Journal articles: 'Coal-fired furnaces'

1

Wehrmeyer, Joseph A., David E. Boll, and Richard Smith. "Emission Spectroscopy for Coal-Fired Cyclone Furnace Diagnostics." Applied Spectroscopy 57, no. 8 (August 2003): 1020–26. http://dx.doi.org/10.1366/000370203322258995.

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Using a spectrograph and charge-coupled device (CCD) camera, ultraviolet and visible light emission spectra were obtained from a coal-burning electric utility's cyclone furnaces operating at either fuel-rich or fuel-lean conditions. The aim of this effort is to identify light emission signals that can be related to a cyclone furnace's operating condition in order to adjust its air/fuel ratio to minimize pollutant production. Emission spectra at the burner and outlet ends of cyclone furnaces were obtained. Spectra from all cyclone burners show emission lines for the trace elements Li, Na, K, and Rb, as well as the molecular species OH and CaOH. The Ca emission line is detected at the burner end of both the fuel-rich and fuel-lean cyclone furnaces but is not detected at the outlet ends of either furnace type. Along with the disappearance of Ca is a concomitant increase in the CaOH signal at the outlet end of both types of furnaces. The OH signal strength is in general stronger when viewing at the burner end rather than the exhaust end of both the fuel-rich and fuel-lean cyclone furnaces, probably due to high, non-equilibrium amounts of OH present inside the furnace. Only one molecular species was detected that could be used as a measure of air/fuel ratio: MgOH. It was detected at the burner end of fuel-rich cyclone furnaces but not detected in fuel-lean cyclone furnaces. More direct markers of air/fuel ratio, such as CO and O2 emission, were not detected, probably due to the generally weak nature of molecular emission relative to ambient blackbody emission present in the cyclone furnaces, even at ultraviolet wavelengths.

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von Bohnstein, Maximilian, Coskun Yildiz, Lorenz Frigge, Jochen Ströhle, and Bernd Epple. "Simulation Study of the Formation of Corrosive Gases in Coal Combustion in an Entrained Flow Reactor." Energies 13, no. 17 (September 1, 2020): 4523. http://dx.doi.org/10.3390/en13174523.

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Gaseous sulfur species play a major role in high temperature corrosion of pulverized coal fired furnaces. The prediction of sulfur species concentrations by 3D-Computational Fluid Dynamics (CFD) simulation allows the identification of furnace wall regions that are exposed to corrosive gases, so that countermeasures against corrosion can be applied. In the present work, a model for the release of sulfur and chlorine species during coal combustion is presented. The model is based on the mineral matter transformation of sulfur and chlorine bearing minerals under coal combustion conditions. The model is appended to a detailed reaction mechanism for gaseous sulfur and chlorine species and hydrocarbon related reactions, as well as a global three-step mechanism for coal devolatilization, char combustion, and char gasification. Experiments in an entrained flow were carried out to validate the developed model. Three-dimensional numerical simulations of an entrained flow reactor were performed by CFD using the developed model. Calculated concentrations of SO2, H2S, COS, and HCl showed good agreement with the measurements. Hence, the developed model can be regarded as a reliable method for the prediction of corrosive sulfur and chlorine species in coal fired furnaces. Further improvement is needed in the prediction of some minor trace species.

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Walia, Garvit, and Cameron Stanley. "Feasibility Study On the Conversion of Coal-Fired Furnaces to Biomass-Fired Furnaces in Vietnam." International Journal of Scientific and Research Publications (IJSRP) 9, no. 2 (February 6, 2019): p8614. http://dx.doi.org/10.29322/ijsrp.9.02.2019.p8614.

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Wang, Xuebin, Zia Ur Rahman, Zhaomin Lv, Yiming Zhu, Renhui Ruan, Shuanghui Deng, Lan Zhang, and Houzhang Tan. "Experimental Study and Design of Biomass Co-Firing in a Full-Scale Coal-Fired Furnace with Storage Pulverizing System." Agronomy 11, no. 4 (April 20, 2021): 810. http://dx.doi.org/10.3390/agronomy11040810.

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Co-firing coal and biomass in existing power plants facilitates influential advancement in the use of renewable energy resources and carbon emissions reduction. Biomass is intended as a CO2-zero net emission because, during its rise, it uses the same fraction of CO2 from the air as that released during its combustion. In addition, the content of nitrogen and sulfur in biomass is lower than in coal. Therefore, the emissions of NOx and SOx can be minimized by co-firing it with coal. In general, the effect of biomass direct co-firing on safety, pulverizing system performance, furnace efficiency, and NOx emission in full-scale furnaces is rarely studied. In this study, biomass direct co-firing was carried out in a 55 MW tangentially fired pulverized coal furnace. The effects of biomass co-firing on safety, the performance of the pulverizing system, furnace efficiency, and pollutant emissions (unburned carbon and NOx) are studied. The results show that the blending of biomass fuel with less than 20% of coal has no issue with respect to auto-ignition and safety. The performance of the pulverizing system is affected up to a certain limit due to the difficulty of grinding the biomass particles into required fineness. The biomass co-firing up to 20% is feasible, but greater than this percentage will severely affect the furnace efficiency. The co-firing of biomass enhanced the NOx reduction significantly and further improved the performance of the SNCR process. This study could provide guidance for the application of biomass co-firing in industrial furnaces.

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Musa, Amir A. B., Xiong Wei Zeng, Qing Yan Fang, and Huai Chun Zhou. "Numerical Simulation on Improving NO_x Reduction Efficiency of SNCR by Regulating the 3-D Temperature Field in a Furnace." Advanced Materials Research 807-809 (September 2013): 1505–13. http://dx.doi.org/10.4028/www.scientific.net/amr.807-809.1505.

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The optimum temperature within the reagent injection zone is between 900 and 1150°C for the NOX reduction by SNCR (selective non-catalytic reduction) in coal-fired utility boiler furnaces. As the load and the fuel property changes, the temperature within the reagent injection zone will bias from the optimum range, which will reduces significantly the de-NOX efficiency, and consequently the applicability of SNCR technology. An idea to improve the NOX reduction efficiency of SNCR by regulating the 3-D temperature field in a furnace is proposed in this paper. In order to study the new method, Computational fluid dynamics (CFD) model of a 200 MW multi-fuel tangentially fired boiler have been developed using Fluent 6.3.26 to investigate the three-fuel combustion system of coal, blast furnace gas (BFG), and coke oven gas (COG) with an eddy-dissipation model for simulating the gas-phase combustion, and to examine the NOX reduction by SNCR using urea-water solution. The current CFD models have been validated by the experimental data obtained from the boiler for case study. The results show that, with the improved coal and air feed method, average residence time of coal particles increases 0.3s, burnout degree of pulverized coal increases 2%, the average temperature at the furnace nose decreases 61K from 1496K to 1435K, the NO emission at the exit (without SNCR) decreases 58 ppm from 528 to 470 ppm, the SNCR NO removal efficiency increases 10% from 36.1 to 46.1%. The numerical simulation results show that this combustion adjustment method based on 3-D temperature field reconstruction measuring system in a 200 MW multi-fuel tangentially fired utility boiler co-firing pulverized coal with BFG and COG is timely and effective to maintain the temperature of reagent injection zone at optimum temperature range and high NOX removal efficiency of SNCR.

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Gurusingam, Pogganeswaran, Firas Basim Ismail, and Taneshwaren Sundaram. "Operating Parameter Optimization using DOE Method to Reduce Unburned Carbon of Fly Ash for Tangential Fired Subcritical Coal Fired Power Plant." MATEC Web of Conferences 225 (2018): 05008. http://dx.doi.org/10.1051/matecconf/201822505008.

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As electric demand increasing due to rapid economic growth, most developing country are sourcing for cheap fuel and low maintenance power plant which coal fired power plant become the more preferable plant. The cheap and abundant coal resources have played a major factor for coal power plant selection compare to other type of power plant. Although this plant type has low maintenance and operating cost but its emission of by product has a great effect on daily plant operation and environment. The one of the major emission was unburned carbon which by product of incomplete combustion where remaining of coal that unburned exits the furnaces with ash. Presence of higher percentage of unburned carbon indicates the low efficiency of furnace combustion and this directly affects financial status of the power plant operators. This condition causes severe damages on the boiler tube by formation of slagging and clinkering which reduces heat transfer and efficiency of the furnace. Current method proved to be more time consuming and plant operator facing difficulty to reduce unburned carbon in real time. As a solution for this problem, a best parameter was predicted to achieve low percentage of unburned carbon.

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Belosevic, Srdjan, Ivan Tomanovic, Nenad Crnomarkovic, and Aleksandar Milicevic. "Modeling of pulverized coal combustion for in-furnace NOx reduction and flame control." Thermal Science 21, suppl. 3 (2017): 597–615. http://dx.doi.org/10.2298/tsci160604186b.

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A cost-effective reduction of NOx emission from utility boilers firing pulverized coal can be achieved by means of combustion modifications in the furnace. It is also essential to provide the pulverized coal diffusion flame control. Mathematical modeling is regularly used for analysis and optimization of complex turbulent reactive flows and mutually dependent processes in coal combustion furnaces. In the numerical study, predictions were performed by an in-house developed comprehensive three-dimensional differential model of flow, combustion and heat/mass transfer with submodel of the fuel- and thermal-NO formation/ destruction reactions. Influence of various operating conditions in the case-study utility boiler tangentially fired furnace, such as distribution of both the fuel and the combustion air over the burners and tiers, fuel-bound nitrogen content and grinding fineness of coal were investigated individually and in combination. Mechanisms of NO formation and depletion were found to be strongly affected by flow, temperature and gas mixture components concentration fields. Proper modifications of combustion process can provide more than 30% of the NOx emission abatement, approaching the corresponding emission limits, with simultaneous control of the flame geometry and position within the furnace. This kind of complex numerical experiments provides conditions for improvements of the power plant furnaces exploitation, with respect to high efficiency, operation flexibility and low emission.

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Fan, J. R., X. D. Zha, and K. F. Cen. "Computerized Analysis of Low NOxW-Shaped Coal-Fired Furnaces." Energy & Fuels 15, no. 4 (July 2001): 776–82. http://dx.doi.org/10.1021/ef0000173.

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9

Wang, Fan, Yu Liu, Gang Tian, Hong Chang Wang, Fan Zhang, Chang Zhu Lu, and Tao Yue. "Study on Low-NOx Combustion Technology for Coal-Fired Industrial Boilers." Applied Mechanics and Materials 341-342 (July 2013): 1239–44. http://dx.doi.org/10.4028/www.scientific.net/amm.341-342.1239.

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Based on the analysis of combustion conditions of the experimental grate-fired furnaces with a capacity of 2t/h, a low-NOx combustion transformation program was proposed. The effects of influencing factors including fuel staged combustion, air staged combustion and circulating flue gas on NOx emissions were investigated. The results show that when air-staged combustion based on separate room air distribution and fuel staged combustion, NOx emissions decreased from 260-359 mg/Nm3to 137-182 mg/Nm3. And when circulating flue gas rate reached 10-15%, NOx emissions decreased 3-5%. These results indicate that the NOx concentration in the flue gas of the grate-fired furnaces with low-NOx combustion technology was below 200 mg/Nm3, which has great application prospects.

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10

Askarova A.S., Bolegenova S.A., Safarik P., Bolegenova S.A., Maximov V.Yu, Beketayeva M.T., and Nugymanova A.O. "MODERN COMPUTING EXPERIMENTS ON PULVERIZED COAL COMBUSTION PROCESSES IN BOILER FURNACES." PHYSICO-MATHEMATICAL SERIES, no. 6 (December 15, 2018): 5–14. http://dx.doi.org/10.32014/2018.2518-1726.11.

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The aim of the work is to create new computer technologies for 3D modeling of heat and mass transfer processes in high-temperature physico-chemical-reactive environments that will allow to determine the aerodynamics of the flow, heat and mass transfer characteristics of technological processes occurring in the combustion chambers in the operating coal TPP RK. The novelty of the research lies in the use of the latest information technologies of 3D modeling, which will allow project participants to obtain new data on the complex processes of heat and mass transfer during the burning of pulverized coal in real combustion chambers operating in the CHP of RK. Numerical simulation, including thermodynamic, kinetic and three-dimensional computer simulation of heat and mass transfer processes when burning low-grade fuel, will allow finding optimal conditions for setting adequate physical, mathematical and chemical models of the technological process of combustion, as well as conduct a comprehensive study and thereby develop ways to optimize the process of ignition, gasification and burning high ash coals. The proposed methods of computer simulation are new and technically feasible when burning all types of coal used in pulverized coal-fired power plants around the world. The developed technologies will allow replacing or eliminating the conduct of expensive and labor-consuming natural experiments on coal-fired power plants.

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11

Sundaram, Taneshwaren, Firas Basim Ismail, and Pogganeswaren Gurusingam. "Soot Blowing Operation Optimization Using PSO Method by Studying Behaviour of Operating Parameter in Sub Critical Coal Fired Power Plant." MATEC Web of Conferences 225 (2018): 01005. http://dx.doi.org/10.1051/matecconf/201822501005.

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Coal, natural gas and fuel-oil are three major fossil fuels sources are vastly used in electrical power generation sector in Malaysia. In a coal fired power plant, the major byproducts resulting from coal combustion inside boiler is soot, ash and NOx emissions. Boiler fouling and slagging are common problems that leads reduces heat transfer rate in furnace and boiler efficiency. This happens when soot and ash is formed and deposited along the boiler tubes, furnaces and heaters. Hence, soot blowing operation is used to blow off steam in affected areas of boilers as a cleaning mechanism. However, current soot blowing operation is practiced through operator’s visual inspection of slagging or fouling rate in furnace. This leads to inefficient soot blowing operation that effects the plant’s operating and maintenance cost. Thus, by studying behavior of operating parameters, soot blowing operation can be optimized to reduce unnecessary soot blowing operation in power plant.

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12

Belosevic, Srdjan, Ivan Tomanovic, Nenad Crnomarkovic, Aleksandar Milicevic, and Dragan Tucakovic. "Modeling and optimization of processes for clean and efficient pulverized coal combustion in utility boilers." Thermal Science 20, suppl. 1 (2016): 183–96. http://dx.doi.org/10.2298/tsci150604223b.

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Pulverized coal-fired power plants should provide higher efficiency of energy conversion, flexibility in terms of boiler loads and fuel characteristics and emission reduction of pollutants like nitrogen oxides. Modification of combustion process is a cost-effective technology for NOx control. For optimization of complex processes, such as turbulent reactive flow in coal-fired furnaces, mathematical modeling is regularly used. The NOx emission reduction by combustion modifications in the 350 MWe Kostolac B boiler furnace, tangentially fired by pulverized Serbian lignite, is investigated in the paper. Numerical experiments were done by an in-house developed three-dimensional differential comprehensive combustion code, with fuel- and thermal-NO formation/destruction reactions model. The code was developed to be easily used by engineering staff for process analysis in boiler units. A broad range of operating conditions was examined, such as fuel and preheated air distribution over the burners and tiers, operation mode of the burners, grinding fineness and quality of coal, boiler loads, cold air ingress, recirculation of flue gases, water-walls ash deposition and combined effect of different parameters. The predictions show that the NOx emission reduction of up to 30% can be achieved by a proper combustion organization in the case-study furnace, with the flame position control. Impact of combustion modifications on the boiler operation was evaluated by the boiler thermal calculations suggesting that the facility was to be controlled within narrow limits of operation parameters. Such a complex approach to pollutants control enables evaluating alternative solutions to achieve efficient and low emission operation of utility boiler units.

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Gupta, R. P., and T. F. Wall. "The optical properties of fly ash in coal fired furnaces." Combustion and Flame 61, no. 2 (August 1985): 145–51. http://dx.doi.org/10.1016/0010-2180(85)90160-9.

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Dakic, Dragoljub, Srdjan Belosevic, Rastko Mladenovic, Milijana Paprika, Dejan Djurovic, Aleksandar Eric, Mirko Komatina, Bosko Grbic, and Nenad Radic. "Reduction of carbon monoxide emission from a solid-fuel thermo-accumulation furnace." Thermal Science 10, no. 4 (2006): 107–19. http://dx.doi.org/10.2298/tsci0604107d.

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Many households in Serbia, using electric thermo-accumulation furnaces for heating, have been forced to find an alternative solution, due to a significant increase in electricity prices during the last decade. A possible solution is replacing electric heating appliances with the solid fuel-fired ones. A prototype of a new concept of thermo-accumulation solid fuel-fired furnace has been developed to meet these growing needs, providing electricity saving together with considerable environmental benefits. Two strategies for reduction of carbon monoxide emission are examined in the paper: application of Pt/Al2O3 catalyst, in the form of 3 ? 0.3 mm spheres, providing further combustion of flue gases within the furnace, as well as an additional emission reduction by means of the air excess control. Experimental investigations of the catalyst influence on the conversion of carbon monoxide have been done for different operation regimes and positions of the catalyst. The paper presents selected results regarding carbon monoxide emission during wood and coal combustion. Investigations suggest a considerable effect of the catalyst and a strong influence of the catalyst position within the furnace to carbon monoxide emission reduction. In addition, experimental tests have been conducted to asses the effect of the air excess control in the furnace on carbon monoxide emission. The amount of combustion air, the flue gas flow rate, and the fuel feeding regime have been adjusted in order to keep the flue gas oxygen content in a relatively narrow range, thus obtaining controlled combustion conditions and lower carbon monoxide emission. In this way, the furnace has been made able to respond to the changes in heating needs, fuel quality and other parameters, which is advantageous in comparison with similar solid-fuel fired furnaces. .

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Tian, Zhong Jun, Shi Ping Jin, and Yu Ming Liang. "Investigation of the System Coupling Regenerative Heat Exchange and Selective Catalytic Reduction for Heat Exchange and NO_x Removal." Advanced Materials Research 955-959 (June 2014): 2087–92. http://dx.doi.org/10.4028/www.scientific.net/amr.955-959.2087.

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In conjunction with theoretical heat exchange model, experimental investigations have been conducted for a coupled system of Selective Catalytic Reduction (SCR) and Regenerative Heat Exchange (RHE), to reduce nitrogen oxides (NOx) from coal-fired boilers and High Temperature Air Combustion (HiTAC) furnaces. Results indicate there is no effect of catalysis reactions on heat transfer; catalysts serve the function of heating elements. The outlet NO concentration periodically decreased in an almost linear fashion. NO conversion: i) rose slowly with a longer switching time; and ii) reached the peak value of temperature with a delay compared with the steady state. The coupled system requires less space and hence is a suitable option for SCR renovations in coal-fired power plants.

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Zhu, Bo, Bichen Shang, Xiao Guo, Chao Wu, Xiaoqiang Chen, and Lingling Zhao. "Study on Combustion Characteristics and NOx Formation in 600 MW Coal-Fired Boiler Based on Numerical Simulation." Energies 16, no. 1 (December 26, 2022): 262. http://dx.doi.org/10.3390/en16010262.

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The variations in the boiler operation conditions have a great effect on the combustion characteristics and the pollutant formation in furnaces. This work aims to investigate the effects of operational parameters on NOx formation and its distribution in furnaces using the numerical simulation method to obtain the optimum control strategy for reducing NOx emissions. The numerical simulation models of pulverized coal combustion in furnaces involving flow, heat transfer, combustion and NOx formation are established. Taking a 600 MW supercritical opposed firing pulverized coal boiler as the study object, a full-scale three-dimensional physical model of the boiler is constructed with Gambit software. On this basis, the pulverized coal combustion and the NOx formation under various boiler loads are numerically simulated using the software of Ansys Fluent 2021R1, and the accuracy and the reliability of the models established are verified by comparing the simulation data with the field test data. According to the combustion numerical simulation of 128 groups of operating conditions, the effects of boiler load, the air rate and the air temperature on combustion and NOx formation have been emphatically investigated. The simulation results indicate that the formation of NOx and the NOx concentration distribution are mainly affected by the oxygen concentration and the temperature in the furnace. Especially, the effects of the variation in the excess air coefficient, the over-fire air (OFA) ratio, the primary air ratio and the internal secondary air ratio on NOx concentration distribution vary greatly. When the air temperature increases the overall NOx concentration in the furnace increases, and the influence of the secondary air temperature and the OFA temperature is greater than that of the primary air temperature. Large amounts of simulation data are a necessary data source for further study on the NOx prediction model at the economizer outlet, which can improve the prediction ability and the generalization ability of the NOx prediction model.

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Yao, Jie. "Based on Image Procession to Measure Flame Emission Characteristic and Radioactive Properties." Applied Mechanics and Materials 214 (November 2012): 237–43. http://dx.doi.org/10.4028/www.scientific.net/amm.214.237.

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radioactive properties are hard to be given exactly by the existing methods. In this paper, multiple color image detectors were used to capture approximately red, green, and blue monochromatic radioactive intensity images in the visible wavelength region, and the flame emissive and the radioactive properties of the particulate media in three pulverized-coal-fired boiler furnaces were got from the flame images.

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Wzorek, Małgorzata. "Evaluating the Potential for Combustion of Biofuels in Grate Furnaces." Energies 13, no. 8 (April 15, 2020): 1951. http://dx.doi.org/10.3390/en13081951.

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The paper assesses the impact of combustion of biofuels produced based on municipal sewage sludge in stoker-fired boilers on the amount of pollutant emissions and examines the tendency of ash deposition of biofuels formed during the combustion process. The combustion tests were performed in a laboratory system enabling simulation of a combustion process present in stoker-fired boilers. The study was conducted for three types of biofuels; i.e., fuel from sewage sludge and coal slime (PBS fuel), sewage sludge and meat and bone meal (PBM fuel) and fuel based on sewage sludge and sawdust (PBT) with particle size of 35 mm and 15 mm. This paper describes and compares the combustion process of biofuels with different granulation and composition and presents the results of changes in emission values of NOx, SO2, CO, and CO2. The emission results were compared with the corresponding results obtained during combustion of hard coal. The results showed that biofuels with lower particle sizes were ignited faster and the shortest ignition time is achieved for fuel based on sewage sludge and coal slime-PBS fuel. Also, the highest NO and SO2 emissions were obtained for PBS fuel. During the combustion of fuel based on sewage sludge and meat and bone meal (PBM), on the other hand, the highest CO2 emissions were observed for both granulations. Biofuels from sludge show a combustion process that is different compared to the one for hard coal. The problems of ash fouling, slagging, and deposition during biofuels combustion were also identified. The tendency for ash slagging and fouling is observed, especially for fuel from sewage sludge and meat and bone meal (PBM) and fuel based on sewage sludge and sawdust (PBT) ashes which consist of meat and bone meal and sawdust which is typical for biomass combustion.

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Fan, Jianren, Ligeng Qian, Yinliang Ma, Ping Sun, and Kefa Cen. "Computational modeling of pulverized coal combustion processes in tangentially fired furnaces." Chemical Engineering Journal 81, no. 1-3 (January 2001): 261–69. http://dx.doi.org/10.1016/s1385-8947(00)00212-6.

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Green, A., and M. Waite. "A Validation Strategy For The CFD Modelling Of Coal-Fired Equipment." NAFEMS International Journal of CFD Case Studies 4 (January 2004): 51–62. http://dx.doi.org/10.59972/r7656ms9.

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The chain-grate stoker is a well-established lump coal firing method for furnaces. Its current use for coal in the UK and USA is limited to old plant but is extensive in Eastern Europe, India and China. Problems associated with its use stem from gaseous and fly ash pollution. The mathematical modelling of such a system was undertaken as part of an initiative funded by European Coal and Steel Consortium. The objective was to produce a model suitable for use by, e.g. plant manufacturers, to show the effect of design modifications. This would be especially for efficiency improvement and pollution reduction. The main experimental work was carried out using the chain grate stoker rig facilities of CRE, Cheltenham...

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Fan, J. R., X. D. Zha, and K. F. Cen. "Computerized Analysis of Low NOxW-Shaped Coal-Fired Furnaces.2001,15, 776−782." Energy & Fuels 18, no. 3 (May 2004): 896. http://dx.doi.org/10.1021/ef040028m.

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Wall, T. F., S. P. Bhattacharya, D. K. Zhang, R. P. Gupta, and X. He. "The properties and thermal effects of ash deposits in coal-fired furnaces." Progress in Energy and Combustion Science 19, no. 6 (January 1993): 487–504. http://dx.doi.org/10.1016/0360-1285(93)90002-v.

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Guo, Li, Haofan Wang, Xian Li, Xiangxi Wang, Nanxi Bie, Bin Yao, Weijun Zhen, Jian Li, Chun Lou, and Hong Yao. "Investigation of Slagging Condition in a Zhundong Coal-Fired Boiler via In Situ Optical Measurement of Gaseous Sodium." Sensors 24, no. 2 (January 12, 2024): 488. http://dx.doi.org/10.3390/s24020488.

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In this study, a portable spectral analysis instrument based on spontaneous emission spectroscopy (SES) was developed for the in situ, non-intrusive, and quantitative measurement of gaseous Na inside ZD coal-fired boilers, which is mainly applied for predicting slagging in furnaces. This technology is needed urgently because the problem of fouling and slagging caused by high alkali metals in ZD coal restricts the rational utilization of this coal. The relative extended uncertainty for the measurement of gaseous Na concentration is Urel = 10%, k = 2, which indicates that measurement data are reliable under working conditions. It was found that there is a clear linear relationship between the concentration of gaseous Na and fouling in high-alkali coal boilers. Therefore, a fast and efficient method for predicting the slagging and fouling of high-alkali coal boilers can be established by using this in situ online real-time optical measurement.

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Ongar, Bulbul, Hristo Beloev, Iliya Iliev, Assem Ibrasheva, and Anara Yegzekova. "Numerical simulation of nitrogen oxide formation in dust furnaces." EUREKA: Physics and Engineering, no. 1 (January 10, 2022): 23–33. http://dx.doi.org/10.21303/2461-4262.2022.002102.

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Even though natural sources of air pollution account for over 50 % of sulphur compounds, 93 % of nitrogen oxide which are the most dangerous artificial anthropogenic sources of air pollution and primarily associated with the combustion of fossil fuel. Coal-fired thermal power plants and industrial fuel-burning plants that emit large quantities of nitrogen oxides (NО and NО2), solids (ash, dust, soot), as well as carbon oxides, aldehydes, organic acids into the atmosphere pollute the environment in majority. In the present work, a mathematical model and a scheme for calculating the formation of nitrogen oxide has been developed. Also, the dependence of the rate of release of fuel nitrogen from coal particles at the initial stage of gasification and content of volatiles has been obtained. The main regularities of the formation of NOx at the initial section of the flame in the ignition zone of the swirl burner flame during the combustion of Ekibastuz coal have been revealed. Modern environmental requirements for the modernization of existing and the creation of new heat and power facilities determine the exceptional relevance of the development of effective methods and constructions to reduce emissions of nitrogen oxides, sulfur oxides and ash to 200, 300, and 100 mg/nm3 at a=1.4. The dust consumption in all experiments was kept constant and amounted to 0.042 g/s, as well as with the results of calculating the thermal decomposition of the Ekibastuz coal dust, the recombination of atomic nitrogen into nitrogen molecules, and the kinetics of the formation of fuel nitric oxide. It was found that despite the presence of oxygen in Ekibastuz coal for gases Odaf=11.8 % in an inert atmosphere, nitrogen oxides are not formed

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Fukayama, Yukio, and Takashi Kuwabara. "An On-line Identification Method for the Slagging Factor in Coal-Fired Furnaces." Proceedings of the ISCIE International Symposium on Stochastic Systems Theory and its Applications 1997 (May 5, 1997): 25–30. http://dx.doi.org/10.5687/sss.1997.25.

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Crnomarkovic, Nenad, Srdjan Belosevic, Stevan Nemoda, Ivan Tomanovic, Aleksandar Milicevic, Andrijana Stojanovic, and Goran Stupar. "Determination of the sootblower activation moment for biomass co-firing in a pulverized coal furnace." Thermal Science, no. 00 (2022): 149. http://dx.doi.org/10.2298/tsci220516149c.

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The pulverized coal-fired furnaces are expected to use co-firing with biomass for environmental reasons. Although the non-uniform ash deposits are formed on the furnace walls, the uniform deposits could be used for the analysis of the furnace operation. The objective of this investigation was determination of the uniform deposit thickness, used as a criterion for prediction of the sootblower activation moment in coal-biomass co-firing. The investigation comprised numerical simulations for uniform and non-uniform deposits to find the relative differences for the selected variables that were important for the sootblower activation: the mean wall fluxes and flame temperatures. The local thicknesses of the non-uniform deposits were determined by the gamma distribution for several mean and standard deviation values using the inversion method. The thicknesses of the uniform deposits were considered among the measures of central tendency: mode, mean, and median, of the non-uniform deposits. The mean was expected to provide the smallest relative differences, while the mode was excluded from further consideration after analysis of its values. The median was found to be better choice than the mean, as it provided smaller relative differences of the selected variables for the thick deposits, which were important for the sootblower activation. The method based on comparison of the uniform deposits for coal firing and those for the co-firing with biomass was proposed for the prediction of the sootblower activation moment. The method can be used for the selection of the operational regimes for coal-biomass co-firing.

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Han, Xiaohai, Xiaolin Wei, Uwe Schnell, and Klaus R. G. Hein. "Detailed modeling of hybrid reburn/SNCR processes for NOX reduction in coal-fired furnaces." Combustion and Flame 132, no. 3 (February 2003): 374–86. http://dx.doi.org/10.1016/s0010-2180(02)00481-9.

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SHIMOGORI, Miki, and Koji KURAMASHI. "Basic idea for the prediction of burner minimum loads for different coal-fired furnaces." Proceedings of Conference of Chugoku-Shikoku Branch 2002 (2002): 83–84. http://dx.doi.org/10.1299/jsmecs.2002.83.

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Ratafia-Brown, Jay A. "Overview of trace element partitioning in flames and furnaces of utility coal-fired boilers." Fuel Processing Technology 39, no. 1-3 (August 1994): 139–57. http://dx.doi.org/10.1016/0378-3820(94)90177-5.

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30

Jing, Xuehui, Yang Pu, Zhaoyu Li, Quanli Tang, Bin Yao, Peifang Fu, Chun Lou, and Mooktzeng Lim. "Experimental Investigation of Gaseous Sodium Release in Slag-Tapping Coal-Fired Furnaces by Spontaneous Emission Spectroscopy." Energies 15, no. 11 (June 6, 2022): 4165. http://dx.doi.org/10.3390/en15114165.

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High-alkali coal is rich in alkali metals, which can cause serious effects such as slagging and corrosion on the heating surface during combustion and utilization. A portable spectral system was utilized to simultaneously measure gaseous Na concentration and temperature in a 20 kW slag-tapping combustor and a slagging boiler furnace of a 300 MW power generation unit by flame spontaneous emission spectroscopy (FES) for simultaneous measuring. The result shows that both ZD-FK and ZD-HSQ (Fukang coal and Hongshaquan coal, Xinjiang Zhundong high-alkali coal) combustion flame temperatures are around 1400 °C at the outlet of the cyclone burner while the latter is slightly higher. The sodium concentration in the gas phase increases with the rising of the initial combustion temperature and unit load for one kind of coal, and the level of sodium concentration has a strong correlation with the Na content for different coal. Most of the sodium in the high temperature zone of the furnace exists in the form of gas phase, and more sodium migrates to fly ash. Combined with the analysis of fly ash and liquid slag samples, a closed-loop analysis of the Na migration path could be established.

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31

Jing, Xuehui, Yang Pu, Zhaoyu Li, Quanli Tang, Bin Yao, Peifang Fu, Chun Lou, and Mooktzeng Lim. "Experimental Investigation of Gaseous Sodium Release in Slag-Tapping Coal-Fired Furnaces by Spontaneous Emission Spectroscopy." Energies 15, no. 11 (June 6, 2022): 4165. http://dx.doi.org/10.3390/en15114165.

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High-alkali coal is rich in alkali metals, which can cause serious effects such as slagging and corrosion on the heating surface during combustion and utilization. A portable spectral system was utilized to simultaneously measure gaseous Na concentration and temperature in a 20 kW slag-tapping combustor and a slagging boiler furnace of a 300 MW power generation unit by flame spontaneous emission spectroscopy (FES) for simultaneous measuring. The result shows that both ZD-FK and ZD-HSQ (Fukang coal and Hongshaquan coal, Xinjiang Zhundong high-alkali coal) combustion flame temperatures are around 1400 °C at the outlet of the cyclone burner while the latter is slightly higher. The sodium concentration in the gas phase increases with the rising of the initial combustion temperature and unit load for one kind of coal, and the level of sodium concentration has a strong correlation with the Na content for different coal. Most of the sodium in the high temperature zone of the furnace exists in the form of gas phase, and more sodium migrates to fly ash. Combined with the analysis of fly ash and liquid slag samples, a closed-loop analysis of the Na migration path could be established.

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32

Crnomarković, Nenad, Srđan Belošević, Stevan Nemoda, Ivan Tomanović, and Aleksandar Milićević. "DETERMINATION OF THE WALL VARIABLES WITHIN THE ZONAL MODEL OF RADIATION INSIDE A PULVERIZED COAL-FIRED FURNACE." Facta Universitatis, Series: Mechanical Engineering 16, no. 2 (August 1, 2018): 219. http://dx.doi.org/10.22190/fume180227021c.

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Determination of the wall variables (wall emissivities, wall temperatures, and heat fluxes) when the zonal model of radiation is used in numerical simulations of processes inside a pulverized coal-fired furnaces is described. Two methods for determination of the wall variables, i.e., a repeated run of numerical simulation (RRNS) and a temporary correction of the total exchange areas (TCTEA) are compared. Investigation was carried out for three values of the flame total extinction coefficient and four values of the initial wall emissivities. Differences of the wall variables were determined using the arithmetic means (AMs) of the relative differences. The AMs of the relative differences of the wall variables increased with an increase in the flame total extinction coefficient and changed a little with an increase in the initial values of the wall emissivities. For the selected furnace, the smallest differences of the wall variables were obtained for Kt=0.3 m-1 and ew,in=0.7. Although both methods can be used for determination of the wall variables, the RRNS method was recommended because the manipulation with files was easier for it. mmended because the manipulation with files was easier for it.

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Muthukumar, K., K. Amirtham, and A. Sundaramahalingam. "Study on spontaneous combustion and environmental pollution in a coal storage yard." IOP Conference Series: Earth and Environmental Science 1125, no. 1 (December 1, 2022): 012001. http://dx.doi.org/10.1088/1755-1315/1125/1/012001.

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Abstract In coal fired power plants, Bituminous coal grade C is received through wagons from coal mines, unloaded, and separated as sized coal and coal dust. Coal is stored in stockpiles of around 22000 square metres that have been specified for coal storage. The size of each stockpile is 15’ in length, 10’ in width, and 10’ in height and the temperature in the locality is around 38 °C, with summer temperatures reaching 42 °C. Spontaneous combustion occurred more than 90 times in a six month time. More than 75% of the area always has coal-stock since the industries are far away from the coal mines and more than 50 big furnaces use the coal gas as fuel. Raw coal and coal dust have higher sulphur content, a very low onset temperature, and the highest volatile matter content. Hence, it undergoes spontaneous combustion easily. The fixed carbon of sized coal is higher, and therefore its susceptibility to unstructured burning is lesser contrast with two new trials since it will have a higher calorific value. The quality of coal has the highest impact, while low-grade coal is most responsible for spontaneous combustion, and high-grade coal is the least susceptible to warming. The main indicators are physical symptoms such as odor, smoke, or heat sensation. The polluted environments contain CO, CO2, CH4, C2H4, and C2H6.

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Rousseau, Pieter, Ryno Laubscher, and Brad Travis Rawlins. "Heat Transfer Analysis Using Thermofluid Network Models for Industrial Biomass and Utility Scale Coal-Fired Boilers." Energies 16, no. 4 (February 9, 2023): 1741. http://dx.doi.org/10.3390/en16041741.

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Integrated whole-boiler process models are useful in the design of biomass and coal-fired boilers, and they can also be used to analyse different scenarios such as low load operation and alternate fuel firing. Whereas CFD models are typically applied to analyse the detail heat transfer phenomena in furnaces, analysis of the integrated whole-boiler performance requires one-dimensional thermofluid network models. These incorporate zero-dimensional furnace models combined with the solution of the fundamental mass, energy, and momentum balance equations for the different heat exchangers and fluid streams. This approach is not new, and there is a large amount of information available in textbooks and technical papers. However, the information is fragmented and incomplete and therefore difficult to follow and apply. The aim of this review paper is therefore to: (i) provide a review of recent literature to show how the different approaches to boiler modelling have been applied; (ii) to provide a review and clear description of the thermofluid network modelling methodology, including the simplifying assumptions and its implications; and (iii) to demonstrate the methodology by applying it to two case study boilers with different geometries, firing systems and fuels at various loads, and comparing the results to site measurements, which highlight important aspects of the methodology. The model results compare well with values obtained from site measurements and detail CFD models for full load and part load operation. The results show the importance of utilising the high particle load model for the effective emissivity and absorptivity of the flue gas and particle suspension rather than the standard model, especially in the case of a high ash fuel. It also shows that the projected method provides better results than the direct method for the furnace water wall heat transfer.

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Zhang, L., S. X. Wang, Q. R. Wu, F. Y. Wang, C. J. Lin, L. M. Zhang, M. L. Hui, and J. M. Hao. "Mercury transformation and speciation in flue gases from anthropogenic emission sources: a critical review." Atmospheric Chemistry and Physics Discussions 15, no. 22 (November 24, 2015): 32889–929. http://dx.doi.org/10.5194/acpd-15-32889-2015.

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Abstract. Mercury transformation mechanisms and speciation profiles are reviewed for mercury formed in and released from flue gases of coal-fired boilers, non-ferrous metal smelters, cement plants, iron and steel plants, municipal solid waste incinerators, and biomass burning. Mercury in coal, ores and other raw materials is released to flue gases in the form of Hg0 during combustion or smelting in boilers, kilns or furnaces. Decreasing temperature from over 800 °C to below 300 °C in flue gases leaving boilers, kilns or furnaces promotes homogeneous and heterogeneous oxidation of gaseous elemental mercury (Hg0) to gaseous divalent mercury (Hg2+), with a portion of Hg2+ adsorbed onto fly ash to form particulate-bound mercury (Hgp). Halogen is the primary oxidizer for Hg0 in flue gases, and active components (e.g.,TiO2, Fe2O3, etc.) on fly ash promote heterogeneous oxidation and adsorption processes. In addition to mercury removal, mercury transformation also occurs when passing through air pollution control devices (APCDs), affecting the mercury speciation in flue gases. In coal-fired power plants, selective catalytic reduction (SCR) system promotes mercury oxidation by 34–85 %, electrostatic precipitator (ESP) and fabric filter (FF) remove over 99 % of Hgp, and wet flue gas desulfurization system (WFGD) captures 60–95 % of Hg2+. In non-ferrous metal smelters, most Hg0 is converted to Hg2+ and removed in acid plants (APs). For cement clinker production, mercury cycling and operational conditions promote heterogeneous mercury oxidation and adsorption. The mercury speciation profiles in flue gases emitted to the atmosphere are determined by transformation mechanisms and mercury removal efficiencies by various APCDs. For all the sectors reviewed in this study, Hgp accounts for less than 5 % in flue gases. In China, mercury emission has a higher fraction (66–82 % of total mercury) in flue gases from coal combustion, in contrast to a greater Hg2+ fraction (29–90 %) from non-ferrous metal smelting, cement and iron/steel production. The higher Hg2+ fractions shown here than previous estimates may imply stronger local environmental impacts than previously thought, caused by mercury emissions in East Asia. Future research should focus on determining mercury speciation in flue gases from iron and steel plants, waste incineration and biomass burning, and on elucidating the mechanisms of mercury oxidation and adsorption in flue gases.

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36

Zhang, Lei, Shuxiao Wang, Qingru Wu, Fengyang Wang, Che-Jen Lin, Leiming Zhang, Mulin Hui, Mei Yang, Haitao Su, and Jiming Hao. "Mercury transformation and speciation in flue gases from anthropogenic emission sources: a critical review." Atmospheric Chemistry and Physics 16, no. 4 (February 29, 2016): 2417–33. http://dx.doi.org/10.5194/acp-16-2417-2016.

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Abstract. Mercury transformation mechanisms and speciation profiles are reviewed for mercury formed in and released from flue gases of coal-fired boilers, non-ferrous metal smelters, cement plants, iron and steel plants, waste incinerators, biomass burning and so on. Mercury in coal, ores, and other raw materials is released to flue gases in the form of Hg0 during combustion or smelting in boilers, kilns or furnaces. Decreasing temperature from over 800 °C to below 300 °C in flue gases leaving boilers, kilns or furnaces promotes homogeneous and heterogeneous oxidation of Hg0 to gaseous divalent mercury (Hg2+), with a portion of Hg2+ adsorbed onto fly ash to form particulate-bound mercury (Hgp). Halogen is the primary oxidizer for Hg0 in flue gases, and active components (e.g., TiO2, Fe2O3, etc.) on fly ash promote heterogeneous oxidation and adsorption processes. In addition to mercury removal, mercury transformation also occurs when passing through air pollution control devices (APCDs), affecting the mercury speciation in flue gases. In coal-fired power plants, selective catalytic reduction (SCR) system promotes mercury oxidation by 34–85 %, electrostatic precipitator (ESP) and fabric filter (FF) remove over 99 % of Hgp, and wet flue gas desulfurization system (WFGD) captures 60–95 % of Hg2+. In non-ferrous metal smelters, most Hg0 is converted to Hg2+ and removed in acid plants (APs). For cement clinker production, mercury cycling and operational conditions promote heterogeneous mercury oxidation and adsorption. The mercury speciation profiles in flue gases emitted to the atmosphere are determined by transformation mechanisms and mercury removal efficiencies by various APCDs. For all the sectors reviewed in this study, Hgp accounts for less than 5 % in flue gases. In China, mercury emission has a higher Hg0 fraction (66–82 % of total mercury) in flue gases from coal combustion, in contrast to a greater Hg2+ fraction (29–90 %) from non-ferrous metal smelting, cement and iron and/or steel production. The higher Hg2+ fractions shown here than previous estimates may imply stronger local environmental impacts than previously thought, caused by mercury emissions in East Asia. Future research should focus on determining mercury speciation in flue gases from iron and steel plants, waste incineration and biomass burning, and on elucidating the mechanisms of mercury oxidation and adsorption in flue gases.

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37

Mohammad Nurizat Rahman and Nor Fadzilah Binti Othman. "A Numerical Model for Ash Deposition Based on Actual Operating Conditions of a 700 MW Coal-Fired Power Plant: Validation Feedback Loop via Structural Similarity Indexes (SSIMs)." CFD Letters 14, no. 1 (January 11, 2022): 99–111. http://dx.doi.org/10.37934/cfdl.14.1.99111.

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The combustion of coals will result in significant ash-related issues, which will ultimately lead to the efficiency loss of coal-fired utility boilers. While there have been numerous attempts to predict ash deposition dynamics using numerical approaches, the majority of these models were constructed using experimental data from pilot-scale furnaces and without integration with combustion models. Therefore, the current study collects meaningful power plant data from ash sampling activities at one of Malaysia's 700 MW sub-critical coal-fired power plants, enabling the ash deposition behavior in a real coal-fired utility boiler to be adequately captured and converted into a reliable ash deposition numerical model. The validation feedback loop of the ash deposition model was run using in-situ measurement data (ash sampling picture) and the actual power plant operating conditions during the ash sampling activities. The image processing algorithm was used to determine the degree of similarity between the actual ash sampling image and the predicted ash deposition image from the numerical model. Prior to the validation feedback loop, the overall numerical model (solver, combustion, turbulence, radiation) was successfully validated with the FEGT from the actual power plant, revealing a difference of less than 5 %. The current study found that the baseline ash deposition model (created from experimental data) underestimates the quantity of ash deposition gathered. The validation feedback loop of the baseline ash deposition model successfully established a new set of impaction efficiency constants, which increased the similarity of the images between the actual and predicted ash depositions. The current study's drawback, however, is mostly in the validation basis, which is largely qualitative in nature. Although the Structural Similarity Index (SSIM) value is useful for comparing the similarity of images between actual and predicted ash depositions, a more quantitative measurement that can provide extra meaningful data points and higher accuracy on the deposited ash is preferable. However, based on this modified version of the ash deposition model, the agreement is found to be satisfactory in terms of gaining a rudimentary insight of the ash deposition behavior in a coal-fired boiler.

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Hanjalic´, K., and I. Smajevic´. "Detonation-Wave Technique for On-Load Deposit Removal From Surfaces Exposed to Fouling: Part I—Experimental Investigation and Development of the Method." Journal of Engineering for Gas Turbines and Power 116, no. 1 (January 1, 1994): 223–30. http://dx.doi.org/10.1115/1.2906797.

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The paper presents a description and results of the experimental research, development, and full-scale testing of a new technique for cleaning gas-swept surfaces exposed to fouling, such as found in boilers, furnaces, heat exchangers, reactors, and gas ducts, by means of detonation waves. Part I describes the principles and reports on experimental investigations and optimization of the technique. Part II reports on several years of experience in applying the technique in full-scale operation in two large coal-fired boilers. Experiments involved detailed measurements of the pressure wave characteristics at a laboratory-scale model of a boiler furnace at a range of operating conditions and produced necessary information for optimum design and operation of the detonation wave generator. The investigation enabled a close insight into the detonation and shock wave generation, their behavior during propagation through the connecting ducts, and attenuation in the inner space of the model furnace. A good indication has also been obtained of the wave impact and effects on deposit-removal from different packages of tube bundles, which were placed in the model boiler in order to mimic boiler heating surfaces.

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39

STRÖHLE, J., H. KNAUS, U. SCHNELL, and K. R. G. HEIN. "A Radiation Model for the Numerical Simulation of Coal-Fired Furnaces Using Body-Fitted Grids." Combustion Science and Technology 153, no. 1 (April 2000): 127–39. http://dx.doi.org/10.1080/00102200008947255.

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40

Guo, Jiasen, and Hongliang Ding. "Research Progress of Flexible Peak Shaving Technology for Coal-Fired Boilers." Highlights in Science, Engineering and Technology 67 (September 21, 2023): 246–61. http://dx.doi.org/10.54097/hset.v67i.11740.

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In the face of the pressing challenges of climate change and carbon emissions, China's energy and power sectors are actively working towards the strategic goal of establishing a new power system, where wind and solar energy will constitute a rapidly expanding portion of grid-connected power generation. Nevertheless, the inherent characteristics of these renewable energy sources, such as their randomness, intermittency, and volatility, pose significant challenges to ensuring the secure and stable operation of the power grid. Presently, China heavily relies on pulverized coal power plants, which lack the flexibility required to accommodate the fluctuating demands posed by renewable energy generation. Overcoming this technical obstacle and enabling efficient grid integration of renewable energy necessitates a thorough exploration of the potential of existing pulverized coal furnaces for flexible peaking operations, especially under extreme peak shaving conditions. To address this challenge, coal self-preheating combustion technology has emerged as a pioneering solution developed by the Institute of Engineering Thermophysics, Chinese Academy of Sciences. By implementing preheating modification activation, this innovative approach alters the traditional combustion reaction path of pulverized coal, significantly enhancing its reaction activity. This advancement holds immense promise for achieving efficient and stable combustion, as well as facilitating rapid load changes in pulverized coal boilers operating at low loads. This study primarily focuses on discussing prevalent means of peaking technology, including low-load stable combustion technology, rapid load regulation technology, coupled peaking technology, and the development status of peaking technology for coal power units. Through in-depth research and innovation, it is anticipated that the effectiveness and viability of peaking technology will be further enhanced, promoting the sustainable development of pulverized coal boiler generating units and optimizing the operation of energy systems. Furthermore, the self-preheating combustion technology will increasingly play a pivotal role in multiple sectors and directions, such as flexible and deep peaking of coal power, driving the advancement and adoption of clean and effective coal utilization technology.

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41

Crnomarkovic, Nenad, Srdjan Belosevic, Ivan Tomanovic, and Aleksandar Milicevic. "Weighted sum of gray gases model optimization for numerical investigations of processes inside pulverized coal-fired furnaces." Journal of Thermal Science 26, no. 6 (November 9, 2017): 552–59. http://dx.doi.org/10.1007/s11630-017-0973-0.

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42

Liu, Z. H., C. G. Zheng, and H. W. Xing. "Radiative Properties of Residual Char and Its Effects on Radiative Heat Transfer in Pulverized Coal Fired Furnaces." Developments in Chemical Engineering and Mineral Processing 8, no. 3-4 (May 15, 2008): 269–79. http://dx.doi.org/10.1002/apj.5500080307.

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43

Shabanov, Yerbol, Yerbolat Makhambetov, Zhalgas Saulebek, Ruslan Toleukadyr, Sailaubai Baisanov, Nurzhan Nurgali, Azamat Shotanov, Murat Dossekenov, and Yerlan Zhumagaliyev. "Pilot Tests of Pre-Reduction in Chromium Raw Materials from Donskoy Ore Mining and Processing Plant and Melting of High-Carbon Ferrochromium." Metals 14, no. 2 (February 6, 2024): 202. http://dx.doi.org/10.3390/met14020202.

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Experiments were conducted to pilot the initial reduction in chromium raw materials using the innovative Hoganas technology in a tunnel furnace. To simulate the process, a gas-fired bogie hearth furnace was employed. Technological containers made of silicon carbide crucibles were utilized. Sixteen different combinations of ore and coal mixtures were employed for the initial reduction process. Their total mass was more than 20 tons. Their heat treatment was performed at different temperatures and durations. During the pilot tests, the possibility of achieving chromium metallization was confirmed. Thus, it explains the application of a pre-reduction instead of the sintering or charge heating before the ferrochromium melting, i.e., the power consumption is minimized during the final remelting of the product in DC furnaces. The pilot melting of three batches of the pre-reduced chromium raw materials with various chromium metallization degrees has been tested in the ore-smelting furnace at Zh. Abishev Chemical–Metallurgical Institute (Karaganda). The capacity was 0.2 MVA. To evaluate the technical and economic efficiency of remelting pre-reduced chromium raw materials in commercial DC furnaces, a specific batch of primary ingredients for producing high-carbon ferrochromium, including chromite ore, coke, and quartz flux, was successfully melted in a segregated phase. As a result of the study, it was found that the specific energy consumption for melting high-carbon ferrochromium in the pilot furnace depends on the chromium metallization degree. The researchers tested a range of chromium metallization degrees from 0 to 65% and determined the corresponding specific energy consumption for each degree. Using the data obtained from the study, the researchers were able to assess the melting indexes of high-carbon ferrochromium in a larger 72 MW furnace. They found that by using a pre-reduced product with a chromium metallization degree of 65%, it was possible to reduce the specific energy consumption by half, to around 3.4 MW·h per ton of chromium. Overall, this study highlights the importance of considering the chromium metallization degree when determining the specific energy consumption for melting high-carbon ferrochromium. By optimizing the metallization degree, significant energy savings can be achieved, leading to more efficient and sustainable production processes.

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Bearce, Bradford C. "Coal Bottom Ash as a Component of Floriculture Root Media." HortScience 33, no. 2 (April 1998): 203b. http://dx.doi.org/10.21273/hortsci.33.2.0203b.

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Our research emphasis has been on utilization of industrial by-products as components of plant root substrates. Coal bottom ash (CBA) collects at the base of furnaces of coal-fired power plants, in contrast to fly ash, which is removed from stack fumes by electrostatic precipitators. A majority of CBA is disposed in landfills. Its low cost and availability in large quantities (in 1994, >14 million tons were produced in the United States, of which only ≈5 million tons were marketed) recommend it for trial as a component of root media, which currently contain far more expensive ingredients. CBA tends to increase pH and EC and decrease water and air capacities of root media. When used as a root medium in a closed loop nutriculture system, it caused an increase in Ca, K, and Na in the nutrient solution. Crops grown in CBA root media include pot and cut chrysanthemums, roses, rhododendrons, poinsettias, Easter lilies, peperomia, zonal and ivy geraniums, impatiens, New Guinea impatiens, and hydrangeas. In general, growth parameters such as plant dry weight and flower number tended to decline at media CBA levels of 75% or more. At CBA levels of 50% or less, these parameters tended to equal or surpass those of plants in control (0% CBA) media.

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Li, Wenhao, Chun Lou, Yipeng Sun, and Huaichun Zhou. "Estimation of radiative properties and temperature distributions in coal-fired boiler furnaces by a portable image processing system." Experimental Thermal and Fluid Science 35, no. 2 (February 2011): 416–21. http://dx.doi.org/10.1016/j.expthermflusci.2010.10.005.

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46

Stojiljkovic, Dragoslava, Vladimir Jovanovic, Milan Radovanovic, Nebojsa Manic, and Ivo Radulovic. "Investigations of combustion process in combined cooker-boiler fired on solid fuels." Thermal Science 10, no. 4 (2006): 121–30. http://dx.doi.org/10.2298/tsci0604121s.

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The aim of the investigation was to make some reconstructions on the existing stove used for cooking and baking and to obtain the combined cooker-boiler which will fulfill the demands of European standard EN 12815. Implementation of modern scientific achievements in the field of combustion on stoves and furnaces fired on solid fuels was used. During the investigations four various constructions were made with different fresh air inlet and secondary air supply with the intention to obtain more complete combustion with increased efficiency and reduced CO emission. Three different fuels were used: firewood, coal, and wood briquette. A numerous parameters were measured: fuel weight changes during the combustion process, temperature of inlet and outlet water, flue gas composition (O2, CO, SO2, CO2, NOx), flue gas temperature, ash quantity etc. The result of the investigations is the stove with the efficiency of more than 75% - boiler Class 1 (according EN 12815) and CO emission of about 1% v/v. The results obtained during the measurements were used as parameters for modeling of combustion process. .

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Smajević, Izet, and Kemal Hanjalić. "Aerovalved Pulse Combustor for Enhancing Efficiency and Sustainability of Fossil Energy Conversion." B&H Electrical Engineering 17, s1 (December 1, 2023): 53–60. http://dx.doi.org/10.2478/bhee-2023-0018.

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Abstract The paper actualizes earlier research in developing a pulse combustion technique for enhancing the efficacy of utility and industrial boilers and furnaces. Some unpublished results of the experimental investigation of self-sustained pulsating combustion of a gas fuel in an aerovalved pulse combustor (PC) are presented. Relationships have been established between all important design and operating parameters and the combustion characteristics. It was demonstrated that a well-designed pulse combustor can operate efficiently in a stable self-pumping regime in a wide range of operating conditions with the loading from 20% to 100% of the maximum power. While a PC can operate autonomously as a gas burner, the present focus is on their use for mitigating slug and ash deposits on heating surfaces of coal- or biomass fired power and industrial boilers, thus providing an alternative to the proven detonation pulse (DPC) or other techniques for on-line cleaning of heating surfaces during the operation of power and industrial boilers.

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Grimmer, G., J. Jacob, G. Dettbarn, and K. W. Naujack. "Determination of polycyclic aromatic hydrocarbons, azaarenes, and thiaarenes emitted from coal-fired residential furnaces by gas chromatography/mass spectrometry." Fresenius' Zeitschrift für analytische Chemie 322, no. 6 (November 1985): 595–602. http://dx.doi.org/10.1007/bf00464595.

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Temuujin, Jadambaa, Damdinsuren Munkhtuvshin, and Claus H. Ruescher. "The Latest Research in Mongolia on the Utilization of Coal Combustion By-Products." Solid State Phenomena 323 (August 30, 2021): 8–13. http://dx.doi.org/10.4028/www.scientific.net/ssp.323.8.

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With a geological reserve of over 170 billion tons, coal is the most abundant energy source in Mongolia with six operating thermal power stations. Moreover, in Ulaanbaatar city over 210000 families live in the Ger district and use over 800000 tons of coal as a fuel. The three thermal power plants in Ulaanbaatar burn about 5 million tons of coal, resulting in more than 500000 tons of coal combustion by-products per year. Globally, the ashes produced by thermal power plants, boilers, and single ovens pose serious environmental problems. The utilization of various types of waste is one of the factors determining the sustainability of cities. Therefore, the processing of wastes for re-use or disposal is a critical topic in waste management and materials research. According to research, the Mongolian capital city's air and soil quality has reached a disastrous level. The main reasons for air pollution in Ulaanbaatar are reported as being coal-fired stoves of the Ger residential district, thermal power stations, small and medium-sized low-pressure furnaces, and motor vehicles. Previously, coal ashes have been used to prepare advanced materials such as glass-ceramics with the hardness of 6.35 GPa, geopolymer concrete with compressive strength of over 30 MPa and zeolite A with a Cr (III) removal capacity of 35.8 mg/g. Here we discuss our latest results on the utilization of fly ash for preparation of a cement stabilized base layer for paved roads, mechanically activated fly ash for use in concrete production, and coal ash from the Ger district for preparation of an adsorbent. An addition of 20% fly ash to 5-8% cement made from a mixture of road base gave a compressive strength of ~ 4MPa, which exceeds the standard. Using coal ashes from Ger district prepared a new type of adsorbent material capable of removing various organic pollutants from tannery water was developed. This ash also showed weak leaching characteristics in water and acidic environment, which opens up an excellent opportunity to utilize.

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Friedman, J., P. Koundakjian, D. Naylor, and D. Rosero. "Heat Transfer to Small Horizontal Cylinders Immersed in a Fluidized Bed." Journal of Heat Transfer 128, no. 10 (March 22, 2006): 984–89. http://dx.doi.org/10.1115/1.2345425.

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Abstract:

Heat transfer to horizontal cylinders immersed in fluidized beds has been extensively studied, but mainly in the context of heat transfer to boiler tubes in coal-fired beds. As a result, most correlations in the literature have been derived for cylinders of 25-50mm diameter in vigorously fluidizing beds. In recent years, fluidized bed heat treating furnaces fired by natural gas have become increasingly popular, particularly in the steel wire manufacturing industry. These fluidized beds typically operate at relatively low fluidizing rates (G∕Gmf<5) and with small diameter wires (1-6mm). Nusselt number correlations developed based on boiler tube studies do not extrapolate down to these small size ranges and low fluidizing rates. In order to obtain reliable Nusselt number data for these size ranges, an experimental investigation has been undertaken using two heat treating fluidized beds; one a pilot-scale industrial unit and the other a lab-scale (300mm diameter) unit. Heat transfer measurements were obtained using resistively heated cylindrical samples ranging from 1.3 to 9.5mm in diameter at fluidizing rates ranging from approximately 0.5×Gmf (packed bed condition) to over 10×Gmf using aluminum oxide sand particles ranging from dp=145-330μm (50–90 grit). It has been found that for all cylinder sizes tested, the Nusselt number reaches a maximum near 2×Gmf, then remains relatively steady (±5-10%) to the maximum fluidizing rate tested, typically 8-12×Gmf. A correlation for maximum Nusselt number is developed.

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Journal articles on the topic 'Coal-fired furnaces'

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