FIELD OF THE INVENTION

The present invention generally relates to apparatuses, systems, and methods for separation of a target species from a gas stream via an electrochemical process.

BACKGROUND OF THE INVENTION

Efforts have been made to remove target species from gas mixtures. For example, over the last two decades there has been a constant effort to mitigate global warming by curbing anthropogenic carbon dioxide (CO2) emission. Carbon capture and storage (CCS) is one of the most studied solutions proposed thus far towards this end, and a number of approaches have been pursued to tackle carbon dioxide at different stages of its production: either post combustion capturing at power plants, or concentrating it from the atmosphere, after which it is either pressurized and stored in geological formations, or it is converted to commercially useful chemical compounds. Thus, a number of carbon capturing methods have been devised with varying degrees of success. However, current methods/systems have many disadvantages, including high energy requirements and waste. Furthermore, conventional thermal methods to capture carbon dioxide are failing to meet the ever-stricter efficiency and capacity criteria set by regulatory agencies. Accordingly, improved apparatuses, methods, and/or systems are needed.

SUMMARY OF THE INVENTION

The present disclosure generally relates to apparatuses, systems, and methods for separating a target species (e.g., CO2) from a gas mixture (e.g., gas stream) via an electrochemical process.

In some embodiments, an electrochemical cell is provided. The electrochemical cell may comprise: a first negative electrode and a second negative electrode, each comprising a gas permeable layer and a primary electroactive composite layer; a positive electrode positioned between the first and second negative electrodes and comprising a first complementary electroactive composite layer facing the first negative electrode and a second complementary electroactive composite layer facing the second negative electrode; a first separator positioned between the first negative electrode and the positive electrode; and a second separator positioned between the second negative electrode and the positive electrode, wherein each of the first and second separators is able to be saturated with an ionic liquid.

In some embodiments, a gas separation system is provided. The gas separation system may comprise a plurality of electrochemical cells in fluid communication with a gas inlet and a gas outlet. Each of the plurality of electrochemical cells may comprise: a first porous negative electrode and a second porous negative electrode, each comprising a first electroactive species; a positive electrode comprising a second electroactive species; a first separator positioned between the first porous negative electrode and the positive electrode; and a second separator positioned between the second porous negative electrode and the positive electrode, wherein each of the first and second separators is able to be saturated with an ionic liquid.

In some embodiments a method of treating a gas stream is provided. The method may comprise applying a first potential difference across an electrochemical cell. The electrochemical cell may comprise: at least one porous negative electrode comprising a first electroactive species; a positive electrode comprising a second electroactive species; and a separator saturated with a conductive liquid and positioned between the at least one porous negative electrode and the positive electrode. The method may further comprise introducing a gas stream comprising a target species to the electrochemical cell to bond the target species to the first electroactive species to produce a treated gas stream.

In some embodiments, a method of operating a gas separation system is provided. The gas separation system may comprise a first set of electrochemical cells and a second set of electrochemical cells. The method may comprise introducing a gas stream comprising a target species to the gas separation system. It may further comprise operating the first set of electrochemical cells in a charge mode to bond the target species to a first electroactive species of the first set of electrochemical cells to produce a treated gas stream. It may further comprise simultaneously operating the second set of electrochemical cells in a discharge mode to release the target species from the first electroactive species of the second set of electrochemical cells to produce a target species-rich gas stream. Each electrochemical cell of the first and second set of electrochemical cells may comprise: at least one porous negative electrode comprising a first electroactive species; a positive electrode comprising a second electroactive species; and a separator saturated with an ionic liquid and positioned between the at least one porous negative electrode and the positive electrode.

