Methods for producing ammonia and related systems

Abstract

A method for producing ammonia comprises introducing a first feed stream to a positive electrode of an electrochemical cell. The electrochemical cell comprises the positive electrode, a negative electrode, and an electrolyte between the positive electrode and the negative electrode. A second feed stream comprising a nitrogen source is introduced to the negative electrode and a potential difference is applied between the positive electrode and the negative electrode to produce hydrogen ions, a first product stream comprising carbon monoxide, and a second product stream comprising ammonia. Additional methods and systems are disclosed.

What is claimed is: 
     
         1 . A method for producing ammonia comprising:
 introducing a first feed stream comprising carbon dioxide to a positive electrode of an electrochemical cell, the electrochemical cell comprising the positive electrode, an electrolyte, and a negative electrode;   introducing a second feed stream comprising a nitrogen source to the negative electrode; and   applying a potential difference between the positive electrode and the negative electrode of the electrochemical cell to produce hydrogen ions, a first product stream comprising carbon monoxide, and a second product stream comprising ammonia.   
     
     
         2 . The method of  claim 1 , wherein introducing a first feed stream to a positive electrode comprises introducing the first feed stream comprising the carbon dioxide and one or more alkane. 
     
     
         3 . The method of  claim 2 , wherein introducing a first feed stream to a positive electrode comprises introducing the first feed stream comprising carbon dioxide, methane, and another alkane. 
     
     
         4 . The method of  claim 2 , wherein applying a potential difference between the positive electrode and the negative electrode comprises producing the first product stream substantially free of carbon dioxide and the one or more alkane. 
     
     
         5 . The method of  claim 1 , wherein introducing a first feed stream comprising carbon dioxide to a positive electrode of an electrochemical cell comprises introducing the first feed stream substantially free of water. 
     
     
         6 . The method of  claim 1 , wherein introducing a first feed stream comprising carbon dioxide to a positive electrode comprises introducing the first feed stream to the positive electrode comprising an oxidation catalyst, the oxidation catalyst comprising a perovskite doped with a metal of palladium (Pd), platinum (Pt), iridium (Ir), ruthenium (Ru), rhodium (Rh), nickel (Ni), cobalt (Co), or a combination thereof. 
     
     
         7 . The method of  claim 1 , wherein introducing a second feed stream comprising a nitrogen source to the negative electrode comprises introducing the second feed stream to the negative electrode comprising a reduction catalyst, the reduction catalyst comprising a metal hydroxide catalyst. 
     
     
         8 . The method of  claim 1 , wherein introducing a second feed stream comprising a nitrogen source to the negative electrode comprises reducing the gas at a temperature of about 500° C. or less. 
     
     
         9 . The method of  claim 1 , wherein introducing a second feed stream comprising a nitrogen source to the negative electrode comprises introducing the second feed stream comprising nitrogen, nitrogen monoxide, nitrogen dioxide, or a combination thereof. 
     
     
         10 . The method of  claim 1 , wherein applying a potential difference between the positive electrode and the negative electrode of the electrochemical cell to produce a second product stream comprises diffusing the hydrogen ions through the electrolyte and reacting the hydrogen ions with the nitrogen source to produce the ammonia. 
     
     
         11 . The method of  claim 1 , wherein applying a potential difference between the positive electrode and the negative electrode of the electrochemical cell to produce hydrogen ions, a first product stream comprising carbon monoxide, and a second feed stream comprising ammonia comprises simultaneously producing the carbon monoxide and the ammonia. 
     
     
         12 . The method of  claim 1 , further comprising introducing a stream comprising water to the negative electrode. 
     
     
         13 . A method for producing ammonia comprising:
 introducing a first feed stream comprising methane and carbon dioxide to a positive electrode of an electrochemical cell, the electrochemical cell comprising the positive electrode, a negative electrode, and an electrolyte between the positive electrode and the negative electrode and the positive electrode comprising an oxidation catalyst;   introducing a second feed stream comprising nitrogen gas to the negative electrode, the negative electrode comprising a reduction catalyst; and   applying a potential difference between the positive electrode and the negative electrode to oxidize the methane and carbon dioxide to produce carbon monoxide and to reduce the nitrogen gas to produce ammonia.   
     
     
         14 . The method of  claim 13 , wherein introducing a second feed stream to the negative electrode comprises interacting the second feed stream with the reduction catalyst comprising a metal hydroxide integrated into a doped perovskite or supported metal catalyst. 
     
     
         15 . The method of  claim 14 , wherein introducing a second feed stream to the negative electrode comprises interacting the second feed stream with the reduction catalyst comprising a comprising a metal hydroxide comprising a metal selected from the group of rhodium (Rh), ruthenium (Ru), palladium (Pd), platinum (Pt), iridium (Ir), nickel (Ni), cobalt (Co), or a combination thereof. 
     
     
         16 . The method of  claim 15 , wherein introducing a second feed stream to the negative electrode comprises introducing the second feed stream comprising water and one or more of dinitrogen, nitrogen monoxide, nitrogen dioxide, or a combination thereof. 
     
     
         17 . A system for producing ammonia comprising:
 an electrochemical cell comprising:   a positive electrode comprising an oxidation catalyst formulated to produce carbon monoxide;   a negative electrode comprising a reduction catalyst formulated to produce ammonia; and   an electrolyte between the positive electrode and the negative electrode.   
     
     
         18 . The system of  claim 17 , wherein the positive electrode comprises a supported metal catalyst. 
     
     
         19 . The system of  claim 17 , wherein the negative electrode comprises a reduction catalyst comprising a lanthanum-doped ceria doped with platinum (Pt), palladium (Pd), rhodium (Rh), ruthenium (Ru), iridium (Ir), or iron (Fe). 
     
     
         20 . The system of  claim 17 , wherein the negative electrode comprises a metal hydroxide catalyst.