基于镓改性ZSM-5分子筛作用下的环氧树脂催化热解制芳烃反应性能研究

Reaction Performance of Epoxy Resin Based on Ga-Modified ZSM-5 Zeolite for Catalytic Pyrolysis to Aromatics

为实现环氧树脂的清洁处置与资源化利用,在一系列金属镓改性的ZSM-5催化体系中进行快速热解实验,并进行了包括氮气吸附-脱附测试、X射线衍射(XRD)、氨气程序升温吸附(NH3-TPD)、热重分析(TGA)和透射电镜(TEM)在内的全面的催化剂表征,以阐明催化剂的结构特性。镓的改性显著调节了ZSM-5分子筛的布朗斯特/路易斯酸分布和孔隙结构,改善了高温下分子筛的热解脱氧性能,提高了催化剂的择形催化能力。选取镓负载量、热解温度、催化剂用量、热解升温速率和催化剂回用次数为实验变量,探究了热解油组成分布的变化规律。结果表明,与未改性的分子筛相比,镓改性的ZSM-5分子筛显著提高了环氧树脂快速热解过程中芳烃的选择性。通过不同热解条件的研究发现,环氧树脂催化热解制备芳烃的最佳条件为:1Ga-ZSM-5分子筛∶环氧树脂=1∶1,热解温度为600℃,热解速率为10℃/ms,此时芳烃总选择性最高可达56.4%,其中更有价值的单环芳烃的相对含量达到31.6%。

To realize the clean disposal and resource utilization of epoxy resin,rapid pyrolysis experiments were carried out under a series of metallic Ga-modified ZSM-5 catalytic systems.A comprehensive catalyst characterization including N2adsorption-desorption,X-ray powder diffraction(XRD),NH3temperature-programmed desorption(NH3-TPD),thermogravimetric analysis(TGA)and transmission electron microscope(TEM)were performed to elucidate the structural properties of the catalysts.The modification of gallium significantly modulated the Bronsted/Lewis acid distribution and pore structure of ZSM-5 zeolite,improved the pyrolytic deoxygenation performance of the zeolite at high temperature,and enhanced the shape-selective catalytic ability of the catalyst.Gallium loading,pyrolysis temperature,catalyst dosage,pyrolysis temperature rise rate and catalyst recycle times were selected as experimental variables to investigate the changing pattern of pyrolysis oil composition distribution.The results showed that the Ga-modified ZSM-5 zeolite significantly improved the selectivity of aromatics during the rapid pyrolysis of epoxy resin compared with the unmodified zeolite.Through the study of different pyrolysis conditions,it was found that the best conditions for the preparation of aromatics by epoxy resin catalytic pyrolysis were 1Ga-ZSM-5 zeolite:epoxy resin=1:1,the pyrolysis temperature was 600℃,and the pyrolysis rate was 10℃/ms,when the total aromatic selectivity was up to 56.4%,and the relative content of the more valuable monocyclic aromatic hydrocarbons reached 31.6%.