Short Abstract for US Patent 5,735,916
UNITED STATES PATENT Patent Number: 5,735,916
Lucas et al. Date of Patent: Apr. 7, 1998

PROCESS FOR PRODUCTION OF LIGNIN FUEL, ETHYL ALCOHOL, CELLULOSE, SILICA/SILICATES, AND CELLULOSE DERIVATIES FROM PLANT BIOMASS

References Cited
U.S. Patent Documents

4,797,135 1/1989 Kubat et al.
5,114,541 5/1992 Bayer
5,186,722 2/1993 Cantrell et al.

ABSTRACT
This invention relates to a series of treatments, both physical and chemical, to plant biomass resulting in the production of ethanol, lignin, and a high protein animal feed supplement. In plants having a high silica content, a fourth product is obtained, silica/caustic oxide (silicates solution, waterglass.) Both 5-Carbon and 6-Carbon sugars are fermented to ethanol using an existing closed-loop fermentation system employing a genetically engineered thermophylic bacteria developed by Agrol, Ltd. The lignin and absolute ethanol are mixed producing a high-energy fuel.

5 Claims, No Drawings
PROCESS FOR PRODUCTION OF LIGNIN FUEL,
ETHYL ALCOHOL, CELLULOSE,
SILICA/SILICATES, AND CELLULOSE
DERIVATIVES FROM PLANT BIOMASS

This application is a continuation in part of application Ser. No. 08/460,493, filed Jul. 13, 1995, now abandoned.


FIELD OF THE INVENTIONThe invention relates to a method for producing lignin fuel (a mixture of lignin and ethyl alcohol), silica/sodium oxide, cellulose, and other cellulose derivatives from plant biomass.


BACKGROUND OF THE INVENTION
Description of Prior Art

The production of ethyl alcohol (ethanol) from 5-carbon and 6-carbon sugars has recently focused on the development of genetically engineered organisms. Prior to the work done in genetic engineering, considerable work was done with organisms, extraction of hydrolytic enzymes for cellulose and hemicellulose. B. S. Montencourt and D. E. Eveleigh, 1978, discussed producing fuels from plant biomass.

Delignification was done by Wilkes, et al., 1983 using chlorine dioxide/acetic acid solution.

Kubat et al, U.S. Pat. No. 4,797,135 describes a method of treating plant biomass with a weak caustic solution to produce a highly comminuted flour of wood and other vegetable biomass suitable for the use as fuel.

Many pretreatment technologies for the conversion of plant biomass, generally agricultural by-products (residues), have been developed in the past. The following institutions have provided work in plant biomass fuels:

The U.S. Army Natick Development Command, The University of California, Berkeley, Department of Engineering, The Lawrence Berkeley Laboratory, and The Indiana Institute of Technology (Spano, et al) The U.S. Pat No. 4,399,009 (Haig, 1981) claims the conversion of biological materials to liquid fuels. This patent uses zeolite catalysts to convert plant hydrocarbons with a molecular weight of over 150 into lower molecular weight entities for use as a liquid fuel. A gasoline fuel extender (methyltetrahydrofuran, MTHF) has been derived from plant biomass. MTHF, up to 10%, has been added to gasoline as a replacement for tetraethyl lead. Generally, the production of alternative fuels has centered on aromatic compounds and is therefore relatively expensive. A fuel derived from a mixture of ethyl alcohol (ethanol) and a lignin extract using a strong caustic solvent is an economically viable engine fuel.


REFERENCES CITED
The references cited within the text are incorporated to the extent they supplement, explain, provide background for, or teach methodology technology, and compositions employed herein.

Hagg, W.O., Rodewald, P.G. and Weisz, P.B., U.S. Pat. No. 4,3000,009, Nov. 10, 1981 A method of converting biological materials to liquid fuels.

Montencourt, B. S. and Eveleigh, D. E., Proceedings of Second Annual Symposium on Fuels from Biomass, Vol. II, p 613. Renssseleaer. Describes strains of bacteria and fungi having cellulose hydrolytic capabilities

Humphrey, A. E. and E. J. Nolan Report to the Office of Technology Assessment, Biological Production of Liquid Fuels and Chemical Feedstocks. Govt. Printing Office,

(The Detailed Description of the
Invention with “mass flow AND mass-energy balance are not included in this long abstract.)

We claim:
A method for producing lignin fuel, silica/sodium oxide, cellulose, and cellulose derivatives from plant biomass comprising the steps of placing the plant biomass in a hammermill or ball mill and grinding the plant biomass to 45 to 55 mesh, feeding the reduced size biomass into the first counter-current extractor, admixing the biomass with a mild acid solvent solution of acetic, carbonic, hydrochloric, phosphoric, or sulfuric acid at a temperature between 40 and 60 degrees C. and a residence time between 50 and 70 minutes, withdrawing a solvent stream from the first counter-current extractor containing 5-carbon sugars, soluble plant proteins, and soluble polypeptides which is passed to a fermentation tank where the 5-carbon sugars are fermented to ethanol,

withdrawing a solid material stream from the first counter-current extractor and passing the solid material through a belt-press filter, dewatering the solid material to between 70% and 80% total solids, and feeding the dewatered solid material stream into a second counter-current extractor, admixing the solid material with a caustic hydroxide solution, dissolving the lignin and silica,

withdrawing a solvent stream from the second counter-current extractor containing the lignin and caustic silicate and passing the solvent to an ultrafiltration membrane system, separating and concentrating the lignin from the solvent containing the caustic solution,

withdrawing from the ultrafiltration membrane unit a caustic silicate solution whereby a silica caustic oxide solution is produced,

withdrawing between 10% and 20% of the caustic silicate solution from the ultrafiltration membrane unit and sending the caustic silicate solution to the caustic solvent added to the second counter-current extractor as a feed-back solvent,

withdrawing the solid stream from the second counter-current extractor and passing the solid stream to a washing centrifuge and passing the solid to a belt-press filter dewatering the solid to 75% total solids,

withdrawing the solid from the belt-press filter and passing the solid to a tank wherein the solid cellulose material is converted to a glucose steam using acid hydrolyzing enzymes.