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 SIMULATION OF BIOGAS COMBUSTION IN INJECTION BURNER WITH HEAT DIVIDER

2020 ◽  
pp. 40-47
Author(s):  
D. Suslov ◽  
R. Ramazanov
Keyword(s):  
Software Package ◽  
Flame Temperature ◽  
Combustion Process ◽  
Methane Content ◽  
Ansys Fluent ◽  
Preliminary Heating ◽  
Injection Burner ◽  
Modeling Software

The purpose of this work is to develop a design of a biogas combustion equipped with a thermal divider and study the process of burning biogas of different composition. To study the biogas combustion process in the burner of the developed design, the Ansys Fluent modeling software package is used. An injection burner for biogas combustion with a cone-shaped thermal divider and primary air regulator has been developed. Studies of the process of burning biogas of different composition in burners of 5 designs were carried out: without a divider, with a divider with a length of L = 6 mm, with a divider L = 12 mm, with a divider L = 18 mm and a divider L = 24 mm. As a result of modeling, it is found that the placement of a divider with a length of 6 mm and 12 mm does not affect the temperature of the gas-air mixture in the burner body. Increasing the length of the divider to 18 mm allows to increase the temperature of the flow of the gas-air mixture passing along the divider. A further increase in the length of the divider to 24 mm leads to a slight increase in the temperature of the gas-air mixture. The dependences of the flame temperature on the length of the divider during the combustion of biogas with a methane content of 60% and 70% are obtained. When a divider with a length of 6 mm and 12 mm is placed in the burner body, the flame temperature decreases, with an increase in the length of the divider to 18 mm, the flame temperature increases, and with an increase in the length of the divider to 24 mm, the flame temperature remains practically unchanged. Consequently, the placement of a divider with a length of 18 ... 24 mm in the burner body ensures preliminary heating of the gas-air mixture and allows increasing the efficiency of the biogas combustion process.

scholarly journals The Prototype of Non-thermal Plasma After treatment System for Simultaneous Reduction of Nitrogen Oxide Emission in Flue Gas

2021 ◽  
Vol 302 ◽  
pp. 01010
Author(s):  
Dararat Laohalertdecha ◽  
Kampanart Theinnoi ◽  
Sak Sittichompoo
Keyword(s):  
Nitrogen Oxides ◽  
Nitrogen Oxide ◽  
Flue Gas ◽  
Thermal Plasma ◽  
Power Plants ◽  
Gas Flow ◽  
Nox Reduction ◽  
Combustion Process ◽  
Operating Conditions ◽  
Non Thermal Plasma

Nowadays, global warming is the main environmental problems all over the world. The air pollutants mainly from the burning of fossil fuels and coal in power plants, transportation, and automobiles. There are release major point emission of the atmosphere. The nitrogen oxides are the most relevant for air pollution that contribute to the formation of photochemical smog and acid rain. Numerous methods have been studied to eliminate the nitrogen oxides such as the use low-nitrogen fuels technology, the selective catalytic reduction (SCR), wet scrubbing. The aim of this research is investigated non-thermal plasma (NTP) techniques offer an innovation to eliminate both nitrogen oxide (NOx) and soot emissions from combustion. This study is used to selectively transfer input electrical energy to electrons without expending this in heating the entire gas flow which creates free radicals in the flue gases. The simulated flue gas from combustion process is applied to the system. The results showed that the prototype of nonthermal plasma system is shown the highly efficient of NOx removal was achieved. However, the optimised of NTP operating conditions are required to enhance the NOx reduction activities.

A review on the removal of nitrogen oxides from polluted flow by bioreactors

2010 ◽  
Vol 18 (NA) ◽  
pp. 175-189 ◽  
Author(s):  
Hejingying Niu ◽  
D.Y.C. Leung
Keyword(s):  
Nitric Oxide ◽  
Nitrogen Oxides ◽  
Tropospheric Ozone ◽  
Catalytic Reduction ◽  
Combustion Process ◽  
Energy Requirements ◽  
Exhaust Gas ◽  
Process Energy ◽  
Combustion Processes ◽  
Harmful Effects

Nitric oxide (NO) and nitrogen dioxide (NO2) are the main pollutants of nitrogen oxides (NOx) released during a combustion process. They induce harmful effects both to the environment and human health, such as the formation of acid rain, an increase of the tropospheric ozone, global warming, etc. Selective catalytic reduction, selective non-catalytic reduction, adsorption and scrubbing (absorption) are the conventional technologies used to control NOx emission from exhaust gas. The bioreactor appears superior to conventional technologies in terms of simplicity and economy in operation, low process energy requirements, and easy treatment of residual products. This paper reviews two biologically-based NOx removal theories, i.e., nitrification and denitrification. The use of bacteria, fungi and microalgae are discussed and compared. The study indicates that the bioreactor is a promising technology that can be used to control NOx emitted during combustion processes.

Study of Combustion Characteristics of Ethanol at Different Dilution With the Carrier Gas

2014 ◽  
Author(s):  
Binash Imteyaz ◽  
Mohamed A. Habib
Keyword(s):  
Carbon Dioxide ◽  
Flue Gas ◽  
Carbon Capture ◽  
Liquid Fuel ◽  
Flame Temperature ◽  
Combustion Process ◽  
Combustion Efficiency ◽  
Combustion Characteristics ◽  
Conventional Combustion ◽  
Gas Volume

With the ever rising concern of global warming, carbon capture is gaining the reputation of one of the most challenging fields of research. A very promising technology to capture CO2 is oxy-combustion. Oxy-combustion offers several advantages over conventional combustion technologies, such as flue gas volume reduction, high combustion efficiency, low fuel consumption and significant reduction in NOx emissions. Liquid fuel is available and it is the most widely used source of energy in the world. Easy handling and transportation, less storage volume and higher flame temperature are some of the features of liquid fuel which give it an upper hand over other sources. In this study, an experimental work on oxygen enriched combustion of ethanol in a vertical reactor by Lacas F. et. al. has been modeled numerically. Non-premixed model using Probability Density Function has been incorporated to simulate the combustion process of ethanol droplets. Predicted combustion characteristics are found to be in good compliance with the experimental data. In addition to this, effects of dilution of carbon-dioxide in oxygen on the flame properties have also been presented. Combustion of ethanol in oxygen-carbon dioxide environment has been compared with that of the conventional air environment.

Study of Combustion Characteristics of Ethanol at Different Dilution With the Carrier Gas

2015 ◽  
Vol 137 (3) ◽  
Author(s):  
Binash Imteyaz ◽  
Mohamed A. Habib
Keyword(s):  
Carbon Dioxide ◽  
Flue Gas ◽  
Carbon Capture ◽  
Liquid Fuel ◽  
Flame Temperature ◽  
Combustion Process ◽  
Combustion Efficiency ◽  
Combustion Characteristics ◽  
Gas Volume ◽  
Probability Density Function Pdf

With the ever-rising concern of global warming, carbon capture is gaining the reputation of one of the most challenging fields of research. A very promising technology to capture CO2 is oxy-combustion. Oxy-combustion offers several advantages over conventional combustion technologies, such as flue–gas volume reduction, high combustion efficiency, low fuel consumption, and significant reduction in NOx emissions. Liquid fuel is available and it is the most widely used source of energy in the world. Easy handling and transporting, less storage volume and higher flame temperature are some of the features of liquid fuel which give it an upper hand over other sources. In this study, an experimental work on oxygen enriched combustion of ethanol in a vertical reactor by Lacas et al. (2005, “Experimental Study of Air Dilution in Oxy-Liquid Fuel Flames,” Proc. Combust. Inst., 30(2), pp. 2037–2045) has been modeled numerically. Nonpremixed model using probability density function (PDF) has been incorporated to simulate the combustion process of ethanol droplets. Predicted combustion characteristics are found to be in good compliance with the experimental data. In addition to this, effects of dilution of carbon dioxide in oxygen on the flame properties have also been presented. Combustion of ethanol in oxygen–carbon dioxide environment has been compared with that of the conventional air environment.

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 THE STUDY AND THE MECHANISM OF NITROGEN OXIDES’ FORMATION IN COMBUSTION OF FOSSIL FUELS

2018 ◽  
Vol 16 (2) ◽  
pp. 273 ◽  
Author(s):  
Bulbul Ongar ◽  
Iliya K. Iliev ◽  
Vlastimir Nikolić ◽  
Aleksandar Milašinović
Keyword(s):  
Nitric Oxide ◽  
Nitrogen Oxides ◽  
Coal Combustion ◽  
Fossil Fuels ◽  
Coal Dust ◽  
Chemical Reduction ◽  
Molecular Nitrogen ◽  
Combustion Process ◽  
Nitric Oxides ◽  
Nitric Oxide Emissions

The burning of all fossil fuels is accompanied by the production of large quantities of nitrogen oxides. Nitrogen oxide from coal combustion is formed from the molecular nitrogen in the air and the nitrogen contained in the fuel. In accordance with the mechanism of formation of nitric oxide from fuel, it is desirable to increase the concentration of coal dust in the flame. The thermal regime of combustion accelerates the release of volatiles, with flames spreading out and the coke residue contributes to the chemical reduction of NOx. In this work we consider the specific issues of the formation mechanism of NOx fuel and ways to reduce their atmospheric emissions. Presented are results from the calculation of the influence of the following on the level of nitric oxides during coal combustion: temperature, oxygen concentration and time of release of fuel nitrogen. It has been established that the influence of nitric oxide fuel on the total nitric oxide emissions is more noticeable at low temperatures of the combustion process.

Reducing the Formation of Secondary Pollutants in the Process of NonCatalytic Purification of Flue Gases from Nitrogen Oxides

2020 ◽  
Vol 24 (7) ◽  
pp. 8-11
Author(s):  
O.N. Kulish ◽  
K.I. Zaporozhskiy ◽  
S.A. Kuzhevatov ◽  
M.N. Orlova ◽  
V.M. Senyavin ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Thermal Decomposition ◽  
Carbon Monoxide ◽  
Nitrogen Oxides ◽  
Catalytic Reduction ◽  
Flue Gases ◽  
Decomposition Products ◽  
Secondary Pollutants ◽  
Thermal Decomposition Products

The possibilities of the technology of non-catalytic reduction of nitrogen oxides (SNCR) to reduce the possible formation of secondary pollutants: ammonia, carbon monoxide and nitric oxide (I) are considered. The conditions for the process of reduction of nitrogen oxides by the thermal decomposition products of urea with a minimum formation of the above pollutants are determined.

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