Performance Study On A New Type Evaporator With Multi-Separation Chamber And Double Tube Pass Heater

Evaporation is an important link of chemical ,pharmacy ,metallurgical and water treatment industries and high-energy consumption unit operation in industry. So developing new type evaporator and enhancing heat transfer coefficient is one of energy saving effective measures.For the evaporation material that viscosity changes greatly with the concentration, low heat transfer coefficient is a high prevalence of problem in evaporation industry. In response to this problem, Professor Zhang Shaofeng of Hebei University of technology presented a new type evaporator with multi-separation chamber and double tube pass heater. For the sake of ease in research the operation and heat transfer characteristics, the whole separation chamber is divided into two tandem sub-chambers and each sub-chamber has double tube pass heater, take this as basic point a new type evaporator hot experimental platform of double separation chamber and double tube pass heater was established.With different compositions Glycerin and water solution being taken as materials, the performance of the new type evaporator was experimentally studied on a wide viscosity range. The effects of heat flux and viscosity on heat transfer coefficient of this new type evaporator were investigated and the result was compared with tradition natural circulation evaporator. The results show that:the new type evaporator performs stable on a wide viscosity range;The average heat transfer coefficient increases with heat flux rise and decreased with material viscosity; The heat transfer coefficient of sub-chamber increases with the first and the fourth heating pipe's heat flux rise; the difference of the heat transfer coefficient increases with the heat flux rise; Under the same heat flux conditions, The average heat transfer coefficient ordinal improve in order by single separation chamber and tube evaporator, double separation chamber and single tube pass evaporator and double separation chamber and double tube pass evaporator. In the range of this experiment, compared with single separation chamber and tube evaporator, the double-separation chamber and double tube pass evaporator could promote average heat transfer coefficient by 15%~20%. Through the regressive analysis of experimental data,correlation of the average heat transfer coefficient of double separation chamber and double tube pass evaporator was obtained, The average relative error of calculation is lower than 18%. In these experimental conditions, the relationship between solution concentration and evaporation time has been discussed. The results showed evaporation under double separation chamber condition could shorten the evaporation time and improve production efficiency.