We designed a packed bed reactor (PBR) experiment for the Unit Operations Laboratory course to expand reactor-based instruction beyond existing batch and CSTR configurations, addressing limited student exposure to gas-liquid mass transfer and plug-flow behavior.
We selected a reactive absorption system using CO₂ and NaOH for its low-cost reactants, familiar laboratory handling, and fast, well-studied kinetics suitable for repeated student trials. The design treated CO₂ removal as a coupled absorption-reaction process in which CO₂ dissolves into the liquid phase and reacts with hydroxide to form bicarbonate/carbonate species— making overall performance dependent on gas-liquid mass transfer and hydrodynamics.
We specified countercurrent gas-liquid operation, instrument locations, and key control points via a draft process flow diagram, including temperature, pressure drop, and inlet/outlet composition monitoring to support future conversion and mass-transfer calculations. Equipment scope covered column sizing, packing, pumps, flow meters, piping, and planned integration of temperature probes, pH meters, and CO₂ analyzers.
MATLAB and Aspen Plus supported sizing, sensitivity checks, and consistency verification across key operating variables: gas flow rate, liquid circulation rate, NaOH concentration, and temperature. Experimental operation over 25–65°C and CO₂ flow rates of 250–1000 L/min showed improved removal at higher temperatures, with best performance near 500 L/ min. Predictive models for outlet pH, CO₂ concentration, and temperature effects matched experimental results within 5–20% error.