The micro-explosion strength of emulsified heavy oil droplets in catalytic cracking process

Abstract

The emulsified feedstock technique applies the secondary atomization mechanism to heavy oil catalytic cracking process, which can significantly improve the atomization of feedstock and result in a more desirable product distribution. A model of micro-explosion strength of emulsion droplets in riser reactor is proposed in this paper. Model calculation shows that the superheat limit of emulsified heavy oil is 307.7°C at atmospheric pressure, and the micro-explosion strength increases with the size of dispersed water sub-droplets. The theoretical prediction was validated experimentally through feedstock emulsification tests and catalytic cracking experiments. Results indicate that with an increase of the water content in feedstock emulsification, the size of dispersed water sub-droplets in emulsified oil rises, and thus the micro-explosion strength of emulsion droplets in riser reactor increases, which results in a higher light oil yield and lower coke and dry gas yields of catalytic cracking. Compared with pure heavy oil feedstock, the light oil yield rises by 2%, and the yields of coke and dry gas decline by 1.23% and 0.17% respectively for emulsified feedstock at 5% water content.