Method for producing low-sulfur coal

Abstract

A method for producing low-sulfur coal having an excellent desulfurization effect. In the production method, coal is brought into contact with a chemical agent that is a mixed solution of hydrogen peroxide and acetic acid to remove sulfur in the coal. It is preferred that the molar ratio of the acetic acid to the hydrogen peroxide ((acetic acid)/(hydrogen peroxide)) is 1.2 to 60.0 inclusive. It is preferred that the acetic acid is mixed with the hydrogen peroxide before the chemical agent is brought into contact with the coal and the chemical agent is brought into contact with the coal after 30 minutes or more has elapsed since the mixing is performed.

1 - 16 . (canceled) 
     
     
         17 . A low-sulfur coal production method comprising:
 bringing coal into contact with a chemical agent which is a mixed solution of hydrogen peroxide and acetic acid to thereby remove sulfur in the coal,   wherein a molar ratio between the acetic acid and the hydrogen peroxide (acetic acid/hydrogen peroxide) is not less than 1.2 and not more than 60.0,   wherein the acetic acid and the hydrogen peroxide are mixed before the chemical agent is brought into contact with the coal, and   wherein when 30 minutes or more have elapsed after the acetic acid and the hydrogen peroxide are mixed, the chemical agent is brought into contact with the coal.   
     
     
         18 . A low-sulfur coal production method comprising:
 bringing coal into contact with a chemical agent which is an aqueous peracetic acid solution to thereby remove sulfur in the coal,   wherein a content of peracetic acid in the chemical agent is not less than 10.0 mass % and not more than 25.0 mass %.   
     
     
         19 . A low-sulfur coal production method comprising:
 bringing coal into contact with a chemical agent which is a mixed solution of hydrogen peroxide and formic acid to thereby remove sulfur in the coal,   wherein a molar ratio between the formic acid and the hydrogen peroxide (formic acid/hydrogen peroxide) is not less than 1.2 and not more than 60.0,   wherein the formic acid and the hydrogen peroxide are mixed before the chemical agent is brought into contact with the coal, and   wherein when 5 minutes or more have elapsed after the formic acid and the hydrogen peroxide are mixed, the chemical agent is brought into contact with the coal.   
     
     
         20 . The low-sulfur coal production method according to  claim 17 ,
 wherein a mass ratio between the chemical agent and the coal (chemical agent/coal) is not less than 1.0,   wherein a temperature of the chemical agent at a time of being brought into contact with the coal is not less than 10° C. but not more than 60° C.   
     
     
         21 . The low-sulfur coal production method according to  claim 19 ,
 wherein a mass ratio between the chemical agent and the coal (chemical agent/coal) is not less than 1.0,   wherein a temperature of the chemical agent at a time of being brought into contact with the coal is not less than 10° C. but not more than 60° C.   
     
     
         22 . The low-sulfur coal production method according to  claim 17 ,
 wherein the coal comprises sub-bituminous coal.   
     
     
         23 . The low-sulfur coal production method according to  claim 19 ,
 wherein the coal comprises sub-bituminous coal.   
     
     
         24 . The low-sulfur coal production method according to  claim 20 ,
 wherein the coal comprises sub-bituminous coal.   
     
     
         25 . The low-sulfur coal production method according to  claim 21 ,
 wherein the coal comprises sub-bituminous coal.   
     
     
         26 . The low-sulfur coal production method according to  claim 17 ,
 wherein the coal that has been brought into contact with the chemical agent is brought into contact with a hydrogen peroxide solution having a temperature of not more than 40° C.,   wherein a concentration of the hydrogen peroxide solution is not less than 2.0 mass %, and   wherein a mass ratio between the hydrogen peroxide solution and the coal (hydrogen peroxide solution/coal) is not less than 1.0.   
     
     
         27 . The low-sulfur coal production method according to  claim 19 ,
 wherein the coal that has been brought into contact with the chemical agent is brought into contact with a hydrogen peroxide solution having a temperature of not more than 40° C.,   wherein a concentration of the hydrogen peroxide solution is not less than 2.0 mass %, and   wherein a mass ratio between the hydrogen peroxide solution and the coal (hydrogen peroxide solution/coal) is not less than 1.0.   
     
     
         28 . The low-sulfur coal production method according to  claim 20 ,
 wherein the coal that has been brought into contact with the chemical agent is brought into contact with a hydrogen peroxide solution having a temperature of not more than 40° C.,   wherein a concentration of the hydrogen peroxide solution is not less than 2.0 mass %, and   wherein a mass ratio between the hydrogen peroxide solution and the coal (hydrogen peroxide solution/coal) is not less than 1.0.   
     
     
         29 . The low-sulfur coal production method according to  claim 21 ,
 wherein the coal that has been brought into contact with the chemical agent is brought into contact with a hydrogen peroxide solution having a temperature of not more than 40° C.,   wherein a concentration of the hydrogen peroxide solution is not less than 2.0 mass %, and   wherein a mass ratio between the hydrogen peroxide solution and the coal (hydrogen peroxide solution/coal) is not less than 1.0.   
     
     
         30 . The low-sulfur coal production method according to  claim 22 ,
 wherein the coal that has been brought into contact with the chemical agent is brought into contact with a hydrogen peroxide solution having a temperature of not more than 40° C.,   wherein a concentration of the hydrogen peroxide solution is not less than 2.0 mass %, and   wherein a mass ratio between the hydrogen peroxide solution and the coal (hydrogen peroxide solution/coal) is not less than 1.0.   
     
     
         31 . The low-sulfur coal production method according to  claim 23 ,
 wherein the coal that has been brought into contact with the chemical agent is brought into contact with a hydrogen peroxide solution having a temperature of not more than 40° C.,   wherein a concentration of the hydrogen peroxide solution is not less than 2.0 mass %, and   wherein a mass ratio between the hydrogen peroxide solution and the coal (hydrogen peroxide solution/coal) is not less than 1.0.   
     
     
         32 . The low-sulfur coal production method according to  claim 24 ,
 wherein the coal that has been brought into contact with the chemical agent is brought into contact with a hydrogen peroxide solution having a temperature of not more than 40° C.,   wherein a concentration of the hydrogen peroxide solution is not less than 2.0 mass %, and   wherein a mass ratio between the hydrogen peroxide solution and the coal (hydrogen peroxide solution/coal) is not less than 1.0.   
     
     
         33 . The low-sulfur coal production method according to  claim 25 ,
 wherein the coal that has been brought into contact with the chemical agent is brought into contact with a hydrogen peroxide solution having a temperature of not more than 40° C.,   wherein a concentration of the hydrogen peroxide solution is not less than 2.0 mass %, and   wherein a mass ratio between the hydrogen peroxide solution and the coal (hydrogen peroxide solution/coal) is not less than 1.0.