物理化学学报Issue(2)：358-364,7.DOI:10.3866/PKU.WHXB201211143
稀释蒸汽中Na及积炭对甲醇制丙烯催化剂性能影响
Effects of Na+ in Dilution Steam and Coke Deposition on Catalytic Performance of Methanol-to-Propylene Catalysts
摘要
Abstract
The effects of Na+ in dilution steam and coke deposition on the physicochemical properties and catalytic performance of ZSM-5 catalysts for the methanol-to-propylene (MTP) reaction were investigated. The deactivated and regenerated catalysts were characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray fluorescence (XRF) spectrum, nitrogen adsorption/desorption, temperature-programmed desorption of ammonia (NH3-TPD), and thermogravimetry (TG). Their catalytic performance for MTP reaction was tested in a continuous flow fixed-bed micro-reactor at 470 °C, 101325 Pa, and with methanol weight hourly space velocity (WHSV) in the range of 1.0-3.0 h-1. The results indicated that the catalyst crystal structure and morphology was not significantly altered after 970 h on stream. In the MTP reaction, Na + in the dilution steam can easily enter the pore channels of the catalyst, and partial y replace H protons, thereby gradual y decreasing the amount of acidity and acid strength of the catalyst, which eventual y causes deactivation. In addition, coke deposits on the catalyst surface blocking its micropores are the main reason for deactivation of the MTP catalyst. Coke deposits are mostly eliminated through the burning charcoal regeneration process. The effect of framework dealumination from the catalyst by steam in the MTP process is slow but more serious. Through regeneration and ion exchange process, the catalytic activity of the deactivated catalyst can be ful y restored. The conversion of methanol is consistently above 99%, and propylene selectivity is greater than 46% even after 470 h on stream. With increasing reaction time, the propylene selectivity gradual y increases, while ethylene selectivity gradual y decreases.关键词
甲醇制丙烯催化剂/积炭/再生/稀释蒸汽Key words
Methanol-to-propylene catalyst/Coke deposition/Regeneration/Dilution steam分类
化学化工引用本文复制引用
王峰,顔蜀雋,雍晓静,罗春桃,张卿,温鹏宇,巩雁军,窦涛..稀释蒸汽中Na及积炭对甲醇制丙烯催化剂性能影响[J].物理化学学报,2013,(2):358-364,7.基金项目
The project was supported by the International S&T Coopperation Program of China (2010DFB40440) and S&T Programs of Ningxia, China (Industrial Operation and Key Technology Research for 500000 t/a Coal-Based Polypropylene Plant).@@@@国际科技与交流专项(2010DFB40440),宁夏回族自治区科技攻关计划(年产50万吨煤基聚丙烯装置工业运行及下游产业关键技术研究)资助项目 （2010DFB40440）
