Improving Ethanol Production through Continuous Fermentation
We investigate various models for the production of ethanol through continuous fermentation. Using continuous fermentation, rather than other methods such as centrifuges and settling tanks, the productivity has been shown to increase by up to four fold. The models, which have been verified experimentally, possess a rich array of complex dynamic behaviours. These include periodic and period doubling solutions. In certain parameter regions, the latter solutions have been shown to be a path to chaotic behaviour in the reactor.
Numerous studies have investigated these models using direct integration. This approach is time consuming as parameter regions of interest can only be determined through laborious and repetitive calculations. More importantly, crucial regions of parameter space (in terms of optimal performance) can easily be missed by using this approach. We show how techniques from nonlinear dynamical systems theory, in particular a combination of steady-state analysis and path following methods, can be used to gain practical insights into this operating strategy. We extend the analysis to investigate the possibility of improving the production of ethanol through continuous fermentation by using a network of two reactors arranged in series. Performance of such a cascade configuration will be compared with
those obtained from a single tank.