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.

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.

Flue Gas Desulfurization Wastewater Treatment for Coal-Fired Power Industry

2014 ◽  
Author(s):  
Behrang Pakzadeh ◽  
Jay Wos ◽  
Jay Renew
Keyword(s):  
Power Plant ◽  
Flue Gas ◽  
Environmental Protection Agency ◽  
Water Conservation ◽  
Power Plants ◽  
The United States ◽  
Power Industry ◽  
Flue Gas Desulfurization ◽  
Liquid Discharge ◽  
Plant Operations

The United States Environmental Protection Agency (USEPA)’s announcement that it will revise the effluent limitation guidelines for steam electric power generating units could affect not only how power plants use water, but also how they discharge it. The revised guidelines may lower discharge limits for various contaminants in flue gas desulfurization (FGD) wastewater including mercury, selenium, arsenic, and nitrate/nitrite. Although the specific details of the guidelines are unknown at present, the power industry is evaluating various technologies that may address the new effluent limitation guidelines and promote water conservation. Moreover, the power industry is looking for avenues to increase water usage efficiency, reuse and recycle throughout its plant processes. Final rule approval is expected by the middle of 2014 and new regulations are expected to be implemented between 2017 and 2022 through 5-year NPDES permit cycles. discharge limits for various contaminants including arsenic, mercury, selenium, and nitrate/nitrite [1]. These pollutant limits may be below the levels achievable today with conventional treatment [2]. A growing interest exists in zero liquid discharge (ZLD) facilities and processes in power plant operations. Potentially stringent discharge limits along with water conservation and reuse efforts are two of the major drivers to achieve ZLD. Potential pollutant levels are so low that ZLD may be the best option, if not an outright requirement [1]. Thermal ZLD systems have been the subject of increased interest and discussion lately. They employ evaporating processes such as ponds, evaporators and crystallizers, or spray dryers to produce a reusable water stream and a solid residue (i.e. waste). Evaporators and crystallizers have been employed in the power industry for a number of years. However, typical A growing interest exists in zero liquid discharge (ZLD) facilities and processes in power plant operations. Potentially stringent discharge limits along with water conservation and reuse efforts are two of the major drivers to achieve ZLD. Potential pollutant levels are so low that ZLD may be the best option, if not an outright requirement. A key disadvantage of thermal ZLD is its high capital cost. One way to reduce this cost is to pre-treat the liquid stream using innovative membrane technologies and reverse osmosis (RO).

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.

scholarly journals Investigation and Control Technology on Excessive Ammonia-Slipping in Coal-Fired Plants

Energies ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 4249
Author(s):  
Xuan Yao ◽  
Man Zhang ◽  
Hao Kong ◽  
Junfu Lyu ◽  
Hairui Yang
Keyword(s):  
Flue Gas ◽  
Power Plants ◽  
Catalytic Reduction ◽  
Flue Gas Desulfurization ◽  
Ammonia Emission ◽  
Dust Collector ◽  
Neural Network Algorithm ◽  
Injection Technology ◽  
And Control ◽  
The Relationship

After the implementation of the ultra-low emissions regulation on the coal-fired power plants in China, the problem of the excessive ammonia-slipping from selective catalytic reduction (SCR) seems to be more severe. This paper analyzes the operating statistics of the coal-fired plants including 300 MW/600 MW/1000-MW units. Statistics data show that the phenomenon of the excessive ammonia-slipping is widespread. The average excessive rate is over 110%, while in the small units the value is even higher. A field test data of nine power plants showed that excessive ammonia-slipping at the outlet of SCR decreased following the flue-gas process. After most ammonia reduced by the dust collector and the wet flue-gas desulfurization (FGD), the ammonia emission at the stack was extremely low. At same time, a method based on probability distribution is proposed in this paper to describe the relationship between the NH3/NOX distribution deviation and the De–NOX efficiency/ammonia-slipping. This paper also did some original work to solve the ammonia-slipping problem. A real-time self-feedback ammonia injection technology using neural network algorithm to predict and moderate the ammonia distribution is proposed to decrease the NH3/NOX deviation and excessive ammonia-slipping. The technology is demonstrated in a 600-MW unit and works successfully. The excessive ammonia-slipping problem is well controlled after the implementation of the technology.

scholarly journals Influence of ammonia on wet-limestone flue gas desulfurization process from coal-based power plant

2019 ◽  
Vol 116 ◽  
pp. 00101
Author(s):  
Tomasz Wypiór ◽  
Renata Krzyżyńska
Keyword(s):  
Particulate Matter ◽  
Flue Gas ◽  
Gas Flow ◽  
Catalytic Reduction ◽  
Flue Gases ◽  
Flue Gas Desulfurization ◽  
Flow Capacity ◽  
Desulfurization Process ◽  
Denitrification Process ◽  
Raw Wastewater

The paper presents data concerning the influence of ammonia on wet flue gas desulfurization (WFGD) absorber. Paper presents preliminary results of an industrial scale study on WFGD absorber, that collects flue gases from four boilers with total flue gas flow capacity of the WFGD equal to 1 500 000 Nm3/h. Each boiler is equipped with selective non-catalytic reduction (SNCR) with urea injection. It was shown, that ammonia present in the flue gas upstream the WFGD increases the pH of absorption slurry, impacting the desulphurization process. In addition, analysis of particulate matter upstream and downstream the absorber shows an increase of the concentration of ammonium species in the particulate matter about 14 times, as average. Moreover, a non-optimized denitrification process can cause a high NH4+ concentration in the absorption slurry (up to 768 mg/L) and raw wastewater (up to 891 mg/L).

scholarly journals Evaluation of GEOS-5 sulfur dioxide simulations during the Frostburg, MD 2010 field campaign

2014 ◽  
Vol 14 (4) ◽  
pp. 1929-1941 ◽  
Author(s):  
V. Buchard ◽  
A. M. da Silva ◽  
P. Colarco ◽  
N. Krotkov ◽  
R. R. Dickerson ◽  
...  
Keyword(s):  
Air Quality ◽  
Sulfur Dioxide ◽  
Environmental Protection Agency ◽  
Global Climate ◽  
The United States ◽  
Global Scale ◽  
Emission Rates ◽  
Anthropogenic Emission ◽  
Atmospheric Pollutant ◽  
Field Campaign

Abstract. Sulfur dioxide (SO2) is a major atmospheric pollutant with a strong anthropogenic component mostly produced by the combustion of fossil fuel and other industrial activities. As a precursor of sulfate aerosols that affect climate, air quality, and human health, this gas needs to be monitored on a global scale. Global climate and chemistry models including aerosol processes along with their radiative effects are important tools for climate and air quality research. Validation of these models against in-situ and satellite measurements is essential to ascertain the credibility of these models and to guide model improvements. In this study, the Goddard Chemistry, Aerosol, Radiation, and Transport (GOCART) module running on-line inside the Goddard Earth Observing System version 5 (GEOS-5) model is used to simulate aerosol and SO2 concentrations. Data taken in November 2010 over Frostburg, Maryland during an SO2 field campaign involving ground instrumentation and aircraft are used to evaluate GEOS-5 simulated SO2 concentrations. Preliminary data analysis indicated the model overestimated surface SO2 concentration, which motivated the examination of the specification of SO2 anthropogenic emission rates. As a result of this analysis, a revision of anthropogenic emission inventories in GEOS-5 was implemented, and the vertical placement of SO2 sources was updated. Results show that these revisions improve the model agreement with observations locally and in regions outside the area of this field campaign. In particular, we use the ground-based measurements collected by the United States Environmental Protection Agency (US EPA) for the year 2010 to evaluate the revised model simulations over North America.

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