延迟焦化装置掺炼脱油沥青问题分析与对策

洛阳石化1400kt/a延迟焦化装置由洛阳石化工程公司设计,采用“可灵活调节循环比”工艺流程.随着原油加工量的逐年提高,该装置开始掺炼脱油沥青.这固然可以扩大洛阳石化重油平衡能力,增加重油加工灵活性,提高总体经济效益,但焦化装置掺炼脱油沥青后,由于原料性质变差,随之产生加热炉炉管结焦速率加快、大量生成弹丸焦以及油气携带焦粉等问题.结合焦化原料特点、热反应生焦机理和延迟焦化工艺特点,对延迟焦化装置掺炼脱油沥青造成的影响进行分析.提出优化措施:在溶剂脱沥青装置脱油沥青出装置管线增上渣油、油浆静态混合器,按照一定的比例,使脱油沥青和减压渣油、油浆充分混合,降低原料中的沥青质含量；加强原料监控,改善焦化原料性质,降低加热炉出口温度,提高加热炉管内流体线速,适当加大循环比,保证装置的安全运行.

An Analysis of Problems in Blending Deoiled Asphalt in Feedstock for Delayed Cokers and Countermeasures

Sinopec Luoyang Company＇s 1400kt/a delayed coking unit,designed by Luoyang Petrochemical En- gineering Company,uses a process ＂allowing for flexible adjustment to recycle ratio＂.As crude runs increase yearly,Sinopec Luoyang Company has begun to blend deoiled asphalt in the feedstock for the unit.This mea- sure can enhance the company＇s residual oil balancing ability, increase its flexibility of processing residual oil and raise overall economic benefits.However,after deoiled asphalt was blended in,as the quality of feedstock has deteriorated, a host of problem arose such as faster coke deposition in the tubes of the heating furnace, production of a large amount of shot coke and the entrapment of powdered coke in oil and gas.Based on the characteristics of coking feedstock ,the coking mechanism of thermal reactions and the delayed coking pro- cess,this article analyzes the effect of blending deoiled asphalt in the feedstock for a delayed coking unit and proposes a series of optimizing measures ,including adding a static residual oil and slurry mixer on the line for deoiled asphalt coming out of the solvent deasphalting unit to fully mix deoiled asphalt,vacuum residuum and oil slurry in an appropriate proportion and to reduce the content of asphaltene in the feed- stock ,strengthening feedstock monitoring,improving the quality of coking feedstock ,reducing the temperature at the outlet of the heating furnace ,increasing the linear speed of the fluid in the tubes of the heating fur- nace, and properly increasing the recycle ratio to ensure a safe operation of the unit.