Research on the energy-saving efficiency of the two-effects system with vapor feed to reboiler*

As the forward-feed,backward-feed,dual-feed two-effect distillation are not better used at the conditions of the feed temperature being higher than the bubble point temperature,we chose new type distillation flow-two-effects system with vapor feed to reboiler.The effects of the feed composition and the feed temperature on the energy-saving efficiency of the two-effects system with vapor feed to reboiler are researched in ethanol-water system by process simulation.The following results showed that when the component of ethanol is less than 0.4,the vapor-feed B flow is the best and its energy-saving efficiency is more than 36%;at the component of ethanol more than 0.4,the vapor-feed a flow is the best and its energy-saving efficiency is more than 20%.When the temperature of the feed nearly the dew point temperature or more than 200℃,the energy-saving efficiency of the three vapor-feed flow is better.