Process for treating coal with a magnetic gradient to reduce sulfur dioxide emissions

Abstract

A process for treating high sulfur coal to reduce sulfur dioxide emissions when the coal is burned, which includes placing the coal in an aqueous basic soluble media saturated with a calcium salt which is pressurized with carbon dioxide. The pressure is then released to fracture the coal, and the aqueous fluids are substantially removed from the fractured coal by drying. A magnetic field is applied to the fractured coal to orient the calcium ions and to distribute the ions more uniformly on the fractured coal. The distributed calcium produces calcium sulfate when the coal is burned.

1 . A process for treating coal to reduce sulfur dioxide emissions when the coal is burned, which comprises: 
 a. placing the coal in an aqueous basic soluble media saturated with a calcium salt and then pressurizing the coal with carbon dioxide and then releasing the pressure to fracture the coal causing the calcium salt to penetrate the coal;    b. removing some or substantially all of the aqueous fluids from the fractured coal by drying;    c. applying a magnetic field to the fractured coal to orient the calcium ions and to distribute the ions more uniformly on the fractured coal; and    d. wherein the distributed calcium produces calcium sulfate when the coal is burned.    
   
   
       2 . The process of  claim 1 , wherein the pressure of the carbon dioxide is greater than 1 atm.  
   
   
       3 . The process of  claim 1 , wherein prior to fracturing the coal, the coal is reduced to a size of less than about five centimeters (cm) maximum diameter.  
   
   
       4 . The process of  claim 3 , wherein the coal is reduced to a size of less than about 3 cm maximum diameter.  
   
   
       5 . The process of  claim 4 , wherein the coal is reduced to a size of about 3 microns to about 4 millimeters.  
   
   
       6 . The process of  claim 5 , wherein the coal is reduced to a size of about 3 mm to about 4 mm.  
   
   
       7 . The process of  claim 1 , wherein the releasing of the pressure of the carbon dioxide is between 10 seconds and 10 minutes.  
   
   
       8 . The process of  claim 7 , wherein the releasing of the pressure of the carbon dioxide is between 10 seconds and 60 seconds.  
   
   
       9 . The process of  claim 1 , wherein the carbon dioxide atmosphere is substantially pure carbon dioxide.  
   
   
       10 . The process of  claim 1 , wherein the carbon dioxide atmosphere has a pressure of 10 at least 50 psi.  
   
   
       11 . The process of  claim 10 , wherein pressure is about 100 psi to about 300 psi.  
   
   
       12 . The process of  claim 1 , wherein the coal is immersed within the aqueous composition to form a slurry.  
   
   
       13 . The process of  claim 12 , wherein the slurry is agitated.  
   
   
       14 . The process of  claim 1 , wherein the aqueous composition is in contact with the coal by spraying the coal with the aqueous composition.  
   
   
       15 . The process of claim  1 I wherein the aqueous composition exhibits a pH of at least about 10.  
   
   
       16 . The process of  claim 15 , wherein the aqueous composition exhibits a pH of at least about 13.8.  
   
   
       17 . The process of  claim 1 , wherein the aqueous composition comprises a soluble basic salt.  
   
   
       18 . The process of  claim 17 , wherein the aqueous composition comprises sodium hydroxide, calcium carbonate, and combinations thereof.  
   
   
       19 . The process of  claim 1 , wherein the aqueous composition exhibits a pH of at least about 13.5 and comprises sodium hydroxide, calcium oxide, calcium carbonate, and combinations thereof.  
   
   
       20 . The process of  claim 1 , wherein the coal comprises more than about 0.5 percent by weight of sulfur.  
   
   
       21 . The process of  claim 20 , wherein the coal comprises more than about 0.8 percent by weight of sulfur.  
   
   
       22 . The process of  claim 1 , wherein the coal resulting from the treatment of the process of  claim 1  has sufficient calcium carbonate deposited within it to provide an amount sufficient to provide a molar ratio of Ca:S of at least 1.  
   
   
       23 . The process of  claim 19 , wherein the resulting coal has about 1.0 percent by weight calcium carbonate associated therewith.  
   
   
       24 . The process of  claim 1 , wherein the fractured coal is fully immersed in the aqueous solution.  
   
   
       25 . The process of  claim 1  wherein the coal is a high sulfur coal.  
   
   
       26 . A process for producing energy from burning high sulfur coal while reducing the sulfur dioxide content of the emission from such burning, which process comprises depositing calcium salts within fractures in fractured coal and burning the resulting calcium salts-containing high sulfur coal at a high temperature.  
   
   
       27 . The process of  claim 26 , wherein the coal comprises at least 0.5 percent by weight sulfur and calcium salts deposited within the fractures of the coal in an amount sufficient to provide a Ca:S molar ratio of at least 1.3:1.0.  
   
   
       28 . The process of  claim 27 , wherein the coal has a particle size of less than about 5 cm.  
   
   
       29 . The process of  claim 28 , wherein the coal has a particle size of about 50 mm to about 2 mm.  
   
   
       30 . The process of  claim 26 , wherein the coal is powdered and is burned at a temperature of about 1600° F. to about 3500° F. by blowing it into a furnace, mixing it with a source of oxygen, and igniting the mixture.  
   
   
       31 . A process for increasing the amount of calcium sulfate produced as a result of burning high sulfur coal, while at the same time reducing the sulfur dioxide emissions from such burning, which process comprises burning a vacuum fractured high sulfur coal having calcium salts deposited within fractures in the coal and recovering the calcium sulfate produced as a result of such burning.  
   
   
       32 . The process of  claim 31 , wherein the coal comprises at least 0.5 percent by weight sulfur and further comprises a calcium salt deposited within the fractures in the coal in an amount sufficient to provide a Ca:S molar ratio of at least 1.0.  
   
   
       33 . The process of  claim 32 , wherein the coal has a particle size of less than about 5 cm.  
   
   
       34 . The process of  claim 33 , wherein the coal has a particle size of about 5 mm to about 2 mm.  
   
   
       35 . The process of  claim 31 , wherein the coal has a particle size of less than 1 inch and is burned in a Stoker furnace at about 1600° F. to about 2600° F.  
   
   
       36 . The process of  claim 31 , wherein the coal is powdered and is burned at about 3200° F. to about 3700° F. by blowing it into a furnace, mixing it with a source of oxygen, and igniting the mixture.  
   
   
       37 . An apparatus for treating high sulfur coal with an aqueous composition under pressure, which apparatus comprises: 
 a. a pressurizable container suitable for holding the coal to be treated;    b. a first inlet to allow the aqueous composition to enter the pressurizable container and to make contact with the coal;    c. a mechanism to remove the aqueous composition from the pressurizable container;    d. a second inlet to allow carbon dioxide to enter the pressurizable container under a pressure higher than atmospheric pressure;    e. a source of pressurized carbon dioxide connected to the second inlet;    f. an outlet to remove the coal from the pressurizable container after the carbon dioxide pressure is released; and    g. a magnetic gradient which the fractured coal is passed through.