Na含量对USY分子筛酸性和焦炭选择性的影响研究

采用FTIR、MAT、XRD考察不同Na含量USY分子筛的酸性、水热稳定性。结果表明,在一定晶胞和稀土含量下,随着Na含量的增加,分子筛的稳定性和活性降低,B酸、L酸都降低。通过强酸量、弱酸量的变化趋势可以看出,采用浸渍方法浸渍上去的Na优先作用于分子筛的强酸部分,尤其是分子筛骨架上的强酸部位。MAT反应结果表明,USY分子筛的积碳含量随分子筛Na含量的增加而降低,且焦炭选择性随Na含量的增加呈增加趋势。

Study on the effect of Na content on acidity and coke selective of USY

The techniques such as FTIR,MAT,XRD were used to investigate acid properties and hydrothermal stability of USY zeolite with different Na content.The results showed that under the certain crystal cell and rare earth content with the increase of Na content,the stability and activity of USY deceased as well as the B acid and L acid.The change trend of the amount of strong acid and weak acid indicated that Na＋ dipped in USY preferentially acts with the strong acid of molecular sieves,especially with that of the molecular sieve skeleton.The testing results of MAT indicated that the coke yield decreased while coke selectivity increased with the increase of Na content.