摘要
采用稳态吸附方法，测定了示踪剂在下行式流化床反应器中的轴向浓度分布，并与理论分布进行拟合，利用Ｍａｒｑｕａｒｄｔ法，求取了不同操作条件下的轴向扩散系数与气固传质系数，藉以揭示并流下行循环流化床反应器中的气固传质特性．基于实验结果，通过因次分析与线性回归，得到了轴向扩散系数Ｅａ及传质系数ＫＦａ与操作条件的经验关联式：Ｐｅ１≡（Ｌｕｆ）／Ｅａ＝０．２２６Ｒｅ０．４９９ＰΘ－０．３０２Ｐｅ２≡ｕｆ／（ＫＦａ．Ｌ）＝０．０００１８５Ｒｅ０．６１８ｐΘ－０．９８３Θ≡Ｇｓ／（ｕｆρｐ）＝ｕｓ（１－ε）／（ｕｇε）关联式与实验数据拟合较好．
The characteristics of gas-solid mass transfer in the title reactor are investigated in the present work. Experiments were conducted to measure the axial tracer concentration distribution under various operating conditions by using the steady-state adsorption method. Mass transfer coefficient and axial diffusion coefficient were obtained by means of a non-linear retrieval method (the Marquardt method). It is found that the operating parameters influence the mass transfer coefficient in a complicated way, and the effect of apparent gas velocity is more remarkable than that of solid circulating rate. The empirical correlation of experimental data for axial diffusion coefficient E a and overall mass transfer coefficient K F a were obtained as follows:Pe 1≡Lu f /E a =0.226Re 0.499 pΘ -0.302 Pe 2≡u f/(K F αL)=0.000185Re 0.618 pΘ -0.983 with Θ ≡G s /(u f ρ p )=u s (1-ε)/(u g ε).They fit the experimental data very well (relative error below 7% and 9% respectively).
出处
《化工冶金》
CSCD
北大核心
1997年第3期221-228,共8页
关键词
并流下行
循环流化床
气固传质
Downflow, Circulating fluidized bed,Gas-solid mass transfer
