(159g) Effect Study of Operating Conditions and Optimization of Gas Holdup in a Bubble Column Reactor

Bubble columns are multiphase reactor where the gas phase is dispersed into a continuous liquid phase in two-phase columns .In particular, BCR's are widely used in petrochemical, biochemical and chemical industries owing to their advantages in both operation and system design. The hydrodynamics phase mixing, and transports which may affect the performance of BCR remains difficult to predict due to the complex phase interactions and flow turbulence. In the present work an air-C9C11 system selected to mimic the physical properties in a real BCR. The experimental system was designed and constructed with best form to obtain reliable data. The effects of gas velocity U_g and system pressure P on gas hold up H_g and liquid hold up H_l were studied in a 0.162 m diameter and 2.5 m height. The velocity was measured by sophisticated flow meter, while pressure was monitored by smart transducer. The radial distributions of phase hold-up were investigated under different operating conditions.2-D and 3-D styles for profiles of gas hold-up and liquid hold-up were showing conflicted trend between them under similar operating conditions. Stacked form of profiles was explained the interface between phases. U_g is a crucial operating variable in the BCR, which greatly affects the hydrodynamics and flow regimes. H_g increased with U_g, and the liquid holdup H_l had the opposite trend. Operating pressure p is one of the key factors affecting the hydrodynamics in BCR. An increase in P results in smaller bubbles. As a result, H_g increases because of the longer residence of the smaller bubbles in the reactor.The churn-turbulent flow has proven the best flow regime to collect data and formulating of model because of it's characterized of highly-agitated flow and good mixing. Development of characteristics study for BCR has required simulating of the process variables by global mathematical model. The objective is H_g while the selected effective decision variables are U_g and P .Optimization technique is powerful tool to guide the experimental work for best operating conditions. This was reduced the risk of experimental runs and the consumed cost for design and operating. LINGO has proven the efficient comprehensive tool for solving nonlinear model of multi-phase BCR. Deterministic nonlinear search (NLS) appeared a weakness of the simulated model and was guiding the software for best executing. 3-D surface form was explained several local optimal values of H_g.The global optimal H_g is 0.48 at U_g=0.38 m/s and P=0.66Mpa.Reasonable agreement have obtained when compared the simulated results with the experimental data.