Process to separate an aqueous feed
AssigneeMezt B.V.
InventorsAdriaan Hendrik LIEFTINCK, Edward Kenneth SIBEIJN, Niels VAN LINDEN
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Abstract
The invention is directed to a process for separating an aqueous feed comprising of dissolved ammonium bicarbonate. The process comprises: a step (a) in which an electrodialysis is performed to obtain a diluate and a concentrate comprising of ammonium bicarbonate and a step (b) in which the total ammonia nitrogen (TAN) as present in the concentrate is separated from the bicarbonate ions as present in the concentrate by means of a bipolar membrane electrodialysis to a total ammonia nitrogen (TAN) alkaline fraction and a bicarbonate acid fraction.
Claims24
A process for separating an aqueous feed comprising of dissolved ammonium bicarbonate by
- (a) performing an electrodialysis in an electrodialysis unit wherein ions are transported via a membrane from the aqueous feed under influence of a positive and negative electrode to a mineral poor aqueous solution to obtain a concentrate comprising of ammonium bicarbonate and wherein the remaining aqueous feed is obtained as a diluate, wherein the electrodialysis unit does not comprise a bipolar membrane,
- (b) separating the total ammonia nitrogen (TAN) as present in the concentrate from the bicarbonate ions as present in the concentrate by means of a bipolar membrane electrodialysis as performed in a bipolar membrane electrodialysis system to a total ammonia nitrogen (TAN) alkaline fraction and a bicarbonate acid fraction,
- wherein in step (b) the bipolar membrane electrodialysis system is of a three chamber type with bipolar membranes (BPM), an anion exchange membranes (AEM) and a cation exchange membranes (CEM), wherein the bicarbonate ions pass the anion exchange membrane to become the bicarbonate acid fraction, wherein the ammonium ions of the total ammonia nitrogen (TAN) pass the cation exchange membrane to become the total ammonia nitrogen (TAN) alkaline fraction and wherein the remaining concentrate is obtained as a third remaining aqueous fraction, which third remaining aqueous fraction is recycled to the electrodialysis of step (a) to be used as the mineral poor aqueous solution where it picks up the ammonium bicarbonate to become the concentrate or
- wherein in step (b) the bipolar membrane electrodialysis system is of a two chamber type with bipolar membranes (BPM) and cation exchange membranes (CEM), wherein the ammonium ions of the total ammonia nitrogen (TAN) pass the cation exchange membrane to become the total ammonia nitrogen (TAN) alkaline fraction and wherein the remaining concentrate becomes the bicarbonate acid fraction,
- wherein part of the bicarbonate in the bicarbonate acid fraction is separated as carbon dioxide to obtain an aqueous fraction poor in bicarbonate which aqueous fraction poor in bicarbonate is recycled to the electrodialysis of step (a) to be used as the mineral poor aqueous solution where it picks up the ammonium bicarbonate to become the concentrate.
(canceled)
(canceled)
A process configuration comprising an electrodialysis unit, a bipolar membrane electrodialysis unit and a membrane stripping unit,
- wherein the electrodialysis unit has an outlet for a concentrate which is fluidly connected to the bipolar membrane electrodialysis unit and wherein the electrodialysis unit does not comprise a bipolar membrane,
- wherein the bipolar membrane electrodialysis unit is of a three chamber type with bipolar membranes (BPM), an anion exchange membranes (AEM) and a cation exchange membranes (CEM), or
- wherein the bipolar membrane electrodialysis system is of a two chamber type with bipolar membranes (BPM) and cation exchange membranes (CEM), and
- wherein the bipolar membrane electrodialysis unit has an outlet for a total ammonia nitrogen (TAN) alkaline fraction.
(canceled)
Dependencies are inferred from the claim text.