Patent ID: 6193837
Filing Date: 2001-02-27
Classification: D21C,D21H

Abstract:
A process for producing a brightness stabilization mixture of water-soluble organic compounds from biomass pyrolysis oils, said mixture being useful to stabilize lignin-containing pulps and paper, comprising:a) reducing the size of biomass material, pyrolyzing said size-reduced biomass material in a fluidized bed reactor in the presence of an inert gas at temperatures between about 500.degree. C. to about 550.degree. C. and at a gas flow rate such that reactor residence time for pyrolysis products is less than about 0.4 to 0.6 seconds;b) separating a char/ash component from pyrolysis gasses and vapors while maintaining char-pot temperatures at about 400.degree. C. to avoid condensation of pyrolysis vapors;c) condensing pyrolysis gases and vapors, and recovering pyrolysis oils by mixing said pyrolysis oils with acetone to obtain an oil-acetone mixture;d) evaporating acetone and recovering pyrolysis oils;(e) extracting the recovered pyrolysis oils with water to obtain a water extract;(f) slurrying said water extract with activated carbon while stirring, and filtering said slurry to obtain a colorless filtrate solution having a pH of about 2.5-3.0;(g) stabilizing said filtrate solution against thermally-induced gelling and solidification by extraction with ethyl acetate to form an aqueous phase lower layer and an organic phase upper layer;(h) discarding said upper organic layer and extracting the aqueous layer of ethyl acetate, and discarding the ethyl acetate fraction to obtain a yellow-colored solution not susceptible to gelling or solidification upon heating;(i) heating the solution to distill off water and other light components and concentrating a bottoms fraction comprising hydroxyacetaldehyde and other non-volatile components having high boiling points; and(j) decolorizing the stabilized brown solution with activated carbon to obtain a brightness stabilization colorless solution containing water soluble organic compounds.