Studies On The Determination Method Of Heavy Alkylbenzene Sulfonate In Oil

State-of-the-art technology of ASP flooding in Daqing Oil Field, which is used to reduce interfacial tension and the cost, is strong base. The main active substance of it is the heavy aklyl benzenes sulfonate (HABS). So it is of great importance to develop a practical and easy-to-use quantitative analysis method to analyze the content of HABS in the oil..HABS is one of the most important surfactant in the tertiary oil recovery, and it also have some advantages in the property of low interfacial tension, solubilization ability, abundantly available and economy. Therefore, the determination method of HABS in oil has a double significance of economy and realistic. The main component of oil are several alkanes, organic acid or organic base, the latter parts can be extracted with polar-solvent and quantitative analyzed by the method of UV spectrophotometry.We choose n-hexane as a solvent of the oil and use the method of three-wave length UV spectrophotometry to choose three kinds of UV appropriately, so the shift of absorption spectrometry and the influence of quantitative analysis can be ward off by subtracting an absorbance from another absorbance. Then we have maked quantitative analysis on the HABS with different concentration to study on accuracy and precision of the method.After confirming the absorptive wavemeterλ1 of interfering substance in the oil and the absorptive wavemeterλ2 of HABS, we can have the third wavemeterλ3 with graphing method and the formula(ΔA=A2-((λ2-λ3)A1+(λ1-λ2)A3)/(λ1-λ3)). The equation of linear regression could be gotten according to the standard curve ofΔA-C. The concentration range of HABS can be detected is from 6 mg/L to 60 mg/L, or from 0.03% to 0.3% measured by mass. This is very significant to detect the sample of low concentration of HABS. The slope of the standard curve of AA-C is more than 0.999, so the error is about 5% and the standard deviation is between 0.015mg/L and 0.229mg/L, Recoveries ranged from 95% to 105%.In conclusion, the method of three-wave length UV spectrophotometry is convenient, time-saving and accurate for the quantitative analysis of low concentration of HABS.