恒再沸比提馏式间歇精馏的最小再沸流比与能耗分析

Energy consumption analysis and minimum reboil ratio in batch stripping distillation at constant reboil ratio

通过构造一函数,推导出二元恒再沸比提馏式间歇精馏,在理想操作条件下,理论板数趋向无穷多时,瞬时恒浓区变化方式可由此函数值(>0或<0)来判断,完善了二元恒再沸比提馏式间歇精馏最小再沸比计算方法。推导出二元恒残液组成提馏式间歇精馏,在理想操作条件下的最小汽化总量的计算公式。通过对理论板数趋向无穷多时的能耗分析得到,二元提馏式间歇精馏,要求残液中重组分的收率和平均浓度均高时,相对于恒残液组成操作,采用恒再沸比操作能耗较高,其主要原因是低效总能耗(理论板数趋向无穷多时,直接表现为无效总能耗)在总能耗中占比例较大。

For a batch binary stripping distillation under ideal operating condition,with constant reboil ratio and infinite number of theoretical plates,a function was derived in this study,and the variation of instantaneous constant composition region may be evaluated by the value of this function.Thus the calculation method for the minimum reboil ratio of the batch binary stripping distillation was improved.A formula was deduced for computing the minimum total vapor capacity of the distillation under constant residual fraction composition and ideal operating condition.The results show that to achieve high yield and high average concentration of heavy component in the residual fraction,the energy consumption of the batch stripping distillation at constant reboil ratio is higher than that at constant residual fraction composition because the low efficient consumption of total energy（which is the inefficient total energy consumption with infinite number of theoretical plates）accounts for a large portion of the total energy consumption.