催化原料的可裂化性能研究

大连石化自渣油加氢装置开工以来,四催化原料主要以加氢渣油作为催化重料,再调合一些二蒸馏馏分油、酮苯蜡下油以及加裂尾油,其中加氢渣油约占80%。催化原料的变化,也造成产品分布的变化,主要是油浆产率明显增加,液化气产率有所下降。采集并分析了6个样品的一般性质、化学组成及平均结构参数,一般性质包括密度、黏度、平均相对分子质量、残炭、馏程;化学组成包括元素组成(C、H、S、N)、微量金属元素组成(Ni、V、Ca等)和四组分族组成(饱和分、芳香分、胶质和沥青质);平均结构参数如fA(芳碳率)、fN(环烷碳率)、fP(开链饱和碳率)、RT(总环数)、RA(芳环数)、RN(环烷环数)、HAU/CA(缩合度参数)和σ(芳香环系周边氢的取代率),通过实验装置评价了不同催化原料的反应性能,并与工业数据进行对比。分析表明:液化气收率、重油收率、总轻油收率及总液体收率等关键指标与原料芳碳率及H/C原子比几乎均呈线性关系;芳碳率及H/C原子比的差异是导致催化原料可裂化性能差异的主要原因。

A Study on Cracking Properties of FCC Feedstocks

Since its startup,PetroChina Dalian Petrochemical Company’s residue hydrogenation unit has been using a catalytic stock based on hydrogenated residue,blended with some secondary distillate,dewaxed oil from ketone-benzol dewaxing units and hydrocracked tail oil.Hydrogenated residue accounts for about 80%.The change in catalytic feedstock has also resulted in a change in product distribution.The biggest change in product distribution is that the yield of oil slurry increased and the yield of liquefied gas dropped slightly.Technicians collected and analyzed the general properties,chemical composition and average structure parameters of six samples.The general properties included density,viscosity,average relative molecular weight,carbon residue,and distillation range.Chemical composition included elementary composition（C,H,S and N）,trace metal element composition（Ni,V,Ca,etc.） and four-component composition（saturates,aromatics,colloid and asphaltene）,average structure parameters such as fA（aromatic-carbon ratio）,fN（naphthene-carbon ratio）,fP（open-chain saturated carbon ratio）,RT（total ring number）,RA（aromatic ring number）,RN（naphthene ring number）,HAU/CA（degree of condensation parameter） and σ（replacement rate of hydrogens around aromatic ring system）.These technicians assessed the reaction properties of different catalyst materials and compared the results with industrial data.Analysis shows that the key indicators such as LPG yield,heavy oil yield,total naphtha yield and total liquid yield are basically linearly correlated with the aromatic-carbon ratio and H/C atomic ratio of feedstock and that the difference between the aromatic-carbon ratio and the H/C atomic ratio is the main factor affecting the cracking properties of catalytic feedstocks.