摘要
为获得较高的对二甲苯选择性,采用脉冲实验对BaX分子筛进行评价,系统研究了分子筛骨架硅铝比、钠离子交换度和含水率对分离系数的影响规律。结果表明:分子筛骨架硅铝比从2.01增加至2.53时,对二甲苯相对于间二甲苯、邻二甲苯的分离系数(βP/M、βP/O)均先增大后减小,骨架硅铝比为2.2~2.4时二者达到最高点;对二甲苯相对于乙苯的分离系数(βP/E)呈线性减小趋势;随着钠离子交换度的提高,βP/E,βP/M,βP/O增大,钠离子交换度大于94.3%时三者达到最大值;BaX分子筛的含水率(ω)从2.0%增加至8.2%时,βP/E,βP/M,βP/O均先增大后减小,含水率(ω)为4.0%~5.0%时选择性最佳;在二元混合体系下通过静态吸附平衡测定对二甲苯相对于对二乙苯的分离系数(βPX/PDEB),较高骨架硅铝比BaX分子筛的屏βPX/PDEB。随对二甲苯质量分数的变化较小,且更接近于1.0。
The para-xylene adsorption performance of BaX zeolite was evaluated by pulse adsorptionseparation method to study the influences of SIO2/Al2O3 molar ratio of X zeolite, Na+ exchange ratio and water content on the PX selectivity of the zeolite. It is found that with increasing the SIO2/Al2O3 molar ratio from 2.01 to 2.53, the separation factors of PX relative to meta-xylene (βP/M) and ortho-xylene (,8 ejo) increase first, and then decrease, reach the highest point at SIO2/Al2O3 molar ratio of 2.2--2.4; while in this range, the separation factor of PX relative to ethylbenzene (βP/E) exhibits a linear decrease. All of ,βP/M, βP/O and ,βP/E increase with the increase of Na^+ exchange ratio, and are up to the peak value when Na+ exchange ratio is higher than 94.3 %. As the water content in the BaX zeolite increases from 2.0V0 to 8.2%, the separation factors of ,βP/M, βP/O and ,βP/E rise first and then decrease, and achieve the highest points at the water content of 4. 0 %-5.0%. The separation factors of PX relative to para-diethyl benzene (,SPX/PDEB) in PX-PDEB binary mixture studied by static adsorption equilibrium experiment show that the ,SPX/PDEB changes slightly at higher SiO2/Al2O3 molar ratio as the PX content varies, the value of which is very close to 1.0.
出处
《石油炼制与化工》
CAS
CSCD
北大核心
2016年第3期1-4,共4页
Petroleum Processing and Petrochemicals
关键词
吸附分离
选择性
芳烃
对二甲苯
adsorptive separation
selectivity
aromatics
para-xylene