Mercury(II) reduction and sulfite oxidation in aqueous systems: kinetics study and speciation modeling

2017 ◽  
Vol 14 (3) ◽  
pp. 151 ◽  
Author(s):  
Kurt L. B. Solis ◽  
Go-un Nam ◽  
Yongseok Hong
Keyword(s):  
Flue Gas ◽  
Power Plants ◽  
Vapour Phase ◽  
Model Fit ◽  
Mercury Ions ◽  
Model Following ◽  
Sulfite Oxidation ◽  
Pseudo Second Order ◽  
Unstable Complex ◽  
Water Acidity

Environmental contextWastewater contains various substances such as sulfur-containing chemicals and heavy metals including mercury ions. Several technologies have been developed to trap mercury ions; however, mercury can undergo reactions with sulfite and change to its vapour form, which easily escapes to the atmosphere. Here, we devised a model to predict the formation of vapour-phase mercury as a function of sulfite concentration, temperature and water acidity based on coal-fired power plant wastewater. AbstractThe re-emission of mercury (Hg) as a consequence of the formation and dissociation of the unstable complex HgSO3 is a problem encountered in flue gas desulfurisation treatment in coal-fired power plants. A model following a pseudo-second-order rate law for Hg2+ reduction was derived as a function of [SO32–], [H+] and temperature and fitted to experimentally obtained data to generate kinetics rate values of 0.120±0.04, 0.847±0.07, 1.35±0.4mM–1 for 40°C, 60°C and 75°C respectively. The rate of reduction of Hg2+ increases with a temperature increase but shows an inverse relationship with proton concentration. Plotting the model-fit kinetics rate constants yields ΔH=61.7±1.82 kJ mol–1, which is in good agreement with literature values for the formation of Hg0 by SO32–. The model could be used to better understand the overall Hg2+ re-emission due to SO32– happening in aquatic systems such as flue gas desulfurisation wastewaters.

Experimental investigation of sulfite oxidation enhancement in a micro-pore aeration system

RSC Advances ◽  
2016 ◽  
Vol 6 (106) ◽  
pp. 104139-104147 ◽  
Author(s):  
Jun Zhang ◽  
Cheng-hang Zheng ◽  
Yong-xin Zhang ◽  
Zhe-wei Xu ◽  
Li Wang ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Flue Gas ◽  
Power Plants ◽  
Flue Gas Desulfurization ◽  
Sulfite Oxidation ◽  
Aeration System ◽  
System P

Seawater wet flue gas desulfurization is a promising process for coal-fired power plants.

Application and Research of High Molecular Carboxylates in Desulphurization System of Thermal Power Plant

2018 ◽  
Vol 917 ◽  
pp. 175-179
Author(s):  
Yan Chang Kang ◽  
Bing Li ◽  
Qi Long Zhang
Keyword(s):  
Flue Gas ◽  
Calcium Sulfate ◽  
Power Plants ◽  
Thermal Power ◽  
Test Method ◽  
Flue Gas Desulfurization ◽  
Carboxyl Groups ◽  
Chemical Absorption ◽  
Sulfite Oxidation ◽  
Main Components

The main components of polymer carboxyl group are introduced.The effects of macromolecular carboxyl groups on the limestone-gypsum wet flue gas desulfurization (FGD) system of coal-fired power plants in China were studied by test method. The results showed that the macromolecular carboxyl groups can accelerate the chemical absorption of SO2 under the action of active agents and crystallization agents, improve the desulfurization efficiency of about 2%, and shorten the limestone ablation time of more than 40%, catalytic calcium sulfite oxidation of calcium sulfate.

Could biomass-fueled boilers be operated at higher steam temperatures? Part 3: Initial analysis of costs and benefits

TAPPI Journal ◽  
2014 ◽  
Vol 13 (8) ◽  
pp. 65-78 ◽  
Author(s):  
W.B.A. (SANDY) SHARP ◽  
W.J. JIM FREDERICK ◽  
JAMES R. KEISER ◽  
DOUGLAS L. SINGBEIL
Keyword(s):  
Flue Gas ◽  
Power Plants ◽  
Superheated Steam ◽  
Black Liquor ◽  
Simulation Software ◽  
Operating Conditions ◽  
Costs And Benefits ◽  
Steam Generation ◽  
Fireside Corrosion ◽  
Corrosion Resistant

The efficiencies of biomass-fueled power plants are much lower than those of coal-fueled plants because they restrict their exit steam temperatures to inhibit fireside corrosion of superheater tubes. However, restricting the temperature of a given mass of steam produced by a biomass boiler decreases the amount of power that can be generated from this steam in the turbine generator. This paper examines the relationship between the temperature of superheated steam produced by a boiler and the quantity of power that it can generate. The thermodynamic basis for this relationship is presented, and the value of the additional power that could be generated by operating with higher superheated steam temperatures is estimated. Calculations are presented for five plants that produce both steam and power. Two are powered by black liquor recovery boilers and three by wood-fired boilers. Steam generation parameters for these plants were supplied by industrial partners. Calculations using thermodynamics-based plant simulation software show that the value of the increased power that could be generated in these units by increasing superheated steam temperatures 100°C above current operating conditions ranges between US$2,410,000 and US$11,180,000 per year. The costs and benefits of achieving higher superheated steam conditions in an individual boiler depend on local plant conditions and the price of power. However, the magnitude of the increased power that can be generated by increasing superheated steam temperatures is so great that it appears to justify the cost of corrosion-mitigation methods such as installing corrosion-resistant materials costing far more than current superheater alloys; redesigning biomassfueled boilers to remove the superheater from the flue gas path; or adding chemicals to remove corrosive constituents from the flue gas. The most economic pathways to higher steam temperatures will very likely involve combinations of these methods. Particularly attractive approaches include installing more corrosion-resistant alloys in the hottest superheater locations, and relocating the superheater from the flue gas path to an externally-fired location or to the loop seal of a circulating fluidized bed boiler.

Capturing CO2 in flue gas from fossil fuel-fired power plants using dry regenerable alkali metal-based sorbent

2013 ◽  
Vol 39 (6) ◽  
pp. 515-534 ◽  
Author(s):  
Chuanwen Zhao ◽  
Xiaoping Chen ◽  
Edward J. Anthony ◽  
Xi Jiang ◽  
Lunbo Duan ◽  
...  
Keyword(s):  
Alkali Metal ◽  
Flue Gas ◽  
Power Plants ◽  
Fossil Fuel

scholarly journals Effect of Flue Gases’ Corrosive Components on the Degradation Process of Evaporator Tubes

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3860
Author(s):  
Mária Hagarová ◽  
Milan Vaško ◽  
Miroslav Pástor ◽  
Gabriela Baranová ◽  
Miloš Matvija
Keyword(s):  
Flue Gas ◽  
Power Plants ◽  
Gas Flow ◽  
Degradation Process ◽  
Flue Gases ◽  
Saturated Steam ◽  
Mineral Salts ◽  
Related Factors ◽  
Local Overheating ◽  
Inner Surface

Corrosion of boiler tubes remains an operational and economic limitation in municipal waste power plants. The understanding of the nature, mechanism, and related factors can help reduce the degradation process caused by corrosion. The chlorine content in the fuel has a significant effect on the production of gaseous components (e.g., HCl) and condensed phases on the chloride base. This study aimed to analyze the effects of flue gases on the outer surface and saturated steam on the inner surface of the evaporator tube. The influence of gaseous chlorides and sulfates or their deposits on the course and intensity of corrosion was observed. The salt melts reacted with the steel surface facing the flue gas flow and increased the thickness of the oxide layer up to a maximum of 30 mm. On the surface not facing the flue gas flow, they disrupted the corrosive layer, reduced its adhesion, and exposed the metal surface. Beneath the massive deposits, a local overheating of the inner surface of the evaporator tubes occurred, which resulted in the release of the protective magnetite layer from the surface. Ash deposits reduce the boiler’s thermal efficiency because they act as a thermal resistor for heat transfer between the flue gases and the working medium in the pipes. The effect of insufficient feedwater treatment was evinced in the presence of mineral salts in the corrosion layer on the inner surface of the tube.

Novel Postcombustion Capture Process for CO2 from the Flue Gas of Coal-Fired Power Plants Using a Green Deep Eutectic Solvent

2020 ◽  
Vol 8 (5) ◽  
pp. 2236-2245
Author(s):  
Yinglong Wang ◽  
Yigang Liu ◽  
Xiaobin Liu ◽  
Guoxuan Li ◽  
Jianguang Qi ◽  
...  
Keyword(s):  
Flue Gas ◽  
Power Plants ◽  
Deep Eutectic Solvent ◽  
Capture Process

A novel lignite pre-drying system integrated with flue gas waste heat recovery at lignite-fired power plants

2019 ◽  
Vol 150 ◽  
pp. 200-209 ◽  
Author(s):  
Min Yan ◽  
Chunyuan Ma ◽  
Qiuwan Shen ◽  
Zhanlong Song ◽  
Jingcai Chang
Keyword(s):  
Flue Gas ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Power Plants ◽  
Waste Heat ◽  
Drying System

scholarly journals Solvent-Free Synthesis of Phosphonic Graphene Derivative and Its Application in Mercury Ions Adsorption

Nanomaterials ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 485
Author(s):  
Robert Olszewski ◽  
Małgorzata Nadolska ◽  
Marcin Łapiński ◽  
Marta Prześniak-Welenc ◽  
Bartłomiej Cieślik ◽  
...  
Keyword(s):  
Adsorption Efficiency ◽  
Mercury Ions ◽  
High Adsorption ◽  
Adsorption Selectivity ◽  
Nickel Ions ◽  
Cadmium Ions ◽  
First Order ◽  
Bivalent Ions ◽  
Pseudo Second Order ◽  
Solvent Free Synthesis

Functionalized graphene was efficiently prepared through ball-milling of graphite in the presence of dry ice. In this way, oxygen functional groups were introduced into material. The material was further chemically functionalized to produce graphene derivative with phosphonic groups. The obtained materials were characterized by spectroscopic and microscopic methods, along with thermogravimetric analysis. The newly developed material was used as an efficient mercury adsorbent, showing high adsorption efficiency. The adsorption isotherms were fitted using Freundlich and Langmuir models. The adsorption kinetics were fitted with pseudo-first order and pseudo-second order models. Adsorption selectivity was determined in the presence of cadmium ions and nickel ions. The presence of mentioned bivalent ions in the solution did not affect mercury adsorption efficiency.

Sign in / Sign up

Export Citation Format

Share Document