Patent ID: 8198493

Claim:
A process for treating biomass containing burnable organic constituents, comprising the steps of: thermally drying said biomass to a reduced moisture content in a dryer using the hot gas output of a fuel-operated burner assembly; thermally torrefying at least a portion of said dried biomass in an indirect torrefaction reactor different than said dryer using the hot gas output of said fuel-operated burner assembly to generate: (1) a first solid product output stream comprising hot torrefied biomass; (2) a first burnable gaseous output stream comprising a first portion of the burnable organic constituents evolved from said torrefaction of said biomass; and (3) a first residual gas stream from said torrefaction reactor comprising the gas used to indirectly torrefy said dried biomass; and carbonizing at least a portion of said hot torrefied biomass from said first solid product output stream in an indirect carbonization reactor different than said torrefaction reactor using a portion of the hot gas output of said burner assembly to generate: (1) a second solid product output stream comprising carbonized biomass; (2) a second burnable gaseous output stream comprising a second portion of the burnable organic constituents evolved from said carbonization of said torrefied biomass; and (3) a second residual gas stream from said carbonization reactor comprising the gas used to indirectly carbonize said torrefied biomass, said drying, torrefying, and carbonizing steps being carried out continuously.