延迟焦化装置弹丸焦的研究进展

Research on shot coke in delayed coking units

介绍了弹丸焦的形态、特性、判断方法及危害等。根据工业生产情况,对弹丸焦的生成与原料性质及操作条件进行了初步关联。当原料油比重指数<7、残炭与沥青质之质量比值<1.4,或当原料油经420℃维持20 min后所得残渣油的残炭与沥青质之质量比值<2.0、所得甲苯不溶物质量收率>7%、所得残渣油的微残炭值>21%,极易产生弹丸焦。对于劣质原料油,当焦化温度≥495℃、循环比≤0.25、焦炭塔内压力≤0.15 MPa、焦炭塔内气速≥0.16 m/s,极易产生弹丸焦。在此基础上提出避免生成弹丸焦的措施:优化原料性质,改善操作条件。最后指出研究弹丸焦存在的困难及应重点研究的工作:①确认生成弹丸焦的原料性质;②试验研究装置模拟工业生产装置,确认生成弹丸焦的操作条件;③模拟工业生产条件开展成焦试验,快速分离成焦过程中实时所得的中间相物质并检测其形态结构及物质特性,探讨弹丸焦的生焦机理。

The property of vacuum residuum becomes increasingly poorer with deterioration of crude oil quality, which greatly affects the coking performance. The possibility of shot coke production from inferior vac uum residuum is rising. The shot coke formation will have a serious impact on safe reliable operation of the unit. Whereas, the shot coke product is of poorest quality and can only be used as fuel for electric power gen eration. Although there are some descriptions reported about the coke formation, there is no analysis on the mechanisms of shot coke formation. This paper introduces the form, characteristics, judgmental method and hazards, ete of the shot coke. Based upon the commercial unit operation, the feedstock properties and operat ing conditions for shot coke formation are preliminary concluded and control measures are recommended. On this basis, difficulties of studying shot coke are analyzed such as （1） difficulty to determine the feedstock prop erties for shot coke formation, （2） difficulty to simulate commercial process in pilot plant, （3） difficulty to have a realtime analysis of whole process of shot coke formation. The required work activities are presented such as ： （1） development of analytical method of shot coke, （2） study on feedstock property for shot coke formation, （3） study on operating conditions of shot coke formation, （4）study on shot coke formation process by fast separa tion of intermediate phase material.