Pyrolysis characteristics of Turkish lignites in N-2 and CO2 environments

Avşaroğlu, Sevil
Yozgatlıgil, Ahmet
Atımtay, Aysel
Pyrolysis characteristics and kinetic parameters of two Turkish lignites having different ash contents (Orhaneli as low ash and Soma as high ash sample) were studied under N-2 and CO2 atmospheres by means of thermogravimetric analysis. The isoconversional kinetic methods of FlynnWallOzawa, KissingerAkahiraSunose, and Friedman were employed to estimate the activation energy and pre-exponential factors. The experiments were conducted at four different heating rates of 5, 10, 15, and 20 degrees C/min within the temperature range of 50950oC. The obtained results indicated that changing the pyrolysis ambient had no significant effect on the devolatilization region up to 700 degrees C. The char formation region in N-2 atmosphere was due to the CaCO3 decomposition and was more significant for Soma lignite due to its high ash content. However, in CO2 atmosphere, the gasification reaction took place at temperatures higher than 700 degrees C. The decomposition process of CaCO3 in CO2 atmosphere was hampered up to temperatures higher than 900 degrees C. The estimated activation energies were found to have approximately similar trends under different atmospheres. For Orhaneli lignite, the average activation energy values were higher in CO2 environment. However, for Soma lignite due to decomposition of CaCO3,the activation energy values were higher in N-2 atmosphere. The mean uncertainty values were assessed for the activation energy values obtained for all test cases.


Pyrolysis, combustion and gasification studies of different sized coal particles using TGA-MS
Jayaraman, Kandasamy; Kök, Mustafa Verşan; Gokalp, Iskender (2017-10-01)
In this research, thermogravimetric and mass-spectrometric (TG-MS) analysis and kinetics of different sized (60 mu m,800 mu m, and 3 mm) Saray (Turkish origin) coal is examined at various combustion temperature ranges. Experiments are performed at the heating rate of 40 degrees C/min in an argon atmosphere up to combustion/gasification temperatures (850-1150 degrees C), which, is close to the conditions of fluidized bed systems for high ash coal applications. The combustion tests are performed at isothermal...
TGA and kinetic study of different torrefaction conditions of wood biomass under air and oxy-fuel combustion atmospheres
Barzegar, Ramin; Yozgatlıgil, Ahmet; OLGUN, HAYATİ; Atımtay, Aysel (2020-06-01)
Combustion and oxy-fuel combustion characteristics of torrefied pine wood chips were investigated by Thermogravimetric Analysis (TGA). Three torrefaction temperatures (250, 300, and 350 degrees C) and two residence times (15 and 30 min) were considered. Experiments were carried out at three heating rates of 10, 20, and 40 degrees C/min. The isoconversional kinetic methods of FWO, KAS, and Friedman were employed to estimate the activation energies. The assessment of uncertainty in obtaining the activation en...
BUTTINELLI, D; LAVECCHIA, R; POCHETTI, F; Geveci, Ahmet; GURESIN, N; Topkaya, Yavuz Ali (1992-10-01)
A composite mixture of three typical Cu/Zn complex ores, namely black-, yellow- and altered-ore, from Cayeli deposit in Turkey, was used for leaching experiments under atmospheric pressure in ferric sulphate solutions, In order to study the reaction kinetics of the copper and zinc dissolution in the temperature range from 50 to 80-degrees-C; also in the presence of a solvent for elemental sulphur, such as CCl4.
Kinetics of biological hydrogen production by the photosynthetic bacterium Rhodobacter sphaeroides O.U. 001
Koku, Harun; Gündüz, Ufuk; Türker, Lemi (2003-04-01)
The kinetics and the effects of various parameters on hydrogen production by Rhodobacter sphaeroides O.U. 001 were investigated in a batch column photobioreactor. In particular, the effect of the inoculum age and the implementation of a light-dark cycle illumination scheme for emulating natural sunlight have been investigated in detail. The possibility of using yeast extract to replace the rather expensive vitamin mixture in the medium was also studied. The results show that hydrogen production is decrease...
Application of TGA-MS technique for oil shale characterization and kinetics
Kök, Mustafa Verşan; Varfolomeev, Mikhail A.; Nurgaliev, Danis K.; Kandasamy, Jayaraman (2022-03-01)
Thermal characteristics and model free kinetics of four different oil shale samples were studied using simultaneous thermogravimetry-mass spectrometer (TGA-MS) analysis performed at three different heating rates and under air atmosphere. All the reaction regions and corresponding peak temperatures, mass loss, and the residue of oil shale samples were determined. Meanwhile, the main volatile products, primary alcohols, and aromatic compounds as products of oil shale combustion, were determined on the basis o...
Citation Formats
R. BARZEGAR, S. Avşaroğlu, A. Yozgatlıgil, and A. Atımtay, “Pyrolysis characteristics of Turkish lignites in N-2 and CO2 environments,” ENERGY SOURCES PART A-RECOVERY UTILIZATION AND ENVIRONMENTAL EFFECTS, pp. 2467–2475, 2018, Accessed: 00, 2020. [Online]. Available: