自然循环自动清洗式高效节能蒸发器的核心理论研究

The Key Theory on the High Efficient and Energy Saving Evaporator of Self-Cleaning Type of Natural Circulation

严重影响现有蒸发器效益的焦点是高能耗的强制循环泵和加热面盐垢的周期性停车清洗。自然循环自动清洗式蒸发器能够满意地解决这两个问题 ,为企业创造相当可观的效益。以动力温度概念和不平衡汽化过程机理为基础的自然循环推动力理论研究 ,不仅得到有很大意义的计算模型 ,并且给出了自然循环推动力有效强化的思路 :设计较大截面、足够深度、出口部呈渐扩形的沸腾室来提高汽化的平衡度、降低出口动能损失 ;必须采用安装有像螺旋齿带那样能够低流速下自转、高效强化传热、较低流体阻力的自动清洗元件的短管加热室 ,以便增大动力温度 ,又使自然循环总阻力较低。按此动力学理论设计的自然循环自动清洗式蒸发器顺利地获得中试成功。

The main factors that have severe effect on evaporators are the forced circulation pump of high energy consumption and the cyclical stop of equipment operation to remove the salt fouling. The self-cleaning evaporator of natural circulation is able to solve such problems satisfactorily and help make great profits in industry. The theoretical research of the driving force of natural circulation is based on the concept of dynamic temperature and the process mechanism of disequilibrium vaporization. Not only the significant calculating model is made, but also the method is deduced, to effectively enlarge the driving force of natural circulation. The boiling chamber of large cross-section, enough depth and gradually increased section at outlet is designed in order to increase the vaporization equilibrium and reduce the kinetic energy loss at outlet. The heat transfer tubes in the heating chamber must be short, in which twisted strip with oblique teeth are installed whose function is to efficiently remove salt fouling automatically and enhance heat transfer with low flow resistance at low fluid flowing velocity, so that the dynamic temperature is raised and the overall resistance of natural circulation is low. The industry experiments of such new evaporators have been successful, which are designed according to this theory.