Journal articles: 'Combustion air preheating'

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Fan, Min Hui, Guan Qing Wang, Dan Luo, Ri Zan Li, Ning Ding, and Jiang Rong Xu. "Characteristic of Low Calorific Fuel Gas Combustion in Porous Burner by Preheating Air." Applied Mechanics and Materials 624 (August 2014): 361–65. http://dx.doi.org/10.4028/www.scientific.net/amm.624.361.

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The combustion characteristic of low calorific fuel gas was numerically investigated in porous burner by preheating air. Two-dimensional temperature profile, flame propagation precess, and CO reaction rate were analyzed detailly by preheating air, and compared with that of room air. The results showed that when the air is preheated, the combustion flame location locates to upstream, the maximum combustion temperature is higher than that of room air, and flame propagation velocity decreases.The CO oxidation reaction rate increases gradually with the radius distance increaing, but reaction region decreases. CO oxidation region guradually decreases and locates to the upstream with air preheating temperature increasing. Peaks of CO oxidation rate gradually change from two to one.

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Lalovic, Milisav, Zarko Radovic, and Nada Jaukovic. "Characteristics of heat flow in recuperative heat exchangers." Chemical Industry 59, no. 9-10 (2005): 270–74. http://dx.doi.org/10.2298/hemind0510270l.

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A simplified model of heat flow in cross-flow tube recuperative heat exchangers (recuperators) was presented in this paper. One of the purposes of this investigation was to analyze changes in the values of some parameters of heat transfer in recuperators during combustion air preheating. The logarithmic mean temperature (Atm) and overall heat transfer coefficient (U), are two basic parameters of heat flow, while the total heated area surface (A) is assumed to be constant. The results, presented as graphs and in the form of mathematical expressions, were obtained by analytical methods and using experimental data. The conditions of gaseous fuel combustions were defined by the heat value of gaseous fuel Qd = 9263.894 J.m-3, excess air ratio ?= 1.10, content of oxygen in combustion air ?(O2) = 26%Vol, the preheating temperature of combustion air (cold fluid outlet temperature) tco = 100-500?C, the inlet temperature of combustion products (hot fluid inlet temperature) thi = 600-1100?C.

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Mollica, Enrico, Eugenio Giacomazzi, and Marco di. "Numerical study of hydrogen mild combustion." Thermal Science 13, no. 3 (2009): 59–67. http://dx.doi.org/10.2298/tsci0903059m.

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In this article a combustor burning hydrogen and air in mild regime is numerically studied by means of computational fluid dynamic simulations. All the numerical results show a good agreement with experimental data. It is seen that the flow configuration is characterized by strong exhaust gas recirculation with high air preheating temperature. As a consequence, the reaction zone is found to be characteristically broad and the temperature and concentrations fields are sufficiently homogeneous and uniform, leading to a strong abatement of nitric oxide emissions. It is also observed that the reduction of thermal gradients is achieved mainly through the extension of combustion in the whole volume of the combustion chamber, so that a flame front no longer exists ('flameless oxidation'). The effect of preheating, further dilution provided by inner recirculation and of radiation model for the present hydrogen/air mild burner are analyzed.

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Filkoski, Risto, Ilija Petrovski, and Zlatko Gjurchinovski. "Energy optimisation of vertical shaft kiln operation in the process of dolomite calcination." Thermal Science 22, no. 5 (2018): 2123–35. http://dx.doi.org/10.2298/tsci180125278f.

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The essential part of the refractory materials production on a basis of sintered dolomite as raw material is the process of dolomite calcination. The technology process usually takes place in shaft or rotary kilns, where the dolomite stone, CaMg(CO3)2, is subjected to a high temperature heat treatment. The calcination of the dolomite is highly endothermic reaction, requiring significant amount of thermal energy to produce sintered dolomite (CaO, MgO), generating a large flow of hot gases at the furnace outlet. The objective of this work was to assess the possibilities of utilization of waste heat of exhaust gases from a shaft kiln in order to improve the overall energy efficiency of the technology process. Several different options were analyzed: (a) preheating of a raw material, (b) preheating of heavy fuel oil, (c) preheating of combustion air, (d) preheating of combustion air and raw material with flue gas, and (e) preheating of air for combustion and for drying of a raw material. Option (e) was selected as the most attractive and therefore it was analyzed in more details, showing significant annual energy savings and relatively short simple payback period on the investment.

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Castro, Zamir Sánchez, Hugo Reinel García Bernal, and Oscar Andrés Mendieta Menjura. "Efecto del precalentamiento del aire primario y la humedad del bagazo de caña de azúcar durante la combustión en lecho fijo." Corpoica Ciencia y Tecnología Agropecuaria 14, no. 1 (May 24, 2013): 5. http://dx.doi.org/10.21930/rcta.vol14_num1_art:263.

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Los hornos utilizados para la elaboración de panela presentan pérdidas energéticas debido a una combustión incompleta del bagazo de caña de azúcar y al calor sensible en los gases de chimenea. Durante el proceso de producción de panela, el bagazo de caña de azúcar se utiliza como combustible, con fracciones másicas de humedad entre 30% y 50%, las cuales afectan el rendimiento de la combustión de una biomasa en lecho fijo. Gracias a que el precalentamiento del aire disminuye el tiempo de secado, su implementación en muchos sistemas de combustión de biomasa ha incrementado la eficiencia del proceso. Por tanto, en la presente investigación se estudió la influencia del contenido de humedad y el precalentamiento del aire primario sobre la temperatura, la composición del gas y la tasa de combustión, mediante un diseño experimental factorial mixto 3x2. Los resultados demostraron que el aumento en la humedad del bagazo de caña reduce la tasa de combustión y la conversión de carbono a CO2, y por tanto, el rendimiento del proceso. Cuando se precalentó el aire primario hasta una temperatura de 120 ºC, la tasa de combustión aumentó, sin embargo sólo significó un incremento en el rendimiento de la combustión para una fracción másica de humedad de 30%.Effect of primary air preheating and moisture sugarcane bagasse during fixed bed combustionFurnaces used to making jaggery have energy losses due to incomplete combustion of sugarcane bagasse and sensible heat in the flue gases. During jaggery production process, sugarcane bagasse is used as fuel, with mass fractions of humidity between 30% and 50%, which affect the combustion efficiency of a biomass in a fixed bed. Because the air preheating decreases the drying time, its implementation in many biomass combustion systems increases process efficiency. Therefore, in this investigation we studied the influence of the moisture content and the preheating of the primary air on the combustion of bagasse in a fixed bed furnace, by analyzing the profiles of temperature and concentration of the combustion gas. Results showed that increasing in bagasse moisture reduces the rate of combustion and conversion of carbon to CO2, diminishing the yield of process. When the primary air is preheated to a temperature of 120 ºC, the combustion rate increased, however, only meant an increase in combustion efficiency to a mass fraction of 30% humidity.

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Cui, Yun Jing, and Qi Zhao Lin. "Realization of Flameless Combustion of Liquid Fuel." Advanced Materials Research 512-515 (May 2012): 2088–92. http://dx.doi.org/10.4028/www.scientific.net/amr.512-515.2088.

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Being an advantageous combustion technology, flameless combustion is being widely investigated mainly with gaseous fuels for its high efficiency and low pollution. In this paper the realization of liquid flameless combustion in micro turbine environment is investigated. It is indicated that air preheating is not the essential condition to attain flameless mode and the air injection speed is more important to lower the whole reaction rate. Flameless combustion was described in terms of the realization mechanism, flow field, flame shape, temperature, and emissions. Finally the heat transfer model of the recirculated gas applicable to liquid fuel flameless combustion based on the combustor structure is presented.

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Cui, Zhen Min. "Study on Temperature Distribution of a Honeycomb Regenerator during Preheating Process." Applied Mechanics and Materials 170-173 (May 2012): 2699–702. http://dx.doi.org/10.4028/www.scientific.net/amm.170-173.2699.

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The HiTAC technology (High Temperature Air Combustion) is a reliable, industry proven combustion method. A three-dimensional numerical model is established which is for unsteady preheating process in honeycomb regenerator. The preheating period of honeycomb was simulated by means of computational fluid dynamics (CFD) software; the outlet temperature, temperature at lengthways of gas, and temperature at lengthways of honeycomb were obtained.

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Mohanasundaram, Kavin, and Nagarajan Govindan. "Effect of air preheating, exhaust gas recirculation and hydrogen enrichment on biodiesel/methane dual fuel engine." Thermal Science, no. 00 (2020): 146. http://dx.doi.org/10.2298/tsci191024146m.

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An experimental study was carried out to investigate the effect of intake air preheating, exhaust gas recirculation and hydrogen enrichment on performance, combustion and emission characteristics of Methane/waste cooking oil biodiesel fuelled compression ignition engine in dual fuel mode. Methyl ester derived from waste cooking oil was used as a pilot fuel which was directly injected into the combustion chamber at the end of the compression stroke. Methane/hydrogen-enriched methane was injected as the main fuel in the intake port during the suction stroke using a low pressure electronic port fuel injector which is controlled by an electronic control unit. The experiments were conducted at a constant speed and at the maximum load. Experimental results indicated that the increase in energy share of gaseous fuel extends the ignition delay. With air preheating the thermal efficiency increased to 49% and 55% of methane and hydrogen-enriched methane energy share respectively. Carbon monoxide and hydrocarbon emissions were higher in methane combustion with biodiesel when compared to the conventional diesel operation at full load and a reduction in carbon monoxide and hydrocarbon was observed with air preheating. Lower oxides of nitrogen were observed with gaseous fuel combustion and it further reduced with exhaust gas recirculation but oxides of nitrogen increased by preheating the intake air. Improvement in thermal efficiency with a reduction in hydrocarbon and carbon monoxide was observed with hydrogen-enriched methane.

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Newburn, E. Ryan, and Ajay K. Agrawal. "Liquid Fuel Combustion Using Heat Recirculation Through Annular Porous Media." Journal of Engineering for Gas Turbines and Power 129, no. 4 (January 21, 2007): 914–19. http://dx.doi.org/10.1115/1.2719259.

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A counter-flow annular heat recirculating burner was designed for lean prevaporized, premixed combustion. Prior to entering the combustor, the reactants are passed through a porous media-filled preheating annulus surrounding the combustor. Kerosene is dripped by gravity onto the porous media and vaporized by the heat conducted through the combustor wall. Experiments were conducted to evaluate heat transfer and combustion performance at various equivalence ratios, heat release rates, and inlet air temperatures. Results show low CO emissions over a range of equivalence ratios. NOx emissions were high at high heat release rates, indicating inadequate prevaporization and premixing of fuel with air. Heat recirculation and heat loss characteristics are presented at various operating conditions.

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Hubbard, M., D. K. Krehbiel, and S. R. Gollahalli. "A Laboratory-Scale Experimental Study of In-Situ Combustion Processes." Journal of Energy Resources Technology 116, no. 3 (September 1, 1994): 169–74. http://dx.doi.org/10.1115/1.2906439.

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A laboratory-scale experimental study of in-situ combustion for enhanced oil recovery is presented. The effects of oil saturation, preheating of the oil-sand bed, porosity of sand, and air-injection rate on both the time history of liquid yield and the total liquid yield have been determined. From the measured temperature profiles and charred length of oil-sand bed, the propagation rate of combustion front has been deduced. The volumetric concentrations of CO2 and O2 in the effluent gas have been measured. The rate of liquid yield is highest in the initial periods of insitu heating or combustion. Air-injection rate, although it has an indirect influence on the temperatures achieved in the bed, exerts only a weak effect on the liquid yield. The increase in porosity of sand increases the liquid yield rate. The relative effects of air injection rate, oil saturation, and the porosity of sand under combustion conditions are simulated well by preheating the bed.

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Ishiguro, T., A. Matsunami, K. Matsumoto, K. Kitagawa, N. Arai, and A. K. Gupta. "Mass Spectrometric Detection of Ionic and Neutral Species During Highly Preheated Air Combustion by Alkali Element Ion Attachment." Journal of Engineering for Gas Turbines and Power 124, no. 4 (September 24, 2002): 749–56. http://dx.doi.org/10.1115/1.1473158.

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The use of high temperature and low oxygen concentration air as the oxidizer for regenerative combustion has become of increasing interest because this technology results in higher thermal efficiency, low energy consumption, and reduced emission of pollutants, such as NOx and CO2, and compact size of the equipment. In this study information is provided on the effect of preheating the low oxygen concentration air on the formation and detection of chemical ions and neutral species formed in flames. These ions and species were detected directly using mass spectrometry. Such information also assists in determining the combustion mechanism. The intact ionic species have been detected only at downstream position of the flames. By applying an alkali element Li+ ion attachment technique, neutral species, such as Li+-attached ions have been also detected successfully. Three specific flame cases have been examined. They include using normal air (flame I), preheated air (flame II), and preheated air with low (diluted) oxygen concentration in air (flame III). The results show significant change in the spectra of the intact ionic species and the Li+-adduct neutral species amongst the three flames. The results also show that preheating the combustion air increases the number of chemical species formed in the flames. However, these chemical species decrease with low oxygen concentration (diluted) combustion air.

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Du, Tao, Li Sheng Ji, and Guang Yi Gao. "Numerical Simulation of Furnace Combustion Characteristic in HTAC." Applied Mechanics and Materials 84-85 (August 2011): 274–78. http://dx.doi.org/10.4028/www.scientific.net/amm.84-85.274.

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In this thesis, in the double preheating system of air and gas, the high temperature air combustion process of low calorific value gas, in which the FLUENT software is used as the calculating tool and furnace model as the object, is numerically simulated by use of the k-ε turbulent two-way model, the PDF combustion model, discrete-ordinates-method radiative heat transfer model and the modified NOX -generation thermal model. Get the flow field, temperature field and concentration field inside the furnace in different times.

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Attia, Mohammed El Hadi. "Effect of the Preheating Inlet Air on the G222 Fuel Combustion." International Journal of Energetica 3, no. 2 (January 2, 2019): 29. http://dx.doi.org/10.47238/ijeca.v3i2.75.

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In this paper, a numerical simulation is developed to study the preheating effect of the air in a three-dimensional cylindrical combustion chamber using the FLUENT-CFD code. Particularly, we are interested on the calculation of the characteristic parameters such as the axial velocity, the temperature and the mass fraction of carbon monoxide. This study consists of a special treatment of mathematical models. The considered approaches resolve the governing equations of system. The main objective of this work is to study the behavior of the parameters considered previously during the variation of the air inlet temperature. The obtained results show that the variation of the inlet temperature presents a direct effect on the considered parameters.

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Khaleghi, Mostafa, S. E. Hosseini, M. A. Wahid, and H. A. Mohammed. "The Effects of Air Preheating and Fuel/Air Inlet Diameter on the Characteristics of Vortex Flame." Journal of Energy 2015 (2015): 1–10. http://dx.doi.org/10.1155/2015/397219.

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The effects of fuel/air inlet diameter as well as air preheating on the flame stability, temperature distribution, pollutant formation, and combustion characteristics of a lab-scaled asymmetric vortex flame have been investigated. A three-dimensional steady-state finite volume solver has been used to solve the governing and energy equations. The solver uses a first-order upwind scheme to discretize the governing equations in the space. The semi-implicit method for pressure linked equations has been applied to couple the pressure to the velocity terms. Several turbulence models were applied to predict the flame temperature and it was found thatk-εRNG has given the best results in accordance with the experimental results. The results reveal that the inlet air diameter can enhance the thermal properties and reduce theNOxemission while the inlet fuel diameter has less significant impact. Increasing diameters are accompanied with a pressure drop. It was found that preheating the air and fuel would significantly affect the flame temperature andNOxemission with constant mass flow rate.

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Kalinchak, V. V., A. S. Chernenko, A. N. Sofronkov, and A. V. Fedorenko. "Ignition and Self-Supporting Burning of Gas-Air Mixtures with Hydrogen Admixtures on Platinum Wire." Фізика і хімія твердого тіла 18, no. 4 (December 27, 2017): 449–54. http://dx.doi.org/10.15330/pcss.18.4.454.

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The proposed work describes analytical identification of hydrogen admixture concentration and catalyst temperatures limit values beyond which catalytic flameless steady combustion of gas-air mixtures at ambient temperature at platinum wires is observed. The effect of gas-air slip velocity upon considered values is shown. Initial platinum wire preheating temperatures required for catalytic ignition are determined.

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F., S. R. Khatami, B. Safavisohi, and E. Sharbati. "Porosity and Permeability Effects on Centerline Temperature Distributions, Peak Flame Temperature, Flame Structure, and Preheating Mechanism for Combustion in Porous Media." Journal of Energy Resources Technology 129, no. 1 (March 26, 2006): 54–65. http://dx.doi.org/10.1115/1.2424964.

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The applicability and usefulness of combustion in porous media is of much interest due to its competitive combustion efficiency and lower pollutants formation. In the previous works, the focus has been on the effects of combustion and heat transfer parameters such as excess air ratio, thermal power, solid conductivity, convective heat transfer coefficient, and radiation properties on centerline temperature and pollutant formations. A premixed combustion scheme and a fixed porous medium with constant geometrical parameters have been used in these works; therefore, the effects of porous material parameters have been less considered. In this research, the effects of geometrical parameters of porous medium, namely porosity and permeability, on centerline temperature distributions, peak flame temperature, flame structure, and gas mixture preheating have been investigated by numerical methods. To this, a two-dimensional axis-symmetric physical model of porous burner is considered. As the most typical porous burners, a two stage one which has preheating porous zone (PPZ) and combustion porous zone (CPZ) is studied. The continuity, momentum, energy, turbulence, and species transport equations are solved employing a one-step chemical reaction mechanism with an eddy-dissipation model for rate of reactions. The turbulence is modeled with two transport equations which are not considered in similar works. The combustion regime is assumed to be diffusion and combustion parameters are fixed in all cases. Porosity effects on the structure and temperature characteristic of the flame are probed in a wide range for PPZ and CPZ. Critical permeability is defined and permeability effects on flame characters in both of the preheating and combustion regions are studied thoroughly.

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Saeed, M. N., and N. A. Henein. "Combustion Phenomena of Alcohols in C. I. Engines." Journal of Engineering for Gas Turbines and Power 111, no. 3 (July 1, 1989): 439–44. http://dx.doi.org/10.1115/1.3240273.

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A study was conducted on a direct-injection, single-cylinder, research-type diesel engine to determine the effect of adding ethanol or isopropanol to diesel fuel on the ignition delay period. The test parameters were alcohol content, intake-air properties, and fuel-air ratio. It was found that the ignition delay of alcohol-diesel blends is prolonged as the alcohol content is increased. Ethanol-diesel blends developed longer ignition delays than those developed by isopropanol-diesel blends. The results showed that ignition delay of alcohol-diesel blends can be effectively shortened using intake-air preheating and/or supercharging. The high activation energy of alcohols with respect to diesel fuel is believed to be responsible for the long ignition delays associated with the use of alcohols as alternate fuels in compression ignition engines.

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Karamarkovic, Rade, Vladan Karamarkovic, Aleksandar Jovovic, Miljan Marasevic, and Andjela Lazarevic. "Biomass gasification with preheated air: Energy and exergy analysis." Thermal Science 16, no. 2 (2012): 535–50. http://dx.doi.org/10.2298/tsci110708011k.

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Due to the irreversibilities that occur during biomass gasification, gasifiers are usually the least efficient units in the systems for production of heat, electricity, or other biofuels. Internal thermal energy exchange is responsible for a part of these irreversibilities and can be reduced by the use of preheated air as a gasifying medium. The focus of the paper is biomass gasification in the whole range of gasification temperatures by the use of air preheated with product gas sensible heat. The energetic and exergetic analyses are carried with a typical ash-free biomass feed represented by CH1.4O0.59N0.0017 at 1 and 10 bar pressure. The tool for the analyses is already validated model extended with a heat exchanger model. For every 200 K of air preheating, the average decrease of the amount of air required for complete biomass gasification is 1.3% of the amount required for its stoichiometric combustion. The air preheated to the gasification temperature on the average increases the lower heating value of the product gas by 13.6%, as well as energetic and exergetic efficiencies of the process. The optimal air preheating temperature is the one that causes gasification to take place at the point where all carbon is consumed. It exists only if the amount of preheated air is less than the amount of air at ambient temperature required for complete gasification at a given pressure. Exergy losses in the heat exchanger, where the product gas preheats air could be reduced by two-stage preheating.

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Yang, J. T., and G. G. Wang. "The Effect of Heat Transfer on Coal Devolatilization." Journal of Heat Transfer 112, no. 1 (February 1, 1990): 192–200. http://dx.doi.org/10.1115/1.2910344.

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This study investigates the heat transfer effect on the transient behavior of preheating, ignition, and combustion of a single coal particle pyrolyzed in a hot convective environment. The theoretical model covers two aspects: (1) heat and mass transfer and pyrolysis within the particle, (2) thermal radiation, diffusion, and combustion of the reactive gases and air outside of the particle. Semenov’s criteria are adopted to define ignition and a modified model derived from droplet combustion is used to estimate the flame radius and temperature. Distributions of temperature, species concentrations, and combustion rate are solved simultaneously. The prediction is verified by a set of experimental data.

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Mardani, Amir, Rezapour Rastaaghi, and Fazlollahi Ghomshi. "Liquid petroleum gas flame in a double-swirl gas turbine model combustor: Lean blow-out, pollutant, preheating." Thermal Science, no. 00 (2020): 139. http://dx.doi.org/10.2298/tsci190623139m.

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In this paper, lean blow-out (LBO) limits in a double swirl gas turbine model combustor were investigated experimentally for Liquid Petroleum Gas (LPG) fuel. The LBO curve was extracted for different combustor configurations. While burner could operate reasonably under ultra-lean conditions, two different sets of operating conditions, one with a low flow rate (LFR) and another one with high flow rate (HFR), are identified and studied in terms of LBO and pollutant. Results showed that while the flame structure was similar in both cases, the chamber responses to geometrical changes and also preheating are minimal at the LFR. That means confinement and injector type have desirable effects on stability borders but not for the LFR. The channeled injector shifted down the LBO limit around 28 percent at HFR. Measurements on the combustor exhaust gas composition and temperature indicate a region with relatively complete combustion and reasonable temperature and a very low level of exhaust NOx pollutants (i.e., below ten ppm) at about 25-50% above the LBO. In this operating envelope, a burner power increment led to a higher exhaust average temperature and combustion efficiency, while NOx formation decreased. Preheating the inlet air up to 100?C results in an improvement in burner stability in about 10 percent, but NOx production intensifies more than three times. Results indicate that the LBO limit is configured more by the burner design and aerodynamic aspects rather than the fuel type.

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Gaba, Aurel, Vasile Bratu, Dorian Musat, Ileana Nicoleta Popescu, and Maria Cristiana Enescu. "Analysis of the Combustion Air Preheater from the Aluminum Melting Furnaces." Scientific Bulletin of Valahia University - Materials and Mechanics 14, no. 11 (October 1, 2016): 27–32. http://dx.doi.org/10.1515/bsmm-2016-0005.

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Abstract This paper presents solutions and the equipment for preheating combustion air from scrap aluminum melting furnaces through flue gas heat recovery. For sizing convection pre-heaters, there has been developed a mathematical model which has been transcribed into a computer program in C + +. A constructive version of the pre-heater was drawn up and a recovery heat exchanger was manufactured and mounted on an aluminum melting furnace. Both the functional parameters values and the reasons causing the pre-heater worning out, as well as the steps taken for sizing and the achievement of a new air pre-heater able to bear the operating conditions of the aluminum melting furnace are shown.

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Milanese, Marco, Marco Torresi, Gianpiero Colangelo, Alessandro Saponaro, and Arturo de Risi. "Numerical Analysis of a Solar Air Preheating Coal Combustion System for Power Generation." Journal of Energy Engineering 144, no. 4 (August 2018): 04018038. http://dx.doi.org/10.1061/(asce)ey.1943-7897.0000553.

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Shinohara, Koichi, Daisuke Kono, Masayoshi Minakami, Tatsuya Kawajiri, Shuji Hironaka, and Jun Fukai. "Contribution of Combustion Air Preheating to Operation of an Industrial Waste Treatment Plant." KAGAKU KOGAKU RONBUNSHU 47, no. 2 (March 20, 2021): 36–43. http://dx.doi.org/10.1252/kakoronbunshu.47.36.

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Cepic, Zoran, and Branka Nakomcic-Smaragdakis. "Experimental analysis of the influence of air-flow rate on wheat straw combustion in a fixed bed." Thermal Science 21, no. 3 (2017): 1443–52. http://dx.doi.org/10.2298/tsci160403261c.

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Biomass in the form of crop residues represents a significant energy source in regions whose development is based on agricultural production. Among many possibilities of utilizing biomass for energy generation, combustion is the most common. With the aim of improving and optimizing the combustion process of crop residues, an experimental rig for straw combustion in a fixed bed was constructed. This paper gives a brief review of working characteristics of the experimental rig, as well as the results for three different measuring regimes, with the purpose to investigate the effect of air-flow rate on the wheat straw combustion in a fixed bed. For all three regimes analysed in this paper bulk density of the bed was the same, 60 kg/m3, combustion air was without preheating and air-flow rates were: 1152, 1872, and 2124 kg/m2h. The effect of air-flow rate on the ignition rate, burning rate, temperature profile of the bed and flue gas composition were analysed. It was concluded that in the regime with the lowest air-flow rate progress of combustion had two clearly conspicuous stages: the ignition propagation stage and the char and unburned material oxidation stage. At the highest air-flow rate the entire combustion occurred mostly in a single stage, due to increased air supply oxidized the char, remaining above the ignition front, simultaneously with the reactions of volatiles. Despite that, the optimal combustion process, the highest value of ignition rate, burning rate, and bed temperature was achieved with air-flow rate of 1872 kg/m2h.

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Каlіnchak, V. V., O. S. Chernenko, and A. V. Fedorenko. "Electric resistence hysteresis of platinum filament in chilled air/hydrogen mixtures." Physics and Chemistry of Solid State 21, no. 3 (September 30, 2020): 420–25. http://dx.doi.org/10.15330/pcss.21.3.420-425.

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Ignition of gaseous combustible mixtures on catalytically active hot solid surfaces has numerous applications in many industrial processes and is a complex process that involves close interaction between surface processes and transfer processes in the gas mixture. In this paper, stable and critical states catalytic oxidation of hydrogen impurities in air on a platinum filament are considered. It is shown that filament temperature and its resistance depending on the mixture temperature and hydrogen concentration are of the hysteresis features. Within this hysteresis region, it is possible to achieve the catalytic combustion mode of hydrogen as a result preheating the catalyst filament above a certain critical value. The dependence of the limiting hydrogen's concentration on catalyst filament's diameter, above which is observed in the cold gas mixture self-sustaining catalytic combustion without electric current.

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Slefarski, Rafal, Pawel Czyzewski, and Michal Golebiewski. "Experimental study on combustion of CH4/NH3 fuel blends in an industrial furnace operated in flameless conditions." Thermal Science 24, no. 6 Part A (2020): 3625–35. http://dx.doi.org/10.2298/tsci200401282s.

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This paper presents the results of an experimental study on the combustion process of methane mixed with NH3 in flameless mode. At a time of striving for CO2-free power, NH3 became a potential energy storage carrier fuel from renewable sources. Flameless combustion features low emissions and is a very efficient technology used in the power sector, as well as steel production, ceramics, etc. Industrial furnaces were tested in the context of pure methane combustion with an addition of NH3, up to 5%. Flameless combustion conditions were achieved with a regenerative gas burner system (high regenerative system). The burner consists of four ceramic regenerators allowing for continuous preheating of air, even up to 50 K lower than the temperature of the combustion chamber wall. Constant power of the introduced fuel was kept at 150 kW and the fuel-air equivalence ratio ranged from 0.75 to 0.95. The results have shown a growth of molar fraction of NO in flue gases when NH3 content in the fuel rose. The increase is more significant for the tests with a higher amount of oxygen in the combustion chamber (a lower fuel-air equivalence ratio). An addition of 5% of NH3 into the fuel caused an emission of NO at the levels of 113 ppmv and 462 ppmv (calculated to O2 = 0%), respectively for low and high fuel-air equivalence ratios.

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Tu, Yaojie, Kai Su, Hao Liu, Zean Wang, Yihao Xie, Chuguang Zheng, and Weijie Li. "MILD combustion of natural gas using low preheating temperature air in an industrial furnace." Fuel Processing Technology 156 (February 2017): 72–81. http://dx.doi.org/10.1016/j.fuproc.2016.10.024.

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van Kessel, L. B. M., A. R. J. Arendsen, P. D. M. de Boer-Meulman, and G. Brem. "The effect of air preheating on the combustion of solid fuels on a grate." Fuel 83, no. 9 (June 2004): 1123–31. http://dx.doi.org/10.1016/j.fuel.2003.11.008.

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McNally, Dylan, Marika Agnello, Brigitte Pastore, James R. Applegate, Eric Westphal, and Smitesh D. Bakrania. "A Study of Fuel and Reactor Design for Platinum Nanoparticle Catalyzed Microreactors." Journal of Nanomaterials 2015 (2015): 1–8. http://dx.doi.org/10.1155/2015/538752.

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Typical microcombustion-based power devices entail the use of catalyst to sustain combustion in less than millimeter scale channels. This work explores the use of several other candidate fuels for ~8 nm diameter Pt particle catalyzed combustion within 800 μm channel width cordierite substrates. The results demonstrate while commercial hydrocarbon fuels such as methane, propane, butane, and ethanol can be used to sustain catalytic combustion, room temperature ignition was only observed using methanol-air mixtures. Fuels, other than methanol, required preheating at temperatures >200°C, yet repeated catalytic cycling similar to methanol-air mixtures was demonstrated. Subsequently, a new reactor design was investigated to couple with thermoelectric generators. The modified reactor design enabled ignition of methanol-air mixtures at room temperature with the ability to achieve repeat catalytic cycles. Preliminary performance studies achieved a maximum temperature differenceΔTof 55°C with a flow rate of 800 mL/min. While the temperature difference indicates a respectable potential for power generation, reduced exhaust temperature and improved thermal management could significantly enhance the eventual device performance.

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Griebel, P., E. Boschek, and P. Jansohn. "Lean Blowout Limits and NOx Emissions of Turbulent, Lean Premixed, Hydrogen-Enriched Methane/Air Flames at High Pressure." Journal of Engineering for Gas Turbines and Power 129, no. 2 (August 15, 2006): 404–10. http://dx.doi.org/10.1115/1.2436568.

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Flame stability is a crucial issue in low NOx combustion systems operating at extremely lean conditions. Hydrogen enrichment seems to be a promising option to extend lean blowout limits (LBO) of natural gas combustion. This experimental study addresses flame stability enhancement and NOx reduction in turbulent, high-pressure, lean premixed methane/air flames in a generic combustor capable of a wide range of operating conditions. Lean blowout limits and NOx emissions are presented for pressures up to 14bar, bulk velocities in the range of 32–80m∕s, two different preheating temperatures (673K, 773K), and a range of fuel mixtures from pure methane to 20% H2∕80%CH4 by volume. The influence of turbulence on LBO limits is also discussed. In addition to the investigation of perfectly premixed H2-enriched flames, LBO and NOx are also discussed for hydrogen piloting. Experiments have revealed that a mixture of 20% hydrogen and 80% methane, by volume, can typically extend the lean blowout limit by ∼10% compared to pure methane. The flame temperature at LBO is ∼60K lower resulting in the reduction of NOx concentration by ≈35%(0.5→0.3ppm∕15%O2).

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Jia, Zhenzhen, Qing Ye, Haizhen Wang, He Li, and Shiliang Shi. "Numerical Simulation of a New Porous Medium Burner with Two Sections and Double Decks." Processes 6, no. 10 (October 6, 2018): 185. http://dx.doi.org/10.3390/pr6100185.

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Porous medium burners are characterized by high efficiency and good stability. In this study, a new burner was proposed based on the combustion mechanism of the methane-air mixture in the porous medium and the preheating effect. The new burner is a two-section and double-deck porous medium with gas inlets at both ends. A mathematical model for the gas mixture combustion in the porous medium was established. The combustion performance of the burner was simulated under different equivalence ratios and inlet velocities of premixed gas. The methane combustion degree, as well as the temperature and pressure distribution, was estimated. In addition, the concentrations of emissions of NOx for different equivalence ratios were investigated. The results show that the new burner can not only realize sufficient combustion but also save energy. Furthermore, the emission concentration of NOx is very low. This study provides new insights into the industrial development and application of porous medium combustion devices.

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Ding, Cuijiao, Pengfei Li, Guodong Shi, Yaowei Liu, Feifei Wang, Fan Hu, Shixin Huang, and Zhaohui Liu. "Comparative Study between Flameless Combustion and Swirl Flame Combustion Using Low Preheating Temperature Air for Homogeneous Fuel NO Reduction." Energy & Fuels 35, no. 9 (April 15, 2021): 8181–93. http://dx.doi.org/10.1021/acs.energyfuels.0c04266.

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Matyukhin, V. I., S. G. Stakheev, A. V. Matyukhina, and S. Ya Zhuravlev. "Thermal Neutralization Of Excessive Heat Transfer Agent In Coke Dry-Quenching Plants (CDQP)." KnE Materials Science 2, no. 2 (September 3, 2017): 14. http://dx.doi.org/10.18502/kms.v2i2.940.

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The paper considers the problem of reducing emissions of harmful substances in the process of coke dry quenching. It proposes an option for thermal neutralization of excessive heat transfer agent in the coke dry-quenching plants as well as preheating of heat transfer agent and air by exhaust combustion products. The paper presents a process diagram and main process parameters of plant operation. It shows efficient recovery of secondary energy resources in the form of chemical heat in the proposed plant.

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Dellenback, Paul A. "A Reassessment of the Alternative Regeneration Cycle." Journal of Engineering for Gas Turbines and Power 128, no. 4 (August 19, 2005): 783–88. http://dx.doi.org/10.1115/1.2179079.

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Two prior papers and several patents have considered improvements to a gas turbine engine’s cycle efficiency by using two turbines in series with an intermediate heat exchanger that preheats combustion air. This approach allows heating the combustion air to temperatures higher than those that can be achieved with “conventional regeneration” in which the combustion products are fully expanded across a turbine before any heat recovery. Since heat addition in the combustor of the “alternative regeneration” cycle occurs at a higher average temperature, then under certain conditions the cycle efficiency can be higher than that available from a cycle using conventional regeneration. This paper reconsiders the usefulness of the alternative regeneration cycle with more detailed modeling than has been presented previously. The revised modeling shows that the alternative regeneration cycle can produce efficiencies higher than conventional regeneration, but only for a more limited set of conditions than previously reported. For high-technology engines operating at high temperatures, the alternative regeneration cycle efficiencies can be three to four percentage points better than comparable conventional regeneration cycles. For lower-technology engines, which are more typical of those currently installed, improvements in efficiency only occur at lower values of heat exchanger effectiveness, which limits the usefulness of the alternative regeneration cycle. Also considered is an extension to the cycle that employs a second heat exchanger downstream of the second turbine for the purpose of further preheating the combustion air. In its optimum configuration, this “staged heat recovery” can produce additional small improvements of between 0.3 and 2.3 percentage points in cycle efficiency, depending on the particular cycle parameters assumed.

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Bhaskaran Anangapal, Hari. "Energy and exergy analysis of fuels." International Journal of Energy Sector Management 8, no. 3 (August 26, 2014): 330–40. http://dx.doi.org/10.1108/ijesm-04-2013-0012.

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Purpose – The purpose of this study is to carry out energy and exergy analysis of fuels. Production of power and heat in industrialized countries is almost entirely based on combustion of fuels. Usually, combustion takes place in boilers or furnace; well-designed boilers have high thermal efficiencies of > 90 per cent. Even very high efficiencies, close to 100 per cent can be achieved depending on the applied fuel and boiler type. These high thermal efficiencies do suggest that combustion processes are highly optimized and do not need further improvements with regard to their thermodynamic performance. Second law (entropy or exergy) evaluations, however, shows that thermodynamic losses of boiler and furnaces are much larger than the thermal efficiencies do suggest. During combustion, air is predominantly used. When using air, the adiabatic combustion temperature depends only on the properties of fuel and air. The determining parameters for optimal fuel utilization are the fuel type, their composition and moisture content, the air temperature and air factor at combustion inlet. Design/methodology/approach – Following assumptions are made for the analysis: calculation on the basis of 100 kg of dry and ash free fuel entering the control volume; fuel entering the control volume at T0, P0 and reacting completely with air entering separately at T0, P0 to form CO2, SO2, N2 and H2O, which exit separately at T0, P0 (T0 = 298 K; P0 = 1 atm); all heat transfer occurs at temperature T0; and the chemical exergy of the ash has been ignored The availability change and the irreversibility for chemical reactions of hydrocarbon fuels were studied because fuel and dry air composed of O2 and N2 react to form products of combustion in the restricted dead state, and fuel and dry air composed of O2 and N2 react to form products of combustion which end up in the environmental (unrestricted) dead state. The difference between the above two statement, is the chemical availability of the product gases as they proceed from the restricted to the unrestricted dead state. These evaluations were made in terms of enthalpy and entropy values of the reacting species. T0 extend these concepts to the most general situation, it is considered a steady-state control volume where the fuels enters at the restricted dead state, the air (oxidant) is drawn from the environment, and the products are returned to the unrestricted dead state. Findings – It is evident from the analysis that an air factor of 1.10-1.20 is sufficient for liquid fuels, whereas solid fuels will require air factors of 1.15–1.3. When the temperatures of the products of combustion (Tp) are cooled down to that of T0, the maximum reversible work occurs. From the analysis, it is clear that the rather low combustion temperature and the need for cooling down the flue gases to extract the required heat are the main causes of the large exergy losses. The maximum second law efficiency also occurs when Tp is set equal to T0. The maximum second law efficiency per kilo mole of fuel is found to be 73 per cent, i.e. 73 per cent of the energy released by the cooling process could theoretically be converted into useful work. It is evident that reducing exergy losses of combustion is only useful if the heat transferred from the flue gas is used at high temperatures. Otherwise, a reduction of exergy loss of combustion will only increase the exergy loss of heat transfer to the power cycle or heat-absorbing process. The exergy loss of combustion can be reduced considerable by preheating combustion air. Higher preheat temperatures can be obtained by using the flue gas flow only for preheating air. The remainder of the flue gas flow can be used for heat transfer to a power cycle or heat-absorbing process. Even with very high air preheat temperatures, exergy losses of combustion are still > 20 per cent. The application of electrochemical conversion of fuel, as is realized in fuel cells, allows for much lower exergy loses for the reaction between fuel and air than thermal conversion. For industrial applications, electrochemical conversion is not yet available, but will be an interesting option for the future. Originality/value – The outcome of the study would certainly be an eye-opener for all the stakeholders in thermal power plants for considering the second law efficiency and to mitigate the irreversibilities.

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Costa, R. C., and M. A. Martins. "PROTOTYPE OF A HEAT RECOVERY FOR COOLING OF GASES FROM INCINERATION OF HAZARDOUS WASTE." Revista de Engenharia Térmica 13, no. 1 (June 30, 2014): 80. http://dx.doi.org/10.5380/reterm.v13i1.62074.

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This paper presents the stages of development and construction of a prototype of a shell and tube heat recovery for reuse heat energy of the products generated by combustion of hazardous waste incinerator class I. The performance and energy recovered by this system were calculated. It was transported the values found for a typical plant for the incineration of 1,000 kg h-1. Thus, to preheat the combustion air and drying the waste was obtained a reduction in the consumption of LPG 46 and 45%, respectively. Considering the complexity of the process, it was found that the preheating system is simpler and can be deployed in a shorter time and lower cost when compared to a drying residue.

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FURUICHI, Shinji, Masatoshi TOYAMA, Hiroyasu SAITOH, Nozomu KANNO, and Norihiko YOSHIKAWA. "Lean Combustion Enhancement of Ethanol Vapor-Air Flames by Hydrogen Addition and Preheating(Thermal Engineering)." Transactions of the Japan Society of Mechanical Engineers Series B 76, no. 765 (2010): 924–29. http://dx.doi.org/10.1299/kikaib.76.765_924.

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Wang, Yang, Zhijun Zhou, Weijuan Yang, Junhu Zhou, Jianzhong Liu, and Kefa Cen. "The Impact of Preheating on Stability Limits of Premixed Hydrogen–Air Combustion in a Microcombustor." Heat Transfer Engineering 33, no. 7 (May 2012): 661–68. http://dx.doi.org/10.1080/01457632.2012.630274.

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Valenti, Michael. "Local Connections." Mechanical Engineering 122, no. 07 (July 1, 2000): 50–53. http://dx.doi.org/10.1115/1.2000-jul-1.

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This article discusses integration of microturbines with energy storage systems and fuel cells for the development of new applications in distributed energy generation. Williams Energy Services integrated two Capstone Model 330 microturbines and one PowerBlock energy storage system to power an oil derrick near the Denver airport. A key microturbine component is its recuperator, which transfers heat from exhaust gas to air that is sent to the combustor. Preheating combustion air reduces the fuel consumption of the microturbine and increases its overall efficiency. One hybrid microturbine power plant now in commercial service was developed by Williams Distributed Power Services of Tulsa, Oklahoma. The Williams energy conversion unit (ECU) incorporates two Model 330-kilowatt microturbines developed by Capstone Turbine Corp. of Woodland Hills, California, and the PowerBlock energy storage device developed by Powercell Corp. of Burlington, MA. The ECU provides reliable 480-volt power when the grid power to the oil field is interrupted.

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Fialko, N. M., G. A. Presich, G. A. Gnedash, S. I. Shevchuk, and I. L. Dashkovska. "INCREASE THE EFFICIENCY OF COMPLEX HEAT-RECOVERY SYSTEMS FOR HEATING AND HUMIDIFYING OF BLOWN AIR OF GAS-FIRED BOILERS." Industrial Heat Engineering 40, no. 3 (September 7, 2018): 38–45. http://dx.doi.org/10.31472/ihe.3.2018.06.

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The work is devoted to increase of thermal and ecological efficiency of water-heating gas-fired boilers of municipal heat-power engineering. To improve thermal efficiency, heat-recovery technologies are used in which deep cooling of the exhaust-gases from boilers with the realization of the condensation mode of the heat recovery equipment is ensured. To implement this regime throughout the heating period, it is advisable to use complex heat-recovery systems in which several heat transfer agents are heated with sufficiently different thermal potentials. To enhance the environmental effect when using complex systems, it is possible to carry out combustion air humidifying in them, which contributes to the reduction of NOx emissions to the environment by the boiler plants. The work suggests improvement of the known complex heat-recovery system for heating and humidifying the blown air by introducing into its comprise an additional element - water heater of chemical water-purification system. Such the technological solution will ensure a reduction in the thermal losses of the boiler plant and improve the operating conditions of the gas ducts of the boiler house by preventing the condensate from falling out of the wet exhaust-gases. The aim of the work is to investigate the operating parameters of the complex heat-recovery system for heating and humidifying the blown air and preheating the water for chemical water-purification and comparing its basic heatly and humidity characteristics with the corresponding complex system without preheating the water. The results of the investigations are presented in a wide operating range of the load variation of the water-heating boiler respectively the boiler plant temperature graph and are shown graphically. The analysis of the obtained data showed that due to the proposed modernization by preheating the water of the chemical water-purification system in the complex heat-recovery system for heating and humidifying the blown air, an increase of coefficient the use heat of fuel of boilers is provided, depending on their load from 11% to 17%. For this improved heat-recovery system with preheating the water of the chemical water-purification system in comparison with the system without such preheating, the total heating capacity of the complex system increases by 1.3÷1.6 times, and the coefficient the use heat of fuel of the boiler increases by 5.2%.

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Ramazanov, R., D. Suslov, L. Kuschev, A. Seminenko, and Valerij Uvarov. "THEORETICAL DESCRIPTION OF THE PROCESS OF HEATING THE GAS-AIR MIXTURE IN THE BODY OF THE BURNER WITH A THERMAL DIVIDER." Bulletin of Belgorod State Technological University named after. V. G. Shukhov 6, no. 8 (August 13, 2021): 26–34. http://dx.doi.org/10.34031/2071-7318-2021-6-8-26-34.

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The main thermal processes occurring during the operation of a gas burner device for household use are considered. One of the important functions performed by the gas burner device is the preparation of fuel for subsequent combustion. The efficiency and quality of the combustion process directly depends on the temperature of the gas-air mixture. Since an increase in the temperature of the mixture contributes to the intensification of the combustion process, when designing gas burner devices, it is useful to determine the temperature of the gas-air mixture inside the burner body. We have proposed a solution that makes it possible to increase the efficiency of the gas burner device by intensifying the preheating from the thermal divider to the gas-air mixture inside the body of the gas burner. It has been established that the placement of the thermal divider in the central part on the inner side of the cover allows one to reduce the stagnant zone area when the flow of the gas-air mixture moves, and the conical shape of the thermal divider provides minimal resistance to the movement of the gas-air mixture flow inside the gas burner, in addition, the side surface of the thermal divider additionally increases the area heat transfer. An expression is obtained for calculating the average temperature of the gas-air mixture at the outlet from the firing holes of the gas burner.

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42

Flamme, Michael, Christian Paul Beckervordersandforth, and Hans Kremer. "Effect of combustion air preheating on NOx emissions from gas burners in high-temperature industrial applications." Chemical Engineering & Technology - CET 11, no. 1 (1988): 104–12. http://dx.doi.org/10.1002/ceat.270110115.

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Yan, Mi, Antoni, Jingyi Wang, Dwi Hantoko, and Ekkachai Kanchanatip. "Numerical investigation of MSW combustion influenced by air preheating in a full-scale moving grate incinerator." Fuel 285 (February 2021): 119193. http://dx.doi.org/10.1016/j.fuel.2020.119193.

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Kumar, M. Senthil, A. Kerihuel, J. Bellettre, and M. Tazerout. "A Comparative Study of Different Methods of Using Animal Fat as a Fuel in a Compression Ignition Engine." Journal of Engineering for Gas Turbines and Power 128, no. 4 (October 17, 2005): 907–14. http://dx.doi.org/10.1115/1.2180278.

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This work explores a comparative study of different methods of using animal fat as a fuel in a compression ignition engine. A single-cylinder air-cooled, direct-injection diesel engine is used to test the fuels at 100% and 60% of the maximum engine power output conditions. Initially, animal fat is tested as fuel at normal temperature. Then, it is preheated to 70°C and used as fuel. Finally, animal fat is converted into methanol and ethanol emulsions using water and tested as fuel. A drop in cylinder peak pressure, longer ignition delay, and a lower premixed combustion rate are observed with neat animal fat as compared to neat diesel. With fat preheating and emulsions, there is an improvement in cylinder peak pressure and maximum rate of pressure rise. Ignition delay becomes longer with both the emulsions as compared to neat fats. However, preheating shows shorter ignition delay. Improvement in heat release rates is achieved with all the methods as compared to neat fats. At normal temperature, neat animal fat results in higher specific energy consumption and exhaust gas temperature as compared to neat diesel at both power outputs. Preheating and emulsions of animal fat show improvement in performance as compared to neat fat. Smoke is lower with neat fat as compared to neat diesel. It reduces further with all the methods. At peak power output, the smoke level is found as 0.89m−1 with methanol, 0.28m−1 with ethanol emulsions, and 1.7m−1 with fat preheating, whereas it is 3.7m−1 with neat fat and 6.3m−1 with neat diesel. Methanol and ethanol emulsions significantly reduce NO emissions due to the vaporization of water and alcohols. However, NO increases with fat preheating due to high in-cylinder temperature. Higher unburned hydrocarbon and carbon monoxide emissions are found with neat fat as compared to neat diesel at both power outputs. However, these emissions are considerably reduced with all the methods. It is finally concluded that adopting emulsification with the animal fat can lead to a reduction in emissions and an improvement in combustion characteristics of a diesel engine.

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Chen, Junjie, Baofang Liu, Xuhui Gao, and Deguang Xu. "Computational Fluid Dynamics Simulations of Lean Premixed Methane-Air Flame in a Micro-Channel Reactor Using Different Chemical Kinetics." International Journal of Chemical Reactor Engineering 14, no. 5 (October 1, 2016): 1003–15. http://dx.doi.org/10.1515/ijcre-2015-0174.

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Abstract Flame temperature and structure are a useful tool for describing flame dynamics and flame stability, especially at the micro-scale. The objective of this study is to examine the effect of different kinetic models (that have been proven to accurately predict the macro-combustion behavior of hydrocarbons) on the combustion characteristics and the flame stability in microreactors, and to explore the applicability of these kinetic models at the micro-scale. Computational fluid dynamics (CFD) simulations of lean premixed methane-air flame in micro-channel reactors were carried out to examine the effect of different reaction mechanisms (Mantel, Duterque and Fernández-Tarrazo model) on the reaction rate and the flame structure and temperature. The time-scales with regard to homogeneous reaction and heat transfer were analyzed. The CFD results indicate that kinetic models strongly affect flame stability. Large transverse gradients in temperature and species are observed in all kinetic models, despite the small scales of the microreactor. Preheating, combustion, and post-combustion regions can be distinguished only in Duterque and Mantel model. Duterque model causes a stable elongated homogeneous flame with a considerable ignition delay as well as a dead region with cold feed accumulation near the entrance, and is inappropriate for micro-combustion studies because of the seriously overestimated flame temperature. Fernández-Tarrazo model causes a rapid extinction and a flashback risk, and is also inappropriate for micro-combustion studies due to the significantly underestimated reaction rate, without taking all kinetic factors into account. Mantel model can accurately predict the micro-flame behavior and consequently can be used for describing micro-combustion.

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Wan, Jianlong, Yongjia Wu, and Haibo Zhao. "Excess enthalpy combustion of methane-air in a novel micro non-premixed combustor with a flame holder and preheating channels." Fuel 271 (July 2020): 117518. http://dx.doi.org/10.1016/j.fuel.2020.117518.

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Dolianitis, Ioannis, Dionysios Giannakopoulos, Christina-Stavrula Hatzilau, Sotirios Karellas, Emmanuil Kakaras, Evelina Nikolova, Georgios Skarpetis, Nikolaos Christodoulou, Nikolaos Giannoulas, and Theodoros Zitounis. "Waste heat recovery at the glass industry with the intervention of batch and cullet preheating." Thermal Science 20, no. 4 (2016): 1245–58. http://dx.doi.org/10.2298/tsci151127079d.

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A promising option to reduce the specific energy consumption and CO2 emissions at a conventional natural gas fired container glass furnace deals with the advanced utilization of the exhaust gases downstream the air regenerators by means of batch and cullet preheating. A 3-dimensional computational model that simulates this process using mass and heat transfer equations inside a preheater has been developed. A case study for an efficient small-sized container glass furnace is presented dealing with the investigation of the impact of different operating and design configurations on specific energy consumption, CO2 emissions, flue gas energy recovery, batch temperature and preheater efficiency. In specific, the effect of various parameters is studied, including the preheater?s dimensions, flue gas temperature, batch moisture content, glass pull, combustion air excess and cullet fraction. Expected energy savings margin is estimated to 12-15%.

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Askarova, Aysylu, Evgeny Popov, Matthew Ursenbach, Gordon Moore, Sudarshan Mehta, and Alexey Cheremisin. "Experimental Investigations of Forward and Reverse Combustion for Increasing Oil Recovery of a Real Oil Field." Energies 13, no. 17 (September 3, 2020): 4581. http://dx.doi.org/10.3390/en13174581.

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The work presented herein is devoted to a unique set of forward and reverse combustion tube (CT) experiments to access the suitability and potential of the in situ combustion (ISC) method for the light oil carbonate reservoir. One forward and one reverse combustion tube tests were carried out using the high-pressure combustion tube (HPCT) experimental setup. However, during reverse combustion, the front moved in the opposite direction to the airflow. The results obtained from experiments such as fuel/air requirements, H/C ratio, and recovery efficiency are crucial for further validation of the numerical model. A quantitative assessment of the potential for the combustion was carried out. The oil recovery of forward combustion was as high as 91.4% of the initial oil in place, while that for the reverse combustion test demonstrated a 43% recovery. In the given conditions, forward combustion demonstrated significantly higher efficiency. However, the stabilized combustion front propagation and produced gases of reverse combustion prove its possible applicability. Currently, there is a limited amount of available studies on reverse combustion and a lack of publications within the last decades despite advances in technologies. However, reverse combustion might have advantages over forward combustion for heavy oil reservoirs with lower permeability or might serve as a reservoir preheating technique. These experiments give the opportunity to build and validate the numerical models of forward and reverse combustion conducted at reservoir conditions and test their field application using different scenarios.

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Bokor, B., and L. Kajtár. "Transpired solar collectors in building service engineering: Combined system operation and special applications." International Review of Applied Sciences and Engineering 9, no. 1 (June 2018): 65–71. http://dx.doi.org/10.1556/1848.2018.9.1.9.

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One of the easiest ways to integrate renewable sources of energy into the heat producing system of a building is the application of transpired solar collectors. They are widespread in North America, where air heating is a common heating alternative, but they are gaining bigger share in the European solar thermal market nowadays. Their simple construction, maintenance-free operation and high working efficiency result in low capital and operating costs. The combination of TSC with other system elements results in additional benefits. Preheating the combustion air of large-scale boilers results in the increase of boiler efficiency and thus the reduction of natural gas consumption and CO2 emission. Whether to choose TSC or heat recovery unit for a certain air conditioning system has to be investigated by examining efficiency-influencing factors of both systems. Besides solar air heating, transpired solar air collectors can reduce the cooling demand on a building. Roof ventilation and nocturnal radiant cooling are two alternatives, which are being presented in the current paper.

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Panchasara, Heena, and Nanjappa Ashwath. "Effects of Pyrolysis Bio-Oils on Fuel Atomisation—A Review." Energies 14, no. 4 (February 3, 2021): 794. http://dx.doi.org/10.3390/en14040794.

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Bio-oils produced by biomass pyrolysis are substantially different from those produced by petroleum-based fuels and biodiesel. However, they could serve as valuable alternatives to fossil fuels to achieve carbon neutral future. The literature review indicates that the current use of bio-oils in gas turbines and compression-ignition (diesel) engines is limited due to problems associated with atomisation and combustion. The review also identifies the progress made in pyrolysis bio-oil spray combustion via standardisation of fuel properties, optimising atomisation and combustion, and understanding long-term reliability of engines. The key strategies that need to be adapted to efficiently atomise and combust bio-oils include, efficient atomisation techniques such as twin fluid atomisation, pressure atomisation and more advanced and novel effervescent atomisation, fuel and air preheating, flame stabilization using swrilers, and filtering the solid content from the pyrolysis oils. Once these strategies are implemented, bio-oils can enhance combustion efficiency and reduce greenhouse gas (GHG) emission. Overall, this study clearly indicates that pyrolysis bio-oils have the ability to substitute fossil fuels, but fuel injection problems need to be tackled in order to insure proper atomisation and combustion of the fuel.

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Journal articles on the topic 'Combustion air preheating'

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