大型炼化一体化项目炼油加工方案的优化研究

Study on optimization of refinery processing schemes for large-scale refining-chemical integration project

关键词:  炼油加工方案  炼化一体化  柴油加氢裂化  连续重整  柴汽比  乙烯裂解  对二甲苯

Key words:  refinery processing scheme  refining-chemical integration  diesel hydrocracking  continuous reforming  the diesel to gasoline ratio  ethylene cracking  p-xylene

摘要:

目的 在国内某1 500×10⁴ t/a炼化一体化项目中新建100×10⁴ t/a乙烯裂解装置及80×10⁴ t/a对二甲苯装置,设计与原1 200×10⁴ t/a炼油项目及新建300×10⁴ t/a炼油改扩建项目相匹配。项目实施后,全厂柴汽比偏高,成品油总量偏多；乙烯裂解原料不足,且组分偏重；对二甲苯装置技术路线竞争力较弱,故需解决装置存在的上述问题。方法 确定300×10⁴ t/a炼油改扩建项目采用新增“220×10⁴ t/a柴油加氢裂化+260×10⁴ t/a连续重整”路线对炼油加工方案进行优化,以增产乙烯裂解及对二甲苯原料。结果 与优化前相比,全厂柴汽比由1.74降至1.00,成品油总量减少187.68×10⁴ t/a；乙烯裂解原料总量约降低1.74×10⁴ t/a,但乙烯产品量增加5.61×10⁴ t/a,乙烯裂解原料进一步轻质化；对二甲苯原料由127.03×10⁴ t/a增至291.69×10⁴ t/a,可满足200×10⁴ t/a对二甲苯装置的要求。结论 采用2017版50美元/bbl(1 bbl=159 L)的原油价格体系,项目增量的投资收益率(税后)为27.62％,具有较好的经济效益。 

Abstract:

Objective sThe new 1.0 Mt/a ethylene cracking unit and 0.8 Mt/a p-xylene unit in a 15.0 Mt/a refining-chemical integration project in China was designed to be matched with the original 12.0 Mt/a refining project and the new 3.0 Mt/a refining reconstruction and expansion project. After the project was implemented, the diesel to gasoline ratio was relatively high, and the total amount of refined oil was too much; the ethylene cracking feedstock were insufficient, and the overall properties were heavy; the competitiveness of p-xylene unit technology route was weak. Therefore, above problems need to be solved. MethodThe route was determined that the refining processing project added "2.2 Mt/a diesel hydrocracking+2.6 Mt/a continuous reforming" to optimize the refinery processing schemes, increasing the feedstock of ethylene cracking and p-xylene. Results Compared with before optimization, the diesel to gasoline ratio decreased from 1.74 to 1.00, and the total refined oil reduced by 1 876.8 kt/a; the total ethylene cracking unit feedstock reduced by about 17.4 kt/a but the ethylene production increased by 56.1 kt/a, the ethylene cracking feedstock were further lightened; p-xylene unit feedstock increased from 1 270.3 kt/a to 2 916.9 kt/a, which could meet the demand of 2 000 kt/a of p-xylene unit feedstock. Conclusion Using the 2017 version of the crude oil price system of 50 US dollars/bbl (1 bbl=159 L), the incremental investment rate of return (after tax) of the project is 27.62%, which has good economic benefits.