Mustafa Versan Kok

Use of thermal equipment to evaluate crude oils

Abstract A Du Pont differential scanning calorimeter (DCS) and thermogravimetric analyzer (TGA) has been used to characterize the pyrolysis and combustion properties of two heavy crude oils. In pyrolysis runs, temperature ranges where distillation and visbreaking occur were identified. In combustion with air three different reaction regions were identified, known as low temperature oxidation, fuel deposition, and high temperature oxidation. DSC-TGA curves have also been used to determine the heat values and reaction parameters of crude oils.

Temperature-controlled combustion and kinetics of different rank coal samples

Differential scanning calorimetry (DSC) and thermogravimetry (TG/DTG) has been used to obtain information on the temperature-controlled combustion characteristics of seventeen coals of different origin from Thrace basin of Turkey. Experiments were performed in air atmosphere up to 600°C at a heating rate of 10°C min-1. The DSC/TG curves clearly demonstrate distinct transitional stages in the entire coal samples studied. Reaction intervals, peak and burn-out temperatures of the coal samples are also determined. Two different kinetic methods known as, Arrhenius and Coats-Redfern, were used to analyze the kinetic data and the results are discussed.

Comparative pyrolysis and combustion kinetics of oil shales

Abstract In this research, thermal characteristics and kinetic parameters of eight Turkish oil shale samples were determined by thermogravimetry (TG/DTG) at non-isothermal heating conditions both for pyrolysis and combustion processes. A general computer program was developed and the methods are compared with regard to their accuracy and the ease of interpretation of the kinetics of thermal decomposition. Activation energies of the samples were determined by five different methods and the results are discussed.

Effect of particle size on coal pyrolysis

Abstract This research comprises the effect of particle size on coal pyrolysis by thermogravimetry (TG/DTG). All the experiments were conducted at non-isothermal heating conditions with a heating rate of 10°C min−1. in the temperature range of 20–600oC, under nitrogen atmosphere. Different fractions of Cayirhan coal coal showed differences in TG/DTG curves, peak temperatures and residue values. The Arrhenius model is applied to determine the kinetic parameters from TG/DTG curves.

EFFECT OF CLAY ON CRUDE OIL COMBUSTION BY THERMAL ANALYSIS TECHNIQUES

AbstractThis research was aimed to investigate the role of clay on the combustion and kinetic behavior of crude oils in limestone matrix. For this purpose, simultaneous TG (thermogravimetry) and DTA (differential thermal analysis) experiments were performed at three different heating rates as 10–15 and 20°C min–1, respectively. A uniform trend of decreasing activation energies was observed with the addition of clay. It was concluded that clays surface area affects the values of Arrhenius constant, while it is the catalytic properties of clay, which lower the activation energies of all the reactions, involved in the combustion process.

Recent developments in the application of thermal analysis techniques in fossil fuels

In this review, application of thermal analysis techniques (differential scanning calorimetry, thermogravimetry, differential thermal analysis, etc.) for fossil fuel characterization and kinetics are reviewed between 2001 and 2006. The results presented clearly showed that thermal analysis applications are well-established techniques used in fossil fuel research area.

Coal pyrolysis: Thermogravimetric study and kinetic analysis

This research comprises the coal pyrolysis by thermogravimetry (TG/DTG). During the pyrolysis of the coal samples studied, gradual and continuous weight loss over the entire temperature range was observed. The weight loss below 210°C is related to the removal of moisture. The subsequent pyrolysis process as revealed by the corresponding DTG peak that is related to primary devolatilization, during which carbon, hydrogen, and oxygen compounds are released. Arrhenius-type kinetic model was used to determine the kinetic parameters and the results are discussed.

Catalytic Effects of Metallic Additives on The Combustion Properties of Crude Oils by Thermal Analysis Techniques

Differential scanning calorimetry (DSC) was applied to crude oil combustion in the presence and absence of metal chlorides. It was observed that in the presence of smaller ratios of metallic additives, the surface reactions were predominant and the catalyst did not affect the reactions much. Three reaction regions were identified as low temperature oxidation (LTO), middle temperature oxidation (MTO) and high temperature oxidation (HTO). Kinetic parameters of the reaction regions were determined with two different methods and the results are discussed.

Pyrolysis and combustion studies of fossil fuels by thermal analysis methods

Abstract Instances where differential scanning calorimetry, thermogravimetry and differential thermal analysis have been applied to study the pyrolysis and combustion behaviour of fossil fuels (peat, lignite, bituminous coals, anthracite, oil shales, crude oils, lignite-oil mixtures, etc.) are reviewed. The literature survey showed that thermal methods were important not only theoretically but also from a practical point of view.

Pyrolysis analysis and kinetics of crude oils

This research presents the results of an experimental study on the determination of pyrolysis behaviour and kinetics of six crude oils by differential scanning calorimetry (DSC) and thermogravimetry (TG/DTG). Crude oil pyrolysis indicated two main temperature ranges where loss of mass was observed. The first region between ambient to 400°C was distillation. The second region between 400 and 600°C was visbreaking and thermal cracking. Arrhenius-type kinetic model is used to determine the kinetic parameters of crude oils studied. It was observed that as crude oils gets heavier (°API decreases) cracking activation energy increases. Activation energy of cracking also show a general trend with asphaltene content.