Plant biomass solid fuel

Abstract

A solid fuel is formed in a cuber to form body pieces formed of materials extruded through a die with a density greater than 35 lbs/cu ft; an energy content greater than 6500 BTU/lb; transverse dimensions less than 1.5 inches; and a length less than 4 inches; from plant biomass material which contains components when extended of greater than 1.0 inch. Primarily the materials are paper or other cellulose product and crop residue such as wheat straw. The cellulose and lignin from these materials act without additional binders as binders and encasing materials. The moisture content is maintained at a target value by mixing selected quantities of the materials without drying. The cubing machine has a feeding system where the space between the inner rotor and outer casing is smaller than 4 inches and the height of the outer flight is less than 1 inch.

1 . A solid fuel material for combustion comprising:
 a series of body pieces each formed of compressed materials extruded through a die such that each body piece has a peripheral, longitudinally extending, outer surface with each body piece being severed from next adjacent body pieces to form two surfaces transverse to the peripheral surface;   each body piece having a density greater than 35 lbs/cu ft;   each body piece having an energy content greater than 6500 BTU/lb;   each body piece having dimensions in the transverse direction which are all less than 1.5 inches;   substantially all the body pieces having a length in the longitudinal direction between the transverse surfaces which is less than 4 inches;   wherein the compressed materials comprise plant biomass materials;   wherein the plant biomass material contains at least some components which have a dimension when extended of greater than 1.0 inch.   
   
   
       2 . The fuel material according to  claim 1  wherein the plant biomass material comprises a quantity of cellulose sufficient under heat and pressure to effect binding of the materials within the body pieces. 
   
   
       3 . The fuel material according to  claim 1  wherein the plant biomass material comprises a quantity of lignin sufficient to generate an exterior casing around the peripheral surface of polymerized lignin. 
   
   
       4 . The fuel material according to  claim 1  wherein body pieces each have a casing around the peripheral surface of polymerized lignin. 
   
   
       5 . The fuel material according to  claim 3  wherein the casing is arranged to apply containing forces to an interior of the body pieces. 
   
   
       6 . The fuel material according to  claim 1  wherein the compressed materials consist essentially of the plant biomass materials. 
   
   
       7 . The fuel material according to  claim 1  wherein each body piece has dimensions in the transverse direction which are less than 1.0 inches. 
   
   
       8 . The fuel material according to  claim 1  wherein each body piece is square in transverse cross section with a width of less than 1.0 inch. 
   
   
       9 . The fuel material according to  claim 1  wherein substantially all of the body pieces have a length less than 2 inches. 
   
   
       10 . The fuel material according to  claim 1  wherein the density lies in the range about 35 to about 55 lbs/cu ft. 
   
   
       11 . The fuel material according to  claim 1  wherein the thermal energy lies in the range about 6500 to about 8500 BTU/lb. 
   
   
       12 . The fuel material according to  claim 1  wherein the body pieces consist essentially of plant biomass material selected as an admixture arranged to provide a quantity of cellulose sufficient to effect binding under heat and pressure of the materials within the body pieces and to include a quantity of lignin sufficient to generate an exterior casing formed from polymerized lignin. 
   
   
       13 . The fuel material according to  claim 1  wherein the compressed materials contain at least 10% by weight of cellulose. 
   
   
       14 . The fuel material according to  claim 1  wherein the compressed materials contain 0.5 to 5% by weight of lignin. 
   
   
       15 . The fuel material according to  claim 1  wherein the body pieces contain binding agents provided essentially by the admixture of plant biomass material. 
   
   
       16 . The fuel material according to  claim 1  wherein the body pieces have a moisture content of 5 to 8%. 
   
   
       17 . The fuel material according to  claim 1  wherein the compressed materials produce a quantity of ash after complete combustion of less than 10%. 
   
   
       18 . The fuel material according to  claim 1  wherein the compressed materials produce a quantity of ash after complete combustion which contains less than 20% of Calcium, 20% of potassium and 75% silica. 
   
   
       19 . The fuel material according to  claim 1  wherein the plant biomass material contains at least some components which have a dimension when extended of greater than 4.0 inches. 
   
   
       20 . The fuel material according to  claim 1  wherein the plant biomass material contains comminuted components where the proportion of components having a dimension when extended of less 0.5 inches is less than 40%. 
   
   
       21 . The fuel material according to  claim 1  wherein the compressed materials consist essentially of wheat and/or barley straw and a material forming a refined cellulose. 
   
   
       22 . The fuel material according to  claim 1  wherein the compressed materials consist essentially of wheat and/or barley straw in the range 90% TO 50% and a material forming a refined cellulose in the range 50% TO 10%. 
   
   
       23 . The fuel material according to  claim 1  wherein the compressed materials consist essentially of flax shives and a material forming a refined cellulose. 
   
   
       24 . The fuel material according to  claim 1  wherein the compressed materials consist essentially of corn stover and a material forming a refined cellulose. 
   
   
       25 . The fuel material according to  claim 1  wherein the compressed materials consist essentially of crop residue and a material forming a refined cellulose. 
   
   
       26 . The fuel material according to  claim 1  wherein the compressed materials consist essentially of crop residue, wood and a material forming a refined cellulose. 
   
   
       27 . The fuel material according to  claim 1  which has combustion emissions containing less than 1% sulphur and substantially no heavy metals. 
   
   
       28 . The fuel material according to  claim 1  which is shaped and arranged to pass through an auger having a flight diameter of no greater than 5 inches. 
   
   
       29 . The fuel material according to  claim 21  wherein the material forming the refined cellulose is formed from steam exploded wheat and/or barley straw. 
   
   
       30 . The fuel material according to  claim 21  wherein the material forming the refined cellulose is paper.