Combustion Kinetics Characteristics of Solid Fuel in the Sintering Process

In order to systematically elucidate the combustion performance of fuel during sintering, this paper explores the influence of three factors, namely coal substitution for coke, quasi-particle structure and the coupling effect with reduction and oxidation of iron oxide, on fuel combustion characteristics, and carries out the kinetic calculation of monomer blended fuel (MBF) and quasi-granular fuel (QPF). The results show that replacing coke powder with anthracite can accelerate the whole combustion process. MBF and QPF are more consistent with the combustion law of the double-parallel random pore model. Although the quasi-particle structure increases the apparent activation energy of fuel combustion, it can also produce a heat storage effect on fuel particles, improve their combustion performance, and reduce the adverse effect of diffusion on the reaction process. In the early stage of reaction, the coupling between combustion of volatiles and reduction of iron oxide is obvious. The oxidation of iron oxide will occur again when the combustion reaction of fuel is weakened.

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Evaluation of Combustion Performance and Heat Release in Preheated Fuel Consumed Diesel Engines

Engineering Technologies and Systems ◽

10.15507/2658-4123.031.202103.349-363 ◽

2021 ◽

Vol 31 (3) ◽

pp. 349-363

Author(s):

Sergey А. Plotnikov ◽

Anatoly N. Kartashevich ◽

Marina V. Motovilova

Keyword(s):

Experimental Data ◽

Diesel Engine ◽

Heat Release ◽

Diesel Fuel ◽

Internal Combustion Engines ◽

Heating Temperature ◽

Combustion Process ◽

Thermal Action ◽

Fuel Combustion ◽

Combustion Performance

Introduction. The expansion of the fleet of tractors and vehicles causes increased requirements for internal combustion engines. This problem can be solved by improving the work process in a diesel engine that can be achieved by heating the diesel fuel in the fuel supply system. External thermal action is carried out on the high pressure line directly in front of the injectors. Materials and Methods. To analyze and calculate the process of combustion and heat release in a diesel engine with preliminary thermal fuel preparation, bench tests were carried out using the National Instruments software and the necessary equipment. Results. Experimental data of the diesel fuel combustion process in the cylinder of the 4CHN 11.0/12.5 engine are obtained. The analysis of the combustion performance and heat release of diesel with a preliminary high-temperature effect on the fuel was carried out. Indicator diagrams, graphs of heat release, the maximum average temperature of gases in the engine cylinder, and graphs of active and total heat release were constructed. The experimental data showed a decrease in the ignition delay period, the maximum cycle temperature in the engine cylinders, and an acceleration of the start of heat release and combustion process. The values of the parameters of the diesel fuel combustion process are obtained. Discussion and Conclusion. On the basis of the conducted studies, the dependences of the parameters of the combustion process of a diesel engine with fuel heating to high temperatures are revealed. Indicator diagrams allow drawing a conclusion about the influence of the fuel heating temperature on the intensification of the combustion process. There is an acceleration of the beginning of heat release, a decrease in the rate of pressure build-up and in the rigidity of the engine.

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Phase Formation during Reduction of Iron Sand with Soda Ash Flux Addition

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.264-265.801 ◽

2011 ◽

Vol 264-265 ◽

pp. 801-806

Author(s):

Pramusanto ◽

Hadi Purwanto ◽

Yuhelda Dahlan ◽

Nuryadi Saleh

Keyword(s):

Iron Oxide ◽

Magnetic Separation ◽

Sodium Titanate ◽

Oxide Phase ◽

Metallic Phase ◽

Magnetic Method ◽

Particle Structure ◽

Reduction System ◽

Reduction Of Iron ◽

Alkali Addition

Iron sand deposit in Indonesia generally consisted of titanomagnetite with ilmenite lamelaa occurred in magnetite particle structure, therefore direct physical separation through magnetic method at particle size of 400 mesh only capable increasing total iron content up to 60%. In order to increase the grade of iron, decreasing TiO2 content in iron sand was applied by chemical method of alkaline fusion followed by grinding to 100 mesh and magnetic separation. Pre-oxidation was conducted prior to reduction and alkaline flux was added to coal based reduction system of in a rotary kiln. The alkali addition into the reduction system resulted to the formation of metallic iron and non metallic phases, in which sodium titanate compounds as nonmagnetic product can be separated from calcine using separator magnetic. XRD analyses of the concentrate and tailing as magnetic separation products showed concentrate was dominated by metallic phase compared to oxide phase and it doesn’t consisted iron-titan oxide and iron oxide. On the other hand, tailing was consisted iron-titan oxide and iron oxide.

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Promoting Effect of Supports with Oxygen Vacancies as Extrinsic Defects on the Reduction of Iron Oxide

The Journal of Physical Chemistry C ◽

10.1021/acs.jpcc.1c04155 ◽

2021 ◽

Author(s):

Javier C. Mora ◽

Yoni C. M. Nederstigt ◽

Josephine M. Hill ◽

Sathish Ponnurangam

Keyword(s):

Iron Oxide ◽

Oxygen Vacancies ◽

Promoting Effect ◽

Reduction Of Iron ◽

Extrinsic Defects

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Chloride Diffusion Property of Hybrid Basalt–Polypropylene Fibre-Reinforced Concrete in a Chloride–Sulphate Composite Environment under Drying–Wetting Cycles

Materials ◽

10.3390/ma14051138 ◽

2021 ◽

Vol 14 (5) ◽

pp. 1138

Author(s):

Yang Luo ◽

Ditao Niu ◽

Li Su

Keyword(s):

Reinforced Concrete ◽

Coupling Effect ◽

Early Stage ◽

Polypropylene Fibre ◽

Chloride Diffusion ◽

Fibre Reinforcement ◽

Fibre Reinforced Concrete ◽

Basalt Fibre ◽

Diffusion Property ◽

Chloride Attack

The effect of fibre reinforcement on the chloride diffusion property of concrete is controversial, and the coupling effect of sulphate erosion and drying–wetting cycles in marine environments has been neglected in previous studies. In this study, the chloride diffusion property of hybrid basalt–polypropylene fibre-reinforced concrete subjected to a combined chloride–sulphate solution under drying–wetting cycles was investigated. The effects of basalt fibre (BF), polypropylene fibre (PF), and hybrid BP–PF on the chloride diffusion property were analysed. The results indicate that the presence of sulphate inhibits the diffusion of chloride at the early stage of erosion. However, at the late stage of erosion, sulphate does not only accelerate the diffusion of chloride by causing cracking of the concrete matrix but also leads to a decrease in the alkalinity of the pore solution, which further increases the risk of corrosion of the reinforcing steel. An appropriate amount of fibre can improve the chloride attack resistance of concrete at the early stage. With the increase in erosion time, the fibre effectively prevents the formation and development of sulphate erosion microcracks, thus reducing the adverse effects of sulphate on the resistance of concrete to chloride attack. The effects of sulphate and fibre on the chloride diffusion property were also elucidated in terms of changes in corrosion products, theoretical porosity, and the fibre-matrix interface transition zone.

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Determining the mass-related reaction effectiveness factor of large, nonspherical fuel particles for bridging between intrinsic and apparent combustion kinetics

Journal of Thermal Analysis and Calorimetry ◽

10.1007/s10973-019-09085-9 ◽

2019 ◽

Vol 141 (2) ◽

pp. 797-806 ◽

Cited By ~ 2

Author(s):

Tibor Szűcs ◽

Pal Szentannai

Keyword(s):

Combustion Process ◽

Effectiveness Factor ◽

Cfd Modeling ◽

Combustion Kinetics ◽

Kinetic Measurements ◽

Environmental Requirements ◽

Fuel Particles ◽

Related Reaction ◽

Kinetics Of ◽

Internal Pore

AbstractThe utilization of challenging solid fuels in the energy industry is urged by environmental requirements. The combustion kinetics of these fuel particles differs markedly from that of pulverized coal, mainly because of their larger sizes, irregular (nonspherical) shapes, and versatile internal pore structures. Although the intrinsic reaction kinetic measurements on very small amounts of finely ground samples of these particles are mostly available, a bridge toward their apparent reaction modeling is not evident. In this study, a method is introduced to build this bridge, the goodness of which was proved on the example of an industrially relevant biofuel. To do this, the results of a macroscopic combustion measurement with real samples in a well-modelable environment have to be used, and for considering some not negligible effects, 3D CFD modeling of the experimental environment is also to be applied. The outcome is the mass-related reaction effectiveness factor as a function of the rate of conversion. This variable can be considered as the active fraction of the entire particle mass on its periphery, and it can be used as the crucial element in modeling the combustion process of the same particle under other circumstances by including the actual boundary conditions. Another advantage of this method is its covering inherently the entire combustion process (water and volatile release, and char combustion) and also its applicability for reactors utilizing bigger particles like fluidized bed combustors.

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Effects of carbothermal reduction of iron oxide on microstructures and electrochemical properties of the carbon foams

Journal of Alloys and Compounds ◽

10.1016/j.jallcom.2021.161804 ◽

2021 ◽

pp. 161804

Author(s):

Zhuqi Wang ◽

Shenghui Deng ◽

Qiyun Zhang ◽

Jingze Li ◽

Qilang Lin

Keyword(s):

Iron Oxide ◽

Electrochemical Properties ◽

Carbothermal Reduction ◽

Reduction Of Iron ◽

Carbon Foams

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SIMULATION OF THE REDUCTION OF IRON-OXIDE POWDER BED BASED ON REACTIVITY OF CONSTITUENT POWDER AND DYNAMIC EFFECTIVE DIFFUSIVITY

JOURNAL OF CHEMICAL ENGINEERING OF JAPAN ◽

10.1252/jcej.12.130 ◽

1979 ◽

Vol 12 (2) ◽

pp. 130-136 ◽

Cited By ~ 1

Author(s):

YOSHIO NAKANO ◽

MASARU ISHIDA ◽

TAKASHI SHIRAI

Keyword(s):

Iron Oxide ◽

Effective Diffusivity ◽

Oxide Powder ◽

Powder Bed ◽

Reduction Of Iron

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SPECTRAL DIAGNOSTICS OF THE HYDROCARBON FUEL COMBUSTION PROCESS

Kontrol Diagnostika ◽

10.14489/td.2021.10.pp.012-017 ◽

2021 ◽

pp. 12-17

Author(s):

M. A. Vaganov

Keyword(s):

Combustion Process ◽

Hydrocarbon Fuel ◽

Combustion Products ◽

Combustible Mixture ◽

Fuel Combustion ◽

Propane Combustion ◽

Gaseous Hydrocarbon ◽

Spectral Bands ◽

Air Supply ◽

Spectral Diagnostics

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.

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