苯酐催化剂稳定性的分析

通过单管模式装置和程序升温还原、程序升温氧化等分析方法,研究了邻二甲苯氧化制苯酐催化剂在开、停车过程中的稳定性。有些催化剂在停车状况下,空气通过催化剂床层而导致催化剂中钒价态升高,催化剂活性下降。制备苯酐催化剂时添加适量的助剂铯,提高了催化剂的选择性和稳定性。不同方法制备的苯酐催化剂,钒与铯的合适配比也不同。

Analysis on the Stability of Catalyst for o-Xylene Oxidation to Phthalic Anhydride

Stability of o-xylene oxidation catalyst to phthalic anhydride (PA) during process start-up and shut down in a single - tube reactor was studied and examined. When operation shut down, the valency of vanadium in some catalysts rose owing to penetration of air through the catalyst bed. When cesium was added as a promoter to the phthalic anhydride catalyst, the ratio of vanadium and cesium affected the oxidizability of vanadium in catalyst thus further influenced the stability of catalyst during the process of start - up and shut down;thus,the ratio of vanadium and cesium in catalyst should be appropriately adjusted. Different methods of phthalic anhydride catalyst preparation determined different vanadium and cesium ratio.