回转窑用集热器的设计需求及结构优化

Design Requirements and Structure Optimization of Heat Recovery Exchangers on Rotary Kilns

减少回转窑表面的散热损失对水泥工业的节能具有重要意义。针对现有的窑表面集热器回收效率低、加工制造较为复杂的现状,提出了一种新型的六边形管束集热器,并通过理论分析和实验手段确定了其所需换热量。在此基础上,建立了集热器设计需求与管长、管数以及管径等结构参数之间的数学关系,利用遗传算法对集热器的结构进行优化设计。结果表明:优化后的集热器所需换热面积相比实际值减少30%。在相同换热量的情况下,压降的变化对优化设计的换热面积结果影响不大,而对结构参数的选取影响较大。

To reduce heat loss from the shell of a rotary kiln is of great significant for saving energy consumption in cement industry.In this paper,a novel heat recovery exchanger installed on the shell surface is proposed to preheat water.The heat recovery exchanger contains hexagonal water tubes which are easily manufactured and is favorable for saving the cost.A mathematic model is analyzed to determine the shell temperature and heat loss rate along the rotary kilns.Theoretical analyses and experimental measurements are carried out to investigate the temperature and heat transfer rate of heat recovery exchanger,i.e.the design requirements of the heat exchanger.Based on these analyses,an optimization model is put forward to describe the relation between the design requirements and structural parameters of the heat recovery exchanger,i.e.the tube length,the tube numbers and the tube diameter.With the aid of genetic algorithm toolbox in Matlab,the optimized design parameters are obtained.The results show that the optimized heat transfer area is decreased by 30%compare with the value before optimization.What＇s more,in the cases of different pressure drop,the design parameters of the heat recovery exchanger change while the required heat transfer area remains the same.