催化裂化装置中催化剂平衡活性的数学模拟

MATHEMATICAL SIMULATION OF CATALYST BALANCE ACTIVITY FOR CATALYTIC CRACKING UNIT

依据催化裂化催化剂水热失活过程伴随着超稳化过程,确定了催化剂自抑制水热失活动力学模型方程。利用催化裂化催化剂水热失活实验数据进行参数估值,确定了模型参数,以及模型参数与老化温度和水蒸气分压的关联式,建立了催化裂化催化剂水热失活动力学模型。考虑工业装置中催化裂化催化剂呈全混流,建立了催化裂化催化剂平衡活性数学模型,并且成功地模拟计算了装置平衡催化剂的微反活性。该模型的预测结果表明,随着再生器温度或催化剂藏量的提高,平衡剂的微反活性逐步降低;平衡剂微反活性随催化剂单耗的增加而提高,但提高的幅度逐渐降低。

The kinetic model of hydrothermal deactivation and the model of unit balance activity for FCC catalyst were established. At first, considering catalytic cracking reaction as secondorder reaction, the catalyst activity relating to hydrothermal deactivation was expressed as the ratio of cracking reaction rates on hydrothermal aged catalyst and new catalyst. The kinetic model equations of hydrothermal deactivation for self-resistance were determined by considering that the catalyst hydrothermal deactivating went on together with the catalyst ultrastabilization. Then, the hydrothermal deactivation kinetic models for self-resistance were developed through parameter estimations based on the steam aging experimental data of FCC catalyst. The results of statistics analysis showed that the calculation precision of first order deactivation kinetic model with second order self-resistance factor was high. And, the kinetic model parameters were correlated with catalyst steam aging temperature and steam fraction pressure. In other way, based on the flow properties of complete stirred-tank reactor, the model of FCCU balance activity was developed. It was pointed out that the observed data of micro-reaction activity for FCCU balance catalyst was conformable to the data calculated by the model of unit balance activity. The prediction results of the balance activity model showed that the micro-reaction activity of the FCCU balance catalyst increases quickly along with catalyst consumption, but the increase slowed down. In the end, the higher the regenerator temperature or the larger the catalyst content of regenerator, the lower the micro-reaction activity of FCCU balance catalyst.