Understanding the liquefaction mechanism of Beypazari lignite in tetralin with ultraviolet irradiation using discrete time models

ŞİMŞEK E. H., Gulec F., Akcadag F. S.

FUEL PROCESSING TECHNOLOGY, cilt.198, 2020 (SCI-Expanded) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 198
  • Basım Tarihi: 2020
  • Doi Numarası: 10.1016/j.fuproc.2019.106227
  • Dergi Adı: FUEL PROCESSING TECHNOLOGY
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, PASCAL, Aerospace Database, CAB Abstracts, Chemical Abstracts Core, Chimica, Communication Abstracts, Compendex, Environment Index, INSPEC, Metadex, Civil Engineering Abstracts
  • Anahtar Kelimeler: Coal liquefaction models, Kinetics, Ultraviolet irradiation, Discrete-time models, Kalman filter, DONOR-SOLVENT LIQUEFACTION, COAL-LIQUEFACTION, THERMAL LIQUEFACTION, PRODUCT DISTRIBUTION, TURKISH LIGNITES, HYDROGEN-DONOR, KINETICS, DISSOLUTION, DEPOLYMERIZATION, HYDROCRACKING
  • Ankara Üniversitesi Adresli: Evet

Özet

This study has proposed four different liquefaction models consisting of both reversible and irreversible reaction steps with three lumped parameters, asphaltenes, preasphaltenes, and oils, for the liquefaction of Turkish lignite (Beypazart-carrhart). The coal had been liquefied in tetralin using a solvent/coal ratio of 5/1 at four different ultraviolet irradiation light sources of 90, 120, 150, and 180 W. The validity of the proposed models is specified by first order linear discrete-time models with the experimental data. Furthermore, the reaction rates of the proposed liquefaction models are determined using a Matlab program with the use of Kalman filter. The validation of proposed models for the liquefaction of Beypazari lignite is defined using the sum of the squared differences of the models and experimental data. The results demonstrate that models which consist of reversible steps provide a better fit with experimental data compared to models consisting of irreversible steps. While the liquefaction step from reactive coal to oils demonstrates a maximum reaction rate constant of 2*10(-2)h(-1), the other steps from reactive coal to either preasphaltenes or asphaltenes show lower reaction rate constants, about 1*10(-2) h(-1). In addition to the fact that the formation of preasphaltenes and asphaltenes from reactive coal takes place slowly, a major proportion of the oils are formed directly from reactive coal.