大庆蜡油催化裂化过程中的质子化裂化反应

Protolytic cracking in Daqing VGO catalytic cracking process

在小型固定流化床装置上采用酸性催化剂进行了多系列不同反应深度的催化裂化实验,对大庆VGO催化裂化过程中发生的质子化裂化反应进行了初步的研究。在重质油的催化裂化过程中会出现二次质子化裂化反应。二次质子化裂化反应主要是由于汽油中烷烃重新在酸性催化剂上形成五配位正碳离子随后分解所造成,其产生的原因主要是由于反应后期催化剂对反应中间产物的选择性吸附改变所致。二次质子化裂化反应对温度不敏感。大庆VGO在500℃下反应时二次质子化裂化反应约占整个质子化裂化反应的60%。

The prototytic cracking of Daqing vacuum conducting multiple series of experiments from the low gas oil （VGO） catalytic cracking process was studied by reaction conversion to high conversion over acid catalyst in a small fixed fluid bed （FFB） unit. A concept of the secondary protolytic cracking is proposed for VGO catalytic cracking process. The reactants of the secondary protolytic cracking are mainly paraffins in naphtha that are readsorbed on the acid catalyst and then cracked subsequently. The primary reason that causes the secondary protolytic cracking is the change of selective adsorption of the intermediate products on catalysts at the late reaction stage. The secondary protolytic cracking is not very sensitive to the reaction temperature. The portion of the secondary protolytic cracking in the whole protolytic cracking process is 60% for Daqing VGO at 500 ℃.