Effect of precipitant on the Asphaltenes PrecipitationBehavior in Capillary Tube

Asphaltenes being the most polar and heaviest composition of crude oil may be destabilized and deposit during the oil production from extraction to refining processes. Asphaltenes deposition induces many problems such as tube plugging and can lead to significant loss of quality and production. There are several publications in the literature discussing prevention of asphaltene deposition using innovativetechnologies. In this study, we first measured the onset of asphaltene precipitation and then this process was examined at some different n-heptane contents as precipitant for further consideration. We pumped the heptane and crude oil in the tube with 0.04 cm inner diameter, 3.212 m length and 12.5 ml/hr volumetric flow rate. 40, 50, 60 and 76 volume percentage of heptane were utilised to precipitate asphaltenesdepositing on inner surface of tube. We then monitored pressure drop to understand the mechanism of asphaltene deposition at various heptane content. Excess pressure drop due to asphaltenes deposition as ΔP- ΔP0 was directly plotted over time as material is injected into the capillary tube. As deposition occurs, ΔP- ΔP0 variation reflects decreases in the pipe radius, signaling deposition. According to the experimentalresults it was found that precipitant content affected on asphaltenes deposition and it has a direct relationship with asphaltenes deposition. It was found that if the oil-heptane mixture is monitored over time, asphaltene precipitates occur in lower concentrations rather than the instantaneous onset point.

کلیدواژه ها:

Asphaltene ، Deposition ، onset point ، precipitant content