Investigation of the Liquefaction Kinetics of the PolyE-IL-Catalyzed Catalytic Thermo Liquefaction Process for Organic Biodegradable Municipal Solid Waste

The catalytic thermo liquefaction (CTL) process with integration of the PolyE-IL catalyst has the specific advantages of high conversion, no char production, and nonstringent operating conditions. However, the study of the liquefaction kinetics is one of the most important parameters to elucidate the mechanism of the CTL process and a guide for process scale-up. The present manuscript demonstrates the elucidation of the liquefaction kinetics of a PolyE-IL-catalyzed CTL process for CTL of organic biodegradable waste. The CTL for different feedstocks showed >80% feed conversion at 120 °C in 120 min and under 10 bar inert gas pressure. Thus, both pressure and reflux reaction condition approaches for CTL were followed to investigate prevailing reactor parameters for liquefaction. However, the influences of reactor operating conditions with variable MSW slurry concentrations, temperatures, and times were inspected. The lower slurry concentration (<3 wt %) did not show the effect of the mode of operation, but the efficacy of liquefaction was reduced in the reflux mode of operation at a higher slurry concentration (<5 wt %). The reaction temperature of >90 °C was found to be efficient to achieve a maximum conversion, 75 and 70% at pressure and reflux modes of operation, respectively. Moreover, it was observed that a reaction time of at least 10 min was sufficient to achieve at least 75% conversion, although a longer reaction time increased the degree of liquefaction. According to liquefaction behavior of MSW, the plausible reaction routes were proposed. The first-order reaction was shown in the kinetic analysis to have an activation energy of 411.5 J/g and a frequency factor of 9.3 min-1. The lowest contact time was advantageous for increased liquefaction of MSW. Thus, the present study offers an in-depth understanding of the CTL reaction pathways and the liquefaction kinetics, which can be useful for developing scalable and economically viable CTL processes.