System and method for direct steam injection into slurries
AssigneeCanadian Natural Upgrading Limited
InventorsDuane SERATE, Haifeng LIU, Jose ABREU, John AJEDEGBA
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Abstract
A system and method is provided for direct condensing steam heating of oil sands process slurry streams including viscous bitumen froth and tailings products streams. Slurry viscosities greater than that of water increase cavitation and vibration issues. High solids content exacerbate component erosions. Difficult, and competing, steam and slurry interactions are managed by steam nozzle arrangements and management of steam injection at sub-sonic velocities based on a ratio of the slurry back-pressure Pb and steam supply delivery pressure Po.
Claims26
A system for direct steam injection to heat a viscous oil sand process slurry, the slurry comprising hydrocarbons, water and solids and a viscosity at least 5 times that of water or greater, comprising:
- a first slurry conduit having a first bore for conducting the slurry therealong at a first pressure;
- and
- a second steam conduit, having a steam outlet situate within first conduit, for co-injecting superheated steam therefrom and directed downstream into the viscous slurry at a second pressure, a pressure ratio of the first pressure to the second pressure being between 0.55 and about 0.9.
A method for direct steam injection to heat a viscous oil sand process slurry, the slurry comprising hydrocarbons, water and solids and a viscosity at least 5 times that of water or greater, comprising:
- flowing the slurry along a first conduit having an axis;
- injecting steam axially into the slurry from a nozzle at a superheated steam supply pressure and temperature;
- measuring a slurry pressure of the slurry upstream of the steam injection;
- and
- maintaining the velocity of the injected stream from the nozzle to a subsonic to about a sonic velocity.
Dependencies are inferred from the claim text.