Butanol from Biomass Klaus-Dieter Vorlop, Thomas Willke Johann Heinrich von Thünen-Institut Institute of Agricultural Technology and Biosystems Engineerging klaus.vorlop@vti.bund.de
Butanol market and properties Market Production (fossil), worldwide about 3 Mio. t/a (BASF 2009) about 5 Mio. t/a (DuPont 2007) Price: about 2 /kg Application currently almost completely for the chemical industry Properties (as fuel) Vapor pressure lower than that of ethanol Flash point higher than that of ethanol Mixable with diesel at all temperatures Better cold start properties as ethanol Water solubility is lower than of ethanol vti Vorlop page 1
n-butanol properties and production Properties and applications Solvent for laquers Solvent for TLC Base chemical (ethers, esters, cleaning agents, fuels) Production Historical: fermentation (molasses, potatoe, grain) currently: from crude oil Market volume: estimated 1,5. 5 Mio t/a (DuPont2007) Demand: 3.5 Mio. t (BASF2008) Price: 2,0 /kg (CCM 2009) 1-Butanol (butane-1-ol; n-butanol; butyl alcohol) Formula Molecular mass Density (20 C) Boiling point Melting Point Vapor pressure (20 C) Flash point Solubilitiy in water (20 C) Volumetric energy density Research Octane number (RON) C 4 H 10 O 74,12 g/mol 0,81 g/cm³ 117,7 C -89,5 C 5,6 hpa 35 37 C 77 g/liter ~ 29 MJ/L 96 vti Vorlop page 2
iso-butanol properties and production Properties and applications Solvent for laquers Base chemical (Ethers, Esters, cleaning agents, fuels) Production from crude oil In future? Fermentation (from syngas or residues) Enzymatic (from keto-acids, Genetic engineering) Market volume:??? Price:??? iso-butanol (2-methylpropane-1-ol, isobutyl alcohol) Formula Molecular mass Density (20 C) Boiling point Melting point Vapor pressure (20 C) Flash point Solubitiy in water (20 C) Volumetric energy density Research Octane number (RON) C 4 H 10 O 74,12 g/mol 0,80 g/cm³ 108 C -108 C 5,6 hpa 35 37 C 85 g/liter ~ 29 MJ/L > n-butanol vti Vorlop page 3
Butanol as Fuel properties Benzol Butanol Isobutanol Ethanol MTBE ETBE DMC DEC Mol.-weight [g/mol] 78 74 74 46 88 102 90 118 Density [kg/l] 0,88 0.81 0,81 0,79 0,74 0,74 1,07 0,98 Vapor pressure at 25 C [mm Hg] 95 7? 53 250 152 81 n.n. Oxygen content [weight-%] 0 22 22 35 18 16 53 41 Octane number* RON MON > 120 96 87 >96 129 92 116 101 118 102 125-131 100-109 110-112 95-103 *for comparison: RON/MON: Benzin 91/82.5 - Super 95/85 - Superplus 98/88 various sources, combined vti Vorlop page 4
Routes to Butanol from Biomass currently and in the future Sugar, starch, residues, biomass Fermentation Fermentation Catalysis Methanol Catalysis Butanol Catalysis Gasification Syngas Fermentation Catalysis Ethanol Whole crops, residiues Pyrolysis Pyrolysis oil Gas separation H 2 vti Vorlop page 5
Butanol-Synthesis by catalytic reaction: past and at present Route 1: Hydrogenation of crotonaldehyde (up to 1950) Ethanol Ethylene Butanol Route 2: Alcohol synthesis (Reppe 1942) Mild conditions (100 C, 10-15 bar) but expensive vti Vorlop page 6
Butanol-Synthesis by catalytic reaction: at present and prospective Route 3 : Oxo-synthesis (main process) Propylene Butyraldehyde Butanol Route 4: (Lassi 2009) Catalyst: Ni/Al 2 O 3, 250 C, non optimized Conversion: max 30% Selectivitity: 70% vti Vorlop page 7
Butanol-Synthesis ABE-fermentation (acetone, butanol, ethanol) Starch (grain, corn) 15-20% Acetone Residues ABE Fuel additive 70-80% Butanol 5-10% Ethanol Cellulose, Hemicellulose (wood, straw, etc.) vti Vorlop page 8 Fermentation Clostridium spp.
Butanol-Synthesis ABE-fermentation - fundamentals Microorganisms C. acetobutylicum C. beijerinckii C. saccharobutylicum C. saccharoperbutylacetonicum Metabolism Biphasic fermentation Acidogenesis (acid production) Solventogenesis (solvent production and sporulation) Products and yield ABE: 18-22 g/l (3:16:1) Butanol: 13-16 g/l Best results: ABE 33 g/l; Butanol 21 g/l (Qureshi & Blaschek 2001) Acidogenesis Solventogenesis Butanol vti Vorlop page 9
Butanol-Synthesis ABE-fermentation - problems High feedstock costs Low product concentration 13-16 g/l (best: 21 g/l) Product toxicity Butanol is more toxic than Ethanol Inhibition of growth (> 200 mm product) Liquefaction of membranes Brakedown of transport systems Unwanted byproducts Acetone 15 % Ethanol 5 % (Butanol 80 %) vti Vorlop page 10
Butanol (ABE) Fermentation performance and problems Recently Matured technology, extensive experience exist Potential use of residual biomass (also lignocellulosic, whey) High value byproducts (acetone, ethanol, H 2 ) usable Actual (batch) about 13/10 g/l butanol, max. 17 g/l, improvable Continuously: max. 10 g/l Butanol, productivity 6 g/l h, yield: 0,3 g/g Process optimization (feedstock, yield, productivity, down stream processing) currently in pilot scale Problems Low product concentration (due to inhibition) Low yield (byproducts) Process instability (cell degeneration, infection by phages) Complex and energy intensive down stream processing vti Vorlop page 11
Butanol-Production conventional process (since 1920) Batch-process: 200.000-800.000 L Ferm. time: 40 60 h Feedstock: corn mash, molasses Product concentration (total solvents): 12 20 g/l (corn) 18 20 g/l (molasses) Product separation: distillation Yield (total solvents) By theory: 38 % (w/w) 200.000 L Fermentation, Commercial Solvents Corp. realized: 25-26 % (corn), 29-33% (molasses) Productivity: 0,2-0,6 (g/l h) vti Vorlop page 12 Source: Bahl 2008
Butanol (ABE) Fermentation prospects Cost reduction Screening, mutation, genetic engineering Increase of product concentration Increase of butanol yield Utilization of low cost feedstock (residues, whole crops) Optimization of fermentation process Application of immobilized cells Continuously processes Application of integrated product separation (Butanol, Ethanol, Acetone, H 2 ) Extraction, membrane technologies vti Vorlop page 13
Butanol-Synthesis Example Immobilisates, continuously, 2-step-pilot plant, 150 L Gas 1. Acidification (butyrate) Clostridium thyrobutylicum Gas Down stream adsorption & desorption Gas condensor water sterile medium decanter recycle distillation valve Valve Valve Valve Butanol 10 L inoculum 1. step fermenter 40 L 10 L inoculum 2. step fermenter 150 L Butyl Fuel LCC vti Vorlop page 14 2. Alcohol production Clostridium acetobutylicum DOE Final Report (Ramey, Yang 2004)
Butanol-Fermentation (ABE) batch vs. continuous processes using immobilized cells Process Yield* [g/g] Productivity [g/l h] Products, total [g/l] Dillution-rate [1/h] Literature batch 0,28-0,33 ~1,5 ~ 20 A/B/E: 6/12/2 0,2 Qureshi & Blaschek, 2001 Immobilized cells thrickle-bed (foam) 0,34 4,2 16 0,27 Park et al., 1989 clay particle 0,38 16 7,9 2 Qureshi et al., 2000 fibrous bed FBB 0,43 8,6 10 0,9 Huang et al., 2005 * Butanol from Glucose (1mol/mol): 0,41 g/g (theoretical yield assuming 100%) vti Vorlop page 15
Butanol - Synthesis process integrated product separation stripping liquid-liquid extraction pervaporation vti Vorlop page 16 Lee et. al. Biotech Bioeng 2008
Butanol-Production in Russia biorefinery-concept (realized market routes) 45.000 t/a starch equivalent 90.000 t/a 4.100 t/a 8.550 t/a 2.300 t/a? vti Vorlop page 17 11 Mio m 3 /a? 13,1 Mio m 3 /a 8,7 Mio m 3 /a Zverlov et al., 2006
Butanol Production in China ABE-produktion plants (fermentation) vti Vorlop page 18
Butanol-Industrial Projects conventional process incl. genetic engineering 1 BP-Dupont (UK) Butamax -demonstration plant 2010, commercial from 2013 Cathey Industrial Biotech (China) 30,000 t plant in Jilin, in operation since 3/2008, upgrading to 200,000 t/a projected Cobalt Biofuels (USA) Continuously Patented vapor compression destillation separation Pilot plant since 1/2010 Butyl Fuel LCC (USA) Patented 2-step process via butyrate (thermophilic) vti Vorlop page 19
Butanol-Industrial Projects conventional process incl. genetic engineering 2 Tetra Vitae Bioscience (USA) Conventional technology New substrates Integrated down stream processing (new technologies) Arbor Fuel Inc (USA) Genetical modified yeasts Lignocellulosis feedstock Butalco (Switzerland) Genetical modified yeasts Butanol/Isobutanol from lignocellulose Metabolic Explorer (France) Genetic engineering, fermentation techniques Butanol fermentation from starch, sugar, lignocellulose vti Vorlop page 20
Butanol-Industrial Projects thermochemical via syngas Green Biologics (UK) Thermophilic pretreatment Product-tolerant strain (up to 4% Butanol-concentration) Utilisation of C5-sugar Syntec Biofuel (Canada): Isobutanol Thermochemical Versatile biomass spectrum Syngas Biofuels Energy (USA): Virtuelle Internet company (syngas portal) Thermochemical routes Syngas-biotechnology vti Vorlop page 21
Butanol-Industrial Projects butanol/isobutanol enzymatic from keto acids Gevo (USA) Isobutanol with E.coli (genetically modified) from keto acids Demonstration plant vti Vorlop page 22
Butanol vs. Ethanol fermentation and separation Substrates Mass yield, by theorie [g/kg GEQ*] realized [g/kg GEQ*] Product concentration [g/l] - Butanol (T B : 118 C) - Acetone (T B : 56 C) - Ethanol (T B : 78 C) - Water (T B : 100 C) Productivity [g/(l h)] Energy density [MJ/L] * GEQ: Glucose-Equivalent Butanol biomass, residues 0,38 0,33 12 18 ca. 4 ca. 1 970 980 0,2 1,2 29,2 Ethanol glucose sucrose 0,51 0,45 - - 80 120 880 920 1 5 19,6 vti Vorlop page 23 Various sources, combined
Conclusion Currently production costs are too high for using butanol as biofuel Using biobutanol as feedstock for chemicals is the preferred option Significant technological improvements are necessary before butanol can be used as biofuel vti Vorlop page 24
Thank you for your attention