烟机结垢的成因分析及防范措施

通过对烟机垢物的元素和晶体组成进行表征，分析其形成条件，计算验证并探讨垢物的形成过程，并提出应对防范措施。烟机结垢过程为：极少数原料油滴在反应汽化段内未完全汽化，未汽化油黏附在催化剂细粉表面并缩合生焦；部分焦炭颗粒未在再生器内烧尽，进入烟道后继续燃烧达到细粉的熔融温度，转化为液相黏性物质；携带微量高温熔融粉尘的烟气在三级旋风分离器下料口、烟机叶片等部位受高速离心作用，黏附到易结垢部位，形成无定形垢物。可通过提升原料油喷嘴雾化效果，调整合适的剂油比和系统细粉含量来减少烟机结垢。

CAUSE OF SCALING OF FCC FLUE GAS EXPANDER AND PRECAUTION ANALYSIS

The composition and crystal phase of the scaling sample of FCC expander was characterized. Based on the results, the formation condition of scaling was analyzed and checked by calculating. The cause and precaution measures were thus proposed. The scaling procedure is as follows: Very few drops of raw oil was not fully vaporized but deposited on the catalyst to become coke；few coke solids entered the flue,the combustion continues to reach the melting temperature of fine coke powder, which was converted into liquid viscous substance; the smoke with trace high-temperature molten dust is subjected to high-speed centrifugation at the three-screw feeding mouth, the blade of the smoke expander and other parts, and adheres to the parts that are easy to form scale, forming unshaped scale. Scaling of expander could be reduced by improving atomization effect of feed oil nozzle, adjusting appropriate ratio of catalyst to oil and fine powder content in the reaction-regeneration system.