Coal upgrading utilizing nitrogen

Abstract

Coal is upgraded through use of carbon dioxide and/or nitrogen and optionally integrated with a combustion process.

1 . A process of upgrading coal with heated nitrogen comprising the steps of: 
 heating a nitrogen-containing gas having a nitrogen concentration greater than that of air;    allowing the heated nitrogen-containing gas to contact coal in a coal upgrading apparatus for a selected period of time; and    allowing the heated nitrogen-containing gas to be vented from the coal upgrading apparatus thereby removing at least some moisture from the coal.    
     
     
         2 . The process of claim  21 , further comprising the steps of: 
 allowing the nitrogen-containing gas to exit the coal upgrading apparatus and into a second cleaning unit, wherein contact between the nitrogen-containing gas and the coal in the coal upgrading apparatus results in removal of some of the moisture in the coal;    separating out moisture from the nitrogen-containing gas at the second cleaning unit to produce dried nitrogen-containing gas; and    introducing the dried nitrogen-containing gas into the coal upgrading apparatus.    
     
     
         3 . The process of  claim 1 , wherein, during said step of allowing the heated nitrogen-containing gas to contact, the coal upgrading apparatus is vented.  
     
     
         4 . The process of  claim 1 , further comprising the steps of: 
 separating air into streams of oxygen-enriched air and nitrogen-enriched air, wherein the nitrogen-containing gas comprises the nitrogen-enriched air;    introducing the stream of oxygen-enriched air and the coal from the coal upgrading apparatus to a combustion chamber; and    combusting the coal and oxygen-enriched air in the combustion chamber thereby producing heat, wherein said step of heating a nitrogen-containing gas is accomplishing by imparting heat from the combustion chamber to the nitrogen-enriched air.    
     
     
         5 . The process of  claim 4 , wherein said step of the combustion chamber is part of a boiler.  
     
     
         6 . The process of  claim 4 , wherein said step of combusting produces a flue gas and the flue gas is thereafter dried, purified, and compressed.  
     
     
         7 . The process of  claim 1 , wherein the nitrogen-containing gas is heated to a temperature of greater than 100° C.  
     
     
         8 . The process of  claim 1 , wherein the nitrogen-containing gas has a nitrogen concentration in a range of from 79% to 99.5%.  
     
     
         9 . The process of  claim 1 , further comprising the steps of: 
 providing a carbon dioxide-containing fluid having a carbon dioxide concentration greater than that of air; and    allowing the carbon dioxide-containing fluid to contact coal in the coal upgrading apparatus for a period of time.    
     
     
         10 . The process of  claim 9 , wherein the coal upgrading apparatus is at a pressure greater than ambient and is sealed during contact of the carbon dioxide-containing fluid and coal.  
     
     
         11 . The process of  claim 1 , wherein the coal is not in a water slurry.  
     
     
         12 . The process of  claim 1 , wherein said step of allowing the heated nitrogen-containing gas to contact removes at least some sulfur-containing compounds and at least some nitrogen-containing compounds from the coal.  
     
     
         13 . The process of  claim 9 , wherein the carbon dioxide-containing fluid is a liquid.  
     
     
         14 . The process of  claim 9 , wherein the carbon dioxide-containing fluid is a gas.  
     
     
         15 . The process of  claim 9 , wherein the carbon dioxide-containing fluid has a pressure of no less than 1,000 psia.  
     
     
         16 . The process of  claim 4 , wherein the oxygen-enriched gas has an oxygen concentration in a range of from 21% to 99.5%.  
     
     
         17 . The process of  claim 1 , wherein the nitrogen-enriched gas has a nitrogen concentration in a range of from 79% to 99.5%.