Potentials of higher alcoholes and oxygenates for engine application

Transcription

1 Potentials of higher alcoholes and oxygenates for engine application Florian Kremer Institute for Combustion Engines FNR Tagung Neue Biokraftstoffe 215

2 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

3 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

4 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

5 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

6 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

7 TMFB s fundamental first loop for the Diesel engine: That s why we want oxygenates! Smoke Number / FSN Low iso-octane/ n-heptane blends 1-decanol Influence cetane number new TMFB fuels 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

8 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 ~ Oxygen Content m-% Heating Value MJ/kg Boiling Range C Aromatics Content m-% ~ 25 Levulinic acid 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

9 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 Dodecanol Undecanol 1-Decanol 1-Nonanol Octanol Propanol 1-Hexanol 1-Pentanol 1-Butanol 1-Heptanol Ethanol Chain Length Cetane Data: NREL Compendium 9 von 21

10 Next TMFB loop: derivation of 1-Octanol as compromise between theoretical desired properties and application Unit Diesel EN59 1- Octanol Cetane Number Oxygen Content m-% Heating Value MJ/kg 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 Aromatics Content m-% ~ 25 Furfural Julis, Leitner: Angew. Chem. Int. Edt., 124 (34), , von 21

11 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 Displacement 39 cm³.4 3. Stroke / Bore 88.3 mm / 75 mm Compression Ratio Valves per Cylinder Max. Cylinder Pressure 22 bar Max. Injection Pressure 2 bar Injector Nozzle 8 x 153 Hydraulic Flow Rate 31 cm³/3s Heuser, Kremer et.al., SAE 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 11 von 21

12 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 Next 1 TMFB loop: 1-Octanol for 6 soot-free 1 combustion Engine Speed / rpm 1-Octanol EN59 Diesel 1.3 Heuser, Kremer et.al., SAE von Engine Speed / rpm Dr.-Ing. Dipl.-Wirt.Ing. Florian Kremer Institute for Combustion 35 Engines Engine Speed / rpm 1-Octanol EN59 Diesel 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

13 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

14 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 Amount Evaporated 25 C Amount Evaporated 35 C EN59 Limits % v/v ~1 < 65 % v/v ~1 > 85 Calorific Value MJ/kg Density (15 C) kg/m CN / DCN* - ~ 54 51** 39.1 > 51 Oxygen Content % m/m Vapor Pressure mbar <1 <1 <1 (,31) Kinematic Viscosity mm²/s 3 4.2** Enthalpy of Vaporization kj/kg *** 562 Flame Point C 78 79** 81 > 55 ** interpolated with 8/2 (Mass/Volume) *** interpolated 73/27 (molar quantities) 14 von 21

15 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 EU 6 NOx-levels 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 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 von 21 Dr.-Ing. Diesel Dipl.-Wirt.Ing. Florian Kremer Institute for Combustion Engines 8% Diesel / 2% Octanol

16 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!!! n = 228 min -1, p mi = 9.4 bar - 6 % Diesel 8% Diesel / 2% Octanol 5% Diesel / 5% Octanol Octanol n = 24 Dieselmin -1, p mi = 14.8 bar - 8% 3 % Diesel / 2% Octanol 5% Diesel / 5% Octanol Octanol 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!!!) von 21 Diesel Dr.-Ing. 8% Dipl.-Wirt.Ing. Diesel Florian / 2% Kremer Octanol Institute for Combustion Engines 5% Diesel / 5% Octanol

17 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

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19 Thank you for your attention! German Research Foundation WR Wissenschaftsrat