Patent ID: 6846339

Claim:
A process for upgrading low rank carbonaceous material having a microporous structure and containing water comprising: providing a rotating roll type pelletizing mill including at least one roller and having at least two converging surfaces defining a nip therebetween, wherein at least one of said at least two surfaces is the surface of said at least one roller and is rollable in a direction toward said nip and further wherein tapered apertures are provided in one or more of said surfaces; feeding said low rank carbonaceous material to said nip where, by the rolling action of said at least one of said at least two surfaces, said low rank carbonaceous material is subjected to shearing stresses, causing attritioning of said microporous structure of said low rank carbonaceous material and the release of said water contained in said micropores; and continuing said attritioning until said low rank carbonaceous material forms into a plastic mass; extruding said attritioned low rank carbonaceous material either substantially immediately after or concurrently with said attritioning, by forcing said attritioned low rank carbonaceous material through the apertures by the rolling action of said at least one of said at least two surfaces, wherein said apertures have a decreasing diameter as said attritioned low rank carbonaceous material is pushed therethrough to thereby subject the attritioned low rank carbonaceous material to sufficiently high pressures to cause further mechanical release of water from said micropores and to promote renewed bonding between the particles of the low rank carbonaceous material; and forming said extruded low rank carbonaceous material into pellets.