Demulsification and breaking mechanism of variable quartz concentrates obtained from sand

Abstract

This study reports the efficacy of quartz particles extracted from sand for the destabilization of crude oil emulsions and efficient water removal. Demulsification performance of quartz concentrates obtained from stacked sieves with openings: 75, 125, 250 and 300 μm and quartz quantity varying from 1% to 7% were investigated using the bottle test technique at a temperature of 90 °C. The breaking mechanism of emulsion driven by quartz was analyzed by rheology, Fourier Transform Infrared (FTIR) spectroscopy, X-ray diffraction (XRD), optical microscopy and scanning electron microscopy (SEM). Experimental results showed that the quartz concentrates generated from stacked sieves: 75, 125, 250, and 300 μm had optimal demulsification efficiency (DE) of 98%, 98%, 99%, and 99%, respectively. Moreover, the quartz concentration needed to attain these DEs levels ranges from 3 to 5%. In addition, the performance of quartz as a demulsifier was compared with a commercial demulsifier (ethyl cellulose). Viscosity versus time measurements demonstrated the change in emulsion's viscosity before and after quartz addition. A drastic reduction in the emulsion's viscosity was observed after quartz addition, indicating rupture and coalescence of water droplets. The FTIR and XRD analysis buttressed the functional groups and structural pattern while optical microscope and SEM analysis exhibited the morphology of quartz particles before and after the demulsification processes. A mechanism elucidating the breaking of crude oil emulsion by quartz is proposed. The results indicated that quartz particles processed from the sand will be useful as demulsifiers in the petroleum industry.