Ammonia synthesis for fertilizer production

Abstract

A method for synthesizing ammonia for agricultural fertilizers employs water (H2O) as the source of hydrogen (H2) in ammonia (NH3) synthesis, and gathers carbon monoxide (CO) as a limiting reagent for combining in a WGS (Water-Gas-Shift) reaction for producing hydrogen. The WGS reaction employs CO with the water to produce Carbon Dioxide (CO2) and H2, consuming undesirable CO from other industrial applications. A by-product of the process includes generating 1.5 mole of CO2 for each mole of ammonia synthesized. An intermediate step consumes 3 moles of hydrogen for each mole of Nitrogen (N2). The use of methane gas is avoided as the process employs CO and the WGS reaction as an exclusive source of H2 without introducing methane (CH4). A downstream synthesis of ammonia can be done through a fuel cell to produce electricity for the ammonia synthesis for further sustainability.

What is claimed is: 
     
         1 . A method for synthesizing ammonia, comprising:
 receiving carbon monoxide (CO) from an industrial process;   providing the received carbon monoxide to a hydrogen separator for reacting the carbon monoxide with water from a water source for producing hydrogen (H 2 );   combining the hydrogen with nitrogen from a nitrogen reactor for synthesizing ammonia, the hydrogen generated exclusively from the water provided to the hydrogen separator.   
     
     
         2 . The method of  claim 1  wherein the hydrogen separator is a catalyzed membrane reactor having a palladium membrane, further comprising passing the hydrogen through the palladium membrane. 
     
     
         3 . The method of  claim 2  wherein combining the hydrogen further comprises combining the hydrogen with nitrogen in an ammonia reactor at a 3:1 molar ratio, heating and pressurizing the combined hydrogen and nitrogen for passing resulting ammonia (NH 3 ) through a membrane for separating ammonia, and recirculating the hydrogen and nitrogen for additional passes, each pass yielding separated ammonia. 
     
     
         4 . The method of  claim 3  wherein the CO is reacted with the water at a molar ratio of substantially around 2:1 at a temperature of 450° C., and the hydrogen and nitrogen is combined at 450° C. and at a pressure of 200 bar. 
     
     
         5 . The method of  claim 2  further comprising reacting the hydrogen and nitrogen in an ammonia reactor using an iron-chromium catalyst. 
     
     
         6 . The method of  claim 1  further comprising receiving the CO from a carbon black refining operation, by capturing exhaust gases from the carbon black refining and passing the captured exhaust gases through a scrubber for separating sulfides as well as other sources such as steel mills and electricity plants. 
     
     
         7 . The method of  claim 6  further comprising coupling thermal inputs of the carbon monoxide scrubber and the hydrogen separation for facilitating a self-sustaining electrical generation. 
     
     
         8 . The method of  claim 2  further comprising directing heat from the hydrogen separator to an ammonia reactor for synthesizing the ammonia. 
     
     
         9 . The method of  claim 8  further comprising providing heat via a thermal conduit from an industrial combustion process, the thermal conduit responsive to thermal energy vented as a byproduct from the industrial combustion process for providing heat to the hydrogen separator. 
     
     
         10 . The method of  claim 3  further comprising:
 receiving the synthesized ammonia into a module, the module having an electrolyte, a separator, and terminals on opposed sides of the separator; and 
 converting the received ammonia into urea, the conversion resulting in an ionic flow across the separator for generating a voltage differential between the opposed terminals. 
 
     
     
         11 . A system for synthesizing ammonia from byproducts of industrial operations, comprising:
 a scrubber and/or membrane for receiving exhaust, the exhaust including carbon monoxide, and operative to remove sulfur based compounds from the exhaust;   a CO mixer in communication with the scrubber for combining the scrubbed carbon monoxide with water;   a hydrogen separator for receiving the carbon monoxide and water, the hydrogen separator having a membrane for separating and passing purified hydrogen (H 2 );   a hydrogen mixer for combining the separated hydrogen with nitrogen; and   an ammonia reactor for receiving the hydrogen and nitrogen, and combining the hydrogen and nitrogen under applied heat and pressure for synthesizing ammonia, the hydrogen sourced exclusively from the water passed through the hydrogen separator membrane.   
     
     
         12 . The system of  claim 11  wherein the hydrogen separator is a catalyzed membrane reactor having a palladium membrane, further comprising passing the hydrogen through the palladium membrane. 
     
     
         13 . The system of  claim 12  wherein the CO is reacted with the water at a molar ratio of 2:1 at a temperature of 450o C, and the hydrogen and nitrogen is combined at 450° C. and at a pressure of 200 bar,
 the ammonia reactor responsive to combining the hydrogen further comprises combining the hydrogen with nitrogen in an ammonia reactor at a 3:1 molar ratio, heating and pressurizing the combined hydrogen and nitrogen for passing resulting ammonia (NH 3 ) through a membrane for separating ammonia, and recirculating the hydrogen for additional passes, each pass yielding separated ammonia. 
 
     
     
         14 . The system of  claim 13  further comprising an iron-chromium catalyst in the ammonia reactor, the iron-chromium catalyst responsive to reacting the hydrogen and nitrogen. 
     
     
         15 . The system of  claim 11  further comprising an exhaust flow from a carbon black refining operation, the hydrogen separator configured to capture exhaust gases from the carbon black refining and passing the captured exhaust gases through a scrubber and/or membrane for separating sulfides from the CO. 
     
     
         16 . The system of  claim 15  further comprising a thermocouple for coupling thermal inputs of the carbon monoxide scrubber and the hydrogen separation. 
     
     
         17 . The system of  claim 15  further comprising a thermal conduit from the carbon black refining process, the thermal conduit responsive to thermal energy vented as a byproduct from the carbon black process for providing heat to the hydrogen separator, the thermal conduit further configured for directing heat from the hydrogen separator to an ammonia reactor for synthesizing the ammonia. 
     
     
         18 . The system of  claim 11  further comprising:
 an electrical module for receiving the synthesized ammonia, the electrical module having an electrolyte, a separator, and terminals on opposed sides of the separator, 
 the ammonia reactor disposed in the module and configured to convert the received ammonia into urea, the conversion resulting in an ionic flow across the separator for generating a voltage differential between the opposed terminals. 
 
     
     
         19 . A hydrogen separator device for supporting an ammonia reactor, comprising:
 a scrubber and or membrane for receiving exhaust, the exhaust including carbon monoxide, and removing sulfur based compounds from the exhaust;   a CO mixer for combining the scrubbed carbon monoxide with water;   a hydrogen separator having a membrane for separating and passing purified hydrogen (H 2 );   a hydrogen mixer for combining the separated hydrogen with nitrogen;   an ammonia reactor for receiving the hydrogen and nitrogen, and combining the hydrogen and nitrogen under applied heat and pressure for synthesizing ammonia, the hydrogen sourced exclusively from the water passed through the hydrogen separator membrane; and   a conduit to a carbon black refining operation, the conduit for capturing exhaust gases from the carbon black refining and passing the captured exhaust gases through a scrubber and or membrane for separating sulfides from the CO.   
     
     
         20 . The device of  claim 19  further comprising a nitrogen reactor responsive to the hydrogen for combining the hydrogen with nitrogen at a 3:1 molar ratio, heating and pressurizing the combined hydrogen and nitrogen for passing resulting ammonia (NH 3 ) through a membrane or a kettle condenser for separating ammonia, and recirculating the hydrogen for additional passes, each pass yielding separated ammonia.