Combustion and pyrolysis characteristics of tunçblek lignite

Journal of Thermal Analysis and Calorimetry, Mar 2006

In this study, thermal characteristics and kinetic parameters of cleaned Tunçbilek lignite were determined by using a Setaram Labsys DTA/TG/DSC thermal analysis system both for combustion and pyrolysis reactions. Experiments were performed at a heating rate of 10°C min–1 under reactive (air) and inert (nitrogen) gases up to 1000°C. Non-isothermal heating conditions were applied and reaction intervals were determined for combustion and pyrolysis reactions from obtained curves. The combustion properties were evaluation by considering the burning profile of the lignite sample. Burning temperatures and rate of combustion were determined from TG/DTG curves. Calorific value of the lignite sample was measured by DSC curve and compared with the adiabatic bomb calorimeter result. In addition to investigation of the combustion properties, pyrolysis characteristics of the lignite sample were investigated based on TG/DTG/DSC curves. Activation energy (E) and pre-exponential factor (A) were calculated from the TG data by using a Coats–Redfern kinetic model both for combustion and pyrolysis reactions of cleaned Tunçbilek lignite.

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Combustion and pyrolysis characteristics of tunçblek lignite

J. Therm. Anal. Cal. COMBUSTION AND PYROLYSIS CHARACTERISTICS OF TUNÇB LEK LIGNITE . Y. Elbeyli 0 1 S. Pi kin 0 1 0 Akadémiai Kiadó , Budapest, Hungary Springer, Dordrecht , The Netherlands 1 Department of Chemical Engineering, Y ld z Technical University , 34210 stanbul , Turkey In this study, thermal characteristics and kinetic parameters of cleaned Tunçbilek lignite were determined by using a Setaram Labsys DTA/TG/DSC thermal analysis system both for combustion and pyrolysis reactions. Experiments were performed at a heating rate of 10°C min-1 under reactive (air) and inert (nitrogen) gases up to 1000°C. Non-isothermal heating conditions were applied and reaction intervals were determined for combustion and pyrolysis reactions from obtained curves. The combustion properties were evaluation by considering the burning profile of the lignite sample. Burning temperatures and rate of combustion were determined from TG/DTG curves. Calorific value of the lignite sample was measured by DSC curve and compared with the adiabatic bomb calorimeter result. In addition to investigation of the combustion properties, pyrolysis characteristics of the lignite sample were investigated based on TG/DTG/DSC curves. Activation energy (E) and pre-exponential factor (A) were calculated from the TG data by using a Coats-Redfern kinetic model both for combustion and pyrolysis reactions of cleaned Tunçbilek lignite. combustion; kinetics; lignite; pyrolysis; thermal analysis Introduction Thermogravimetric analyses (TG) together with DTA or DSC are effective methods commonly used for quantitative determination of mass loss as a function of the gradual increase in temperature [ 1 ]. The methods play an important role in the investigation of thermal characteristics of mineral matters. Various methods such as thermogravimetric analysis (TG), differential thermal analysis (DTA), dynamic microcalorimetric analysis (DMA) and swelling index (SI) measurements have been developed to determine the thermal characteristics of coals. Thermal characteristics of coal change depend mainly on its chemical constituents, macerals, rank, grade, origin, etc. [ 2, 3 ]. Coal undergoes a series of complex physical and chemical changes during the combustion and pyrolysis. Combustion characteristics such as heat content, ignition and burn off temperatures and maximum rate of mass loss are of important in coal utilization and these features can be determined from the TG and DTG curves of the coal samples [ 4, 5 ]. Also, pyrolysis of coal is of important for beneficiation from coal due to being the first step in coal conversion processes like carbonization, liquefaction, combustion and gasification [6]. Previous studies on DTA/TG/DSC analysis of lignite and bituminous coals carried out under different experimental conditions. Results show that the thermal behaviour of coals depends on experimental * conditions such as particle size, sample amount, heating rate and gas flow rate. Pi kin et al. [ 7 ] investigated the thermal reactivities of five Turkish lignites (Elbistan, Ilg n, Karl ova, Kangal and Yata an) under air atmosphere and show the correlations between heat contents measured by DTA and calorific values of the coal samples measured by adiabatic bomb calorimeter. Kök et al. [ 8 ] investigated that combustion characteristics of lignite and oil shale samples by thermal analysis techniques and kinetic calculations performed for oxidation. Iordanidis et al. [ 1 ] investigated combustion properties and burning profiles of Greece lignites and they showed good correlations between results of proximate and calorimetry analyses and DTA/TG data. Arenillas et al. [ 9 ] determined by using the TG/DTA techniques that effects of coal blending on combustion characteristics. Kök et al. [ 10 ] determined that thermogravimetric characterization of ten lignites and kinetic calculation for their oxidation processes. Kök [ 11 ] carried out coal combustion experiments in air atmosphere up to 600°C at a heating rate of 10°C min–1 by using DSC and calculated the kinetic parameters beneficiation from Arrhenius and Coats–Redfern plots. In addition to combustion studies of coal by using TG/DTA/DSC, investigations of pyrolysis properties of bituminous coal and lignites have been studied by many investigators. Elder and Harris [ 12 ] investigated the thermal characteristics of Kentucky bituminous coals during pyrolysis in an inert atmosphere. They determined the exothermic reaction at a range of 300 to 500°C, where the major mass loss occurs and which has been associated with the primary carbonisation process and the development of a plastic state. Elbeyli et al. [ 13 ] investigated pyrolysis stages and kinetics parameters of some Turkish bituminous coals in nitrogen atmosphere up to 1000°C under non-isothermal condition by using TG/DTG methods. Sina [ 14 ] investigated the kinetics of Soma lignite in water vapor and inert atmosphere (nitrogen) and (...truncated)


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İ. Y. Elbeyli, S. Pişkin. Combustion and pyrolysis characteristics of tunçblek lignite, Journal of Thermal Analysis and Calorimetry, 2006, pp. 721-726, Volume 83, Issue 3, DOI: 10.1007/s10973-005-9995-z