Aghamohammadi Sogand, Haghighi Mohammad, Ebrahimi Alireza
Chemical Engineering Faculty, Sahand University of Technology, P.O. Box 51335-1996, Sahand New Town, Tabriz, Iran; Reactor and Catalysis Research Center (RCRC), Sahand University of Technology, P.O. Box 51335-1996, Sahand New Town, Tabriz, Iran.
Chemical Engineering Faculty, Sahand University of Technology, P.O. Box 51335-1996, Sahand New Town, Tabriz, Iran; Reactor and Catalysis Research Center (RCRC), Sahand University of Technology, P.O. Box 51335-1996, Sahand New Town, Tabriz, Iran.
Ultrason Sonochem. 2019 May;53:237-251. doi: 10.1016/j.ultsonch.2019.01.009. Epub 2019 Jan 11.
Fluidized bed reactor and continuous catalyst regeneration system was proposed to overcome the effects of exothermic methanol to light olefins (MTO) reaction and achieve longer lifetime. The proper catalysts for fluidized bed reactor were usually prepared via spray drying method. The shaping of SAPO-34 with the matrix of kaolin and alumina sol binder was selected to prepare in spray dryer and test in fixed and fluidized bed reactor. The main properties of spray dried catalysts such as attrition resistance and micro-spherical morphology are necessary as well as good catalytic performance. The effects of ultrasound power on solid-liquid slurries were examined by the consideration of structural and catalytic properties of the spray dried catalysts. Ultrasound application for the slurries prior to spray drying leads to different particle size distributions and dispersion. Various models of particles assembly were obtained and discussed by XRD, FESEM, NH-TPD, EDX, BET-BJH and FTIR techniques. Pore volume was increased by the application of lower ultrasound power. Its detailed analysis showed that 22 and 78% of the pore volume increase comes from the micro and mesopores, respectively. Ultrasound application prior to spray drying mostly have influence on the arrangement of particles resulted in mesopore volume enhancement. Formation of spherical and symmetric shaped particles is enhanced at the lower power of 45 W but it was not acceptable for the higher power of 90 W. The catalyst which was sonicated at the optimized power demonstrates improvement in physiochemical characteristics but showed higher attrition rate (30% increase compared to non-sonicated one). The catalyst experienced ultrasound irradiation prior to spray showed lower MTO reaction life time (432 min) as it was reported to be 850 min for non sonicated catalyst. Shorter life time of KSAPO-HU (P = 45) can be attributed to its lower mechanical strength.
提出了流化床反应器和连续催化剂再生系统，以克服甲醇制低碳烯烃（MTO）放热反应的影响并实现更长的使用寿命。用于流化床反应器的合适催化剂通常通过喷雾干燥法制备。选择用高岭土和氧化铝溶胶粘结剂作为基体对SAPO-34进行成型，在喷雾干燥器中制备并在固定床和流化床反应器中进行测试。喷雾干燥催化剂的主要性能，如耐磨性和微球形貌以及良好的催化性能都是必需的。通过考虑喷雾干燥催化剂的结构和催化性能，研究了超声功率对固液浆料的影响。在喷雾干燥之前对浆料施加超声会导致不同的粒度分布和分散性。通过XRD、FESEM、NH-TPD、EDX、BET-BJH和FTIR技术获得并讨论了各种颗粒组装模型。施加较低的超声功率会增加孔体积。其详细分析表明，孔体积增加的22%和78%分别来自微孔和中孔。喷雾干燥前施加超声主要影响颗粒的排列，导致中孔体积增加。在45W的较低功率下，球形和对称形状颗粒的形成得到增强，但在90W的较高功率下则不可接受。在优化功率下进行超声处理的催化剂在物理化学特性方面有所改善，但磨损率较高（与未超声处理的催化剂相比增加了30%）。喷雾前经历超声辐照的催化剂的MTO反应寿命较短（432分钟），而据报道未超声处理的催化剂的反应寿命为850分钟。KSAPO-HU（P = 45）较短的寿命可归因于其较低 的机械强度。
