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1
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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Wan, Wen Jun, Zhi Yuan Fan, Wei Jian Huang, and Shi He Chen. "Dynamic Characteristics and Mathematical Models of Filled Level for Ball Mills with Double Inlets and Outlets." Advanced Materials Research 1008-1009 (August 2014): 988–94. http://dx.doi.org/10.4028/www.scientific.net/amr.1008-1009.988.
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Ball mills with double inlets and outlets (BMDIO) are widely equipped in milling systems of thermal power plants because of BMDIOs’ vantage on being able to pulverize various raw coal. In this paper, dynamic characteristics of mill’s coal level were studied by pulverizing coal mechanism analysis. Furthermore, models for filled level of mill were obtained with mathematical Equations. The nonlinear, strong coupling and large lag features of BMDIO’s dynamic characteristics were demonstrated by the model for level of materiel constructed in this paper. And, the model would be become the available theory basis for the calculation of pulverized coal into furnace and design of combustion in fossil-fired thermal unit.
3
Crnomarkovic, Nenad, Miroslav Sijercic, Srdjan Belosevic, Dragan Tucakovic, and Titoslav Zivanovic. "Influence of application of Hottel’s zonal model and six-flux model of thermal radiation on numerical simulations results of pulverized coal fired furnace." Thermal Science 16, no. 1 (2012): 271–82. http://dx.doi.org/10.2298/tsci110627126c.
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Difference of results of numerical simulation of pulverized coal fired furnace when mathematical models contain various radiation models has been described in paper. Two sets of numerical simulations of pulverized coal fired furnace of 210 MWe power boiler have been performed. One numerical simulation has contained Hottel?s zonal model, whereas the other numerical simulation has contained six-flux model. Other details of numerical simulations have been identical. The influence of radiation models has been examined through comparison of selected variables (gas-phase temperature, oxygen concentration, and absorbed radiative heat rate of surface zones of rear and right furnace walls), selected global parameters of furnace operation (total absorbed heat rate by all furnace walls and furnace exit gas-phase temperature). Computation time has been compared as well. Spatially distributed variables have been compared through maximal local differences and mean differences. Maximal local difference of gas-phase temperature has been 8.44%. Maximal local difference of absorbed radiative heat rate of the surface zones has been almost 80.0%. Difference of global parameters of furnace operation has been expressed in percents of value obtained by mathematical model containing Hottel?s zonal model and has not been bigger than 7.0%. Computation time for calculation of 1000 iterations has been approximately the same. Comparison with other radiation models is necessary for assessment of differences.
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Wen, Xiao Qiang. "Comparison and Application of Two Mathematical Models in Predicting and Determining the State of Deposition and Slagging of Coal Burning Boiler." Advanced Materials Research 818 (September 2013): 240–45. http://dx.doi.org/10.4028/www.scientific.net/amr.818.240.
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Building a model to predict the state of slag on coal-fired boilers is a good way to optimize the coal combustion and reduce the risk of boiler slag. This paper built new models based on vague sets to predict the state of slag on coal-fired boilers, in which there were six input vectors, which were softening temperature, SiO2-Al2O3 ratio, alkali-acid ratio, percentage of silicon content, the dimensionless average temperature furnace and the dimensionless inscribed circle diameter furnace, and one output vectors, which was slagging degree. Two methods, which were based on the sense of distance and symmetric fuzzy cross entropy, were proposed to calculate the similarity between vague sets. 10 coal burning boilers were selected as known samples and the feasibility of the new methods was proved by the result of predicting the state of slag on the four coal burning boilers from Jilin heat and power plant, Xinli power plant, Jinzhou power plant and Qinhuangdao power plant. Through predicting and determining, it proves that the two pattern recognition models are high in prediction accuracy. Compared with the normal method, it is easier for operators to predict, determine the slagging state and reduce disturbance as far as possible. Besides, a prediction system has been developed by object-oriented high-level language accordingly.
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Heng, Li Jun, Kun Jie Duan, and Chang Zheng He. "Study on Mathematical Simulation of Nitrogen Oxides (NOx) Formation of Coal-Fired Boiler." Advanced Materials Research 354-355 (October 2011): 319–24. http://dx.doi.org/10.4028/www.scientific.net/amr.354-355.319.
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There exist certain limitations to research the law and influence factors of the nitrogen oxides formation only with the help of field tests, because the nitrogen oxides formation of the boiler is influenced by various factors. The flow, combustion mathematical models interrelated and so on are established taking the 410t/h boiler fired tangentially as a prototype by the use of the fluent software. All the mathematical models are verified and modified with the aid of routine field test data, and the accuracy and reliability of the mathematical models are improved. Then NOx formation performance is stimulated in allusion to the influence factors without field test conditions. The mathematical simulation results show that mathematical models can provide a sufficient theoretical basis to analyze accurately combustion and NOx formation law in furnace, and the deficiencies of field tests have been made up.
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Milicevic, Aleksandar, Srdjan Belosevic, Ivan Tomanovic, Nenad Crnomarkovic, and Dragan Tucakovic. "Development of mathematical model for co-firing pulverized coal and biomass in experimental furnace." Thermal Science 22, no. 1 Part B (2018): 709–19. http://dx.doi.org/10.2298/tsci170525206m.
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A comprehensive mathematical model for prediction of turbulent transport processes and reactions during co-combustion of pulverized fuels in furnace fired by 150 kW swirl stabilized-burner has been developed. Numerical simulations have been carried out by using an in-house developed computer code, with Euler-Lagrangian approach to the two-phase flow modelling and sub-models for individual phases during complex combustion process: evaporation, devolatilization, combustion of volatiles, and char combustion. For sub-model of coal devolatilization the approach of Merrick is adopted, while for biomass devolatilization the combination models of Merrick, and of Xu and Tomita are selected. Products of devolatilization of both the pulverized coal and biomass are considered to contain the primary gaseous volatiles and tar, which further decomposes to secondary gaseous volatiles and residual soot. The residual soot in tar and carbon in coal and biomass char are oxidized directly, with ash remaining. For volatiles combustion the finite rate/eddy break-up model is chosen, while for char oxidation the combined kinetic-diffusion model is used. The comprehensive combustion model is validated against available experimental data from the case-study cylindrical furnace. The agreement of the simulations with the data for the main species in the furnace is quite good, while some discrepancies from experimental values are found in the core zone. The presented model is a good basis for further research of co-combustion processes and is able to provide analysis of wide range of pulverized fuels, i. e. coal and biomass. At the same time, the model is relatively simple numerical tool for effective and practical use.
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Adili, Tahmineh, Zohreh Rostamnezhad, Ali Chaibakhsh, and Ali Jamali. "Flame Failures and Recovery in Industrial Furnaces: A Neural Network Steady-State Model for the Firing Rate Setpoint Rearrangement." International Journal of Chemical Engineering 2018 (June 20, 2018): 1–15. http://dx.doi.org/10.1155/2018/3790849.
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Burner failures are common abnormal conditions associated with industrial fired heaters. Preventing from economic loss and major equipment damages can be attained by compensating the lost heat due to burners’ failures, which can be possible by defining appropriate setpoints to rearrange the firing rates for healthy burners. In this study, artificial neural network models were developed for estimating the appropriate setpoints for the combustion control system to recover an industrial fired-heater furnace from abnormal conditions. For this purpose, based on an accurate high-order mathematical model, constrained nonlinear optimization problems were solved using the genetic algorithm. For different failure scenarios, the best possible excess firing rates for healthy burners to recover the furnace from abnormal conditions were obtained and data were recorded for training and testing stages. The performances of the developed neural steady-state models were evaluated through simulation experiments. The obtained results indicated the feasibility of the proposed technique to deal with the failures in the combustion system.
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Glushkov, Dmitrii, Kristina Paushkina, Ksenia Vershinina, and Olga Vysokomornaya. "Slagging Characteristics of a Steam Boiler Furnace with Flare Combustion of Solid Fuel When Switching to Composite Slurry Fuel." Applied Sciences 13, no. 1 (December 29, 2022): 434. http://dx.doi.org/10.3390/app13010434.
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Two interconnected mathematical models have been developed to describe slagging of a steam boiler furnace at the macro and micro levels. The macro-level model is implemented in Ansys Fluent. Using the fuel characteristics and temperature in the furnace, this model can predict the characteristics of ash formation on heat exchanger tubes when the melting temperature of the mineral part of solid fossil fuel is exceeded. The obtained values of slagging rates are used as initial data in the software implementation of the original Matlab microlevel model. Under conditions of dynamic change in the thickness of the slag layer, this model can evaluate the heat transfer characteristics in the hot gas/slag layer/tube wall/water coolant system. The results showed that switching a coal-fired boiler from a solid fossil fuel to a fuel slurry will improve stability and uninterrupted boiler operation due to a lower slagging rate. The combustion of coal water slurries with petrochemicals compared with coal–water fuel is characterized by higher maximum temperatures in the furnace (13–38% higher) and a lower average growth rate of slag deposits (5% lower), which reduces losses during heat transfer from flue gases to water coolant by 2%.
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Ban, Cai Ying, Xu Ao Lu, Jian Meng Yang, Xu Ran, and Feng Ying Liang. "The Partition Period of Thermodynamic Calculation and the Numerical Simulation for Lignite Blended Supercritical Boiler." Advanced Materials Research 1030-1032 (September 2014): 648–52. http://dx.doi.org/10.4028/www.scientific.net/amr.1030-1032.648.
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The purpose of this paper is to study the impact of furnace temperature and load after blending in lignite, based on CFD software FLUENT-6.3,this paper choose the appropriate geometry model and the physical and mathematical models, and numerical simulation of the different conditions 600MW supercritical once-through boiler blending lignite furnace combustion process is curried out. And through a 600MW supercritical coal-fired boiler furnace lignite blended performed sections thermodynamic calculation under different conditions, worked out the furnace flue gas temperature, CO, CO2concentration distribute trend and radiant heat each section surface heat load conditions. The specific amount were blended with 5%, 10%, 15%, 20% were not dried lignite and dried lignite 20% after five conditions. And obtained a conclusion is the temperature and radiation heating surface flue gas heat load in the overall trend under the various conditions.
10
Crnomarkovic, Nenad, Srdjan Belosevic, Ivan Tomanovic, and Aleksandar Milicevic. "Influence of the gray gases number in the weighted sum of gray gases model on the radiative heat exchange calculation inside pulverized coal-fired furnaces." Thermal Science 20, suppl. 1 (2016): 197–206. http://dx.doi.org/10.2298/tsci150603206c.
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The influence of the number of gray gases in the weighted sum in the gray gases model on the calculation of the radiative heat transfer is discussed in the paper. A computer code which solved the set of equations of the mathematical model describing the reactive two-phase turbulent flow with radiative heat exchange and with thermal equilibrium between phases inside the pulverized coal-fired furnace was used. Gas-phase radiative properties were determined by the simple gray gas model and two combinations of the weighted sum of the gray gases models: one gray gas plus a clear gas and two gray gases plus a clear gas. Investigation was carried out for two values of the total extinction coefficient of the dispersed phase, for the clean furnace walls and furnace walls covered by an ash layer deposit, and for three levels of the approximation accuracy of the weighting coefficients. The influence of the number of gray gases was analyzed through the relative differences of the wall fluxes, wall temperatures, medium temperatures, and heat transfer rate through all furnace walls. The investigation showed that there were conditions of the numerical investigations for which the relative differences of the variables describing the radiative heat exchange decrease with the increase in the number of gray gases. The results of this investigation show that if the weighted sum of the gray gases model is used, the complexity of the computer code and calculation time can be reduced by optimizing the number of gray gases.
11
Stupar, Goran, and Dragan Tucaković. "Impact of air stagging in furnace on processes in power steam boiler TPP Kostolac B." Tehnika 76, no. 1 (2021): 43–49. http://dx.doi.org/10.5937/tehnika2101043s.
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The European normatives prescribe the maximum content of 200 mg/Nm3 in dry flue gases with oxygen content of 6% for existing pulverized coal-fired power plants. In order to analyse the effects of applying some of the primary measures for NOx reduction on the overall steam boiler operation, calculational coupling of differential mathematical models has been applied. This calculation system enables reliable prediction of the performance of power steam boilers also in substoichiometric conditions, and the quality of the boiler operation can be described from the perspective of its effective, efficient, safe and ecological operation. In accorrdance to that, calculations of the steam boiler unit 1 TE Kostolac B have been carried out for the existing and the air staging combustion system. This paper presents an analysis of the influence of various parameters on the operation of the steam boiler with the application of primary measures.
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Jin, Yingai, Yanwei Sun, Yuanbo Zhang, and Zhipeng Jiang. "Research on Air Distribution Control Strategy of Supercritical Boiler." Energies 16, no. 1 (December 31, 2022): 458. http://dx.doi.org/10.3390/en16010458.
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Supercritical boilers have become a major development trend in coal-fired power plants, and the air distribution strategy is a key factor in the design and operation of making it fully combustible. In this paper, the mathematical and physical models of a 350 MW supercritical boiler is established, and the optimal air distribution mode of the boiler at different load is determined based on the furnace outlet temperature, NOx concentration, and O2 content. The air distribution control strategies were derived and the corresponding procedures were established. 160 MW and 280 MW were selected for positive pagoda and 180 MW and 230 MW for waist reduced. At 290–350 MW load, the effect of adjusting the combustion damper opening on the outlet oxygen is weak, so preferentially adjusting the SOFA damper opening can achieve better results. The results show good thermal efficiency and emission performance and are applicable to adjust the air distribution mode to achieve fuller combustion of supercritical boilers.
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Chaika, A. L., B. V. Kornilov, A. A. Moskalina, V. V. Lebed, M. G. Dzhigota, and S. A. Karikov. "Heat power analysis of performance indicators blast furnace No. 3 PJSC «AZOVSTAL IRON & STEEL WORKS» with natural gas and pulverized coal after oven overhaul of blast furnace." Fundamental and applied problems of ferrous metallurgy, no. 34 (2020): 47–61. http://dx.doi.org/10.52150/2522-9117-2020-34-47-61.
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In 2019, according to the technological assignment of the Iron and Steel Institute (ISI), the reconstruction of the blast furnace (BF) No. 3 of PJSC «AZOVSTAL IRON & STEEL WORKS» was carried out for the long-term energy-efficient production of pig iron with using pulverized coal (PCI) up to 180 kg/t with a change in the profile according to the technological task of ISI. The design of the BF No. 3 profile corresponds to the best world solutions for furnaces efficiently working with pulverized coal, and the furnace was equipped with five mathematical models of ISI («Horn», «Mine», «Heat losses», «Loading», «Slag»). Specialists of ISI developed recommendations and carried out technological support for the operation of BF No.3, which made it possible to increase the removal of pig iron from the design 2.1 t/m3 to 2.27 t/m3 and achieved the best indicators in the blast furnace workshop in terms of coke and equivalent fuel consumption by increasing the productivity of the burden system, using a rational burden loading matrix, using a rational pressure drop in the furnace, which allows the maximum use of the power of the blower machine, forcing the furnace with technical oxygen and other measures. Using the heat power model of I.D. Semikin was made a comparative analysis of the best for six months indicators of thermal performance and technical and economic indicators of BF №3 of PJSC «AZOVSTAL IRON & STEEL WORKS», with a volume of 1800 m3 before (work with natural gas) and after major repairs (work with pulverized coal and with natural gas). Using the exergy method of analysis based on the results of calculating heat and power balances, a comparative analysis of changes in the energy efficiency and environmental indicators of BF No. 3 before and after its major repairs was carried out. It shown the expediency of integrated mastering of operating modes and modernization of the blast furnace for long-term and energy-efficient operation with pulverized coal. It disclosed the mechanism for improving the technical and economic indicators of work after major repairs by changing the heat and power conditions of the blast furnace. Its shown Improvement of exergy efficiency factor and environmental performance of BF No. 3 after major repairs.
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Flek, E. S. "Development and analysis of physical and mathematical models of combustion of single drops of coal-water fuel in furnaces of boiler plants." Omsk Scientific Bulletin, no. 160 (2018): 99–102. http://dx.doi.org/10.25206/1813-8225-2018-160-99-102.
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Vedernikova, Tatyana, and Artur Vronskiy. "Comparative Analysis of Models of the Combustion Process of Coal Dust in a Turbulent Flow of a Torch of a Charcoal Boiler." System Analysis & Mathematical Modeling 3, no. 3 (December 16, 2021): 213–26. http://dx.doi.org/10.17150/2713-1734.2021.8(3).213-226.
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This article provides an overview of existing turbulence models. The scheme of combustion of pulverized coal fuel, the construction of a pulverized coal boiler unit and the process of burning coal in the furnace of a boiler unit BKZ-420-140 are considered. We analyzed the existing turbulence models and selected the most optimal mathematical model to study the combustion process of pulverized coal fuel in order to increase the efficiency of the CHPP.
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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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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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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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Dekterev, A. A., V. A. Kuznetsov, and E. S. Tepfer. "Calculation analysis of heat transfer in a four-vortex furnace of a pulverized coal boiler when operating at various loads." Journal of Physics: Conference Series 2119, no. 1 (December 1, 2021): 012149. http://dx.doi.org/10.1088/1742-6596/2119/1/012149.
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Abstract The work is devoted to the mathematical modeling of heat and mass transfer processes during flare combustion of coal dust in a four-vortex combustion chamber. For modeling, a set of interrelated models is used that describes the gas movement, thermal and radiant energy transfer, the processes of destruction and burnout of coal particles, and the formation of NOx. The simulation results showed that in a wide range of changes in the boiler load in the furnace, a stable four-vortex flow structure is formed with a fairly uniform temperature distribution in the furnace volume and a low level of NOx formation.
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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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Yuan, J. Y., P. P. Wang, C. J. Ruan, and X. Y. Huang. "Study on Co-firing characteristics of NH3 and coal in the main burning zone of the coal staged combustion." Journal of Physics: Conference Series 2208, no. 1 (March 1, 2022): 012016. http://dx.doi.org/10.1088/1742-6596/2208/1/012016.
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Abstract The mathematical models including NH3 and pulverized coal were established, and the co-combustion characteristics of NH3/pulverized coal and NOx formation process in the main combustion zone (air consumption coefficient 0.9) of coal staged combustion are studied. The gas temperature distributions and NOx generation characteristics under different ammonia/pulverized coal ratios are investigated. The results show that the ammonia combustion and the NOx production is greatly enhanced by coal combustion when the ammonia and pulverized coal are mixed. For pure ammonia combustion, due to difficult ignition and lower burning rate in the lower gas temperature environment, the NO concentration formed in the furnace and at the outlet are very low; When the proportion of NH3 is 20%, the NOx concentration at the furnace outlet is the highest; when the ammonia gas ratio is 40%, NO at the outlet is lower than that of pure pulverized coal. In addition to a large amount of NO, there are also a large amount of NO2 and N2O in the high temperature region when ammonia and pulverized coal are mixed.
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Musa, Amir A. B., Xiong Wei Zeng, Qing Yan Fang, and Huai Chun Zhou. "Numerical Simulation on Improving NOx 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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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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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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Askarova, Aliya, Saltanat Bolegenova, Symbat Bolegenova, Meruyert Beketayeva, Valeriy Maximov, Aizhan Nugymanova, and Pavel Šafařík. "SIMULATION OF LOW-GRADE COAL COMBUSTION IN REAL CHAMBERS OF ENERGY OBJECTS." Acta Polytechnica 59, no. 2 (April 30, 2019): 98–108. http://dx.doi.org/10.14311/ap.2019.59.0098.
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The aim of the work is to create new computer technologies for 3D modelling of heat and mass transfer processes in high-temperature physicochemically reacting environments that will allow to determine the aerodynamics of the flow and heat and mass transfer characteristics of technological processes occurring in the combustion chambers in existing coal-fired thermal power plants of the Republic of Kazakhstan. The novelty of the research lies in the use of the latest information technologies of 3D modelling, which will enable project participants to obtain new data on complex heat and mass transfer processes when burning pulverized coal in real combustion chambers operating in Kazakhstan’s Thermal Power Plants (TPP). A numerical simulation, including thermodynamic, kinetic and threedimensional 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 of burning high ash coals. The computer modelling methods proposed for the development are new and technically feasible, since coal-fired power plants all over the world use all types of coal. The developed technologies will allow replacing or eliminating the conduct of expensive and labour-consuming natural experiments on coal-fired power plants.
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Stanek, Wojciech, and Michał Budnik. "Exergy diagnosis of coal fired CHP plant with application of neural and regression modelling." Thermal Science 16, no. 3 (2012): 773–87. http://dx.doi.org/10.2298/tsci120509133s.
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Mathematical models of the processes, that proceed in energetic machines and devices, in many cases are very complicated. In such cases, the exact analytical models should be equipped with the auxiliary empirical models that describe those parameters which are difficult to model in a theoretical way. Regression or neural models identified basing on measurements are rather simple and are characterized by relatively short computation time. For this reason they can be effectively applied for simulation and optimization of steering and regulation processes, as well as, for control and thermal diagnosis of operation (eq. power plants or CHP plants). In the paper regression and neural models of thermal processes developed for systems of operation control of thermal plants are presented. Theoretical-empirical model of processes proceeding in coal fired CHP plant have been applied. Simulative calculations basing on these models have been carried out. Results of simulative calculations have been used for the exergetic evaluation of considered power plant. The diagnosis procedure let to investigate the formation of exergy costs in interconnected components of the system of CHP, as well as, investigate the influence of defects in operation of components on exergy losses and on the exergetic cost in other components.
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Duan, Jon, G. Cornelis van van Kooten, and A. T. M. Hasibul Islam. "Calibration of Grid Models for Analyzing Energy Policies." Energies 16, no. 3 (January 23, 2023): 1234. http://dx.doi.org/10.3390/en16031234.
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Intermittent forms of renewable energy destabilize electricity grids unless adequate reliable generating capacity and storage are available, while instability of hybrid electricity grids and cost fluctuations in fossil fuel prices pose further challenges for policymakers. We examine the interaction between renewable and traditional fossil-fuel energy sources in the context of the Alberta electricity grid, where policymakers seek to eliminate coal and reduce reliance on natural gas. We develop a policy model of the Alberta grid and, unlike earlier models, calibrate the cost functions of thermal generation using positive mathematical programming. Rather than employing constant average and marginal costs, calibration determines upward sloping supply (marginal cost) functions. The calibrated model is then used to determine an optimal generation mix under different assumptions regarding carbon prices and policies to eliminate coal-fired capacity. Results indicate that significant wind capacity can enter the Alberta grid if carbon prices are high, but that it remains difficult to eliminate reliable baseload capacity. Adequate baseload coal and/or natural gas capacity is required, which is the case even if battery storage is allowed into the system. Further, significant peak-load gas capacity will also be required to backstop intermittent renewables.
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Chandrasekharan, Sreepradha, Rames C. Panda, Bhuvaneswari Natrajan Swaminathan, Atanu Panda, and T. Thyagarajan. "Parametric identification of integrated model of a coal-fired boiler in a thermal power plant." Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 234, no. 4 (August 20, 2019): 520–33. http://dx.doi.org/10.1177/0957650919870383.
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Retrofit or replacement of few units in a subcritical facility may not only improve overall efficiency of conversion of energy in a power plant but also support sustainability issues. The primary objective of this article is to identify model parameters of a coal-fired integrated boiler and to present a comparative study on three different identification methods. This leads to select most suitable models that are applied for the developed model of the boiler of 210 MW coal-fired thermal power plants. The mathematical models of economizer, drum, and super-heater assembly are derived using mass balance and energy balance equations. The derived multi input–multi output model is then validated, and the model parameters are identified using three different identification methods namely nonlinear least square technique, maximum likelihood estimation, and expectation maximization algorithms. Identification of the plant model will essentially help to frame a good controller. In this article, parameter estimation has been carried out from real-time plant as it provides selective tool through quantitative comparative study of the three methods. The expectation maximization method has been found to provide suitable results compared to the other two methods. Model parameters of integrated boiler of a comprehensive structure have been obtained for the first time using expectation maximization method.
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Cholewiński, Maciej, and Wiesław Rybak. "Lab-scale evaluation of possible mercury speciation in flue gas and mercury emission from combustion of pulverised solid fuels." EPJ Web of Conferences 201 (2019): 06001. http://dx.doi.org/10.1051/epjconf/201920106001.
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In this work a new lab-scale method dedicated to the evaluation of both concentration and oxidation level of mercury in flue gases from pulverised fuel fired boiler was proposed. To detect the abovementioned parameters, 2 main steps need to be evaluated. Firstly, a calorimeter bomb is utilised - by a proper implementation of mass balance of mercury within substrates and products, the quantity of oxidised mercury in gaseous products can be evaluated. Then, to simulate solid fuel fired power unit and to calculate mercury concentrations in flue gases, one of the stoichiometric mathematical models of combustion process must be applied. Early validation of the method showed considerable differences between solid fuels in mercury oxidation efficiencies and concentrations in flue gasses. Four examined fuels (lignite, hard coal and 2 types of solid biomass) was investigated. Calculated mercury concentrations in raw flue gas (>700°C) varied between 4 and 75 µg/m3ref. The lowest quantity of oxidised forms ofHg in flue gases were identified in the case of investigated lignite (27% of total Hg), while significantly higher – for selected hard coal (72%) and one type of biomass (with high chlorine concentration; up to 98%).
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Cvetinovic, Dejan, Predrag Stefanovic, Vukman Bakic, and Simeon Oka. "Review of the research on the turbulence in the laboratory for thermal engineering and energy." Thermal Science 21, suppl. 3 (2017): 875–98. http://dx.doi.org/10.2298/tsci160221330c.
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Paper gives a review of the most important results of turbulence research achieved by the Laboratory for Thermal Engineering and Energy. Paper presents detailed overview of the history of the scientific research provided in the laboratory, from the beginning in the mid-60s to today, pointing out the main reasons initiating the investigations in this field. After the first period, which was mainly devoted to the research of the structure of the turbulence, since the beginning of the 80s, research is mainly oriented to the flows at high temperatures including chemical reactions and to the development and improvement of differential mathematical models as a modern and very efficient tool in the technological development. This research significantly contributed to the development of pulverized coal burners, plasma-chemical reactors, and optimization of pulverized coal fired boilers operating parameters and prediction of the greenhouse gases emissions. Most recent period includes experimental and numerical studies of the coherent structures in turbulent fluid jets, mathematical modeling of various turbulent thermal flow processes including two-phase turbulent flow in the multiphase heat exchangers and mathematical modeling of the atmospheric boundary layer.
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Novkovic, Djordje, Jela Burazer, and Aleksandar Cocic. "Comparison of different CFD software performances in the case of an incompressible air flow through a straight conical diffuser." Thermal Science 21, suppl. 3 (2017): 863–74. http://dx.doi.org/10.2298/tsci161020329n.
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Paper gives a review of the most important results of turbulence research achieved by the Laboratory for Thermal Engineering and Energy at the Vinca Insitute of Nuclear Sciences. Paper presents detailed overview of the history of the scientific research provided in the laboratory, from the beginning in the mid-60s to today, pointing out the main reasons initiating the investigations in this field. After the first period, which was mainly devoted to the research of the structure of the turbulence, since the beginning of the 80s, research is mainly oriented to the flows at high temperatures including chemical reactions and to the development and improvement of differential mathematical models as a modern and very efficient tool in the technological development. This research significantly contributed to the development of pulverized coal burners, plasma-chemical reactors, and optimization of pulverized coal fired boilers operating parameters and prediction of the greenhouse gases emissions. Most recent period includes experimental and numerical studies of the coherent structures in turbulent fluid jets, mathematical modeling of various turbulent thermal flow processes including two-phase turbulent flow in the multiphase heat exchangers and mathematical modeling of the atmospheric boundary layer.
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Żymełka, Piotr, Daniel Nabagło, Tomasz Janda, and Paweł Madejski. "Online Monitoring System of Air Distribution in Pulverized Coal-Fired Boiler Based on Numerical Modeling." Archives of Thermodynamics 38, no. 4 (December 20, 2017): 109–25. http://dx.doi.org/10.1515/aoter-2017-0027.
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Abstract Balanced distribution of air in coal-fired boiler is one of the most important factors in the combustion process and is strongly connected to the overall system efficiency. Reliable and continuous information about combustion airflow and fuel rate is essential for achieving optimal stoichiometric ratio as well as efficient and safe operation of a boiler. Imbalances in air distribution result in reduced boiler efficiency, increased gas pollutant emission and operating problems, such as corrosion, slagging or fouling. Monitoring of air flow trends in boiler is an effective method for further analysis and can help to appoint important dependences and start optimization actions. Accurate real-time monitoring of the air distribution in boiler can bring economical, environmental and operational benefits. The paper presents a novel concept for online monitoring system of air distribution in coal-fired boiler based on real-time numerical calculations. The proposed mathematical model allows for identification of mass flow rates of secondary air to individual burners and to overfire air (OFA) nozzles. Numerical models of air and flue gas system were developed using software for power plant simulation. The correctness of the developed model was verified and validated with the reference measurement values. The presented numerical model for real-time monitoring of air distribution is capable of giving continuous determination of the complete air flows based on available digital communication system (DCS) data.
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Asgaryan, Mohammad, Nigel Simms, and Shao Min Wu. "Prediction of the Remaining Service Life of Superheater and Reheater Tubes in Coal-Biomass Fired Power Plants." Advanced Materials Research 856 (December 2013): 343–48. http://dx.doi.org/10.4028/www.scientific.net/amr.856.343.
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Burning biomass in power plants is believed to result in severe fireside corrosion of superheater/reheater tubing and cause unexpected early failures of tubes. Morover, higher operating temeprtures and pressures (to increase the boiler efficiency) will also increase the risk of fireside and steamside oxidation damage to the boiler tubing and lead to shorter component lives. Predicting the remaining service life of superheater/reheater tubes in coal-biomass fired power plants is therefore an important aspect of managing such power plants. The path to this type of failure of tubes involves five processes: combustion, deposition, fireside corrosion, steam-side oxidation, and creep. To fully understand the impact of new fuel mixes and changing operating conditions on such failures, an integrated model of all of these processes is required. This work has produced an integrated set of models and so predicted the remaining life of tubes based on the conceptual and mathematical frameworks developed.
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Gorshenin, S. D., S. I. Shuvalov, E. V. Zinovieva, and l. A. Kokulin. "Improving the efficiency of fly ash reinjection in grate stoker of boiler." Vestnik IGEU, no. 5 (October 31, 2022): 18–23. http://dx.doi.org/10.17588/2072-2672.2022.5.018-023.
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A significant disadvantage of grate stokers is great carbon loss. To reduce these losses, the ash caught in the flue is returned to the furnace for afterburning. The effectiveness of this measure depends on the thermal characteristics of coal, the size of the pieces of coal and ash, the degree of carbon elimination, and the design features of the combustion chamber. Normative techniques to calculate and design grate stokers do not consider the features of coal combustion with ash return. Thus, it is relevant to develop the models that describe the creation of ash flows in the boiler path depending on its design, properties and dispersed composition of the burned coal and the aerodynamics of the combustion chamber. Mathematic simulation of the processes of particle size classification has been carried out to describe the creation of ash mass flows on the grate and in the convection chamber. To evaluate the parameters of mathematical models, simulation modeling of gas dynamics of flue gases in the combustion chamber has been carried out with SolidWorks software. The authors have developed a mathematical model and the method to identify its parameters. It allows us to obtain quantitative estimates of the economic efficiency of boilers with grate firing of coal. Thus, a computer program has been developed. The authors have used the program and the Neryungri brown coal to burn in the KV-TS-30-150 boiler. The results have shown that carbon loss without fly ash reinjection is 11,27 %. Introduction of fly-coke return unit reduces the loss up to 10,45 %. It is established that elimination of slit windows in the rotary baffle will lead to a change of the trajectories of ash particles and carbon losses reduction up to 10,17 %. Limiting the maximum size of coal pieces to 50 mm will lead to a more noticeable increase of boiler efficiency. The calculations have showed that in case the value of the carbon burn out factor equals 0,935, the carbon loss when the system of fly ash reinjection is turned off, its commissioning and, in addition, an increase of the gas density of the rotary screen will be 4 ,88%, 4,44% and 4,3% respectively. In case of a more careful assessment of the burnout factor at the level of 0,9, the carbon loss will be 7,51%, 6,87% and 6,65% respectively. The developed mathematical model makes it possible to evaluate the effect of the operation of the fly ash reinjection unit on the efficiency of the operation of a boiler with a grate stoker. Validation of a model for adequacy and for accuracy increase can be carried out after field testing of the boiler equipment.
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Vergun, О. S., L. S. Molchanov, V. G. Kislyakov, D. N. Togobitskaia, Yu S. Semenov, and О. S. Nesterov. "SCHEMATIC DIAGRAM OF THE MODEL OF END-TO-END TECHNOLOGY FOR THE PRODUCTION OF COMPETITIVE METAL PRODUCTS BY UKRAINIAN ENTERPRISES OPERATING IN UNSTABLE RAW MATERIALS AND ENERGY CONDITIONS." Fundamental and applied problems of ferrous metallurgy, no. 35 (2021): 95–107. http://dx.doi.org/10.52150/2522-9117-2021-35-95-107.
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Detailed calculation-analytical, laboratory and industrial researches of influence of sinter composition on features of technology of production of an agglomerate, and also use of such agglomerate in a complex with application of pulverized coal on results of technology and parameters of the made pig-iron are executed. The influence of the introduction of secondary materials into the sintering charge on the indicators of experimental sintering of the sinter on the example of the introduction of the use of sludge and fine dust was studied. It is established that the use of sludge blast furnace production has a greater impact on the productivity of sintering machines, to a lesser extent on the yield and cold strength. The use in the charge of fine dust electrostatic precipitators in the amount of ~ 20.5 kg/t leads to a significant reduction in productivity and strength characteristics of the sinter. Based on the results of experimental studies, the influence of the introduction of different amounts of secondary resources into the sinter charge on some characteristics of the sinter some indicators of the blast furnace operation. The balance calculations showed that with the partial replacement of pulverized coal with natural gas in the amount of 35 m3/t of cast iron, coke consumption decreased by 35 kg/t of cast iron, which led to a decrease in the cost of cast iron by 2.1%. Mathematical models created using the results of experimental data, as well as graphical dependences of reagent consumption (Mg and Mg + CaO mixture) allowed to determine the required values of specific mass consumption of reagents and on this basis to determine the cost of production of low-sulfur iron. Mathematical modeling of oxygen-converter smelting on the basis of calculation of material and heat balances and taking into account thermodynamic and physicochemical features of chemical transformations is performed. Using mathematical modeling, a comprehensive comparative analysis of the impact of the design of blast devices and the type of liquid cast iron on the technical and economic performance of steel production OS in the oxygen-converter shop of PJSC "DMK".
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Xu, Zheng, and Qi Zhu. "Analysis on Risk Factors and Spatial Variation of Pollution Sources in Urban Areas." Learning & Education 10, no. 3 (November 7, 2021): 106. http://dx.doi.org/10.18282/l-e.v10i3.2406.
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In this paper, two mathematical models are used to discuss the impact of urban pollutants on human living environment, and it is concluded that pollutants are the main cause of environmental pollution and have no direct relationship with pollution sources. Through the data of human health indicators and fitting the data sets of the two models, we want to investigate whether there are any variables related to the increase of skin cancer risk and whether the increase of cancer risk is related to the distance from coal-fired power stations in the Slovakian town of Novaky. In this work, we comparing two models, it indicates that environmental and urinary arsenic have significant impact on the cancer risk, but the spatial location cannot be consider as a direct factor on nonmelanoma skin cancer.. By comparing both models, it indicates that environmental and urinary arsenic have significant impact on the cancer risk, but the spatial location can not be consider as a direct factor on non-melanoma skin cancer. The project case, the specific planning and engineering design, should focus on strengthening the control of the pollution source, rather than merely considering spatial layout of pollutants.
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Lepikhova, V. A., N. V. Lyashenko, N. N. Chibinev, and A. V. Vyaltsev. "Monitoring System of Combustion Product of the Coal Boilers by Acoustic Emission Signals for Hazardous Emergencies Prevention." Occupational Safety in Industry, no. 4 (April 2022): 18–23. http://dx.doi.org/10.24000/0409-2961-2022-4-18-23.
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The system for monitoring combustion products in the coal-fired boilers is considered to prevent accidents during their operation. The method is based on the processing of the acoustic signal coming from the sensor, followed by the analysis of the obtained data. Acoustic signal from the moving dust cloud contains excess information about the flow dustiness. It can be used for determining the sources of an audio signal, the ways for emitting it, and the physical mechanisms of generation. Using the discrete fast Fourier transformation, two mathematical models for the analysis of dispersed dust were compiled — energy and amplitude-phase. The proposed spectral-timbre mathematical model for the time-series decomposition into a Fourier spectrum allows to obtain spectra consisting of the main and multiple timbre harmonics. Block diagram of the adaptive system for determining the concentration and disperse composition of the coal dust flow is presented (in the form of an algorithm). Concentration of the coal dust corresponding to one or another class of maximum permissible concentrations is determined by the pattern recognition method. Coefficients of the separating functions are calculated in accordance with the developed program of differential diagnostics. This problem is solved by the method of potential functions from the theory of pattern recognition. Training experiment was conducted on a closed circulation stand using the developed measuring complex. Obtained graphic map (acoustic diagram) visualizes the dust concentration zones depending on the frequencies and amplitudes of the Fourier spectral harmonics. This allows to clearly interpret the roles of the main and timbre harmonics of the spectrum. It also provides the possibility of a simple comparison of the concentrations of complex dust mixtures for the additive components of the spectrum of the analyzed acoustic signal.
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Zaidan, Martha A., Darren Wraith, Brandon E. Boor, and Tareq Hussein. "Bayesian Proxy Modelling for Estimating Black Carbon Concentrations using White-Box and Black-Box Models." Applied Sciences 9, no. 22 (November 19, 2019): 4976. http://dx.doi.org/10.3390/app9224976.
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Black carbon (BC) is an important component of particulate matter (PM) in urban environments. BC is typically emitted from gas and diesel engines, coal-fired power plants, and other sources that burn fossil fuel. In contrast to PM, BC measurements are not always available on a large scale due to the operational cost and complexity of the instrumentation. Therefore, it is advantageous to develop a mathematical model for estimating the quantity of BC in the air, termed a BC proxy, to enable widening of spatial air pollution mapping. This article presents the development of BC proxies based on a Bayesian framework using measurements of PM concentrations and size distributions from 10 to 10,000 nm from a recent mobile air pollution study across several areas of Jordan. Bayesian methods using informative priors can naturally prevent over-fitting in the modelling process and the methods generate a confidence interval around the prediction, thus the estimated BC concentration can be directly quantified and assessed. In particular, two types of models are developed based on their transparency and interpretability, referred to as white-box and black-box models. The proposed methods are tested on extensive data sets obtained from the measurement campaign in Jordan. In this study, black-box models perform slightly better due to their model complexity. Nevertheless, the results demonstrate that the performance of both models does not differ significantly. In practice, white-box models are relatively more convenient to be deployed, the methods are well understood by scientists, and the models can be used to better understand key relationships.
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Dong, Yunshan, Zongliang Qiao, Fengqi Si, Bo Zhang, Cong Yu, and Xiaoming Jiang. "A Novel Method for the Prediction of Erosion Evolution Process Based on Dynamic Mesh and Its Applications." Catalysts 8, no. 10 (September 30, 2018): 432. http://dx.doi.org/10.3390/catal8100432.
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Particle erosion is a commonly occurring phenomenon, and it plays a significantly important role in service life. However, few simulations have replicated erosion, especially the detailed evolution process. To address this complex issue, a new method for establishing the solution of the erosion evolution process was developed. The approach is introduced with the erosion model and the dynamic mesh. The erosion model was applied to estimate the material removal of erosion, and the dynamic mesh technology was used to demonstrate the surface profile of erosion. Then, this method was applied to solve a typical case—the erosion surface deformation and the expiry period of an economizer bank in coal-fired power plants. The mathematical models were set up, including gas motion, particle motion, particle-wall collision, and erosion. Such models were solved by computational fluid dynamics (CFD) software (ANSYS FLUENT), which describes the evolution process of erosion based on the dynamic mesh. The results indicate that: (1) the prediction of the erosion profile calculated by the dynamic mesh is in good agreement with that on-site; (2) the global/local erosion loss and the maximum erosion depth is linearly related to the working time at the earlier stage, but the growth of the maximum erosion depth slows down gradually in the later stage; (3) the reason for slowing down is that the collision point trajectory moves along the increasing direction of the absolute value of θ as time increases; and (4) the expiry period is shortened as the ash diameter increases.
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"Fired Heater Simulation,Modelling and Optimization." Journal of Mathematical Techniques and Computational Mathematics 1, no. 1 (September 12, 2022). http://dx.doi.org/10.33140/jmtcm.01.01.03.
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In this study a dynamic model Simulation was carried out using ASPEN HYSY for industrial refinery fired heater, it was found that Increasing the number of the tube rows in convection bank from 2 to 3 allows us to recover approximately 5% of the overall efficiency, the duty furnace has increased from 65.9MW to 68.1MW and the fuel flow has increased from 5597kg/h to 5807kg/h moreover Adding more rows has a reverse return as we start to notice increase on the flue gas temperature. Furthermore, sensitivity analysis was conducted with HYSYS to determine one of the most important parameters that affect the performance of the heater based on the data generated from the simulation. MATLAB code was generated for efficiency calculation and for parameter manipulation. well-stirred model was used for mathematical model calculations and for optimization of furnace operation, the models were validated with ASPEN Exchanger Design and Rating