Ammonia synthesis using lithium ion conductive membrane

摘要

Ammonia is synthesized using electrochemical and non-electrochemical reactions. The electrochemical reactions occur in an electrolytic cell having a lithium ion conductive membrane that divides the electrochemical cell into an anolyte compartment and a catholyte compartment. The catholyte compartment includes a porous cathode closely associated with the lithium ion conductive membrane. The overall electrochemical reaction is: 6LiOH+N2→Li3N (s)+3H2O+3/2O2. The nitrogen may be produced by a nitrogen generator. The non-electrochemical reaction involves reacting lithium nitride with water and/or steam as follows: Li3N (s)+3H2O→3LiOH+NH3 (g). The ammonia is vented and collected. The lithium hydroxide is preferably recycled and introduced into the anolyte compartment. The electrolytic cell is shut down prior to reacting the lithium nitride with water. The cathode is preferably dried prior to start up of the electrolytic cell and electrolyzing Li+ and N2 at the cathode.

主权项

1. A process for synthesizing ammonia, comprising:
providing an electrolytic cell comprising a lithium ion conducting membrane configured to selectively transport lithium ions, the membrane positioned between an anolyte compartment configured with an anode and a catholyte compartment configured with a cathode; introducing aqueous LiOH into the anolyte compartment; introducing N2 into the catholyte compartment; and electrolyzing the aqueous LiOH at the anode according to the following oxidation reaction:
6LiOH→6Li++3H2O+3/2O2+6e− electrolyzing Li+ and N2 at the cathode according to the following reduction reaction:
6Li++N2+6e−→Li3N(s) reacting the Li3N with H2O according to the following reaction:
Li3N(s)+3H2O→3LiOH+NH3(g) recovering the NH3; and recovering the LiOH.