Slurry Treatment Method and Apparatus

Abstract

A method of extracting bitumen from tar sands includes providing an apparatus for mixing fluids, the apparatus including: a housing, a substantially cylindrical rotor rotatably mounted within the interior chamber, a first array of spaced bores formed in the peripheral surface of the rotor, a second array of spaced bores formed in the peripheral surface of the rotor, a first fluid inlet in the housing, a second fluid inlet in the housing, and a fluid outlet in the housing positioned for withdrawal of fluid from the chamber to minimize cavitation damage at the location of the fluid outlet, and providing a separation composition at the second predetermined location, the separation composition including: a wetting agent in the amount of from about 0.001% to about 2.5% by weight of the separating composition, a hydrotropic agent, and a dispersant having flocculating characteristics, wherein the separating composition has a pH greater than 7.5.

Description

FIELD OF THE INVENTION[0001]The present invention relates to extraction of bitumen from tar sands.BACKGROUND OF THE INVENTION[0002]Oil sands, also known as “tar sands” and “bituminous sands,” are a mixture of bitumen (tar), sand, and water. Bitumen is a heavy, viscous crude oil, having relatively high sulfur content. When properly separated from the oil sands, bitumen may be processed to synthetic crude oil suitable for use as a feedstock for the production of liquid motor fuels, heating oil, and petrochemicals. Oil sand fields exist throughout most of the world. Particularly significant deposits exist in Canada, including the Athabasca oil sands in Alberta, the United States, including the Utah oil sands, South America, including the Orinoco oil sands in Venezuela, and Africa, including the Nigerian oil sands. A majority of all of the known oil in the world is contained in oil sands.[0003]Bitumen can be derived from a slurry containing tar sands using high shear mixing equipment. T...

AI Technical Summary

Benefits of technology

[0006]Embodiments of the present invention advantageously provide a method of extracting bitumen from tar sands that has an extended usable lifetime. An embodiment of the invention includes a method of extracting bitumen from tar sands, the method comprising providing an apparatus for mixing fluids, the apparatus comprising: a housing defining a substantially cylindrical interior chamber bounded by spaced substantially planar side walls joined by a cylindrical peripheral wall; a substantially cylindrical rotor rotatably mounted within the interior chamber, the rotor having an axis, spaced substantially planar sides, and a cylindrical peripheral surface joining the planar sides; the cylindrical peripheral surface of the rotor and the cylindrical peripheral wall of the chamber defining an annular space therebetween having a substantially uniform dimension in the axial direction of the rotor; at least two arrays of spaced bores formed in the peripheral surface of the rotor, each bore of each array extending radially into the rotor a predetermined distance and opening into the annular space, the each array of spaced bores being arranged in a row that extends around the cylindrical peripheral surface of the rotor and being spaced from other arrays such that a void zone therebetween is created where no bores are formed in the peripheral surface of the rotor; at least one fluid inlet in the housing positioned to introduce fluid into the chamber at predetermined locations adjacent one of the substantially planar sides of the rotor; multiple inlets being substantially aligned to equalize pressure on the rotor as fluid is introduced into the chamber through the fluid inlets; and a fluid outlet in the housing positioned for withdrawal of fluid from the chamber at a third predetermined location adjacent the cylindrical peripheral surface of the rotor, the third predetermined location being aligned within the void zone for withdrawal of fluid after it has passed a row of bores and to minimize cavitation damage at the location of the fluid outlet; and providing a separation composition comprising: a wetting agent in the amount of from about 0.001% to about 2.5% by weight of the separating composition; a hydrotropic agent; and a dispersant having flocculating characteristics, wherein the separating composition has a pH of greater than 7.5.

[0007]Another embodiment of the invention includes an apparatus for extracting bitumen from tar sands, the apparatus including: a housing defining a substantially cylindrical interior chamber bounded by spaced substantially planar side walls joined by a cylindrical peripheral wall; a substantially cylindrical rotor rotatably mounted within the interior chamber, the rotor having an axis, spaced substantially planar sides, and a cylindrical peripheral surface joining the planar sides; the cylindrical peripheral surface of the rotor and the cylindrical peripheral wall of the chamber defining an annular space therebetween having a substantially uniform dimension in the axial direction of the rotor; a first array of spaced bores formed in the peripheral surface of the rotor, each bore of the first array extending radially into the rotor a predetermined distance and opening into the annular space, the first array of spaced bores being arranged in a first row that extends around the cylindrical peripheral surface of the rotor; a second array of spaced bores formed in the peripheral surface of the rotor, each bore of the second array extending radially into the rotor a predetermined distance and opening into the annular space, the second array of spaced bores being arranged in a second row that extends around the cylindrical peripheral surface of the rotor, the first and second rows of bores being spaced apart in the axial direction of the rotor and defining a void zone therebetween such that no bores are formed in the peripheral surface of the rotor; a first fluid inlet in the housing positioned to introduce fluid into the chamber at a first predetermined location adjacent one of the substantially planar sides of the rotor; a second fluid inlet in the housing positioned to introduce fluid into the chamber at a second predetermined location adjacent the other one of the substantially planar sides of the rotor, the second fluid inlet being substantially axially aligned with the first fluid inlet to equalize pressure on the rotor as fluid is introduced into the chamber through the fluid inlets; and a fluid outlet in the housing positioned for withdrawal of fluid from the chamber at a third predetermined location adjacent the cylindrical peripheral surface of the rotor, the third predetermined location being aligned within the void zone for withdrawal of fluid after it has passed a row of bores and to minimize cavitation damage at the location of the fluid outlet, wherein the apparatus is configured to receive a separation composition comprising: a wetting agent in the amount of from about 0.001% to about 2.5% by weight of the separating composition; a hydrotropic agent; and a dispersant having flocculating characteristics, wherein the separating composition has a pH of greater than 7.5.

Problems solved by technology

The tar sands are highly abrasive on the machinery used to separate the bitumen from the sand and water.

Conventional mixing equipment is subject to high wear rates that result from high speed operation on the abrasive tar sand slurry.

Slower speed equipment is less effective at bitumen derivation.

Naturally, this requires frequent downtime for the machinery, which means the equipment is rendered unusable and valuable work time is lost due to frequent repairs.

Using less abrasion-prone materials, such as ceramics, for the impellers has been proposed in the past, but has not adequately relieved the problem of extending the usable life of the mixing equipment.

Images