Preparation and Application of Silica-based Perfusion Packing of Size Exclusion Chromatography for Quantitation of Polyacrylamide inEnhanced Oil Recovery Systems

摘要

The synthesis and characterization of a novel macroporous silica derived size exclusion chromatography (SEC) packing for quantitative analysis of high molecular weight (MW) polyacrylamide (PAM) are presented.Using this packing,a fast,sensitive and reproducible approach for quantitation of super high-MW PAM in demanding enhanced oil recovery (EOR) waters was developed and the effect of synthesis parameters on the properties of resultant materials was investigated.These parameters include salt addition,reaction temperature and duration,activation condition of functional groups on the silica surface,as well as the reaction cycles required for optimal silica modification.Moreover,SEC analysis conditions,such as mobile phase composition,flow rate,detection and sample preparation,were also explored and an optimal analysis protocol was developed.Under this optimized SEC analysis conditions,the synthesized macroporous materials proved satisfactory for quantification of PAM with average MW up to 22 million Daltons.An SEC analysis required less than few minutes with a detection limit of 1 ng,a linear response range of 0.1 to 75 mg/L with squared R value of 0.99 and reproducibility better than 9.2% RSD (relative standard deviation).The analysis of PAM in highly saline oilfield production water containing interfering high MW polymeric surfactants indicated the recovery ranges from 92.5% to 110.1% for 1.0 mg/L PAM and 94.2% to 103.8% for 50 mg/L PAM solution.This study presented for the first time that the reliable quantization of high MW PAM in highly demanding EOR waters can be achieved by SEC.