Water recovery system SAGD system utilizing a flash drum

1. A water recovery process for SAGD (Steam Assisted Gravity Drainage) system for a heavy oil recovery facility, the process comprising:

providing a flash drum and a flash drum heat exchanger/condenser;

separating oil from water;

receiving in the flash drum hot water produced after the step of separating oil from water, the hot water being at a temperature above the water atmospheric boiling point;

cooling the hot water in the flash drum and the flash drum heat exchanger to a temperature below the water atmospheric boiling point; and

transferring the cooled water to a remaining section of the water recovery process.

2. The water recovery process of claim 1 , wherein the hot water produced contains impurities, such as traces of oil, the water recovery process further comprising providing a final water treating unit; and

removing at least some of said impurities from the water with the final water treating unit.

3. The water recovery process of claim 2 wherein the final water treating unit comprises at least one of an induced gas flotation unit and oil removal filters.

4. A water recovery process comprising:

providing a flash drum, a flash drum heat exchanger/condenser and a final water treating unit;

introducing a hot water produced after a separation of oil from water into the flash drum;

separating the hot water produced into a cooled liquid and a vapour;

cooling the vapour in the flash drum heat exchanger/condenser;

mixing the condensed liquids from the heat exchanger with the cooled liquid, from the flash drum heat exchanger/condenser forming a mixture;

transferring this mixture into the final water treating unit,

removing impurities from the water;

producing a cleaned water;

transferring the cleaned water to a remainder of the water recovery process or to atmospheric tanks for storage.

5. The water recovery process of claim 1 or 4 wherein the flash drum operates below the atmospheric pressure to prevent flashing in the down stream equipment.

6. The water recovery process of claim 1 or 4 wherein the operating pressure of the flash drum is between (+10) kPag to (−10) kPag.

7. The water recovery process of claim 1 or 4 wherein the flash drum heat exchanger/condenser receives the water vapour from the flash drum and chills that vapour, to produce a chilled vapour and liquid stream to a temperature below the water atmospheric boiling point in a range of (40)° C. to (100)° C.

8. The water recovery process of claim 1 or 4 wherein the flash drum heat exchanger/condenser receives the water vapour from the flash drum and the final water treating unit, and chills that vapour, to produce a chilled vapour and liquid stream to a temperature below the water atmospheric boiling point in a range of (40)° C. to (100)° C.

9. The water recovery process of claim 1 or 4 wherein the hot water temperature is between (100)° C. and (180)° C. with a pressure between (0) kPag and (1400) kPag.

10. The water recovery process of claim 1 or 4 wherein the water exiting the flash drum is at its bubble point temperature at a pressure between (−17) kPag and (0) kPag, and the vapour is at its bubble point temperature at a pressure between (−17) kPag and (0) kPag.

11. The water recovery process of claim 1 or 4 wherein the water exiting the flash drum heat exchanger/condenser is at a temperature between (40)° C. and (100)° C.

12. The water recovery process of claim 4 wherein the combined water entering the final water treating unit is at a temperature between (90)° C. and (100)° C.

13. The water recovery process of claim 4 wherein the water exiting the final water treatment unit is at a temperature of between (90)° C. and (100)° C.

14. The water recovery process of claim 4 wherein the flash drum heat exchanger/condenser and the flash drum are physically located above the final water treating unit to provide a pump suction head.

15. The water recovery process of claim 4 wherein the final water treating unit includes a gas floatation unit, and wherein a pump suction head is between (2) m and (6) m water for the gas floatation unit.

16. The water recovery process of claim 1 or 4 wherein the flash drum heat exchanger/condenser is cooled by glycol.

17. The water recovery process of claim 1 or 4 wherein cold make-up water is directed to the flash drum and further including preheating the water and reducing the amount of coolant in the flash drum heat exchanger/condenser.

18. The water recovery process of claim 1 or 4 , wherein the process is conducted with a system that is transportable and modular and is suitable for crude oil recovery from oil sands.