Pilot-scale demonstration of the hybrid zero-valent iron process for treating flue-gas-desulfurization wastewater: Part I

The hybrid zero-valent-iron (hZVI) process is a novel chemical treatment process that has shown great potential in previous laboratory and field bench-top scale tests for removing selenium, mercury and nutrients from various industrial wastewaters. In this study, a pilot-scale demonstration was conducted to continuously treat 3.8–7.6 L/min (1–2 gpm) of the flue-gas-desulfurization (FGD) wastewater at a coal-fired power plant for five months. Results show that the hZVI process could simultaneously reduce selenate-Se from 1 to 3 mg/L to below 10 μg/L and mercury from over 100 μg/L to below 10 ng/L in compliance with the new stringent effluent discharge limits planned by the U.S. EPA for Se and Hg. A three-stage hZVI system with a combined hydraulic retention time of 12 h is sufficient for Se treatment, while a single-stage system can meet Hg treatment requirement. The successful pilot study demonstrated that the hZVI process is scalable and could be a reliable, low-cost, high-performance treatment platform with many application potentials, particularly, for solving some of the toughest heavy metal water problems.

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Pilot-scale demonstration of the hybrid zero-valent iron process for treating flue-gas-desulfurization wastewater: Part II

Water Science & Technology ◽

10.2166/wst.2012.447 ◽

2013 ◽

Vol 67 (2) ◽

pp. 239-246 ◽

Cited By ~ 14

Author(s):

Yong H. Huang ◽

Phani K. Peddi ◽

Hui Zeng ◽

Ci-Lai Tang ◽

Xinjun Teng

Keyword(s):

Heavy Metals ◽

Flue Gas ◽

High Performance ◽

Treatment Process ◽

Low Cost ◽

Pilot Scale ◽

Zero Valent Iron ◽

Flue Gas Desulfurization ◽

Waste Production ◽

Water Problems

The hybrid zero-valent-iron (hZVI) process is a novel chemical treatment process that has shown promise for removing heavy metals and nutrients from industrial wastewaters. In this study, a pilot-scale demonstration was conducted to continuously treat 3.8–7.6 L/min (1–2 gpm) of the flue-gas-desulfurization (FGD) wastewater at a coal-fired power plant for 5 months. In this paper, a spike test was conducted to evaluate performance of the hZVI process for removing selected toxic metals at artificially elevated concentrations. The results showed that a multiple-stage hZVI process could decrease selenate-Se from 22 mg/L to ∼10 μg/L and dissolved Hg2+ from 1.15 mg/L to ∼10 ng/L. In addition, the process simultaneously removed a broad spectrum of heavy metals such as As(III), As(V), Cr(VI), Cd(II), Pb(II) and Cu(II) from mg/L to near or sub-ppb (μg/L) level after a single-stage treatment. The process consumed about 0.3 kg ZVI per 1 m3 FGD wastewater treated at a cost of about US$0.6/m3. Solid waste production and energy consumption were reasonably low. The successful pilot study demonstrated that the hZVI technology can be a low-cost, high-performance treatment platform for solving some of the toughest heavy metal water problems.

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Kinetic model for calcium sulfate α-hemihydrate produced hydrothermally from gypsum formed by flue gas desulfurization

Journal of Applied Crystallography ◽

10.1107/s1600576715007141 ◽

2015 ◽

Vol 48 (3) ◽

pp. 827-835 ◽

Cited By ~ 10

Author(s):

Mingliang Tang ◽

Xuerun Li ◽

Yusheng Shen ◽

Xiaodong Shen

Keyword(s):

Flue Gas ◽

Calcium Sulfate ◽

High Performance ◽

Transformation Process ◽

Flue Gas Desulfurization ◽

Synthesis Process ◽

Stable Phase ◽

Hydrothermal Conditions ◽

Simple Method ◽

Kinetics Of

Modeling of the kinetics of the synthesis process for calcium sulfate α-hemihydrate from gypsum formed by flue gas desulfurization (FGD) is important to produce high-performance products with minimal costs and production cycles under hydrothermal conditions. In this study, a model was established by horizontally translating the obtained crystal size distribution (CSD) to the CSD of the stable phase during the transformation process. A simple method was used to obtain the nucleation and growth rates. A nonlinear optimization algorithm method was employed to determine the kinetic parameters. The model can be successfully used to analyze the transformation kinetics of FGD gypsum to α-hemihydrate in an isothermal batch crystallizer. The results showed that the transformation temperature and stirring speed exhibit a significant influence on the crystal growth and nucleation rates of α-hemihydrate, thus altering the transformation time and CSD of the final products. The characteristics obtained by the proposed model can potentially be used in the production of α-hemihydrate.

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Study on Flue Gas Desulfurization of Sintering in Pilot-Scale Experiment

2011 International Conference on Computer Distributed Control and Intelligent Environmental Monitoring ◽

10.1109/cdciem.2011.302 ◽

2011 ◽

Author(s):

Wu Fuzhong ◽

Wang Wenhao

Keyword(s):

Flue Gas ◽

Pilot Scale ◽

Flue Gas Desulfurization ◽

Scale Experiment

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Advanced Coal-Fired Power Plants

Journal of Energy Resources Technology ◽

10.1115/1.1348270 ◽

2000 ◽

Vol 123 (1) ◽

pp. 4-9 ◽

Cited By ~ 7

Author(s):

Lawrence A. Ruth

Keyword(s):

Power Systems ◽

Flue Gas ◽

High Performance ◽

Power Plants ◽

Pilot Scale ◽

Combined Cycle ◽

Department Of Energy ◽

Electric Power Plants ◽

Air Temperatures ◽

Low Emission

The U.S. Department of Energy is partnering with industry to develop advanced coal-fired electric power plants that are substantially cleaner, more efficient, and less costly than current plants. Low-emission boiler systems (LEBS) and high-performance power systems (HIPPS) are based, respectively, on the direct firing of pulverized coal and the indirectly fired combined cycle. LEBS uses a low-NOx slagging combustion system that has been shown in pilot-scale tests to emit less than 86 g/GJ (0.2 lb/106 Btu) of NOx. Additional NOx removal is provided by a moving bed copper oxide flue gas cleanup system, which also removes 97–99 percent of sulfur oxides. Stack levels of NOx can be reduced to below 9 g/GJ (0.02 lb/106 Btu). Construction of an 80 MWe LEBS proof-of-concept plant is scheduled to begin in the spring of 1999. Engineering development of two different HIPPS configurations is continuing. Recent tests of a radiant air heater, a key component of HIPPS, have indicated the soundness of the design for air temperatures to 1150°C. LEBS and HIPPS applications include both new power plants and repowering/upgrading existing plants.

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