Fuel log of recycled materials and methods of manufacture

Abstract

A combustible solid fuel source in the form of a log is formed from a base material of a cellulosic or fibrous organic material which is compressed in a screw press up to 20,000 pounds to a density in the range 50 to 85 lbs/cu ft. The log is cut to length and partly immersed in a bath of a combustible vegetable oil which absorbed into the base material as it slightly expands such that the content of oil is less than 50% by weight and generally of the order of 30% where the log is dry to the touch and the oil is entirely contained without the need for an external covering of wax or the like. The base material is selected from lumber, agricultural waste or animal waste to contain fibers such that the content of ash when the source has been fully combusted is generally less than 2% by weight with very little contaminants.

1 . A combustible solid fuel source comprising:
 a base material formed of a cellulosic or fibrous organic material which is compressed to a density of at least 50 lbs/cu ft;   a combustible oil absorbed into the base material such that the content of oil is less than 50% by weight;   the base material being arranged such that the content of ash when the source has been fully combusted is less than 10% by weight.   
     
     
         2 . The fuel source according to  claim 1  wherein the oil content is less than 35%. 
     
     
         3 . The fuel source according to  claim 1  wherein the density of the base material lies in the range 50 to 85 lbs/cu ft. 
     
     
         4 . The fuel source according to  claim 1  wherein the oil is a vegetable oil. 
     
     
         5 . The fuel source according to  claim 1  wherein the ash content is less than 2%. 
     
     
         6 . The fuel source according to  claim 1  wherein the quantity of oil is arranged such that the amount of oil is substantially the maximum which can be absorbed while the oil has no tendency to escape from the base material. 
     
     
         7 . The fuel source according to  claim 1  wherein the base material containing the oil is dry to the touch. 
     
     
         8 . The fuel source according to  claim 1  wherein the base material has an exterior surface which is substantially free from an exterior coating. 
     
     
         9 . The fuel source according to  claim 1  having a calorific value of greater than 4,000 BTU/lb. 
     
     
         10 . The fuel source according to  claim 1  having a calorific value in the range 4,000 BTU/lb to 10,000 BTU/lb. 
     
     
         11 . A method for forming a combustible solid fuel source comprising:
 providing a base formed of a cellulosic or fibrous organic material;   compressing the base material to a density of at least 50 lbs/cu ft;   the compression being arranged to reduce the moisture content of the base material to less than 15%;   and contacting the base material with a combustible oil so as to cause the oil to be absorbed into the base material such that the content of oil is less than 50% by weight.   
     
     
         12 . The method according to  claim 11  wherein the oil content is less than 35%. 
     
     
         13 . The method according to  claim 11  wherein the oil content is substantially equal to 30%. 
     
     
         14 . The method according to  claim 11  wherein the density of the base material lies in the range 50 to 85 lbs/cu ft. 
     
     
         15 . The method according to  claim 11  wherein the quantity of oil is arranged such that the amount of oil is substantially the maximum which can be absorbed while such that the oil has no tendency to escape from the base material. 
     
     
         16 . The method according to  claim 11  wherein the oil is absorbed into the base material by dipping the base material into a bath of the oil leaving a top part of the base material exposed and by allowing the oil to wick to the top part of the base material. 
     
     
         17 . The method according to  claim 11  wherein the base material after compression is contacted by the oil substantially without the addition of heat to the base material. 
     
     
         18 . The method according to  claim 11  wherein the base material has a moisture content prior to compression of at least 25%. 
     
     
         19 . The method according to  claim 11  wherein moisture and oil are expelled from the base material during the compression.