scholarly journals Effects of Catalysts on Emissions of Pollutants from Combustion Processes of Liquid Fuels

2014 ◽  
Vol 13 (2) ◽  
pp. 5-17
Author(s):  
Agnieszka Bok ◽  
Joanna Guziałowska-Tic ◽  
Wilhelm Jan Tic

Abstract The dynamic growth of the use of non-renewable fuels for energy purposes results in demand for catalysts to improve their combustion process. The paper describes catalysts used mainly in the processes of combustion of motor fuels and fuel oils. These catalysts make it possible to raise the efficiency of oxidation processes simultanously reducing the emission of pollutants. The key to success is the selection of catalyst compounds that will reduce harmful emissions of combustion products into the atmosphere. Catalysts are introduced into the combustion zone in form of solutions miscible with fuel or with air supplied to the combustion process. The following compounds soluble in fuel are inclused in the composition of the described catalysts: organometallic complexes, manganese compounds, salts originated from organic acids, ferrocen and its derivatives and sodium chloride and magnesium chloride responsible for burning the soot (chlorides). The priority is to minimize emissions of volatile organic compounds, nitrogen oxides, sulphur oxides, and carbon monoxide, as well as particulate matter.

Author(s):  
A. M. Dostiyarov ◽  
D. R. Umishev ◽  
G. B. Saduakasova ◽  
A. K. Mergalimova ◽  
B. Ongar

The issues of combustion processes and the organization of the combustion workflow in diesel engines are relevant in view of the tightening of economic and environmental requirements for them. The problem of saving liquid fuels remains one of the most acute in the provision of fuel and energy resources. The development of highly efficient methods for organizing work processes when burning natural gas in a compressed or cryogenic state in the cylinders of internal combustion piston engines and determining ways to further reduce toxic emissions, increase fuel efficiency and reliability in promising gas engines is an urgent task. Mathematical modeling of liquid fuel combustion is a complex task, since it requires taking into account a large number of complex interrelated processes and phenomena. The article presents a simple 3-D model of cylinder diesel tractor engine D 144, the re- sults of numerical simulation of combustion of liquid and gaseous fuel in the cylinder of the diesel engine D-144. The article presents the results of modeling, including graphs of the dependence of nitrogen oxides, particles in outgoing gases, depending on the consumption of gaseous fuel in the form of pure methane. Additionally, tempe- rature and velocity contours are shown. The corresponding conclusions are made.


2020 ◽  
Vol 2020 (1) ◽  
pp. 19-27
Author(s):  
J Khakimov ◽  
◽  
M Shatrov ◽  
J Turdiev

The article considers the investigation results of the working process of diesel on light fuel. Consumption of natural resources in the form of hydrocarbon fuels, which is steadily increasing in transport, the number of rolling stock, and combustion products of motor fuels cause environmental pollution. It is shown that the transition to cheaper alternative types of fuel, by its characteristics, not inferior to liquid motor fuels, is one of the options to reduce operating costs and harmful emissions. The scheme of classification of gas systems of fuel transfer is presented: by design of the system of filling and storage of gas; by quantity of the substituted basic fuel in the system of fuel supply; by method of dosing of fuel; by name and place of sending of a control signal; by design of the unit of decrease in pressure of gas; by design and a site of heating devices of a gas stream of a high pressure; by a method of ignition of a gas-air mix; by a method of change of indicators of working process; by an aggregate condition of used According to the results of theoretical and operational research of the gas engine based on a supercharged diesel engine: the necessity of using a gas injector power supply system has been established; the power and torque of the gas engine created on the basis of a supercharged diesel engine practically do not differ from that of the diesel engine, which is explained by a relatively high degree of compression for engines with spark ignition (ε=2); it has been shown that in the long term it is possible to use gas supply systems under pressure directly into the engine cylinder. As a result, the most affordable commercial alternative fuel for road transport in Uzbekistan turned out to be natural gas.


Author(s):  
K.M. Hall ◽  
X. Fu ◽  
K. Brezinsky

With the intent of optimizing the combustion process of complex hydrocarbon liquid fuels such as JP8 in internal combustion jet engines and their afterburners, simpler surrogate hydrocarbon compounds were used in a counterflow diffusion flat flame burner to validate the chemical kinetic modeling process. The combustion products sampled from the flame produced during the burning of the validation fuels methane and n-heptane were analyzed using a Varian CP3800 gas chromatograph. The effects of sampling with a 350 micron outer diameter (OD) fused-silica tube were compared to those of a 3.5 mm quartz probe in order to minimize sampling effect on the flame. Simulations of the sampled species were performed using the OPPDIF package of CHEMKIN with chemistry models provided by UIC. Concentrations of major species (e.g. CO, CH4, CO2, O2) were found to be well simulated with the models, with the best fit occurring for methane and n-heptane, and wider variation occurring with some species in all validation fuels.


2014 ◽  
Vol 3 (1) ◽  
pp. 20-31
Author(s):  
Branko Lalić ◽  
Ivan Komar ◽  
Danilo Nikolić

Impacts of exhaust gas emissions on the environment and air pollution from ships have received considerable attention in the past few decades. Due to the characteristics of the combustion process, typical for large marine two-stroke low-speed engines, and the use of residual fossil fuels, the world’s fleet emits into the atmosphere significant amount of pollutants such as nitrogen oxides (NOx), carbon monoxide (CO), carbon dioxide (CO2), hydrocarbons (HC), sulphur oxides (SOx) and carbon particles (PM). Impact assessment of the process of their formation, emitted amounts and the influence of emission are important factors for decision making in regulation development and also for engine designers who aim to improve low-speed two-stroke marine engines, for further tightening of regulations regarding limiting emissions. This paper consists of three parts: the first section describes the injection and combustion process in lowspeed two-stroke marine engines, the second part describes the formation of the exhaust as emissions as a product of the combustion process and the third part, in which the known techniques to reduce harmful emissions that are currently used in low-speed two-stroke marine engines are described.


Author(s):  
O. S. Gaydukova ◽  
◽  
D. O. Glushkov ◽  
A. G. Nigay ◽  
A. G. Kosintsev ◽  
...  

Recently, prospective direction of the combustion theory development is the preparation of fuel compositions and study of the composite fuels ignition characteristics, for example, in the form of emulsions and suspensions. Such fuels and their combustion processes are characterized by higher environmental, energy, economic, and operational properties. Of great interest is the use of gel fuels prepared by thickening emulsions and suspensions to the state of elastically deformable materials for the aerospace industry and thermal power engineering. Gel fuels have advantages over widespread liquid fuels in environmental and fire safety aspects of storage processes, transportation, and combustion.


2021 ◽  
pp. 12-17
Author(s):  
M. A. Vaganov

It is proposed to use the methods of applied optical spectroscopy to solve the problem of control and diagnostics of gaseous hydrocarbon fuel combustion in this work. The results of an experimental study of spectroscopic informative parameters characterizing the propane combustion process are presented for three modes: combustion of pure propane without air supply, stoichiometric combustion and combustion with a change in the amount of supplied air relative to stoichiometric combustion. As a result of the experiment, it was found that the most intense bands in the emission spectrum of the flame arising from the combustion of propane correspond to the spectral bands of radicals of combustion products: OH, CH, and C2. While the intensities of various systems of bands in the flame spectrum depend significantly on the composition of the combustible mixture.


2019 ◽  
Vol 97 (11) ◽  
pp. 795-804 ◽  
Author(s):  
Dong Xiang ◽  
Weihua Zhu

The density functional tight-binding molecular dynamics approach was used to study the mechanisms and kinetics of initial pyrolysis and combustion reactions of isolated and multi-molecular FOX-7. Based on the thermal cleavage of bridge bonds, the pyrolysis process of FOX-7 can be divided into three stages. However, the combustion process can be divided into five decomposition stages, which is much more complex than the pyrolysis reactions. The vibrations in the mean temperature contain nodes signifying the formation of new products and thereby the transitions between the various stages in the pyrolysis and combustion processes. Activation energy and pre-exponential factor for the pyrolysis and combustion reactions of FOX-7 were obtained from the kinetic analysis. It is found that the activation energy of its pyrolysis and combustion reactions are very low, making both take place fast. Our simulations provide the first atomic-level look at the full dynamics of the complicated pyrolysis and combustion process of FOX-7.


2017 ◽  
Vol 21 (suppl. 3) ◽  
pp. 705-716 ◽  
Author(s):  
Barbara Vidakovic ◽  
Milos Banjac

This paper, dealing with the problems of mathematical description of the tunnel fire development process with the use of experimental data, outlines the procedure of correction of the existing and obtaining of an improved CFD model package. The improved CFD model was developed on the basis of detailed analysis and comparison of experimental and numerical results, through consideration of the physical structure of all processes affecting combustion. During the analysis it was noticed that the existing CFD model in the part covering combustion based on the so-called steady laminar flamelet model, treats the combustion process almost as a direct correlation between the processes of mixing gasses and heat release rate. This potential deficiency has been overcome by correction of the model in the section defining boundary condition for the burning surface and by establishing a direct correlation between the measured value of the fuel mass change rate and the amount of heat released from burning surface. In this way a modification of complex stoichiometric combustion processes was avoided, while providing the model that better describes and predicts the course of events in this type of complex, anisotropic and turbulent flow of gases in the tunnel.


2013 ◽  
Vol 64 (1) ◽  
Author(s):  
Mohammad Nazri Mohd. Jaafar ◽  
Mohd Nur Hanafi Zaini

Emission from the combustion processes can cause adverse effect to the environment.  The formation of pollutants such as NOx, CO, CO2 and SOx are hazardous and harmful to the ecosystem.  The awareness about the pollution due to the combustion activities, particularly in industrial field has set off an effort to find more comprehensive and enhanced technologies to reduce these pollutants.  There are several methods that can be used to reduce the emissions of these pollutants either by combustion modifications or post combustion treatment.  In this research, the method used is the post combustion treatment, i.e. the air staging method.  By air staging techniques, some of the combustion air will be directed into the primary combustion zone, while the remaining air is directed into the secondary zone.  The function of the secondary air is to reduce the peak flame temperatures, which theoretically reduce the emissions of NOx emissions.  The primary concern for this research is to study the effectiveness of the air staging in reducing NOx, CO, SO2, and UHC emissions from the combustion process.  The results obtained showed significant reduction in all major pollutants, i.e., a 31.8 percent reduction for CO emission, 16.8 percent for NOx, 12.7 percent for SO2 and 10.3 percent for UHC.  These reductions were obtained at different equivalence ratios for different gases.


2019 ◽  
Vol 4 (2) ◽  
pp. 154-162
Author(s):  
Lin Li ◽  
Fedor Gubarev ◽  
Andrei Mostovshchikov ◽  
Alexander Ilyin

The paper is devoted to development of methods for studying the dynamics of high-temperature combustion of aluminum nanopowder.The difficulty in studying the combustion of nanopowders is the high temperature and intensity of light emissionduring the combustion process, which makes the visual observation virtually impossible.The paper discusses various schemes using laser radiation to study the combustion processes of metal nanopowders.Particular mentions the use of the laser monitor based on an active medium on copper bromide vapor to study the combustion process of various powders and mixtures.The laser monitor combines the functions of the narrow-band laser illuminator and the brightness amplifier, thereby achieving the visualization at a narrow gain wavelength. Therefore, the laser monitor can be used to observe the changes in the surface of a burning sample with high temporal and spatial resolution.


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