辽河超稠原油延迟焦化不产生弹丸焦工艺条件探索

中国石油天然气股份有限公司辽河石化分公司1．0Mt／a延迟焦化装置加工辽河超稠原油。由于辽河超稠原油密度大、盐含量高，焦炭塔焦炭中经常出现大量的弹丸焦，导致焦炭塔放水不畅，严重时堵塞放水管道。为此，通过工业试验考察了加热炉出口温度、进料金属含量、循环比、焦炭塔操作压力对弹丸焦形成的影响，得到了基于辽河超稠原油的适合该装置特点的不产生弹丸焦与黏焦的合适工艺条件，并绘制出了寻找合适加热炉出口温度、循环比及焦炭塔塔顶压力的工作曲线。工业试验数据表明，弹丸焦的形成不仅与工艺条件和进料的沥青质含量有关，进料的金属含量过高同样会加速弹丸焦的生成。与一般实验室结果不同的是，工业试验数据表明，降低循环比反而有利于减少弹丸焦的生成，这一发现应引起同行重视。

Study on operation conditions for producing no shot coke in extra-viscous crude oil delayed coking unit

The 19 000 b/d delayed coking unit in PetroChina Liaohe Petrochemical Company is operating to process Liaohe viscous crude. As Liaohe viscous crude is high in density and salt, a large amount of shot coke was produced, which affected the flow of blowdown water of coker drum and blocked the water pipelines. To solve the problem, commercial experiments have been conducted, the impacts of furnace outlet temperature, feed metal content, recycle ratio, eoker drum operating pressure on the formation of shot coke have been studied, the appropriate process conditions for producing no shot coke and sticky coke have been generated, the operating curves of furnace outlet temperature, recycle ratio and coker drum overhead pressure have been produced. The commercial experiment data show that the formation of shot coke is closely related with process conditions, asphaltene content while the higher metal content also accelerates the shot coke formation. Contradictory to the laboratory tests, the commercial experiment data also show that the reduced recycle ratio is favorable to the reduction of shot coke formation, which needs attention of oil refiners.