Kinetic study of coal extraction by tetralin with ultrasonic irradiation

This investigation was concerned with the kinetics of coal extraction by 1,2,3,4-tetrahydronaphthalene (tetralin) under the influence of ultrasonic waves. The coal used in this study was obtained from the working face of the Utah Spring Canyon Mine. The extraction of coal has been carried out at five different temperatures: 24° G, 29°C, 34*C, 44°C, and 54°C. At each of these temperatures the yield of extract increases rapidly in the early stages of extraction, levels off later to approach an asymptotic value. Analysis of the data from this study showed that a modified firstorder rate equation best describes the kinetics of the extraction process. In this study on the solvent extraction of coal, the enthalpy of activation (6.0 kcal/mole) was found to remain constant throughout the extraction process. However, an increase in free energy of activation ) that was observed is accounted for by a decrease in entropy of activation. The values of free energy of activation were found to be 24»5 kcal/mole during the early stages of the extraction process and 25.1 kcal/mole near the end of the extraction process. An experiment was conducted to see if tetralin undergoes decomposition when subjected to ultrasonic irradiation for 20 hours. The results show that no significant decomposition of tetralin occurs during the first 15 hours under ultrasonic irradiation and less than one percent of the tetralin was found to be decomposed at the end of 20 hours.