Pyrolysis of Biomass to Bio-oil in the Classroom: The fabrication and optimization of a miniaturized Biomass Conversion Module

This work-in-progress paper focuses on the fabrication and optimization of a miniaturized fast pyrolysis module for hands-on learning of biomass to biofuels conversion in the classroom. Our goals are to help engineering students better understand thermochemical conversion concepts including the specific reactions in pyrolysis, the process of optimizing a system, and the constraints of a system designed for pyrolysis. The modular design focuses on optimizing the temperature in the reactor by adjusting the energy delivered to the reactor by the resistance wire. In order to achieve pyrolysis temperatures, the length and type of the wire had to be optimized to get the reactor up to temperature. In this study we tested wires of Kanthal 145 alloy and tungsten and varied wire length for optimization. We studied different combinations of these two variables, including varying the wire length from 10 – 45 cm with both types of wire. These variables changed the amount of current delivered to the system, which changed the final temperatures with each combination. Understanding the interactions between current delivery and wire type is critical for achieving reactor pyrolysis temperatures. Temperature plots were analyzed to determine how changing wire type and wire length affect reaction rate and speed at which final temperatures are reached. Qualitative data were also collected to determine how changing the reactor wire length and wire type affected the volume of bio-oil produced. Based on the experimental design, we expected to find an optimal wire length and choose between the better wire type to achieve desired pyrolysis temperature and reaction time so that pyrolysis liquid produced is consistent with literature results where 75% of the biomass weight is converted to pyrolysis liquid with only 12% of the initial biomass weight being converted to water. This design process optimization is expected to lead to a modular system useful in the classroom for communicating reactor design principles and teaching students about optimization of a reactor system with respect to both temperatures achievable and bio-oil yield .