The Study On The Distribution Characteristics Of N-Alkanes In Blend Oil With Fuel And Crude Oil

Nowsday, many studies on the identification of oil spill mostly focus on the characteristics of single crude oil, while the report regarding the characteristics of blend oil with fuel and crude is few. Therefore, the characteristics of blend oil with fuel and crude oil were studied and discussed, in order to provide a technical support for identification of offshore oil spill.GC-FID method was used to detect and analyze the n-alkanes in the blend oil with No.1 fuel-crude oil and blend oil with No.2 fuel-crude oil.The influence of blending ratio on the distribution of n-alkanes and the characteristics of n-C17/Pr、n-C18/Ph、Pr/Ph were investigated. On this basis, five samples of blend oil were selected to weathering experiments for 30 days. Then the influence of weathering on n-alkanes distribution and n-C17/Pr、n-C18/Ph、Pr/Ph in different blend ratios of blend oil with fuel and crude were discussed.Regarding blend oil with No.1 fuel-crude oil:n-alkanes distribution of the No.1 fuel and crude oil were quite different, so n-alkanes in this blend oil according to n-C19 as the boundary point were divided into two parts as n-C10～n-C19 and n-C19～ n-C35, and both of the relative contents were linearly related to the proportion of the No.1 fuel. Beause the n-C18/Ph and Pr/Ph of Daqing and No.1 fuel were different, they were excellent linearly correlated to blend ratios. Beause the n-C17/Pr was similar between Daqing and No.1 fuel, that was not affected by the blend ratios. In summer, n-C10 of blend oil with No.1 fuel and crude oil completely lost in weathering fifth days. Weathering to 20 days, n-C11 and n-C12 also completely lost. The n-C13 of blend oil lost 90% after 30 days of weathering. But n-C15～n-C35 were not affected by weathering. The n-C17/Pr、n-C18/Ph and Pr/Ph of blend oil with No.1 fuel and crude oil were almost not affected by weathering. In addition, the effect of season on the distribution characteristics of blend oil with No.1 fuel and crude was investigated. Weathering degree was is more obvious in the higher temperature of the spring and summer than the temperature of the low degree of weathering of the autumn and winter.Regarding blend oil with No.2 fuel-crude oil:Beause n-alkanes distribution of the No.2 fuel、Oman、Dubai and Indonesia were quite different, n-alkanes of blend oil with No.2 fuel and crude according to n-C17 as the boundary point were divided into two parts as n-C10～n-C17 and n-C11～n-C35, and both of the relative contents were linearly related to the proportion of the No.2 fuel. The n-C17/Pr、n-C18/Ph and Pr/Ph of No.2 fuel and crude were different, so they were excellent linearly correlated to blend ratios.In summer, n-C10 of blend oil with No.2 fuel and crude oil completely lost in weathering third days. Weathering to 16 days, n-C11 and n-C12 also completely lost. The n-C13 of blend oil lost 85% after 30 days of weathering. But n-C15～n-C35 were not affected by weathering. The n-C17/Pr、n-C18/Ph and Pr/Ph of blend oil with No.2 fuel and crude oil were almost not affected by weathering.