Back to results
US 8,999,171 B2Granted
Membrane and electrodialysis based seawater desalination with salt, boron and gypsum recovery
AssigneeHL Seawater Holdings, LLC
InventorPaul Steven Wallace
Life of this patent
Estimating the term…
Abstract
A method of producing desalinated water and recovering minerals from the feedwater uses membrane separation and electrodialysis brine concentration. This process can recover all of the minerals as high purity industrial minerals, including capturing the calcium and sulfate as agricultural grade gypsum and boron as high purity boric acid. In addition the process allows the use of low cost lime or dolime to produce valuable magnesium hydroxide.
Claims23
A method for salvaging minerals from seawater comprising:
- preheating the seawater;
- supplying the preheated seawater to an air stripper configured to reduce an amount of carbon dioxide in the preheated seawater;
- directing the preheated seawater from the air stripper through a nano filtration unit configured to separate the preheated seawater into a non-permeate stream and a permeate stream;
- capturing one or more first minerals from the non-permeate stream using a first stage mineral recovery unit, wherein the first stage mineral recovery unit is fluidly coupled to the nano filtration unit and capturing the one or more first minerals comprises adding lime to the first stage mineral recovery unit such that at least one of the one or more first minerals captured is magnesium hydroxide;
- providing a second stage mineral recovery unit disposed downstream from the nano filtration unit with the permeate stream, wherein the second stage mineral recovery unit comprises an electrodialysis unit configured to generate a concentrate;
- and
- capturing one or more second minerals from the concentrate.
4 more elements
A method for salvaging minerals from seawater comprising:
- preheating the seawater;
- supplying the preheated seawater to an air stripper configured to reduce an amount of carbon dioxide in the preheated seawater;
- directing the preheated seawater from the air stripper through a nano filtration unit configured to separate the preheated seawater into a first non-permeate stream and a first permeate stream;
- flowing the first permeate stream through a seawater reverse osmosis system fluidly coupled to the nano filtration unit, wherein the seawater reverse osmosis system is configured to generate a second non-permeate stream and a second permeate stream;
- processing the first non-permeate stream within a first stage mineral recovery unit fluidly coupled to the nano filtration unit, wherein the first stage mineral recovery unit is configured to capture one or more first minerals from the first non-permeate stream, and wherein capturing the one or more first minerals comprises adding lime to the first stage mineral recovery unit such that at least one of the one or more first minerals captured is high purity magnesium hydroxide;
- providing a second stage recovery unit disposed downstream from the seawater reverse osmosis system with the second non-permeate stream, wherein the second stage mineral recovery unit comprises an electrodialysis unit;
- and
- capturing one or more second minerals from the second permeate stream.
5 more elements
Dependencies are inferred from the claim text.