| The pilot-scale production of the thermally stable coal-based jet fuel, so-called JP-900, has recently been performed using coal-derived liquids and a blend of coal-derived liquids with petroleum refinery streams. The hydrotreatment and dearomatization of light cycle oil (LCO) and refined chemical oil (RCO) were selected processes for the production of thermally stable compounds. Up to now, three generations of coal-based jet fizels have been produced in pilot plants and their thermal stability properties have been tested under static and dynamic conditions in autoxidative and pyrolytic regimes.; To study the relationships among chemical composition, solid deposition rate and other physical properties, mathematical models were established using multiple linear regression (MLR) and artificial neural network (ANN) approaches. ANN is more effective than MLR, as it can establish non-linear relationships of complex systems and can also accurately predict unseen data sets. For visualization purposes, the ternary diagrams have been used to display relationships among three main components with properties. An optimum chemical composition was developed to meet requirements of slow solid deposition rate, net heat of combustion at 18400 Btu/lb and smoke point at 19 mm. Based on the existing data, the 1:1 blend of saturated LCO and saturated RCO, composing 0.76% aromatics, 68.47% cycloalkanes (46.98% decalin and 21.49% other cycloalkanes) and 30.77% alkanes and the others, is the only sample having chemical composition that can meet all requirements. However, coal-based jet fuels which are composed of large amounts of aromatics, tetralins or decalins can still be desirable JP-900 if the limitations on aromatics, net heat of combustion and smoke points are flexible.; Finally, the correlations between hydrogen structures of coal-based jet fuels and solid deposition rate have been created using MLR and ANN. These correlations are statistically, physically and chemically satisfied. It was found that the structures of hydrogen donors in decalin, tetralin and indane are the main contribution to suppression of solid deposition. Based on this structure-thermal stability relationship, reaction mechanisms of pyrolytic degradation of coal-based jet fuels have been proposed. (Abstract shortened by UMI.)... |
