Transactions of the ASABE Vol. 63(4): 1019-1036 © 2020 American Society of Agricultural and Biological Engineers ISSN 2151-0032 https://doi.org/10.13031/trans.13565 1019 MINIATURE BIOMASS CONVERSION UNIT FOR LEARNING THE FUNDAMENTALS OF HETEROGENEOUS REACTIONS THROUGH ANALYSIS OF HEAT TRANSFER AND THERMOCHEMICAL CONVERSION J. B. Gartner, O. M. Reynolds, M. Garcia-Perez, D. B. Thiessen, B. J. Van Wie HIGHLIGHTS  A miniaturized thermochemical conversion system has been designed, manufactured, and optimized.  Five laboratories can be performed with the system, incorporating heat transfer and reaction engineering phenomena.  Educational materials to deploy the system in the classroom, including worksheets and solutions, are provided.  Pyrolysis, combustion, and gasification exercises are shown with reaction visualization and product validation. ABSTRACT. We describe a simple new miniaturized thermochemical module (MTM). Special considerations are needed to make the MTM useful not only for studying biomass conversion but also for providing safe classroom learning opportunities for heat and mass transfer and heterogeneous reaction engineering students and for training new researchers. The MTM consists of a quartz reactor wrapped with a Kanthal resistance wire and a silvered concentric annular glass shield for retaining thermal energy, placed in a protective Plexiglas viewing case. Safety is considered for use by new research train- ees and within the classroom. We demonstrate MTM usage through five laboratory exercises beginning with an experimental design to determine operating modes to establish thermochemical conversion temperatures. Heat transfer skills are devel- oped with the aid of a first-order differential heat transfer model and fractional factorial design. Thermochemical conver- sion is demonstrated and products are validated for pyrolysis, gasification, and combustion. The combustion laboratory also offers significant insight into reaction versus mass transfer-controlled regimes and for modeling heat transfer. Discus- sion is provided on the utility of the system for demonstrating heat transfer, kinetic, and mass transfer concepts, with appli- cations across the engineering curriculum. Keywords. Combustion, Education, Gasification, Heat transfer modeling, Miniature thermochemical module, Pyrolysis. here is a need to overcome the technical challenges to make miniaturized, visual, and safe hands-on STEM education equipment (Feisel and Rosa, 2005). Although there are excellent classroom heat transfer modules (Golter et al., 2005, 2016), those available for thermochemical biomass conversion are limited. Such modules should provide the opportunity to study pyrolysis, gasification, and combustion and be useful as research train- ing tools for thermochemical processes, research best prac- tices, and precautionary safety measures. These systems must be affordable so that several can be obtained and used by small groups for observation, constructing understanding, and testing hypotheses. Thermochemical conversion proceeds over a range of conditions. Under inert conditions, torrefaction occurs at 200C to 300C, reducing moisture and volatile content and resulting in a blackened product more suitable for bio-oil production via pyrolysis (Chen et al., 2003), while carbon concentrated biochar and bio-oils are formed at >700C (Ah- mad et al., 2016; Brown, 2003; Filippis et al., 2015; Fisher et al., 2012). In the presence of oxidizing agents at 700C to 900C, gasification of biochar produces synthesis gas (syn- gas), which is convertible to fuel-grade hydrocarbons via Fisher-Tropsch reactions (Tijmensen et al., 2002). Compo- sition varies dramatically with the fuel used in thermochem- ical conversion with regard to O 2 equivalence ratio (ER) and with the means for conducting such processes with regard to temperature (Hashemi et al., 2016; Mahinpey and Gomez, 2015; Son et al., 2011; Venkitasamy et al., 2011; Werle, 2015), residence time, oxidizing agent (Chen et al., 2003), Submitted for review in June 2019 as manuscript number EOPD 13565; approved for publication as a Research Article by the Education, Outreach, & Professional Development Community of ASABE in March 2020. The authors are Jacqueline B. Gartner, Assistant Professor, School of Engineering, Campbell University, Buies Creek, North Carolina; Olivia M. Reynolds, Graduate Student, The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, Washington; Manuel Garcia-Perez, Associate Professor, Department of Biological Systems Engineering, Washington State University Tri-Cities, Richland, Washington; David B. Thiessen, Clinical Assistant Professor, and Bernard J. Van Wie, Professor, The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, Washington. Corresponding author: Bernard J. Van Wie, 1595 Stadium Way, P.O. Box 646515, Washington State University, Pullman, WA 99164-6515; phone: 509-335- 4103; e-mail: bvanwie@wsu.edu. T