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Numerical Simulation on pulverized Coal Combustion and NO_x Emissions in High Temperature Air from Circulating Fluidized Bed

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Journal of Thermal Science 2013年第3期22卷 261-268页

作者： Jianguo Zhu Ziqu Ouyang Qinggang Lu Institute of Engineering Thermophysics Chinese Academy of Sciences

High temperature air combustion is a prospecting technology in energy saving and pollutants reduction. Numerical simulation on pulverized coal combustion and NOx emissions in high temperature air from circulating fluidized bed was presented. The down-fired combustor, taken as the calculation domain, has the diameter of 220 mm and the height of 3000 mm. 2 cases with air staging combustion are simulated. Compared the simulation results with experimental data, there is a good agreement. It is found that the combustion model and NOx formation model are applicable to simulate the pulverized coal combustion and NOx emissions in high temperature air from circulating fluidized bed. The results show that there is a uniform temperature profile along the axis of the down-fired combustor. The NOx emissions are lower than those of ordinary pulverized coal combustion, and the NOx emissions are 390 mg/m3 and 352 mg/m3 in Case 1 and Case 2, respectively. At the range of 300-600 mm below the nozzle, the NO concentration decreases, mainly resulting from some homogeneous reactions and heterogeneous reaction. NO concentration has a little increase at the position of 800 mm below the nozzle as the tertiary air supplied to the combustor at the position of 600 mm below the nozzle.

关键词： pulverized coal combustion Numerical simulation High temperature air NOx

Effects of the Imbibition Ability of Extinguishant in pulverized Coals

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Transactions of Tianjin University 2019年第1期25卷 45-51页

作者： Liyan Liu Haoshuang Gong Xin Shi Dong Lv Wei Tan Guorui Zhu School of Chemical Engineering and Technology Tianjin University Key Laboratory of Building Fire Protection Engineering and Technology of MPS

The imbibition ability of extinguishant is an important factor influencing the extinguishing effect for smoldering fire in pulverized coals. The coal particle size, bulk compactness, and aqueous solution properties significantly affect the imbibition ability of extinguishment. This work aims to reveal the influence of the properties of pulverized coals and aqueous solution on the imbibition ability of extinguishant for smoldering fire through experiments and capillary theories. The imbibition height and rate were adopted to evaluate the imbibition ability of extinguishment. The results showed that a relatively small bulk compactness and a fine coal particle size negatively influenced the extinguishing process dominantly because of its high surface energy and low wettability. An additive was used to adjust the properties of aqueous solution. The liquid with a larger surface tension, a smaller contact angle, and a lower viscosity induced a better imbibition ability of extinguishment.

关键词： pulverized coal Smoldering fire Imbibition ability Capillary theories

Computational Study on Furnace Process in a Multi-burner Boiler of pulverized Coal Fired Tangentially at Four Corners

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Journal of Central South University 2000年第3期12卷 152-155页

作者： Zhou, P Mei, C Cong, GC Cent S Univ Technol Dept Appl Phys & Heat Engn Changsha 410083 Peoples R China

Aiming at the optimization of the operation condition, a general numerical method for calculating pulverized coal combustion in a full scale furnace fired tangentially at four corners is adopted. “ k ε ” turbulence model is used for the gas phases and a stochastic approach based on the Lagrangian technique is used for particle phases. Two competing reactions model for the coal devolatilization and PDF (the probability density function) method for the combustion of the gas phases are employed. In the numerical simulations, assuming the air distribution of second port level is of pagoda, waist drum and uniform type. The results show that pagoda type air distribution is advantageous to ignition and smooth combustion of pulverized coal, and suitable to inferior coal combustion in practice. In the present furnace, the igniting distance at 1st and 3rd corner is longer than that at 2nd and 4th corner. The results from numerical calculations are in good agreement with those of observed in practice.

关键词： power station boiler combustion of pulverized coal numerical simulation

Complex Processing of pulverized Fly Ash by Dry Separation Methods

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Journal of Environmental Protection 2010年第3期1卷 293-301页

作者： Vladimir Vasilievich Zyryanov Dmitry Vladimirovich Zyryanov 不详

pulverized fly ash (PFA) is produced about 500 billions tons every year in the world in a result of coals combustion. Most of the fly ash collected in power plants is disposed by deposition in landfills, situated as a rule near big cities with well developed infrastructure and high cost of land. Moreover, the pollution of environmental by fine solid wastes is inevitable and takes place in area of residing of a basic part of the population. The only solution is a complex processing of fine wastes with a production of value added materials. New conception of complex processing of PFA is proposed on the base of facilities of Electro-mass-classifier (EMC) and other techniques. The characterization of separated fractions was carried out by SEM and optic microscopy, XRD, laser diffraction, M?ssbauer spectroscopy and other methods. A fine fraction of glass microspheres presents the main interest as filler in various materials.

关键词： pulverized Fly Ash (PFA) Processing Solid Wastes Utilization Dry Separation Fly Ash Components Glass Microspheres Magnetospheres Fillers Electro-Mass-Classifier

Equation of Radiation Heat Transfer in Multiple Combustion Boiler Furnace of Fluidized Bed and pulverized Coal Firing

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Journal of Harbin Institute of Technology(New Series) 1998年第2期5卷 23-25页

作者：赵广播朱群益高志宏秦裕琨

The equation for radiation heat transfer in a multiple combustion boiler furnace with nuidized bed and pulverized coal firing is derived from direct calculation of radiation heat transfer.

关键词： pulverized coal boiler fluidized bed boiler radiation heat transfer

A　Study　on　Final　Volatile　Yield　of　pulverized　Coal　Pyrolysis　with　Thermobalance

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Journal of Harbin Institute of Technology(New Series) 1995年第3期2卷 19-22页

作者：朱群益赵广播阮根健秦裕琨

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关键词： ss: pulverized coal pyrolysis final volatile yield

Non-isothermal thermogravimetric investigation on mutual effect between bituminite and anthracite in blends for blast furnace injection

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Journal of Iron and Steel Research(International) 2019年第8期26卷 818-828页

作者： Yun-fei Wu Qing-hai Pang Zhi-jun He Teng-fei Song Wen-long Zhan Jun-hong Zhang School of Materials and Metallurgy University of Science and Technology Liaoning Anshan 114051 Liaoning China School of Metallurgical and Ecological Engineering University of Science and Technology Beijing Beijing 100083 China

In order to clarify the mutual effect between bituminite and anthracite in blends during industrial combustion, the influence of particle size and heating rate as well as oxygen concentration in atmosphere was analyzed. The results of non-isothermal thermogravimetric analysis indicated that the combustion behavior of blends was of great difference though blends were prepared with the same volatile content of 20%. The catalysis of bituminite to anthracite changed with the thermal and kinetic condition of combustion reaction, and consequently, blends with different collocations were suitable for various combustion environments. Superior combustion properties of some blends were achieved at high heating rates, while others might react faster under high oxygen-enriched atmosphere. Simultaneously, the volume model and unreacted core model as well as random pore model were introduced to fit the experimental data. The kinetic calculation results showed that the combustion of blends at different heating rates all agreed better with that of random pore model in comparison with the other two models, while the apparent activation energy of samples all decreased with the increase in heating rate. The similarity of functional group structure between bituminite and anthracite is closely related to the accordance in com-bustion stage of bituminite and anthracite in blends.

关键词： pulverized coal injection Coal blend Mutual effect Kinetics Activation energy Bituminite Anthracite

Experiment Research on Gasification Character of Pulve-rized Coal at Medium Temperature

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Energy and Power Engineering 2013年第4期5卷 315-318页

作者： Tong Lou Zhong-xiao Zhang Jun-jie Fan Hai-quan An Zhi-hao Zhou Pu-jie Yue College of Environment and Architecture University of Shanghai for Science and Technology Shanghai China College of Environment and Architecture University of Shanghai for Science and Technology Shanghai China School of Mechanical Engineering Shanghai Jiao Tong University Shanghai China School of Mechanical Engineering Shanghai Jiao Tong University Shanghai China

In this paper, effect of gasification temperature and residence time on gasification characteristics of typical pulverized coals under atmosphere pressure were studied on a one-dimensional electric heating drop tube furnace system to evaluate gasification characteristics of pulverized coal at medium temperature. The results show that the gasification rate increases with the raising of the gasification temperature under the temperature among 1150℃and1450℃, and as the temperature is above1350℃, the increasing rate become slower. Cold gas efficiency?and?carbon conversion meet the maximum value when the temperature approaches the ash fusion point of coal. With the further rise of the temperature, ash on the surface of the char starts to be melted,?the gasification reaction rate decreases, due to the hindrance of the effective contact between coal char and gasification agent. The gasification efficiency would become steady when the residence time exceeds 8s.

关键词： Gasification Characteristic pulverized Coal Carbon Conversion Cold Gas Efficiency