Method for extracting the chemical components from dissociated lignocellulosic material
AssigneeTigney Technology Inc.
InventorsEdward A. DeLong, Edward P. DeLong, George S. Ritchie, W. Alan Rendall
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Abstract
The chemical components of lignocellulosic material that have been dissociated by a stream explosion process can be extracted from the mixture of components using a solvent extraction process. The dissociated lignocellulosic material is put in a column and the substances which are soluble in water, alcohol and caustic are leached out of the mixture by solvent extraction with relatively small volumes of those solvents. No agitation is used. Substantially pure cellulose remains in the column and it can be bleached before removal from the column.
Claims13
A method of extracting chemical components from dissociated lignocellulosic material with small volumes of solvent comprising:
- (a) placing said dissociated lignocellulosic material to a predetermined height in a column having an upper opening and a lower opening;
- (b) adding water through said upper opening and, without agitating the contents of the column, permitting said water to percolate down through said dissociated lignocellulosic material in a plug flow and dissolve water-soluble substances;
- (c) removing said water and dissolved substances through said lower opening;
- (d) adding a suitably selected alcohol through said upper opening and, without agitating the contents of said column, allowing said alcohol to percolate down through said dissociated lignocellulosic material and dissolve alcohol-soluble substances;
- (e) removing said alcohol and dissolved substances through said lower opening;
- (f) adding a dilute aqueous caustic solution which will not swell the said dissociated lignocellulosic material sufficient to impede the flow of said caustic solution through said upper opening and, without agitating the contents of the column, permitting said caustic solution to percolate down through said dissociated lignocellulosic material in a plug flow and dissolve substances in said caustic solution;
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- (g) removing said caustic solution and dissolved substances through said lower opening;
- and wherein the said water, said alcohol and the said caustic solution are at a temperature of 65.degree. C. or less and a head of each is maintained during said adding steps (b), (d) and (f) such that the head is at least above the level of the said material in the column and the column is substantially unpressurized, and wherein no more than about 2 column volumes of said water, alcohol and caustic solution are used for said extractions.
Dependencies are inferred from the claim text.