Fig. 11

Comparison of enzyme requirements for batch and countercurrent saccharifications at various batch residence time and glucose concentrations, a low glucose concentrations and b high glucose concentrations. The conversion of all conditions is 100%. Solid concentration in batch (g solids/L liquid) = solid:liquid ratio added to the reactor train (g added solids/L added liquid) in every countercurrent transfer. The liquid residence time in countercurrent saccharification is adjusted to reach the same batch reactor volume using the method in “Reactor volume calculation” section. The solid concentration in every stage in countercurrent saccharification is 250 g solids/L liquid. Enzyme-addition location is Stage 8. Operation time is 200 days. The substrate is α-cellulose. Batch simulations use the modified HCH-1 model. Countercurrent simulations use the CPDM model with the modified HCH-1 equation as the governing equation (Note: in this section, sampling was not included in the simulation of countercurrent saccharification)