scholarly journals Methods to Reduce Mercury and Nitrogen Oxides Emissions from Coal Combustion Processes

2021 ◽  
Author(s):  
Maria Jędrusik ◽  
Dariusz Łuszkiewicz ◽  
Arkadiusz Świerczok
Keyword(s):  
Nitrogen Oxides ◽  
Flue Gas ◽  
Field Tests ◽  
Flue Gases ◽  
Hard Coal ◽  
Sodium Chlorite ◽  
Mercury Emissions ◽  
Pros And Cons ◽  
Injection Technology ◽  
Combustion Processes

The chapter presents the issue of reducing mercury and nitrogen oxides emissions from the flue gas of coal-fired boilers. The issue is particularly relevant due to the stricter regulations regarding exhaust gas purity. A brief review of the methods for reducing Hg and NOx emissions has been made, pointing out their pros and cons. Against this background, the results of the authors’ own research on the injection of selected oxidants into flue gases to remove both of these pollutants are presented. The injection of sodium chlorite solution into the flue gas (400 MWe lignite fired unit) upstream the wet flue gas desulphurization (WFGD) absorber contributed to the oxidation of both metallic mercury and nitric oxide and enhanced their removal efficiency. The results of tests on lignite and hard coal flue gases indicate that in order to reduce the unfavorable phenomenon of mercury re-emission from WFGD absorbers, in some cases, it is necessary to add selected chemical compounds (e.g., sulfides) to the desulfurization system. The results of field tests for flue gas from lignite (400 MWe unit) and hard coal-fired boilers (195 and 220 MWe units) confirmed the usefulness of oxidizer injection technology to reduce mercury emissions below the level required by BAT conclusions.

scholarly journals Technology of mercury removal from exhaust from coal fired boilers

2021 ◽  
Vol 323 ◽  
pp. 00024
Author(s):  
Dariusz Łuszkiewicz ◽  
Maria Jędrusik ◽  
Arkadiusz Świerczok
Keyword(s):  
Flue Gas ◽  
Power Plants ◽  
Field Tests ◽  
Hard Coal ◽  
The European Union ◽  
Metallic Mercury ◽  
Mercury Emissions ◽  
Gas Cleaning ◽  
Current Emission ◽  
Bat Conclusions

For the Polish power industry, the basic fuel is hard coal and lignite, which contains significant amounts of mercury. Current emission standards in the European Union (IED directive and in the near future BAT conclusions) create conditions for investment in flue gas cleaning installations for coal-fired power plants. During the combustion of coal, mainly metallic mercury (Hg0) is produced, which is difficult to remove from the flue gas in dedusting installations (electrostatic precipitators and fabric filters) and wet flue gas desulphurization plants. In these installations, oxidized mercury (Hg2+) and ash bound mercury (Hg(p)) are removed. In order to reduce the mercury concentration in flue gases, the DEMERTEC technology was created, which is based on the oxidation of metallic mercury to an oxidized form and its removal from flue gas in an existing flue gas de-dusting or de-sulphurization installations. The article presents the results of field tests of the DEMERTEC technology for flue gas from hard coal and lignite. This technology was tested on a ~ 400 MWe unit fed with lignite and on an FGD absorber in which flue gas was purified from two units with a capacity of 195 and 220 MWe fed with hard coal. In both cases, mercury emissions were reduced below the levels required by the BAT conclusions.

scholarly journals RESEARCH OF INFLUENCE OF AIR TEMPERATURE ON THE LEVEL OF NITROGEN OXIDES IN SMOKE GASES OF BOILER PLANTS

2019 ◽  
Vol 9 (4) ◽  
pp. 27-32
Author(s):  
Olga A. BALANDINA ◽  
Svetlana M. PURING
Keyword(s):  
Mathematical Modeling ◽  
Nitric Oxide ◽  
Nitrogen Oxides ◽  
Flue Gas ◽  
Software Package ◽  
Flame Temperature ◽  
Combustion Process ◽  
Flue Gases ◽  
Oxidizing Agent ◽  
Mixture Formation

The analysis of the values of the concentrations of the formed nitrogen oxides and the temperatures of the jet plume under various conditions of mixture formation is carried out. The plots of the distribution of torch temperatures and concentrations of nitric oxide in the calculated area for oxidizer temperatures of 20, 60, 100, 150, and 200 ° C were obtained and analyzed. Mathematical modeling of the gaseous fuel combustion process was carried out using the FlowVision software package. An analysis of the results showed that a decrease in the temperature of the air supplied as an oxidizing agent leads to a significant decrease in the concentration of nitrogen oxides in flue gases, while not significantly affecting the change in the flame temperature. The research results can be used to solve the problems of optimizing boiler plants, in order to reduce harmful flue gas emissions. Further modeling is planned to determine the dependence of the influence of various factors on the degree of formation of nitrogen oxides in the flue gases of boiler plants.

scholarly journals Lab-scale evaluation of possible mercury speciation in flue gas and mercury emission from combustion of pulverised solid fuels

2019 ◽  
Vol 201 ◽  
pp. 06001
Author(s):  
Maciej Cholewiński ◽  
Wiesław Rybak
Keyword(s):  
Flue Gas ◽  
Combustion Process ◽  
Flue Gases ◽  
Solid Fuels ◽  
Hard Coal ◽  
Scale Evaluation ◽  
Gaseous Products ◽  
Scale Method ◽  
Early Validation ◽  
Solid Biomass

In this work a new lab-scale method dedicated to the evaluation of both concentration and oxidation level of mercury in flue gases from pulverised fuel fired boiler was proposed. To detect the abovementioned parameters, 2 main steps need to be evaluated. Firstly, a calorimeter bomb is utilised - by a proper implementation of mass balance of mercury within substrates and products, the quantity of oxidised mercury in gaseous products can be evaluated. Then, to simulate solid fuel fired power unit and to calculate mercury concentrations in flue gases, one of the stoichiometric mathematical models of combustion process must be applied. Early validation of the method showed considerable differences between solid fuels in mercury oxidation efficiencies and concentrations in flue gasses. Four examined fuels (lignite, hard coal and 2 types of solid biomass) was investigated. Calculated mercury concentrations in raw flue gas (>700°C) varied between 4 and 75 µg/m3ref. The lowest quantity of oxidised forms ofHg in flue gases were identified in the case of investigated lignite (27% of total Hg), while significantly higher – for selected hard coal (72%) and one type of biomass (with high chlorine concentration; up to 98%).

scholarly journals Dioxin emissions from coal combustion in domestic stove: Formation in the chimney and coal chlorine content influence

2015 ◽  
Vol 19 (1) ◽  
pp. 295-304 ◽  
Author(s):  
Bostjan Paradiz ◽  
Panagiota Dilara ◽  
Gunther Umlauf ◽  
Ivan Bajsic ◽  
Vincenc Butala
Keyword(s):  
Flue Gas ◽  
Coal Combustion ◽  
Pronounced Effect ◽  
Flue Gases ◽  
Chlorine Content ◽  
Hard Coal ◽  
Waste Incinerator ◽  
Gas Temperature ◽  
Order Of Magnitude ◽  
Domestic Stove

Combustion experiments conducted in domestic stove burning hard coal demonstrated a predominant influence of the coal chlorine content on the PCDD/F emissions, together with a pronounced effect of the flue gas temperature. PCDD/F concentrations of over 100 ng TEQ/m3, three orders of magnitude higher than in a modern waste incinerator, were measured in the flue gases of a domestic stove when combusting high chlorine coal (0.31 %). The PCDD/F concentrations in the flue gases dropped below 0,5 ng TEQ/m3, when low chlorine coal (0.07 %) was used. When low chlorine coal was impregnated with NaCl to obtain 0.38 % chlorine content, the emission of the PCDD/Fs increased by two orders of magnitude. Pronounced nonlinearity of the PCDD/F concentrations related to chlorine content in the coal was observed. The combustion of the high chlorine coal yielded PCDD/F concentrations in flue gases one order of magnitude lower in a fan cooled chimney when compared to an insulated one, thus indicating formation in the chimney. The influence of flue gas temperature on the PCDD/F emissions was less pronounced when burning low chlorine coal. The predominant pathway of the PCDD/F emissions is via flue gases, 99 % of the TEQ in the case of the high chlorine coal for insulated chimney.

Application of Disk Aerators to Recarbonation of Alkaline Wastewater from Wet Gasification of Carbide

1991 ◽  
Vol 24 (7) ◽  
pp. 277-284 ◽  
Author(s):  
E. Gomólka ◽  
B. Gomólka
Keyword(s):  
Carbon Dioxide ◽  
Liquid Phase ◽  
Gas Phase ◽  
Flue Gas ◽  
Carbonic Acid ◽  
Low Cost ◽  
Flue Gases ◽  
Carbon Dioxide Content ◽  
Patent Claim ◽  
Phase Dispersion

Whenever possible, neutralization of alkaline wastewater should involve low-cost acid. It is conventional to make use of carbonic acid produced via the reaction of carbon dioxide (contained in flue gases) with water according to the following equation: Carbon dioxide content in the flue gas stream varies from 10% to 15%. The flue gas stream may either be passed to the wastewater contained in the recarbonizers, or. enter the scrubbers (which are continually sprayed with wastewater) from the bottom in oountercurrent. The reactors, in which recarbonation occurs, have the ability to expand the contact surface between gaseous and liquid phase. This can be achieved by gas phase dispersion in the liquid phase (bubbling), by liquid phase dispersion in the gas phase (spraying), or by bubbling and spraying, and mixing. These concurrent operations are carried out during motion of the disk aerator (which is a patent claim). The authors describe the functioning of the disk aerator, the composition of the wastewater produced during wet gasification of carbide, the chemistry of recarbonation and decarbonation, and the concept of applying the disk aerator so as to make the wastewater fit for reuse (after suitable neutralization) as feeding water in acetylene generators.

New Approach to the Emission of Flue Gases Caused by Sludge Incineration in the Netherlands

1992 ◽  
Vol 25 (4-5) ◽  
pp. 307-314 ◽  
Author(s):  
A. W. van der Vlies ◽  
J. H. B. te Marvelde
Keyword(s):  
Sewage Sludge ◽  
The Netherlands ◽  
Flue Gas ◽  
Flue Gases ◽  
Gas Purification ◽  
Incineration Plant ◽  
New Approach ◽  
Sludge Incineration ◽  
Limited Degree ◽  
The Town

Recycling of sewage sludge will soon no longer be possible in The Netherlands, or will be possible only to a very limited degree. For that reason, part of the sewage sludge will have to be incinerated. This will happen particularly in those areas where tipping space is very limited. A sludge incineration plant is planned to be built in the town of Dordrecht, with a capacity of 45,000 tonnes dry solids per year. The plant will be subject to the very strict flue gas emission requirements of the Dutch Guideline on Incineration. The Guideline demands a sophisticated flue gas purification procedure.

scholarly journals Low-Cost Organic Adsorbents for Elemental Mercury Removal from Lignite Flue Gas

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2174
Author(s):  
Marta Marczak-Grzesik ◽  
Stanisław Budzyń ◽  
Barbara Tora ◽  
Szymon Szufa ◽  
Krzysztof Kogut ◽  
...  
Keyword(s):  
Flue Gas ◽  
Low Cost ◽  
Elemental Mercury ◽  
Mercury Content ◽  
Flue Gases ◽  
Mercury Removal ◽  
Gas Purification ◽  
Gas Temperature ◽  
Corn Straw ◽  
Flue Gas Purification

The research presented by the authors in this paper focused on understanding the behavior of mercury during coal combustion and flue gas purification operations. The goal was to determine the flue gas temperature on the mercury emissions limits for the combustion of lignites in the energy sector. The authors examined the process of sorption of mercury from flue gases using fine-grained organic materials. The main objectives of this study were to recommend a low-cost organic adsorbent such as coke dust (CD), corn straw char (CS-400), brominated corn straw char (CS-400-Br), rubber char (RC-600) or granulated rubber char (GRC-600) to efficiently substitute expensive dust-sized activated carbon. The study covered combustion of lignite from a Polish field. The experiment was conducted at temperatures reflecting conditions inside a flue gas purification installation. One of the tested sorbents—tire-derived rubber char that was obtained by pyrolysis—exhibited good potential for Hg0 into Hg2+ oxidation, resulting in enhanced mercury removal from the flue. The char characterization increased elevated bromine content (mercury oxidizing agent) in comparison to the other selected adsorbents. This paper presents the results of laboratory tests of mercury sorption from the flue gases at temperatures of 95, 125, 155 and 185 °C. The average mercury content in Polish lignite was 465 μg·kg−1. The concentration of mercury in flue gases emitted into the atmosphere was 17.8 µg·m−3. The study analyzed five low-cost sorbents with the average achieved efficiency of mercury removal from 18.3% to 96.1% for lignite combustion depending on the flue gas temperature.

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