Methods and systems for processing cellulose-containing materials and isolating cellulose molecules; methods for regenerating cellulosic fibers

Abstract

Methods and systems of the present invention use cellulose-containing materials, which may include post-consumer waste garments, scrap fabric and/or various biomass materials as a raw feed material to produce isolated cellulose molecules having desirable properties that can be used in the textile and apparel industries, and in other industries. A multi-stage process is provided, in which cellulose-containing feed material is subjected to one or more pretreatment stages, followed by a pulping treatment, to isolate cellulose molecules. The isolated cellulose molecules may be used in a variety of downstream applications. In one application, isolated cellulose molecules are extruded to provide regenerated cellulose fibers having desirable (and selectable) properties that are usable in various industrial applications, including textile production.

We claim: 
     
         1 . A method for treating a cellulose-containing feedstock to isolate cellulose molecules comprising: subjecting the cellulose-containing feedstock to at least one pretreatment stage to produce cellulose-containing treated solids, wherein the at least one pretreatment stage is selected from the group consisting of: aqueous washing at a temperature above 100° C. and pressure in excess of 100 kPa; supercritical CO2 washing; amorphous phase aqueous treatment; treatment with oxidative and/or reducing agent(s); organic solvent treatment; enzymatic treatment; and treatment with swelling agents; and treating the cellulose-containing treated solids with a pulping agent to produce isolated cellulose molecules, wherein the pulping agent is selected from the group consisting of: a copper-containing pulping agent; an iron-containing pulping agent; and a zinc-containing pulping agent. 
     
     
         2 . The method according to  claim 1 , additionally comprising extruding the isolated cellulose molecules in a precipitation bath to produce regenerated cellulosic fibers. 
     
     
         3 . The method according to  claim 1 , wherein the pretreatment stage includes aqueous washing at a temperature above 100° C. and pressure in excess of 100 kPa in a close reaction vessel, and wherein the aqueous washing solution comprises at least one of the following additional agents: ozone; an oxidative agent; or a surfactant. 
     
     
         4 . The method according to  claim 1 , wherein the pretreatment stage includes supercritical CO2 washing in a closed reaction vessel, and the supercritical CO2 comprises at least one of the following additional agents: ozone; an oxidative agent; or a surfactant. 
     
     
         5 . The method according to  claim 1 , wherein the pretreatment stage includes treatment with aqueous solution at a temperature in excess of 320° C. at a pressure in excess of 2.5 Mps in a closed reaction vessel. 
     
     
         6 . The method according to  claim 1 , wherein the pretreatment stage includes treatment with an oxidative and/or reducing agent selected from the group consisting of: a peroxide composition; a perborate composition; a percarbonate composition; sodium carbonate; a per acetic acid composition; potassium permanganate; a persulfate composition; ozone; sodium chloride; calcium oxychloride, sodium hypochlorite; calcium hypochlorite; lithium hypochlorite; cloramine; isocynual trichloride; sulphur dioxide; sodium hydrosulfite; sulphoxylates; acidic sodium sulphite; sodium bosulphite; sodium meta bisulphite; TAED (tetra-acetyl-ethylene-diamine); and sodium hydrosulfite; and mixtures thereof. 
     
     
         7 . The method according to  claim 1 , wherein the pretreatment stage includes organic solvent treatment with an organic solvent selected from the group consisting of: acetic acid; acetone; acetonitrile; benzene; 1-butanol; 2-butanol; 2-butanone; t-butyl alcohol; carbon tetrachloride; chlorobenzene; chloroform; cyclohexane, 1,2-dichloroethane; diethylene glycol; diethyl ether; diglyme (diethylene glycol dimethyl ether); 1,2-dimethoxy-ethane (glyme, DME); dimethyl formamide (DMF); dimethyl sulfoxide (DMSO); 1,4-dioxane; ethanol, ethyl acetate; ethylene glycol; glycerin; heptane; hexamethylphosphoramide (HMPA); hexamethylphosphorous tramide (HMPT); hexane; methanol; methyl t-butyl ether (MTBE); methylene chloride; nitromethane; pentane; 1-propanol; 2-propanol; pyridine; tetrahydrofuran (THF); toluene; triethyl amine; o-xylene; and m-xylene; and mixtures thereof. 
     
     
         8 . The method according to  claim 1 , wherein the pretreatment stage includes enzymatic treatment by exposure to an enzyme selected from the group consisting of: endogluconases; Cel 5A; Cel 7B; Cel 12A; Cel 45; Cel 61A; Cellobiohydrolases; Cel 6A; Cel 7A; LPMO/GH61; and cellulases; and mixtures thereof. 
     
     
         9 . The method according to  claim 1 , wherein the pretreatment stage includes enzymatic treatment by exposure to an enzyme culture selected from the group consisting of:  Trichoderma Reesei, Trichoderma viride, Penicillium janthinellum, Halorhabdusutahensis, A Niger, Humicola;  and mixtures thereof. 
     
     
         10 . The method according to  claim 1 , wherein the pretreatment stage includes treatment with a swelling agent selected from the group consisting of: Ca, Mg, Na, K, and/or Li hydroxides; [AMIM]Cl 1-Allyl-3-methylimidazolium chloride; [BzPy]Cl Benzylpyridinium chloride; [BMIM]Ace 1-Butyl-3-methylimidazolium acesulphamate; [BMIM]DBP 1-Butyl-3-methylimidazolium dibutylphosphate; [BMIM]Cl 1-Butyl-3-methylimidazolium chloride; [BMIM]PF6 1-Butyl-3-methylimidazolium hexafluorophosphate; [BMIM]BF4 1-Butyl-3-methylimidazolium tetrafluoroborate; [BMPy]Cl 1-Butyl-3-methylpyridinium chloride; [DBNH]AcO 1,8-Diazabicyclo[5.4.0]undec-7-enium acetate; [DBNH]EtCOO 1,8-Diazabicyclo[5.4.0]undec-7-enium propionate; [DMIM]DEP 1,3-Dimethylimidazolium diethylphosphate; [DMIM]DMP 1,3-Dimethylimidazolium dimethylphosphate; [EMBy]DEP 1-Ethyl-3-methylbutylpyridinium diethylphosphate; [EMIM]AcO 1-Ethyl-3-methylimidazolium acetate; [EMIM]Br 1-Ethyl-3-methylimidazolium bromide; [EMIM]DBP 1-Ethyl-3-methylimidazolium dibutylphosphate; [EMIM]DEP 1-Ethyl-3-methylimidazolium diethylphosphate; [EMIM]DMP 1-Ethyl-3-methylimidazolium dimethylphosphate; [EMIM]MeSO4 1-Ethyl-3-methylimidazolium methanesulphonate; [HPy]Cl 1-Hexylpyridinium chloride; [E(OH)MIM]AcO 1-Hydroxyethyl-3-methylimidazolium acetate; [DBNMe]DMP 1-Methyl-1,8-diazabicyclo[5.4.0]undec-7-enium dimethylphosphate; [P4444]OH Tetrabutylphosphonium hydroxide; [TMGH]AcO 1,1,3,3-Tetramethylguanidinium acetate; [TMGH]n-PrCOO 1,1,3,3-Tetramethylguanidinium butyrate; [TMGH] COO 1,1,3,3-Tetramethylguanidinium formiate; [TMGH]EtCOO 1,1,3,3-Tetramethylguanidinium propionate; [P8881]AcO Trioctylmethylphosphonium acetate; and HEMA Tris-(2-hydroxyethyl)methylammonium methylsulphate; and mixtures thereof. 
     
     
         11 . The method according to  claim 1 , wherein the pulping agent is Schweitzer's Reagent. 
     
     
         12 . The method according to  claim 1 , wherein the pulping agent is an iron tartrate complex. 
     
     
         13 . The method according to  claim 1 , wherein the pulping agent is Zincoxen. 
     
     
         14 . The method according to  claim 1 , wherein treating the cellulose-containing treated solids with a pulping agent is carried out in a closed reaction vessel following evacuation of oxygen. 
     
     
         15 . The method according to  claim 1 , wherein treating the cellulose-containing treated solids with a pulping agent is carried out in a closed reaction vessel in the presence of an inert gas. 
     
     
         16 . The method according to  claim 1 , wherein the at least one pretreatment stage and the treatment with the pulping agent are carried out in a common closed reaction vessel.