Asphaltene removal from model oil solution by N doped graphene in a fixed bed column

Abstract

Asphaltene removal in the crude oil industry is a significant issue. It is essential to develop cost-effective adsorbents to alleviate the problems associated with the presence of asphaltene in oil transportation. Performing continuous adsorption experiments assists in getting an insight into the practical application of novel adsorbents. For the first time, N-doped graphene (N-G) was synthesized for asphaltene removal form model oil solution in a continuous adsorption process. X-ray diffraction patterns, transmission electron microscopy, field emission scanning electron, and Brunauer–Emmett–Teller isotherms were used to characterize the prepared sorbents. The synthesized N-G was mesoporous with high porosity and specific surface area of 134 m2/g. The effects of three parameters were investigated: initial asphaltene concentration from 50 to 200 ppm, flowrate at 1–10 mL/min, and bed depth of 5–20 cm. The synthesized N-G was well suited in the asphaltene removal process due to the strong interactions between asphaltene and adsorbent surface arising from the π–π interaction between nitrogen on the N-G surface and the aromatic rings in asphaltene. The highest amount of asphaltene removal occurred at low flowrates and high bed depth while the effect of concentration was less than others. The highest removal amount in the breakthrough curve was achieved at 1 mL/min flow rate. The good removal efficiency even after several cycles of regenerations indicates a considerable potential of reusability. In sum, N-G could be a highly efficient adsorbent for dynamic asphaltene removal on a large scale.