Organic biomass fractionation process

Abstract

A method for fractionating fibrous biomass comprising cellulose, hemicellulose and lignin components to separate said lignin, cellulose and hemicellulose from one another comprises: (a) shredding said fibrous biomass; (b) concurrently with or subsequent to said shredding, contacting said biomass with an aqueous solution of a nitrate ion source at a concentration of about 0.1-0.3% at a temperature in the range of about 60° to about 80° C. to initiate nitration of the lignin component of said biomass; (c) submerging said partially nitrated biomass in an aqueous solution of a nitrate ion source in the presence of an aluminum compound at a temperature within the range of about 75-100° C. for a time sufficient to complete the nitration of said lignin component; (d) contacting the nitrated biomass produced in step (c) with an alkaline extraction liquor comprising NH4OH at an initial concentration sufficient to solubilize said nitrated lignin component and said hemicellulose component from said cellulose component of said biomass; e) recovering said cellulose from said extraction liquor containing said solubilized nitrated lignin and hemicellulose components, wherein said cellulose comprises at least about 88% alpha cellulose; (f) treating said extraction liquor with an acid to precipitate lignin contained therein, and (g) separating said lignin from soluble hemicellulose in said extraction liquor. The recovered cellulose component comprises at least 88% alpha cellulose and is useful as a starting material for the production of ethanol.

Description

[0001] The present invention is directed to an economic method for fractionating renewable biomass safely to cleanly separate the cellulosic, hemicellulosic and lignin components of fibrous plant materials in a process without the concomitant production of by-products which could pollute water, land or air. The separated components are useful for the production of fossil fuel derivatives, biodegradable plastics, edible protein, and a variety of other products.[0002] The world today is facing growing burdens caused by overpopulation, depletion of fossil fuels, increasing demands for fuels, pollution of air, water and land, global warming and climate changes, forest cover destruction, and agricultural land loss. Although to some extent some of these concerns can be met through the improved use of solar energy and windpower and increased nuclear power, more conservation of resources and more efficient use of resources are always being sought.[0003] Fibrous cellulosic material, such as ...

AI Technical Summary

Benefits of technology

0006] Accordingly, it is an object of this invention to provide an economical and efficient method of fractionating a wide variety of renewable fibrous organic biomass

Problems solved by technology

The world today is facing growing burdens caused by overpopulation, depletion of fossil fuels, increasing demands for fuels, pollution of air, water and land, global warming and climate changes, forest cover destruction, and agricultural land loss.

To date, however, there has not been an economical method for cleanly separating the basic components of fibrous, ligno-cellulosic materials and the fermentable sugars they represent from one another.

In particular, it has proved difficult to economically separate the mixed hexose and pentose structured hemicellulose from the lignin and other, minor, co