Packed-bed microreactors for understanding of the dissolution kinetics and mechanisms of asphaltenes in xylenes

Abstract

Insightful information concerning the dissolution of asphaltenes in quartz porous media was acquired through the use of transparent packed-bed microreactors (μPBRs), inline UV–vis spectroscopy and pressure transducers. Experimental results showed that longer shut-in time (16h) facilitated the removal of asphaltenes, but the dissolution rate constants decreased gradually. At larger ReP values of 5.52×10-2, less time was allowed to dissolve asphaltenes and as a result less asphaltenes were removed. At a higher n-heptane volume composition of 80vol%, more low molecular weight asphaltenes were deposited in μPBRs but were easier to dissolve. At temperature range of 25–90°C, more asphaltenes were removed as increasing temperature. Estimation of permeability–porosity relationships indicated that even when ~70–90wt% asphaltenes were removed from the damaged packed-bed microreactors (DμPBRs), the permeability impairments were still much lower than expected. The remaining asphaltenes in the DμPBRs plugged the pore throat of porous media, and as a result resisted the flow of fluids. Understanding the dissolution kinetics and mechanisms of asphaltenes in porous media can be useful in designing remediation treatments that minimize production losses and the resultant economic losses.