Particle size effect on the oxidation mechanism of lignites

1999-09-27
In this research, effect of particle size on the oxidation mechanisms of Cayirhan, Tuncbilek and Soma lignites are studied. Non-isothermal thermogravimetry and derivative thermogravimetry (TG/DTG) experiments were carried out for 12 different size fractions. Data obtained from TG/DTG experiments are converted into dimensionless time (instantaneous size/original size) versus dimensionless time (time/burn-out time) to show the progress of oxidation mechanisms of lignites, It was found that lignites show linear behaviour at elevated temperatures, which justifies the assumption that chemical reaction is the controlling step.
Thermochimica Acta

Suggestions

Catalytic oxidation of nitrogen containing compounds for nitrogen determination
Karakaş, Gürkan (2019-02-15)
The high temperature catalytic oxidation (HTCO) performance of Al2O3 supported Pt, Cu, Cu-Ce and Fe catalysts were systematically studied with a perspective of selective oxidation of nitrogenous compounds to nitric oxide for quantitative determination of bound nitrogen. The catalyst samples were prepared via impregnation and characterized by XRD and BET. In addition, temperature programmed reaction experiments with acetonitrile and oxygen were conducted to evaluate the catalytic activity and selectivity tow...
Activity Comparison of MCM-41 and V-MCM-4 Catalysts for Ethanol Selective Oxidation and DRIFTS Analysis
Gucbilmez, Yesim; Doğu, Timur; BALCI, FATMA SUNA (2009-01-01)
The activity of a V-MCM-41 catalyst with a V/Si molar ratio of 0.04 was compared with the activity of a pure MCM-41 catalyst and some DRIFTS studies were performed in order to understand the mechanism of selective oxidation of ethanol. V-MCM-41 was found to be much more active than pure MCM-41, favouring the formation of high amounts of ethylene over 300 degrees C. MCM-41, on the other hand, was found to favour the formation of acetaldehyde over ethylene at all studied temperatures. It was shown by reaction...
Nanostructure of montmorillonite barrier layers: A new insight into the mechanism of flammability reduction in polymer nanocomposites
Isitman, Nihat Ali; Kaynak, Cevdet (2011-12-01)
This study describes the mechanism of flammability reduction in flame-retarded polymer matrix organo-montmorillonite reinforced nanocomposites. Morphologies of untested polymer nanocomposites and char residues formed by combustion in the mass loss calorimeter are characterized by XRD and TEM techniques. It is postulated that a combination of well-dispersed montmorillonite platelets and flame retardants in the polymer matrix provides nano-structured char formation. Initial montmorillonite dispersion in flame...
Effect of particle size on the thermal and combustion properties of coal
Kök, Mustafa Verşan; Hiçyilmaz, C.; Karacan, Ö. (1997-10-22)
In this research effect of particle size on the combustion properties of Cayirhan coal sample was studied. Non-isothermal thermogravimetry and derivative thermogravimetry (TG/DTG) experiment were carried out for twelve different size fractions of the Cayirhan coal sample. Thermogravimetry experiments were performed from ambient to 900 degrees C in air atmosphere. Differential thermogravimetric data were analysed using an Arrhenius type reaction model assuming a first-order reaction. Kinetic parameters of th...
Thermal, kinetics, and oxidation mechanism studies of light crude oils in limestone and sandstone matrix using TG-DTG-DTA: Effect of heating rate and mesh size
Varfolomeev, Mikhail A.; Nurgaliev, Danis K.; Kök, Mustafa Verşan (2016-01-01)
This research was focused on the combustion kinetics and oxidation mechanisms of light crude oils in limestone and sandstone matrices. Similarity of the TGA-DTA curves was produced for different crude oils + limestone or sandstone mixtures indicates that the crude oil undergoes three major transitions, known as low-temperature oxidation, fuel deposition, and high-temperature oxidation when subjected to an oxidizing and constant rate environment. Kinetic analysis of the low- and high-temperature oxidation re...
Citation Formats
M. V. Kök, “Particle size effect on the oxidation mechanism of lignites,” Thermochimica Acta, pp. 121–125, 1999, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/42606.