A new model based on multilayer kinetic adsorption mechanism for asphaltenes adsorption in porous media during dynamic condition

• A new model based on multilayer adsorption kinetic mechanism is proposed to predict asphaltene adsorption in porous media during dynamic condition with more accuracy in comparison with previous models based on monolayer static mechanism.
• The results show that the adsorption process is rate-controlled based on kinetics mechanism in dynamic condition.
• The results show a decrease in the adsorbed amount with an increasing flow rate.
• It can be concluded that the asphaltene type does not have a considerable effect on adsorption.
• It has been found that carbonate sample is more reactive than other porous media sample.

In this work, a new model based on multilayer kinetic adsorption mechanism has been proposed to account asphaltene adsorption in porous media under dynamic condition and the model was verified using experimental data obtained in this work and also with those reported in the literature. In the proposed model two steps are considered for asphaltene adsorption. The first step is taken as adsorption of asphaltenes on the surface of the porous media and the second step is taken as adsorption of asphaltenes on the asphaltenes already adsorbed on the porous media. The Crank-Nicholson method, central difference in space and trapezoidal rule in time, giving second order convergence in time was applied to develop a computer program using MATLAB software. Also, the Rung-Kutta fourth order scheme has been applied to calculate the volume fraction of asphaltene adsorption. The results show that the proposed model based on multilayer adsorption kinetic mechanism of aphaltene with the absolute average deviation 0.7% can predict more accurately the asphaltene adsorption experimental data in comparison to the previous models based on the monolayer adsorption kinetic and equilibrium mechanism. Sensitivity analysis shows that the proposed model is more sensitive to the first step of adsorption than the second step of adsorption. Also, a series of experiments was carried to investigate the asphaltene adsorption using UV–vis spectroscopy in order to study the effect of different parameters on asphaltene adsorption mechanisms during dynamic condition in porous media such as concentration, asphaltene composition, flow rate and type of porous media. The experimental results show that adsorption is controlled by the type of porous media rather than the asphaltene concentration of solution. Also, it was found that the adsorption process in porous media is controlled by kinetics mechanism during dynamic condition.