焦化分馏塔下游过滤器中焦炭形态的分析及改进措施

中国石油独山子石化公司1.2 Mt?a延迟焦化装置分馏塔塔底过滤器内的焦炭形态有片状焦和粉末状焦两种形态。通过对这两种焦炭形态进行分析,发现片状焦是由焦炭塔换塔后小吹气造成的大油气线内焦层剥落而产生的焦片,粉末状焦是在焦炭塔生焦后期及换塔后被焦炭塔内泡沫层携带到分馏塔的焦粉。应将粉末状焦留在焦炭塔内,避免进入分馏塔。换塔后,随着大油气线管壁温度的降低,大油气线内壁产生的焦炭会自动剥落。通过调整焦炭塔换塔后的操作,进一步实现了焦炭塔大油气线内片状焦的剥落;通过将分馏塔塔底过滤器换大、换型和操作调整,分馏塔塔底循环油过滤器SR-109B的运行周期最少可以达到32天,SR-109A则可以达到4年;通过调整不同生焦阶段消泡剂的注入量,可以减少焦炭塔焦粉携带量,进一步延长分馏塔塔底循环系统运行周期。

ANALYSIS OF COKE MORPHOLOGY IN FILTERS DOWNSTREAM OF COKING FRACTIONATOR AND COUNTERMEASURE

There are two forms of coke（flake and powder）found in filters downstream of coker fractionator in 1.2 Mt/a delayed coking unit in PetroChina Dushanzi Petrochemical Company.It is found that the flake coke is from the spalling of the coke layer in large oil and gas pipeline due to a small blow after the coke drum switching； while the powdered coke is from the foam entering the fractionator at the EOR of coking drum and after drum changing.Therefore，preventing the coke powder from entering the fractionator and reducing the wall temperature of large oil and gas pipeline to promote the coke spalling on the tube wall is the key to solve the problem.Adjusting coking drum switching operation is an effective measure to promote further the spalling of coke in large oil and gas lines.The filter SR-109B downstream of the coking drum is switched to a larger filter and the filter SR-109A is changed to a new horizontal-back flush filter，respectively，and the coking drum operation conditions are adjusted as well.The results indicate that the SR-109B can run for 32 days and the SR-109A reaches 4 years long.By adjusting the defoamer injection at different stages of coking drum operation，the coke powder entering the fractionator can be reduced further，resulting in much longer operation period of the filters.