Pelletizing process

Abstract

A method of making pellets is provided. The method may include grinding a biomass to a smaller particle size, forming a ground biomass. The ground biomass may then be placed within a conditioner and steamed for more than about 20 seconds, forming a steamed and ground biomass. The steamed and ground biomass may be formed into a plurality of pellets using a die having a larger open area.

What is claimed is: 
     
         1 . A method of forming pellets comprising:
 grinding a biomass to a smaller particle size forming a ground biomass;   steaming the ground biomass in a conditioner for more than about 20 seconds forming a steamed and ground biomass; and   pelletizing the steamed and ground biomass forming a plurality of pellets.   
     
     
         2 . The method of  claim 1 , wherein the biomass is ground to a particle size of about 4 mm to about 8 mm. 
     
     
         3 . The method of  claim 1 , wherein the biomass is ground to a particle size of about 5 mm to about 7 mm. 
     
     
         4 . The method of  claim 1 , wherein the biomass is ground to a particle size of 6 mm. 
     
     
         5 . The method of  claim 1 , wherein the biomass comprises a woody material. 
     
     
         6 . The method of  claim 1 , wherein the steam is delivered at a pressure of about 15 PSI to about 30 PSI. 
     
     
         7 . The method of  claim 1 , wherein the steaming raises the temperature of the biomass to about 150° F. and up to about 180° F. 
     
     
         8 . The method of  claim 1 , wherein the steaming of the ground biomass is for about 20 seconds and up to about 2 minutes. 
     
     
         9 . The method of  claim 1 , wherein the steaming of the ground biomass is for about 45 seconds and up to about 100 seconds. 
     
     
         10 . The method of  claim 1 , wherein the steaming of the ground biomass is for about 1 minute. 
     
     
         11 . The method of  claim 1 , wherein the steamed and ground biomass has a density of about 3 to about 4 pounds per cubic feet. 
     
     
         12 . The method of  claim 1 , wherein pelletizing the steamed and ground biomass comprises the step of compressing the steamed and ground biomass against a die comprising a plurality of openings forming an open area. 
     
     
         13 . The method of  claim 12 , wherein the open area ranges from about 35% to about 50% of the die. 
     
     
         14 . The method of  claim 1 , wherein the plurality of pellets each comprise a minimum bulk density of 40 lbs/cuft.