【摘要】 针对煅烧石油焦与换热器的一次换热过程,构建了菱面体堆积条件下的非稳态传热模型,系统研究了粒径变化对一次换热过程的影响规律。研究结果表明:随着换热时间的增加,颗粒堆的温度和比焓均呈现先快后慢的下降趋势。随着粒径的增加,壁面综合换热系数和放热率增加,有效换热时间减小。当粒径由1.77 mm增至14.6 mm,壁面综合换热系数由1.81 W/(m~2·K)增至16.41 W/(m~2·K),放热率从39.58%增至85.24%,有效换热时间从1 282 min降至218 min。更多还原

【Abstract】 In order to study the primary heat transfer process between calcined petroleum coke and heat exchanger, an unsteady heat transfer model of rhombohedral stacking conditions was constructed to study systematically the influence of particle size change on the heat transfer process.It is showed that the temperature drop and the enthalpy drop of the particle layer with different particle sizes undergoes a trend of fast-slow.As the particle size increases, the integrated heat transfer coefficient and heat release rate of the particle heap is increased, and the effective heat exchange time of the particle heap is decreased.As the particle size increases from 1.77 mm to 14.6 mm, the wall heat transfer coefficient increased from 1.81 W/(m~2·K) to 16.41 W/(m~2·K), the heat release rate increased from 39.58 % to 85.24 %, and the effective heat exchange time decreased from 1 282 min to 218 min.更多还原