摘要
收集甲醇制烯烃(methanol to olefins,MTO)工业装置上产生的细粉类废催化剂作为原料,经高温焙烧和离子交换等手段预处理脱除催化剂表面积碳和碱金属,恢复部分活性位。将预处理后的废催化剂与一定量的固体硅源进行物理混合并在蒸汽相转移(vapor-phase transport,VPT)条件下再次晶化5 h即可恢复全部活性。通过XRD,NH_(3)-TPD和BET等手段分析表明,VPT二次晶化后废催化剂的结晶度明显提高,强酸酸量和比表面积均达到新鲜催化剂的标准。将恢复活性的废催化剂与黏结剂在水中打浆,浆液经研磨分散后喷雾干燥成微球催化剂。MTO评价结果显示:100%的废催化剂成型剂(XJ-100)与100%的自制新鲜催化剂成型剂(XJ-0)相比,反应寿命延长了13.8%,双烯选择性提高了1%,但其磨耗较差,催化剂表面有明显的裂纹。最后,通过将废催化剂浆液与新鲜催化剂浆液按比例混合的喷雾成型方式,最终可得到物理性质和催化活性均满足工业应用的MTO催化剂。本研究提出的VPT法修复废催化剂活性和混合喷雾再生相结合的方式是一条绿色的废催化剂再生途径,也为蒸汽相转移法的工业化应用提供了一种新思路。
The catalytic activity of fine powder waste catalyst produced from the methanol-to-olefin(MTO) process can be partially recovered by removing the carbon and alkali metals deposited on the catalyst surface, which is realized by some pre-treatment processes including high-temperature roasting and ammonium-ion exchange. Furthermore, the catalytic activity can be completely recovered through physically mixing the pretreated waste catalyst with a certain amount of solid silica and recrystallizing the mixture for 5 h using vapor-phase transport(VPT) method. The test results of XRD, NH_(3)-TPD and BET show that the crystallinity of the waste catalyst is significantly improved after VPT recrystallization;meanwhile, the amount of strong acid and specific surface area are nearly the same as that of fresh catalyst. The VPT-treated catalyst and the binder are mixed and slurried in water. The slurry is ground and dispersed, and then spray-dried into the regenerated microsphere catalyst. The results of MTO performance test show that, compared with the self-made fresh molding catalyst(XJ-0), the regenerated catalyst(XJ-100) has a longer catalytic reaction life(increased by 13.8%) and a higher selectivity for diene(increased by 1%). However, the abrasion resistance of XJ-100 is relatively unsatisfactory, and the catalyst surface has obvious cracks. To solve this problem, the VPT-treated catalyst can be mixed with the fresh catalyst in a certain proportion, and then the mixture is dried by spray method. Hence, the regenerated catalyst whose physical properties and catalytic reactivity both satisfy the industrial application can be finally obtained. The combination of VPT recrystallization method and spray mixing method is a green way to reuse waste catalysts, which provides a new route for the future industrial application of VPT method.
作者
李志宏
李继翔
狄春雨
李晓峰
窦涛
陈胜利
LI Zhihong;LI Jixiang;DI Chunyu;LI Xiaofeng;DOU Tao;CHEN Shengli(State Key Laboratory of Heavy Oil Processing,China University of Petroleum,102249 Beijing,China;Nanjing Chengzhi Clean Energy Company Limited,210047 Nanjing,China;College of Chemistry and Chemical Engineering,Taiyuan University of Technology,030024,Taiyuan,China)
出处
《煤炭转化》
CAS
CSCD
北大核心
2022年第4期64-72,共9页
Coal Conversion
基金
国家自然科学基金资助项目(91534120).
