高效再生器催化剂循环速率的计算

CALCULATION OF CATALYST RECYCLE RATE OF FCC REGENERATOR WITH FAST FLUIDIZATION

提出了计算催化裂化高效再生器催化剂内循环速率的两种方法:烧焦罐底部热平衡法和稀相管压力降法.对实际工业装置标定数据进行计算表明.用热平衡法计算得到的催化剂循环比值(催化剂内循环速率与两器循环速率之比.)在10以上,不符合实际情况,主要是由于烧焦罐内存在轴向返混。实测的烧焦罐底部温度高于待生剂、再生剂和主风的混合温度.因此,推荐采用稀相管压力降法计算催化剂内循环速率.该法计算简单,结果可靠.还考察了催化剂循环比对烧焦罐再生效果的影响,提高循环比可以提高再生温度,但降低了催化剂混合时平均碳含量.总的再生效果有一最优循环比,在所考察的工业条件下为1.0～1.5.

Two calculation mothods of the catalyst recycle rate between the second stage and the fast fluidizer of the regenerator with fast fluidization, heat balanced method and pressure drop method, were introduced and discussed. The catalyst recycle ratio (the ratio of the catalyst recycle rate between the second stage and the fast fluidizer to that between reactor and regenerator) calculated with the heat balance in the bottom of the fast fluidizer was more than 10. It was not acceptable, because the temperature in the bottom of the fast fluidizer was higher than the mixing temperature of the spent catalyst from the reactor, regenerated catalyst from the second stage and main air for burning coke. The dilute phase pipe pressure drop method was recommended, the effect of the catalyst recycle ratio on the regeneration of the fast fluidizer was studied with FCC Regenerator model. Increasing the catalyst recycle ratio could increase the temperature of the fast fluidizer of the regenerator, and decrease the mixing coke content. An optimizied catalyst recycle ratio was found for commercial FCC unit to be between 1. 0 and 1.5.