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Experimental And Theoretical Study On The Cleaning Combustion Of Fujian Anthracite In CFB Boiler

Posted on:2006-01-03Degree:DoctorType:Dissertation
Country:ChinaCandidate:H Z HeFull Text:PDF
GTID:1102360185987853Subject:Engineering Thermal Physics
Abstract/Summary:PDF Full Text Request
Taking Longyan coal-a typical Fujian anthracite as an example, these factors which effect on the clean combustion of Fujian anthracite , especially its burnout in CFB boiler, was experimentally and theoretically studied in this paper. The research includes the following five parts of contents: (1) An introduction on the research background and an overview of correlative studies; (2) Study on the particle of typical Fujian anthracite and its combustion characteristics ; (3) Fly ash of CFB boiler burning Fujian anthracite and its residual carbon analyzed; (4) Clean combustion of Fujian anthracite in CFB boiler-effect of running character & operating parameter; and (5) Char particle combustion -Theoretical analysis and simulation;The research background was introduced at the beginning of this paper. Character of CFB boiler burning Fujian anthracite and some of the related running problems were analyzed, an overview was cast on the study of these factors such as coal property, coal combustion characteristics and running character of boiler which can effect on the burnout of anthracite, specially, the research on the thermal fragmentation of anthracite during combustion in fluidized bed combustor was also summarized.For the study of the combustion characteristics of Longyan coal, the flotation method was used to separate the different lithotypes from feeding coal, and particles with different size and density were obtained. By proximate and ultimate analysis, petrographical analysis, Scanning Electronic Microscope analysis, Mercury Porosimeter analysis, TG analysis and pilot scale fluidized bed combustion experiment, the combustion characteristics and particle properties of Longyan coal with different lithotype were studied, including the surface figure and pore structure of particle, the maceral content, the ignition and burnout temperature, and the reactivity, ect. Furthermore, the thermal fragmentation properties of Longyan anthracite particle with different lithotypes during pyrolysis and combustion were measured respectively in a thermobalance and pilot-scale fluidized bed reactor, the reason of fragmentation during combustion in CFB was analyzed, the fragmentation characteristics and those factors which influence the result of fragmentation were studied, and the variation of fragmentation with combustion time was also discussed.Using dates obtained from TGA experiment, the reaction kinetics parameters of Fujian anthracite was studied. These thermoanalysis tools such as Freeman-Carroll differential method, improved Coats-Redfern integral method and Flynn-Wall-Ozawa method were introduced to calculate the kinetic parameters of reaction. The effect of these factors such as the thermoanalysis method used, the heating rate in TGA experiment chosen, and the correlative reaction area selected on the kinetics parameters correlated were discussed, the authenticity of the kinetic parameters calculated from these different thermoanalysis method was analyzed and the kinetics parameters of 3 kinds of Fujian anthracite were correlated.Variation of the reactivity of char with time for Fujian anthracite during...
Keywords/Search Tags:Fujian Anthracite, Particle Properties, Combustion Characteristics, Fluidized Bed Combustion, Thermoanalysis, Circulating Fluidized Bed Boiler, Operating parameters, Burnout
PDF Full Text Request
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