scholarly journals Transformations of mercury in processes of solid fuel combustion – review

2017 ◽  
Vol 43 (4) ◽  
pp. 82-93 ◽  
Author(s):  
Marianna Czaplicka ◽  
Halina Pyta
Keyword(s):  
Elemental Mercury ◽  
Solid Particles ◽  
Heterogeneous Reactions ◽  
Active Components ◽  
Exhaust Gases ◽  
Homogeneous Oxidation ◽  
Mercury Fractionation ◽  
Solid Fuel Combustion ◽  
Combustion Of Solid Fuels ◽  
Mechanisms Of Reactions

AbstractThe paper presents current reports on kinetics and mechanisms of reactions with mercury which take place in the exhaust gases, discharged from the processes of combustion of solid fuels (coals). The three main stages were considered. The first one, when thermal decomposition of Hg components takes place together with formation of elemental mercury (Hg0). The second one with homogeneous oxidation of Hg0to Hg2+by other active components of exhaust gases (e.g. HCl). The third one with heterogeneous reactions of gaseous mercury (the both - elemental and oxidised Hg) and solid particles of fl y ash, leading to generation of particulate-bound mercury (Hgp). Influence of exhaust components and their concentrations, temperature and retention time on the efficiency of mercury oxidation was determined. The issues concerning physical (gas-solid) and chemical speciation of mercury (fractionation Hg0-Hg2+) as well as factors which have influence on the mercury speciation in exhaust gases are discussed in detail.

scholarly journals Assessment of Environmental Risks of Particulate Matter Emissions from Road Transport Based on the Emission Inventory

2021 ◽  
Vol 11 (13) ◽  
pp. 6123
Author(s):  
Katarzyna Bebkiewicz ◽  
Zdzisław Chłopek ◽  
Hubert Sar ◽  
Krystian Szczepański ◽  
Magdalena Zimakowska-Laskowska
Keyword(s):  
Particulate Matter ◽  
Legal Status ◽  
Monitoring And Evaluation ◽  
Road Transport ◽  
Solid Particles ◽  
Pollutant Emissions ◽  
European Economic Area ◽  
Engine Exhaust ◽  
Exhaust Gases ◽  
Particulate Matter Emissions

The aim of this study is to investigate the environmental hazards posed by solid particles resulting from road transport. To achieve this, a methodology used to inventory pollutant emissions was used in accordance with the recommendations of the EMEP/EEA (European Monitoring and Evaluation Programme/European Economic Area). This paper classifies particulates derived from road transport with reference to their properties and sources of origin. The legal status of environmental protection against particulate matter is presented. The emissions of particulate matter with different properties from different road transport sources is examined based on the results of Poland’s inventory of pollutant emissions in the year 2018. This study was performed using areas with characteristic traffic conditions: inside and outside cities, as well as on highways and expressways. The effects of vehicles were classified according to Euro emissions standards into the categories relating to the emissions of different particulate matter types. The results obtained showed that technological progress in the automobile sector has largely contributed to a reduction in particulate matter emissions associated with engine exhaust gases, and that this has had slight effect on particulate matter emissions associated with the tribological processes of vehicles. The conclusion formed is that it is advisable to undertake work towards the control and reduction of road transport particulate matter emissions associated with the sources other than engine exhaust gases.

scholarly journals COMBUSTION SPEED PARAMETERS WHEN SIMULATING BY ANSYS FLUENT PROGRAM OF SOLID FUEL COMBUSTION

2020 ◽  
pp. 41-45
Author(s):  
M.M. Nekhamin ◽  
D.L. Bondzyk
Keyword(s):  
Burning Rate ◽  
Solid Fuel ◽  
Cfd Modeling ◽  
Solid Fuels ◽  
Ansys Fluent ◽  
Solid Fuel Combustion ◽  
The Difference ◽  
Fuel Particles ◽  
Combustion Of Solid Fuels ◽  
Combustion Speed

The existing difference in the models used to describe the burning rate of solid fuel particles, and, accordingly, the difference in the constants appearing in them, determines the relevance of the formulation of the relation between the constants known from the literature and the parameters that must be set in programs for CFD modeling of heat and power processes. This, in particular, relates to modeling the combustion of solid fuels in the well-known program ANSYS FLUENT. The paper outlines a possible approach to solving this problem. Bibl. 5, Fig. 3.

scholarly journals NUMERICAL SIMULATING THE CHEMICAL INTERACTION OF FLUID WITH ROCK AT THE PORE SCALE

2021 ◽  
Vol 2 (3) ◽  
pp. 46-54
Author(s):  
Tatyana S. Khachkova ◽  
Vadim V. Lisitsa
Keyword(s):  
Porous Medium ◽  
Fluid Flow ◽  
Reactive Transport ◽  
Chemical Interaction ◽  
Pore Space ◽  
Heterogeneous Reactions ◽  
Pore Scale ◽  
Active Components ◽  
Flow And Transport ◽  
The Finite Difference Method

The article presents a numerical algorithm for modeling the chemically reactive transport in a porous medium at a pore scale. The aim of the study is to research the change in the geometry of the pore space during the chemical interaction of the fluid with the rock. First, fluid flow and transport of chemically active components are simulated in the pore space. Heterogeneous reactions are then used to calculate their interactions with the rock. After that, the change in the interface between the liquid and the solid is determined using the level-set method, which allows to handle changes in the topology of the pore space. The algorithm is based on the finite-difference method and is implemented on the GP-GPU.

scholarly journals Evaluated kinetic and photochemical data for atmospheric chemistry: Volume V – heterogeneous reactions on solid substrates

2010 ◽  
Vol 10 (2) ◽  
pp. 5233-5564 ◽  
Author(s):  
J. N. Crowley ◽  
M. Ammann ◽  
R. A. Cox ◽  
R. G. Hynes ◽  
M. E. Jenkin ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Kinetic Data ◽  
Solid Particles ◽  
Heterogeneous Reactions ◽  
Detailed Data ◽  
Adsorption Parameters ◽  
Solid Substrates ◽  
Heterogeneous Processes ◽  
Acid Hydrate ◽  
Sulfuric Acid Hydrate

Abstract. This article, the fifth in the ACP journal series, presents data evaluated by the IUPAC Subcommittee on Gas Kinetic Data Evaluation for Atmospheric Chemistry. It covers the heterogeneous processes on surfaces of solid particles present in the atmosphere, for which uptake coefficients and adsorption parameters have been presented on the IUPAC website in 2009. The article consists of an introduction and guide to the evaluation, giving a unifying framework for parameterisation of atmospheric heterogeneous processes. We provide summary sheets containing the recommended uptake parameters for the evaluated processes. Four substantial appendices contain detailed data sheets for each process considered for ice, mineral dust, sulfuric acid hydrate and nitric acid hydrate surfaces, which provide information upon which the recommendations are made.

scholarly journals Numerical Study on the Homogeneous Reactions of Mercury in a 600 MW Coal-Fired Utility Boiler

Energies ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 446
Author(s):  
Qiang Lyu ◽  
Chang’an Wang ◽  
Xuan Liu ◽  
Defu Che
Keyword(s):  
Power Plants ◽  
Numerical Study ◽  
Elemental Mercury ◽  
Mercury Chloride ◽  
Homogeneous Oxidation ◽  
First Time ◽  
Chlorine Corrosion ◽  
Quantitative Contributions ◽  
Hg Pollution ◽  
Homogeneous Reactions

The homogeneous oxidation of elemental mercury (Hg0) can promote Hg pollution control in coal-fired power plants, while the mechanisms and quantitative contributions of homogeneous reactions in Hg0 oxidation, especially the reactions between Hg and chlorine (Cl), are still unclear. Here, a numerical study on the homogeneous reactions of Hg was conducted within a 600 MW tangentially fired boiler for the first time. A novel Hg sub-model was established by coupling the thermodynamics, reaction kinetics and fluid dynamics. The results showed that the higher Cl content in coal was beneficial to the oxidation of Hg0. The homogeneous reactions of Hg mainly occurred in the vertical flue pass at low temperature. Hg0 was still the dominant Hg-containing species at the boiler exit, and the concentration of mercury chloride (HgCl2) was the highest among the oxidized mercury. When low-Cl coal was fired, the addition of a small amount of chlorine species into the boiler at the burnout area increased the ratio of HgCl2 by over 16 times without causing serious chlorine corrosion problems.

scholarly journals Effect of sea-salt aerosol on tropospheric bromine chemistry

2018 ◽  
Author(s):  
Lei Zhu ◽  
Daniel J. Jacob ◽  
Sebastian D. Eastham ◽  
Melissa P. Sulprizio ◽  
Xuan Wang ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Marine Boundary Layer ◽  
Elemental Mercury ◽  
Sea Salt ◽  
Heterogeneous Reactions ◽  
Tropospheric Chemistry ◽  
Sulfur Species ◽  
Sea Salt Aerosol ◽  
Volatile Organic ◽  
First Time

Abstract. Bromine radicals influence global tropospheric chemistry by depleting ozone and OH, and by oxidizing elemental mercury, sulfur species, and volatile organic compounds. Observations typically indicate a 50 % depletion of sea salt aerosol (SSA) bromide relative to seawater composition, implying that SSA debromination could be the dominant global source of tropospheric bromine. However, it has been difficult to reconcile this large source with the relatively low BrO concentrations observed in the marine boundary layer (MBL). Here we present a new mechanistic description of SSA debromination in the GEOS-Chem global atmospheric chemistry model with a detailed representation of halogen (Cl, Br, and I) chemistry. We show, for the first time, observed levels of SSA debromination can be reproduced in a manner consistent with observed BrO concentrations. Bromine radical sinks from the HOBr + S(IV) heterogeneous reactions and from ocean emission of acetaldehyde are found to be critical in moderating tropospheric BrO levels. The resulting HBr is rapidly taken up by SSA and also deposited. We find that the source of bromine radicals is mostly from SSA in the MBL, but from organobromines in the free troposphere. Simulated BrO in the MBL is generally much higher in winter than in summer due to a combination of greater SSA emission and weaker radiation. Outstanding issues are the model underestimate of free tropospheric BrO, driven by the HOBr + S(IV) reactions, and uncertainty regarding HBr uptake by SSA.

scholarly journals On the issue of reducing the negative impact of nitrogen oxides in the system recirculation of diesel exhaust gases on applying the vortex effect

2020 ◽  
Vol 221 ◽  
pp. 02006
Author(s):  
Irina Belinskaia ◽  
Rahim Zainetdinov ◽  
Konstantin Evdokimov
Keyword(s):  
Nitrogen Oxides ◽  
Internal Combustion Engines ◽  
Negative Impact ◽  
Exhaust System ◽  
Internal Combustion ◽  
Solid Particles ◽  
Combustion Engines ◽  
Exhaust Gases ◽  
Advantages And Disadvantages ◽  
Vortex Effect

The problem of negative impact on the environment of motor transport is one of the most fundamental in the complex of global problems. The constant increase in the number of cars with internal combustion engines encourages the search for methods and ways to reduce the volume of negative impulses. The operation of heat engines is accompanied by significant emissions of gaseous harmful substances into the atmosphere, i.e. nitrogen oxides, carbon monoxide, hydrocarbons, as well as solid particles, including soot. The solution to this problem should be implemented within the framework of a systematic approach. To do this, it is necessary to combine the study of technical, economic, and organizational approaches to the organization of the exhaust gas disposal process. To date, there is a significant methodological base in the field of organizational and economic decisions. The article discusses various methods of cleaning exhaust gases of piston engines, their advantages and disadvantages are noted. The method of processing using ammonia is widely known. It is noted that a catalytic method for reducing nitrogen oxides using ammonia is quite economical. However, the optimal temperature range at which nitrogen oxides are reduced is rather narrow. To solve this problem, it is proposed to use the vortex effect in the exhaust system. The efficiency of using a vortex gas recirculation pipe is due to its significant influence on the thermal gasdynamic processes occurring in the exhaust system. Using the principles of non-equilibrium thermodynamics allows us to take into account dissipative processes when establishing the relationship of fuel and economic indicators of internal combustion engines with thermodynamic parameters. This significantly increases the accuracy of calculations and allows you to develop measures to reduce the level of negative impact on the environment.

scholarly journals Removal of Elemental Mercury from Flue Gas using the Magnetic Attapulgite by Mn-Cu Oxides Modification

2021 ◽  
Author(s):  
Yifei Long ◽  
Zhong He ◽  
Xiaoyi Li ◽  
Yajie Yin ◽  
Yuan Wang ◽  
...  
Keyword(s):  
Removal Efficiency ◽  
Flue Gas ◽  
Active Sites ◽  
Chemical Properties ◽  
Elemental Mercury ◽  
Mercury Removal ◽  
Impregnation Method ◽  
Active Components ◽  
Co Precipitation ◽  
Physical And Chemical

Abstract Mercury pollution has become one of the most concerned environmental issues in the world because of its high toxicity, non-degradability and bioaccumulation. Attapulgite adsorbents modified by magnetic manganese-copper (MnxCuy-MATP) were fabricated by co-precipitation and ultrasonic impregnation method,aiming at removing Hg0 from coal-fired flue gas. BET, SEM, XRD, VSM and XPS were used to systematically explore the physical and chemical properties of the adsorbents, the effects of manganese and copper additions, reaction temperature and various components in the flue gas on the efficiency of Hg0 removal were investigated. Mn8Cu5-MATP exhibited the optimal properties, and excessive copper loadings led to the aggregation of the active components. The efficiency of mercury removal can be effectively improved by NO and HCl regardless of the absence and presence of O2, because the NO+, NO3, NO2 and Cl* produced during the reaction can promote the adsorption and oxidation of Hg0. SO2 and H2O inhibited the oxidation of Hg0 because of the competitive adsorption at the active sites, while a large amount of sulfite and sulfate were formed to block the pores. However, the introduction of copper caused the sample to obtain SO2 resistance, which resulted in a mercury removal efficiency of 84.3% even under 1500 ppm SO2. In addition, after 5 cycles of adsorption and regeneration, Mn8Cu5-MATP can still maintain excellent Hg0 removal ability. The fabricated adsorbent can save the actual production cost and effectively improve the mercury removal efficiency in sulfur-containing flue gas.

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