Inhibition of Spontaneous Combustion in Low-Rank Coals

Abstract

A method for treating coal to reduce spontaneous combustion by reducing an exothermic heat of adsorption after the coal has begun to dry and when the coal is subsequently exposed to a liquid water is described. A source of a fluid pressure of a diluted hydrocarbon mixture is provided. A hydrocarbon in the mixture is a hydrocarbon emulsion of mineral when the coal is subsequently exposed to a liquid water oil, fuel oil, asphalt, or coal tar emulsions. A volume of the diluted hydrocarbon mixture is applied to a stream of freshly-mined and undried coal to provide a water-proofing of the coal to prevent water uptake after exposure to precipitation or flooding during transport and storage of the coal. The treated coal is loaded into a bulk pile. A temperature change trend in the bulk pile is reversed wherein a temperature of the bulk pile trends towards an ambient temperature rather than trending to a temperature higher than the ambient temperature.

1 . A method for treating coal to reduce spontaneous combustion by reducing an exothermic heat of adsorption after the coal has begun to dry and when the coal is subsequently exposed to a liquid water comprising the steps of:
 providing a source of a fluid pressure of a hydrocarbon; and   applying the hydrocarbon to a stream of coal.   
     
     
         2 . The method of  claim 1  wherein the hydrocarbon is a hydrocarbon emulsion. 
     
     
         3 . The method of  claim 2  wherein a low-level amount of the hydrocarbon emulsion is applied to the coal as a percentage of a weight of the coal. 
     
     
         4 . The method of  claim 3  wherein the hydrocarbon emulsion is selected from the group consisting of: mineral oil, fuel oil, asphalt, and coal tar emulsions. 
     
     
         5 . The method of  claim 4  wherein the coal is freshly-mined and un-dried. 
     
     
         6 . The method of  claim 5  wherein the hydrocarbon emulsion reduces self-heating of the coal caused by exothermic heat of absorption. 
     
     
         7 . A method for treating coal to reduce spontaneous combustion by reducing an exothermic heat of adsorption after the coal has begun to dry and when the coal is subsequently exposed to a liquid water comprising the steps of:
 providing a source of a fluid pressure of a silicone; and   applying the silicone to a stream of coal.   
     
     
         8 . The method of  claim 7  wherein the silicone is a silicone emulsion. 
     
     
         9 . The method of  claim 8  wherein a low-level amount of the silicone emulsion is applied to the coal as a percentage of a weight of the coal. 
     
     
         10 . A method for treating coal to reduce spontaneous combustion by reducing an exothermic heat of adsorption after the coal has begun to dry and when the coal is subsequently exposed to a liquid water comprising the steps of:
 providing a source of a fluid pressure of a silane; and   applying the silane to a stream of coal.   
     
     
         11 . The method of  claim 10  wherein a low-level amount of the silane is applied to the coal as a percentage of a weight of the coal. 
     
     
         12 . A method for treating coal to reduce spontaneous combustion by reducing an exothermic heat of adsorption after the coal has begun to dry and when the coal is subsequently exposed to a liquid water comprising the step of waterproofing a freshly-mined coal to prevent water uptake after exposure to precipitation or flooding during transport and storage of the freshly-mined coal. 
     
     
         13 . The method of  claim 12  further comprising the steps of:
 providing a source of a fluid pressure of a hydrocarbon; and 
 applying the hydrocarbon to a stream of freshly-mined and undried coal. 
 
     
     
         14 . The method of  claim 13  wherein the applying step includes application of a low-level amount of the hydrocarbon as a percentage of the weight of the coal. 
     
     
         15 . The method of  claim 14  wherein the hydrocarbon is a hydrocarbon emulsion. 
     
     
         16 . The method of  claim 15  wherein the low-level amount of the hydrocarbon emulsion is not more than 2 lb (0.9 kg) per ton of the coal. 
     
     
         17 . The method of  claim 16  wherein the hydrocarbon emulsion is diluted in liquid water prior to the applying step. 
     
     
         18 . The method of  claim 17  wherein a diluted mixture of the hydrocarbon emulsion and the liquid water contains less than 80 parts liquid water. 
     
     
         19 . The method of  claim 18  wherein the diluted mixture contains between 19 and 79 parts liquid water. 
     
     
         20 . The method of  claim 19  wherein an application rate of the diluted mixture is 2.5 to 10 gallons of diluted mixture per ton of freshly-mined and undried coal. 
     
     
         21 . The method of  claim 20  wherein the hydrocarbon emulsion is selected from the group consisting of: mineral oil, fuel oil, asphalt, and coal tar emulsions. 
     
     
         22 . The method of  claim 21  further comprising the step of:
 developing a water repellency of the freshly-mined and undried coal by allowing the coal to dry under ambient conditions. 
 
     
     
         23 . The method of  claim 21  further comprising the steps of:
 loading the freshly-mined and undried coal into a bulk pile subsequent to the applying step; and 
 reversing a temperature change trend in the bulk pile wherein a temperature of the bulk pile trends towards an ambient temperature rather than trending to a temperature higher than the ambient temperature. 
 
     
     
         24 .- 36 . (canceled)