Water-resistant and durable biocarbon pellets, and methods for making and using the same
Water-resistant, high-durability, and high-density biocarbon pellets are described. In some variations, a process for producing biocarbon pellets comprises: pyrolyzing a biomass-containing feedstock in a pyrolysis reactor, thereby generating a solid biocarbon-containing material and a pyrolysis vapor; introducing the pyrolysis vapor to a separation system configured to recover a pyrolysis condensate in liquid form separated from non-condensable gases; capturing pyrolysis condensate as a polyphenolic material; contacting the solid biocarbon-containing material with the polyphenolic material, thereby generating an intermediate mixture; introducing the intermediate mixture to a densification unit, thereby generating a biocarbon pellet precursor; and at least partially drying the biocarbon pellet precursor, thereby generating biocarbon pellets characterized by a 24-hour water uptake of about 20 wt % or less, measured at 25° C. and 1 bar. The biocarbon pellets can be stockpiled outside, which is logistically convenient at manufacturing sites, such as industrial metal-making plants that feed the biocarbon pellets into the process.
1 . A process for producing a biocarbon pellet, the process comprising:
pyrolyzing a biomass-containing feedstock in a pyrolysis reactor, thereby generating a solid biocarbon-containing material and a pyrolysis vapor, wherein the pyrolysis vapor comprises a polyphenolic material;
introducing the pyrolysis vapor to a thermally controlled multiple-stage separation system, thereby separating a pyrolysis condensate from non-condensable gases, wherein the pyrolysis condensate comprises the polyphenolic material;
capturing multiple liquid fractions, wherein the capturing is achieved utilizing the thermally controlled multiple-stage separation system, and wherein one of the multiple liquid fractions is the pyrolysis condensate comprising the polyphenolic material;
contacting the solid biocarbon-containing material with the polyphenolic material, thereby generating an intermediate mixture;
densifying the intermediate mixture in a densification unit, thereby generating a biocarbon pellet precursor; and
at least partially drying the biocarbon pellet precursor, thereby generating a biocarbon pellet;
wherein the biocarbon pellet is characterized by a 24-hour water uptake of at most about 20 wt %, measured at 25° C. and 1 bar; and
wherein the polyphenolic material is characterized by:
from about 20 wt % to about 80 wt % fixed carbon;
a weight-average molecular weight from about 75 g/mol to about 50,000 g/mol;
a viscosity at 25° C. from about 1 cP to about 1000 cP; and
from about 1 wt % to about 60 wt % water.
2 . The process of claim 1 , further comprising separating the solid biocarbon-containing material from the pyrolysis vapor, wherein the separating is achieved by utilizing a cyclone unit, and wherein the thermally controlled multiple-stage separation system comprises the cyclone unit.
3 . The process of claim 1 , further comprising exposing the pyrolysis vapor to water, thereby generating the pyrolysis condensate, wherein the exposing is achieved by utilizing a quench unit.
4 . The process of claim 1 , wherein the thermally controlled multiple-stage separation system further includes a demister unit configured to recover residual liquid from the gas stream.
5 . The process of claim 4 , further comprising combining the residual liquid with the pyrolysis condensate.
6 . The process of claim 1 , wherein the capturing comprises capturing the multiple liquid fractions according to molecular weight, boiling point, polarity, or a combination thereof.
7 . The process of claim 1 , wherein the intermediate mixture has a weight ratio of the polyphenolic material to the solid biocarbon-containing material selected from about 0.01 to about 5.
8 . The process of claim 1 , further comprising heating the polyphenolic material prior to contacting with the solid biocarbon-containing material.
9 . The process of claim 8 , wherein the polyphenolic material is heated to a temperature of at least about 150° C.
10 . The process of claim 1 , further comprising heating the solid biocarbon-containing material prior to contacting with the polyphenolic material.
11 . The process of claim 1 , further comprising bringing the solid biocarbon-containing material to a temperature within ±100° C. of the temperature of the pyrolysis reactor, prior to contacting with the polyphenolic material.
12 . The process of claim 1 , further comprising heating the intermediate mixture prior to the densifying.
13 . The process of claim 1 , further comprising operating the densification unit at a densification temperature of at least about 100° C.
14 . The process of claim 1 , the densifying comprises producing an enriched concentration of polyphenolic material in an outer shell of the biocarbon pellet precursor.
15 . The process of claim 1 , wherein the densifying and the drying are combined, and wherein the densification unit is also configured for the drying of the biocarbon pellet precursor.
16 . The process of claim 1 , wherein the biocarbon pellet is characterized by:
a moisture content from 0 wt % to about 10 wt % water;
a fixed-carbon content from about 50 wt % fixed carbon to about 99 wt % fixed carbon on a dry basis;
a 24-hour water uptake of at most about 10 wt %, measured at 25° C. and 1 bar; or
a pellet compressive strength at 25° C. of at least about 100 lb f /in 2 .
17 . The process of claim 1 , wherein the biocarbon pellet is characterized by a soaked/dried pellet compressive strength of at least about 100 lb f /in 2 , wherein the soaked/dried pellet compressive strength is measured by soaking the biocarbon pellet in water for 24 hours at 25° C., followed by drying the biocarbon pellet in air at 105° C. for 24 hours.
18 . The process of claim 1 , wherein the biocarbon pellet comprises no pellet binder other than the polyphenolic material.
19 . The process of claim 1 , further comprising pyrolyzing the biocarbon pellet, thereby increasing the fixed-carbon content of the biocarbon pellet.
20 . A process for producing a biocarbon pellet, the process comprising:
pyrolyzing a biomass-containing feedstock in a pyrolysis reactor, thereby generating a solid biocarbon-containing material and a pyrolysis vapor, wherein the pyrolysis vapor comprises a polyphenolic material;
introducing the pyrolysis vapor to a thermally controlled multiple-stage separation system, thereby separating a pyrolysis condensate from non-condensable gases, wherein the pyrolysis condensate comprises the polyphenolic material;
capturing multiple liquid fractions, wherein the capturing is achieved utilizing the thermally controlled multiple-stage separation system, and wherein one of the multiple liquid fractions is the pyrolysis condensate comprising the polyphenolic material;
densifying the solid biocarbon-containing material in a densification unit, thereby generating a first biocarbon pellet precursor;
contacting the polyphenolic material with the first biocarbon pellet precursor, thereby generating a second biocarbon pellet precursor; and
at least partially drying the second biocarbon pellet precursor, thereby generating a biocarbon pellet;
wherein the biocarbon pellet is characterized by a 24-hour water uptake of at most about 20 wt %, measured at 25° C. and 1 bar; and
wherein the polyphenolic material is characterized by:
from about 20 wt % to about 80 wt % fixed carbon;
a weight-average molecular weight from about 75 g/mol to about 50,000 g/mol;
a viscosity at 25° C. from about 1 cP to about 1000 cP; and
from about 1 wt % to about 60 wt % water.
21 . A process for producing a biocarbon pellet, the process comprising:
pyrolyzing a biomass-containing feedstock in a pyrolysis reactor, thereby generating a solid biocarbon-containing material and a pyrolysis vapor;
providing a polyphenolic material, wherein the polyphenolic material is characterized by:
from about 20 wt % to about 80 wt % fixed carbon;
a weight-average molecular weight from about 75 g/mol to about 50,000 g/mol;
a viscosity at 25° C. from about 1 cP to about 1000 cP; and
from about 1 wt % to about 60 wt % water;
contacting the solid biocarbon-containing material with the polyphenolic material, thereby generating an intermediate mixture;
densifying the intermediate mixture in a densification unit, thereby generating a biocarbon pellet precursor; and
at least partially drying the biocarbon pellet precursor, thereby generating a biocarbon pellet;
wherein the biocarbon pellet is characterized by a 24-hour water uptake of at most about 20 wt %, measured at 25° C. and 1 bar.
22 . The process of claim 21 , wherein the solid biocarbon-containing material is characterized by:
from about 65 wt % to about 95 wt % fixed carbon;
a weight-average molecular weight from about 75 g/mol to about 50,000 g/mol;
a viscosity at 25° C. from about 1 cP to about 1000 cP; or
from about 1 wt % to about 60 wt % water.
23 . The process of claim 21 , wherein the intermediate mixture has a weight ratio of the polyphenolic material to the solid biocarbon-containing material selected from about 0.01 to about 5.
24 . The process of claim 21 , wherein the densifying comprises operating the densification unit at a densification temperature of at least about 100° C.
25 . The process of claim 21 , wherein the densifying comprises producing an enriched concentration of polyphenolic material in an outer shell of the biocarbon pellet precursor.
26 . The process of claim 21 , wherein the densifying and the drying are combined, and wherein the densification unit is also configured for the drying of the biocarbon pellet precursor.
27 . The process of claim 21 , wherein the biocarbon pellet is characterized by:
a moisture content from 0 wt % to about 10 wt % water;
a moisture content from 0 wt % to about 5 wt % water;
a moisture content from 0 wt % to about 2 wt % water;
a fixed-carbon content from about 50 wt % fixed carbon to about 99 wt % fixed carbon on a dry basis;
a 24-hour water uptake of at most about 10 wt %, measured at 25° C. and 1 bar;
a pellet compressive strength at 25° C. of at least about 100 lb f /in 2 ; or
a bulk density of at least about 40 lb/ft 3 .
28 . The process of claim 21 , wherein the biocarbon pellet is characterized by a soaked/dried pellet compressive strength of at least about 100 lb f /in 2 , wherein the soaked/dried pellet compressive strength is measured by soaking the biocarbon pellet in water for 24 hours at 25° C., followed by drying the biocarbon pellet in air at 105° C. for 24 hours.
29 . The process of claim 21 , wherein the biocarbon pellet contains no pellet binder other than the polyphenolic material.
30 . The process of claim 21 , further comprising pyrolyzing the biocarbon pellet, thereby increasing the fixed-carbon content of the biocarbon pellet.
31 . A process for producing a biocarbon pellet, the process comprising:
pyrolyzing a biomass-containing feedstock in a pyrolysis reactor, thereby generating a solid biocarbon-containing material and a pyrolysis vapor;
providing a polyphenolic material, wherein the polyphenolic material is characterized by:
from about 20 wt % to about 80 wt % fixed carbon;
a weight-average molecular weight from about 75 g/mol to about 50,000 g/mol;
a viscosity at 25° C. from about 1 cP to about 1000 cP; and
from about 1 wt % to about 60 wt % water;
densifying the solid biocarbon-containing material in to a densification unit, thereby generating a first biocarbon pellet precursor;
contacting adding the polyphenolic material with to the first biocarbon pellet precursor, thereby generating a second biocarbon pellet precursor; and
at least partially drying the second biocarbon pellet precursor, thereby generating a biocarbon pellet;
wherein the biocarbon pellet is characterized by a 24-hour water uptake of at most about 20 wt %, measured at 25° C. and 1 bar.