| The purpose of this work is to develop and model processes for reusing waste materials which are generated in quantities of several million tons every year. Various options such as gasification, liquefaction and pyrolysis are available for processing these waste materials. In this study, liquefaction of waste materials to clean transportation fuel is studied. The various options considered for reprocessing included coal coprocessing, high temperature liquefaction, and thin-film evaporation. The materials that were studied in this work include waste oil, waste grease, and waste plastic. The selection of a specific approach depends upon the material being processed and is also dictated by legislation and cost.; Coal coprocessing with waste petroleum materials achieves the purpose of economically upgrading, both the coal and the waste materials. Coprocessing of coal with waste grease and waste oil was studied. The effect of various process variables such as temperature, pressure, reaction time, coal loading, and grease loading on total conversion and selectivity were examined. Coal conversions were found to increase with increases in temperature, hydrogen pressure, reaction time, and grease loading. Coal conversions in excess of 90% were obtained during coprocessing, with conversions to oil of over 50%. The coal coprocessing kinetics were modeled mathematically. The model predictions for the coal conversions were found to be within {dollar}pm{dollar}3% of the observed values. The effect of multi-stage coal coprocessing on product yield, selectivity and quality was also studied. It was observed that multi-stage processing offered increased conversion, selectivity and better economics than single-stage processing. High temperature liquefaction of commingled post consumer plastics was carried out in tubing bomb microreactor at temperatures around 500{dollar}spcirc{dollar}C and 100 psig cold pressure. The formation of oils, gases and coke was monitored. The optimum reaction conditions for maximizing the liquid yield were obtained. To better understand the process, a reaction mechanism for the liquefaction of plastics is proposed. A thin-film evaporation process was designed in order to process fueloil/gasoline mixtures into value added products. The process was modeled using ASPEN PLUS and the operating map for the thin-film evaporator was obtained. In the last part of this study, a process has been developed for utilizing inorganic waste materials, such as mineral company waste, as effective antistripping agents in asphalt pavements to increase the bonding between the asphalt and the aggregate surface. Novel test methods for characterizing aggregates and antistripping agents were also developed as a part of this study. |
