2023 ASEE Annual Conference & Exposition

Students entering the chemical engineering field are introduced to block flow diagrams (BFDs), a new type of pictorial representation of a chemical process that can prove difficult to interpret for novices. Block flow diagrams typically include a wide range of data types and process steps with unique functions. It is essential that students are able to make sense of these diagrams to construct an understanding of the chemical and physical processes at play. In the education literature, sensemaking typically involves building a relationship or analogy between a concept and a scenario in the real world. We describe how upper- and lower-level undergraduate chemical engineering students make sense of simple BFDs depicting the synthesis of tetrachloroethylene from carbon tetrachloride. Analysis of our think-aloud interviews with students as well as analysis of written responses revealed a four-stage cyclic structure that students followed when carrying out the sensemaking of the BFDs. The four-stage cyclic structure involved forming a surface-level understanding of the diagram, connecting the diagram to chemical reactions, evaluating the design, suggesting improvements and justifying. We found that the upper- and lower-level students took primarily the same approach to make sense of the process, but greater distinctions emerged upon breakdown based on industrial experience. Students who have had internship experience in industry were able to use their experience and knowledge of other factors such as space and cost to approach the problem differently. This work can provide insights for instructors who are teaching process flow diagrams on how to help students make better sense of PFDs.