System and method for preparation of solid biomass by torrefaction
First Claim
1. A torrefaction system comprising:
- a dryer configured to dry a relatively wet biomass fuel and provide a relatively dry biomass fuel;
a torrefaction reactor comprising;
an upper chamber configured to remove all moisture from the relatively dry biomass fuel in an environment containing steam, anda lower chamber configured to torrefy dried biomass produced by the upper chamber at a temperature between about 250°
C.-300°
C. (482°
F.-572°
F.);
a combustion unit configured to combust a portion of a gaseous mixture of steam and torrefaction gases vented by the torrefaction reactor to produce a flue gas; and
a heat exchanger configured to exchange heat from the flue gas to the gaseous mixture to provide a heated gaseous mixture for provision to the torrefaction reactor.
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Reexamination
Accused Products
Abstract
Methods and systems for preparing a torrefied biomass fuel are disclosed. Moisture is initially extracted from relatively wet biomass fuel to produce a relatively dry biomass fuel. Remaining moisture is then extracted from the relatively dry biomass fuel in a final drying stage, using steam at a temperature of about 900° F. The resulting dried biomass fuel is conveyed downward using gravity and undergoes torrefaction, which produces torrefied biomass fuel and torrefaction gases. A gaseous mixture of steam and torrefaction gases is vented to a heat exchanger, where the gaseous mixture is heated by a flue gas, and the heated gaseous mixture is used to support the extraction of the remaining moisture in the final drying stage and to support the torrefaction of the dried biomass fuel. Embodiments disclosed herein efficiently use available energy resources to the benefit of manufacturers, consumers, and the environment.
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Citations
7 Claims
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1. A torrefaction system comprising:
-
a dryer configured to dry a relatively wet biomass fuel and provide a relatively dry biomass fuel; a torrefaction reactor comprising; an upper chamber configured to remove all moisture from the relatively dry biomass fuel in an environment containing steam, and a lower chamber configured to torrefy dried biomass produced by the upper chamber at a temperature between about 250°
C.-300°
C. (482°
F.-572°
F.);a combustion unit configured to combust a portion of a gaseous mixture of steam and torrefaction gases vented by the torrefaction reactor to produce a flue gas; and a heat exchanger configured to exchange heat from the flue gas to the gaseous mixture to provide a heated gaseous mixture for provision to the torrefaction reactor. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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Specification