Process and apparatus for making a densified torrefied fuel

Abstract

I claim a process for producing a superior fuel from biomass by first torrefying the biomass and then densifying it to make pellets, cubes or logs with the steps of: heating biomass to a temperature of 150-300 C and preferably to 200-280 C in a heating device, and densification of the resulting torrefied biomass in a device that compresses the hot biomass to make pellets, cubes or logs. The process can be partially or totally self heating by burning the gaseous products of torrefaction in the oven surrounding the torrefication apparatus. The energy required for size reduction after torrefaction is greatly reduced and the energy required for densification is also greatly reduced.

What is claimed is:  
     
         1 . A process for producing a superior fuel from biomass comprising the steps of: Heating the biomass to a temperature of 150-300 C and preferably to 200-280 C; and densification of the resulting torrefied biomass to form pellets, cubes or logs.  
     
     
         2 . A process for producing a superior fuel from biomass comprising the steps of: Drying the biomass, comminuting it to a size compatible with the method of densification, heating the biomass in an auger, fluidized bed or rotary kiln to a temperature of 150-300 C and preferably to 200-280 C; followed by densification of the biomass in a pellet mill, cuber or log maker to make pellets, cubes or logs.  
     
     
         3 . An apparatus to carry out the above process for producing a superior fuel from biomass by first torrefying the biomass in an auger furnace, fluidized bed or rotary kiln and then densifying it using a suitable densification device to make pellets, cubes or logs.  
     
     
         4 . An apparatus to carry out the above process by burning the products of torrefaction in an oven that then heats the torrefaction process, thus reducing or eliminating the need for external fuel.