scholarly journals Effect of additives on mercury partitioning in wet-limestone flue-gas desulfurization

Clean Energy ◽  
2020 ◽  
Vol 4 (2) ◽  
pp. 132-141 ◽  
Author(s):  
Ida Masoomi ◽  
Barna Heidel ◽  
Marc Oliver Schmid ◽  
Günter Scheffknecht
Keyword(s):  
Redox Potential ◽  
Aqueous Phase ◽  
Solid Fraction ◽  
Flue Gas ◽  
Water Soluble ◽  
Flue Gas Desulfurization ◽  
Mercury Compounds ◽  
So2 Removal ◽  
Reducing Environment ◽  
So2 Absorption

Abstract The wet-flue-gas desulfurization (FGD) process plays an important role in removing water-soluble flue-gas components such as sulphur dioxide (SO2) and oxidized mercury compounds. Under the reducing environment of the FGD, there is the possibility of re-emission of the already absorbed mercury (Hg) to the gas phase, which may be diminished by the utilization of specific additives. In this study, the effect of two different additives on Hg re-emission from the aqueous phase and Hg partitioning in gypsum and filtrate of a lab-scale wet-limestone FGD is investigated. Furthermore, the behaviour of additives in the presence of different halides is studied. The studied additives are TMT 15® as a sulphidic precipitating agent, which forms non-soluble mercury compounds, and activated lignite (AL) as a carbon-based sorbent, which adsorbs Hg compounds from the aqueous phase. TMT 15® has no significant effect on SO2 absorption; on the other hand, addition of AL improves the SO2-removal efficiency by up to 30%. Using both additives, Hg re-emission is suppressed in all the experimented cases except for AL in the absence of halides, in which Hg re-emission shows no change. Thus, the need to form nucleophilic oxidized mercury compounds in the slurry for the adsorption of oxidized mercury on AL can be concluded. Usage of both additives improves Hg retention in the slurry to different extents. It is shown that, for the additive-free slurries, the Hg-adsorption capacity of the solid fraction of the slurry is the limiting parameter. Moreover, the utilization of both additives results in a significant increase in the Hg concentration of solid fraction. The correlation between redox potential and partitioning of Hg in the slurry is presented by comparing the change in the redox potential of slurries when additives are used.

Modelling Flue Gas Desulfurization Using Pyrolusite Pulp in a Jet Bubbling Reactor

2009 ◽  
Vol 610-613 ◽  
pp. 85-96 ◽  
Author(s):  
Jing Dong Zhao ◽  
Shi Jun Su ◽  
Nan Shan Ai ◽  
Xiao Fan Zhu
Keyword(s):  
Flue Gas ◽  
Ph Value ◽  
Scale Up ◽  
Absorption Efficiency ◽  
Flue Gas Desulfurization ◽  
Process Conditions ◽  
Gas Temperature ◽  
Transfer Coefficients ◽  
Set Up ◽  
So2 Absorption

A mathematical model for flue gas desulfurization using pyrolusite pulp in jet bubbling reactor (JBR) was described. Firstly, based on the concept of two stages mass balance with chemical reaction, two models were set up, for jet bubbling zone and rising bubble zone, respectively, according to the construction of JBR. The models consist of two coupling differential equations and were solved simultaneously by integral and separation of the variables. Then the SO2 absorption efficiency expression was developed, considering the great discrepancy existing between the gas-side mass transfer coefficients of the jet bubbling zone and gas bubble rising zone. The final expression associates SO2 absorption efficiency with process conditions and JBR structure parameters, which can give some instruction and guidance for the study of reactor operation process. Predicted results from the theoretical model, including effect of pH value of the pulp, flue gas temperature and inlet SO2 concentration of flue gas on SO2 absorption efficiency, were found to be in good agreement with experimental data obtained in a jet bubbling reactor. The model provides a basis for the process scale up and operating guide.

The effect of hydrogen peroxide solution on SO2 removal in the semidry flue gas desulfurization process

2009 ◽  
Vol 170 (1) ◽  
pp. 436-442 ◽  
Author(s):  
Yuegui Zhou ◽  
Xian Zhu ◽  
Jun Peng ◽  
Yaobin Liu ◽  
Dingwang Zhang ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Flue Gas ◽  
Hydrogen Peroxide Solution ◽  
Flue Gas Desulfurization ◽  
So2 Removal ◽  
Desulfurization Process

New Wet Flue Gas Desulfurization Process Using Granular Limestone and Organic Acid Additives

2006 ◽  
Vol 4 (1) ◽  
Author(s):  
Shengyu Liu ◽  
Wende Xiao
Keyword(s):  
Acetic Acid ◽  
Sulfur Dioxide ◽  
Organic Acid ◽  
Removal Efficiency ◽  
Flue Gas ◽  
Flue Gas Desulfurization ◽  
So2 Removal ◽  
New Process ◽  
Desulfurization Process ◽  
Sulfur Dioxide Removal

A new wet FGD process in which sulfur dioxide was absorbed in the bubble reactor using granular limestone simultaneously adding acetic acid had been proposed. The main difference compared to conventional wet FGD process was the ability of the new process to utilize granular limestone directly as a desulphurization reagent simultaneously adding acetic acid. Thus, the pulverizing of limestone, which causes power consumption, can be saved. Only using granular limestone directly as absorbent without acetic acid, SO2 removal efficiency and limestone utilization were too low. Adding some concentration of acetic acid, the performance of the new wet FGD process was confirmed to be equal to or higher than that of a conventional process in various tests. Various parameters of the new FGD process which would affect the sulfur dioxide removal efficiency and limestone utilization were studied.

Modeling and Simulation of Sulfur Dioxide Abatement with Ammonia Absorbent in the Spray Scrubber

2012 ◽  
Vol 599 ◽  
pp. 404-411 ◽  
Author(s):  
Yong Jia
Keyword(s):  
Flue Gas ◽  
Operating Conditions ◽  
Flue Gas Desulfurization ◽  
Gas Velocity ◽  
Desulfurization Process ◽  
Spray Scrubber ◽  
Influence Of Ph ◽  
So2 Absorption ◽  
Gas Ratio ◽  
So2 Concentration

In this paper, a model of ammonia-based wet flue gas desulfurization system was developed to simulate the process of absorption of SO2 and oxidation of total sulfite. The influence of pH, liquid-gas ratio, flue gas velocity and SO2 concentration on the desulfurization process were analyzed. The calculated desulfurization efficiency of the ammonia-based WFGD system for 2×210 t•h-1 boilers unit in China were compared to that of corresponding measured ones. The results show that the simulated values agreed well with the measured values for the operating conditions of pH, liquid/gas ratio and SO2 concentration. Corresponding amount of air needed for oxidation of total sulfite formed in SO2 absorption process was also calculated.

Numerical Model of FGD Unit in Power Plant

2014 ◽  
Author(s):  
Armin Silaen ◽  
Bin Wu ◽  
Chenn Q. Zhou ◽  
William Breen
Keyword(s):  
Numerical Model ◽  
Flue Gas ◽  
Flue Gas Desulfurization ◽  
Discrete Phase Model ◽  
Tank Model ◽  
Discrete Phase ◽  
Parametric Studies ◽  
Tower Model ◽  
Model Technique ◽  
So2 Absorption

Numerical model technique was employed to model the reactive multiphase flow inside a flue gas desulfurization (FGD) unit. The model was divided into two parts: (a) the absorption tower model and (b) the reaction tank model. Eulerian-Lagrangian approach was employed in the absorption tower model. Discrete phase model was used to model the limestone slurry droplets and the SO2 absorption by the limestone slurry was included in the model. Eulerian-Eulerian approach was employed in the reaction tank model where the oxidation of the slurry to form gypsum was modeled. The absorption tower model and the reaction tank model are coupled. Parametric studies were performed to investigate the SO2 removal efficiency of the unit.

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