A comparative experimental evaluation of the performance of additive compounds for inhibition of asphaltene precipitation from crude oil

In this work, the effects of four different chemical inhibitors, namely a polymeric surfactant, synthesized gamma-Al2O3/NiO nanoparticles, epoxy resin, and canola oil to inhibit asphaltene precipitation in three different crude oils collected from various oil fields located in southern Iran. A high-pressure solid detection apparatus was employed to measure the onset point of asphaltene precipitation in crude oils with API ranging between 35 and 38 and various characteristics in the presence of the inhibitors in a wide range of concentrations ranging 0-20 wt. % at a high pressure of 2,000 psi and ambient temperature. The elemental composition of resin and asphaltene fractions in the crude oils was identified using a LEC elemental analyzer. The results showed that all fractions of precipitated asphaltenes were composed of low ratios of H (hydrogen)/C (carbon), which were an indication of large instability. Moreover, the screening experiments showed that the polymeric surfactant inhibitor with a base-nature was more efficacious with most oil samples due to the presence of high content (73%) of resin in this type of inhibitor. Besides, they can be used as a well-candidate for other oils not assessed in this work due to their high polarity and also compatibility with the structure of studied asphaltenes. It was found that the polymeric surfactant gamma-Al2O3/NiO nanoparticles had the highest inhibition performance in comparison with the epoxy resin and canola oil.