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1
Enescu, Maria Cristiana, C. Marius Vlădulescu, Aurel Gaba, Vasile Bratu, Elena Valentina Stoian, and Ivona Camelia Petre. "Cold End Corrosion Avoiding by Using a New Type of Air Combustion Pre-Heater." Materials Science Forum 907 (September 2017): 157–63. http://dx.doi.org/10.4028/www.scientific.net/msf.907.157.
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This paper analyzes the possibility of reducing the cold end corrosion in boilers and furnaces by using a new type of air combustion pre-heater. Cold end corrosion appears due to catalytic oxidation of the sulfur dioxide to sulfur trioxide and then due to the sulfuric acid condensation at dew point. Calculating dew points of various acid gases and options for reducing cold end corrosion of heat recovery exchangers are presented. For avoiding the cold end corrosion we design a new type of air combustion pre-heater for boilers and furnaces. Also, the tube skin temperature of the first row of pipes of the actual air pre-heater was simulated with this computer program, in order to determine whether this temperature is lower than acid dew point of flue gas. With the simulation for this configuration of the actual combustion air pre-heater, the skin temperature for the first row (for the combustion air flow) of tubes from the upper bundle was TS = 134 °C. A way to reduce the cold end corrosion in the combustion air pre-heaters is raising the temperature of the combustion air at the air pre-heater entrance. This solution involves taking a quantity of preheated air, recirculation and then reintroducing it in the air pre-heater. In the same time, this solution avoiding to use the steam radiator, mounted after the fan, for pre-heating the combustion air from 1°C to 45°C. Thus, the furnaces equipped with the new combustion air pre-heater and modern low NOx burners made a fuel economy about 3%.
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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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Hunter, S. C., and R. E. Hall. "Refinery Process Heater NOx Control by Staged Combustion Air Lances." Journal of Engineering for Gas Turbines and Power 110, no. 2 (April 1, 1988): 185–89. http://dx.doi.org/10.1115/1.3240100.
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A vertically fired natural-draft petroleum-refinery crude-oil process heater was modified to reduce oxides of nitrogen (NOx) emissions by installing staged combustion air lances. Baseline NO emissions firing refinery gas before modification were measured to be 100 to 125 parts per million by volume, dry, corrected to 3 percent oxygen. Staged combustion air lances were installed to bypass combustion air around the burners to achieve staged combustion. With the modification, an average reduction of 64 percent in NO emissions was observed over a 30-day test period, with NO emissions of 25 to 50 ppm, dependent on the excess air. This method of combustion modification can be applied to most vertically fired process heaters where flame length increased by a factor of 2 to 4 would not cause flame impingement.
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Irawan, Irawan, and Aqli Mursadin. "ANALISIS KINERJA AIR HEATER DI PLTU ASAM-ASAM UNIT 2." JTAM ROTARY 1, no. 1 (April 1, 2019): 17. http://dx.doi.org/10.20527/jtam_rotary.v1i1.1396.
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Indonesia as one of the largest coal producers utilizes this advantage by establishing a steam power plant, one of which is Borneo south PLTU power plant PT.PLN (persero) south of Borneo and Central Borneo Asam-Asam generation sector. One important component of PLTU is air heater to raise the combustion air temperature. Initial heating of ljungstrom type lattest regenerative air heater in PLTU Asam-Asam unit 2 is carried out cleaning and maintenance on seal and gas side surfaces to optimize heat transfer coefficient and ratio of air intake ratio exposed by forced draft fan and air heated by flue gas in heater air heater elements and transferred to the combustion chamber to make efficient use of new fuel. Measurements were carried out on August 9, 2017 for 2 hours to find out the average value of heat transfer coefficient and temperature comparison of entry and exit from air heater of Asam-Asam unit 2 steam power plant. This research was conducted to find out the value of heat transfer coefficient and air temperature ratio with measurement on the inlet and outlet for two hours. The results of the air heater performance analysis in in PLTU Asam-Asam unit 2 steam power plant in terms of the highest heat transfer coefficient was 62.75 W/m^2.℃ at 2:04 PM, while the lowest heat transfer coefficient was 62.37 W/m^2.℃ at 3:10 PM, and the average heat transfer coefficient is 62.50 W/m^2.℃ . While the highest water heater ratio 9.70 at 3:44 PM and the lowest ratio 8.32 at minute 3:09 PM, and the average water heater ratio 9.01. Heater water heater elements in good condition and performance in receiving and releasing heat. Keywords: Air Heater, Heat Transfer Coefficient, Temperature Ratio, Heating Elements
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Pachaiyappan, R., and J. Dasa Prakash. "Improving the Boiler Efficiency by Optimizing the Combustion Air." Applied Mechanics and Materials 787 (August 2015): 238–42. http://dx.doi.org/10.4028/www.scientific.net/amm.787.238.
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Air pre-heater and economizer are heat transfer surfaces in which air temperature and water temperature are raised by transferring heat from other media such as flue gas. Hot air is necessary for rapid combustion in the furnace and also for drying coal in milling plants. So an essential boiler accessory which serves this purpose is air pre-heater. The air pre-heater is not essential for operation of steam generator, but they are used where a study of cost indicates that money can be saved or efficient combustion can be obtained by their use. The decision for its adoption can be made when the financial advantages is weighed against the capital cost of heater. The efficiency of the boiler increases with the increase in the temperature of the combustion air used in the furnace. This is achieved by the increased temperature of the flue gas in the air preheater and economizer zone. This paper deals with the different ways to obtain the maximum heat from the flue gas travelling through the air preheater and the economizer zone to improve the boiler efficiency.
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Bee´r, J. M., and R. V. Garland. "A Coal-Fueled Combustion Turbine Cogeneration System With Topping Combustion." Journal of Engineering for Gas Turbines and Power 119, no. 1 (January 1, 1997): 84–92. http://dx.doi.org/10.1115/1.2815567.
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Cogeneration systems fired with coal or other solid fuels and containing conventional extracting-condensing or back pressure steam turbines can be found throughout the world. A potentially more economical plant of higher output per unit thermal energy is presented that employs a pressurized fluidized bed (PFB) and coal carbonizer. The carbonizer produces a char that is fed to the PFB and a low heating value fuel gas that is utilized in a topping combustion system. The topping combustor provides the means for achieving state-of-the-art turbine inlet temperatures and is the main contributor to enhancing the plant performance. An alternative to this fully coal-fired system is the partially coal, partially natural gas-fired air heater topping combustion cycle. In this cycle compressed air is preheated in an atmospheric pressure coal-fired boiler and its temperature raised further by burning natural gas in a topping gas turbine combustor. The coal fired boiler also generates steam for use in a cogeneration combined cycle. The conceptual design of the combustion turbine is presented with special emphasis on the low-emissions multiannular swirl burner topping combustion system and its special requirements and features.
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Hashimoto, T. "Combustion stability of a vitiated-air heater using coaxial injectors." Energy Conversion and Management 38, no. 10-13 (July 1997): 1083–92. http://dx.doi.org/10.1016/s0196-8904(96)00138-0.
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Ni, Pei Yong, Xiang Li Wang, and Sheng Li Wei. "Numerical Simulation of Thermodynamic Parameters during Diffusion Combustion for Vehicle Air Heater." Applied Mechanics and Materials 80-81 (July 2011): 783–87. http://dx.doi.org/10.4028/www.scientific.net/amm.80-81.783.
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The diffusion combustion of the air heater was numerically simulated at different excess air coefficient using Fluent software. The distributions of the temperature, gas flow velocity, and turbulence intensity were present. And the heat flux was calculated. The result showed that the excess air coefficient had a little effect on the maximum combustion temperature distribution. As the excess air coefficient increased, the axial temperature at first increased and then decreased, and in contrast both the total heat flux and radiation heat flux decreased. The radial temperature, velocity and turbulence intensity increased firstly and then decreased at the same operation condition. The measured exhaust temperature increased with time. At 90 second, it was about 250 °C, which showed good agreement with simulation result. This provides theory basis for the reform of the heater.
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Irodov, Vyacheslav, Maksym Shaptala, Kostiantyn Dudkin, Daria Shaptala, and Halyna Prokofieva. "Development of evolutionary search algorithms with binary choice relations when making decisions for pellet tubular heaters." Eastern-European Journal of Enterprise Technologies 3, no. 8(111) (June 30, 2021): 50–59. http://dx.doi.org/10.15587/1729-4061.2021.235837.
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A study was carried out and the optimization process was carried out for one of the types of equipment for autonomous heat supply using renewable resources – a tubular pellet heater. The research is expedient, since there is no mathematical model of the unit operation for the pellet combustion unit, there is only a set of experimental results indicating the inconsistency of the criteria presented to it. As a result of the research, new algorithms have been obtained: firstly, an algorithm for selecting (multi-criteria optimization) the operating mode of the unit for burning pellets of tubular heaters, and secondly, algorithms for choosing, according to several criteria, the parameters of the heat exchange unit of a tubular heater with a screen. A set of algorithms for multicriteria optimization with binary selection ratios has been developed for tubular pellet heaters in full, including a pellet combustion unit and a heat exchange unit. Selection functions have been defined for a pellet combustion unit using dimensionless complexes based on experimental results. For a block of a tubular heat exchanger with a screen, a selection function is built taking into account the criteria of functioning and a mathematical model of the heater in the form of a system of nonlinear ordinary differential equations. The practical significance of the algorithm for selecting the operating mode for the pellet combustion unit lies in the possibility of obtaining the most preferable (optimal, taking into account many criteria) parameters in the entire range of permissible parameters, and not only among the experiments carried out. The practical significance of optimization algorithms for a heat exchange unit lies in the ability to select specific parameter values during design – the thermal power of the heater, air flow, the length of the tubular part and the screen, their diameters, taking into account several selection criteria.
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Musavi, Zahra, Henrik Kusar, Robert Andersson, and Klas Engvall. "Modelling and Optimization of a Small Diesel Burner for Mobile Applications." Energies 11, no. 11 (October 25, 2018): 2904. http://dx.doi.org/10.3390/en11112904.
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While extensive research has been done on improving diesel engines, much less has been done on auxiliary heaters, which have their own design challenges. The study analyzes how to optimize the combustion performance of an auxiliary heater, a 6 kW diesel burner, by investigating key parameters affecting diesel combustion and their properties. A model of a small diesel heater, including a simulation of fuel injection and combustion process, was developed step-wise and verified against experimental results that can be used for scaling up to 25 kW heaters. The model was successfully applied to the burner, predicting the burner performance in comparison with experimental results. Three main variables were identified as important for the design. First, it was concluded that the distance from the ring cone to the nozzle is essential for the fluid dynamics and flame location, and that the ring cone should be moved closer to the nozzle for optimal performance. Second, the design of the swirl co-flow is important, and the swirl number of the inlet air should be kept above 0.6 to stabilize the flame location for the present burner design. Finally, the importance of the nozzle diameter to avoid divergent particle vaporization was pointed out.
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Yuan, Lei, and Chibing Shen. "Large eddy simulation of combustion instability in a tripropellant air heater." Acta Astronautica 129 (December 2016): 59–73. http://dx.doi.org/10.1016/j.actaastro.2016.08.002.
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Zaki, M. Faza Ghani, and Abdul Ghofur. "ANALISA EFEKTIVITAS HEAT TRANSFER SAH PLTU DENGAN METODE ASME 4.0 dan 4.3." JTAM ROTARY 2, no. 1 (April 20, 2020): 39. http://dx.doi.org/10.20527/jtam_rotary.v2i1.2003.
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Pemanas udara adalah salah satu peralatan tambahan yang sangat penting dalam penggunaan perpindahan panas dalam boiler, di mana peralatan ini berfungsi untuk memanaskan udara untuk pembakaran dengan menggunakan panas dari sisa gas panas dari pembakaran sebelum dikirim ke cerobong asap. Untuk menjaga kinerja pemanas udara, maka analisis efektivitas perpindahan panas pada pemanas udara dilakukan dengan uji kinerja menggunakan metode ASME PTC 4.0 dan ASME PTC 4.3. Pada data commissioning, SAH unit 1 memiliki efisiensi sebesar 58,69%. Namun, dari hasil analisis penelitian perpindahan panas di Secondary Air Heater unit 1 pada 2 Maret 2018, efisiensi dihitung sebesar 38,96%, terjadi penurunan sebesar 19,73%, hal ini disebabkan oleh slagging on permukaan elemen dalam SAH dan kebocoran pada pipa SAH. selanjutnya, perbaikan dilakukan dengan melakukan jelaga dan melakukan pengelasan pada pipa bocor menggunakan teknik pengelasan TIG (Tungsten Inert Gas). Setelah itu analisis dilakukan dengan tes kinerja yang diadakan pada 21 Maret 2018 dan mendapat peningkatan 11,34% menjadi 50,3%. Air heaters are one of the auxiliary equipment that are very important in the use of heat transfer in a boiler, where this equipment serves to heat the air for the combustion by using heat from the residual hot gas from the combustion before sending it to the chimney. To maintain the performance of air heater, then the analysis of the effectiveness of heat transfer on air heater is carried out with a performance test using the ASME PTC 4.0 and ASME PTC 4.3 methods. On commissioning data, SAH unit 1 has an efficiency in amount of 58.69%. However, from the result of a research analysis of heat transfer in Secondary Air Heater unit 1 on March 2 2018, the efficiency was counted in amount of 38.96%, there has been a decrease of 19,73%, this was caused by slagging on the surface of the element in SAH and leakage on SAH pipes. subsequently, repairs are carried out by doing soot blowing and perform welding on the leaking pipe using the TIG (Tungsten Inert Gas) welding technique. Afterwards the analysis is carried out with a performance test was held on March 21, 2018 and got an increase of 11.34% to 50.3%.
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Fotev, Vasko, Miroljub Adzic, and Aleksandar Milivojevic. "Influence of combustion instabilities on the heater appliance with atmospheric gas burner and their elimination by cross flow of air." Thermal Science 20, no. 5 (2016): 1753–63. http://dx.doi.org/10.2298/tsci151211126f.
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This paper presents results of experimental investigation on elimination of combustion oscillations caused by new low pollution burner which was integrated in a gas heater. The method is known as a passive method, based on introducing the air in the combustion chamber. Because the efficacy of the method is highly dependent of the way the air is injected some methods were investigated and compared. The paper also presents effects on pollution characteristics during its operation in the unstable regime.
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Liu, Feng Guo, Xue Yi You, Qi Wang, Wen Bo Liu, and Rui Zhang. "CO Emission Characteristics in a Designed Premixed Burner." Advanced Materials Research 322 (August 2011): 205–8. http://dx.doi.org/10.4028/www.scientific.net/amr.322.205.
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Carbon monoxide (CO) formed in gas instantaneous water heater combustion systems is a significant pollutant source in the domestic environment. With the advance of reaction science and computer performance, mathematical modeling is working for comprehensive simulation of CO formation to provide a valuable tool to study the insight and understanding of the CO reaction of combustion systems. In this approach, the chemical reactions of combustion are described by nine species and six steps. Numerical results show that the predicted CO level is less than 0.1% when diameter of round fire hole is 0.6 or 0.7mm and the excess air ratio is 1.3. The vortex appearing between two bunch of round fire holes results in a thermal agglomeration and O2 decrease. At this place, CO2 is decomposed into CO and O and CO and the reaction is mainly controlled by CO2 pyrolysis. At this time, the increase of excess air is helpful to reduce CO production. Our results indicate the excess air ratio should be kept above 1.3 to meet with the fifth class of NO emission in gas instantaneous water heater standard GB 6932－2001.
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Yoon, Jaeock. "The Effect of Natural Ventilation in a Small Room with an Unvented Gas-Fired Heater." Key Engineering Materials 277-279 (January 2005): 583–88. http://dx.doi.org/10.4028/www.scientific.net/kem.277-279.583.
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In small buildings and residences in Korea, unvented or improperly vented combustion appliances are used to heat rooms. These heaters are mostly gas-fired portable equipment used for auxiliary heating. Although their maintenance cost is very low, unvented gas-fired heaters emit air contaminants such as carbon dioxide and carbon monoxide. If there is inadequate ventilation and even a little fresh air with oxygen comes into the appliances, combustion occurs less efficiently and heaters generate more air contaminants. Natural ventilation is the best way to prevent air pollution in small buildings. Outdoor air has a lot of oxygen and can reduce air pollution. The objective and scope of this research is to predict the distribution of indoor air pollution, according to the results of field measurements and CFD (Computational Fluid Dynamics) simulations. In a room of 6.4m×3.1m×2.6m in size, air contaminants (CO2 and CO) and air temperature were measured in two instances--with natural ventilation and without natural ventilation. After comparing the results obtained with computer simulation and field measurements, passive control methods to improve indoor air quality in a room are proposed.
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Wang, Jian, Jiang Zhou Shu, Guo Hui Huang, and Ai Peng Jiang. "Measurement and Control of the Gas Turbine Inlet Air Cooling System." Applied Mechanics and Materials 220-223 (November 2012): 439–42. http://dx.doi.org/10.4028/www.scientific.net/amm.220-223.439.
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As a constant-column power generating machine, the combustion turbine has a direct proportion of its output to the quantity of input air. Therefore, when the ambient air temperature rises higher in summer, the effect of combustion turbine is decreasing. In order to enhance the efficiency of combustion turbine in summer, two sets of inlet air cooling system (IACS) were installed in PG6551(B) combustion turbines in Jinhua, Zhejiang, China. Two low-pressure evaporators were installed in the caudal flue of the waste heat boiler, therefore, the produced saturation steam drives a single-effect lithium bromide absorption chiller to cool the input air of combustion turbines to raise the output power of combustion turbine in summer; or supplies the low-pressure heater to heat the condensated water from the deaerator of the steam turbine in winter. A measurement and control system (MCS) of the new-added inlet air cooling equipments was developed. Based on the framework of DCS (Distributed Computer System), the M&C system has the IACS work correctly and easily. The structure and functions of the M&C is described in detail.
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Bradna, J., and J. Malaťák. "Flue gases thermal emission concentration during waste biomass combustion in small combustion device with manual fuel supply." Research in Agricultural Engineering 62, No. 1 (March 31, 2016): 1–8. http://dx.doi.org/10.17221/36/2014-rae.
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he aim of the experiments is determination of emission concentrations in the observed substances produced in exhaust gas during combustion of various mixtures of waste biomass compacted samples. The samples were pressed into the form of briquettes with a diameter of 65 mm. During the actual measurements the following parameters were monitored: emissions of carbon dioxide (CO<sub>2</sub>), carbon monoxide (CO), nitrogen oxides (NO<sub>x</sub>) and flue gas temperature depending on the excess air coefficient. Measurements of emission parameters were carried out in storage heater fireplace with nominal heat output of 8 kW. During the measurements high concentrations of carbon monoxide in excess of the value of 5,000 mg/m<sup>3</sup> were determined, especially in the samples of waste from corn cleaning and wheat straw. The results show an excess air factor optimum adjustment on value 3, where the combustion device achieves optimum parameters of CO and NO<sub>x</sub> emissions. The results of emission measurements confirmed that the excess air is a very important operating variable which affects both monitored emissions concentrations and the combustion temperature in the fireplace.
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Shi, Deyong, Wenyan Song, Jingfeng Ye, Bo Tao, Yanhua Wang, and Qiang Fu. "Experimental Investigation of Reacting Flow Characteristics in a Dual-Mode Scramjet Combustor." International Journal of Turbo & Jet-Engines 35, no. 4 (December 19, 2018): 321–30. http://dx.doi.org/10.1515/tjj-2015-0014.
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Abstract In this work, a hydrogen fueled dual-mode scramjet combustor was investigated experimentally. Clean and dry air was supplied to the combustor through a Mach 2 Nozzle with a total temperature of 800 K and a total pressure of 800 kPa. The high enthalpy air was provided by an electricity resistance heater. Room temperature hydrogen was injected with sonic speed from injector orifices vertically, and downstream the injector a tandem cavity flame holder was mounted. Except wall pressure profiles, velocity and temperature profiles in and at exit of the combustor were also measured using hydroxyl tagging velocimetry (HTV) and tunable diode laser absorption spectroscopy (TDLAS) respectively. Results showed that combustion occurred mainly at the bottom side of the combustor. And there were also an extreme disparity of the velocity and temperature profiles along the Y direction, i.e. the transverse direction.
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곽기주, 강정일, 정형길, and CHO KI-HYUN. "Combustion Characteristics of the Waste Edible-Oil and Heavy Oil on Hot Air Heater." Journal of the Korean Society of Mechanical Technology 11, no. 4 (December 2009): 113–17. http://dx.doi.org/10.17958/ksmt.11.4.200912.113.
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Vollmer, M. K., S. Walter, J. Mohn, M. Steinbacher, S. W. Bond, T. Röckmann, and S. Reimann. "Molecular hydrogen (H2) combustion emissions and their isotope (D/H) signatures from domestic heaters, diesel vehicle engines, waste incinerator plants, and biomass burning." Atmospheric Chemistry and Physics Discussions 12, no. 3 (March 5, 2012): 6839–75. http://dx.doi.org/10.5194/acpd-12-6839-2012.
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Abstract. Molecular hydrogen (H2), its stable isotope signature (δD), and the key combustion parameters carbon monoxide (CO), carbon dioxide (CO2), and methane (CH4) were measured from various combustion processes. H2 in the exhaust of gas and oil-fired heaters and of waste incinerator plants was generally depleted compared to ambient intake air, while CO was significantly elevated. These findings contradict the often assumed co-occurring net H2 and CO emissions in combustion processes and suggest that previous H2 emissions from combustion may have been overestimated when scaled to CO emissions. For the heater exhausts, H2 and δD generally decrease with increasing fuel-to-air ratio, from ambient values of ∼0.5 ppm and +130‰ to 0.2 ppm and −206‰, respectively. These results are interpreted as a combination of an isotopically light H2 source from fossil fuel combustion and a D/H kinetic isotope fractionation of hydrogen in the advected ambient air during its partial removal during combustion. Diesel exhaust measurements from dynamometer test stand driving cycles show elevated H2 and CO emissions during cold-start and some acceleration phases. Their molar H2/CO ratios are <0.25, significantly smaller than those for gasoline combustion. Using H2/CO emission ratios, along with CO global emission inventories, we estimate global H2 emissions for 2000, 2005, and 2010. For road transportation (gasoline and diesel), we calculate 8.6 ± 2.1 Tg, 6.3 ± 1.5 Tg, and 4.1 ± 1.0 Tg, respectively, whereas the contribution from diesel vehicles has increased from 5% to 8% over this time. Other fossil fuel emissions are believed to be negligible but H2 emissions from coal combustion are unknown. For residential (domestic) emissions, which are likely dominated by biofuel combustion, emissions for the same years are estimated at 2.7 ± 0.7 Tg, 2.8 ± 0.7 Tg, and 3.0 ± 0.8 Tg, respectively. Our wood combustion measurements are combined with results from the literature to calculate biomass burning emissions. For these estimates, we propose a molar H2/CH4 ratio of 3.3, when using CH4 emission inventories. When using this approach, our resulting global biomass burning H2 emissions agree well with published results, suggesting that CH4 emissions may be a good proxy for H2 emissions.
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Gużda, Arkadiusz, and Norbert Szmolke. "Analysis of Domestic Hot Water Production Efficiency for Detached Houses." Applied Mechanics and Materials 797 (November 2015): 185–91. http://dx.doi.org/10.4028/www.scientific.net/amm.797.185.
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The article compares two means for domestic hot water production (DHW) for a detached house that is using gas boiler with a closed combustion chamber and air source heat pump water heater (ASHPWH). An analysis of domestic hot water production using an air source heat pump was made taking into account coefficient of performance listed according to the new BS EN 16147 standard. The analysis of outlay related to the investment and operating costs was also performed. Ultimately, the more profitable choice for domestic hot water production was made.
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Kobysh, E. I., A. I. Simkin, and V. P. Kravchenko. "Heating of the packing in a blast-furnace air heater with an internal combustion chamber." Steel in Translation 44, no. 1 (January 2014): 38–42. http://dx.doi.org/10.3103/s0967091214010094.
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Basok, B. I., and V. V. Gotsulenko. "Calculating the parameters of self-oscillations in the vertical combustion chamber of the blast-furnace air heater during unstable combustion." Thermal Engineering 62, no. 1 (December 17, 2014): 58–63. http://dx.doi.org/10.1134/s0040601515010024.
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Borisov, I. I., and A. A. Khalatov. "THERMOPHYSICAL ANALYSIS OF THE PARAMETERS OF A BIOMASS FUELED MICRO–CHP UNIT WITH A STIRLING ENGINE." Thermophysics and Thermal Power Engineering 42, no. 4 (August 27, 2020): 26–32. http://dx.doi.org/10.31472/ttpe.4.2020.3.
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A typical scheme of a biomass fueled micro-CHP unit with a Stirling engine, including a combustion chamber, a Stirling Engine, a recuperator and water heater, is considered. A brief overview of the main biomass combustion methods used in this installation is made.
Thermophysical analysis was carried out on the basis of solving a system of equations: the reaction equation for wood biomass combustion, the equations of both the general heat balance and the heat balance of parts of CHP unit, as well as the equation of energy conservation at flows mixing in the combustion chamber, taken into account the heat input and losses. The relationship for calculating the theoretical temperature in the combustion chamber and heat flux in the recuperatoris obtained. The last equation is obtained in dimensionless form. The theoretical temperature in the combustion chamber and the heat flux in the recuperator have been calculated, the influence of the main factors has been analyzed - the efficiency of heat exchange in the recuperator, the share of the total air flow passing through the recuperator, the excess air ratio, dimensionless heat losses and heat flux on the hot heat exchanger of the Stirling engine.
It is shown that the temperature in the combustion chamber decreases with a decrease in the efficiency of the recuperator and with an increase in the excess air ratio. A significant influence of heat losses in the combustion chamber on the heat flux in therecuperatorwas found. Under certain conditions (high heat losses and high heat exchange on the hot heat exchanger of the Stirling engine), the recuperator is not neededatall.
It is also shown that the share of the total air flow passing through the recuperator has a significant effect on the heat flux in the recuperator. Thus, when the air flow passing through the recuperator is reduced by 2 times, the heat flow is reduced by 5 times. Therefore, it is necessary to minimize the air flow bypassing the recuperator. As a result of thermophysical analysis, the optimal value of the excess air ratio was obtained, which is 1.7 ... 1.8.
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Hrnčířová, Michaela, Michal Špiláček, and Jiří Pospíšil. "SIZE ANALYSIS OF SOLID PARTICLES AT THE EXPERIMENTAL DEVICE FOR MULTI-STAGE BIOMASS COMBUSTION." Acta Polytechnica 54, no. 1 (February 28, 2014): 22–27. http://dx.doi.org/10.14311/ap.2014.54.0022.
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This paper presents the results of an analysis of ash content particles produced in biomass combustion at an experimental device. The main parts of the device are: the water heater, the gasifying chamber, the air preheater, and the fuel feeder. This device can be modified for combustion in an oxygen-enriched atmosphere. Sawdust and wood chips were used as fuel, and were laid loosely into the device. Ash specimens were extracted from various parts of the device. For the measurements themselves, we used the Analysette 22 MicroTec Plus universal laser diffraction device manufactured by the Fritch Company, in the size range from 0.08 μm to 2000 μm. The device utilizes laser diffraction for particle size analysis.
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Kijo-Kleczkowska, Agnieszka. "Analysis of coal suspensions evolution during combustion process." International Journal of Numerical Methods for Heat & Fluid Flow 30, no. 5 (July 24, 2019): 2551–61. http://dx.doi.org/10.1108/hff-03-2019-0200.
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Purpose The paper aims to undertake coal–water suspension combustion, in air and in fluidised bed conditions. Fluidised bed conditions are the best to efficiently and ecologically use fuel. Combustion technologies using coal–water fuels create a number of new possibilities for organising combustion processes so that they fulfil contemporary requirements. The aim of the process was to show how the specificity of combustion of coal–water suspensions in the fluidised bed changes the kinetics of the process, compared to combustion in the air stream. Changes of the surface and the centre temperature and mass of the coal suspension during combustion, and evolution of fuels during process are presented in the paper. Design/methodology/approach Experimental character of the research required the research stand preparation, as well as working out of the measurements methodology (Kijo-Kleczkowska, 2010). The research stand (Figure 1a) was made of ceramic blocks in which the quartz pipes were put. The heating element of the stand comprised three heating coils of 2.0 kW. Each heater was placed in small quartz tubes. These tubes were built into the quartz tube which was thermally insulated by fibre material Al2O3 and which was covered with steel sheet. Combustion chamber constituted the quartz pipe, which was additionally insulated thermally, to keep the necessary temperature of the entering gas and to reduce the heat loss. The compressed air was transported to the quartz tube through the electro-valve, the control valve and the rotameter. This study stand allowed for the comparison of the combustion process of coal–water suspensions, in air and in fluidised bed conditions. To study in the fluidised bed, quartz sand was used. Depending on the velocity of air inflowing from the bottom of the bed, different bed characteristics were obtained – from bubble – to circulating-beds. The fumes were removed outside by means of a fan fume cupboard. To regulate the temperature inside the combustion chamber, the Lumel microprocessor thermoregulator was applied. The regulator controlled the work of tri-phase Lumel power controller supplying the main heating elements (gas heater) allowing to measure the actual temperature with accuracy of measurements to 20°C. The temperature measurements in the combustion chamber were carried out by means of the thermocouple NiCr-NiAl. To establish the centre and surface temperature and mass of the fuel, a special instrument stalk was constructed (Figure 1b). It had two thermocouples PtRh10-Pt, placed in two thin quartz tubes connected to the scale. One of the thermocouples was located inside the fuel, while the other served as a basket which was to support the fuel. It also touched the surface of the fuel. The thermocouples were connected to the computer to record the experimental results. The essential stage of the preliminary work was to make out a suspension, which was a mixture of fuel dust (hard coal dust or dried coal-sludge dust) and water. To produce the suspension it was necessary to prepare fuel dust after grinding and sifting it, and then adding water, to obtain a suspension moisture of 20, 35 or 50 per cent. The hard coal was applied in the research. The analysis of fuel dust (in air-dry state) is shown in Table I. The testing of the porosity of fuel was made with mercury porosimetry, carried out in the Pascal 440 apparatus, applying pressure from 0.1 to 200 MPa. This method involves the injection of mercury into the pores of the fuel, using high pressures (Kijo-Kleczkowska, 2010). Findings 1. Under experimental conditions, during combustion in the fluidised bed, intensive heating of the suspension is observed in the initial stage of the process, followed by the removal of heat from the suspension by the contacting quartz material, leading to lowering of the average fuel temperature and extension of the combustion time, compared to the process carried out in air. 2. Measurements using mercury porosimetry enable the identification of the change of suspension porosity. 3. Devolatilisation and combustion of volatiles lead to an increase in the pores’ size in the fuel and their coalescence. 4. Combustion of fuel leads to the development of cracks in the suspension, and its structure changes under the influence of temperature. Cracks are caused by the formation of thermal stresses inside the fuel. 5. Under experimental conditions, suspension combustion in the fluidised bed causes an increase in volume participation of pores, with larger sizes of pores (3,500-5,000 nm), compared to combustion in the air. Originality/value The paper undertakes the evolution of suspension fuel, made of a hard coal and a coal-sludge, during combustion in air and in the fluidised bed.
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Vollmer, M. K., S. Walter, J. Mohn, M. Steinbacher, S. W. Bond, T. Röckmann, and S. Reimann. "Molecular hydrogen (H<sub>2</sub>) combustion emissions and their isotope (D/H) signatures from domestic heaters, diesel vehicle engines, waste incinerator plants, and biomass burning." Atmospheric Chemistry and Physics 12, no. 14 (July 19, 2012): 6275–89. http://dx.doi.org/10.5194/acp-12-6275-2012.
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Abstract. Molecular hydrogen (H2), its stable isotope signature (δD), and the key combustion parameters carbon monoxide (CO), carbon dioxide (CO2), and methane (CH4) were measured from various combustion processes. H2 in the exhaust of gas and oil-fired heaters and of waste incinerator plants was generally depleted compared to ambient intake air, while CO was significantly elevated. These findings contradict the often assumed co-occurring net H2 and CO emissions in combustion processes and suggest that previous H2 emissions from combustion may have been overestimated when scaled to CO emissions. For the gas and oil-fired heater exhausts, H2 and δD generally decrease with increasing CO2, from ambient values of ~0.5 ppm and +130‰ to 0.2 ppm and −206‰, respectively. These results are interpreted as a combination of an isotopically light H2 source from fossil fuel combustion and a D/H kinetic isotope fractionation of hydrogen in the advected ambient air during its partial removal during combustion. Diesel exhaust measurements from dynamometer test stand driving cycles show elevated H2 and CO emissions during cold-start and some acceleration phases. While H2 and CO emissions from diesel vehicles are known to be significantly less than those from gasoline vehicles (on a fuel-energy base), we find that their molar H2/CO ratios (median 0.026, interpercentile range 0.12) are also significantly less compared to gasoline vehicle exhaust. Using H2/CO emission ratios, along with CO global emission inventories, we estimate global H2 emissions for 2000, 2005, and 2010. For road transportation (gasoline and diesel), we calculate 8.3 ± 2.2 Tg, 6.0 ± 1.5 Tg, and 3.8 ± 0.94 Tg, respectively, whereas the contribution from diesel vehicles is low (0.9–1.4%). Other fossil fuel emissions are believed to be negligible but H2 emissions from coal combustion are unknown. For residential (domestic) emissions, which are likely dominated by biofuel combustion, emissions for the same years are estimated at 2.7 ± 0.7 Tg, 2.8 ± 0.7 Tg, and 3.0 ± 0.8 Tg, respectively. For biomass burning H2 emissions, we derive a mole fraction ratio ΔH2/ΔCH4 (background mole fractions subtracted) of 3.6 using wildfire emission data from the literature and support these findings with our wood combustion results. When combining this ratio with CH4 emission inventories, the resulting global biomass burning H2 emissions agree well with published global H2 emissions, suggesting that CH4 emissions may be a good proxy for biomass burning H2 emissions.
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Zheng, Peijun, Peng Liu, and Yeqi Zhang. "Economic Assessment and Control Strategy of Combined Heat and Power Employed in Centralized Domestic Hot Water Systems." Applied Sciences 11, no. 10 (May 11, 2021): 4326. http://dx.doi.org/10.3390/app11104326.
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With the increasing application of CHP and an industry transition to distributed energy, it is necessary to make a comprehensive economic analysis and comparison of the entire lifetime of CHP from the net present value (NPV), payback period, and cost-saving ratio (CSR). Five systems, including micro-CHP, gas boiler (GB), air-source heat pump (ASHP), domestic gas-fired heater and domestic electric hot water-heater, are simulated. First, this paper takes annual heat use efficiency (AHUE) into account to compare the economy of each domestic hot water (DHW) system. The results show that a domestic gas-fired heater system is the most economical option in the AHUE of 31.28%. The economic influence of CHP and gas-fired heater under different AHUE are then analyzed. The results show that the DHW system based on CHP is the best when the AHUE is more than 55.35%. Finally, three different operation strategies of CHP are considered in this paper. From the perspective of annual energy cost and payback, the internal combustion-based CHP with thermal energy system (TES) is superior to the other two strategies being studied. Considering the optimal economic benefits, the CSR of the three different operation strategies is 41.3%, 69.69% and 69.77%, respectively.
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Keywood, Melita, Helen Guyes, Paul Selleck, and Rob Gillett. "Quantification of secondary organic aerosol in an Australian urban location." Environmental Chemistry 8, no. 2 (2011): 115. http://dx.doi.org/10.1071/en10100.
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Environmental contextParticulate matter is detrimental to human health necessitating air quality standards to ensure that populations are not exposed to harmful levels of air pollutants. We quantified, for the first time in an Australian city, secondary organic aerosol produced in the atmosphere by chemical reactions, and show that it constitutes a significant fraction of the fine particulate matter. Secondary organic aerosol should be considered in regulations to control particulate matter and ozone. AbstractThe contribution of secondary organic aerosol (SOA) to particulate mass (PM) in an Australian urban airshed is quantified for the first time in this work. SOA is estimated indirectly using the elemental carbon tracer method. The contribution of primary organic carbon (OC) to PM is determined using ambient air quality data, which is used to indicate photochemical activity and as a tracer for a general vehicular combustion source. In addition, levoglucosan concentrations were used to determine the contribution of wood heater emissions to primary OC. The contribution of bushfire smoke to primary OC emissions was determined from the organic and elemental carbon (OC/EC) ratios measured in bushfire source samples. The median annual SOA concentration determined in this work was 1.1 µg m–3, representing ~13% of PM2.5 median concentrations on an annual basis (assuming a ratio of organic mass (OM) to OC of 1.6). Significantly higher SOA concentrations were determined when bushfire smoke affected the airshed; however, the SOA fraction of PM2.5 was greatest during the autumn and early winter months when the formation of inversions allows build up of particles produced by domestic wood-heater emissions.
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Bondrea, Dana Andreya, Lucian Mihaescu, Gheorghe Lazaroiu, Ionel Pisa, and Gabriel Negreanu. "Researches on the mixture limits of animal fats with liquid hydrocarbons for combustion at industrial level." E3S Web of Conferences 112 (2019): 02001. http://dx.doi.org/10.1051/e3sconf/201911202001.
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The experimental research has highlighted the variety of possibilities of combustion of animal fat from bovine and swine mixed with liquid hydrocarbons. Previous research has established that the upper limit for an efficient combustion was 30 %. For a perfect mixing, the lower temperature limit was set to 40 °C. In the fuel laboratory, at the department TMETF was determined the viscosity of the mixtures for different proportions. The values obtained for various concentrations and preheating temperatures were close to the values for liquid hydrocarbons. The experimental researches have studied the combustion of the mixture using a mechanically spraying burner with constant pressure between 14 and 18 bar. The aspiration of the mixture is done from a specially designed tank; this tank is equipped with an electric heater, in order to maintain the mixture at a constant temperature between 40 °C to 50 °C. After that, the burner heats again the mixture with an integrated heating device up to 75 °C. The burner is also equipped with an air blower, pump and a calibrated nozzle. The combustion resulted from the experimental boiler with a power rated to 55 kW were monitored with a thermal vision camera and an exhaust gas analyser. This research has demonstrated the viability of using this type of mixtures in energetic burning equipment designed for liquid hydrocarbons.
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Bustan, M. Djoni. "Effects of Steam Injection Flow in Burner and Outside Water Tube to the Increasing of Boiler Temperature." ASEAN Journal of Chemical Engineering 7, no. 1 & 2 (June 1, 2007): 120. http://dx.doi.org/10.22146/ajche.50134.
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Energy is an expensive basic need for human life, especially energy from fossils, such as crude oil, gas, and coal. In an oil refinery factory or electrical generator unit, where heat is most dominantly utilized, the boiler is used to generate steam. The main problem in a boiler is its uncompleted combustion process because of the incomplete ratio of air–fuel. This problem is caused by the addition of deposits or sealing inside and outside of the tube fire heater which will reduce the performance of fired heater. The objective of this research is to study the effect of steam flow variation on burner and tubing for increasing heat and temperature as well as the quality of steam. This research used a package boiler B&W series 1986 model which can be seen at an oil refinery factory or steam power electrical generator unit in Indonesia. This package boiler has 50kg/hours steam production capacity, qualified superheated steam, maximum pressure and temperature at 7kgs/cms2 and 700oC. Quantitatively, the achievable heat efficiency which corresponded to the temperature increase caused by the steam injection is 41.25% and the specific enthalpy is 12.07%.
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Moore, R. G., C. J. Laureshen, M. G. Ursenbach, S. A. Mehta, and J. D. M. Belgrave. "Combustion/Oxidation Behavior of Athabasca Oil Sands Bitumen." SPE Reservoir Evaluation & Engineering 2, no. 06 (December 1, 1999): 565–71. http://dx.doi.org/10.2118/59483-pa.
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Summary Oils that are potential candidates for in situ combustion recovery processes are often screened by means of their oxidation characteristics: in particular, the kinetics of the ignition process and the transition from low-temperature to high-temperature oxidation through what is known as the "negative temperature gradient region." These characteristics are readily studied in ramped-temperature oxidation tests, which involve the controlled heating of recombined, oil-saturated cores in a one-dimensional plug flow reactor under a flowing stream of air (or oxygen-containing gas). The purpose of these tests is to study the global oxidation behavior and reaction kinetics under controlled conditions, with the end purpose of providing realistic data for incorporation into a numerical simulator which can be used to predict field performance. A ramped-temperature oxidation apparatus was used to conduct a detailed, two-year parametric study of the oxidation characteristics of Athabasca Oil Sands bitumen. The text matrix involved various levels of pressure, gas injection rate, oxygen content of the injected gas, and maximum ramptemperature. This paper details the principal findings for the 45-test study;especially the need to maintain high reaction temperatures >380°C) in order to mobilize and produce heavy oils under conditions of dry in situ combustion. Design considerations and operational guidelines for successful field projectsarising from the results of this study are also discussed. Introduction In order to successfully exploit the vast potential of processes based on the injection of air or an oxygen-containing gas for the recovery of conventional and heavy oils, it is necessary to understand the nature of the oxidation reactions which are involved. The traditional definition of in situ combustion, which is based on the high-temperature combustion of a coke-like fuel, does not explain the combustion behavior which is observed in many field projects or even in laboratory combustion tube experiments. For this reason, a number of experiments have been developed which concentrate on the global oxidation kinetics. These studies normally involve exposing the crude oil to a programmed rate of heating while in contact with the oxidizing gas. The oxidation kinetics are then observed using effluent gas analysis techniques,1–7 and differential thermal techniques such as the differential thermal analysis (DTA) work of Vossoughi et al.,8 the pressurized differential scanning calorimetry (PDSC) studies of Phillips et al.9 and Belkharchouche and Hughes,10 and the accelerating rate calorimetry (ARC) technique of Yannimaras et al.11 Previous investigations of the oxidation reactions which occur during in situ combustion processes have shown the existence of at least two temperature ranges over which the oxygen uptake rates are significant. 2,4-7While Kisler and Shallcross have reported that the light (40.2°API) Australian oil which they studied exhibited at least three temperature ranges over which localized maxima in the oxygen uptake rate were observed, the majority of heavy oils for which oxidation data have been reported show only two distinct local maxima in the oxidation rates. For convenience, the two temperature ranges where elevated oxygen uptake or energy generation rates are observed are denoted as the low-temperature oxidation (LTO) and high-temperature combustion(HTC) regions. For heavy oils, the range of temperatures associated with the low-temperature oxidation region is roughly from 150 to 300°C, while the high-temperature combustion region generally corresponds to reaction temperatures in the range from 380 to 800°C. The transition temperature range which falls between the low-temperature oxidation and high-temperature combustion regions is characterized by reduced oxygen uptake and energy generation rates. The lower temperature portion of this transition range in which the oxygen uptake and energy generation rates decrease with increasing temperature is the "negative temperature gradient region" (NTGR). This behavior is illustrated in Fig. 1, which is the temperature history for a test involving a heater temperature of 350°C (near the upper end of the NTGR). This test, which was previously described by Moore et al.,12 shows that a distinct low-temperature reaction zone formed when the temperature was approximately 140°C and it propagated through the core for a short period of time as the heater continued its ramp towards the setpoint maximum temperature of 350°C At the end of the propagation period, the centerline temperatures remained very close to the heater temperature as the latter was increased over the temperature interval from 280 to 330°C It is apparent from the small temperature differences between all of the centerline locations and the heater that energy generation over this temperature interval was very low. A high-temperature reaction zone started to form when the temperature at the first thermocouple location attained 355°C. Fig. 2 provides the oxygen uptake history for the same test, and the data show that there were also two distinct periods of high oxygen uptake rates. The first period corresponds to the time that the lower-temperature reaction zone propagated through the core, and it is apparent that the prime mode of oxygen uptake is by reactions which do not result in the formation of carbon oxides. These reactions have been denoted as LTO reactions, although it should be noted that hydrogen conversion to water (which is normally classified as a combustion reaction) is included as a LTO reaction. Oxygen uptake rates associated with the second period correspond to the propagation of the high-temperature reaction zone. At these higher temperatures, oxygen consumption is primarily associated with the formation of carbon oxides. Oxygen uptake by LTO reactions is also significant, but this reflects the inclusion of hydrogen conversion to water as a LTO reaction. In essence, the oxidation reactions associated with the high-temperature propagating reaction zone are those which are normally designated as high-temperature combustion, in that the primary products are carbon oxides and water.
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Pronobis, Marek, Sylwester Kalisz, Kazimierz Mroczek, Andrzej Walewski, Robert Wejkowski, Wacław Wojnar, Waldemar Gądek, Tomasz Kress, Mateusz Tymoszuk, and Izabella Maj. "Studies on the effectiveness of SCR catalysts during combustion of pulverized coal." E3S Web of Conferences 82 (2019): 01014. http://dx.doi.org/10.1051/e3sconf/20198201014.
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The motivation of this paper is new NOx emission regulations according to IED Directive 2010/75/EU of EU which introduce the BAT’s conclusions as binding. The paper presents the methodology and results of research on the effectiveness of SCR catalysts during combustion of pulverised coal in a model furnace installed at the Institute of Power Engineering and Turbomachinery of the Silesian University of Technology (IPET). The aim of the research was to search for catalysts that could be placed in a regenerative rotary air heater - RAH-SCR. Two catalysts were tested: a commercial plate-type based on V2O5 and a prototype ceramic based on platinum. Presented results of investigation demonstrate a potentially high efficiency of RAH-SCR installations which can meet new environmental regulations of NOx emission. The highest NOx reduction efficiency (92.87%) was obtained for an industrial catalyst at 329°C, from about 436.3 to 31.1 mg/m3 as NO2 @ 6%O2 to 31,1. At lower temperature, 260°C maximum efficiency of NOx reduction does not exceed 60%, from 440,0 to 169,6 mg/m3. The placement of the catalyst in the RAH can also be a support for SNCR installations due to the increase in DeNOx efficiency and reduction of NH3 slip.
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Obaidullah, Md, Bram Svend, and De Ruyck Jacques. "Investigation of Optimal Dilution Ratio from a Dilution Tunnel Using in Particulate Matter Measurement." International Journal of Engineering Technology and Sciences 5, no. 1 (June 19, 2018): 17–33. http://dx.doi.org/10.15282/ijets.v5i1.2802.
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Combustion of fuels leads to the formation of gaseous and particulate matter pollutants that have an impact on air quality and the environment. Comparison to the gaseous emissions from stack, measuring of particulate matter (PM) needs extra attention because particles do not behave as a continuum. Dilution tunnels are used with the PM measuring instruments to dilute the hot exhaust gases leaving from the stack. The main focus of this study was to investigate the dilution ratio results obtained from a partial flow dilution tunnel. The partial flow dilution system consists of a porous tube diluter, an ejector diluter and an air heater. The dilution air flow settings into the porous tube diluter and ejector diluter are selected for a wide range of dilution ratios. Two mass flow controllers were used to regulate the flow of dilution air into the diluters. The experiments were conducted at the Renewable Energy Laboratory of the Vrije Universiteit Brussel (VUB).There were a total of fifteen experiments with four flow settings conducted. Dilution ratio (DR) is evaluated based on the ratio of the CO2 (dry) concentration in the raw sample to the diluted sample. The results obtained from the experiments with the partial flow diluters are limited between 34 and 110. The experimental results are also compared with other works and found quite similar
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Ruth, Lawrence A. "Advanced Coal-Fired Power Plants." Journal of Energy Resources Technology 123, no. 1 (October 30, 2000): 4–9. http://dx.doi.org/10.1115/1.1348270.
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The U.S. Department of Energy is partnering with industry to develop advanced coal-fired electric power plants that are substantially cleaner, more efficient, and less costly than current plants. Low-emission boiler systems (LEBS) and high-performance power systems (HIPPS) are based, respectively, on the direct firing of pulverized coal and the indirectly fired combined cycle. LEBS uses a low-NOx slagging combustion system that has been shown in pilot-scale tests to emit less than 86 g/GJ (0.2 lb/106 Btu) of NOx. Additional NOx removal is provided by a moving bed copper oxide flue gas cleanup system, which also removes 97–99 percent of sulfur oxides. Stack levels of NOx can be reduced to below 9 g/GJ (0.02 lb/106 Btu). Construction of an 80 MWe LEBS proof-of-concept plant is scheduled to begin in the spring of 1999. Engineering development of two different HIPPS configurations is continuing. Recent tests of a radiant air heater, a key component of HIPPS, have indicated the soundness of the design for air temperatures to 1150°C. LEBS and HIPPS applications include both new power plants and repowering/upgrading existing plants.
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Monhol, Filipe Arthur Firmino, and Marcio Ferreira Martins. "Ignition by Thermal Radiation of Polyethylene and Human Feces Combustible Wastes: Time and Temperature to Ignition." Advanced Materials Research 911 (March 2014): 373–77. http://dx.doi.org/10.4028/www.scientific.net/amr.911.373.
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Due to the growing energy demands of the world and the rapid depletion of fossil fuels, it is necessary to study new energy sources. The waste have a great potential to be tapped, as besides being a raw material abundant, their use helps in reducing the level of environmental pollution and curbing the volume of waste in cities. However, one should know well the combustion process these waste before using them as fuel. Thus, Ignition behavior of combustible wastes was studied in a built fixed bed reactor. To provide a controlled thermal radiation for the ignition instant, a radiative heat flux is generated by a metal surface called a cone heater calibrated to establish the radiative heat flux density provided by a thermal resistance of 2 kW. The heat flux was 25 to 30 kWm2 over the top surface of the fuels. To validate the process, experiments with charcoal were performed varying the diameter of particles and air flow. After this, the polyethylene and human feces were analyzed. Their effects were investigated on the ignition time.
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Cherniavskyi, M. V., Ye S. Miroshnychenko, and O. Yu Provalov. "CONVERSION OF LOW AND MEDIUM POWER BOILERS FOR COMBUSTION OF SOLID FUEL BIOMASS." Energy Technologies & Resource Saving, no. 1 (March 20, 2021): 71–80. http://dx.doi.org/10.33070/etars.1.2021.08.
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The paper analyzes the existing fleet and the possibilities of replacing anthracite and natural gas boilers of low and medium capacity and substantiates that the reconstruction with conversion to biomass is appropriate for boilers with a thermal capacity of more than 5 MW. The main problem is the reduction of heat perception of furnace screens and increase of heat removal to the convective pass due to the increased specific yield of biomass combustion products. Based on the analysis of changes in the nature of combustion processes and redistribution of heat exchange in the boiler, it was determined the criteria for the possibility of converting boilers from fossil fuels to biomass with maximum use of available equipment and the most acceptable fuel for this - agricultural pellets and wood waste. Technical solutions for the reconstruction of a boiler with a dense bed with a steam capacity of 20 t/h on anthracite (24 t/h on natural gas) have been developed and calculated with transfer to burning of granules of biomass and/or gas coal without change of dimensions of a fire chamber and without loss of thermal power due to compensation of the lowered heat absorption of a fire chamber by increase of a surface of a water economizer with corresponding decrease in an air heater. Technical solutions were used during the reconstruction of 4 boilers "Babcock-Wilcox" of Khorostkiv Sugar Plant. Co-combustion of biofuel pellets with coal is implemented in the range of components share from 0 to 100%. When burning granules, underburning in the fly ash is almost absent, ash deposits on convective surfaces are self-cleaning for several hours of work on gas coal. The solutions developed allowed to solve the problem of renovation of old boilers with the expansion of their fuel base and improvement of environmental performance through the use of biomass. Bibl. 18, Fig. 3, Tab. 4.
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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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Guo, Yun, Zhi Qiang Huang, and Shun Xin Yang. "Research and Design of the Control System for Natural Gas Heater." Advanced Materials Research 842 (November 2013): 541–45. http://dx.doi.org/10.4028/www.scientific.net/amr.842.541.
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Natural gas heaters are widely used in gas-fired power plants to meet the combustion needs and to improve the combustion efficiency. For the control features and technical requirements of the natural gas heater, the computer automatic control system for natural gas heater has been designed,and realizes the temperature and liquid level real time measurement and control. The system increases significantly the control accuracy of natural gas temperature, eliminates potential unsafety and improves production efficiency.
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Mitrovic, Dejan, Branislav Stojanovic, Jelena Janevski, Marko Ignjatovic, and Goran Vuckovic. "Exergy and exergoeconomic analysis of a steam boiler." Thermal Science 22, Suppl. 5 (2018): 1601–12. http://dx.doi.org/10.2298/tsci18s5601m.
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Relying on coal as primary fuel in thermal power plants represents an unsustainable concept due to limited coal reserves and a negative environmental impact. Efficient utilization of coal reserves and a request for minimization of irreversibilities are imperative for thermal power plants operation. Numerous studies have shown that a steam boiler is a thermal power plant component with the highest irreversibility. The idea of this paper is to quantify the amounts and sources of irreversibilities within a steam boiler and its components, serving a 348.5MWe thermal power plant. Having this in mind, exergy and exergoeconomic analysis of a steam boiler is presented in this paper. Exergy destruction and exergy efficiency of all boiler components and of the boiler as a whole were calculated. Based on exergy flows and economic parameters (cost of the boiler, annual operation hours of the unit, maintenance factor, interest rate, operating period of the boiler), exergy analysis resulted in the cost of produced steam. The obtained results show that the boiler exergy efficiency is at 47.4%, with the largest exergy destruction occurring in the combustion chamber with a value of 288.07 MW (60.04%), and the smallest in the air heater with a value of 4.57 MW (0.95%). The cost of produced steam is calculated at 49,356.7 $/h by applying exergoeconomic analysis.
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Shilova, Alyona, Nikolay Bachev, and Roman Bulbovich. "INFLUENCE OF HEATING OF A GAS-AIR MIXTURE ON THE CHARACTERISTICS OF COMBUSTION OF FUEL GASES." Perm National Research Polytechnic University Aerospace Engineering Bulletin, no. 64 (2021): 83–90. http://dx.doi.org/10.15593/2224-9982/2021.64.09.
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For a stable position of the flame front in the combustion chambers of gas turbine power plants, the fresh gas-air mixture must be heated to the ignition temperature during the entire operation process. With air excess coefficients in the interval between the upper and lower concentration limits, reverse currents from the zone of developed combustion successfully cope with this task. When organizing low-temperature combustion near the lean limit, the contribution of reverse currents to heating the fresh gas-air mixture turns out to be insufficient and additional external heating of the components in special heaters with exhaust gases from the turbine is required. The temperature characteristics of the fresh gas-air mixture at the inlet to the chamber and in the zone of return currents, as well as combustion products in the developed flame zone, were obtained from the solution of the energy balance equations. The modes of low-temperature lean combustion with excess air coefficients exceeding the lower concentration limit α = 2 are considered. The calculations were carried out for two values of the ejection coefficient in the zone of reverse currents K = 0.14 and K = 0.30. A K value of 0.14 was obtained using empirical relationships. The value K = 0.30 was obtained from the condition that during stoichiometric combustion, the gas-air mixture is heated completely by reverse currents. It is shown that with an increase in the excess air ratio to ensure a stable position of the flame front, the role of external heating of components increases.
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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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Mehta, S. A., and G. A. Karim. "An Experimental Examination of the Spontaneous Ignition of Fibrous Materials in Heated Air Streams." Journal of Energy Resources Technology 110, no. 1 (March 1, 1988): 48–54. http://dx.doi.org/10.1115/1.3231360.
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The behavior of a bed of fibrous combustile material, exemplified by pure cotton (ASTM, 1982), when subjected to a controlled stream of heated air, was examined experimentally. The effects of some controlling basic physical parameters, such as sample compactness and ventilation, air stream temperature, and air stream velocity on the spontaneous ignition and combustion characteristics were established. Moreover, the observed spontaneous ignition delay time was correlated in terms of these variables. The effective activation energy during the ignition reactions was derived and shown to be dependent on the compactness of the sample.
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Stukov, M. I., A. Yu Chernavin, V. A. Kobelev, D. A. Chernavin, and K. P. Ivashinenko. "Complex of methodologies and laboratory equipment for determination of coke and slags properties in smelting zone of blast furnace." Ferrous Metallurgy. Bulletin of Scientific , Technical and Economic Information 75, no. 2 (March 10, 2019): 182–88. http://dx.doi.org/10.32339/0135-5910-2019-2-182-188.
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Information about character of burden materials behavior inside a blast furnace at its different horizons enables to increase control efficiency of BF heat running. The elaborated complex of methodologies for carbon materials and iron ore raw materials properties study enables to simulate their behavior at the horizon of iron ore materials reducing, in the viscoplastic zone, at the horizon of iron ore raw materials smelting and its interaction with coke filling. A vertical electric resistance shaft furnace with a tube carbon heater was used as a base equipment for simulation of burden behavior in the reduction zone and smelting zone, as well as for simulation of iron ore burden melt outflow through coke filling. Burden materials preparation to the experiment concluded in crushing of iron ore component followed by 3–5 mm fraction extraction and a mixing it with 3–5 mm fraction of brown coal semi-coke in relation 2:1 for further heating-reduction treatment. The heating-reduction treatment of the mixture charged in the electric furnace simulates the reducing zone and is carried out by a slow heating of the iron ore component and reducing agent mixture from 20 up to 980–1020 ºС. The methodology of determination of lump carbon materials combustibility in the highly heated air blast flow was developed for the complex of equipment based on the shaft electric resistance furnace and aimed at testing of burning process of carbon samples of technological fuels. The combustibility was determined under conditions of burnt sample heating in the temperature range from 500 up to 1500 °C with an accuracy of ±10 °С. The temperature of air blast flow (21 % vol. of oxygen at natural moisture) was set in the range from 120 up to 1200 °С and was kept with an accuracy of ±12 °С. The burnt sample mass, volume of air blast and its velocity was correlated to obtaining of complex non-dimensional Re factor (Reinolds number) more than 100, that guaranteed a reliable process running in the combustion area with no risk of transferring to gasification process. Based on GOST 26517–85 (“Iron ores, sinter and pellets”) a methodology was elaborated for determining of parameters of iron ore materials status in the viscoplastic zone. The methodology comprises heating of preliminary reduced sample of a tested iron ore material in an inert gas and determination of softening temperature and smelting end by a hard rod sinking into the material layer under external pressure action. The temperature at which the layer shrinkage reaches level of 2% during heating, was taken as the softening temperature of the iron ore material. The sinking of the rod into the material by 80% was taken as the temperature of the beginning of the material melting. The interval softening-melting was determined as the difference between melting temperature and softening temperature (at sample shrinkage by 2 %).
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Kozlov, A. A. "INCREASING EFFICIENCY OF THE DIESEL ENGINE STARTING." Russian Automobile and Highway Industry Journal 15, no. 5 (November 11, 2018): 650–59. http://dx.doi.org/10.26518/2071-7296-2018-5-650-659.
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Introduction.The paper is devoted to the investigation of the D-type diesel engines’ start-up of the B-2 type under low temperatures, especially to the influence of the fresh charge temperature on the starting characteristics of the diesel engines. The Russian Federation is located in climatic zones with predominance of low ambient air temperatures and under extreme conditions. However, such situation is not adequately studied in scientific literature.The main problem is in the search for rational values of the temperature of the fresh charge at the beginning of the compression stroke. The increase of such temperature leads to the decrease in the oxygen mass, and to the decrease to an insufficient temperature at the end of the compression stroke and, as a result, it would not provide ignition. Therefore, the aim of the research is to substantiate the rational values of the fresh charge temperature and further practical implementation of these values at modern BTWT facilities.Materials and methods.The author uses standard theoretical and theoretical methods based on widely approved dependences of the piston internal combustion engines’ theory, gas dynamics and thermodynamics, which have been refined taking into account the features of the diesel engine start. Results. As a result, the author determines rational values of the fresh charge temperature, makes the analysis of the pre-launch preparation and facilitating of the D-type diesel engines’ start-up and demonstrates the method of increasing and further stabilizing of the temperature of the inlet charge at modern BTWT facilities.Discussion and conclusion.The research confirms the rational values of the fresh charge temperature, by using of which the diesel has the best starting characteristics. The author also proposes a technical solution for values’ realization by using a vortex induction heater.
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Hao, Shimeng, Yuejia Xu, Changming Yu, Yehao Song, and Zhenghao Lin. "Experimental Investigation of the Surface Temperature Distribution and Thermal Performance of an Intermittent Combustion Chinese Heated Wall." Advances in Materials Science and Engineering 2018 (September 25, 2018): 1–13. http://dx.doi.org/10.1155/2018/3457950.
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Chinese heated walls represent a traditional space heating technique that is still widely used in vernacular houses in northern China. Such walls efficiently recover gas heat from heating stoves and reduce users' exposures to indoor air pollution. This experimental study proposed a heat recovery system composed of a heated wall and fireplace. Test rooms were set up to evaluate the surface temperature distribution and thermal performance of the heated wall in response to several combustion patterns. The results show that an intermittent combustion heated wall heated only by a stove used for cooking can produce a relatively more comfortable indoor environment without extra energy consumption. In this research, indoor air temperature was increased by 3.3 to 4.0°C over the control room. The temperature distribution of the heated wall's surface was nonuniform, with a temperature range of 116.03°C. It was also found that the combustion pattern had a major impact on the initial and peak temperatures of the wall body's surface during combustion.
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Xiang, Yang, Xiao Min Jiang, and Min Ye Chen. "New Biogas Heater Burner 3D Virtual Design." Advanced Materials Research 724-725 (August 2013): 274–78. http://dx.doi.org/10.4028/www.scientific.net/amr.724-725.274.
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To establish the biogas heater burner 3D virtual design platform with the software of Solidworks, a new type of biogas burner is developed using the 3D virtual design platform ,including base 1, nozzle device 2, venturi 3, premixing device 4 and burner nozzle 5, elaborated on the structure characteristics of key component nozzle device how to realize the biogas source of instability, pressure and flow fluctuation, can still achieve full combustion, stable combustion, high combustion value objective.
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Karakash, Y., L. Gres, and O. Gupalo. "Research of gas-dynamic processes of motion of combustion products of blast-air heaters." Theory and practice of metallurgy, no. 6 (November 20, 2018): 57–61. http://dx.doi.org/10.34185/tpm.6.2018.07.
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The article deals with the methods of physical modeling of gas-dynamic processes and the calculation of aerodynamic resistance in the motion of combustion products on the exhaust system. The analysis of echoing methods for increasing the diversion of combustion products of hot stoves has been carried out and their main disadvantages have been identified. The basic principles of creation of mathematical models of flue gas flow on an exhaust system are considered and an estimation of their adaptability to the really conditions. The main reasons for the reduction of traction in the exhaust system of the blast-furnace shop of Dneprovsky DMZ are revealed. The research of the state of refractory lining was conducted and the main reasons of a short period of its work were revealed. The ejection and injection phenomena on the basis of which several ways of increasing traction in the chimney tract are considered. Investigations of the level of pressure of combustion products at the exit from the combustion chamber on the existing air heaters have been carried out. The influence of taking blast furnace on draft through air heaters on the duration of service life of refractories of exhaust system and the degree of mixing of combustion products during tangential feeding to common forests is revealed. The calculation of pressure losses in the smoke boron under the conditions of the blast-furnace shop of Dneprovsky DMZ is carried out. Considered ways to increase the value of traction for effective smoke removal from blast air heaters. During the experiments, the distribution of flows between the ejector and around the nozzle was detected. Conclusions are made on the necessity of using some methods for increasing traction in smoke boron and the correspondence of some coefficients of local resistance to experimental data. It is suggested to conduct further physical experiments to specify the coefficients of local resistance.
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Karim, G. A., A. Hanafi, and S. A. Mehta. "Volatilization and Ignition of Oil Sand Samples During Intermittent Exposure to Hot Low-Velocity Air Streams." Journal of Energy Resources Technology 111, no. 2 (June 1, 1989): 104–9. http://dx.doi.org/10.1115/1.3231404.
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The behavior of small oil sand samples was monitored experimentally when subjected repeatedly to low-velocity heated air streams, with either prompt quenching or slow cooling of the samples to their initial temperatures between these exposures. The stream temperature was either in the range of 300°C to 500°C in air or at higher temperatures of up to 760°C, while being exposed to the products of combustion of very lean hydrogen-air mixtures. This was done in relation to understanding better the associated processes in some in-situ recovery trials where stoppage of the combustion front and/or the flow of the injected fluids can occur. A variety of multi-exposure-cooling schemes was considered and their effects on the extent of volatilization and ignition established. Comparison to the corresponding behavior of similar samples under uninterrupted exposure to the heated streams was made throughout.
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Ren, Tian Qi, Kai Fang, and Shi Hong Zhang. "Study on Influence to the Ceramic Glaze Color of Environmental-Friendly Pottery Brick by Low-Carbon Catalytic Combustion Furnace of Natural Gas." Advanced Materials Research 1088 (February 2015): 706–10. http://dx.doi.org/10.4028/www.scientific.net/amr.1088.706.
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This experiment consists of two parts. On the one hand is about the concentration of Variation of exhaust gas when heated potteries .On the other hand is about the compared between the potteries (Tang Dynasty) heated by natural gas catalytic combustion furnace and the traditional firing of the glaze. The potteries fired by catalytic combustion furnace could be used for decorating are not only more fine and glossy than the traditional, but also more translucent. Therefore, the potteries made by catalytic combustion furnace will be applied in decoration industries, such as decorative murals.