Study On The Key Technology And Distillation Equipment Of Fuel Ethanol Produced By Solid Fermentation Of Sweet Sorghum Stalk

Sustainable and clean renewable energy has attracted extensive attention worldwide as world energy consumption continuously increased.Sweet sorghum is a promising energy crop for biofuels production since it has no threaten to food,feed and industrial raw materials.Furthermore,it can be planted on marginal lands such as the saline and alkaline lands.Therefore,biofuels production using sweet sorghum has spreading social and environmental benefits.In the past several years,a cost competitive integrated technology of advanced solid-state fermentation(ASSF)for bioethanol production from sweet sorghum stalks was developed in our lab.In this thesis,the process parameters of solid-state fermentation were optimized systematically.A rapid analytic method for quantitative analysis of products from solid-state fermentation was developed.A high-titer sulfur dioxide tolerant strain was screened during preservation experiments of sweet sorghum stalks.The optimum operating conditions in batch solid-state distillation was investigated.The main work and conclusions were as follows:1.The operating conditions in solid-state fermentation was optimized.The optimum seed culture of S.cerevisiae TSH4 was 10%(v/v).The loading rate and rotation rate of fermenter showed insignificant effects on sugars utilization.S.cerevisiae TSH4 exhibited strong resistance to sulfur dioxide,which build a foundation for raw material storage in the industrial application of ASSF technology.2.A rapid quantitative analysis of sugars and ethanol from solid vinasse was developed.High-speed homogenizing for 2 minutes was able to release all the target components into liquid phase.The recovery of sucrose and ethanol at low,medium and high levels of spiking were ranged from 95%to 105%.The rapid quantitative analysis of solid fermented residues driven by solid-to-liquid extraction is of reliable,low cost,and high efficiency,thereby largely increasing the accuracy of process monitoring of solid-state fermentation at industrial scale.3.An adverse-flow tower was developed based on traditional rectification tower.The new designed adverse-flow tower solved the seal problems during distillation of solid fermented residues.The optimal steam flow was 4 kg/h.The vapor input was 4.28 ton per ton ethanol,which reduce the energy consumption by half comparing with traditional rectification tower.4.Large-scale solid-state fermentation and distillation system were verified.The sealability of new designed adverse-flow tower was also verified during large scale operation.Ethanol recovery using our new designed adverse-flow tower reached 98%.96.5%of sugars conversion rate and 95%of ethanol metabolic yield were achieved in 550 m3 rotary-drum fermentation system using the optimal condition.In summary,the research results above lay a foundation for the continuous production of ASSF sweet sorghum ethanol,which further promoted the industrialization process of ASSF sweet sorghum ethanol.