Abstract: The down-flow part of the catalyst circulation loop in methanol to olefin (MTO) unit is the regeneratr standpipe, which is the precondition to ensure the normal operation of the MTO unit. It has become the bottleneck of the high efficient operation of the regenerator standpipe of a 0.60 Mt/a MTO unit that the catalyst transfer is not smooth. So the reasons of the catalyst transfer were analyzed by measuring the axial pressure distribution and process parameters of the regenerator standpipe. The results show that due to the degassing of the catalyst and the large gas bubbles, the flow patterns of transition filling flow, slug flow and dense-phase flow are formed from top to bottom in the fluidized state of catalyst transfer in the regenerator standpipe, leading to the content of catalyst and the amount of catalyst cycle fluctuating greatly. Based on the analysis results, some suggestions were proposed for structural modification of regenerator standpipe.

Key words: MTO, regenerator standpipe, catalyst transfer, flow pattern analysis, pressure measurement