催化裂化装置输送斜管内催化剂流化状态分析

斜管是催化裂化装置催化剂循环的输送管，催化剂在斜管内保持良好的流化状态是装置平稳运行的关键之一。在某3.3 Mt/a 催化裂化装置上，通过测量再生斜管的轴向压力分布和滑阀前催化剂的表观密度，分析斜管内气体和催化剂的流动状态。结果表明：斜管下部形成了填充流，摩擦损失压降显著上升，是轴向压力分布发生逆转的主要原因。根据斜管内气体流动方向，将斜管流化状态划分为3个区，Ⅰ区为负压差脱气段；Ⅱ区为负压差持气段；Ⅲ区为正压差持气段。通过调整合适的松动风量，可以改变催化剂的流化状态。

ANALYSIS OF CATALYST FLOW PATTERNS IN CONVEYING INCLINED TUBE OF FCC UNIT

Inclined tube is the conveying pipe for catalyst circulation in FCC unit. Catalyst flowing smoothly in the pipe is one of the key points for the steady operation of the device. The fluidized states of the catalyst and gas in the inclined tube of a 3.3 Mt/a FCCU were analyzed by measuring the axial pressure profiles of the regenerator inclined tube and the catalyst apparent density in front of the slide valve. The result showed that the dense-phase flow was formed in the lower part of the pipe, resulting in a significantly increased friction pressure drop, which is the main cause for the reversal of axial pressure distribution. Inclined tube operation was divided into three parts according to the direction of gas flow: Part I was the negative pressure differential degassing region; Part II was the negative pressure differential gas holding region; Part III was the positive pressure differential gas holding region. The fluidized state of catalyst can be changed by adjusting aeration rate.