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A Study of Pyrolysis of Charring Materials and its Application to Fire Safety and Biomass Utilization.

dc.contributor.authorPark, Won Chanen_US
dc.date.accessioned2008-08-25T20:54:06Z
dc.date.availableNO_RESTRICTIONen_US
dc.date.available2008-08-25T20:54:06Z
dc.date.issued2008en_US
dc.date.submitteden_US
dc.identifier.urihttps://hdl.handle.net/2027.42/60757
dc.description.abstractA theoretical and experimental study of pyrolysis of charring material applicable to fire safety and biomass utilization is presented in this thesis. This work is divided into three parts. In the first part, thermal decomposition and pressure generation in charring solids undergoing opposed-flow flame spread is numerically studied with a detailed physics-based model. The result indicates that the char density and product yields are functions of depth due to an insulating char layer. The characteristics of various simplifying model assumptions such as global reaction, infinite rate kinetics and no convective gas transport were examined. In the second part, a method of determining the pyrolysis temperature by enforcing mass and energy balance is proposed and validated by comparison with the decomposition kinetics model and the experiments. This pyrolysis temperature has the form of pyrolysis rate weighted average temperature for the entire charring process. Heat flux, sample size, heat of pyrolysis and kinetic parameters are the most important for determining an appropriate pyrolysis temperature. A non-dimensional correlation to determine an appropriate T_p was proposed. Excellent agreement between the pyrolysis front model using the correlation and experimental data of wood cylinder pyrolysis was achieved. Finally, pyrolysis of wood sphere is studied both experimentally and theoretically. Weight loss and temperatures of the sample were measured during the experiments. Center temperature showed two distinct thermal behaviors with endothermic and exothermic reactions. The numerical study revealed the following findings: (i) Contribution of secondary tar decomposition and lignin decomposition to the temperature peak are small. (ii) Exothermic intermediate solid decomposition is responsible for the temperature peak. (iii) The temperature plateau is caused by endothermic cellulose decomposition. Based on the experimental and numerical results, a novel wood pyrolysis model is proposed. The model consists of three endothermic parallel reactions producing tar, gas and intermediate solid, followed by exothermic intermediate solid conversion to char and exothermic tar decomposition to char and gas. A three-dimensional pyrolysis model for arbitrary geometry charring material was developed using front tracking method. The model was applied for wood sphere pyrolysis analysis and validated by comparison with the one-dimensional model.en_US
dc.format.extent5158494 bytes
dc.format.extent1373 bytes
dc.format.mimetypeapplication/pdf
dc.format.mimetypetext/plain
dc.language.isoen_USen_US
dc.subjectWood Pyrolysisen_US
dc.subjectCharring Materialen_US
dc.subjectPyrolysis Modelen_US
dc.subjectFlame Spreaden_US
dc.subjectBiomassen_US
dc.subjectLiquid Bio-fuelen_US
dc.titleA Study of Pyrolysis of Charring Materials and its Application to Fire Safety and Biomass Utilization.en_US
dc.typeThesisen_US
dc.description.thesisdegreenamePhDen_US
dc.description.thesisdegreedisciplineMechanical Engineeringen_US
dc.description.thesisdegreegrantorUniversity of Michigan, Horace H. Rackham School of Graduate Studiesen_US
dc.contributor.committeememberAtreya, Arvinden_US
dc.contributor.committeememberDriscoll, James F.en_US
dc.contributor.committeememberIm, Hongen_US
dc.contributor.committeememberWooldridge, Margaret S.en_US
dc.subject.hlbsecondlevelMechanical Engineeringen_US
dc.subject.hlbtoplevelEngineeringen_US
dc.description.bitstreamurlhttp://deepblue.lib.umich.edu/bitstream/2027.42/60757/1/wochpark_1.pdf
dc.owningcollnameDissertations and Theses (Ph.D. and Master's)


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