scholarly journals Mercury emission and speciation of coal-fired power plants in China

2009 ◽  
Vol 9 (6) ◽  
pp. 24051-24083 ◽  
Author(s):  
S. Wang ◽  
L. Zhang ◽  
G. Li ◽  
Y. Wu ◽  
J. Hao ◽  
...  
Keyword(s):  
Flue Gas ◽  
Power Plants ◽  
Total Mercury ◽  
Bottom Ash ◽  
Field Measurements ◽  
Elemental Mercury ◽  
Control Device ◽  
Mercury Emission ◽  
Mercury Emissions ◽  
Removal Efficiencies

Abstract. Comprehensive field measurements are needed to understand the mercury emissions from Chinese power plants and to improve the accuracy of emission inventories. Characterization of mercury emissions and their behavior were measured in six typical coal-fired power plants in China. During the tests, the flue gas was sampled simultaneously at inlet and outlet of selective catalyst reduction (SCR), electrostatic precipitators (ESP), and flue gas desulfurization (FGD) using the Ontario Hydro Method (OHM). The pulverized coal, bottom ash, fly ash and gypsum were also sampled in the field. Mercury concentrations in coal burned in the measured power plants ranged from 17 to 385 μg/kg. The mercury mass balances for the six power plants varied from 87 to 116% of the input coal mercury for the whole system. The total mercury concentrations in the flue gas from boilers were at the range of 1.92–27.15 μg/m3, which were significantly related to the mercury contents in burned coal. The mercury speciation in flue gas right after the boiler is influenced by the contents of halogen, mercury, and ash in the burned coal. The average mercury removal efficiencies of ESP, ESP plus wet FGD, and ESP plus dry FGD-FF systems were 24%, 73% and 66%, respectively, which were similar to the average removal efficiencies of pollution control device systems in other countries such as US, Japan and South Korea. The SCR system oxidized 16% elemental mercury and reduced about 32% of total mercury. Elemental mercury, accounting for 66–94% of total mercury, was the dominant species emitted to the atmosphere. The mercury emission factor was also calculated for each power plant.

scholarly journals Mercury emission and speciation of coal-fired power plants in China

2010 ◽  
Vol 10 (3) ◽  
pp. 1183-1192 ◽  
Author(s):  
S. X. Wang ◽  
L. Zhang ◽  
G. H. Li ◽  
Y. Wu ◽  
J. M. Hao ◽  
...  
Keyword(s):  
Flue Gas ◽  
Power Plants ◽  
Total Mercury ◽  
Catalytic Reduction ◽  
Bottom Ash ◽  
Field Measurements ◽  
Elemental Mercury ◽  
Mercury Emission ◽  
Mercury Emissions ◽  
Removal Efficiencies

Abstract. Comprehensive field measurements are needed to understand the mercury emissions from Chinese power plants and to improve the accuracy of emission inventories. Characterization of mercury emissions and their behavior were measured in six typical coal-fired power plants in China. During the tests, the flue gas was sampled simultaneously at inlet and outlet of Selective Catalytic Reduction (SCR), electrostatic precipitators (ESP), and flue gas desulfurization (FGD) using the Ontario Hydro Method (OHM). The pulverized coal, bottom ash, fly ash and gypsum were also sampled in the field. Mercury concentrations in coal burned in the measured power plants ranged from 17 to 385 μg/kg. The mercury mass balances for the six power plants varied from 87 to 116% of the input coal mercury for the whole system. The total mercury concentrations in the flue gas from boilers were at the range of 1.92–27.15 μg/m3, which were significantly related to the mercury contents in burned coal. The mercury speciation in flue gas right after the boiler is influenced by the contents of halogen, mercury, and ash in the burned coal. The average mercury removal efficiencies of ESP, ESP plus wet FGD, and ESP plus dry FGD-FF systems were 24%, 73% and 66%, respectively, which were similar to the average removal efficiencies of pollution control device systems in other countries such as US, Japan and South Korea. The SCR system oxidized 16% elemental mercury and reduced about 32% of total mercury. Elemental mercury, accounting for 66–94% of total mercury, was the dominant species emitted to the atmosphere. The mercury emission factor was also calculated for each power plant.

Test and Research for Mercury Emission of Boilers in 700 MW Units

2014 ◽  
Vol 672-674 ◽  
pp. 1514-1518
Author(s):  
Fa Sheng Liu ◽  
Yong Lu Zhong ◽  
Rui Xu ◽  
Lin Guo Chen ◽  
Yong Jun Xia
Keyword(s):  
Low Temperature ◽  
Flue Gas ◽  
Power Plants ◽  
Combustion Products ◽  
Mercury Content ◽  
Jiangxi Province ◽  
Mercury Emission ◽  
Large Power ◽  
Mercury Emissions ◽  
Before And After

In this paper, the conversion process and the existing forms of mercury in the course of coal firing are first analyzed, and different methods to measure mercury are introduced; To assess the mercury emission levels of boilers in large power plants, through testing the mercury content in combustion products of the boiler in 700 MW unit under different loads in one power plant of Jiangxi Province, we analyzed the formation distribution of mercury emissions and the effect of low temperature economizer on the mercury concentration before and after the ESP, and acquired the mercury emission characteristics of 700 MW boiler. In study, we found that mercury in the coal burnt in 700 MW boiler was mainly discharged in the form of gas, with a small amount existing in burnt solids. The change of gaseous mercury before and after the ESP is not obvious, but the concentration of bivalent mercury is higher than that of zero-valent mercury; and more than 90% of the particulate mercury is removed. The low temperature economizer in operation can obviously reduce the concentration of mercury in flue gas at the ESP outlet by 30.8%.

Research on Mercury Emissions Regularity and Adsorbing Mercury by Activated Carbon in Coal-fired Power Plants

2011 ◽  
Vol 284-286 ◽  
pp. 301-304 ◽  
Author(s):  
Zhang Xian Liu ◽  
Pei Pei Sun ◽  
Song Tao Chen ◽  
Li Juan Shi
Keyword(s):  
Activated Carbon ◽  
Power Plant ◽  
Removal Efficiency ◽  
Flue Gas ◽  
Power Plants ◽  
Elemental Mercury ◽  
Mercury Pollution ◽  
Anthropogenic Source ◽  
Modified Activated Carbon ◽  
Mercury Emissions

The coal-fired power plant is the main anthropogenic source of mercury pollution. The mercury in flue gas exists as elemental mercury(Hg0), oxidizing state mercury(Hg2+) and particulate mercury(Hgp). Mercury speciation distribution in flue gas was influenced and controled by the factors including conditions of ignition, desulphurization or denitration and Based on the investigation of coal-fired power plant technologies of removing Hg, this research uses the modified activated carbon (MAC) and studies its removal efficiency. Result indicates that the uptake of Hg by MAC was﹥90%.

scholarly journals Uncertainties in estimating mercury emissions from coal-fired power plants in China

2009 ◽  
Vol 9 (6) ◽  
pp. 23565-23588 ◽  
Author(s):  
Y. Wu ◽  
D. G. Streets ◽  
S. X. Wang ◽  
J. M. Hao
Keyword(s):  
Power Plants ◽  
Total Mercury ◽  
Anthropogenic Activities ◽  
Mercury Content ◽  
Distribution Functions ◽  
Mercury Removal ◽  
Mercury Emission ◽  
Mercury Emissions ◽  
Uncertainty Range ◽  
Best Estimate

Abstract. A detailed multiple-year inventory of mercury emissions from anthropogenic activities in China has been developed. Coal combustion and nonferrous metals production continue to be the two leading mercury sources in China, together contributing ~80% of total mercury emissions. Within our inventory, a new comprehensive sub-module for estimation of mercury emissions from coal-fired power plants in China is constructed for uncertainty case-study. The new sub-module integrates up-to-date information regarding mercury content in coal by province, coal washing and cleaning, coal consumption by province, mercury removal efficiencies by control technology or technology combinations, etc. Based on these detailed data, probability-based distribution functions are built into the sub-module to address the uncertainties of these key parameters. The sub-module incorporates Monte Carlo simulations to take into account the probability distributions of key input parameters and produce the mercury emission results in the form of a statistical distribution. For example, the best estimate for total mercury emissions from coal-fired power plants in China in 2003 is 90.5 Mg, with the uncertainty range from 57.1 Mg (P10) to 154.6 Mg (P90); and the best estimate for elemental mercury emissions is 43.0 Mg, with the uncertainty range from 25.6 Mg (P10) to 75.7 Mg (P90). The results further indicate that the majority of the uncertainty in mercury emission estimation comes from two factors: mercury content in coal and mercury removal efficiency.

scholarly journals Uncertainties in estimating mercury emissions from coal-fired power plants in China

2010 ◽  
Vol 10 (6) ◽  
pp. 2937-2946 ◽  
Author(s):  
Y. Wu ◽  
D. G. Streets ◽  
S. X. Wang ◽  
J. M. Hao
Keyword(s):  
Power Plants ◽  
Total Mercury ◽  
Mercury Content ◽  
Distribution Functions ◽  
Stochastic Simulations ◽  
Mercury Removal ◽  
Mercury Emission ◽  
Mercury Emissions ◽  
Uncertainty Range ◽  
Best Estimate

Abstract. A detailed multiple-year inventory of mercury emissions from anthropogenic activities in China has been developed. Coal combustion and nonferrous metals production continue to be the two leading mercury sources in China, together contributing ~80% of total mercury emissions. However, many uncertainties still remain in our knowledge of primary anthropogenic releases of mercury to the atmosphere in China. In situations involving large uncertainties, our previous mercury emission inventory that used a deterministic approach could produce results that might not be a true reflection of reality; and in such cases stochastic simulations incorporating uncertainties need to be performed. Within our inventory, a new comprehensive sub-module for estimation of mercury emissions from coal-fired power plants in China is constructed as an uncertainty case study. The new sub-module integrates up-to-date information regarding mercury content in coal by province, coal washing and cleaning, coal consumption by province, mercury removal efficiencies by control technology or technology combinations, etc. Based on these detailed data, probability-based distribution functions are built into the sub-module to address the uncertainties of these key parameters. The sub-module incorporates Monte Carlo simulations to take into account the probability distributions of key input parameters and produce the mercury emission results in the form of a statistical distribution. For example, the best estimate for total mercury emissions from coal-fired power plants in China in 2003 is 90.5 Mg, with the uncertainty range from 57.1 Mg (P10) to 154.6 Mg (P90); and the best estimate for elemental mercury emissions is 43.0 Mg, with the uncertainty range from 25.6 Mg (P10) to 75.7 Mg (P90). The results further indicate that the majority of the uncertainty in mercury emission estimation comes from two factors: mercury content of coal and mercury removal efficiency.

The centralized control of elemental mercury emission from the flue gas by a magnetic rengenerable Fe–Ti–Mn spinel

2015 ◽  
Vol 299 ◽  
pp. 740-746 ◽  
Author(s):  
Yong Liao ◽  
Shangchao Xiong ◽  
Hao Dang ◽  
Xin Xiao ◽  
Shijian Yang ◽  
...  
Keyword(s):  
Flue Gas ◽  
Elemental Mercury ◽  
Centralized Control ◽  
Mercury Emission

scholarly journals Mercury Migration Behavior from Flue Gas to Fly Ashes in a Commercial Coal-Fired CFB Power Plant

Energies ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1040 ◽  
Author(s):  
Xiaohang Li ◽  
Yang Teng ◽  
Kai Zhang ◽  
Hao Peng ◽  
Fangqin Cheng ◽  
...  
Keyword(s):  
Fly Ash ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Flue Gas ◽  
Power Plants ◽  
Bottom Ash ◽  
Migration Behavior ◽  
Boiler Unit ◽  
Cfb Boiler

Mercury (Hg) emissions from coal-fired power plants are of increasing concern around the world. In this study, field tests were carried out to understand the Hg emission characteristics and its migration behaviors in a commercial CFB boiler unit with the electricity generation capacity of 25 MW. This boiler is equipped with one electrostatic precipitator (ESP) and two fabric filters (FFs) in series for removing particulates from the flue gas. The EPA 30B method was used for simultaneous flue gas Hg sampling at the inlet of the ESP and the outlet of the second FF. The Hg mass balance in the range of 104.07% to 112.87% was obtained throughout the CFB unit by measuring the Hg contents in the feed fuel, the fly ash and the bottom ash, as well as in the flue gas at the outlet of the particulate control device (PCD) system. More than 99% of Hg contained in the feed fuel was captured by the fly ash, whilst less than 1% of Hg was remained in the bottom ash or the flue gas after passing the PCD system. The gaseous Hg obviously migrated from the flue gas to the fly ash in the air pre-heater, where the flue gas temperature decreased from 250 °C at the inlet to 120 °C at the outlet. Other gaseous Hg migrated from the flue gas to the fly ash in the PCD system, as the Hg concentrations in the flue gas ranged from 3.14 to 4.14 μg/m3 at the inlet of the ESP and ranged from 0.30 to 0.36 μg/m3 at the outlet of the second FF. The average Hg contents in the fly ash samples collected from the ESP, the first FF and the second FF were 912.3, 1313.6 and 1464.9 ng/g, respectively, while the mean particle diameters of these fly ash samples tend to decrease along the flow pass in the PCD system. Compared to large fly ash particles, smaller fly ash particles exhibit higher Hg capture performance due to their high unburned carbon (UBC) content and large specific surface area. The migration of gaseous Hg from the flue gas to the fly ash downstream of the CFB boiler unit was easier than that downstream of the PC boiler unit due to high UBC content and specific surface area.

Study of Mercury Re-Emission from Simulated Wet Flue Gas Desulfurization Liquors

2012 ◽  
Vol 610-613 ◽  
pp. 2033-2037 ◽  
Author(s):  
Yu Ze Jiang ◽  
Chuan Min Chen ◽  
Li Xing Jiang ◽  
Song Tao Liu ◽  
Bin Wang
Keyword(s):  
Flue Gas ◽  
Total Mercury ◽  
Elemental Mercury ◽  
Operating Conditions ◽  
Flue Gas Desulfurization ◽  
Emission Rates ◽  
Ph Values ◽  
Mercury Control ◽  
Forced Oxidation ◽  
Reducing Substances

Hg2+captured by wet flue gas desulfurization (WFGD) systems can easily be reduced by reducing substances such as S(IV) (SO32-or HSO3-) and results in emissions of elemental mercury (Hg0). The re-emission of Hg0would lead to a damping of the total mercury removal efficiency by WFGD systems. The effects of the operating conditions, which included the pH, temperature, Cl-concentrations and oxygen concentrations, on Hg0re-emission from WFGD liquors was carried out. The experimental results indicated that the Hg0re-emission rate from WFGD liquors increased as the operational temperatures and pH values increased. The Hg0re-emission rates decreased as the O2concentration of flue gas and Cl-concentration of WFGD liquors increased. So the Hg0re-emission from WFGD system can be reduced or slowed by decreasing the temperature and pH, or by using forced oxidation. The present findings could be valuable for industrial application of characterizing and optimizing mercury control in WFGD systems.

To MACT or Not to MACT: Mercury Emissions From Waste-to-Energy and Coal-Fired Power Plants

2005 ◽  
Author(s):  
Nickolas J. Themelis ◽  
Nada Assaf-Anid
Keyword(s):  
Capital Investment ◽  
Power Plants ◽  
Elemental Mercury ◽  
Waste To Energy ◽  
Electricity Production ◽  
Anthropogenic Source ◽  
Mercury Emissions ◽  
Fabric Filter ◽  
The Cost ◽  
The U.S

During the combustion of fuel in Waste-to-Energy (WTE) and coal-fired power plants, all of the mercury input in the feed is volatilized. The primary forms of mercury in stack gas are elemental mercury (Hg0) and mercuric ions (Hg2+) that are predominantly found as mercuric chloride. The most efficient way to remove mercury from the combustion gases is by means of dry scrubbing, followed by activated carbon injection and a fabric filter baghouse. Back in 1988, the U.S. WTE power plants emitted about 90 tons of mercury (Hg). By 2003, implementation of the EPA Maximum Achievable Control Technology (MACT) standards, at a cost of one billion dollars, reduced WTE mercury emissions to less than one ton of mercury. EPA now considers coal-fired power plants to be the largest remaining anthropogenic source of mercury emissions. Approximately 800 million short tons of coal, containing nearly 80 short tons of Hg are combusted annually in the U.S. for electricity production. About 40% of this amount is presently captured in the gas control systems of coal-fired utilities. Since the concentration of mercury in U.S. coal is ten times lower than in the MSW feed and the volume of gas to be cleaned 55 times higher, the cost of implementing MACT by the U.S. coal-fired utilities is estimated to be about $25 billion. However, when this retrofit cost is compared to the total capital investment and revenues of the two industries, it is concluded that MACT should be affordable. Per kilogram of mercury to be captured, the cost of MACT implementation by the utilities will be twenty times higher than was for the WTE industry. However, implementation of MACT by the utilities will also reduce the emissions of other gaseous contaminants and of particulate matter.

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