Simplified Architecture for Desalination via Electrodialysis

An electrodialysis desalination device, comprising:

• a first electrode including a first-stage side;
• a second electrode including a first-stage side;
• a first stage between the first-stage side of the first electrode and the first-stage side of the second electrode, the first stage including at least one first-stage cell pair positioned between the first-stage side of the first electrode and the first-stage side of the second electrode, each cell pair including a pair of first-stage selectively permeable ion-exchange membranes with alternating selectivity that define first-stage channels on opposite sides of each first-stage membrane for respective flows of a first-stage diluate stream and a first-stage concentrate stream between the first electrode and the second electrode, wherein each of the channels includes an inlet and an outlet;
• a second stage including at least one second-stage cell pair including a plurality of second-stage selectively permeable ion-exchange membranes with alternating selectivity that define second-stage channels on opposite sides of each second-stage membrane for respective flows of a second-stage diluate stream and a second-stage concentrate stream, wherein the outlet for the first-stage channel through which the first-stage diluate stream flows is in fluid communication with the inlet of the second-stage channel through which the second-stage diluate stream flows, and wherein the outlet for the first-stage channel through which the first-stage concentrate stream flows is in fluid communication with the inlet of the second-stage channel through which the second-stage concentrate stream flows;
• and
• a single pump configured to pump the diluate streams and the concentrate streams through the first stage and through the second stage.

An electrodialysis desalination device, comprising:

• a first electrode including a first-stage side;
• a second electrode including a first-stage side;
• a first stage between the first-stage side of the first electrode and the first-stage side of the second electrode, the first stage including at least one first-stage cell pair positioned between the first-stage side of the first electrode and the first-stage side of the second electrode, each cell pair including a pair of first-stage selectively permeable ion-exchange membranes with alternating selectivity that define first-stage channels on opposite sides of each first-stage membrane for respective flows of a first-stage diluate stream and a first-stage concentrate stream between the first electrode and the second electrode, wherein each of the channels includes an inlet and an outlet;
• and
• a single pump configured to pump the diluate streams and the concentrate streams through the first stage,
• wherein the pump and the channels are configured to generate a flow rate of the diluate stream that is independent and distinct from a flow rate of the concentrate stream through the channels.

A method for continuous electrodialysis desalination using a continuous electrodialysis desalination device, the device comprising:

• a first electrode including a first-stage side;
• a second electrode including a first-stage side;
• a first stage between the first-stage side of the first electrode and first-stage side of the second electrode, the first stage including at least one first-stage cell pair positioned between the first-stage side of the first electrode and the first-stage side of the second electrode, each cell pair including a pair of first-stage selectively permeable ion-exchange membranes with alternating selectivity that define first-stage channels on opposite sides of each first-stage membrane for respective flows of a first-stage diluate stream and a first-stage concentrate stream between the first electrode and the second electrode, wherein each of the first-stage channels includes an inlet and an outlet;
• a second stage including at least one second-stage cell pair including a pair of second-stage selectively permeable ion-exchange membranes with alternating selectivity that define second-stage channels for the diluate stream and for the concentrate stream on opposite sides of each second-stage membrane, wherein each of the second-stage channels includes an inlet and an outlet;
• and
• a single pump configured to pump the diluate streams and the concentrate streams through the first stage,
• the method comprising:
• using the single pump to flow an aqueous saline feed stream through inlets of the first-stage channels;
• using a voltage source to apply a first charge to the first and electrode and to apply a second charge to the second electrode, wherein the first charge is opposite the second charge;
• selectively extracting ions through the first-stage membranes, thereby producing the first-stage diluate stream and the first-stage concentrate stream in respective first-stage channels;
• extracting the first-stage diluate stream from the outlet of the first-stage channel for the first-stage diluate stream;
• extracting the first-stage concentrate stream from the outlet of the first-stage channel for the first-stage concentrate stream;
• using the single pump to flow the first-stage diluate stream from the outlet of the first-stage channel for the diluate stream into the inlet of the second-stage channel for the diluate stream;
• using the single pump to flow the first-stage concentrate stream from the outlet of the first-stage channel for the concentrate stream into the inlet of the second-stage channel for the concentrate stream;
• selectively extracting ions through the second-stage membranes, thereby producing the second-stage diluate stream and the second-stage concentrate stream in respective second-stage channels;
• extracting the second-stage diluate stream from the outlet of the second-stage channel for the diluate stream;
• and
• extracting the second-stage concentrate stream from the outlet of the second-stage channel for the concentrate stream.

A method for continuous electrodialysis desalination using a continuous electrodialysis device, the device comprising:

• a first electrode including a first-stage side;
• a second electrode including a first-stage side;
• a first stage between the first-stage side of the first electrode and first-stage side of the second electrode, the first stage including at least one first-stage cell pair positioned between the first-stage side of the first electrode and the first-stage side of the second electrode, each cell pair including a pair of first-stage selectively permeable ion-exchange membranes with alternating selectivity that define first-stage channels on opposite sides of each first-stage membrane for respective flows of a first-stage diluate stream and a first-stage concentrate stream between the first electrode and the second electrode, wherein each of the first-stage channels includes an inlet and an outlet;
• and
• a single pump configured to pump the diluate streams and the concentrate streams through the first stage,
• the method comprising:
• using the single pump to flow an aqueous saline feed stream through inlets of the first-stage channels;
• using a voltage source to apply a first charge to the first and electrode and to apply a second charge to the second electrode, wherein the first charge is opposite the second charge;
• selectively extracting ions through the first-stage membranes, thereby producing the first-stage diluate stream and the first-stage concentrate stream in respective first-stage channels;
• extracting the first-stage diluate stream from the outlet of the first-stage channel for the first-stage diluate stream;
• extracting the first-stage concentrate stream from the outlet of the first-stage channel for the first-stage concentrate stream;
• and
• independently controlling flow of (a) the diluate streams and (b) the concentrate streams to establish a flow rate of the diluate streams that is independent and distinct from a flow rate of the concentrate stream.