METHOD FOR THE DESALINATION OF SUPERSATURATED HOT WATER

Abstract

A method for desalination of hot supersaturated water having a temperature of between 40° C. and 80°, includes contacting the hot water with a reverse osmosis membrane which is resistant to temperatures of between 40 and 80° C. without a prior cooling step.

Claims

1. Method for desalination of hot supersaturated water having a temperature of between 40° C. and 80° C., comprising contacting said hot water with a reverse osmosis membrane which is resistant to temperatures of between 40 and 80° C. without a prior cooling step.

2. Method according to claim 1, further comprising a step of cooling of the desalinated permeate from the reverse osmosis.

3. Method according to claim 1, further comprising, prior to the contacting of the hot water with the reverse osmosis membrane, a step of removing suspended matter or a step of adding a sequestrant, or both.

4. Method according to claim 1, wherein the hot water is pressurized before being contacted with the reverse osmosis membrane.

5. Method according to claim 1, wherein the hot supersaturated water comprises compounds selected from calcium, magnesium, sodium, potassium, carbonates, bicarbonates, chlorides, sulfates or a mixture thereof.

6. Method according to claim 5, wherein the hot supersaturated water comprises compounds selected from calcium, magnesium, sodium, potassium, carbonates, bicarbonates, chlorides, sulfates or a mixture thereof, with a total amount of at least 500 mg/l.

7. Method according to claim 1, wherein the hot supersaturated water further comprises compounds selected from iron, manganese, silica, sulfur or a mixture thereof.

8. Method according to claim 2, wherein the permeate is cooled to a temperature at least less than 45° C. and preferably less than 40° C.

9. Method according to claim 1, wherein the hot supersaturated water comprises radionuclides.

10. Method according to claim 1, wherein the permeate of said hot water is cooled following its osmosis membrane traversal.

11. Method according to claim 2, further comprising, prior to the contacting of the hot water with the reverse osmosis membrane, a step of removing suspended matter or a step of adding a sequestrant, or both.

12. Method according to claim 2, wherein the hot water is pressurized before being contacted with the reverse osmosis membrane.

13. Method according to claim 3, wherein the hot water is pressurized before being contacted with the reverse osmosis membrane.

14. Method according to claim 2, wherein the hot supersaturated water comprises compounds selected from calcium, magnesium, sodium, potassium, carbonates, bicarbonates, chlorides, sulfates or a mixture thereof.

15. Method according to claim 3, wherein the hot supersaturated water comprises compounds selected from calcium, magnesium, sodium, potassium, carbonates, bicarbonates, chlorides, sulfates or a mixture thereof.

16. Method according to claim 4, wherein the hot supersaturated water comprises compounds selected from calcium, magnesium, sodium, potassium, carbonates, bicarbonates, chlorides, sulfates or a mixture thereof.

17. Method according to claim 2, wherein the hot supersaturated water further comprises compounds selected from iron, manganese, silica, sulfur or a mixture thereof.

18. Method according to claim 3, wherein the hot supersaturated water further comprises compounds selected from iron, manganese, silica, sulfur or a mixture thereof.

19. Method according to claim 4, wherein the hot supersaturated water further comprises compounds selected from iron, manganese, silica, sulfur or a mixture thereof.

20. Method according to claim 5, wherein the hot supersaturated water further comprises compounds selected from iron, manganese, silica, sulfur or a mixture thereof.

Description

[0062] For further illustration of the method of the present invention, a description of one embodiment is given below. It remains the case, of course, that this is only one example, without any limitative character at all. In the course of this description, reference is made to FIG. 1 of the attached drawings, which is a scheme illustrating the various steps of the method according to the invention.

[0063] The raw water drawn from the well (1) is immediately directed towards the reverse osmosis system (2), by means of a pump (not shown in the figure), without breach of head, in order to prevent loss of CO2. The latter passes almost entirely through the membrane towards the permeate (product water side). Upstream of the reverse osmosis system, a manometer (M) measures the exit pressure of the raw water exiting the well. The permeate is then cooled to the desired temperature and taken to a storage tank (3), then transported to the site of use.

[0064] The method according to the invention finds its primary application in the treatment of deep natural water which is hot and exhibits a calcium carbonate supersaturation potential.

[0065] This method however may be applied for production: [0066] of water intended for human consumption, [0067] of water intended for supplying industrial processes, such as washing water, water involved in the production of the manufactured product, water intended for feeding boilers, etc., and [0068] of water intended for irrigation.

[0069] Finally, this method may also be applied to the treatment of water resulting from an industrial manufacturing process which would bring a calcium carbonate supersaturation potential in a water of more than 40-45° C., if the aim is to recycle the water, recover components from it, or treat it prior to discharge.

[0070] Relative to the method used to date and as described above, the method according to the invention accumulates a number of advantages: [0071] removal of the risk of precipitation in all the steps, [0072] smaller-sized cooling tower for a given production rate, since only the production permeate is processed (the brine discharge can certainly be evacuated in hot form), [0073] smaller-sized cooling tower owing to the reduced cooling required, linked only to the temperature required at the exit from the plant, [0074] no risk of clogging of the cooling tower, and hence maximum availability and limited maintenance costs, [0075] a filtration step upstream of the reverse osmosis is pointless, since there is no longer any suspended matter to be removed, making for a marked reduction in capital and operating costs. The step could simply be retained if suspended matter was suspected in the raw water obtained directly from drilling, [0076] no chemical removal of bicarbonates (by dosing of acid) and no need to reduce the precipitation risk in the cooling tower and during the filtration step (by application of a sequestrant), making for marked economic savings in operation.