Experimental investigation of asphaltene deposition in a transparent microchannel

This study is focused on experimental investigation of asphaltene deposition in a vertical transparent microchannel. Heptane-induced asphaltene precipitation is utilized to precipitate dissolved asphaltene particles in crude oil and form asphaltene particles in ambient temperature and standard atmospheric pressure. These asphaltene particles deposit gradually on the surface of microchannels. The key parameters that influence the mechanism of asphaltene deposition are the ratio of crude oil to n-heptane and experimental elapsed time. At a constant flowrate, the amount of asphaltene deposited on a transparent channel wall is quantified using a new flow visualization technique based on reflected light intensity and image analysis. Asphaltene precipitation and deposition strongly affect the reflected light intensity through the change of mixture color. Experimental results show that asphaltene deposition process might follow three stages, (i) small asphaltene particle deposition at the beginning of the experiment, (ii) a rapid and continuous deposition increase after few hours and (iii) a decrease on deposition rate in the system at the end of the experimentation. The experimental results regarding different mixing ratios illustrate that deposition increases with the increasing of the concentration of n-heptane. Continuous asphaltene deposition can be represented by light intensity in terms of experimental elapsed time. An empirical fitting in logarithmic trend is plotted and can be used for further numerical simulations. These results provide useful information on behavior of asphaltene deposition in diverse parameter setting conditions and are useful in developing and validating numerical model.