Robert L. McCormick, Matthew Ratcliff, Bradley T. Zigler

Transcription

1 Emerging and Future Biofuels Robert L. McCormick, Matthew Ratcliff, Bradley T. Zigler CRC Advanced Fuel and Engine Efficiency Workshop Baltimore, MD February 26, 2014 NREL is a national laboratory of the U.S. Department of Energy, ffice of Energy Efficiency and Renewable Energy, operated by the Alliance for Sustainable Energy, LLC.

2 The Big Picture: Achieving 80% C 2 Reduction h/km) Typical Car Today Hig gher Vehicle e Efficiency Vehicle En nergy Consum mption (kw g/km 129 g/km g/km Carbon Intensity of Energy Carrier (g/kwh) Reduced Carbon Intensity Constraints: Cost, Scale, Safety. Consumer Choice, Environmental Impact, Policy (Urban Planning) 2

3 Fuel Enabled Trends in Engine Efficiency Spark Ignition Compression Ignition Current CR limited to about 10 because of engine knock at higher values Smaller, highly boosted engine operated at low speed is more efficient and also knock limited Enabled by higher knock resistance fuel (RN, HV, flame speed) Lower compression ratio reduces friction, engine size/weight, and Nx Lower weight parts higher engine speed Trend towards reduced CR, but CR<15 is not achieved, primarily due to cold start problems Lower CR and higher speed enabled by higher cetane number fuel 3

4 Biomass Based Gasoline ptions Sugar: corn, cane, or biomass Biochemical Ethanol Commercial scale Conversion Isobutanol Pilot scale Catalytic Rf Reforming Renewable e abegasoline Pilot scale Fast Pyrolysis Hydrotreating Lignocellulosic Biomass Gasification Alcohol Synthesis Acid/Base Depolymerization Upgrading Renewable Gasoline Mixed Alcohols Pilot scale Bench scale Gasoline xygenates Bench scale Algal Biomass Sunlight Hydrothermal Liquefaction Hydrotreating Photosynthesis t s Metabolic Renewable Gasoline Pilot Scale? Ethanol Pilot Scale? Engineering Renewable Gasoline? 4

5 Ethanol Enables Efficient Engine Technologies Eh Ethanol research octane number is higher h than that of today s hydrocarbon gasoline For direct injection engines fuel evaporation occurs in the cylinder cooling the charge and reducing knock tendency Alcohols have significantly higher heat of vaporization (HoV) leading to a higher effective RN Nakata, et al. Int. J. Engine Res (2011) Andersen, et al., Fuel (2012) 5

6 Vapor Press ure, kpa RN Isobutanol Ethanol (110) 1-Butanol (96) Isobutanol (106) Volume Percent xygenate Summer BB Ethanol 1-Butanol Isobutanol Volume Percent xygenate Higher energy content, t much lower water solubility Similar or identical GHG emission reduction as ethanol Refiners make sub-octane hydrocarbon blendstock Meets AKI requirement when ethanol is added Isobutanol may not be high enough octane Butanols lower RVP of gasoline Allows blending of higher levels of butane and pentane year round Worth billions of dollars annually to North American refiners? Heat of vaporization lower than ethanol (579 kj/kg vs 837 kj/kg), but greater than hydrocarbon (350 to 400 kj/kg) 6

7 Cellulose Derived xygenates Acidcatalyzed catalyzed deconstruction of cellulose/hemicellulose, or pyrolysis Some potential oxygenate products have very high octane numbers, insoluble in water, low heat of vaporization RN >160 Knock Resistance Metrics Multiple high octane bio derived materials RN, HV, Flame Speed must all be considered d (and other factors?) How to specify knock resistance in a fuel standard? 96 94? 92 RN Volume Percent xygenate Ethanol (110) 2-Methyl Furan (155) Dimethyl Furan (153) Methyl Levulinate (107) Methyl pentanoate (104) 4-Methyl Anisole (166)

8 Biomass Based Diesel ptions ils and Greases (Algae) Biodiesel Production Hydrotreating Biodiesel Renewable Diesel Commercial scale Sugar: corn, cane, or biomass Biochemical Conversion Catalytic Reforming Biodiesel Renewable Diesel Renewable Diesel Pilot scale Fast Pyrolysis Hydrotreating Lignocellulosic Biomass Gasification FT Synthesis Renewable Diesel FT Diesel/ Renewable Diesel Demonstrated Algal Biomass Hydrothermal Liquefaction Hydrotreating Renewable Diesel Pilot Scale? Sunlight Photosynthesis Metabolic Engineering Renewable Diesel? 8

9 High Cetane Biomass Based Diesel: Biodiesel, Hydrogenated Esters and Fatty Acids, Terpeniods HEFA fuels are highly hl isomerized i (85%+) to lower CP Terpene hydrogenation/ring opening leads to a very limited it group of hydrocarbon products Large life cycle GHG emission reduction for ft/il fats/oils, unknown for terpenes Cetane Num mber (Derived) Fat-Derived Isoprenoid-Derived Biodiesel (FAME) HEFA Terpenoid Derived: 2,6 dimethyl octane Farnesane Biodiesel (FAME): Cloud Point, o C 9

10 Lignocellulosic Biomass Grasses Hardwoods Cellulose (C6 sugars) ~40 50% ~25 30% ther (Extractives, ash, etc.) 5 10% 15 25% Lignin (Polyaromatics) MSW Crop residues Hemicellulose (C5 and C6 sugars) Softwoods ver 1 billion annual tons available in US by 2050 Potentially 80+ billion annual gallons of biofuel 400 million tons available today Wide range of costs 10

11 Ligno Cellulosic Biomass to Hydrocarbon Biofuels? H C 3 H CH 3 CH CH 3 3 H CH 3 CH 3 H H H H H CH 3 H C 3 H CH 3 H H CH CH 3 3 H H CH 3 H H H H H H H C H H H CH 3 H H H 1.4 H H H H 1.2 H H H H H 1 H H H H 0.8 H H H H H H 0.4 H H 0.2 H Lignin: 15% 25% H 0 Hemicellulose: 23% 32% Cellulose: 38% 50% H 3 C Upgrad ding Cost ($/gge e) Biomass has high oxygen content: 40 to 60 wt% Molar /C about 0.6 Economicallyrejecting thisoxygen may not be possible Hydrotreating costs for fast pyrolysis oils can be very highh Arbogast, S.V., xygen Content in Final Product (wt%) 11

12 Biomass Derived xygenate Boiling Points T 10 Gasoline T 90 EP Selected based on analysis of hydrotreated pyrolysis oil boiling fractions in Christensen, E., et al., Analysis of xygenated Compounds in Hydrotreated Biomass Fast Pyrolysis il Distillate Fractions Energy Fuels (2011) Jet Diesel 338 C Boiling Point, o C 12

13 Cellulose Derived Diesel xygenates Pyrolysis Propyl and other alkyl phenols: Acid deconstruction Pentylethers and esters CN=111 bp=204 C CN=96 bp=173 C Low CN, bp C 250 Do not appear to negatively affect fuel stability, cold weather performance, etc Little or noeffect on diesel Are renewable benefits properties other than CN worth the cost of higher CN blendstock or CN additives? i CN=30 bp=204 C 13

14 Summary A broad range of new biofuels are at different stages of research and development These include high octane number molecules that may be appropriate fuels for highly efficient SI engines o An important research need is for a knock resistance metric that encompassesrn, heatofvaporization, andflame speed Emerging renewable diesel fuels include: o High cetane number paraffins derived from triglycerides and terpenoids, as well as relatively l high hcetane biodiesel o Low cetane number aromatic streams that would require higher cetane blendstocks or cetane improving additives o High cetane number isoamyl and pentyl ethers While not discussed, fuel properties that might enable low temperature combustion (HCCI or PCCI) need to be better defined 14

15 References Andersen, et al., Fuel (2012) Arbogast, S.V. Upgrading Requirements for the Transport and Processing of Pyrolysis il in Conventional Petroleum Refineries, Houston, TX: Global Energy Management Institute, Christensen, E., Yanowitz, J., Ratcliff, M., McCormick, R.L. Renewable xygenate Blending Effects on Gasoline Properties Energy Fuels 25 (10) (2011). Christensen, E., Chupka, G., Luecke, J., Alleman, T.L., Iisa, K., McCormick, R.L., Franz, J.A., Elliott, D.C. Analysis of xygenated Compounds in Hydrotreated Biomass Fast Pyrolysis il Distillate Fractions Energy Fuels 25 (11) (2011). Mittal, V., Heywood, J.B. The Shift in Relevance of Fuel RN and MN to Knock nset in Modern SI Engines ver the Last 70 Years SAE Technical Paper No (2009). Nakata, et al. Int. J. Engine Res (2011). Ratcliff, M., Luecke, J., Williams, A., Christensen, E., Yanowitz, J., McCormick, R.L. Air Pollutant Emissions from a Tier 2 Bin 5 Vehicle Fueled with Higher Alcohol Blends Environ. Sci. Technol (2013). Smagala, T.G., Christensen, E., Christison, K.M., Mohler, R.E., Gjersing, E., McCormick, R.L. Hydrocarbon Renewable and Synthetic Diesel Fuel Blendstocks: Composition and Properties Energy Fuels 27 (1) (2013). Talmadge, M.S., Baldwin, R.M., Biddy, M.J., McCormick, R.L., Beckham, G.T., Ferguson, G.A., Czernik, S., Magrini-Bair, K.A., Foust, T.D., Metelski, P.D., Hetrick, C., Nimlos, M.R. A Perspective on xygenated Species in the Refinery Integration of Pyrolysis il Green Chemistry (2014). 15