在VHG条件下测试了甘蔗糖蜜的发酵能力,糖密发酵可在10.1—17.6％(W/V)可溶固形物范围内进行,当可溶固形物浓度增加时,糖实际转化为就酒精的百分比就下降,在VHG发酵中糖蜜作为一种碳源添加剂的可行性也得以研讨,糖蜜可分别用于提高麦芽...在VHG条件下测试了甘蔗糖蜜的发酵能力,糖密发酵可在10.1—17.6％(W/V)可溶固形物范围内进行,当可溶固形物浓度增加时,糖实际转化为就酒精的百分比就下降,在VHG发酵中糖蜜作为一种碳源添加剂的可行性也得以研讨,糖蜜可分别用于提高麦芽汁和甘蔗汁中的可溶固形物含量使其达到VHG(Vey High Gravity)水平,在VHG发酵中用糖蜜作添加剂的麦芽汁,其中90—93％对发酵有作用,酵母浸膏能提高发酵率,但对最终的酒精浓度影响较小,由于酵母浸膏或尿素不促进甘蔗/糖蜜的发酵率或提高最终酒精浓度,因此推论甘蔗汁并不缺乏可同化的氮源,这是第一篇关于以与小麦,麦芽汁和葡萄汁等不相同的原料进行VHG发酵技术利用的报道,该文指出了糖类的VHG发酵技术与目前工业生产技术相比能稳定提高酒精浓度。展开更多
Fuel ethanol is an important renewable and sustainable fuel, produced in China by fermentation of mostly corn, wheat and cassava feedstock. Fermentation produces an ethanol-lean broth (10 to 12 vol%). Ethanol is recov...Fuel ethanol is an important renewable and sustainable fuel, produced in China by fermentation of mostly corn, wheat and cassava feedstock. Fermentation produces an ethanol-lean broth (10 to 12 vol%). Ethanol is recovered by distillation, followed by a molecular sieve drying beyond the azeo-tropic point. The distillation and molecular sieve operations consume most of the total energy used, with the steam consumption currently being ~1.8 kg/kg ethanol, including 0.5 kg/kg ethanol in the final molecular sieve stage during regeneration. The objectives of the paper are fourfold: 1) firstly to study the distillation process of a large-scale cassava-based fuel ethanol production (200,000 tons per year), by field measurements and by using an Aspen Plus V8.2 simulation, with and without energy integration of condensers and reboilers, resulting in a distillation steam consumption of ~1.3 kg/kg ethanol;2) secondly, to examine the effects of using Very High Gravity (VHG) fer-mentation of cassava meal mash. By using VHG fermentation, the ethanol concentration in the fermenter broth is significantly increased, to about 19 vol% (15.4 wt%). The steam consumption is then reduced to ~0.94 kg/kg, representing a considerable saving in comparison with the current operation. Applying VHG fermentation needs minor additional investment, rapidly recovered through the energy savings and the smaller size of equipment;3) thirdly, to assess the application of a hybrid operation, where pervaporation will be used to selectively and continuously remove ethanol from the fermenter broth, thus slightly increasing the fermentation yield by reducing the risk of ethanol inhibition, whilst producing an ehtanol-rich permeate (about 30 wt%);and finally 4) to demonstrate that the production cost of cassava-based ethanol can substantially be reduced by applying the proposed improvements.展开更多
文摘在VHG条件下测试了甘蔗糖蜜的发酵能力,糖密发酵可在10.1—17.6％(W/V)可溶固形物范围内进行,当可溶固形物浓度增加时,糖实际转化为就酒精的百分比就下降,在VHG发酵中糖蜜作为一种碳源添加剂的可行性也得以研讨,糖蜜可分别用于提高麦芽汁和甘蔗汁中的可溶固形物含量使其达到VHG(Vey High Gravity)水平,在VHG发酵中用糖蜜作添加剂的麦芽汁,其中90—93％对发酵有作用,酵母浸膏能提高发酵率,但对最终的酒精浓度影响较小,由于酵母浸膏或尿素不促进甘蔗/糖蜜的发酵率或提高最终酒精浓度,因此推论甘蔗汁并不缺乏可同化的氮源,这是第一篇关于以与小麦,麦芽汁和葡萄汁等不相同的原料进行VHG发酵技术利用的报道,该文指出了糖类的VHG发酵技术与目前工业生产技术相比能稳定提高酒精浓度。
基金Supported by the National Key Sci&Tech Project of the 11th 5-year Plan of China(No.2007BAD78B04)the Provincial Key Sci&Tech Project of Sichuan,China(No.027.X028-037)
文摘Fuel ethanol is an important renewable and sustainable fuel, produced in China by fermentation of mostly corn, wheat and cassava feedstock. Fermentation produces an ethanol-lean broth (10 to 12 vol%). Ethanol is recovered by distillation, followed by a molecular sieve drying beyond the azeo-tropic point. The distillation and molecular sieve operations consume most of the total energy used, with the steam consumption currently being ~1.8 kg/kg ethanol, including 0.5 kg/kg ethanol in the final molecular sieve stage during regeneration. The objectives of the paper are fourfold: 1) firstly to study the distillation process of a large-scale cassava-based fuel ethanol production (200,000 tons per year), by field measurements and by using an Aspen Plus V8.2 simulation, with and without energy integration of condensers and reboilers, resulting in a distillation steam consumption of ~1.3 kg/kg ethanol;2) secondly, to examine the effects of using Very High Gravity (VHG) fer-mentation of cassava meal mash. By using VHG fermentation, the ethanol concentration in the fermenter broth is significantly increased, to about 19 vol% (15.4 wt%). The steam consumption is then reduced to ~0.94 kg/kg, representing a considerable saving in comparison with the current operation. Applying VHG fermentation needs minor additional investment, rapidly recovered through the energy savings and the smaller size of equipment;3) thirdly, to assess the application of a hybrid operation, where pervaporation will be used to selectively and continuously remove ethanol from the fermenter broth, thus slightly increasing the fermentation yield by reducing the risk of ethanol inhibition, whilst producing an ehtanol-rich permeate (about 30 wt%);and finally 4) to demonstrate that the production cost of cassava-based ethanol can substantially be reduced by applying the proposed improvements.
