SYNERGISTIC EFFECTS OF ALCOHOL- BASED RENEWABLE FUELS: FUEL PROPERTIES AND EMISSIONS by EKARONG SUKJIT School of Mechanical Engineering 1
Presentation layout 1. Rationality 2. Research aim 3. Research outline 4. Methodology 5. Results 6. Conclusions 2
Rationality. Why bioalcohols are needed? Environment concerns about emissions More stringent emission standards (THC, CO, NO x, PM) Use of energy from renewable sources 10% for bio-fuel consumption in the transport section before 2020 (2009/28/CE) Alcohols can participate as an alternative fuel for ICE Benefit of oxygen in fuel molecules (reduce soot formation) Contribution of biofuels (produce from crop, waste biomass, crude glycerol, algae etc.) Reduction in life-cycle green house emissions (lower C/H ratio, CO 2 required by production) Reduction in the dependence upon foreign oil in non-producing countries Used as fuel for vehicles (SI & CI engines) However the blending of alcohols is limited because of its low ignitability, lubricity, heating value and miscibility 3
European emission standards 0.15 (a) 0.4 (b) PM emissions (g/km) 0.12 0.09 0.06 0.03 Euro 1 (1992) Euro 2 (1996) Euro 3 (2000) Euro 4 (2005) Euro 5 (2009) Euro 6 (2014) PM emissions (g/kwh) 0.3 0.2 0.1 Euro I (1992) Euro II (1998) Euro III (2000) Euro IV (2005) Euro V (2008) Euro VI (2013) 0 0 0 0.2 0.4 0.6 0.8 1.0 NO X emissions (g/km) 0 2 4 6 8 10 NO X emissions (g/kwh) European emission standards for (a) diesel passenger cars (b) heavy-duty diesel engines 4
Rationality. Properties of alcohols Source: Lapuerta, M. (2010) 5
Rationality. Alcohol-diesel blends Stability Longer-chain alcohols (three or more carbon) shows better blending stability as a consequence of their higher polarity Source: Lapuerta, M. (2010) 6
Rationality. Alcohol-diesel blends Viscosity Source: Lapuerta, M. (2010) The limitation of viscosity for diesel fuel is 2-4.5 cst (40 o C) based on EN590 Percentage of alcohols blended with diesel is limited by viscosity limitation Ethanol: 22%, Propanol: 45%, Butanol and pentanol: No limitation 7
Rationality. Alcohol-diesel blends Lubricity The limitation of wear scar diameter generated by diesel lubricity test is 460 µm (60 o C) based on ISO 12156 Percentage of alcohols blended with diesel is limited by lubricity limitation Ethanol: 92%, Propanol: 80%, Butanol: 35%, Pentanol: 10% Source: Lapuerta, M. (2010) 8
Rationality. Why biodiesel is needed for alcoholdiesel blends? Alcohols/diesel blends need some additives to restore their properties such as blending stability, viscosity and lubricity. To meet this, biodiesel may be the alternative choice due to Miscibility in all ratios with diesel blends Good lubricity High viscosity Biodiesel refers to vegetable oil or animal fat consisting of long-chain alkyl esters of fatty acids Vegetable oil or animal fat + alcohols alkyl esters + glycerol Commonly methanol is used in tranesterification Most common fatty acid profile of biodiesel are palmatic acid (C16:0), stearic acid (C18:0), oleic acid (C18:1), linoleic acid (C18:2) and linolenic acid (C18:3) 9
Fatty acid profile of vegetable oil 10
Fatty acid profile of vegetable oil 11
Research aim To extend the use of alcohol-diesel blends through the biodiesel incorporation With objectives to study: Effect of biodiesel on fuel properties of diesel blends (emphasis on lubricity) Effect of molecular structure of biodiesel on alcohol-diesel blends Carbon chain length Unsaturation degree (double bond) Hydroxylation Effect of hydrogen on alcohol blends 12
Research outline Alcohol + Diesel Density Viscosity Miscibility Lubricity Biodiesel Low lubricity fuels ULSD GTL Lubricity test Biodiesel Improved lubricity Engine test Molecular structure Chain length Unsaturation C12:0 C14:0 C16:0 C18:0 C18:0 C18:1 Hydroxylation Improved soot-nox trade off C18:1 C18:1OH Carbonaceous gas emissions (HC & CO) from alcohol-dieselbiodiesel are higher with respect to pure biodiesel combustion Hydrogen No carbon atom High flame speed Improved HC, CO and soot Not compatible with diesel fuel specifications Chapter 4 Chapter 5 Chapter 6 Chapter 7 Rationality 13
Test fuels 14
Test fuels 15
Methodology. Lubricity test Modified HFRR (account for fuel evaporation) Deeper fuel holder Covered with a close-fitting PTFE lid Fretting flexure lock LVDT and flexure housing Electromagnetic vibrator PTFE seal set Upper specimen Fuel Counterweight Lower specimen Vibrator support extension Heater block Main RTD location hole (In far side of block) Force transducer 16
Methodology. Engine test Single cylinder diesel engine Engine specification Number of cylinders 1 Bore (mm) 98.4 Stroke (mm) 101.6 Connecting rod length (mm) 165 Displacement volume (cm 3 ) 773 Maximum torque (N.m) @ 1800rpm 39.2 Maximum power (kw) @ 2500 rpm 836 Compression ratio 15.5:1 Injection timing ( o btdc) 22 Maximum injection pressure (bar) 180 Injection system Three holes pumpline-nozzle Engine piston Bowl-in-piston Engine operating conditions Load: 3 and 5 bar IMEP Speed: 1500 rpm EGR: 0, 10% and 20% 17
Methodology. Experimental Installation Fresh air inlet Fuel injector Intake manifold Exhaust manifold Emission analysers EGR valve Exhaust gas out 1-Cylinder diesel engine Electric dynamometer Shaft encoder Wiring box NI PCI-MIO 16E-4 KISTLER 5011 Charge amplifier KISTLER 6125B Pressure transducer 18
Methodology. Emission analyser Horiba MEXA 7100DEGR (HC, CO, NOx) 19
Methodology. Emission analyser Horiba MEXA 1230 (Soot, SOM) 20
Methodology. Emission analyser Scanning Mobility Particle Sizer (PM distribution) 21
Methodology. Emission analyser ThermalGravimetric Analysis (PM composition: VOM, soot oxidation temperature) Filter Holding Plate Filter Stopper Loaded Filter Sample Filter Sample 22
Results 23
Heat release analysis Rate of heat release (J/CAD) 50 40 30 20 10 0-10 Ignition delay Premixed Combustion Diffusion Combustion Late Combustion SOI SOC EOI EOC -20-10 0 10 20 30 Crank angle degree (CAD) 24
Results. Biodiesel as lubricity enhancer Upper specimen Microscope WSD Lower specimen SEM & EDS Profilometer Lubrication film concentration Friction coefficient Microscopic topography Wear scar profile 25
Results. ULSD-RME blends Corrected wear scar diameter (µm) 300 274 250 200 219 214 217 211 208 200 206 206 204 188 150 100 0 10 20 30 40 50 60 70 80 90 100 RME (% v/v) 26
Results. GTL-RME blends Corrected wear scar diameter (µm) 350 300 290 250 200 196 202 203 214 211 205 216 212 217 204 150 100 0 10 20 30 40 50 60 70 80 90 100 RME (% v/v) 27
Results. Biodiesel as lubricity enhancer Carbon content (%) Low lubricity fuels Fixed 70% GTL + ULSD + RME ULSD GTL HFRR Profilometer G70D Biodiesel (RME) G70D20R ULSD GTL RME SEM & EDS G70D10R 20 15 10 5 D70G20R G70D20R 0 ULSD GTL RME D70G20R G70D20R 28
Results. Effect of molecular structure of biodiesel on alcohol-diesel blends: carbon chain length & unsaturation degree Lubricity test E10D B16D E10R15D B16R15D 29
Results. Effect of molecular structure of biodiesel on alcohol-diesel blends: carbon chain length & unsaturation degree Engine test THC Effect of molecular structure Chain length Increase Incresing Unsaturation degree Decrease Alcohol + Diesel CO NOx Increase No clear trend Decrease Increase Methyl esters Chain length Unsaturation Soot Increase Effect of alcohols Decrease C12:0 C14:0 C16:0 C18:0 C18:1 C18:0 C18:1 30
Results. Effect of molecular structure of biodiesel on alcohol-diesel blends: hydroxyl group Temperature ( o C) NO X (g/kwh) Energy (kj/mol) 14 12 Diesel Diesel+Butanol+RME Diesel+Butanol+COME Diesel+Butanol+RME (C18:1) Density Viscosity Lubricity Miscibility 8 6 Improving trade-off 4 0.05 0.15 0.25 0.35 0.45 10 Soot (g/kwh) Diesel+Butanol+ COME (C18:1 OH) Density Viscosity Lubricity Miscibility 500 480 Soot oxidation temperature Activation energy 140 120 100 460 80 440 Diesel Diesel+Butanol +RME Diesel+Butanol +COME 60 31
Results. Effect of hydrogen on alcohol blends Hydrogen Fresh air inlet Fuel injector EGR valve Intake manifold Exhaust manifold Emission analyser 1-Cylinder diesel engine Exhaust gas out 32
Results. Effect of hydrogen on alcohol blends Carbonaceous gas emissions H PM and NOx 2 H 2 NO X PM H 2 THC Alcohol + Biodiesel EGR NO X Hydrogen H 2 CO 33
Conclusions Parameter THC CO NO X PM Chain length Unsaturation degree Hydroxyl group Decrease O 2 Increase viscosity Decrease viscosity Decrease O 2 Increase viscosity Decrease viscosity Decrease O 2 NO X Increase CN NO X Increase BM NO X Increase AFT NO X Increase BM Decrease CN Increase AFT Decrease O 2 Increase melting point Increase viscosity Decrease melting point Decrease viscosity Increase O 2 THC Increase viscosity THC Increase O 2 THC Increase viscosity THC Decrease CN Less soot Increase O 2 More potential of OH Hydrogen Liquid fuel replacement Liquid fuel replacement High flame speed Increase HO 2 radicals Liquid fuel replacement Increase OH radicals 34
School of Mechanical Engineering Thank you for your attention 35