Hale Sutcu

Characterization and Combustion Kinetics of Chars Obtained from Loquat Stones

This paper describes the production of chars from loquat stones in a tube furnace at carbonization temperatures of 600°C, 700°C, and 800°C in a nitrogen flow at a heating rate of 10°C/min. The physical and chemical structures of the stones and chars were investigated by FTIR spectrometer, X-ray diffractometer, and SEM, as well as the combustion reaction and kinetic parameters based on the TG-DTG graphs obtained by thermogravimetric analysis. The combustion reaction was carried out at a heating rate 10°C/min and an oxygen flow rate of 50 ml/min up to 700°C. The kinetic parameters were calculated using the methods by Arrhenius; Coats and Redfern; Horowitz and Metzger; and Ingraham and Marier.

The Pyrolytic Characteristics and Kinetics of Agricultural Waste, Bituminous Coal, and Their Blends

This study investigates the pyrolytic characteristics and kinetics of bituminous coal, vine-trimming waste, and blends of these in varying proportions. The pyrolysis of the bituminous coal and vine-trimming waste was performed at heating rates of 5°C/min, 20°C/min, and 80°C/min under a nitrogen flow rate of 50 ml/min from ambient to 1000°C. Different blends containing 10%, 20%, 40%, and 50% vine-trimming waste were prepared and pyrolyzed at a heating rate of 20°C/min and a nitrogen flow rate of 50 ml/min from room temperature up to 1000°C. The reaction degrees and kinetic parameters were calculated using the Coats and Redfern kinetic model. The pyrolysis of bituminous coal and vine-trimming waste took place in two stages, and with increasing heating rate there was a decrease in the activation energies. In contrast, the pyrolysis of the blends occurred in two stages. The first stage involves decomposition of vine-trimming waste, and the second one that of bituminous coal. As the proportion of vine-trimming waste in the blend increased, there was a decrease in the activation energy in the first stage and an increase in the second stage.

Coal Desulfurization Using Natural Ca-Based Sorbents

Lignite with a high organic sulfur content was desulfurized by pyrolysis performed at temperatures ranging from 650 to 950°C. An investigation was carried out on the effect of calcium-based sorbents such as lime, limestone, and dolomite on removing sulfur during pyrolysis in the presence of N 2 and CO 2 gases. Limestone and dolomite proved more effective than lime and more sulfur was removed in an atmosphere of CO2 than in an atmosphere of N2.

The Removal of Sulfur from Dursunbey and İskilip Lignites in Turkey, Using Natural Trona: 1. The Effect of the Thermal Method

This article is concerned with removing the pyritic and total sulfur contents from Dursunbey and İskilip lignites by means of trona, which is a natural mineral. The experiments were performed at 20, 50, and 90°C for periods ranging from 15 to 180 minutes using trona solutions with concentrations in the 2.50–15.00% range, and the optimal conditions for sulfur removal were determined. The effect of variable temperature (20, 50, and 90°C), concentrations of distilled water (0%) and trona solution concentration (1.25–15.00%), and experimental duration (15–180 minutes) on sulfur removal was investigated under the optimal conditions determined. It has been established that trona affects sulfur removal in thermal atmosphere and it reduces the pyritic sulfur contents of Dursunbey and İskilip lignites by 41 and 31% and the total sulfur contents by 41 and 38%, respectively.

Effect of Hydroxides on Carbonization of Bituminous Coal

Adsorbents were produced from bituminous coal using chemical reagents such as KOH, NaOH, and LiOH. The effects of hydroxides on the structure of the adsorbents were established by means of iodine number analysis, BET surface analysis, thermogravimetric analysis (TGA), and Fourier Transform Infrared spectrum (FT-IR) analysis. It has been established that the BET surface area and iodine number values of the adsorbents are in the order of KOH > NaOH > LiOH.

Combustion kinetics of oil shales by thermogravimetric analysis

ABSTRACT This study investigates the combustion characteristics of oil shales obtained from two different regions and their blends prepared by mixing them in the proportions of 25, 50, and 75%. To this end, thermogravimetric analyses were performed at an air atmosphere flow rate of 100 ml/min and heating rates of 5, 10, 40°C/min. The kinetic parameters of combustion reaction were calculated using the Coats&Redfern kinetic model.ABSTRACTThis study investigates the combustion characteristics of oil shales obtained from two different regions and their blends prepared by mixing them in the proportions of 25, 50, and 75%. To this end, thermogravimetric analyses were performed at an air atmosphere flow rate of 100 ml/min and heating rates of 5, 10, 40°C/min. The kinetic parameters of combustion reaction were calculated using the Coats&Redfern kinetic model.

Structural characterization of oil shale occurring in Mengen, Turkey

This study deals with structural characterization of oil shale obtained from the township of Mengen in Bolu, Turkey by means of proximate analysis, ultimate analysis, FTIR spectrometry, XRF spectrometry and thermogravimetric analysis. Thermogravimetric analysis was employed to investigate pyrolysis of the oil shale samples at the heating rates of 5, 20, 40°C/min and the Coats and Redfern kinetic model to investigate their pyrolysis kinetics.This study deals with structural characterization of oil shale obtained from the township of Mengen in Bolu, Turkey by means of proximate analysis, ultimate analysis, FTIR spectrometry, XRF spectrometry and thermogravimetric analysis. Thermogravimetric analysis was employed to investigate pyrolysis of the oil shale samples at the heating rates of 5, 20, 40°C/min and the Coats and Redfern kinetic model to investigate their pyrolysis kinetics.

The Combustion Behavior of Eriobotrya japonica Stones

This article investigates the combustion characteristics and combustion kinetics of Eriobotrya japonica stones by thermogravimetric analysis. The combustion experiments were conducted at heating rates of 5 and 50°C/min in the presence of oxygen. The reaction degree, the activation energy, and the exponential factor of the combustion process were calculated by employing the Coats and Redfern kinetic model.

The Removal of Sulfur from Dursunbey and İskilip Lignites in Turkey, Using Natural Trona: 2. The Effect of the Microwave Radiation Method

This article describes the removal of pyritic and total sulfur contents of Dursunbey and İskilip lignites in microwave radiation atmosphere using trona, which is a natural mineral. Preliminary experiments were carried out aimed at determining optimum conditions using trona solutions with concentrations in the 2.50–15.00% range at microwave radiation powers of 90, 180, and 360 W for microwave radiation durations ranging from 30 to 480 sec. The effect of variables, such as distilled water (0%), trona solution concentration (1.25–15.00%), and microwave radiation power (90, 180, and 360 W), on sulfur removal was determined under optimal conditions. As a result of experiments conducted in microwave radiation atmosphere, the pyritic sulfur contents of Dursunbey and İskilip lignites were reduced by 48 and 38% and the total sulfur contents by 38 and 32%, respectively.

Prediction of Metallurgical Coke Strength from the Petrographic Composition of Coal Blends

Abstract Turkey, especially Zonguldak on the West Coast of Black Sea region, has large reserves of bituminous coal that can be used either directly or in blends with other coals for metallurgical coke production. It is possible to predict the coking properties of these coals by petrographic analysis. In this study, semi- and non-coking coals were blended with coking bituminous coals in varying proportions and an estimation was made as to their stability factors through petrographic techniques. It was established that semi- and non-coking bituminous coals could be used in the production of metallurgical coke.