Updated on April 30, Hydrothermal Conversion of Lignocellulosic Biomass to Biofuels and Valuable Chemicals

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1 Updated on April 30, 2012 Hydrothermal Conversion of Lignocellulosic Biomass to Biofuels and Valuable Chemicals

2 Hydrothermal Conversion HTC 101 Biomass Water Heating

3 Hydrothermal Conversion Pressure (MPa) Liquid Subcritical Fluids Temperature ( o C) Supercritical fluid Vapor phase At o C, 4-20MPa. water is still liquid. At this state, water can catalyze both acidic and basic reactions because self-dissociation of water to H+ and H- is enhanced. When the temperature of water is close to supercritical point (374 o C), the phase boundary between liquid and gas disappears, and then all reactions are enhanced by the homogenous media. Due to these special catalytic properties of hot water, biomass HTC to bio-oil calls a great interest, but still not well studied.

4 Phase Behavior of Water Pressure (MPa) V III I Solid VI VII Critical Point (374 o C) Liquid Vapor Triple Point Density (kg/m 3 ) Dielectric Constant (ε) Density Ionic Product (IP) IP ε Temperature (K) Temperature ( o C) Critical Point at 374 o C In the subcritical region, ionic reactions are enhanced, while in the supercritical region free radical reactions are enhanced.

5 Advantages of Hydrothermal Conversion of Lignocellulosic Biomass to biofuel Lignocellulosic biomass Most abundant feedstock Low cost feedstock compared, can be zero for waste biomass like wood residue, manure, etc. High yield crops (e.g. energy crops) identified Wet feedstock without predrying A thermochemical process that does not need to separate cellulose from lignin Can produces biogas and biooil depending on conditions

6 Comparison of HTC with other technologies Technologies Conditions Time Main Products Notes Aerobic treatment Ambient T and P > 20 days C 2, Nitrate, N 2 No bioenergy Anaerobic treatment Ambient T and P ~15 days CH 4, C 2 Slowly Gasification/pyrolyis 400~600 o C Several minutes CH4, H 2, C, C 2 Predrying required HTC 250 to 350 o C 0 to 60 min Bio-oil and CH 4 & H 2 Without predrying

7 Hydrothermal Conversion of Cattle Manure to Biofuels

8 Much cattle manure in Canada In Canada, cattle manure production: 0.5 million tons per day [1]. Meanwhile, more cattle manure is produced in per hectare land. Central ldman - Willow (AB) Upper Red Deer - Blindman (AB) Lower Bow - Crowfoot (AB) Headwaters Battle (AB) Lower ldman (AB) Lower Red Deer - Matzhiwin (AB) (kg/ha) Little Bow (AB) Central ldman - Belly (AB) Statistics Canada, Cattle Statistics,

9 Toxic gas---ammonia Air Pollution from Cattle Manure Greenhouse gases--- CH 4 & N 2 20% 4% 2% 4% N % (kt C2 eq) CH % Cattle manure Ammonia emission sources in Canada, 2005 (Environment Canada, Ammonia, 2009) Year CH4 and N2 emission from cattle manure in Canada. National Inventory Report, : Greenhouse Gas Sources and Sinks in Canada. Environment Canada,

10 Water pollution from cattle manure Pollutants---- Ammonia, Nitrate, and Phosphorus Water pollution---- Eutrophication [5] Cattle manure Ammonia Daniel, T. C.; Sharpley, A. N.; Lemunyon, J. L., Agriculture Phosphorus and Eutrophication: A Symposium verview. Journal of Environmental Quality 1998, 27: Nitrate Phosphorus Surface water Underground water Eutrophication

11 Soil pollution from cattle manure Soil pollution--- Acidification Ammonia Inorganic acid Ammonium salts [ (NH4)2S4 ] Rain Cattle manure (NH4)2S4 + 2 H2S4 + HN3 Soil Soil Breemen, N. V.; Burrough, P. A.; Velthorst, E. J.; Van Dobben, H. F.; Wit,T. D.; Ridder, T.; Reijnders, B. H. F. R., Soil Acidification from Atmospheric Ammonium Sulphate in Forest Canopy through Fall. Nature 1982, 299: Acidified soil

12 verall bjectives of the Research Program Cattle manure waste Hydrothermal conversion To produce bioenergy (biogas and bio-oil) To reduce pollution and odor Literatures have shown that swine manure, wood and grass can be converted to bio-oil by hydrothermal conversion (HTC) [7-8]. N report on cattle manure in public literature

13 verall Experimental Procedures Cattle manure Aqueous solutions 1.8 L reactor (260~340 o C) (275~320 o C) Glucose /Cellulose Aqueous solutions (with catalysts) 70 ml tubular reactor Gases Liquid products Solids Micro-GC Extraction Bio-oil Yields Compositions (H 2, C, C 2, <C 5 ) Yields Compositions GC/MS GC/FID 7

14 Hydrothermal Gasification of Cellulose and Cattle Manure Effects of Alkalinity and Phase Behaviour

15 Cellulose Cellulose (a polymer of glucose) is the most abundant biopolymer globally, accounting for 1.5 x tonnes of annually available biomass. (Klemm et al, 2005) Glucose (C 6 H 12 6 ) + 6C 6H 6 C H CH 6H 12H 6C H 12H Photosynthesis Steam Reforming

16 Hydrothermal Gasification Effects Alkali salts (Control ph) Catalysts Pt group metals (Steam Reforming) Physical effects Heating Speed Gas Yield Supercritical > Subcritical

17 Cellulose Decomposition D-Glucose - C 6 H 12 6 H H H LBVET H LBVET H H H H H H RA LD H Pathway I Erythrose - C 4 H 8 4 H H + H Glycolaldehyde - C 2 H 4 2 RA Glycolaldehyde - C 2 H 4 2 H H - : Alkali Catalyzed reaction H + : Acid Catalyzed reaction LD : Low density reaciton HD : High density reaction Formaldehyde - CH 2 H H H + Glycolic Acid - C 2 H 4 3 Formic Acid - CH 2 2 H Pathway II H - Acetaldehyde - C 2 H 4 Acetic Acid - C 2 H 4 2 H H H H H RA HD Dihydroxyacetone - C 3 H 6 3 H H H H H - -H 2 Pyruvaldehyde - C 3 H 4 2 H - +H 2 Lactic Acid - C 3 H 6 3 H H H - HD H + LD Acrylic Acid - C 3 H 4 2 H Propionic Acid - C 2 H 4 Glyceraldehyde - C 3 H 6 3 H H LBVET Levulinic Acid - C 5 H 8 3 H Formic Acid - CH H H H Fructose - C 6 H 12 6 H H H H HD -H 2 H + Pathway III H Furfural Alcohol (5-HMF) C 6 H 6 3 +H 2 H + H H + H H H 1,2,4 Benzenetriol - C 6 H 6 3 Formaldehyde - CH 2 Furfural - C 5 H 4 2

18 All Intermediates Not Equal 1.2 Grams Gasified Per Gram Feedstock Results by Knezivic et al (2009) show not all intermediates gasified as easily

19 Research bjectives and verview Determine effects of alkali salt (Na 2 C 3 ) concentration on the gasification of cellulose in the presence of a Platinum group metal Determine effect of headspace fraction on the hydrothermal gasification of cellulose in the presence of a Platinum group metal Effect of alkali and a Pt group metal on the hydrothermal gasification of a mixed biomass, cattle manure.

20 Experimental Setup I Two batch reactors were constructed from SS 316 tubing. The reactor volume was 69mL. Reactors heated by Muffle Furnace Gas composition determined by micro gas chromatography (micro-gc) Liquid phase composition determined by gas chromatography with a flame ionization detector (GC-FID)

21 Effects of Alkalinity with 5% Pt/Al 2 3 catalyst

22 Effects of Residence Time Sodium Carbonate (alkaline ph) increase both carbon dioxide and hydrogen production

23 Acetic Acid and Methane As more acetic acid was produced, increasing amounts of methane were found in the solution. Highest yields of acetic acid (and methane) were found in 0.1M sodium carbonate solution.

24 Liquid Phase Analysis Furfural Alcohol (12.3mM) Butyric Acid (1.8mM) Unknown (Area=305.4) 60,000 50,000 40,000 30,000 20,000 10, ,000 24,000 18,000 12,000 6, M Na 2 C 3 uv uv Unknown Intermediate (Area=806.9) Acetic Acid (0.36mM) Propionic Acid (0.21mM) Unknown Intermediate (Area ) Butyric Acid (0.3mM) n-caproic Acid (0.6mM) Lactic Acid (0.3mM) Acetic Acid (11.6 mm) Dihydroxyacetone (28.3mM) Lactic Acid (9.5 mm) 50 mm Na 2 C 3 25,000 20,000 15, ,000 40,000 30,000 20,000 10, Retention Time (minutes) uv 10,000 5, mm Na 2 C mm Na 2 C 3 uv Acetic Acid (1.5mM) Propoionic Acid (0.2mM) Butyric Acid (0.4mM) Dihydroxyacetone (77.4mM) Lactic Acid (4.3mM) Propionic Acid (2.1mM) Retention Time (minutes) M Na 2 C 3 More Furfural Alcohol (HMF) 500 mm Na 2 C 3 More Dihydroxyacetone and Lactic Acid

25 Alkalinity Effects with 5% Pt/Si 2 Similar but more variable results were obtained using a 5% Pt/Si2 catalyst.

26 Alkalinity Effects with 1% Pt/Al 2 3 With a higher loading of 1% Pt/Al23, carbon monoxide became an important product under low alkalinity.

27 Effect of Headspace Fraction As headspace fraction increased, hydrogen increased. Magnitude of increase was dampened when sodium carbonate was added.

28 Liquid Phase Analysis 1,400 1, ,000 15,000 12,000 9,000 6,000 3,000 Acetone Propionic Acid (0.33 mm) Unknown Intermediate Acetic Acid (2.8 mm) Butyric Acid (1.1 mm) Dihydroxyacetone (4mM) Lactic acid (0.65 mm) Levulinic Acid (0.13 mm) -1,400 HMF (1.67 mm) Acetone Lactic acid ( ND) Unknown Intermediate Acetic Acid (2.6 mm) Dihydroxyacetone (0.2 mm) HMF (0.1 mm) Propionic Acid (0.5 mm) Butyric Acid (0.7 mm) 0 100,000 80,000 60,000 40,000 20, Unknown Intermediate Acetic Acid (2.9 mm) Propionic Acid (0.6 mm) Butyric Acid (0.8 mm) Lactic acid (1.3 mm) Levulinic Acid (0.55 mm) HMF (21.0 mm) 80,000 70,000 60,000 50,000 40,000 30,000 20,000 10,000 0 Retention Time (min) Acetone Methanol Unknown Intermediate Acetic Acid (1.0 mm) Butyric Acid (0.59 mm) Lactic acid (1.36 mm) HMF (16.3 mm) % headspace fraction (5 ml slurry, 0 M Na 2 C 3 ) % headspace fraction (15 ml slurry, 0 M Na 2 C 3 ) 18 Retention Time (min) HMF suppressed as the headspace fraction increased At highest headspace fraction, butyric acid most abundant 63.8 % headspace fraction (25 ml slurry, 0 M Na 2 C 3 ) 49.3 % headspace fraction (35 ml slurry, 0 M Na 2 C 3 )

29 Experimental Setup II 1.8 L batch reactor (SS316), Parr Instrument Company Gas composition was analyzed by micro-gc To Fumehood Micro-GC (D) Condenser (C) C Tap Water Solenoid Valve A B Controller (A) Cooling Loop Reactor (B) D

30 Cattle Manure Test Results mmol gas/gram volatile manure Carbon Dioxide Carbon Monoxide Hydrogen No Catalyst NaH RuCl3 NaH and RuCl3 Catalytic Conditions Experiments with Cattle Manure show synergy between the RuCl 3 and the basic NaH catalysts

31 Discussion Effects of Alkalinity Three Distinct Regions of Alkalinity 1. Region I HMF suppression 2. Region II Change to Basic Solution ph 3. Region III Formation of Bicarbonates from Carbon Dioxide Peak in Hydrogen when using Pt/Si 2 catalyst occurred at higher alkalinity (200 mm as opposed to 75mM) Liquid Phase changes from HMF (0M Na 2 C 3 ), to lactic acid and dihydroxyacetone Methane likely to be related to the decarboxylation of acetic acid Significant interaction between RuCl 3 and NaH catalysts

32 Discussion Effects of Headspace Fraction Higher headspace fractions (vapour fractions) enhanced gas production, the effect was most significant without the addition of sodium carbonate In general, decreasing headspace fraction resulted in a decreased concentration of detected chemicals. Under the most successful conditions (92.8% headspace fraction, no Na 2 C 3 ), butyric acid relatively significant chemical in the liquid phase.

33 Conclusions More facile pathways for gasification available under high headspace fraction, without the addition of alkali salt sodium carbonate. Acetic Acid appears to be a likely source for produced Methane Decomposition of Cellulose through HMF produces little gas Decomposition pathway has large impact on gasification yield and composition

34 Hydrothermal Conversion of Cattle Manure to Biooil

35 Cattle manure Laboratory Procedure Liquid Products + water Extraction Evaporation CH 2 Cl 2 C 4 H 10 CHCl 3 Separation Bio-oil Bio-oil Bio-oil Comparison HTC reaction system (1.8L; 310 o C ;15min) Yields Heating values Structures

36 Effects of solvents on bio-oil yields Bio-oil yields (wt% of volatile content of cattle manure) C4H10 CHCl3 CH2Cl2 Solvents (Conditions: 125g of cattle manure, 500g of water, 0.5 mol of NaH, residence time of 15 min, and 0 psig initial pressure of C)

37 Elemental compositions (by mass) 100% 80% 60% 40% 20% 0% Effects of solvents on elemental compositions of bio-oil CH2Cl2 CHCl3 C4H10 Cattle manure N H C (Conditions: 125g of cattle manure, 500g of water, 0.5 mol of NaH, residence time of 15 min, and 0 psig initial pressure of C)

38 Effects of solvents on heating values of bio-oil Bio-oil Heating value Standard derivation ( MJ/kg) Bio-oil (extracted by CH 2 Cl 2 ) Bio-oil (extracted by CHCl 3 ) Bio-oil (extracted by C 4 H 10 ) Cattle manure

39 Effects of solvents on structures of bio-oil 5 4 C 4 H 10 Absorbance CH 2 Cl 2 CHCl Wavelength (nm) UV-VIS analysis spectra of bio-oil extracted by different solvents (Conditions: 125g of cattle manure, 500mL of water, 6g of NaH, process gas of 0 psig of C, and residence time of 15 min)

40 Effects of temperatures on bio-oil/bio-gas yields Bio-oil yields (wt% of volatile content of cattle manure) 50% 40% 30% 20% 10% 0% Bio-gas Bio-oil Bio-gas (millimole) Temperatures ( o C) (Conditions: 125g of cattle manure, 500g of water, 0.5 mol of NaH, residence time of 15 min, and 0 psig initial pressure of N 2 )

41 Effects of pressures on bio-oil yields 40% Bio-oil yields (wt% of volatile content of cattle manure) 30% 20% 10% 0% Pressure (psig) Figure 5. Effect of initial conversion pressure on biooil yield (Conditions: 125 g of cattle manure, 500 g of water, 0.5 mol of NaH, temperature of 310 o C, residence time of 15 min, and process gas of N2)

42 Effects of processing gases on bio-oil yields Bio-oil yields (wt% of volatile content of cattle manure) 60% 50% 40% 30% 20% 10% 0% 44.72% 48.76% 38.49% 27.97% Air N2 H2 C Processing gases Figure 6. Effect of process gasese on biooil yield (Conditions: 125g of cattle manure, 500g of water, 0.5 mol of NaH, temperature of 310 o C, and 0 psig process gas)

43 Effects of mass ratios of cattle manure to water on bio-oil yields Yields of bio-oil and residual solid (wt% of volatile content of cattle manure) 60% 2.00 Residual solids % Bio-oil 1.00 Bio-gas 20% % Total bio-gas (moles) Mass ratio of dry cattle manure to water Figure 7. Effect of cattle manure to water mass ratios on bio-oil yields (Conditions: T= 310 o C, 0.5 mol of NaH, residence time of 15 min, and 0 psig initial pressure of C)

44 Effects of processing gas

45 High heating values of bio-oils Energy types Heating value( MJ/kg) Bio-oil from HTC 290 o C o C o C o C Bio-ethanol 29.8 Coal 32.5 Gasohol E Bio-diesel 41

46 Bio-oil from cattle manure: Comparison with petro liquid fuels HTC bio-oil #87 Gasoline The main components of HTC bio-oil were carboxylic acids, aldehydes, and phenol derivatives. The main components of petroleum are alkanes. Fossil diesel Time (min) GC analysis of HTC bio-oil and fossil liquid fuels 9

47 Bio-oil from cattle manure: Stability The color of HTC bio-oil became darker with time. More residual solids were formed over time. Fresh bio-oil 1 day 1 week (It was stored at room temperature. HTC bio-oil was produced from cattle manure) During storage, the concentrations of aromatic chemicals and phenol derivatives decreased, while aldehydes and ketones increased. 10

48 Hydrothermal Conversion of Cellulose to Biooil

49 Bio-oil from cellulose ph=3 ph=7 No alkanes were detected in HTC bio-oil from cellulose. The compositions of HTC bio-oils varied with the initial ph levels of aqueous reaction media. ph=14 At ph<7: HMF and levulinic acid At ph=7: HMF, acetic acid and lactic acid At ph>7: Carboxylic acids Time (min) GC analysis of HTC bio-oils produced from cellulose at ph=3, 7 and 14

50 ph value changes vs. initial ph level Reaction pathways of HTC changed during alkaline HTC A Zone B Zone A B Cellulose Cellulose 13.5 Carboxylic acids Final ph<7 Weak alkaline solutions Carboxylic acids Final ph>7 Strong alkaline solutions Comparison of initial and final ph levels of alkaline HTC of cellulose to bio-oil Bio-oil: HMF+ carboxylic acids Bio-oil: carboxylic acids 12

51 Hydrothermal Conversion of Cellulose, Glucose to Alkanes

52 Motivation: Previous bio-oil from cattle manure or cellulose is not oil Compositions HTC bio-oil Acids, aldehyes, aromatic chemicals Catalytic HTC bio-oil Alkanes (Petroleum) Chemical stability Unstable Stable Separation rganic solvent extraction Voluntary separation from aqueous solutions Use as a liquid fuel Upgrading needed Directly used by car engine Need to improve the quality of HTC bio-oil by catalytic HTC 13

53 Alkanes from CHTC of glucose with hydrogen Alkane yields increased with increasing H 2 pressure. More heavy gaseous alkanes (C 3 H 8, C 4 H 10 ) were produced with higher H 2 pressure. The chemical composition was the same as that of liquefied petroleum gas (LPG) Alkane yields (%) 25% 20% 15% 10% 5% 0.5 g glucose, 3 g water, 0.5 g Pt/Al 2 3, 1.5 h reaction time and at 265 o C. Alkane (mmol) CH4 C3H8 C2H6 C4H10 0% Vacuum Vacuum Initial H 2 pressure (psi) Initial H 2 pressure (psi)

54 C 5-9 liquid alkanes were detected in liquid products 0.5 g glucose, 3 g water, 0.5 g Pt/Al 2 3, 265 o C, 1.5 h reaction time and initial 100 psi of H 2. GC analysis of C 5-9 alkanes in liquid phase But, much more C 1-4 alkanes were formed than C 5-9 alkanes.

55 Alkanes from CHTC of glucose (cont ) Problems with CHTC of glucose to alkanes Few liquid alkanes were formed from glucose. CHTC Gaseous alkanes (C< 5) Glucose (C6) External H 2 was required for CHTC. H 2 is required for hydrogenation reaction 16

56 Alkanes from CHTC of cellulose (cont.) A new reaction process was proposed to produce liquid alkanes from cellulose with in situ H 2 Steam reforming in situ H 2 Cellulose (a polymer of glucose) Alkane precursors (e.g. HMF) CHTC (Aqueous phase reforming-apr) Alkanes In-situ-H 2 -APR

57 Illustration of In-situ-H 2 -APR process Factor 1:v/v (water/reactor) Reactor N 2 Before conversion at room temperatures Heating the reactor During conversion at high temperatures (300 o C) Steam Factor 2: ph in situ H 2 produced by steam reforming of cellulose in steam phase. (catalyzed by ph>7) Water Cellulose (1) (2) Alkane precursors produced by CHTC of cellulose in liquid water phase. (catalyzed by ph<7) in situ H 2 + Alkane precursors (3) Alkane bio-oil (liquid alkanes)

58 Results: Alkanes from CHTC of cellulose Effects of volumetric ratios of input water to reactor Too little or too much water inhibited alkane bio-oil formation. The alkane bio-oil mainly consisted of nonane, octane and heptane. In-situ-H 2 -APR 3 g cellulose, 300 o C And 15 min reaction time Pyrolysis without water Conventional HTC using much water 19

59 Results: Alkanes from CHTC of cellulose Effects of ph levels of aqueous reaction media Alkane bio-oil yields were further increased by weak alkaline conditions. ph/reaction pathway changes mainly led to this improvement. ph=7.5 Initial ph>7 in situ H 2 (catalyzed by ph>7) Control: ph=7 Conversion Time ph=7 Final ph<7 Alkane precursors (catalyzed by ph<7) In-situ-H 2 -APR of cellulose to alkane bio-oil under weak alkaline conditions 20

60 Possible explanation to petroleum formation In-situ-H 2 -APR: a possible explanation for petroleum formation il Environment bservations Main components Associated with natural gas? Petroleum formed in sea alkanes Yes Bio-oil formed by In-situ-H 2 -APR alkanes Yes (syngas) Metals Ni, Fe, V, Cu Pt, Ni (catalysts) Inorganic chemicals Si 2 /Al 2 3 (the main components of earth crust) Si 2 /Al 2 3 (catalyst supports) ph (sea) 7.5 (aqueous media) Steam Geothermal heating External heating Liquid water Yes Yes

61 Conclusions 1. HTC bio-oil was different from petroleum, in terms of chemical composition. 2. HTC bio-oil compositions were unstable and changed with time. 3. But, by CHTC (especially, In-situ-H 2 -APR), alkane bio-oils were produced from glucose and cellulose. Their compositions are quite same as liquefied petroleum gas and gasoline, respectively. 4. Via catalytic HTC, therefore, a quick production of petroleum from renewable/carbon-neutral biomass would become feasible.

62 ther Slides

63 Biomass is Biological Material Derived from Living rganisms Recently Absorb C 2 and solar energy Three types of biomass: Lignocellulosic and starch-based plants (e.g. Wood, grass, livestock manure) Triglyceride-producing plants: e.g. canola, soybeans, sunflower, safflower Algae are another source of triglycerides as well as carbonhydrates and lignin. Miscanthus Jatropha Rapseed

64 Transportation Energy Needs to Remain Liquid to Fit in Existing Tanks and Be Transportable World has ~ 800 million vehicles, and adds 50 million vehicles per year Biomass is the only renewable source for renewable transportation fuel. Biofuel is the solution before electrical car becomes affordable and reliable. Biofuel may remain important since other sectors demands electricity rather than fuel.

65 Henry Ford originally designed the Ford Model T to run completely on ethanol. But then crude oil became more cheaply available.

66 Platforms for Biofuel Production [3] Gasification Pilot SynGas (C + H 2 ) Fischer-Tropsch Catalysis Fermentation FT diesel, Alkans, Jet fuel DMF, MtH, Mixedalcohol Ethanol Ligno cellulosic Biomass Pyrolysis and Liquefaction Pilot Hydrolysis Commercial Anaerobic Digestion Commercial Bioil (Including tars, acids, chars, alcohols, aldehydes, esters, ketones and aromatic) Sugar Glucose(C6), xylose(c5), sucrose and so on VFA (Acetate, propionate, Butyrate and so on ) Refining Fermentation Dehydration Fermentation Boiler oil, Diesel Ethanol, Butanol Furfural, MTHF, HMF Biogas (Methane) ily biomass Extraction Commercial Edible oil Transesterification Hydrotreating Biodiesel Renewable diesel Syngas and Sugar platform : two actively researched field for the liquid fuel

67 Canadian Renewable Fuels Association (CRFA) Canada

68 Challenges to existing biofuels Mostly from edible biomass High cost: 90% of $$$ goes to separation Mixed with petroleum gasoline Bio-oil Feedstock Pretreatment Use as liquid fuel Bio-ethanol Food crops Not required 1. Needing to be mixed with (e.g. Corn, wheat) petroleum before use 2. Not used in cold weather (low vapour pressure of ethanol) Bio-diesel Food crops (e.g. Canola oil) Predrying biomass 1. Not used in cold weather (gelling at low temperatures < -10 o C)

69 New Generation Biofuels: Cellulosic Feedstock Switchgrass Wheat Straw Hybrid Poplar Corn Stalks

70 Sustainable Production of Biofuels: An Integrated Biomass Production System C 2 H 2 Fuel Utilization Energy Nutrients C 2 H 2 Conversion Energy Non-edible C 2 H 2 Air Energy Transport Nutrients Separation Edible for feed and food