颗粒接触特性对煅烧石油焦换热器传热性能的影响

Effect of Particle Contact Characteristics on Heat Transfer Performance of Calcined Petroleum Coke Heat Exchanger

为了探究煅烧石油焦颗粒间接触特性对换热器传热性能的影响,构建了换热器非稳态传热模型,研究了颗粒间接触(接触面积系数)变化对换热器传热性能的影响规律。结果表明:随着接触面积系数的增加,颗粒间接触越好,导热能力越强,颗粒层平均温度降低速率、蓄热量减少速率明显加快,固相平均传热贡献度、壁面综合传热系数和放热率增加,有效换热时间下降,当接触面积系数由0.03增加到0.07时,固相平均传热贡献度由83.4%上升到90.5%,壁面综合传热系数由12.7 W/(m^2 ·K)增加到27.1 W/(m^2 ·K),放热率从83.79%增加到98.2%,有效换热时间从8.02 h减小到5.07 h。

In order to investigate the influence of contact characteristics between particles of calcined petroleum coke on heat transfer performance of heat exchanger, a heat exchanger unsteady heat transfer model was established, and the influence law of the change of contact (contact area coefficient) between particles on heat transfer performance of heat exchanger was studied. The results show that with the increase of the contact area coefficient, the better the contact between particles, the stronger the thermal conductivity, the average temperature of granular layer reduction rate and the heat storage reduction rate are obviously accelerated. The average heat transfer contribution of solid phase, wall comprehensive heat transfer coefficient and heat release rate increase, and the effective heat transfer time decreases. When the contact area coefficient increased from 0.03 to 0.07, the average heat transfer contribution of solid phase increased from 83.4% to 90.5%. The wall heat transfer coefficient increased from 12.7 to 27.1 W/(m^2 ·K), the heat release rate increased from 83.79% to 98.2%, and the effective heat transfer time decreased from 8.02 to 5.07 h.