Bitumen froth treating process

Abstract

A process for treating a bitumen froth containing bitumen, solid mineral material and water, including subjecting a first mixture containing the bitumen froth and a first amount of a paraffinic solvent to first gravity separation, thereby producing a first overflow stream and a first underflow stream, wherein the first gravity separation is performed so that the first underflow stream contains between about 5 percent and about 40 percent by weight of the asphaltenes contained in the first mixture. A second mixture containing the first underflow stream and a second amount of the paraffinic solvent is subjected to second gravity separation in order to recover bitumen from the first underflow stream.

Description

TECHNICAL FIELD[0001]A process for treating a bitumen froth to remove solid mineral material and water therefrom.BACKGROUND OF THE INVENTION[0002]Bitumen is typically extracted from surface-mined oil sands by using water-based extraction processes. The mined oil sands are first mixed with hot or warm water to create a slurry, which is then conditioned in a piece of rotary equipment or in a slurry pipeline. Subsequently, the bitumen is separated from the bulk of the mineral material tailings and water in one or more separation vessels to produce bitumen froth.[0003]A typical good quality bitumen froth may be comprised of between about 50 percent and about 70 percent bitumen by weight, between about 10 percent and about 20 percent solid mineral material by weight, and between about 20 percent and about 35 percent water by weight. A typical poor quality bitumen froth may be comprised of relatively less bitumen and relatively more solid mineral material and / or water.[0004]Bitumen froth ...

AI Technical Summary

Benefits of technology

[0027]The first mixture has a first solvent to bitumen ratio. The paraffinic solvent, the first solvent to bitumen ratio, and the temperature at which the first gravity separation is carried out are selected to precipitate or otherwise reject the desired amount of asphaltenes from the bitumen froth and thereby provide a desired amount of cleaning of the bitumen froth without unduly rejecting asphaltenes from the bitumen froth.

[0029]The second mixture has a second solvent to bitumen ratio. The paraffinic solvent, the second solvent to bitumen ratio, and the temperature at which the second gravity separation is carried out are selected to facilitate recovery of bitumen from the second mixture by increasing the difference in density between the bitumen and the other components of the second mixture.

[0031]The third mixture, where applicable, has a third solvent to bitumen ratio. The paraffinic solvent, the third solvent to bitumen ratio, and the temperature at which the third gravity separation is carried out are selected to facilitate further recovery of bitumen from the third mixture by increasing the difference in density between the bitumen and the other components of the third mixture.

[0042]One or more different gravity separation techniques may be used to perform the gravity separation in the invention. Preferably the gravity separation techniques used in the invention are relatively low intensity processes so that disruption and / or interference with components of the bitumen froth (such as clustered or aggregated asphaltenes) is minimized.

[0049]In some embodiments, inclined plate settlers which are used in the invention may be comprised of inclined plates which have been adapted to minimize or eliminate the accumulation of bitumen on the inclined plates.

[0054]Due to the relatively low amount of asphaltene precipitation and / or rejection which results in the first gravity separation, the anticipated vertical settling rate of the rejected material may be less than about 100 millimeters per minute. As a result, the use of an inclined plate settler for the first gravity separation may be advantageous.

Problems solved by technology

The naphthenic process typically results in a relatively high bitumen recovery from the bitumen froth, but also typically results in a relatively high BS&W content in the resulting bitumen product, so that the diluted bitumen product is not particularly “clean”.

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