Apr 7, 2008 - Nonferrous metals smelting (zinc, copper, gold, and lead). See these two papers for description of the results presented here: Streets et al.
Mercury Emissions from Coal Combustion in China
David G. Streets Argonne National Laboratory Jiming Hao, Shuxiao Wang, Ye Wu Tsinghua University, Beijing
International Conference of the UNEP Global Partnership on Atmospheric Mercury Transport and Fate Research Rome, Italy, April 7-11, 2008
Argonne and Tsinghua collaboration
David G. Streets Argonne National Laboratory USA
Jiming Hao, Shuxiao Wang, Ye Wu Tsinghua University China
Project Sponsors: o
o
o
Melissa Chan, Mark Freeman, Tom Feeley DOE National Energy Technology Laboratory, USA
Thank you!
Conrad Chin, Marianne Bailey, Carl Mazza, Carey Jang US Environmental Protection Agency, USA
National Key Basic Research and Development Program of China 2
This presentation focuses on coal combustion, but there are many other significant sources of Hg in China: Other combustion sources
Fuel oil (gasoline, diesel, kerosene, and residual oil) Biofuels Grassland/Savanna/Forest fires Agricultural residue/Household waste burning Coal mines spontaneous burning Non-combustion sources (feedstock emissions only) Mercury mining Battery/Fluorescent lamp production Cement production Iron and steel production Caustic soda production Nonferrous metals smelting (zinc, copper, gold, and lead)
See these two papers for description of the results presented here: Streets et al., Atmos. Environ., 39, 7789-7806, 2005 Wu et al., Environ. Sci. Technol., 40, 5312-5318, 2006 3
Coal combustion comprises about 37% of total anthropogenic Hg emissions in China; the next talk discusses the other sources 800
Others 700
Non-ferrous Metal Smelting
600
500
400
300
200
100
20 03
20 02
20 01
20 00
19 99
19 98
19 97
19 96
0
19 95
Total Hg Emissions in China (Mg yr-1)
Coal Combustion
4
Coal is used everywhere in China, often in unfamiliar ways
5
Trends in raw coal consumption in China, 1995-2005
2.65 billion tons 2,500,000
2,000,000
Industrial use (feedstock) (17.8%) For briquettes (4.2%) For coal washing (7.1%) Other uses (combustion) (2.0%)
1,500,000 Residential use (-0.1%)
1,000,000
500,000
Coking (0.9%) Industrial use (combustion) (4.1%) Power plants (8.9%)
-
19 95 19 96 19 97 19 98 19 99 20 00 20 01 20 02 20 03 20 04 20 05
Total Raw Coal Consumption (1000 tons)
3,000,000
6
1,500,000 For briquettes
1.48 billion tons
Coking (8.2%)
1,200,000
Cleaned coal (coking) (8.5%) Cleaned coal (combustion) (4.8%)
900,000
Raw coal (coking) (0.9%) Raw coal (combustion) (4.1%)
600,000
300,000
05
20
04
20
03
20
02
20
01
20
00
20
99
19
98
19
97
19
96
19
95
-
19
Total Coal Consumption for Industrial Use (1000 tons)
Trends in industrial coal consumption in China, 1995-2005
7
Calculation procedure for mercury emissions from coal combustion in China Fractions released during combustion, reduced by control devices, and finally emitted (by species)
Spreadsheet is 107 x 32 (Fuel/Tech combinations x Provinces)
China Energy Statistics
Tech Splits
Hg in fuel
FREL
FRED
FSp
Fuel Use by Sector
Fuel Use by Sector, Technology
Total Hg
Hg released
Hg emitted
Hg(Sp) emitted
Hg to bottom ash
Hg to fly ash
8
A n B hu ei i j Fu ing G G jia ua a n ng ns G do u ua ng G ng ui x z i H hou ai H e i H nan lo e ng b jia ei H ng en H an u H be u i Ji na an n Ji gs an u gx i L N iao Jili ei n n M in o g N ng in ol Q gx in ia S gh S ha ai ha an nd xi S on h g S an ic x X hua i in n j Y ian u Zh nn g ej an ia ng
Mercury content of coal as mined (g Mg -1)
Mercury content of raw coal, as mined (g Mg-1) 0.6
0.5
National average, ~0.19 g Mg -1 National Average
0.4
0.3
0.2
0.1
0
9
Inter-province model of coal transportation flows
10
Examples of shares of boiler types with PM control devices for coal-fired power plants, by province, 1999 PC/scrubber
Stoker/scrubber
Stoker/cyclone
100%
80%
60%
40%
20%
nh u
Be i iji ng Fu jia n G G ans ua u ng do G ng ua ng G xi ui zh ou H He b ei e lo ng i jia ng H en an H ub ei H un a Ji n an gs u Ji an gx i
0%
A
Share of boiler types with PM control devices
PC/ESP
11
100.0% 80.0% ESP
60.0%
Scrubber Cyclone
40.0%
Power sector: now mostly ESPs
20.0% 0.0% 1995
1996
1997
Industrial sector: A mixture of wet PM scrubbers, cyclones, and no control
1998 Penetration of PM Control Device Installation
Penetration of PM Control Device Installation
Time development of the penetration of PM control devices
1999 2000
2001
2002
2003
60.0%
40.0%
20.0%
Scrubber Cyclone None
0.0% 1995
1996
1997
1998
1999
2000
2001
2002
2003
12
Mercury removal efficiencies of control technologies have been estimated, but there is no province, combustor, or time variation yet; many values are based on western experience Removal Efficiency (%) Case
Fuel/Combustor Type
PM Control
Provinces of China Anhui
31
Hard coal/PC
filter or ESP
33
Hard coal/PC
34
Beijing
Fujian
Gansu
Guangdong
30.6
30.6
30.6
30.6
30.6
scrubber
6.5
6.5
6.5
6.5
6.5
Hard coal/PC
cyclone
0.1
0.1
0.1
0.1
0.1
32
Hard coal/stoker
filter or ESP
30.6
30.6
30.6
30.6
30.6
35
Hard coal/stoker
scrubber
6.5
6.5
6.5
6.5
6.5
36
Hard coal/stoker
cyclone
0.1
0.1
0.1
0.1
0.1
85
Hard coal/cyclone
scrubber
6.5
6.5
6.5
6.5
6.5
86
Hard coal/cyclone
cyclone
0.1
0.1
0.1
0.1
0.1
37
Cleaned coal/PC
filter or ESP
30.6
30.6
30.6
30.6
30.6
39
Cleaned coal/PC
scrubber
6.5
6.5
6.5
6.5
6.5
40
Cleaned coal/PC
cyclone
0.1
0.1
0.1
0.1
0.1
38
Cleaned coal/stoker
filter or ESP
30.6
30.6
30.6
30.6
30.6
41
Cleaned coal/stoker
scrubber
6.5
6.5
6.5
6.5
6.5
42
Cleaned coal/stoker
cyclone
0.1
0.1
0.1
0.1
0.1
13
Trends in mercury emissions from coal combustion, 1995-2005 350
334 Mg 5.1% AGR
Industrial use (combustion) (4.9%)
300
Residential use (1.3%) Other uses (combustion) (2.0%)
250
200
150
100
50
05 20
04 20
03 20
02 20
01 20
00 20
99 19
98 19
97 19
96 19
95
0
19
Total Mercury Emissions from Coal Combustion (Mg)
Power plants (7.0%)
14
Uncertainty in Hg emissions from coal combustion, as 95% confidence intervals Mercury emissions (Mg) with uncertainty (95% confidence intervals)
500
400
300
200
100
19 95 19 96 19 97 19 98 19 99 20 00 20 01 20 02 20 03 20 04 20 05
0
We estimate that the uncertainty in emission estimates for coal combustion has remained stable over this period at ~ ±35% 15
1200
Best Estimates 1000 800 600 400 200 0
19 95 19 96 19 97 19 98 19 99 20 00 20 01 20 02 20 03
Total Hg emissions with uncertainty (95%confidence interval)
Uncertainty in total Hg emission estimates
In general, the uncertainty level has diminished over time (±78% down to ±44%). This is primarily attributed to decreased emissions from those Hg sources that have the largest uncertainty in both activity levels and emission factors, such as artisanal gold smelting, mercury mining, and battery/fluorescent lamp production. 16
Stochastic simulations are being developed to address uncertainties in Hg emission estimates when large sample sizes are available (e.g., Hg-in-coal)
17
A n B hu ei i j Fu in g G G jia ua a n n g ns G do u u n G an g g ui x z i H ho ai u H ei H nan lo e ng be ji i H an g en H an u H be Ji una i an n Ji gs an u gx Li Ji i N ao li n ei n M in o g N ng in ol Q gx i i Shngh a Sh a ai a an Sh nd xi an ong g Sh ha Si an i ch xi u Ti an Xi an n jin Yu jian Zh n n g e a N j ia n at ng io na l
Speciation Breakdown (%)
Speciation of Hg emitted from coal combustion (1999), by province 100%
80%
60%
40%
Hg0 Hg2+ Hg(p)
20%
0%
National average estimated to be: 64% Hg2+, 19% Hg(p), and 17% Hg0 18
Gridded Hg emissions from coal combustion in 1999 at 30 min resolution (Mg yr-1 per grid cell)
Total Hg (coal combustion sources) 0 - 0.0025 0.0025 - 0.1 0.1 - 0.4 0.4 - 1 1 - 10 10 - 32.5
19
Expected penetration of FGD on coal-fired power plants in China by 2010 and 2020, showing percentages by province 2010: 58% nationwide
2020: 67% nationwide
We assume the Hg removal efficiency of future plants to be: 74% (ESP+FGD)
20
Anticipated growth in electricity generation and coal use in China in 2010 and 2020 Coal
1,800
Electricity 3500
1,600 3000 1,400 2500
1,200 1,000
2000
800
1500
600 1000 400 500
200
20 20
10 20
03 20
02 20
01 20
00 20
99 19
98 19
97 19
19
96
0 95
-
Electricity Generation (billion kWh)
4000
19
Coal Consumption (million tons)
2,000
1) Nationwide, coal-based electricity is projected to increase at an annual rate of 7.5% in 2003-2010, and 3.8% in 2010-2020. 2) As a result, coal use reaches 1.29 billion tons in 2010 and 1.77 billion tons in 2020. 21
250
Planned FGD + SCR, ACI 200
150
Planned FGD
100
50
20 20
20 10
0
19 95 19 96 19 97 19 98 19 99 20 00 20 01 20 02 20 03
Hg Emissions from Power Plants, tons
The benefits of FGD in 2010, and of FGD and other controls (like SCR and a little ACI) by 2020, on mercury emissions from coalfired power plants: Emissions can potentially be stabilized
22
Research question: Can we reconcile emission estimates with measurements of the Hg flux leaving Asia?
Guizhou sites [Feng et al., JGR, 110, D14306, 2005, etc.]
Aircraft measurements and modeling during ACE-Asia campaign [Pan et al., JGR, 111, D07109, 2006; Friedli et al., JGR, 109, D19S25, 2004]
Okinawa site [Jaffe et al., Atmos. Environ., 39, 3029, 2005]
23
Future plans Refine estimates of anthropogenic Hg emissions in China,
including the important contributions from zinc smelters. Incorporate stack test measurements that are now becoming available. Estimate future Hg emissions under alternative scenarios of growth and the penetration of new production and emission control technologies. Incorporate uncertainty explicitly into our calculations through stochastic modeling. Support the Hg atmospheric modeling community and work to reconcile flux measurements with model and emissions estimates, factoring in new information on natural sources and re-emission.
24