正辛烷在不同稀土含量Y型分子筛上吸附热力学的研究

发布时间：2018-03-25 18:34

本文选题：稀土含量　切入点：吸附热力学　出处：《石油炼制与化工》2017年03期

【摘要】：以正辛烷为吸附质,采用智能质量分析仪(IGA)和程序升温脱附(TPD)技术考察了不同稀土含量对Y型分子筛吸附热力学参数(吸附热、焓变、熵变)的影响及变化规律。结合TPD数据剖析了稀土含量调变分子筛催化活性的实质。结果表明:吸附质在分子筛上的吸附位作用力的大小与分子筛内稀土含量有关;较高含量稀土的引入,使得吸附质与分子筛的作用力加强,从而使吸附质在吸附剂上较难脱附,在分子筛上的停留时间较长,容易过度裂解,结焦生炭;而适量稀土的引入[w(Ce_2O_3)=4%],可以调变分子筛活性位上的吸附选择性,使得吸附质分子在吸附剂孔道内有序化呈现规律性,可以改变其在分子筛上的停留时间,进而有利于大分子裂解反应的发生,提高目标产物的收率。
[Abstract]:Using n-octane as adsorbent, the adsorption thermodynamic parameters (adsorption heat, enthalpy variation) of Y molecular sieve with different rare earth contents were investigated by means of intelligent mass analyzer (IGA) and temperature programmed desorption (TPD) technique. Combined with TPD data, the essence of the catalytic activity of molecular sieve modified by rare earth content was analyzed. The results showed that the adsorption force of adsorbent on molecular sieve was related to the content of rare earth in molecular sieve. With the introduction of rare earth, the force between adsorbate and molecular sieve is strengthened, so it is difficult to desorb adsorbent, and the residence time on molecular sieve is longer, so it is easy to over-cracking and coking. However, the introduction of rare earth elements [w _ ce _ 2O _ 3 + 4%] can adjust the adsorption selectivity on the active sites of molecular sieves, so that the adsorbate molecules in the adsorbent channels can be ordered regularly and their residence time on the molecular sieve can be changed. Thus, it is advantageous to the occurrence of macromolecular pyrolysis reaction and the improvement of the yield of the target product.
【作者单位】：辽宁石油化工大学辽宁省石油化工催化科学与技术重点实验室;中国石油大学(华东)化学工程学院;
【基金】：国家自然科学基金项目(21376114)
【分类号】：TE624.9;O647.3

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