甲醇制烯烃装置立管内下行催化剂的压力特性分析

DESCENDING IN STANDPIPE OF METHANOL TO OLEFINS UNIT

针对某工业甲醇制烯烃装置再生立管存在催化剂输送不畅,导致催化剂循环量不稳定、双烯收率和产品分布变差的问题,通过测量再生立管不同位置的动态压力和静态压力,分析立管内气固两相流的流态和压力特性,探讨催化剂输送不畅的原因。结果表明:再生立管内催化剂循环量较低是催化剂脱气较快的主要原因;再生立管内的催化剂流态包括斜管部分的分层流、垂直管顶部的稀相流和下部的密相流;不同流态具有不同的压力特性,可以作为流态识别的依据。另外,对立管内的气固线速进行了计算,气泡运行方向与流态分析结果相一致,可以作为装置进行操作调整的依据。

The regeneration standpipe of an industrial methanol to olefins unit had the problem of poor catalyst transport,which led to unstable catalyst circulation,poor propylene and ethylene yield and product distribution.The flow state and pressure characteristics of gas-solid two-phase flow in the standpipe were analyzed by measuring the dynamic pressure and static pressure at different positions of the standpipe,and the reasons for the poor catalyst transport were discussed.The results showed that the main reason for the rapid degassing was the low amount of catalyst circulation in the regeneration standpipe.The catalyst flow patterns in the regeneration standpipe included stratified flow in the inclined pipe,thin phase flow in the top of the vertical pipe and dense phase flow in the lower part of the vertical pipe.Different flow patterns had different pressure characteristics,which could be used to identify the flow patterns.In addition,the gas-solid linear velocity in the standpipe was calculated,and the bubble direction was consistent with the analysis result of the flow patterns,which could be used as the basis for operation adjustment of the device.