Potentials of higher alcoholes and oxygenates for engine application Florian Kremer Institute for Combustion Engines FNR Tagung Neue Biokraftstoffe 215
AGENDA Short introduction and vision of TMFB Fuel Design: Why do we actually look at alcohols and oxygenates? Scientific Fuel Design to optimize fuel properties TMFB Diesel-type fuel candidate 2-MTHF: pros and cons TMFB Diesel-type fuel candidate 1-Octanol Drop-in/blending solutions Conclusion and outlook 2 von 21
TMFB Approach: The Vision of Tailor-Made Fuels from Biomass Model-Based Description of Synthesis and Production Routes From Biomass to Biofuels Fuel Design: Overall optimum of biofuel production and biofuel combustion From Biofuels to Propulsion Model-Based Specification of Target Properties 3 von 21
The Vision of Tailor-Made Fuels from Biomass: Efficient fuel production C-atoms 1 Biomass Preserving the Synthesis of Nature TMFB approach 1 Biomass-to-Liquid approach Tailor-Made Fuels defined oxygenates Fuel Substitutes hydrocarbon mixtures 1 Synthesis gas: CO/H 2 Exergy loss 4 von 21
From Biomass to Biofuels: Oxygenates are a feasible and sustainable option! Ligno-Cellulose Fractions Intermediates Fuels Carbohydrate Fractions to Intermediates Intermediates to Fuels Biomass Fractionation Lignin Conversion Feedstock Carbohydrate Fraction Intermediates Fuels 5 von 21
Fundamental research approach: High degree of freedom in the definition of new fuel candidates Density Molecular Structure Viscosity Compressibility Heating Value Surface Tension Burning Velocity Boiling Curve Heat of Vaporization Ignition Delay 6 von 21
TMFB s fundamental first loop for the Diesel engine: That s why we want oxygenates! Smoke Number / FSN 1.1.1 Low iso-octane/ n-heptane blends 1-decanol Influence cetane number new TMFB fuels.1 2 3 4 5 6 7 8 Cetane number / - Cetane Number Oxygen Content n-decane Influence of oxygen content High Desired Diesel type fuel properties: Reduced Cetane number Increased oxygen content Increased volatility Material compatibility and lubricating ability Volatility 7 von 21
Results from TMFB s first loop: 2-MTHF for soot free Diesel combustion Soot Emissions FSN CO Emissions / g/kwh HC Emissions / g/kwh CSL / db Unit Diesel EN59 2-MTHF 1. Diesel 2-MTHF 95 Cetane Number - 56.5 ~15.8.6 9 85 Oxygen Content m-%.14 18.6 Heating Value MJ/kg 42.9 33.5.4.2. 8 75 7 Boiling Range C 18-35 8 Aromatics Content m-% ~ 25 Levulinic acid 4 3 2 1 5 4 3 2 1 n = 15 min -1 IMEP = 4.3 bar n = 15 min -1 IMEP = 6.8 bar n = 228 min -1 IMEP = 9.4 bar n = 24 min -1 IMEP = 14.8 bar n = 15 min -1 IMEP = 4.3 bar n = 15 min -1 IMEP = 6.8 bar n = 228 min -1 IMEP = 9.4 bar n = 24 min -1 IMEP = 14.8 bar Soot reduction possible, but very low CN leads to high CO, HC and noise emissions 8 von 21
So a low Cetane number seems beneficial, but this property definition is limited: how would alcohols work? Cetane Number Oxygen Conten (mass fraction) 8 Alcohols.45 7 1-Dodecanol.4 6 5 1-Undecanol 1-Decanol 1-Nonanol.35.3 4 1-Octanol.25 3 2 1-Propanol 1-Hexanol 1-Pentanol 1-Butanol 1-Heptanol.2.15 1 Ethanol.1.5 1 2 3 4 5 6 7 8 9 1 11 12 13 Chain Length Cetane Data: NREL Compendium 9 von 21
Next TMFB loop: derivation of 1-Octanol as compromise between theoretical desired properties and application Unit Diesel EN59 1- Octanol Cetane Number - 56.5 39 Oxygen Content m-%.14 12.3 Heating Value MJ/kg 42.9 38.3 Single-pot, two step synthesis: 1-octanol and DOE in an excellent yield of 93 % Single-pot, three step procedure: The overall yield for C8-OL was 52% with a higher content of 1-octanol corresponding to a remarkable 33% yield of the free alcohol. Boiling Range C 18-35 195 Aromatics Content m-% ~ 25 Furfural Julis, Leitner: Angew. Chem. Int. Edt., 124 (34), 8743-8747, 212 1 von 21
CO Emissions / g/kwh CSL / db Soot Emissions FSN HC Emissions / g/kwh Next TMFB loop: 1-Octanol for soot-free combustion Unit.1 Diesel 1-Octanol 7.5 Emission benchmark Euro 6.8.6 6. 4.5 Displacement 39 cm³.4 3. Stroke / Bore 88.3 mm / 75 mm Compression Ratio 15.2. 2 1.5. 98 Valves per Cylinder 4 16 94 Max. Cylinder Pressure 22 bar 12 8 9 86 Max. Injection Pressure 2 bar Injector Nozzle 8 x 153 Hydraulic Flow Rate 31 cm³/3s Heuser, Kremer et.al., SAE 213-1-269 4 n = 15 min -1 IMEP = 4.3 bar n = 15 min -1 IMEP = 6.8 bar n = 228 min -1 IMEP = 9.4 bar n = 24 min -1 IMEP = 14.8 bar 82 78 n = 15 min -1 IMEP = 4.3 bar n = 15 min -1 IMEP = 6.8 bar n = 228 min -1 IMEP = 9.4 bar n = 24 min -1 IMEP = 14.8 bar 11 von 21
l. Air/Fuel Ratio (Spindt) / - Ind. Eff. / % CA5 / CA ABDC Ind. Spec. CO Rel. Air/Fuel Ratio Smoke (Spindt) number / - / - Ind. Eff. / % Exh. Gas Temp. / C Rel. Air/Fuel Ratio (Spindt) / - Ind. Eff. / % CA5 / CA ABDC Ind. Mean Eff. Press. / bar Ind. Spec. CO CSL / db CA5 / CA ABDC Ind. Spec. CO Smoke numb / - Exh. Gas Tem / C Smoke numb / - Exh. Gas Tem / C 3 8 3 8 2 Next 1 TMFB loop: 1-Octanol for 6 soot-free 1 combustion 7 2 7 6 2 3 5 2 1. 2 5 2 195 25 15 92.5 195 15 19 2 1 85. 19 1 185 15 5 77.5 185 5 18 1 7. 18 1.34 45 9 1.3 45 1.23 4 8 1.2 4 1.12 35 7 1.1 35 1.1 3 6 1. 3.9 2 195 19 1 2 3 4 Engine Speed / rpm 1-Octanol EN59 Diesel 1.3 Heuser, Kremer et.al., SAE 213-1-269 1.2 12 von 21 1.1 1. 1 2 3 4 Engine Speed / rpm 25 5 2 15 1 Dr.-Ing. Dipl.-Wirt.Ing. Florian Kremer Institute for Combustion 35 Engines 45 4 3.9 1 2 3 4 Engine Speed / rpm 1-Octanol EN59 Diesel 1 2 3 4 Engine Speed / rpm 185 At constant max. smoke higher load 5 possible (> 2.5 bar IMEP at 3 min -1 ) 18 At rated power and constant max. exhaust temperature remarkable soot reduction 25
The theoretical potential of 1-Octanol is proven: What about the application-related issues? Future fuel candidate Drop-in/blending Norming Infrastructure SCIENCE Legislation? APPLICATION 13 von 21
In an 8/2 blend of Diesel/1-Octanol, the EN59 targets can (nearly) be met! Unit EN59 Diesel 8%Diesel 2%1-Octanol 1-Octanol Boiling Range C 18-35 18-35 195 Amount Evaporated 25 C Amount Evaporated 35 C EN59 Limits % v/v 19.1 39.9 ~1 < 65 % v/v 94.7 95.8 ~1 > 85 Calorific Value MJ/kg 42.9 41.8 38.2 Density (15 C) kg/m 3 834 837 835 82-845 CN / DCN* - ~ 54 51** 39.1 > 51 Oxygen Content % m/m.14 2.9 12.3 Vapor Pressure mbar <1 <1 <1 (,31) Kinematic Viscosity mm²/s 3 4.2** 8.8 2 4.5 Enthalpy of Vaporization kj/kg 358 412*** 562 Flame Point C 78 79** 81 > 55 ** interpolated with 8/2 (Mass/Volume) *** interpolated 73/27 (molar quantities) 14 von 21
ISCO CSL / db ISPM ISHC ISCO CSL / db ISPM / mg/kwh ISHC ISCO / g/kw CSL / db 1 Low part load behavior of Diesel/1-Octanol blends 5 @ EU 6 NOx-levels 2. 1.5 1..5. 2 15 1 5.5.4.3.2.1. 8 6 4 2 n = 15 min -1, p mi = 4.3 bar n = 15 Diesel min -1, p mi = 6.8 bar 8% Diesel / 2% Octanol 5% Diesel / 5% Octanol Octanol 8 6 4 2 85 83 81 79 77 75 4 3 2 1 87 83 79 75 Diesel 8% Diesel / 2% Octanol 5% Diesel / 5% Octanol Octanol At lowest loads, the positive effect of the addition of 1-Octanol becomes visible at 5/5 blending rates Towards medium part-loads, the positive soot-reduction effect becomes active for the 8/2 blend already Apart from that, no remarkable difference in the emission formation tendency 81 79 77 75 15 von 21 Dr.-Ing. Diesel Dipl.-Wirt.Ing. Florian Kremer Institute for Combustion Engines 8% Diesel / 2% Octanol
ISCO CSL / db ISPM /g/kwh ISHC ISCO CSL / db ISPM ISHC ISCO / g/kw CSL / db 1 Higher part load behavior of Diesel/1-Octanol blends: 5 The non-linearity is on our side!!! 81 79 77 75.4.3.2.1 n = 228 min -1, p mi = 9.4 bar - 6 % 4 3 2 1 Diesel 8% Diesel / 2% Octanol 5% Diesel / 5% Octanol Octanol. 4 3 2 1.8.6.4.2. 4 3 2 1 n = 24 Dieselmin -1, p mi = 14.8 bar - 8% 3 % Diesel / 2% Octanol 5% Diesel / 5% Octanol Octanol 94 92 9 88 86.8.6.4.2. 89 88 87 86 At higher loads the positive trend of blending 1- Octanol becomes more articulated By blending 2% of 1-Octanol into EN59 Diesel fuel, soot reductions in the range of 3 6% can be achieved At the same time no increase in HC, CO nor combustion noise has to be taken into account (as it had been the case for 2- MTHF!!!) 85 16 von 21 Diesel Dr.-Ing. 8% Dipl.-Wirt.Ing. Diesel Florian / 2% Kremer Octanol Institute for Combustion Engines 5% Diesel / 5% Octanol
Conclusions and Outlook Using the interdisciplinary Fuel Design Approach Promising new fuel candidates can be identified 2-MTHF was found for a soot-free combustion but with disadvantages regarding HC- and CO-essmions 1-Octanol was identified as promising compromise (and promising alcohol alternative!) between emission reduction and usability (cold-start, Cetane number range) Applying these fundamental findings under real-life boundary conditions Drop-in solutions can be found that meet the existing norming standards A blend of 8/2 Diesel/1-Octanol was identified that over-represents the positive combustion properties of 1-Octanol: soot reduction up to 6% As next steps The production of 1-Octanol will be further optimized and possible scaled up First LCA/sustainability assessments will be done Vehicle dyno test are planned to prove the potential under normed boundary conditions 17 von 21
Thank you for your attention! German Research Foundation WR Wissenschaftsrat