Studies on RTD and continuous culture (SCP) in cylindrical and tapered reactors

The performance of a tapered reactor for the continuous cultivation of bakers' yeast (SCP) from cane molasses has been compared with that of a conventional cylindrical reactor. It is found that the tapered reactor has less non-idealities (bypass and deadspace).Using the experimentally evaluated bypass and deadspace values, a model for predicting conversions of substrate (cane molasses), based on the RTD model proposed by Cholette and Cloutier has been developed. The experimental substrate conversions are found to match the model satisfactorily.List of Symbols D h^–1 dilution rate - E() exit age distribution function - K_s kg/m³ Monod's saturation constant - -r _sa kg/(m³ · h) rate of substrate utilization - S kg/m³ substrate concentration expressed as dextrose equivalent (DE) - S_a kg/m³ substrate concentration in active zone - S₀ kg/m³ initial substrate concentration - S/S₀ dimensionless substrate concentration - v_a dm³/h volumetric flow through active zone - v_b dm³/h volumetric flow through bypass stream - u_l dm³/h substrate feed rate - v_g dm³/min air-flow rate - V dm³ total working volume of the reactor - V_a dm³ volume of active zone in reactor - V_d dm³ volume of dead zone in reactor - X kg/m³ biomass concentrationGreek Letters fraction of bypass of feed, v_b/v_l - fraction of deadspace, V_d/V - dimensionless residence time - _m h^–1 maximum specific growth rate - h mean residence time, V/v_l