焦化装置长周期运行的影响因素及措施

结合中国石化上海石油化工股份有限公司延迟焦化装置的实际运行情况,从减少加热炉、焦炭塔大油气管线和分馏塔结焦方面,分析了制约延迟焦化装置长周期运行的主要因素,如原料性质、加热炉炉管平均表面热强度、加热炉出口温度、焦炭塔冷焦吹气量、焦炭塔操作负荷、急冷油和消泡剂注入方式、分馏塔操作等.在此基础上介绍了该装置为了延长运转周期所采取的一些措施,并提出了改进建议.如合理搭配原料;加热炉炉管多点注汽;焦炭塔老塔切换进料后,继续打急冷油20 min,并严格控制吹汽量;将急冷油注入点由焦炭塔顶顶端移到水平大油气管线以下,急冷油由垂直单点注入改为45°三点注入;由塔底循环泵出口引跨线至加热炉出口,以便将分馏塔底沉积焦炭排往焦炭塔;等等.

IMPACT FACTORS OF LONG-TERM OPERATION OF DELAYED COKER AND COUNTERMEASURES

On the basis of delayed coker operation in Shanghai Petrochemical Co.,Ltd.,the major factors affecting the long-term operation of the coker such as feedstock properties,average heat flux of coker furnace tubes'surface area,furnace outlet temperature,amount of coker drum's cold coke blowing gas,coker drum op- erating load,injection of quench oil and defoamer and fractionator operation are analyzed for the purpose of re- ducing coking in furnace tubes,coker drum oil vapor pipelines and fractionator.Effective measures to extend the coker operation are presented and improvements are suggested,such as proper preparation of feedstock, multi-point steam injection into furnace tubes,continuous injection of quench oil for 20 minutes after drum switch-over,control of gas blowing,3-point injection of quench oil at 45 angle,installation of a pipeline from fractionator bottom circulation pump to furnace outlet to recycle the bottom coke deposit to the coker drum,etc.