Method for controlling flocculant addition to tar sand tailings
AssigneesPetro-Canada Exploration Inc., Her Majesty the Queen in right of the Province of Alberta, Government of the Province of Alberta, Department of Energy and Natural Resources, Alberta Syncrude Equity, PanCanadian Petroleum Limited, Esso Resources Canada Limited, Canada-Cities Service, Ltd., Gulf Canada Resources Limited
InventorsBryan J. Fuhr, Joseph K. Liu
Life of this patent
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Abstract
The hot water extraction process for recovering bitumen from tar sand produces a large volume of solids-laden aqueous tailings as a waste product. The solids in the tailings stream may be flocculated by the addition of time and the components of the stream then separated into a water-free solids phase and a clarified water phase. During flocculation, the zeta potential of the stream is monitored. It rises from an initial negative zeta potential, as the lime is added. Flocculation is terminated when the zeta potential is about zero. At this point, the tailings are in optimum condition for separation into the water-free solids phase and the clarified water phase. Separation is preferably effected by vacuum filtration.
Claims5
In the hot water extraction process, wherein a solids-laden aqueous whole tailings stream, containing coarse and fine solids, is generated as a waste product, the improvement comprising:
- treating said whole tailings stream with flocculating agent to co-flocculate coarse and fine solids and produce settled aggregates thereof;
- simultaneously monitoring the zeta potential of the fine solids left in suspension;
- continuing the addtition of the flocculating agent until said zeta potential is about zero;
- and
- simultaneous with the treating and monitoring, separating the constituents of the stream to produce a substantially water-free solids phase and a substantially clarified aqueous phase.
Dependencies are inferred from the claim text.