Akademik Veri Yönetim Sistemi
JOURNAL OF THE FACULTY OF ENGINEERING AND ARCHITECTURE OF GAZI UNIVERSITY, cilt.34, sa.1, ss.79-88, 2019 (SCI-Expanded)
Coal liquefaction is one of the most advantageous approaches for effective utilisation of coal. Despite the fact that the first study has been done the 1950s, there is a great lack of literature on the kinetic and mechanism studies of coal liquefaction. In this study, four different liquefaction mechanisms including reversible and irreversible reaction steps were proposedak eklendi.for Zonguldak, Soma and Beypazan coals. Moreover, the suitability of the proposed mechanisms was determined by forming first order linear Discrete-time models with the experimental data. In addition, the reaction rate constants of proposed mechanisms were calculated using Kalman filter. The sum of the squared differences of the values calculated from the experimental data and the models was used to determine the most appropriate mechanism for liquefaction of the coals. The results of the study show that for Zonguldak, Soma, and Beypazan coals, the reaction rate constants from coal to oils are at least twice higher than that from coal to asphaltene and from coal to preasphaltene. In addition, models having parallel and reversible steps have been observed to better fit with the experimental data. The best tit for these coals was obtained with the model having both reversible; coal <-> preasphahene, coal <-> oil, preasphaltene <-> oil, and irreversible; coal <-> asphaltene, asphaltene <-> preasphaltene, oil <-> asphaltene reaction steps. As a result, it has been determined that not only the irreversible reaction steps but also the reversible reaction steps are important in coal liquefaction studies.