正戊烷和正己烷在无黏结剂5A分子筛上的吸附动力学特性

测定了正戊烷和正己烷在无黏结剂和有黏结剂5A 分子筛上的吸附动力学,采用简化的扩散动力学模型计算了扩散系数,并估算了扩散活化能。实验结果表明,正构烷烃在无黏结剂和有黏结剂5A 分子筛颗粒上的吸附分别受微孔扩散控制和大孔扩散控制。黏结剂的存在降低了正构烷烃的扩散速率。在300～480 K,正戊烷和正己烷在无黏结剂5A 分子筛上的微孔扩散系数分别为(4.71～11.34)×10~(-12),(1.23～5.19)×10~(-12)cm~2/s;在有黏结剂5A 分子筛上的大孔扩散系数分别为(6.68～26.35)×10~(-6),(2.40～11.51)×10~(-6)cm~2/s。正戊烷和正己烷在无黏结剂5A 分子筛上的扩散活化能分别为7.87,10.15 kJ/mol;在有黏结剂分子筛上的扩散活化能分别为9.02,10.92 KJ/mol。

Adsorption Kinetics of n-Pentane and n-Hexane on Binder-Free 5A Molecular Sieve

Adsorption kinetics of n-pentane and n-hexane on 5A molecular sieve with/without binder were studied.Diffusivities were derived from simplified model and diffusion activation energies were evaluated.Adsorption rate of n-paraffins on 5A molecular sieve pellets without binder is controlled by micropore diffusion while on 5A molecular sieve pellets with binder is controlled by macropore diffusion.In temperatures range of 300-480 K,diffusivities of n-pentane and n-hexane on binder-free pellets are(4.71-11.34)10~(-12) and(1.23-5.19)10~(-12) cm~2/s,respectively. Diffusivities of n-pentane and n-hexane on the pellets with binder are(6.68-26.35)10~(-6) and (2.40-11.51)10~(-6) cm~2/s respectively.The diffusion activation energies of n-pentane and n-hexane are 7.87 and 10.15 kJ/mol for binder-free 5A molecular sieve respectively,and 9.02 and 10.92 kJ/mol for 5A molecular sieve with binder respectively.