Method for increasing evaporation rate of an evaporative pond

Patent metadata

Field	Value
Publication number	US-10150677-B2
Application number	US-201314132149-A
Country	US
Kind code	B2
Filing date	Dec 18, 2013
Priority date	Dec 20, 2012
Publication date	Dec 11, 2018
Grant date	Dec 11, 2018

Abstract

A method for increasing the evaporation rate of an evaporative pond containing pond liquor comprising water and at least 1% by weight of sodium carbonate, said evaporative pond being in contact with an ambient air at an ambient air temperature of more than 0° C., the method comprising the following steps: feeding part of the pond liquor to a heat exchanger; heating the pond liquor in the heat exchanger with heat and producing a heated pond liquor; feeding the heated pond liquor into a spraying device at an operating temperature of at least 10° C. above the ambient air temperature; and spraying the heated pond liquor into an open area of the evaporative pond with the spraying device, so as to evaporate at least part of the water of the pond liquor when sprayed.

First claim

The invention claimed is:

1. A method for increasing the evaporation rate of an evaporative pond containing pond liquor comprising water and at least 1% by weight of sodium carbonate, said evaporative pond being in contact with an ambient air at an ambient air temperature of more than 0° C., wherein said pond liquor further contains at least 2% by weight of sodium chloride, or of sodium sulfate, or of both sodium chloride and sodium sulfate, said method comprising the following steps:
feeding part of said pond liquor to a heat exchanger;
heating said pond liquor in said heat exchanger with heat and producing a heated pond liquor;
feeding said heated pond liquor into a spraying device at an operating temperature of at least 10° C. above the ambient air temperature; and
spraying said heated pond liquor into an open area of said evaporative pond with said spraying device, so as to evaporate at least part of the water of said pond liquor when sprayed, wherein water, or steam condensate, or steam condensate at a temperature of at least 35° C., is sequentially fed to said spraying device in replacement of at least part of said heated pond liquor at least 1 minute per period of 8 hours.

2. The method according to claim 1 wherein said pond liquor comprises at most 30% by weight of sodium carbonate.

3. The method according to claim 1 wherein said pond liquor comprises at most 4% by weight of sodium bicarbonate.

4. The method according to claim 3 wherein said pond liquor comprises at most 18% sodium carbonate and at most 3% sodium bicarbonate.

5. The method according to claim 1 wherein the ambient air temperature is at least 15° C.

6. The method according to claim 1 wherein said operating temperature is at least 30° C.

7. The method according to claim 1 wherein said spraying device is selected from the group consisting of irrigation sprinkler device, rotating sprinkler device, hose reel raingun sprinklers system, centre pivot sprinklers system, spray nozzles, spray nozzles arrays, turbomist device, and combinations thereof.

8. The method according to claim 1 wherein said heat is selected from the group consisting of hot steam condensate, low pressure steam of less than 3.5 bars, and combination thereof.

9. The method according to claim 8 wherein said hot steam condensate or low pressure steam of less than 3.5 bar after providing heat to said heat exchanger is transformed into a cooled condensate, and wherein said cooled condensate is further used to recover heat from fumes of a steam generator.

10. The method according to claim 1 wherein said heat is generated by a gas fired heater fuelled by methane recovered from a longwall gob vent.

11. The method according to claim 1 wherein said water or said steam condensate, or said steam condensate at a temperature of at least 35° C., is sequentially fed to said spraying device in replacement of at least part of said heated pond liquor at least 1 minute per period of 2 hours.

12. The method according to claim 1 , wherein said method further comprises purging part of said pond liquor into a subsequent pond to control the sodium chloride or the sodium sulfate concentration in said pond liquor.

13. The method according to claim 1 wherein said evaporative pond is fed with a sodium carbonate aqueous stream for recovering partly or totally the sodium carbonate from said sodium carbonate aqueous stream.

14. The method according to claim 13 wherein said sodium carbonate aqueous stream comprises an aqueous purge from a sodium carbonate crystallizer or from a sodium carbonate derivative crystallizer, and comprises at least 6% and at most 30% by weight of sodium carbonate.

15. The method according to claim 13 wherein said sodium carbonate aqueous stream is generated in a first pond, and wherein a sodium carbonate aqueous effluent comprising or consisting of a sodium carbonate aqueous purge from a sodium carbonate crystallizer or from a sodium carbonate derivative crystallizer, is fed to said first-pond, said sodium carbonate aqueous effluent is cooled down so as to generate:
sodium carbonate decahydrate crystals, and said sodium carbonate aqueous stream.

16. The method according to claim 1 further comprising the steps of:
stopping the feeding of said part of said pond liquor to said heat exchanger and to said spraying device before reaching a saturated pond liquor in sodium salts at the ambient air temperature,
allowing the water of said pond liquor to further evaporate by further exposing said pond liquor to ambient air conditions, in the same evaporative pond or in a further evaporative crystallization pond area so as to crystallize further sodium salts comprising sodium chloride or sodium sulfate.

17. The method according claim 1 further comprising the steps of:
stopping said feeding of the part of said pond liquor to said heat exchanger and to said spraying device before reaching a saturated pond liquor in sodium salts at the ambient air temperature,
feeding said pond liquor to a solution mining cavity or a mined out cavity or in a deep well injection.

18. A process for manufacturing sodium carbonate or a sodium carbonate derivative comprising the method according to claim 1 .

19. A method for increasing the evaporation rate of an evaporative pond containing pond liquor comprising water and at least 1% by weight of sodium carbonate, said evaporative pond being in contact with an ambient air at an ambient air temperature of more than 0° C. and lower than 35° C. wherein said pond liquor further contains at least 2% by weight of sodium chloride, or of sodium sulfate, or of both sodium chloride and sodium sulfate, said method comprising the following steps:
feeding part of said pond liquor to a heat exchanger;
heating said pond liquor in said heat exchanger with heat and producing a heated pond liquor;
feeding said heated pond liquor into a spraying device at an operating temperature of at least 10° C. above the ambient air temperature; and
spraying said heated pond liquor into an open area of said evaporative pond with said spraying device, so as to evaporate at least part of the water of said pond liquor when sprayed, wherein said heated pond liquor is sequentially over-heated during a period of time from 5 to 10 minutes every one or two hours at a sequential temperature before being sprayed by said spraying device, and wherein said sequential temperature is at least 5° C. above said operating temperature.

20. The method according to claim 19 wherein said pond liquor comprises at most 4% by weight of sodium bicarbonate.

21. The method according to claim 19 wherein said spraying device is selected from the group consisting of irrigation sprinkler device, rotating sprinkler device, hose reel raingun sprinklers system, centre pivot sprinklers system, spray nozzles, spray nozzles arrays, turbomist device, and combinations thereof.

Assignees

• Solvay

Inventors

• Vandendoren Alain
• Mote Jessica A

Classifications

• B01D1/18

  to obtain dry solids (B01D1/24 takes precedence) · CPC title

• C02F2103/10

  from quarries or from mining activities · CPC title

• B01D1/20

  Sprayers (in general B05B) · CPC title

• C01D7/24

  Crystallisation · CPC title

• C01D5/18

  Dehydration {(C01D5/145 takes precedence)} · CPC title