铂锡重整催化剂体系下正庚烷转化规律的研究

摘要

以链烷烃中较难转化的正庚烷为模型化合物,考察碱金属K、稀土Ce和K、双稀土金属(Ce和Eu)对铂锡重整催化剂体系下正庚烷转化的影响.结果表明:与铂锡催化剂相比,添加0.045％、0.060％的K,使得催化剂载体强L酸量下降,有利于抑制裂解反应,510℃时的裂解产物收率下降约5百分点,同时异构烷烃选择性上升约7百分点;添加0.28％Ce和0.010％、0.030％的K,510℃时的裂解产物选择性下降4.2～7.1百分点,异构烷烃选择性上升7.4～9.8百分点,但随着反应温度升高则对正庚烷转化的影响有一定程度的削弱;添加双稀土金属后,在较低反应温度(510℃)下能够有效降低裂解产物选择性、提升异构烷烃选择性,随着反应温度升高,双稀土对正庚烷转化的影响显著削弱.%n-Heptane,the paraffin that is difficult to convert,was used as a model compound to investigate the effect of potassium,mixture of rare earth cerium and potassium,and bi-rare earth metals (Ce,Eu)on n-heptane conversion.The results showed that adding potassium(0.045％,0.060％)decreases the strong Lewis acidity of catalyst support,inhibiting the cracking reaction.At 510 ℃,cracking products decrease about 5 percentage points and the selectivity of iso-paraffins increases about 7 percentage points;adding mixture of cerium (0.28％) and potassium (0.010％,0.030％) decreases the selectivity for cracking by 4.2-7.1 percentage points,while the iso-paraffin selectivity rises 7.4-9.8 percentage points at 510 ℃.Increasing reaction temperature has a weakened effect to certain extent on n-heptane conversion;Addition of bi-rare earth metals can effectively reduce the selectivity for cracking product at low temperature(5 10 ℃),but the iso-parafin selectivety rises.The effect of addition of bi-rare metals on heptane transformation is weakened significantly with increasing the reaction temperature.