Low-sulfur coal production method

Abstract

A low-sulfur coal production method having an excellent desulfurization effect includes bringing coal into contact with a chemical material that is a mixed solution of hydrogen peroxide and acetic anhydride to remove sulfur in the coal. It is preferred that the molar ratio of the acetic anhydride to the hydrogen peroxide is 0.5 to 12.0 inclusive. It is preferred that the acetic anhydride is mixed with the hydrogen peroxide before the chemical material is brought into contact with the coal and the chemical material is brought into contact with the coal after 10 minutes or more has elapsed since the mixing.

1 .- 11 . (canceled) 
     
     
         12 . 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 anhydride to thereby remove sulfur in the coal,   wherein a molar ratio between the acetic anhydride and the hydrogen peroxide (acetic anhydride/hydrogen peroxide) is not less than 0.5 and not more than 12.0,   wherein the acetic anhydride and the hydrogen peroxide are mixed before the chemical agent is brought into contact with the coal, and   wherein when 10 minutes or more have elapsed after the acetic anhydride and the hydrogen peroxide are mixed, the chemical agent is brought into contact with the coal.   
     
     
         13 . The low-sulfur coal production method according to  claim 12 ,
 wherein a mass ratio between the chemical agent and the coal (chemical agent/coal) is not less than 1.0, and   wherein a temperature of the chemical agent at a time of being brought into contact with the coal is not less than 5° C. but not more than 30° C.   
     
     
         14 . The low-sulfur coal production method according to  claim 12 ,
 wherein the coal comprises sub-bituminous coal.   
     
     
         15 . The low-sulfur coal production method according to  claim 13 ,
 wherein the coal comprises sub-bituminous coal.   
     
     
         16 . The low-sulfur coal production method according to  claim 12 ,
 wherein the coal that has been brought into contact with the chemical agent is heat-treated at a heat treatment temperature of not less than 150° C., and   wherein a heating rate at which the coal that has been brought into contact with the chemical agent is heated to the heat treatment temperature is not less than 10° C./min.   
     
     
         17 . The low-sulfur coal production method according to  claim 13 ,
 wherein the coal that has been brought into contact with the chemical agent is heat-treated at a heat treatment temperature of not less than 150° C., and   wherein a heating rate at which the coal that has been brought into contact with the chemical agent is heated to the heat treatment temperature is not less than 10° C./min.   
     
     
         18 . The low-sulfur coal production method according to  claim 14 ,
 wherein the coal that has been brought into contact with the chemical agent is heat-treated at a heat treatment temperature of not less than 150° C., and   wherein a heating rate at which the coal that has been brought into contact with the chemical agent is heated to the heat treatment temperature is not less than 10° C./min.   
     
     
         19 . The low-sulfur coal production method according to  claim 15 ,
 wherein the coal that has been brought into contact with the chemical agent is heat-treated at a heat treatment temperature of not less than 150° C., and   wherein a heating rate at which the coal that has been brought into contact with the chemical agent is heated to the heat treatment temperature is not less than 10° C./min.   
     
     
         20 . The low-sulfur coal production method according to  claim 12 ,
 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.   
     
     
         21 . The low-sulfur coal production method according to  claim 13 ,
 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.   
     
     
         22 . The low-sulfur coal production method according to  claim 14 ,
 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.   
     
     
         23 . The low-sulfur coal production method according to  claim 15 ,
 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.