Identification Of Oil Spill Species Using Nickel To Vanadium Ratio

The nickel and vanadium elements in the petroleum exist as porphyrin complex form and are not affected by the weathering process,so they have great values on identification of oil spill.Nine kinds of crude oil and two kinds of marine fuel from home and abroad were as the analysis object.All samples were dealt with crucible ashing,the content of Ni and V in oil was determined by GF-AAS,and then figured out Ni/V.The similarity analysis of 11 kinds of single oil was done with Ni,V content and Ni/V as variables,and the influence of short-term weathering on the properties of single oil was discussed.According to the similarity results,Four groups of mixed oils such as heavy marine fuel-Iran,heavy marine fuel-Oman,light marine fuel-Kuwait,UAE-Iraq were defined.The changes of the characteristics of Ni and V in mixed oil before and after weathering were investigated.The results are obtained as follows:(1)By the similarity analysis,the similarity coefficient is higher between the single oil belong to sea facies,that is,the similarity is very good.Although Oman lie in the Middle East,its crude oil show the property of continental facies,the similarity is slightly lower than other Middle Eastern crude oil,and much lower than other continental crude oil.In addition,the similarity coefficients of Daqing,and Malaysia were closed to two kinds of marine fuels,this implies that these marine fuels may be refined from those crude oils.(2)In the weathering processes for a month,the relative standard deviation(RSD)of Ni/V were about 5%for all of single oil.marine fuel and mixed oil.Namely,Ni/V is relatively stable in the weathering process,with strong resistance to weathering.This feature can be used to identify marine oil spill.(3)The Ni/V characteristics of mixed oil are related to corresponding the single oil.The mixture of two marine crude oils exhibited still the characteristics of marine crude oils,The mixture of marine fuel and marine crude oils showed different characteristics with the different mixing ratio.In addition,Ni/V in each kind of mixed oil will increase with the proportion increasing of larger Ni/V single oil.(4)Each blend oil was systematically clustered by N,V and Ni/V.The results show that,The mixed oils with a larger proportion of single oil are easily gathered into one group because of similar Ni,V,Ni/V.In the two weathering process,the clustering result of each mixed oil was basically same between weathering and unweathering,namely,Ni/V is also very efficient for identification of blend oil.