Water desalination process and apparatus
First Claim
1. A process for treating a water stream comprising:
- feeding a water stream through a desalination process to produce a byproduct stream, the byproduct stream containing dissolved calcium ions and sulfate ions;
contacting the byproduct stream with a cation-removal device and an anion-removal device to remove a substantial portion of the calcium ions and the sulfate ions, the calcium ions passing into a first salt stream, the sulfate ions passing into a second salt stream, the first salt stream containing chlorine ions, the second salt stream containing sodium ions;
separately feeding the first salt stream and the second salt stream to a calcium sulfate precipitation chamber for precipitating calcium sulfate; and
collecting the precipitated calcium sulfate.
1 Assignment
0 Petitions
Accused Products
Abstract
A process and system for purifying water is disclosed. For example, in one embodiment, the process may be used to remove a divalent salt, such as calcium sulfate, from a water source in order to prevent the divalent salt from precipitating during the process. The water source, for instance, may be fed to an ion separating device, such as an electrodialysis device. In the electrodialysis device, an ion exchange takes place between the divalent salt and another salt, such as a monovalent salt to produce two concentrated salt streams that contain salts having greater solubility in water than the divalent salt. In one embodiment, the two salt streams that are produced may then be combined to precipitate the divalent salt in a controlled manner. During the process, various other components contained within the water feed stream may also be removed from the stream and converted into useful products. In one particular embodiment, the process is configured to receive a byproduct stream from a reverse osmosis process.
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Citations
72 Claims
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1. A process for treating a water stream comprising:
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feeding a water stream through a desalination process to produce a byproduct stream, the byproduct stream containing dissolved calcium ions and sulfate ions; contacting the byproduct stream with a cation-removal device and an anion-removal device to remove a substantial portion of the calcium ions and the sulfate ions, the calcium ions passing into a first salt stream, the sulfate ions passing into a second salt stream, the first salt stream containing chlorine ions, the second salt stream containing sodium ions; separately feeding the first salt stream and the second salt stream to a calcium sulfate precipitation chamber for precipitating calcium sulfate; and collecting the precipitated calcium sulfate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 67, 68)
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28. A process for purifying water by removing a low soluble salt, MY, from a water stream to prevent the low soluble salt from precipitating within the water stream, the process comprising:
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feeding a salt solution containing a dissolved salt, NX, to an ion-removal device for forming a first salt stream containing an anion, X, and a second salt stream containing a cation, N; feeding the water stream containing the low soluble salt, MY, to an ion-removal device for adding the cation, M, to the first salt stream and for adding the anion, Y, to the second salt stream, the low soluble salt, MY, comprising a divalent salt; and wherein N comprises Li+, Na+, K+, Cs+, Rb+, NH4+ or an amine, and wherein X comprises Cl−
, Br−
, I−
, NO3−
or an organic ion, and wherein both salts NY and MX are more soluble in water than the salts MY. - View Dependent Claims (29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 69, 70)
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50. A process for purifying water by removing a low soluble salt, MY, from a water stream to prevent the low soluble salt from precipitating within the water stream, the process comprising;
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feeding the water stream containing the low soluble salt, MY, to an ion-removal device for adding the cation, M, to a first salt stream and for adding the anion, Y, to a second salt stream, the low soluble salt, MY, comprising a divalent salt; feeding a salt solution containing a dissolved salt, NX, to the ion-removal device for adding the anion, X, to the first salt stream and for adding the cation, N, to the second salt stream, the salt solution being derived from the water stream containing the low soluble salt; and wherein N comprises Li+, Na+, K+, Cs+, Rb+, NH4+ or an amine, and wherein X comprises Cl−
, Br−
, I−
, NO3−
or an organic ion, and wherein both salts NY and MX are more soluble in water than the salt MY. - View Dependent Claims (51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 71, 72)
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Specification