Method and apparatus for producing biofuel

Abstract

The present invention relates to the field of renewable energy. More specifically, the present invention relates to the production of biofuel from biomass including, for example, polymeric materials.

1 . A method for producing a bio-oil, the method comprising:
 extruding polymeric material in an extruder to thereby form a melt stream comprising the polymeric material,   providing a stream of aqueous solvent that is separate to the melt stream,   contacting the melt stream with the stream of aqueous solvent to form a reaction mixture,   treating the reaction mixture in a reactor vessel at a reaction temperature and a reaction pressure for a time period suitable for conversion of all or a portion of the polymeric material present in the reaction mixture into a product comprising the bio-oil, and   depressurising and cooling the product.   
     
     
         2 . The method according to  claim 1 , wherein the extruder is a single screw extruder, a multiscrew extruder, a counter-rotating multiscrew extruder, a co-rotating multiscrew extruder, a twin screw extruder, a counter-rotating twin screw extruder, a co-rotating twin screw extruder, an intermeshing screw extruder, a radial extruder, or a roll-type extrusion press. 
     
     
         3 . The method according to  claim 1  or  claim 2 , wherein the method further comprises venting gases and/or vapours from one or a series of ports present in a barrel of the extruder. 
     
     
         4 . The method according to  claim 3 , wherein the gases and/or vapours comprise any one or more of: hydrogen chloride, hydrogen bromide, hydrogen fluoride, chlorine, ammonia, carbon monoxide, carbon dioxide. 
     
     
         5 . The method according to any one of  claims 1  to  4 , further comprising adding a base to any one or more of: the polymeric material prior to extrusion, the melt stream, the stream of aqueous solvent, and/or the reaction mixture, wherein:
 the base is an additional component to the polymeric material and the aqueous solvent, 
 within the reaction mixture the number of moles of the base added per 100 grams of polymeric material is between 0.5 times and 1.5 times the total number of moles of halogens per 100 grams of the polymeric material, and 
 the base precipitates metal halides in the reaction mixture facilitating their removal. 
 
     
     
         6 . The method according to  claim 5 , wherein the product has a pH of more than 3, 4, 5, 6, 7, 8, or 9 after cooling and depressurising it to ambient temperature and pressure. 
     
     
         7 . The method of any one of  claims 1  to  6 , wherein the melt stream exits from the extruder: 
       (i) at a pressure of more than 20 bar, more than 50 bar, more than 100 bar, more than 150 bar, more than 200 bar, more than 220 bar, more than 250 bar, or more than 350 bar, or between 220 bar and 300 bar; and/or 
       (ii) at a temperature of between 200° C. and 300° C. and a pressure of between 100 bar and 350 bar, or at a temperature of between 220° C. and 280° C. and a pressure of between 200 bar and 350 bar, or at a temperature of between 280° C. and 380° C. and a pressure of between 220 bar and 300 bar. 
     
     
         8 . The method of any one of  claims 1  to  7 , wherein the extruder is directly connected to a hydrothermal reactor apparatus in a manner allowing the melt stream to flow into the reactor in a continuous flow. 
     
     
         9 . The method according to any one of  claims 1  to  8 , wherein prior to said extruding the polymeric material is preteated using any one or more of grinding, chipping, pelletisation, granulisation, flaking, powdering, shredding, milling, compression/expansion, agitation, washing, flotation, removing materials comprising halogens optionally by infra-red or x-ray fluorescence detection and compressed gas classification/rejection and/or pulse-electric field (PEF) treatment. 
     
     
         10 . The method according to any one of  claims 1  to  9 , wherein the polymeric material is extruded in the presence of water, and the water constitutes less than 5 wt % (wet basis) of total polymeric material weight. 
     
     
         11 . The method according to any one of  claims 1  to  10 , wherein the polymeric material is selected from the group consisting of: Polyethylene (PE), Low Density Polyethylene (LDPE), High Density Polyethylene (HDPE), Polypropylene (PP), Polyester, Poly(ethylene terephthalate) (PET), poly(lactic acid) PLA, Poly (vinyl chloride) (PVC), Polystyrene (PS), Polyamide, Nylon, Nylon 6, Nylon 6,6, Acrylonitrile-Butadiene-Styrene (ABS), Poly(Ethylene vinyl alcohol) (E/VAL), Poly(Melamine formaldehyde) (MF), Poly(Phenol-formaldehyde) (PF), Epoxies, Polyacetal, (Acetal), Polyacrylates (Acrylic), Polyacrylonitrile (PAN), Polyamide-imide (PAI), Polyaryletherketone (PAEK), Polybutadiene (PBD), Polybutylene (PB), Polycarbonate (PC), Polydicyclopentadiene (PDCP), Polyketone (PK), polycondensate, Polyetheretherketone (PEEK), Polyetherimide (PEI), Polyethersulfone (PES), Polyethylenechlorinates, (PEC), Polyimide, (PI), Polymethylpentene (PMP), Poly(phenylene Oxide) (PPO), Polyphenylene Sulfide (PPS), Polyphthalamide, (PTA), Polysulfone (PSU), Polyurethane, (PU), Poly(vinylidene chloride) (PVDC), Poly(tetrafluoroethylene) PTFE, Poly(fluoroxy alkane) PFA, Poly(siloxanes), silicones, thermosplastics, thermosetting polymers, natural rubbers, tyre rubbers, ethylene propylene diene monomer rubbers EPDM, chloroprene rubbers, acrylonitrile butadiene (nitrile) rubbers, polyacrylate rubbers, Ethylene Acrylic rubbers, Styrene-butadiene rubbers, Polyester urethane rubbers, Polyether urethane rubbers, Fluorosilicone rubbers, silicone rubbers, and copolymers, synthetic polymeric materials, naturally-occurring polymeric materials, plastics, and mixtures thereof. 
     
     
         12 . The method according to any one of  claims 1  to  11 , wherein the reaction mixture prior to said treating comprises: 
       (i) at least 1 wt %, at least 2 wt %, at least 3 wt %, at least 4 wt %, at least 5 wt %, at least 10 wt %, at least 15 wt %, at least 20 wt %, at least 5 wt %, at least 30 wt %, at least 35 wt %, at least 40 wt %, at least 45 wt %, at least 50 wt %, at least 60 wt %, at least 70 wt %, at least 80 wt %, at least 90 wt %, at least 95 wt %, or at least 98 wt % of the polymeric material; and/or 
       (ii) less than 98 wt %, less than 95 wt %, less than 90 wt %, less than 80 wt %, less than 70 wt %, less than 60 wt %, less than 50 wt %, less than 45 wt %, less than 40 wt %, less than 35 wt %, less than 30 wt %, less than 25 wt %, less than 20 wt %, less than 15 wt %, less than 10 wt %, less than 5 wt %, less than 4 wt %, less than 3 wt %, less than 2 wt %, or less than 1 wt %, of the polymeric material. 
     
     
         13 . The method according to any one of  claims 1  to  12 , wherein the reaction mixture prior to said treating comprises:
 between 40 wt % and 80 wt % of the polymeric material from the melt stream and between 20 wt % and 60 wt % of the aqueous solvent from the aqueous solvent stream; or 
 between 50 wt % and 75 wt % of the polymeric material from the melt stream and between 25 wt % and 50 wt % of the aqueous solvent from the aqueous solvent stream. 
 
     
     
         14 . The method according to any one of  claims 1  to  13 , wherein the polymeric material comprises any one or more of:
 less than about 5 wt % nitrogen, less than about 1 wt % nitrogen, less than about 0.5 wt % nitrogen, or less than about 0.1 wt % nitrogen; 
 less than about 1 wt % total halogens, less than about 1 wt % total halogens, less than about 0.5 wt % total halogens, less than about 0.1 wt % total halogens, or less than about 0.05 wt % total halogens; 
 a molar ratio of hydrogen to carbon (H/C) of greater than 2.15, greater than 2.0, greater than 1.8, greater than 1.6, greater than 14, greater than 1.2, greater than 1.0, or greater than 0.8. 
 
     
     
         15 . The method according to any one of  claims 1  to  14 , wherein:
 the reaction temperature is or ranges between 300° C. and 600° C. and the reaction pressure is or ranges between 50 bar and 300 bar; or 
 the reaction temperature is or ranges between 350° C. and 550° C. and the reaction pressure is or ranges between 50 bar and 300 bar; or 
 the reaction temperature is or ranges between 350° C. and 600° C. and the reaction pressure is or ranges between 20 bar and 350 bar; or 
 the reaction temperature is or ranges between 375° C. and 550° C. and the reaction pressure is or ranges between 50 bar and 300 bar; or 
 the reaction temperature is or ranges between 400° C. and 600° C. and the reaction pressure is or ranges between 100 bar and 300 bar; or 
 the reaction temperature is or ranges between 380° C. and 500° C. and the reaction pressure is or ranges between 200 bar and 300 bar; or 
 
     
     
         16 . The method according to any one of  claims 1  to  15 , wherein the stream of aqueous solvent is supercritical prior to said contacting. 
     
     
         17 . The method of any one of  claims 1  to  16 , wherein prior to said contacting the stream of aqueous solvent comprises
 more than 90% supercritical water, more than 95% supercritical water, or 100% supercritical water; or 
 more than 90% subcritical water, more than 90% subcritical water, or 100% subcritical water; or 
 more than 90% steam, more than 95% steam, or 100% steam. 
 
     
     
         18 . The method of any one of  claims 1  to  17 , wherein prior to said contacting the stream of aqueous solvent comprises between 5 wt % and 40 wt % alcohol, between 1 wt % and 30 wt % alcohol, between 5 wt % and 25 wt % alcohol, between 1 wt % and 20 wt % alcohol, between 2 wt % and 20 wt % alcohol, between 1 wt % and 10 wt % alcohol, or between 2 wt % and 10 wt % alcohol. 
     
     
         19 . The method according to  claim 18  wherein the alcohol is ethanol, methanol, or a mixture comprising ethanol and methanol. 
     
     
         20 . The method according to any one of  claims 1  to  19 , wherein the method comprises
 separating one or more of a gaseous, aqueous, bio-oil, and/or wax component from the product, and/or 
 separating one or more fractions of a bio-oil, and/or one or more fractions of a wax component from the product. 
 
     
     
         21 . The method according to any one of  claims 1  to  20 , wherein the method comprises separating and recycling into the method one or more fractions of the product having a boiling point:
 between 30° C. and 140° C., between 60° C. and 160° C., 140° C. and 205° C., between 150° C. and 300° C., or between 230° C. and 350° C. 
 
     
     
         22 . The method according to any one of  claims 1  to  21 , wherein the method comprises separating and recycling into the method a fraction of the product comprising a wax or a waxy oil having a boiling point above 370° C. atmospheric equivalent boiling point (AEBP), above 400° C. AERP, above 450° C. AERP, above 500° C. AEBP, or above 550° C. AEBP. 
     
     
         23 . The method according to any one of  claims 1  to  22 , wherein the method comprises separating and recycling a fraction of the product having a boiling point in the range of a: naphtha boiling range, heavy naphtha boiling range, kerosene boiling range, diesel boiling range, heavy gas oil boiling range, or vacuum gas oil boiling range, and combusting the separated naphtha fraction to provide heat for repeating the method. 
     
     
         24 . The method according to any one of  claims 1  to  23 , wherein the reaction mixture comprises a supplementary catalyst selected from the group consisting of: a base catalyst, an acid catalyst, a water-gas-shift catalyst, an alumino-silicate catalyst, a sulphide catalyst, and any combination thereof, wherein the supplementary catalyst is not derived from any other component of the reaction mixture or a vessel wall of a reactor apparatus, and does not form in situ during the method. 
     
     
         25 . The method according to  claim 24 , wherein the supplementary catalyst is selected from the group consisting of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium formate, potassium formate, an iron salt, or any combination thereof. 
     
     
         26 . The method according to  claim 24  or  claim 25 , wherein the supplementary catalyst is added to the reaction mixture after the reaction mixture has reached said reaction temperature, or after the reaction mixture after the reaction mixture has reached said reaction temperature and said reaction pressure. 
     
     
         27 . The method according to any one of  claims 1  to  26 , wherein the reaction mixture comprises between 5 wt % and 60 wt %, between 10 wt % and 60 wt %, or between 20 wt % and 60 wt %, of oil, optionally wherein the oil is recycled from a bio-oil product previously generated in accordance with the method of any one of  claims 1  to  26 . 
     
     
         28 . The method according to  claim 27 , wherein the oil is selected from the group consisting of paraffinic oil, gas-oil, crude oil, synthetic oil, coal-oil, bio-oil, shale oil, kerogen oil, mineral oil, white mineral oil, and aromatic oil. 
     
     
         29 . The method according to any one of  claims 1  to  28 , wherein the reaction mixture prior to said treating: 
       (i) comprises less than 10 wt %, less than 5 wt %, less than 4 wt %, less than 3 wt %, less than 2 wt %, or less than 1 wt %, of: lignocellulosic matter, coal, coke, peat, kerogen, tar sand, oil shale, shale tar, asphalt, asphaltine, natural bitumen, or bituminous sand; or 
       (ii) does not comprise lignocellulosic matter, coal, coke, peat, kerogen, tar sand, oil shale, shale tar, asphalt, asphaltine, natural bitumen, or bituminous sand. 
     
     
         30 . The method according to  claim 29 , wherein said lignocellulosic material comprises more than 5 wt % lignin, more than 10 wt % lignin, more than 15 wt % lignin, more than 20 wt % lignin, more than 25 wt % lignin, more than 30 wt % lignin, more than 35 wt % lignin, more than 40 wt % lignin, more than 45 wt % lignin, or more than 50 wt % lignin.