金属污染的裂化催化剂失活动力学及平衡催化剂活性模型

Models of Deactivation Kinetics and Equilibrium Activity of Catalytic Cracking Catalyst Contaminated by Metals

在确定呈指数形式的平衡催化剂年龄概率密度函数的基础上,考虑催化剂存在活性强度分布,提出金属污染呈现均匀和非均匀两种污染机制。经催化剂失活动力学方程推导,确定了呈两种金属污染机制的V,Ni,Fe和Na金属沉积量影响的平衡裂化催化剂活性或微反活性模型方程。用工业平衡催化剂活性数据进行模型参数估值,确定了金属污染的催化剂失活模型参数。研究结果表明,呈非均匀金属污染的平衡催化剂活性模型具有较高模拟计算精度,沉积金属先污染强活性中心,后污染弱活性中心。V沉积对催化剂活性的影响最大,其次是Ni和Fe,Na的影响最小。模型预测结果显示,平衡催化剂活性或微反活性随着V,Ni和Fe沉积量增加显著降低,随着Na沉积量增加有所降低。

The age probability density exponential function of equilibrium catalyst in commercial fluid catalytic cracking(FCC) unit was determined and the uniform metal contamination mechanism or non-uniform metal contamination mechanism was proposed based on the distribution of activity intensity of catalyst. The model equations of equilibrium catalyst activity or micro-reaction activity affected by metal contamination from V, Ni, Fe and Na were determined through the derivation of catalyst deactivation kinetics. The parameters of catalyst deactivation kinetics were obtained by the data of industrial equilibrium catalyst activity. The results showed that the model with the non-uniform metal contamination mechanism had higher calculation precision, and the deposited metal first contaminated the strong activity sites, then the weak ones. The effect of V deposition on catalyst activity was the biggest and the effect of Na was the smallest, while the effect of Ni and Fe was medium. The model prediction results showed that the activity or micro-reaction activity of equilibrium catalyst obviously decreased along with the increase of the V, Ni, Fe deposition and slightly decreased with the increase of the Na deposition.