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.