Search

In order to provide valuable information for the separation process of petroleum sulfonate and the mixing rule of petroleum sulfonate components, the methods of water extraction and column chromatography were used to separate non-sulfonated oil and petroleum sulfonate components, respectively. The effects of oil separation rate, source of crude oil, and composition of petroleum sulfonate on oil–water interfacial tension (IFT) were investigated. The results showed that the oil–water IFT of petroleum sulfonate products for oil displacement was affected by many factors. The presence of a small amount of non-sulfonated oil in petroleum sulfonate had positive synergistic interaction on the reduction of IFT. Reasonable mixture of petroleum sulfonate components with different polarities could avoid chromatographic separation and improve the interfacial activity of products. When the oil separation rate was 70%, the IFT between oil and water was the lowest, which served as a reference for the separation of non-sulfonated oil. Under the same oil displacement conditions, crude oil from different blocks had a greater impact on oil–water IFT. The ultra-low IFT appeared when intermediate petroleum sulfonate and water-soluble petroleum sulfonate were compounded with 3:1. [ABSTRACT FROM AUTHOR]

The non-sulfonated oil in industrial petroleum sulfonate was separated by centrifugal method and extraction method, respectively. The oil separation rates of each method were compared, and the effects of oil separation rates under different conditions on the purity of non-sulfonated oil were investigated. The purity information of non-sulfonated oil separated by different methods was analyzed by infrared spectroscopy. The experimental results showed that the oil separation rate of centrifugation was low, and the oil extraction rate was higher. The purity of non-sulfonated oil separated with alcohol–water solution as extractant was lower, while the purity of non-sulfonated oil separated by water extraction method was the highest, and the extractant was nontoxic and environmentally friendly. Water was preferred as extractant. Solvent ratio, temperature and pressure all had great influence on oil separation rate. The optimum conditions for SL petroleum sulfonate were: solvent ratio 1.5:1, 90 °C, atmospheric pressure, which the oil separation rate was 78.51%; and for DQ petroleum sulfonate, the optimum conditions were: solvent ratio 2:1, 90 °C, atmospheric pressure, which the oil separation rate was 79.86%. Non-sulfonated oil separated by water extraction had the least petroleum sulfonate, followed by ethanol single solvent extraction. Although the extraction efficiency of isopropanol aqueous solution and n-pentane was the highest, the content of petroleum sulfonate in non-sulfonated oil was the highest, which affected the product performance and should not be used. [ABSTRACT FROM AUTHOR]

The influence of slug flow on local corrosion of pipeline was studied, and the protection measures for slug flow corrosion were well done to improve the safety of oil-gas-water-humidity mixed pipeline. An indoor loop test was designed to simulate the slug flow in real undulating pipelines. The surface microstructures of X70 hanging pieces were studied by scanning electron microscopy (SEM) under slug flow conditions at different test stages. At the beginning of the test, there was much pitting corrosion on the surface of the hanging pieces, but at the end of the test, only some pitting or pitting spots developed into serious local corrosion. The flow corrosion of slug in pipe had obvious characteristics of cavitation corrosion. Its occurrence was the result of synergistic action of various mechanisms. The strong impact force, high impact velocity and mechanical action of multi-frequency micro-jet produced by cavitation annihilation significantly affected the development process and characteristics of electrochemical corrosion, which resulted in that the cavitation corrosion was mostly pitting corrosion. The damage of corrosion product film caused by high-speed micro-jet impact caused by cavitation cracking was local, and the pitting tendency increased at the local damage of corrosion product film. However, with the formation of electrochemical corrosion products, the destroyed corrosion product film was repaired continuously, but did not develop into local corrosion. Local corrosion occurred only when the high-speed micro-jet with cavitation breakdown repeatedly impacted a point of pitting tendency, but this probability was smaller than that of pitting tendency. [ABSTRACT FROM AUTHOR]