Imperial Oil Limited

Canada-Cities Service, Ltd.

Gulf Oil Canada Ltd.

Ontario Energy Corporation

Her Majesty the Queen in Right of Canada, as Represented by the Minister

Her Majesty the Queen in Right of the Province of Alberta, Government of

Other

Petro-Canada Exploration Inc.

Her Majesty the Queen in Right of the Province of Alberta

Thaddeus E Kizior

In the known operation wherein naphtha-diluted bitumen froth is pumped from a scroll-type centrifugal separator to a disc-type centrifugal separator, an improved pumping system is provided. The system comprises at least two centrifugal pumps in series, each operating preferably at an impellor tip speed less than 4000 feet/minute. The invention is based on the discovery that dilution with naphtha greatly increases the emulsification tendency of the froth components; therefore it is necessary to reduce shearing of this stream to keep the solids and water content of the disc product within a desirable limit. This is achieved by using staged pumping and operating the pumps at a relatively low tip speed.

Dilution centrifuging of bitumen froth from the hot water process for

Bitumen froth streamsfrom the primary separation vessel and secondary flotation cells are gravity transferred into one or more columns and heated and deaerated therein by passing them countercurrent to steam. The heated deaerated froth is then pumped with centrifugal pump means to the froth treatment circuit. By deaerating and heating before pumping, the froth is converted from a form difficult to pump to one which is relatively easy to pump.

Deaerator circuit for bitumen froth

A single capacitance vessel is provided to receive the excess heavy phase discharges (normally water) from a bank of disc-nozzle centrifugal separators. The vessel has a reservoir chamber with a weir at one end. The heavy phase streams are delivered into the reservoir of fluid retained in this chamber. In the event there are any hydrocarbons in the heavy phase fluid, the former rise to the surface of the reservoir fluid and pass over the weir, together with some water. An inert gas blanket within the vessel pressurizes the reservoir so that a fluid backpressure is maintained at the discharge outlets of the separators. By use of this system, any fluid returned from the reservoir to the separators (which occurs when the feed to the separators is low in water) is substantially free of hydrocarbons which, if present, would deleteriously affect the operation of the separators. In addition, the fluid passing over the weir is separated by a downstream weir system into hydrocarbon rich and water-rich fractions which are separately recovered.

Capacitance system for heavy phase discharge of second stage centrifugal

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Edmonton, Canada

Thaddeus E Kizior