Abstract
The U.S. Renewable Fuel Standard (RFS2) requires a drastic increases in production of advanced biofuels up to 36 billion gallons over the next decade while corn-based ethanol will be capped at 15 billion gallons. Currently ethanol is the predominant alternative fuel and is widely distributed at 10 vol % blends in gasoline (E10). However, certain properties of ethanol make it less desirable as a blending agent in particular at higher blend levels. Therefore the engine- and vehicle-related properties of longer chain alcohols are evaluated in comparison to gasoline to determine their suitability as blending agents for spark-ignition engine fuels. This analytical study aims at providing comprehensive property data for a range of alcohol isomers with a carbon count up to C8. Relevant physical property data is used to determine the general suitability of longer chain alcohol isomers as blending agents based on factors such as melting point and boiling. Based on initial findings the scope of the study was narrowed down to alcohols in the C2–C6 range. It was determined that the engine- and combustion-relevant information is missing from the literature for a wide range of longer chain isomers. Thus fuel testing for engine-relevant properties such as lower heating value, knock resistance (RON, MON) and Reid Vapour Pressure (RVP) for alcohols up to C6 was performed as part of this study. Data suggests that the melting point of alcohols increases with increasing carbon count and all C7 and C8 isomers exhibit melting points in excess of −40 °C making their use as vehicle fuel questionable. Boiling points increase with increasing carbon count and n-structures generally have slightly higher boiling points than their respective iso-structures. Latent heat of vaporization decreases with carbon count, the mass-specific value for ethanol is triple that of gasoline, the energy specific ratio increases to a factor of 5. Alcohol fuels generally have a significantly lower RVP than gasoline, RVP decreases with increasing carbon count. Stoichiometric air demand and fuel energy content increase with carbon count. Knock resistance expressed as Research Octane Number (RON) and Motor Octane Number (MON) decreases significantly with increasing carbon count, iso-structures show increased knock resistance compared to their respective n-structures. This study is limited to analytical results as well as fuel property testing according to ASTM standards. Only properties of neat alcohols are evaluated in comparison to gasoline certification fuel, gasoline blend stock for ethanol blending and E10. The analysis of the reported properties is further focused on spark-ignition engine applications only. Future phases of this project will include the assessment of properties of multi-component blends as well as efficiency, performance and emissions testing on a modern direct-injection engine. While data for a limited number of commonly used alcohols such as ethanol and iso-butanol is available in the literature, little or no data is available for a majority of other alcohols and their isomers. In addition, engine-related data published in the past occasionally disregards the significant differences between alcohol isomers of the same chain length. This study offers a comprehensive review of physical properties of alcohols and their common isomers in the C2–C8 range as they relate to in-vehicle use and spark-ignition combustion engine application. Data presented in this paper suggests that higher alcohols have certain physical properties that might be desirable for blending with gasoline. Due to their oxygen content all alcohols have an inherent disadvantage in terms of energy content compared to non-oxygenated fuels. While this disadvantage becomes less pronounced with increasing carbon count, other less desirable properties such as a low RVP and reduced knock resistance become more dominant with longer chain length alcohols. In addition to merely evaluating properties, the selection of promising alcohols and blend levels will ultimately depend on the introduction scenario and target properties.
F2012-B01-004
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
References
Environmental Protection Agency (EPA) (2011) Partial grant of clean air act waiver application submitted by growth energy to increase the allowable ethanol content of gasoline to 15 percent. Federal Register Vol. 76, No. 17. 2011
Whims S (2002) Pipeline considerations for ethanol. Department of agricultural economics. Kansas State University
Pischinger R, Klell M, Sams T (2002) Thermodynamics of internal combustion engines (in German: Thermodynamik der verbrennungskraftmaschine). Springer, Wien. ISBN 3-211-83679-9
Stein R, Polovina D, Roth K, Foster M et al (2012) Effect of heat of vaporization, chemical octane, and sensitivity on knock limit for ethanol–gasoline blends. SAE Int J Fuels Lubr 5(2):823–843. doi:10.4271/2012-01-1277
Kasseris E, Heywood J (2012) Charge cooling effects on knock limits in SI DI engines using gasoline/ethanol blends: part 1-quantifying charge cooling, SAE Technical Paper 2012-01-1275, doi:10.4271/2012-01-1275
Kasseris E, Heywood J (2012) Charge cooling effects on knock limits in si di engines using gasoline/ethanol blends: part 2-effective octane numbers. SAE Int J Fuels Lubr 5(2):844–854. doi:10.4271/2012-01-1284
ASTM standard ASTM D5191–10b (2007) Standard test method for vapor pressure of petroleum products (mini method). ASTM international, West conshohocken, PA, doi:10.1520/D5191-10B, www.astm.org
Andersen VF, Anderson JE, Wallington TJ, Mueller SA, Nielsen OJ (2010) Vapor pressures of alcohol-gasoline blends. Energy Fuels 24:3647–3654
Mittal V, Heywood J (2008) The relevance of fuel RON and MON to knock onset in modern SI engines. SAE Technical Paper 2008-01-2414, 1(1):1366–1380 doi: 10.4271/2008-01-2414
Mittal V, Heywood J (2010) The shift in relevance of fuel RON and MON to knock onset in modern SI engines over the last 70 Years. SAE Int J Engines 2(2):1–10. doi:10.4271/2009-01-2622
Kalghatgi G (2001) Fuel anti-knock quality—part I. engine studies. SAE Technical Paper 2001-01-3584, doi:10.4271/2001-01-3584
Kalghatgi G (2001) Fuel anti-knock quality–part II. Vehicle studies–how relevant is motor Octane Number (MON) in modern engines? SAE Technical Paper 2001-01-3585, 2001, doi:10.4271/2001-01-3585
Section 201–202 Renewable Fuel Standard (RFS) Energy Independence and Security Act of 2007 (Pub. L. 110–140, originally named the CLEAN Energy Act of 2007)
Acknowledgments
This work was funded by the Iowa Corn Promotion Board as part of a project to determine properties of multi-component alcohol gasoline blends. The authors wish to thank Rodney Williamson and David Ertl of Iowa Corn Promotion Board/Iowa Corn Growers Association for their support and the valuable discussions. The submitted manuscript has been created by UChicago Argonne, LLC, Operator of Argonne National Laboratory (“Argonne”). Argonne, a U.S. Department of Energy Office of Science laboratory, is operated under Contract No. DE-AC02-06CH11357. The U.S. Government retains for itself, and others acting on its behalf, a paid-up nonexclusive, irrevocable worldwide license in said article to reproduce, prepare derivative works, distribute copies to the public, and perform publicly and display publicly, by or on behalf of the Government.
Author information
Authors and Affiliations
Corresponding author
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2013 Springer-Verlag Berlin Heidelberg
About this paper
Cite this paper
Wallner, T., Ickes, A., Lawyer, K. (2013). Analytical Assessment of C2–C8 Alcohols as Spark-Ignition Engine Fuels. In: Proceedings of the FISITA 2012 World Automotive Congress. Lecture Notes in Electrical Engineering, vol 191. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-33777-2_2
Download citation
DOI: https://doi.org/10.1007/978-3-642-33777-2_2
Published:
Publisher Name: Springer, Berlin, Heidelberg
Print ISBN: 978-3-642-33776-5
Online ISBN: 978-3-642-33777-2
eBook Packages: EngineeringEngineering (R0)