In order to investigate the oxidation kinetics of gas coal at low temperatures, we derived a rate equation of oxygen consumption during low-temperature oxidation of gas coal and deduced an E-c equation, expressing the...In order to investigate the oxidation kinetics of gas coal at low temperatures, we derived a rate equation of oxygen consumption during low-temperature oxidation of gas coal and deduced an E-c equation, expressing the relation between active energy E and oxygen concentration c. The reaction order n and active energy E were calculated with this equation based on experiments of static oxygen consumption tests. In addition, we proved the rationality of the E-c equation using a kinetic compensation effect and obtained the isokinetic temperature Tc. The results show that： 1） the gas coal oxidizes easily with increasing temperature and the oxidation tends to be spontaneous at higher temperatures; 2） the oxygen concentration c affects oxygen consumption very much at lower temperatures but has only a small effect at higher temperatures; 3） the isokinetic temperature Tc was 127 ℃ which has been experimentally validated as the key turning point during low-temperature spontaneous combustion of gas coal.展开更多
The desolvation of erythromycin acetone solvate was investigated under non-isothermal conditions by a thermogravimetric analyzer. This paper emphasized the kinetic analysis of non-isothermal TG-DTA data by Achar metho...The desolvation of erythromycin acetone solvate was investigated under non-isothermal conditions by a thermogravimetric analyzer. This paper emphasized the kinetic analysis of non-isothermal TG-DTA data by Achar method and Coats-Redfern method to fit various solid-state reaction models, and to achieve kinetic parameters of desolvation. The mechanism of thermal desolvation was evaluated using the kinetic compensation effect. The results show that kinetics of desolvation of erythromycin acetone solvate was compatible with the mechanism of a two-dimensional diffusion controlled and was best expressed by Valensi equation. Corresponding to the integral method and the differential method, the activation energy of desolvation of erythromycin acetone solvate was estimated to be 51.26—57.11 kJ/mol, and the pre-exponential factor was 8.077×106 s-1—4.326×107 s-1, respectively.展开更多
基金financial support provided by the National Key Technology R&D Program during the 11th Five-Year Period (No. 2006BAK03B05)the National Natural Science Foundation of China (Nos.50534090, 50674090 and 50804047)+1 种基金the Research Fund of the State Key Laboratory of Coal Resources and Mine Safety, China University of Mining and Technology (Nos.08KF14 and SKLCRSM09X04)the Scien-tific Research Foundation of China University of Mining & Technology (No.2007A001)
文摘In order to investigate the oxidation kinetics of gas coal at low temperatures, we derived a rate equation of oxygen consumption during low-temperature oxidation of gas coal and deduced an E-c equation, expressing the relation between active energy E and oxygen concentration c. The reaction order n and active energy E were calculated with this equation based on experiments of static oxygen consumption tests. In addition, we proved the rationality of the E-c equation using a kinetic compensation effect and obtained the isokinetic temperature Tc. The results show that： 1） the gas coal oxidizes easily with increasing temperature and the oxidation tends to be spontaneous at higher temperatures; 2） the oxygen concentration c affects oxygen consumption very much at lower temperatures but has only a small effect at higher temperatures; 3） the isokinetic temperature Tc was 127 ℃ which has been experimentally validated as the key turning point during low-temperature spontaneous combustion of gas coal.
文摘The desolvation of erythromycin acetone solvate was investigated under non-isothermal conditions by a thermogravimetric analyzer. This paper emphasized the kinetic analysis of non-isothermal TG-DTA data by Achar method and Coats-Redfern method to fit various solid-state reaction models, and to achieve kinetic parameters of desolvation. The mechanism of thermal desolvation was evaluated using the kinetic compensation effect. The results show that kinetics of desolvation of erythromycin acetone solvate was compatible with the mechanism of a two-dimensional diffusion controlled and was best expressed by Valensi equation. Corresponding to the integral method and the differential method, the activation energy of desolvation of erythromycin acetone solvate was estimated to be 51.26—57.11 kJ/mol, and the pre-exponential factor was 8.077×106 s-1—4.326×107 s-1, respectively.
