氧热法电石生产复合床反应器预热区的设计计算

针对氧热法电石生产工艺中复合床反应器预热区高温CO和原料层进行热交换的体系，建立了计及原料颗粒内热阻的移动床气固两相换热模型。重点考察了反应器预热区气固两相温度的分布，计算了不同原料粒径和不同预热区直径条件下，达到反应器换热要求所需要的换热高度，并得到了气固两相温度分布的解析解。结果表明：（1）颗粒粒径较大时（ε的值小于33），颗粒内热阻成为气固两相换热过程的控制步骤，综合考虑床层透气性和床层压降等制约条件，在可选范围之内应优先选用直径为1cm的原料；（2）移动床气固换热过程主要受控于ε、β和γ这3个无因次参量，并且主要受控于ε；（3）气固两相温度分布的解析解，能为此类颗粒移动床换热过程提供初步设计依据。

Design of the preheated area in a combined bed reactor for oxygen heating production of calcium carbide

A moving bed reactor model was set up for the heat exchange between CO and solid particles in the preheated area of a combined bed reactor for oxygen heating calcium carbide production; the model takes into consideration the resistance to heat transfer by conduction in the particles. Temperature distributions in the gas and solid phases were calculated analytically and numerically, and the heights required for heat balance between particles and gas were obtained for the preheated area and particles of different diameters. It is demonstrated that: (1) For larger particles, conduction in the particles becomes the limiting step in gas- solid heat transfer, and based on a comprehensive consideration of the bed permeability and bed pressure drop, a particle diameter of 1cm is the optimum choice for the combined bed reactor; (2) The heat exchange in moving beds is controlled by ε, β and γ, and ε is the main factor; (3) The analytical solution of temperature distribution can be used as the basis for the design of moving-bed heat exchangers.