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 biocarbon pellet comprising:
a solid biocarbon-containing material;
a polyphenolic material;
optionally, ash; and
optionally, water;
wherein the biocarbon pellet comprises no external binder other than the polyphenolic material;
wherein the weight ratio of the polyphenolic material to the solid biocarbon-containing material is from about 0.01 to about 5;
wherein the biocarbon pellet comprises from about 50 wt % to about 95 wt % fixed carbon; and
wherein the biocarbon pellet is characterized by a 24-hour water uptake of about 20 wt % or less, measured at 25° C. and 1 bar.
2 . The biocarbon pellet of claim 1 , wherein the biocarbon pellet comprises from at least about 60 wt % to at most about 90 wt % fixed carbon.
3 .- 4 . (canceled)
5 . The biocarbon pellet of claim 1 , wherein the polyphenolic material has a weight-average molecular weight from at least about 75 g/mol to at most about 50,000 g/mol.
6 . (canceled)
7 . The biocarbon pellet of claim 1 , wherein the polyphenolic material has a weight-average molecular weight from at least about 1,000 g/mol to at most about 50,000 g/mol.
8 . The biocarbon pellet of claim 1 , wherein the polyphenolic material has a viscosity at 25° C. from at least about 1 cP to at most about 1000 cP.
9 . (canceled)
10 . The biocarbon pellet of claim 1 , wherein the weight ratio of the polyphenolic material to the solid biocarbon-containing material is from at least about 0.05 to at most about 2.
11 . (canceled)
12 . The biocarbon pellet of claim 1 , wherein total carbon in the polyphenolic material is at least 90% renewable as determined from a measurement of the 14 C/ 12 C isotopic ratio of the total carbon in the polyphenolic material.
13 . (canceled)
14 . The biocarbon pellet of claim 1 , wherein the ash content of the biocarbon pellet is at most about 5 wt %.
15 . (canceled)
16 . The biocarbon pellet of claim 1 , wherein the moisture content of the biocarbon pellet is at most about 10 wt %.
17 .- 18 . (canceled)
19 . The biocarbon pellet of claim 1 , wherein the 24-hour water uptake of the biocarbon pellet is at most about 10 wt %, measured at 25° C. and 1 bar.
20 . (canceled)
21 . The biocarbon pellet of claim 1 , wherein the biocarbon pellet is characterized by a pellet compressive strength at 25° C. of at least about 100 lb f /in 2 .
22 . (canceled)
23 . The biocarbon pellet 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.
24 . (canceled)
25 . The biocarbon pellet of claim 1 , wherein the biocarbon pellet is characterized by a bulk density of at least about 40 lb/ft 3 .
26 . (canceled)
27 . The biocarbon pellet of claim 1 , wherein the biocarbon pellet has an enriched concentration of the polyphenolic material in an outer shell of the biocarbon pellet, and wherein the biocarbon pellet has an enriched concentration of the solid biocarbon-containing material in an inner core of the biocarbon pellet.
28 . The biocarbon pellet of claim 1 , wherein the biocarbon pellet further comprises wood fines.
29 . The biocarbon pellet of claim 1 , wherein total carbon in the biocarbon pellet is at least about 90% renewable as determined from a measurement of the 14 C/ 12 C isotopic ratio of the total carbon in the biocarbon pellet.
30 . The biocarbon pellet of claim 1 , wherein total carbon in the biocarbon pellet is essentially fully renewable as determined from a measurement of the 14 C/ 12 C isotopic ratio of the total carbon in the biocarbon pellet.
31 . The biocarbon pellet of claim 1 , wherein the biocarbon pellet is characterized by a pellet shape selected from the group consisting of sphere, cylinder, cube, octagon, hexagon, honeycomb, oval, column, bar, pillow, lentil, random granular, and combinations thereof.
32 . The biocarbon pellet of claim 1 , wherein the biocarbon pellet is characterized by a pellet size selected from at least about 1 mm to at most about 10 cm, calculated as effective diameter of the biocarbon pellet.
33 . The biocarbon pellet of claim 1 , wherein the biocarbon pellet is characterized by a low odor according to ASTM D1296.
34 . The biocarbon pellet of claim 1 , wherein the biocarbon pellet is characterized as non-self-heating when subjected to a self-heating test according to Manual of Tests and Criteria , Seventh revised edition 2019, United Nations, Page 375, 33.4.6 Test N.4: “Test method for self-heating substances”.
35 . The biocarbon pellet of claim 1 , wherein the biocarbon pellet is characterized by a parameter c selected from at least about 200 to at most about 1000, wherein c is given by:
χ
=
Fixed
Carbon
wt
.
%
H
2
O
Uptake
wt
.
%
×
Pellet
Density
in
lb
/
ft
3
36 . The biocarbon pellet of claim 35 , wherein c is selected from at least about 400 to at most about 1000.
37 . The biocarbon pellet of claim 35 , wherein c is selected from at least about 200 to at most about 800.
38 . The biocarbon pellet of claim 1 , wherein the biocarbon pellet is characterized by a parameter x selected from at least about 500 to at most about 5000, wherein x is given by:
ξ
=
Fixed
Carbon
wt
.
%
H
2
O
Uptake
wt
.
%
×
Pellet
Strength
in
lb
f
/
in
2
39 . The biocarbon pellet of claim 38 , wherein x is selected from at least about 800 to at most about 4000.
40 . The biocarbon pellet of claim 38 , wherein x is selected from at least about 1000 to at most about 2000.