Plantrose™: A Two Step Process
The water-based Plantrose™ Process consists of two core steps. The first is fractionation of biomass and separation of the remaining solids which contain cellulose and lignin. The second is cellulose hydrolysis of the pretreated solids under elevated conditions utilizing supercritical water, or water at higher temperatures and pressures, as the primary solvent. The relative ease of hydrolysis of the hemicelluloses compared to the recalcitrant cellulose necessitates this two-step process in order to preserve the C5 sugar that would be rapidly destroyed under the more severe conditions necessary for cellulose dissolution into C6 sugar.
The biomass first undergoes size reduction, as necessary, and is then conveyed to a storage silo. The stored solids are slurried with water and pumped and heated to reaction temperature and then fed to the fractionation reactor where the reaction takes place. The products from the fractionation reactor are then sent to solid/liquid filtration and stored.
The solids from the fractionation process consist predominantly of cellulose and lignin. These solids are sent to a blend tank where they are re-slurried by mixing with water and then pumped into the system at pressure and preheated. The preheated slurry is further treated with hot compressed water and undergoes a rapid reaction. The products from this reaction are then cooled and filtered. Remaining solids, in the form of clean, odorless, lignin, are collected.
Where necessary, the separate C5 and C6 soluble oligomer streams are easily and quickly transformed to monomers through a catalytic process. We have also developed processes to concentrate our sugars as necessary to meet the particular specifications of different partners.