Study on the deactivation and regeneration of the ZSM-5 catalyst used in methanol to olefins
Study on the deactivation and regeneration of the ZSM-5 catalyst used in methanol to olefins
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DOI：
10.1016/s1003-9953(10)60183-1
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发表时间：
2011-05-01
影响因子：
--
通讯作者：
Cao, Weiliang
中科院分区：
文献类型：
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作者：
Zhang, Jingchang;Zhang, Haibin;Cao, Weiliang
经微量金属阳离子改性的ZSM-5分子筛催化剂对甲醇制烯烃（MTO）反应具有高活性和高选择性，但在反应过程中容易失活。本文通过x射线衍射（XRD）、N(2)吸附-解吸、红外光谱（IR）以及红外光谱与NH(3)分子探针（IR-NH(3)）耦合研究催化剂失活机理和再生方法。这些表征表明，结焦是催化剂失活的主要原因。为了使失活催化剂再生，采用了煅烧和甲醇浸出两种方法。N(2)吸附-解吸、IR和IR- nh3表征表明，两种方法均能消除催化剂上沉积的焦炭，使催化剂再活化。XRD分析表明，再生后催化剂的结构没有发生变化。有趣的是，再生催化剂对MTO反应的催化性能甚至优于新鲜催化剂。此外，煅烧再生法可以更彻底地消除焦炭，而甲醇浸出法更容易在反应器中就地进行。
ZSM-5 zeolite catalyst modified by a trace of metal cations shows high activity and high selectivity for the reaction of methanol to olefins (MTO), but it inclines to deactivate during the reaction. In this paper, the mechanism of the catalyst deactivation and the regeneration method were studied by X-ray diffraction (XRD), N(2) adsorption-desorption, infrared spectra (IR), and infrared spectra coupled with NH(3) molecular probes (IR-NH(3)). These characterizations indicated that coke formation was the main reason for the catalyst deactivation. To regenerate the deactivated catalyst, two methods, i.e., calcination and methanol leaching, were used. N(2) adsorption-desorption, IR and IR-NH(3) characterizations showed that both methods can eliminate coke deposited on the catalyst and make the catalyst reactivated. XRD showed that the structure of the catalyst did not change after regeneration. Interestingly, the regenerated catalyst even showed better catalytic performance of the MTO reaction than the fresh one. Besides, the calcination regeneration can eliminate coke more completely, however, the methanol leaching method can be more easily carried out in situ in the reactor.