Performance improvement of Ethylene−Vinyl Acetate Copolymer Pour Point Depressant (EVA PPD) by adding small dosages of Laurylamine (LA)
Xue Xia, Chuanxian Li, Guangyu Sun, Keke Zhao, Jie Zhang, Bo Yao, Fei Yang
Abstract
Lauramine is widely considered to be an asphaltene flocculant, but its effect on the modification of crude oil by PPDs has been little studied. In this paper, the effect of LA dosage on the rheology improvement of EVA PPDs (100 ppm) on Qinghai waxy crude oil was investigated through rheological measurement, wax precipitating analysis, granularity test and resins/asphaltenes FTIR analysis. Compared with pure EVA, the compounding of LA and EVA obviously enhances the agglomeration degree and reduces the number of fine wax crystals, thus further enhancing the rheology of the oil samples, and the best performance is at the LA dosage of 200 ppm. At relatively small LA dosages, the LA facilitates the adsorption of EVA molecules on the asphaltene surfaces, which favors the becoming of EVA/asphaltenes composite particles; but at relatively high LA dosages, the LA makes the asphaltenes more aggregated and disturbs the EVA adsorption on the asphaltenes, which is adverse for the formation of EVA/asphaltenes compound particles. The compound particles can serve as wax precipitating templates and significantly influence its morphology, thus further improving the crude oil rheology. In consequence, the rheology improvement of EVA PPDs on Qinghai waxy crude oil first increases and then decreases with increasing the LA dosage.