Lifetime improvement in methanol-to-olefins catalysis over chabazite materials by high-pressure H2 co-feeds
Lifetime improvement in methanol-to-olefins catalysis over chabazite materials by high-pressure H2 co-feeds
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DOI：
10.1038/s41929-018-0125-2
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发表时间：
2018-09-01
期刊：
影响因子：
37.8
通讯作者：
Bhan, Aditya
中科院分区：
文献类型：
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作者：
Arora, Sukaran S.;Ieskens, Davy L. S. N.;Bhan, Aditya
在工业部署的hspo -34甲醇制烯烃转化过程中，减轻催化剂失活是一个关键的挑战。在这里，我们证明了HSAPO-34在次完全甲醇转化中甲醇制烯烃的催化寿命，由催化剂完全失活（类似于15%碳最终转化）之前每个Bronsted酸位点对排出物中碳氢产品的累积周转量决定。与在同等压力下共喂氦气相比，在增加的分压（400-3,000 kPa）下，在进水中与甲醇共喂H-2可以提高效率（类似于2.8倍至bbb70倍）。高压H-2共进料对寿命的改善在甲醇完全转化时比在半完全转化时更为显著。共投料H-2改善了催化剂的寿命，但对C-2-C(4)烯烃的选择性没有任何有害影响，无论入口H-2压力如何，其选择性仍与85%的碳相似。基于氢转移反应中H-2的参与，这些观察结果可以合理化，实际上，促进失活诱导多环物质形成的途径被阻断。
Mitigating catalyst deactivation in the industrially deployed process of methanol-to-olefins conversion over HSAPO-34 is a critical challenge. Here, we demonstrate that lifetime in methanol-to-olefins catalysis over HSAPO-34 at sub-complete methanol conversion, as determined by the cumulative turnover capacity per Bronsted acid site towards hydrocarbon products in the effluent before complete catalyst deactivation (similar to 15% carbon final conversion), can be enhanced with increasing efficacy (similar to 2.8x to >70x) by co-feeding H-2 at increasing partial pressures (400-3,000 kPa) in the influent with methanol compared with cofeeding helium at equivalent pressures. The lifetime improvement in the presence of high-pressure H-2 co-feeds is observed to be more prominent at complete methanol conversion than at sub-complete conversion. The improvements in catalyst lifetime by co-feeding H-2 are rendered without any deleterious effects on C-2-C(4 )olefins selectivity, which remains similar to 85% carbon irrespective of the inlet H-2 pressure. These observations can be rationalized based on the participation of H-2 in hydrogen transfer reactions, and in effect, the interception of pathways that promote the formation of deactivation-inducing polycyclic species.