气-液-固三相逆流化床热量传递研究

在内径0.152 m,高2.5 m的气-液-固三相逆流化床中系统研究了热量传递特性特性。获得了气体和液体速度及聚乙烯和聚丙烯颗粒密度对内置加热器与床层间热量传递系数的影响规律。研究结果表明密度相对高的聚乙烯颗粒的逆流化床的热量传递系数比密度相对低的聚丙烯颗粒的逆流化床的热量传递系数大;随着气体速度的增加,热量传递系数增加。然而,随着液体速度增加,热量传递系数具有最大值。在热量传递系数达到最大值时对应的液体速度随着颗粒密度或气体速度的增加而降低。

Study on Heat Transfer in Gas-Liquid-Solid Three Phases Inverse Fluidized Bed

A gas-liquid-solid three phases inverse fluidized bed with 0.152 m diameter and 2.5 m height was employed to investigate the characteristics of heat transfer. Effect of gas and liquid velocities and particle density (polyethylene and polypropylene) on the immersed heater-to-bed heat-transfer coefficient was determined. The results show that the heat-transfer coefficient in two- and three-phase inverse fluidized beds with relatively high density particles (polyethylene) is higher than that in the beds with relatively low density particles (polypropylene). The heat-transfer coefficient increases with increasing of gas velocity. However, it exhibits the maximum value with increasing of liquid velocity in liquid-solid as well as three- phase inverse fluidized beds. The liquid velocity decreases with increasing of particle density or gas velocity when the heat-transfer coefficient reaches to the maximum value.