power plant g/t coal residential g/t coal reference This study g/t oil Streets et al., 2005 With H 2 SO 4 g/t Zn 12 This study Without H 2 SO 4 g/t Zn Li et al., 2008 industrial % artisanal % Li et al., 2009 Hg catalyst 3524 HgCl Tan et al., 1997 This study Hg metal % Tan et al., 1997 chlor-alkali industry 0.94 Cement production g/t Pacyna et al., 2009 Pit steel production g/t steel Pacyna et al., 2009 Total 50.86

27 3.Emission factors and emission amouts Fig. 15 The distribution of anthropogenic mercury emission in Guizhou

28 3.Emission factors and emission amouts Fig.16 The ratio of different sources to total emission

29 4.Conclusion The emissions of total mercury to atmosphere from major anthropogenic sources in Guizhou were estimated to be approximately tons. Mercury catalyst plants have been the largest source of anthropogenic emissions in this region contributing to about 32.90% to total emissions. Coal combustion released approximately tons to the atmosphere in 2006 contributing to about 29.12% total emissions,

30 4.Conclusion primary Zn production, mercury mine, cement production and chlor-alkali production contributed to about 19.58%, 12.29%, 3.53% and 1.84% o total emissions, respectively.

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