Process for isolating cellulose from cellulosic biomass, isolated cellulose of type i and composite materials comprising same

Abstract

Described herein are processes for the production of a cellulose pulp and processes for isolating cellulose from cellulose-containing biomass. The processes of the invention comprises contacting the biomass with a source of anions and a source of cations, the source of anions and the source of cations being selected to react exothermically with the biomass and with each other. The processes of the invention have the particularity of generating exothermic reactions through enthalpies of reaction and mixture. Accordingly, the processes of the invention do not require any supply of external energy since the required energy is provided by chemical reagents that are already present in the biomass or added as needed. The invention also relates to isolated cellulose obtained from these processes and the use of same in various materials.

Description

RELATED APPLICATION[0001]The present application claims priority to Canadian patent application No. 2,803,863 filed Jan. 25, 2013, the content of which is incorporated herein by reference in its entirety.FIELD OF THE INVENTION[0002]The present invention relates to the field of biomass delignification and cellulose extraction. More particularly, the invention relates to processes for the production of a cellulose pulp and processes for isolating cellulose from cellulose-containing biomass. The invention further relates to isolated cellulose obtained from these processes and to the use of same in various materials.BACKGROUND OF THE INVENTION[0003]Plant biomass is primarily composed of cellulose (˜50%), lignin (˜25%) and hemicelluloses (˜25%).[0004]Although cellulose was first extracted using mechanical processes, nowadays cellulose is mostly obtained by chemical extraction processes, that were first developed on an industrial scale in Europe in 1850's. Those chemical processes general...

AI Technical Summary

Benefits of technology

[0036]An advantage of the present invention is that it provides relatively simpler, cheaper and more efficient means than all other chemical processes for making cellulose pulp and extracting cellulose from biomass. The processes of the invention can be implemented in variable sizes, such as large industrial facilities or smaller mobile units installed near or on the very sites of wood processing activities. The processes of the invention can be carried out at ambient pressure conditions and do not require external source of energy such as heating, pressurizing or the like. The chemical processes of the invention are likely more environmental friendly because they use less water and they produce less water and gas pollutants than other existing chemical processes. Furthermore, the cellulose that is obtained from these processes possess advantages in terms of purity (i.e. less lignin and less hemicelluloses), cell integrity, reactivity and abundance, than typical commercial type I and type II celluloses.

[0037]Additional aspects, advantages and features of the present invention will become more apparent upon reading of the following non-restrictive description of preferred embodiments which are exemplary and should not be interpreted as limiting the scope of the invention.

Problems solved by technology

Lignin is generally undesirable because of its adverse effect on paper, in particular as regards to its resistance and yellowing over time.

The Kraft process requires high heat and high pressure for several hours.

Both processes are highly polluting despite efforts since the 1930's to recover the chemical products used therein.

Chemical processes further require massive industrial facilities and huge investments to build and operate since these known processes require large amounts of energy and water and they must also deal with air and water pollutants.

All of these processes require however expensive equipment because of their use of high temperatures (between 95° C. and 270° C.) and pressure (between 3 and 40 bars).

In addition, these processes do not handle large volumes of material for industrial production, precisely because of the high cost of their facilities.

Although the method provides some advantages over the Kraft process, it still presents some disadvantages, including the need for thermal energy and the use of high pressure and the low yield of pure cellulose.

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