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研究了Ga2O3/HZSM-5催化剂在乙烷脱氢反应中的积碳、再生以及MgO的修饰作用.通过激光拉曼、TG-MS和NH3-TPD等表征手段对反应过程的积碳种类和速率进行研究.实验结果表明,催化剂强酸中心上容易发生乙烷裂解生成甲烷的副反应并产生积碳,其中石墨型积碳在反应过程中难以消除,是导致催化剂失活的主要原因.MgO修饰可以减少催化剂强酸中心的量,对乙烷裂解生成甲烷的副反应活性起到显著抑制作用,并使积碳速率得到有效控制,从而提高了催化剂的稳定性和乙烯的选择性.催化剂再生时,在空气气氛中加入水蒸气能够提高脱除石墨化碳的效率,经420℃再生后催化剂的活性得到明显恢复.
The carbon deposition, regeneration and the modification of MgO on Ga2O3 / HZSM-5 catalyst were studied.The effects of different types of carbon deposition on the reaction process, such as laser Raman, TG-MS and NH3-TPD, The experimental results show that the side reaction of ethane cracking to methane is easy to happen on the strong acid sites of the catalyst and carbon deposition is produced, of which graphite carbon deposition is difficult to eliminate during the reaction, which is the main reason for catalyst deactivation.MgO modification can Reducing the amount of strong acid sites in the catalyst significantly inhibits the side reaction of ethane cracking to methane and effectively controls the carbon deposition rate to improve the stability of the catalyst and the selectivity of ethylene.When the catalyst is regenerated, The addition of water vapor into the air atmosphere can improve the efficiency of removal of graphitized carbon, and the activity of the catalyst recovered obviously after the regeneration at 420 ℃.