Demulsification of water/crude oil emulsion using natural rock Alginite

Chemical demulsifiers are commonly applied to demulsify stable crude oil/water emulsions formed during production, extraction and transportation. The present work was carried out using a new demulsifying agent based on natural Alginite, a crude oil shale from Hungary. A model W/O emulsion, which was stable over 2 months, was prepared from 50 wt.-% crude oil (Brent type) and 50 wt.-% of brine. This emulsion was successfully split by an addition of 0.5 wt.-% Alginite within one minute. Emulsion viscosity and water content decreased and water droplet size increased rapidly after addition of Alginite verifying the demulsifying effect. After two hours, the water content of the oil was below 1 wt.-%. Alginite recycling succeeds by thermal treatment. When Alginite was calcined up to 1000 degrees C, demulsification efficiency decreased compared to the native material. Experiments with mildly thermally treated Alginite (500 degrees C), which still contains carbonates, showed that the kerogen contained in natural Alginite contributes to demulsification significantly. Chemical analysis of the separated oil showed conformity with industrial specifications.