Coal Upgrading Process Utilizing Nitrogen and/or Carbon Dioxide

Abstract

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

1 . An integrated coal upgrading and combustion process, comprising the steps of: 
 separating air into streams of oxygen-enriched air and nitrogen-enriched air;    heating the nitrogen-enriched air stream;    introducing the heated nitrogen-enriched air stream into a coal upgrading apparatus containing coal;    allowing the heated nitrogen-enriched air to contact the coal in the coal upgrading apparatus for a selected period of time;    introducing the stream of oxygen-enriched air and the coal from the coal upgrading apparatus to a combustion chamber;    combusting the coal and oxygen-enriched air in the combustion chamber thereby producing flue gas;    drying, purifying, and compressing the flue gas to produce a carbon dioxide-rich fluid;    introducing the carbon dioxide-rich fluid to the coal upgrading apparatus; and    allowing the carbon dioxide-rich fluid to contact the coal in the coal upgrading apparatus for a selected period of time.    
   
   
       2 . The process of  claim 1 , further comprising the steps of: 
 collecting some of the flue gas from the combustion chamber before said drying, purifying, and compressing step is performed; and    combining the collected flue gas with the stream oxygen-enriched gas being introduced to the combustion chamber.    
   
   
       3 . The process of  claim 1 , further comprising the steps of: 
 allowing the carbon dioxide-rich fluid to exit the coal upgrading apparatus and into a first cleaning unit, wherein contact between the carbon dioxide-rich fluid and the coal in the coal upgrading apparatus results in solvation of some non-polar constituents of the coal into the carbon dioxide-rich fluid;    separating out some of the carbon dioxide from the combined carbon dioxide-rich fluid and the non-polar constituents at the first cleaning unit;    introducing the separated out carbon dioxide back into the coal upgrading apparatus;    removing at least some of a volatile component content of the non-polar constituents from non-polar constituents; and    introducing the separated volatile content into the combustion chamber.    
   
   
       4 . The process of  claim 1 , wherein, during said step of allowing the carbon dioxide-rich fluid to contact, the coal upgrading apparatus is sealed and has a pressure greater than ambient.  
   
   
       5 . The process of  claim 1 , wherein the carbon dioxide-rich fluid is a liquid.  
   
   
       6 . The process of  claim 1 , wherein the carbon dioxide-rich fluid is a gas.  
   
   
       7 . The process of  claim 1 , wherein the carbon dioxide-rich fluid has a pressure of no less than 1,000 psia.  
   
   
       8 . The process of  claim 1 , further comprising the steps of: 
 allowing the nitrogen-enriched air to exit the coal upgrading apparatus and into a second cleaning unit, wherein contact between the nitrogen-enriched air 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-enriched air at the second cleaning unit to produce dried nitrogen-enriched air; and    introducing the dried nitrogen-enriched air into the coal upgrading apparatus.    
   
   
       9 . The process of  claim 1 , wherein, during said step of allowing the heated nitrogen-enriched air to contact, the coal upgrading apparatus is vented.  
   
   
       10 . The process of  claim 1 , wherein the stream of nitrogen-enriched air is heated with heat produced by said combusting step.  
   
   
       11 . The process of  claim 1 , wherein the stream of nitrogen-enriched air is heated with heat produced by a flame separate from said combusting step.  
   
   
       12 . The process of  claim 1 , wherein the stream of nitrogen-enriched air is heated to a temperature of greater than 100° C.  
   
   
       13 . The process of  claim 1 , wherein the oxygen-enriched gas has an oxygen concentration in a range of from 21% to 99.5%.  
   
   
       14 . The process of  claim 1 , wherein the nitrogen-enriched gas has a nitrogen concentration in a range of from 79% to 99.5%.  
   
   
       15 . The process of  claim 1 , wherein the coal is not in a slurry with water.  
   
   
       16 . An integrated coal upgrading and combustion system, comprising: 
 a) an air separation unit having an oxygen-enriched gas stream outlet and a nitrogen-enriched gas stream outlet;    b) a heating device operably associated with said nitrogen-enriched air stream outlet;    c) a coal upgrading apparatus operatively associated with said heating device via a nitrogen feed line, said apparatus containing coal;    d) a combustion chamber fluidly communicating with said oxygen-enriched air stream outlet, said combustion chamber having a flue gas outlet and being configured and adapted to combust coal from said coal upgrading apparatus and oxygen-enriched gas from said air separation unit;    e) a flue gas drying, purifying, and compressing device fluidly communicating with said flue gas outlet; and    f) a carbon dioxide-rich fluid feed line, wherein: 
 i) said drying, purifying, and compressing device is configured and adapted to dry, purify, and compress flue gas received from said flue gas outlet to produce a carbon dioxide-rich fluid, and  
 ii) said drying, purifying, and compressing device fluidly communicates with said coal upgrading apparatus via said carbon dioxide-rich fluid feed line.  
   
   
   
       17 . The system of  claim 16 , further comprising: 
 an oxidant line adapted and configured to facilitate fluid communication between said oxygen-enriched gas stream outlet and said combustion chamber;    a flue gas recycle line fluidly communicating with said drying, purifying, and compressing device and said oxidant line; and    a mixing element disposed at a location wherein said flue gas recycle line and said oxidant line fluidly communicate, said mixing element adapted and configured to mix flue gas received from said flue gas recycle line with oxidant from said oxygen-enriched gas stream outlet.    
   
   
       18 . The system of  claim 16 , further comprising a first cleaning unit fluidly communicating with said coal upgrading apparatus via a carbon dioxide vent line and via said carbon dioxide-rich fluid feed line, said first cleaning unit also fluidly communicating with said combustion chamber via a volatiles line, wherein said first cleaning unit is configured and adapted to: 
 receive carbon dioxide-rich fluid from said coal upgrading apparatus containing a mixture of carbon dioxide and non-polar constituents there from;    separate at least some of carbon dioxide from the mixture of carbon dioxide and non-polar constituents;    direct the separated carbon dioxide to said coal upgrading apparatus via said carbon dioxide-rich fluid feed line;    separate out least some of a volatile component content of the non-polar constituents from the non-polar constituents; and    direct the separated volatile component content to said combustion chamber via said volatiles line.    
   
   
       19 . The system of  claim 16 , further comprising a second cleaning unit fluidly communicating with said coal upgrading unit via a nitrogen vent line and a nitrogen return line, wherein said first cleaning unit is configured and adapted to: 
 receive a mixture of nitrogen-enriched air and moisture from said coal upgrading apparatus via said nitrogen vent line;    separate at least some moisture from the mixture of nitrogen-enriched air and moisture to produce dried nitrogen-enriched air; and    direct the dried nitrogen-enriched air into said coal upgrading apparatus.    
   
   
       20 . The system of  claim 16 , further comprising a heat exchanger adapted and configured to heat nitrogen-enriched air from said nitrogen-enriched air stream outlet with heat produced from combustion of coal and oxygen-enriched air in said combustion chamber.  
   
   
       21 . 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 and S and N bearing compounds.    
   
   
       22 . 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.    
   
   
       23 . The process of  claim 21 , wherein, during said step of allowing the heated nitrogen-containing gas to contact, the coal upgrading apparatus is vented.  
   
   
       24 . The process of  claim 21 , 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.    
   
   
       25 . The process of  claim 24 , wherein the combustion chamber is part of a boiler.  
   
   
       26 . The process of  claim 21 , wherein the nitrogen-containing gas is heated to a temperature of greater than 100° C.  
   
   
       27 . The process of  claim 21 , wherein the nitrogen-containing gas has a nitrogen concentration in a range of from 79% to 99.5%.  
   
   
       28 . A process of upgrading coal with carbon dioxide, comprising the steps of: 
 providing a carbon dioxide-containing fluid having a carbon dioxide concentration greater than that of air;    allowing the carbon dioxide-containing fluid to contact coal in a coal upgrading apparatus for a period of time, wherein the coal is not in a water slurry;    allowing the carbon dioxide-containing fluid to be vented from the coal upgrading apparatus thereby removing at least some non-polar constituents from the coal.    
   
   
       29 . The process of  claim 28 , 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.  
   
   
       30 . The process of  claim 28 , wherein the coal is not in a slurry with water.  
   
   
       31 . The process of  claim 28 , further comprising the steps of: 
 separating air into streams of oxygen-enriched air and nitrogen-enriched air;    introducing the stream of oxygen-enriched air and the coal from the coal upgrading apparatus to a combustion chamber;    combusting the coal and oxygen-enriched air in the combustion chamber thereby producing flue gas; and    drying, purifying, and compressing the flue gas to produce the carbon dioxide-containing fluid.    
   
   
       32 . The process of  claim 31 , further comprising the steps of: 
 collecting some of the flue gas from the combustion chamber before said drying, purifying, and compressing step is performed; and    combining the collected flue gas with the stream oxygen-enriched gas being introduced to the combustion chamber.    
   
   
       33 . The process of  claim 32 , further comprising the steps of: 
 allowing the carbon dioxide-containing fluid to exit the coal upgrading apparatus and into a first cleaning unit, wherein contact between the carbon dioxide-containing fluid and the coal in the coal upgrading apparatus results in dissolution of some non-polar constituents of the coal into the carbon dioxide-containing fluid;    separating out some of the carbon dioxide from the combined carbon dioxide-containing fluid and the non-polar constituents at the first cleaning unit;    introducing the separated out carbon dioxide back into the coal upgrading apparatus;    removing at least some of a volatile component content of the non-polar constituents from non-polar constituents; and    introducing the separated volatile content into the combustion chamber.    
   
   
       34 . The process of  claim 28 , wherein the carbon dioxide-containing fluid is a liquid.  
   
   
       35 . The process of  claim 28 , wherein the carbon dioxide-containing fluid is a gas.  
   
   
       36 . The process of  claim 28 , wherein the carbon dioxide-containing fluid has a pressure of no less than 1,000 psia.