废FCC催化剂复活再生及结构变化研究

Regeneration and Micro-Structure Change of Spent FCC Catalyst

采用混酸控制浸出除Ni,Fe,保留催化剂酸性组分Al_2O_3,再附载稀土金属活化的方法对废流化催化裂解(FCC)催化剂再生复活研究,通过傅里叶红外光谱(FI-IR)、X射线衍射(XRD)、扫描电镜(SEM)和X射线能谱(EDAX)技术对废催化剂再生中基团结构的形貌、物相、化学成分含量进行了表征;探讨了废FCC催化剂再生过程中微观结构变化及对再生过程中废FCC催化剂性能的影响。考察了酸度、温度、时间等条件对废FCC催化剂中除Ni,Fe的效果及RE_2O_3,Al损失的影响。实验结果表明:当混酸(乙二酸、乙酸)质量分数为1%,反应温度为50℃,反应时间为50 min时,RE_2O_3,Al的损失最少,Ni的去除率达到45.0%,Fe的去除率达到88.1%。对除Ni,Fe损失的RE_2O_3在水溶液中附载处理,焙烧再生的废FCC催化剂的比表面积为290 m2·g-1,结晶度26.6%,4 h微反活性76.2%,产品的性能接近新鲜FCC催化剂性能。

Mixed acid was used to remove Ni and Fe via controlling leaching, and reserve A12O3 , the acidic component of catalyst. Then the regeneration of spent fluid catalytic cracking catalyst was studied by reabsorbing rare earth metals. The micro-structure, mor-phology and chemical composition of regenerated catalyst were characterized by Fourier transform infrared spectroscopy （FT-IR） , X- ray diffraction （XRD） , scanning electron microscope （SEM） , and energy dispersive X-ray analysis （EDAX）. The change of mi- cro-structure and the effect on the properties of spent FCC catalyst during the regeneration were discussed. The effects of acidity, temperature, time and other conditions on removal of Ni, Fe and the loss of RE2O3 and A1 were investigated. The results showed that the loss of RE2O3and Al was the least, the removal rates of Ni and Fe could be 45.0% and 88.1% , respectively, when the mass fraction of mixed acid （ oxalic acid, acetic acid） was 1% , reaction temperature was 50℃, and reaction time was 50 rain. The lost RE203 when removing Ni and Fe was loaded in aqueous solution. The specific surface area of regenerative catalyst was 290 m^2·g^-1, the crystallinity was 26.6% , and the micro-reactivity of 4 h was 76.2%. The properties of regenerated catalyst were close to fresh FCC catalyst.