Desenvolvimento e caracterização de um reator tubular (PFR) de bancada por distribuição de tempo de residência

Abstract

The study of Residence Time Distribution (RTD) is essential for understanding the hydrodynamic behavior of chemical reactors, especially those intended to approximate plug flow reactor (PFR) behavior. However, many teaching laboratories lack simple and affordable equipment that allows these phenomena to be observed in practice, creating a gap in students’ experimental training. This work aimed to design, build, and evaluate a bench-scale PFR using low-cost materials, enabling the experimental analysis of RTD via pulse perturbation. Water was used as the working fluid, and tartrazine was employed as a tracer, injected instantaneously. Five experimental runs were conducted, varying the flow rate (75-100 mL.min−1), tracer concentration (2000-4000 ppm), the presence of geometric constrictions, and the injection position. The collected samples were analyzed by UV-Vis spectrophotometry, allowing the determination of the C(t) and E(t) curves and the calculation of hydrodynamic parameters such as space time ( ), mean residence time (tm), variance 2, and skewness s3. The results showed good agreement between and tm under the most stable conditions, with percentage differences on the order of 1-3%, indicating behavior close to plug flow. Conversely, the introduction of geometric constrictions and changes in the injection position led to increased variance and greater asymmetry of the E(t) curves, evidencing axial dispersion and deviations from the ideal model. Thus, the bench-scale reactor demonstrated sensitivity to operating conditions and quantitative suitability for RTD analysis, confirming its potential as a didactic tool for teaching reactor engineering.