Carbon micro-plant

Abstract

The present disclosure provides biorefining systems for co-producing activated carbon along with primary products. A host plant converts a feedstock comprising biomass into primary products and carbon-containing co-products; a modular reactor system pyrolyzes and activates the co-products, to generate activated carbon and pyrolysis off-gas; and an oxidation unit oxidizes the pyrolysis off-gas, generating CO 2 , H 2 O, and energy. The energy is recycled and utilized in the host plant, and the CO 2 and H 2 O may be recycled to the reactor system as an activation agent. The host plant may be a saw mill, a pulp and paper plant, a corn wet or dry mill, a sugar production facility, or a food or beverage plant, for example. In some embodiments, the activated carbon is utilized at the host plant to purify one or more primary products, to purify water, to treat a liquid waste stream, and/or to treat a vapor waste stream.

What is claimed is: 
     
         1 . A method of retrofitting an existing biomass host plant, said method comprising:
 (i) installing a modular reactor system within or adjacent to an existing host plant that processes biomass, wherein said reactor system is capable of producing activated carbon;   (ii) conveying, to said reactor system, one or more carbon-containing co-products arising from operation of said host plant;   (iii) controlling said reactor system to pyrolyze and activate said one or more carbon-containing co-products, to generate activated carbon and pyrolysis off-gas; and   (iv) oxidizing said pyrolysis off-gas, to generate CO 2 , H 2 O, and energy,   wherein at least some of said energy is recycled and utilized in said host plant; and   wherein at least some of said CO 2  and/or H 2 O is recycled and utilized in said reactor system as an activation agent.   
     
     
         2 . The method of  claim 1 , wherein said host plant is selected from the group consisting of a saw mill, a pulp mill, a pulp and paper plant, a corn wet mill, a corn dry mill, a corn ethanol plant, a cellulosic ethanol plant, a sugarcane ethanol plant, a grain processing plant, a sugar production facility, a food plant, a nut processing facility, a fruit processing facility, a vegetable processing facility, a cereal processing facility, and a beverage production facility. 
     
     
         3 . The method of  claim 1 , wherein said biomass is selected from the group consisting of softwood chips, hardwood chips, timber harvesting residues, tree branches, tree stumps, leaves, bark, sawdust, corn, corn stover, wheat, wheat straw, rice, rice straw, sugarcane, sugarcane bagasse, sugarcane straw, energy cane, sugar beets, sugar beet pulp, sunflowers, sorghum, canola, algae, miscanthus, alfalfa, switchgrass, fruits, fruit shells, fruit stalks, fruit peels, fruit pits, vegetables, vegetable shells, vegetable stalks, vegetable peels, vegetable pits, grape pumice, almond shells, pecan shells, coconut shells, coffee grounds, food waste, commercial waste, grass pellets, hay pellets, wood pellets, cardboard, paper, paper pulp, paper packaging, paper trimmings, food packaging, lignin, animal manure, municipal solid waste, municipal sewage, and combinations thereof. 
     
     
         4 . The method of  claim 1 , wherein said one or more co-products are selected from the group consisting of wood waste, sawdust, fines, bark, distillers grains, residual solids from fermentation, lignocellulosic residues, lignin, carbon-containing ash, and combinations thereof. 
     
     
         5 . The method of  claim 1 , wherein said reactor system has a throughput capacity from about 10 ton/day to about 1000 ton/day on a dry basis. 
     
     
         6 . The method of  claim 5 , wherein said reactor system has a throughput capacity from about 50 ton/day to about 500 ton/day on a dry basis. 
     
     
         7 . The method of  claim 1 , wherein said reactor system is configured to carry out a continuous process for producing said activated carbon, said process comprising:
 (a) optionally drying said one or more co-products to remove at least a portion of moisture from said one or more co-products;   (b) in one or more indirectly heated reaction zones, mechanically countercurrently contacting said one or more co-products with a vapor stream comprising a substantially inert gas and an activation agent comprising at least one of water or carbon dioxide, to generate solids, condensable vapors, and non-condensable gases, wherein said condensable vapors and said non-condensable gases enter said vapor stream;   (c) removing at least a portion of said vapor stream from said reaction zone, to generate a separated vapor stream;   (d) recycling at least a portion of said separated vapor stream, or a thermally treated form thereof, to contact said one or more co-products prior to step (b) and/or to convey to a gas inlet of said reaction zone(s); and   (e) recovering at least a portion of said solids from said reaction zone(s) as activated carbon.   
     
     
         8 . The method of  claim 1 , wherein said oxidation unit has an energy-generation capacity from about 1 million Btu/hour to about 50 million Btu/hour. 
     
     
         9 . The method of  claim 8 , wherein said oxidation unit has an energy-generation capacity from about 10 million Btu/hour to about 20 million Btu/hour. 
     
     
         10 . The method of  claim 1 , wherein at least some of said energy is utilized for drying said feedstock, said one or more co-products, and/or a primary product from said host plant. 
     
     
         11 . The method of  claim 1 , wherein at least some of said energy is utilized for producing steam and/or electricity for use at said host plant. 
     
     
         12 . The method of  claim 1 , wherein at least some of said energy is recycled and utilized in said reactor system as activation heat. 
     
     
         13 . A method of distributing modular carbon micro-plants within a specified region of land, wherein said carbon micro-plants can convert carbonaceous co-products from host plants into activated carbon, said method comprising:
 (a) determining a plurality of sources of carbonaceous co-products from host plants within said region of land;   (b) determining a feedstock capacity and/or product capacity within said region of land;   (c) calculating, for said feedstock capacity and/or product capacity within said region of land, transportation distances to or from a plurality of possible sites, thereby generating a transportation profile within said region of land;   (d) selecting a total number of carbon micro-plants for said region of land, based on said feedstock capacity and/or said product capacity from step (b); and   (e) distributing said carbon micro-plants within said region of land based at least on information obtained in steps (a)-(d), using an optimization routine performed on a computer.   
     
     
         14 . The method of  claim 13 , wherein each carbon micro-plant comprises:
 a reactor system configured to pyrolyze and activate a carbonaceous co-product obtained from a host plant, to generate activated carbon and pyrolysis off-gas; and   an oxidation unit configured to oxidize said pyrolysis off-gas, to generate CO 2 , H 2 O, and energy,   wherein least some of said energy is integrated with said host plant; and   wherein at least some of said CO 2  and/or H 2 O is recycled and utilized in said reactor system as an activation agent.   
     
     
         15 . The method of  claim 13 , wherein each carbon micro-plant comprises a reactor system configured to carry out a continuous process for producing activated carbon, said process comprising:
 (a) optionally drying said one or more co-products to remove at least a portion of moisture from said one or more co-products;   (b) in one or more indirectly heated reaction zones, mechanically countercurrently contacting said one or more co-products with a vapor stream comprising a substantially inert gas and an activation agent comprising at least one of water or carbon dioxide, to generate solids, condensable vapors, and non-condensable gases, wherein said condensable vapors and said non-condensable gases enter said vapor stream;   (c) removing at least a portion of said vapor stream from said reaction zone, to generate a separated vapor stream;   (d) recycling at least a portion of said separated vapor stream, or a thermally treated form thereof, to contact said one or more co-products prior to step (b) and/or to convey to a gas inlet of said reaction zone(s); and   (e) recovering at least a portion of said solids from said reaction zone(s) as activated carbon.   
     
     
         16 . A computing system for distributing modular carbon micro-plants within a specified region of land, wherein said carbon micro-plants can convert carbonaceous co-products from host plants into activated carbon, said system comprising a computer having a processor, an area of main memory for executing program code under the direction of said processor, a storage device for storing data and program code and a bus connecting said processor, main memory, and said storage device; said code being stored in said storage device and executing in said main memory under the direction of said processor, to perform the steps of  claim 13 . 
     
     
         17 . The computing system of  claim 16 , said system further comprising a server computer linking said plurality of carbon micro-plants, wherein said server computer is capable of performing calculations and sending output data across a network. 
     
     
         18 . A network system comprising a spatially distributed plurality of modular carbon micro-plants for converting carbonaceous co-products from host plants into activated carbon, each carbon micro-plant comprising:
 a reactor system configured to pyrolyze and activate a carbonaceous co-product obtained from an individual host plant, to generate activated carbon and pyrolysis off-gas; and   an oxidation unit configured to oxidize said pyrolysis off-gas, to generate CO 2 , H 2 O, and energy,   wherein least some of said energy is integrated with said individual host plant; and   wherein at least some of said CO 2  and/or H 2 O is recycled and utilized in said reactor system as an activation agent.   
     
     
         19 . The network system of  claim 18 , wherein each carbon micro-plant comprises a reactor system configured to carry out a continuous process for producing activated carbon, said process comprising:
 (a) optionally drying said one or more co-products to remove at least a portion of moisture from said one or more co-products;   (b) in one or more indirectly heated reaction zones, mechanically countercurrently contacting said one or more co-products with a vapor stream comprising a substantially inert gas and an activation agent comprising at least one of water or carbon dioxide, to generate solids, condensable vapors, and non-condensable gases, wherein said condensable vapors and said non-condensable gases enter said vapor stream;   (c) removing at least a portion of said vapor stream from said reaction zone, to generate a separated vapor stream;   (d) recycling at least a portion of said separated vapor stream, or a thermally treated form thereof, to contact said one or more co-products prior to step (b) and/or to convey to a gas inlet of said reaction zone(s); and   (e) recovering at least a portion of said solids from said reaction zone(s) as activated carbon.