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采用IGA-100型智能重力分析仪测定在100～300℃,0.01～10kPa下,5A分子筛对正己烷的吸附速率曲线,分析了不同二次孔分布的成型5A分子筛颗粒5A-1和5A-6对正己烷的吸附扩散性能.结果表明:5A-1与5A-6分子筛具有相近的微孔和中孔孔径分布;5A-6分子筛在孔径0.1～1μm范围内拥有相对更大的二次孔孔容,而在孔径小于0.01μm时拥有更丰富的二次孔分布;丰富的二次孔分布使得正己烷在5A-6分子筛上的有效扩散系数De为10-6～10-4cm2/s,是5A-1分子筛的2～5倍;随着吸附温度从100℃增大至300℃,5A-1分子筛上的有效扩散系数从5×10-7～2×10-6cm2/s增大至2×10-5cm2/s,而在5A-6分子筛上的有效扩散系数随着吸附温度变化不明显;吸附压力从0.01kPa升高至10kPa,引起正己烷分子平均自由程从627.15～963.28μm下降至0.63～0.96μm,并与分子筛二次孔孔径相当,引起Knudsen扩散加剧,从而使正己烷在5A分子筛上的有效扩散系数于压力1kPa前后呈现先上升后下降的变化趋势.
The adsorption rate curves of 5A molecular sieve to n-hexane at 100 ~ 300 ℃ and 0.01 ~ 10kPa were measured by IGA-100 intelligent gravimetric analyzer. The effects of different secondary pore distribution on the formation of 5A molecular sieve 5A-1 and 5A-6 The results showed that 5A-1 and 5A-6 zeolites had similar micropore and mesopore pore size distributions. 5A-6 zeolite possessed relatively larger secondary pores in the range of 0.1 ~ 1μm While the secondary pore distribution is more abundant when the pore diameter is less than 0.01 μm. The abundant secondary pore distribution makes the effective diffusion coefficient of n-hexane on 5A-6 molecular sieve 10-6 ~ 10-4cm2 / s, which is 5A-1 molecular sieve. With the increase of adsorption temperature from 100 ℃ to 300 ℃, the effective diffusion coefficient on 5A-1 molecular sieve increased from 5 × 10-7 ~ 2 × 10-6cm2 / s to 2 × 10-5cm2 / s, while the effective diffusion coefficient on 5A-6 molecular sieve did not change with the adsorption temperature. The adsorption pressure increased from 0.01kPa to 10kPa, and the average free path of n-hexane decreased from 627.15 to 963.28μm 0.63 ~ 0.96μm, and the molecular sieve secondary pore diameter equivalent, causing Knudsen proliferation increased, so that the effective expansion of n-hexane in the 5A molecular sieve 1kPa factor in pressure before and after the show a downward trend after an initial increase.