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.

scholarly journals Investigation on Mercury Reemission from Limestone-Gypsum Wet Flue Gas Desulfurization Slurry

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Chuanmin Chen ◽  
Songtao Liu ◽  
Yang Gao ◽  
Yongchao Liu
Keyword(s):  
Removal Efficiency ◽  
Flue Gas ◽  
Industrial Application ◽  
Operating Conditions ◽  
Flue Gas Desulfurization ◽  
Mercury Removal ◽  
Slight Effect ◽  
Ph Values ◽  
Mercury Control ◽  
Partitioning Behavior

Secondary atmospheric pollutions may result from wet flue gas desulfurization (WFGD) systems caused by the reduction of Hg2+to Hg0and lead to a damping of the cobenefit mercury removal efficiency by WFGD systems. The experiment on Hg0reemission from limestone-gypsum WFGD slurry was carried out by changing the operating conditions such as the pH, temperature, Cl−concentrations, and oxygen concentrations. The partitioning behavior of mercury in the solid and liquid byproducts was also discussed. The experimental results indicated that the Hg0reemission rate from WFGD slurry increased as the operational temperatures and pH values increased. The Hg0reemission rates decreased as the O2concentration of flue gas and Cl−concentration of WFGD slurry increased. The concentrations of O2in flue gas have an evident effect on the mercury retention in the solid byproducts. The temperature and Cl−concentration have a slight effect on the mercury partitioning in the byproducts. No evident relation was found between mercury retention in the solid byproducts and the pH. The present findings could be valuable for industrial application of characterizing and optimizing mercury control in wet FGD systems.

Artificial Intelligence-Based Emission Reduction Strategy for Limestone Forced Oxidation Flue Gas Desulfurization System

2020 ◽  
Vol 142 (9) ◽  
Author(s):  
Ghulam Moeen Uddin ◽  
Syed Muhammad Arafat ◽  
Waqar Muhammad Ashraf ◽  
Muhammad Asim ◽  
Muhammad Mahmood Aslam Bhutta ◽  
...  
Keyword(s):  
Flue Gas ◽  
Power Plants ◽  
Operating Conditions ◽  
Process Models ◽  
Flue Gas Desulfurization ◽  
Optimum Operating ◽  
Input Control ◽  
Network Process ◽  
Coal Power Plants ◽  
Forced Oxidation

Abstract The emissions from coal power plants have serious implication on the environment protection, and there is an increasing effort around the globe to control these emissions by the flue gas cleaning technologies. This research was carried out on the limestone forced oxidation (LSFO) flue gas desulfurization (FGD) system installed at the 2*660 MW supercritical coal-fired power plant. Nine input variables of the FGD system: pH, inlet sulfur dioxide (SO2), inlet temperature, inlet nitrogen oxide (NOx), inlet O2, oxidation air, absorber slurry density, inlet humidity, and inlet dust were used for the development of effective neural network process models for a comprehensive emission analysis constituting outlet SO2, outlet Hg, outlet NOx, and outlet dust emissions from the LSFO FGD system. Monte Carlo experiments were conducted on the artificial neural network process models to investigate the relationships between the input control variables and output variables. Accordingly, optimum operating ranges of all input control variables were recommended. Operating the LSFO FGD system under optimum conditions, nearly 35% and 24% reduction in SO2 emissions are possible at inlet SO2 values of 1500 mg/m3 and 1800 mg/m3, respectively, as compared to general operating conditions. Similarly, nearly 42% and 28% reduction in Hg emissions are possible at inlet SO2 values of 1500 mg/m3 and 1800 mg/m3, respectively, as compared to general operating conditions. The findings are useful for minimizing the emissions from coal power plants and the development of optimum operating strategies for the LSFO FGD system.

The Study on the Performance of Wet Limestone-Gypsum Flue Gas Mercury Removal Additive

2013 ◽  
Vol 448-453 ◽  
pp. 608-612
Author(s):  
Li Bao Yin ◽  
Qi Sheng Xu ◽  
Jiang Jun Hu ◽  
Yang Heng Xiong ◽  
Si Wei Chen
Keyword(s):  
Removal Efficiency ◽  
Flue Gas ◽  
Total Mercury ◽  
Elemental Mercury ◽  
Flue Gas Desulfurization ◽  
Mercury Removal ◽  
Additive Increase ◽  
Calcium Sulfite

The influences on the performance of wet flue gas desulfurization system in mercury removing after adding mercury removal additive were studied. As a consequence, the mercury removal efficiency can be improved by this kind of additive, that the efficiency of elemental mercury and total mercury is raised along with the amount of additive is increased. And so can the desulfuration efficiency. The oxidation of calcium sulfite in desulfurization is promoted by the mercury removal additive, increase the reduce speed of calcium sulfite concentration.

Full Scale Evaluation and Suppression of Mercury Re-Emission in Wet Flue Gas Desulfurization System

2013 ◽  
Vol 316-317 ◽  
pp. 354-357 ◽  
Author(s):  
Cheng Li Wu ◽  
Yan Cao ◽  
Han Xu Li ◽  
Wei Ping Pan
Keyword(s):  
Flue Gas ◽  
Environmental Protection Agency ◽  
Catalytic Reduction ◽  
Field Testing ◽  
The United States ◽  
Full Scale ◽  
Flue Gas Desulfurization ◽  
Emission Rates ◽  
Forced Oxidation ◽  
Ontario Hydro

The full-scale of PC/Cyclone Boilers with common wet flue gas desulfurization (WFGD) with limestone forced oxidation (LSFO) was studied. Ontario Hydro Method (OHM) recommended by the United States Environmental Protection Agency (USEPA) was used to determine mercury emission and speciation at these two full-scale WFGD systems, and OHM quality assurance/quality control (QA/QC) was followed during the field testing. WFGD re-emission problems were repeatedly observed at this unit. Selective catalytic reduction (SCR) had significant effects on mercury removal and Hg0 re-emission rates across WFGD. Effects of injection of continuous chemicals additive containing HS-, S2- or I- on mercury re-emission control were also conducted at this unit.

Control of Hg0 Re-Emission from Simulated Wet Flue Gas Desulfurization Liquors by Sodium Dithiocarbamate

2012 ◽  
Vol 610-613 ◽  
pp. 1473-1477 ◽  
Author(s):  
Chuan Min Chen ◽  
Li Xing Jiang ◽  
Song Tao Liu ◽  
Yu Ze Jiang
Keyword(s):  
Oxygen Concentration ◽  
Removal Efficiency ◽  
Flue Gas ◽  
Industrial Application ◽  
Inhibition Efficiency ◽  
Operating Conditions ◽  
Flue Gas Desulfurization ◽  
Mercury Removal ◽  
Ph Values ◽  
Oxygen Concentrations

Secondary atmospheric pollutions may result from wet flue gas desulfurization (WFGD) systems caused by the reduction of Hg2+to Hg0and lead to a damping of the co-benefit mercury removal efficiency by WFGD systems. The effects of the operating conditions, which included the pH, temperature, and oxygen concentrations, on Hg0re-emission inhibition efficiency by DTCR from WFGD liquors was carried out. The established data reflected an outstanding performance on the Hg0re-emission inhibition from the simulated WFGD liquors by adding DTCR. Our data suggested that a concentration of 0.0005% (v/v) was enough for Hg0re-emission inhibition in the simulated WFGD liquors. The results also indicated that the Hg0re-emission inhibition efficiency by adding DTCR decreased as the operational temperatures increased and the Hg0re-emission inhibition efficiency increased as pH values and the oxygen concentration in the flue gas increased. The present findings could be valuable for industrial application of DTCR as a precipitant for stabilizing dissolved Hg2+to prevent re-emission of Hg0in WFGD solutions.

scholarly journals Ion Selective Electrodes for Flue Gas Desulfurization Wastewater Monitoring: Effects of Ionic Strength on Selective Ions

2019 ◽  
Vol 9 (15) ◽  
pp. 3085
Author(s):  
Kyle McGaughy ◽  
Jay P. Wilhelm ◽  
M. Toufiq Reza
Keyword(s):  
Ionic Strength ◽  
Flue Gas ◽  
Sampling Rate ◽  
Operating Conditions ◽  
Flue Gas Desulfurization ◽  
Ion Selective Electrodes ◽  
Wastewater Sample ◽  
Electrode Performance ◽  
Relative Errors ◽  
Nitrate And Nitrite

Ion selective electrodes (ISE) were evaluated for use in a flue gas desulfurization (FGD) wastewater monitoring system. Calcium, chloride, nitrate, and nitrite ISE’s were calibrated in a broad range of concentrations that were designed to model an actual FGD wastewater sample that was obtained from an industrial partner. Ideal Nernst, Modified Nernst, and a multiparameter regression analysis was performed for each electrode and evaluated on general fit and sensitivity at anticipated operating conditions. The Ideal Nernst equation, even with correction for ionic strength, was not able to properly model actual electrode performance. The multiparameter regression was able to model the electrode performance with relative errors of 10–25% when ionic strengths were below 0.1 M. Through the evaluation of real-time sensor usage at real conditions, a methodology of washing and sampling rate is suggested to minimize error in the readings.

scholarly journals Advanced and Intensified Seawater Flue Gas Desulfurization Processes: Recent Developments and Improvements

Energies ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5917 ◽  
Author(s):  
Nguyen Van Duc Long ◽  
Dong Young Lee ◽  
Kim Myung Jin ◽  
Kwag Choongyong ◽  
Lee Young Mok ◽  
...  
Keyword(s):  
Flue Gas ◽  
Gas Flow ◽  
Process Integration ◽  
Waste Heat ◽  
Combined Treatment ◽  
Industrial Applications ◽  
Operating Conditions ◽  
Flue Gas Desulfurization ◽  
Loading Capacity ◽  
Equipment Size

Seawater flue gas desulfurization (SWFGD) is considered to be a viable solution for coastal and naval applications; however, this process has several drawbacks, including its corrosive absorbent; low vapor loading capacity since the solubility of sulfur oxides (SOx) in seawater is lower than that of limestone used in conventional methods; high seawater flowrate; and large equipment size. This has prompted process industries to search for possible advanced and intensified configurations to enhance the performance of SWFGD processes to attain a higher vapor loading capacity, lower seawater flowrate, and smaller equipment size. This paper presents an overview of new developments as well as advanced and intensified configurations of SWFGD processes via process modifications such as modification and optimization of operating conditions, improvement of spray and vapor distributors, adding internal columns, using square or rectangular shape, using a pre-scrubber, multiple scrubber feed; process integration such as combined treatment of SOx and other gases, and waste heat recovery; and process intensification such as the use of electrified sprays, swirling gas flow, and rotating packed beds. A summary of the industrial applications, engineering issues, environmental impacts, challenges, and perspectives on the research and development of advanced and intensified SWFGD processes is presented.

Effects of pH on Hg0 Re-Emission in WFGD

2014 ◽  
Vol 960-961 ◽  
pp. 462-468 ◽  
Author(s):  
Yong Qiu ◽  
Hui Wu ◽  
Guang Qian Luo ◽  
Hong Yao
Keyword(s):  
Flue Gas ◽  
Laboratory Experiments ◽  
Low Ph ◽  
Time Span ◽  
Flue Gas Desulfurization ◽  
Solution Theory ◽  
High Ph ◽  
Ph Values ◽  
Effects Of Ph ◽  
Conventional Solution

Gaseous oxidized mercury (Hg2+) in the flue gas is soluble in water and can be captured effectively by Wet flue gas desulfurization (WFGD) system. But in some extent Hg0re-emission happens due to the reduction of absorbed Hg2+, and the pH of slurry is an important factor affecting Hg0re-emission. In this study, the theoretical formulas of slurry pH were derived through the conventional solution theory and then were used to evaluate the factors determining the pH of slurry. A series of laboratory experiments were carried out under N2,CO2and O2/N2atmosphere to measure the Hg0re-emission tendency at different pH values. The results show that the higher the pH, the less Hg2+reduced by S(IV), resulting in the decrease of Hg0re-emission. Under N2atmosphere, the Hg0re-emission was mild at pH>4 while it was dramatic at pH<4. Under O2/N2atmosphere, the addition of O2extended the time span of Hg0re-emission at low pH and increased Hg0re-emission unexpectedly in the latter part of the experiments at high pH. CO2atmosphere almost did not affect Hg0re-emission because of its little effect on the slurry pH.

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