Carbon micro-plant
View Patent ↗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.
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.