Blanket for pyrolysis or drying of biomass

Abstract

The disclosed embodiments are operable to produce biochar from a biomass or to dry a biomass through controlled heating. While prior art technologies are stationary enclosures, the embodiments provided herein are based on a portable, flexible laminated blanket that is draped over a biomass (e.g., a wood slash pile). In this way, the blanket functions as a portable and reusable kiln for pyrolyzing biomass into biochar or drying biomass.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows: 
     
         1 . A blanket comprising a material having the following properties:
 thermal insulation, such that the blanket is capable of withstanding temperatures of from 100 to 1000 degrees C.;   gas impermeability; and   flexibility, such that the blanket can be folded over on itself for storage;   wherein the blanket is configured to conformally cover a combusting biomass to facilitate pyrolysis or drying of the biomass.   
     
     
         2 . The blanket of  claim 1 , wherein the blanket consists of a single layer. 
     
     
         3 . The blanket of  claim 1 , wherein the blanket comprises two or more layers. 
     
     
         4 . The blanket of  claim 3 , wherein the blanket comprises a thermal insulation layer capable of withstanding temperatures of from 100 to 1000 degrees C.; and
 a gas impermeable layer that is a different material than the thermal insulation layer, wherein the thermal insulation layer is disposed closer to the combusting biomass than the gas impermeable layer.   
     
     
         5 . The blanket of  claim 3 , wherein the thermal insulation layer comprises a ceramic material. 
     
     
         6 . The blanket of  claim 5 , wherein the ceramic material is selected from the group consisting of ceramic pressed particulate paper and woven ceramic fibers. 
     
     
         7 . The blanket of  claim 3 , wherein the gas impermeable layer is a metal foil. 
     
     
         8 . The blanket of  claim 7 , wherein the metal foil is selected from the group consisting of stainless steel foil or other refractory metals and alloys foils from them. 
     
     
         9 . The blanket of  claim 1 , wherein the blanket has the additional property of durability, such that the blanket is not structurally damaged after repeated exposure to temperatures of from 100 to 1000 degrees C. 
     
     
         10 . The blanket of  claim 9 , wherein the blanket further comprises a first protective layer that confers the property of durability, wherein the first protective layer is disposed closest to the combusting biomass. 
     
     
         11 . The blanket of  claim 9 , wherein the first protective layer is a metal mesh layer. 
     
     
         12 . The blanket of  claim 9 , wherein the metal mesh layer is a stainless-steel mesh layer. 
     
     
         13 . The blanket of  claim 9 , wherein the blanket further comprises a second protective layer, disposed furthest from the combusting biomass. 
     
     
         14 . The blanket of  claim 1 , further comprising a plurality of air vents disposed peripherally on the blanket, wherein the plurality of air vents are configured to provide controllable air flow to pyrolyzing or drying biomass disposed beneath the blanket. 
     
     
         15 . A method, comprising the steps of:
 (a) combusting a biomass at a temperature sufficient to initiate pyrolysis or drying of the biomass;   (b) covering the biomass with the blanket of any one of  claims 1 - 14 , wherein the temperature of the biomass covered by the blanket can be controlled and is sufficient to pyrolize or dry the biomass, and wherein air from outside the blanket only reaches the biomass in a controlled manner; and   (c) maintaining the temperature of the biomass covered by the blanket for a sufficient time to produce biochar or dry biomass.   
     
     
         16 . The method of  claim 15 , wherein the biomass is pyrolized at a temperature of from about 200° C. to 650° C. 
     
     
         17 . The method of  claim 15 , wherein the biomass is dried at a temperature of from about 100° C. to 250° C. 
     
     
         18 . The method of  claim 15 , wherein the step of maintaining the temperature of the biomass covered by the blanket for a sufficient time to produce biochar or dry biomass comprises adjusting the amount of air flowing to the biomass at least once. 
     
     
         19 . The method of  claim 18 , wherein adjusting the amount of air flowing to the biomass comprises moving a peripheral edge of the blanket to increase or decrease airflow or operating peripheral vent ports. 
     
     
         20 . The method of  claim 15 , wherein air from outside the blanket only reaches the biomass by passing around the periphery of the blanket.