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US 2012/0267306 A1Published application
Osmotic separation systems and methods
AssigneeOasys Water, Inc.
InventorsRobert L. McGinnis, Joseph E. Zuback
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Abstract
Separation processes using engineered osmosis are disclosed generally involving the extraction of solvent from a first solution to concentrate solute by using a second concentrated solution to draw the solvent from the first solution across a semi-permeable membrane. Enhanced efficiency may result from using low grade waste heat from industrial or commercial sources.
Claims16
A system for osmotic extraction of a solvent from a first solution, comprising:
- a first chamber having an inlet fluidly connected to a source of the first solution;
- a second chamber having an inlet fluidly connected to a source of a concentrated draw solution comprising ammonia and carbon dioxide in a desired molar ratio of at least one to one;
- a semi-permeable membrane system separating the first chamber from the second chamber;
- a separation system fluidly connected downstream of the second chamber, the separation system configured to receive a dilute draw solution from the second chamber and to recover draw solutes and a solvent stream;
- a recycle system comprising an absorber configured to facilitate reintroduction of the draw solutes to the second chamber to maintain the desired molar ratio;
- and
- a source of low grade heat in thermal communication with the separation system.
4 more elements
2-4. (canceled)
The system of claim 18, wherein the distillation column is positioned below ground level.
A forward osmosis separation process, comprising:
- introducing a first solution on a first side of a semi-permeable membrane;
- introducing a concentrated draw solution comprising ammonia and carbon dioxide at a molar ratio of at least one to one on a second side of the semi-permeable membrane to maintain a desired osmotic concentration gradient across the semi-permeable membrane;
- promoting flow of at least a portion of the first solution across the semi-permeable membrane to form a second solution on the first side of the semi-permeable membrane and a dilute draw solution on the second side of the semi-permeable membrane;
- introducing at least a portion of the dilute draw solution to a separation operation to recover draw solutes and a solvent stream;
- reintroducing the draw solutes to the second side of the semi-permeable membrane to maintain the desired molar ratio of ammonia to carbon dioxide in the concentrated draw solution;
- collecting the solvent stream;
- and
- controlling biological fouling of the semi-permeable membrane.
5 more elements
Dependencies are inferred from the claim text.