Process for producing high-carbon biogenic reagents
This invention provides processes and systems for converting biomass into high carbon biogenic reagents that are suitable for a variety of commercial applications. Some embodiments employ pyrolysis in the presence of an inert gas to generate hot pyrolyzed solids, condensable vapors, and non-condensable gases, followed by separation of vapors and gases, and cooling of the hot pyrolyzed solids in the presence of the inert gas. Additives may be introduced during processing or combined with the reagent, or both. The biogenic reagent may include at least 70 wt %, 80 wt %, 90 wt %, 95 wt %, or more total carbon on a dry basis. The biogenic reagent may have an energy content of at least 12,000 Btu/lb, 13,000 Btu/lb, 14,000 Btu/lb, or 14,500 Btu/lb on a dry basis. The biogenic reagent may be formed into fine powders, or structural objects. The structural objects may have a structure and/or strength that derive from the feedstock, heat rate, and additives.
1. A process for producing a high-carbon biogenic reagent, the process comprising:
providing a carbon-containing feedstock comprising dry biomass;
preheating, in a preheating zone, the feedstock in the presence of a substantially inert gas, thereby generating a preheated feedstock;
pyrolyzing, in a pyrolysis zone, the preheated feedstock in the presence of a substantially inert gas, thereby generating hot pyrolyzed solids, condensable vapors, and non-condensable gases;
separating at least a portion of the condensable vapors and at least a portion of the non-condensable gases from the hot pyrolyzed solids;
cooling, in a cooling zone, the hot pyrolyzed solids, in the presence of the substantially inert gas and with a cooling temperature less than the pyrolysis temperature, thereby generating warm pyrolyzed solids;
cooling, in a cooler that is separate from the cooling zone, the warm pyrolyzed solids, thereby generating cool pyrolyzed solids; and
recovering a high-carbon biogenic reagent, wherein the high-carbon biogenic reagent comprises at least a portion of the cool pyrolyzed solids;
wherein the process further comprises introducing at least one additive into the process.
2. The process of claim 1 , comprising drying the feedstock to remove at least a portion of moisture, if any, contained within the feedstock.
3. The process of claim 1 , comprising deaerating the feedstock to remove at least a portion of molecular oxygen contained with the feedstock.
4. The process of claim 1 , wherein the at least one additive is selected from acids, bases, or salts thereof.
5. The process of claim 1 , wherein the recovering comprises recovering a high-carbon biogenic reagent comprising at least 35% of the carbon comprised within the feedstock.
6. The process of claim 1 , wherein the recovering comprises recovering a high-carbon biogenic reagent comprising at least 70% of the carbon comprised within the feedstock.
7. The process of claim 6 , wherein the carbon comprises fixed carbon and carbon from volatile matter.
8. The process of claim 1 , wherein the high-carbon biogenic reagent has an energy content of at least 11,000 Btu/lb on a dry basis.
9. The process of claim 1 , comprising forming the high-carbon biogenic reagent into: a fine powder by particle-size reduction; a structural object by pressing, binding, pelletizing, or agglomeration; a structural object whose structure and/or strength are substantially derived from the feedstock, and/or is in substantially the same structural form as the feedstock.
10. The process of claim 1 , comprising preheating and wherein the preheating comprises preheating for at least 5 minutes and with a preheating temperature selected from about 80° C. to about 500° C.; wherein the pyrolyzing comprises pyrolyzing for at least 10 minutes and with a pyrolysis temperature of at least about 250° C.; or wherein the cooling comprises cooling for at least 5 minutes.