Direct Distillation To Extract Ligno-cellulosic Bio-Ethanol

Lignocellulose is the most abundant and the cheapest renewable resource on Earth. After hydrolysis, saccharification and fermentation, the biofuel ethanol can be produced by cellulose, which is obtained from lignocellulose after pretreatment and removal of xylogen. In this paper, ethanol was produced from corn stover fermentation liquid by direct distillation process in the steel tray-packing compound distillation column.The study was about the distillation process of corn stover fermentation slurry with high solid loading and high viscosity, the steel tray-packing compound distillation column was designed, direct distillation without filtration was applied to extract ethanol. The batch distillation experiment in glass packing column showed that ethanol yield from direct distillation was 8.14% higher than distillation after being centrifugated. The corn stover fermentation slurry with solid loading of 11.56wt% belongs to pseudoplastic fluid, power law module wasτ=500.85γ0101 with correlativity of 0.999. The relation from the viscosity of slurry and the rotational speed of impeller was established asμa=500.85(k·NY)-0.899, helical impeller showed a better effect than anchor impeller in direct distillation process.The distillation process was at the feed flow rate of 2.7 L/hr, in normal pressure, the influence on ligno-cellulosic bio-ethanol distillation from reflux ratio, rotational speed of impeller and the feed concentrate, temperature and feed tray location were researched. The results showed that for higher top ethanol purity and yield, feeding at room temperature was suitable; feeding from 27th tray was optimum when feed concentrate being 10.68v%; the reflux ratio was controlled in 5.0 when feed concentrate being 10.59v%; rotational speed of impeller was controlled in 31～36 rpm. Top ethanol yield reached above 99% by way of regulating distillation process parameters, the separation efficiency improved compared with traditional processes.Choose ethanol and water as key components, use ASPEN PLUS to make simulation calculation in the distillation process of fermentation slurry. Top ethanol purity and yield were good coordinate with simulation results, as a result of the influence of the other volatile components in fermentation slurry, there is a certain deviation between the experiment results of temperature profile of distillation column and simulation results.