Energy efficient liquefaction of biomaterials by thermolysis

A process for the thermolysis of shredded biomass to produce combustible gas, vapour and aerosols similar in composition to gas, vapour and aerosols produced from fast pyrolysis, comprising:

• (a) introducing the biomass, shredded to a sufficiently small size so that its size does not limit significantly the production of combustible gas, vapour and aerosols, into a thermolysis reactor having a bed of inert material with a height to width ratio greater than one;
• (b) introducing substantially non-oxidizing gas upwardly through the bed at a linear velocity so as to cause automatic elutriation of product char and fluidizing of the bed of inert material to form a fluidized bed;
• (c) heating indirectly the fluidized bed so that the substantially non-oxidizing gas and fluidized bed have a temperature in the range of 360.degree. to 490.degree. C. and the substantially non-oxidizing gas and fluidized bed cause the thermolysis of the biomass producing an effluent reactor stream comprising hot char particles and volatiles, namely, gas, aerosols, and vapours;
• and
• (d) removing the elutriated char particles from the effluent reactor stream;
• (e) injecting the hot gas, aerosols and vapour from the reactor into a second combustion system where they are burned to produce heat;
• wherein the fluidized bed is sufficiently deep so that the residence time of the substantially non-oxidizing gas in the reactor is greater than 2 seconds.

Apparatus for thermolyzing shredded biomass particles to produce liquid similar in composition to liquid produced from fast pyrolysis, comprising:

• (a) a thermolysis reactor having a bed of inert material, a gas inlet at a bottom thereof for conducting non-oxidizing gas upwardly through said bed of inert material to form a fluidized bed, a transfer line at a top thereof for conducting away volatile effluent and char collection means for collecting char from the reactor;
• and
• (b) a combustor for burning gas and generating heated flue gas;
• and
• (c) a heat exchanger thermally coupled to said bed of inert material and to the heated flue gas from said combustor for heating the latter.