(61e) Chem-E-Car Experiments in Unit Operations Laboratory

Recently, the Chem-E-Car Competition has become a signature event of the annual AIChE student conference. It has become a fun-filled activity with an increase in participation by a wide number of AIChE Student Chapters. However, this ample opportunity has not been exploited as a teaching tool to demonstrate chemical engineering principles. For example, one could demonstrate simple concepts such as estimating gas pressure for the acetic acid/baking soda reaction (a popular reaction used in Chem-E-Cars) or determining the rate of reaction. The competition can also be used as a tool to enhance technical writing skills, apply reactor design methods, perform energy and mass balance calculations, estimate costs, and apply team management skills. In this regard, a new experiment was developed at OSU in the Unit Operations Laboratory using a Chem-E-Car. A model car was built using transparent PVC to facilitate easy visualization of the process. Further, the car was designed with interchangeable wheels and nozzles to accommodate experiments demonstrating fluid mechanics. A pressure transducer was installed to continuously acquire the transient changes in pressure using a computer. In addition, a pressure relief valve was placed on the model to demonstrate safety principles. Using the acetic acid/baking soda reaction, students (a team of three) were asked to develop a relation between the amounts of reactants and the total pressure. When the reactants were mixed, the system appeared to attain an equilibrium pressure as more CO2 was released with the venting of gas. Students were asked to perform detailed material and energy balances accounting for the solubility of CO2 in water, which could vary with the total pressure. Further, they were asked to check the effect of changing the nozzle diameter on the decreasing pressure. This low-cost experiment not only reinforces the concepts of thermodynamics but also prepares the students for safe engineering practice. Implications of this experience and a number of other possible experiments will be discussed in detail.