Boulder City, CO, United States
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Yanowitz J.,Ecoengineering Inc. | Knoll K.,National Renewable Energy Laboratory | Knoll K.,SGS Environmental Testing Corporation | Luecke J.,National Renewable Energy Laboratory | McCormick R.L.,National Renewable Energy Laboratory
Environmental Science and Technology | Year: 2013

Nine flex-fuel vehicles meeting Tier 1, light duty vehicle-low emission vehicle (LDV-LEV), light duty truck 2-LEV (LDT2-LEV), and Tier 2 emission standards were tested over hot-start and cold-start three-phase LA92 cycles for nonmethane organic gases, ethanol, acetaldehyde, formaldehyde, acetone, nitrous oxide, nitrogen oxides (NOx), carbon monoxide (CO), and carbon dioxide (CO2), as well as fuel economy. Emissions were measured immediately after refueling with E40. The vehicles had previously been adapted to either E10 or E76. An overall comparison of emissions and fuel economy behavior of vehicles running on E40 showed results generally consistent with adaptation to the blend after the length of the three-phase hot-start LA92 test procedure (1735 s, 11 miles). However, the single LDT2-LEV vehicle, a Dodge Caravan, continued to exhibit statistically significant differences in emissions for most pollutants when tested on E40 depending on whether the vehicle had been previously adapted to E10 or E76. The results were consistent with an overestimate of the amount of ethanol in the fuel when E40 was added immediately after the use of E76. Increasing ethanol concentration in fuel led to reductions in fuel economy, NOx, CO, CO2, and acetone emissions as well as increases in emissions of ethanol, acetaldehyde, and formaldehyde. © 2013 American Chemical Society.

Agency: European Commission | Branch: FP7 | Program: CP-IP | Phase: KBBE-2007-3-3-02 | Award Amount: 7.36M | Year: 2008

BACSIN is a 16-member consortium with the main focus to improve rational exploitation of the catalytic properties of bacteria for the treatment and prevention of environmental pollution. Current application of bacteria in the environment is hindered by the lack of knowledge on the effects of stresses on cellular activity, most importantly abiotic stresses prevailing on site (e.g., desiccation or nutrient starvation), stresses as a result of pollution itself (e.g., toxicity), and those during strain preparation and formulation. BACSIN proposes four iterative poles of research and technology to overcome this hindrance for subsequent improved microbial usage. The 1st pole will investigate genome-wide catabolic and stress expression in a set of different pollutant degrading bacteria (the BACSINs). Key cellular factors and regulatory networks determining the interplay between stress-survival and pollutant catabolism will be unveiled, and faithful predictive models for cell behaviour produced. The 2nd pole will study stress resistance, survival and activity of BACSINs in real polluted environments, via microcosms and in situ traps, plant roots and leaves, while accentuating possible effects on native communities. The 3d pole will focus on the original microbial communities at contaminated sites, to discover and exploit more optimal stress and survival resistance among resident pollutant-degrading bacteria. We will develop molecular diagnostics tools to screen contaminated sites for catabolic and stress parameters, and decide whether BACSIN complementation should be considered. Promising isolates of resident bacteria will be studied as new BACSINs, to show the usefulness of the diagnosis-isolation-reintroduction approach for enhancing pollutant biodegradation rates. Finally, we will focus on BACSIN formulations, to understand the stresses on bacteria during growth, preservation and resuscitation, and to produce optimally active cells for environmental application.

McCormick R.L.,National Renewable Energy Laboratory | Ratcliff M.A.,National Renewable Energy Laboratory | Christensen E.,National Renewable Energy Laboratory | Fouts L.,National Renewable Energy Laboratory | And 5 more authors.
Energy and Fuels | Year: 2015

Oxygenates present in partially hydroprocessed lignocellulosic-biomass pyrolysis oils were examined for their impact on the performance properties of gasoline and diesel. These included: methyltetrahydrofuran, 2,5-dimethylfuran (DMF), 2-hexanone, 4-methylanisole, phenol, p-cresol, 2,4-xylenol, guaiacol, 4-methylguaiacol, 4-methylacetophenone, 4-propylphenol, and 4-propylguaiacol. Literature values indicate that acute toxicity for these compounds falls within the range of the components in petroleum-derived fuels. On the basis of the available data, 4-methylanisole and by extension other methyl aryl ethers appear to be the best drop-in fuel components for gasoline because they significantly increase research octane number and slightly reduce vapor pressure without significant negative fuel property effects. A significant finding is that DMF can produce high levels of gum under oxidizing conditions. If the poor stability results observed for DMF could be addressed with a stabilizer additive or removal of impurities, it could also be considered a strong drop-in fuel candidate. The low solubility of phenol and p-cresol (and by extension, the two other cresol isomers) in hydrocarbons and the observation that phenol is also highly extractable into water suggest that these molecules cannot likely be present above trace levels in drop-in fuels. The diesel boiling range oxygenates all have low cetane numbers, which presents challenges for blending into diesel fuel. There were some beneficial properties observed for the phenolic oxygenates in diesel, including increasing conductivity, lubricity, and oxidation stability of the diesel fuel. Oxygenates other than phenol and cresol, including other phenolic compounds, showed no negative impacts at the low blend levels examined here and could likely be present in an upgraded bio-oil gasoline or diesel blendstock at low levels to make a drop-in fuel. On the basis of solubility parameter theory, 4-methylanisole and DMF showed less interaction with elastomers than ethanol, while phenolic compounds showed somewhat greater interaction. This effect is not large, especially at low blend levels, and is also less significant as the size and number of alkyl substituents on the phenol ring increase. © 2015 American Chemical Society.

Christensen E.,National Renewable Energy Laboratory | Christensen E.,Ecoengineering Inc. | Christensen E.,Trenton Fuel Works LLC | Christensen E.,Meadwestvaco Corporation | And 20 more authors.
ACS National Meeting Book of Abstracts | Year: 2011

Properties of ethyl and n-butyl levulinate, two potential cellulose-derived fuel blend components, were assessed for the neat oxygenates and for blends with diesel and gasoline. Chemical and physical properties of fuel blends were compared to the requirements of ASTM specifications D4814 for gasolines and D975 for diesel fuel oils to determine their utility as fuel extenders. Both esters exhibit very low cetane number requiring use of a cetane improver, but increase octane numbers of gasolines. Diesel blends with ethyl levulinate were found to separate into two liquid phases at low temperatures; however n-butyl levulinate remained in solution and had no effect on diesel cloud point. Water exposure of gasoline-levulinate blends showed improved oxygenate extraction resistance compared to ethanol. Both esters were found to significantly increase diesel lubricity and conductivity. Butyl levulinate blended in gasoline to 2.7 wt% oxygen caused the distillation end point to exceed 225°C, thus failing the specification.

Ratcliff M.A.,U.S. Department of Energy | Luecke J.,U.S. Department of Energy | Williams A.,U.S. Department of Energy | Christensen E.,U.S. Department of Energy | And 3 more authors.
Environmental Science and Technology | Year: 2013

Certification gasoline was splash blended with alcohols to produce four blends: ethanol (16 vol%), n-butanol (17 vol%), i-butanol (21 vol%), and an i-butanol (12 vol%)/ethanol (7 vol%) mixture; these fuels were tested in a 2009 Honda Odyssey (a Tier 2 Bin 5 vehicle) over triplicate LA92 cycles. Emissions of oxides of nitrogen, carbon monoxide, non-methane organic gases (NMOG), unburned alcohols, carbonyls, and C1-C8 hydrocarbons (particularly 1,3-butadiene and benzene) were determined. Large, statistically significant fuel effects on regulated emissions were a 29% reduction in CO from E16 and a 60% increase in formaldehyde emissions from i-butanol, compared to certification gasoline. Ethanol produced the highest unburned alcohol emissions of 1.38 mg/mile ethanol, while butanols produced much lower unburned alcohol emissions (0.17 mg/mile n-butanol, and 0.30 mg/mile i-butanol); these reductions were offset by higher emissions of carbonyls. Formaldehyde, acetaldehyde, and butyraldehyde were the most significant carbonyls from the n-butanol blend, while formaldehyde, acetone, and 2-methylpropanal were the most significant from the i-butanol blend. The 12% i-butanol/7% ethanol blend was designed to produce no increase in gasoline vapor pressure. This fuel's exhaust emissions contained the lowest total oxygenates among the alcohol blends and the lowest NMOG of all fuels tested. © 2013 American Chemical Society.

Yanowitz J.,Ecoengineering Inc. | McCormick R.L.,National Renewable Energy Laboratory
SAE International Journal of Fuels and Lubricants | Year: 2016

Spark-ignition engine fuel standards have been put in place to ensure acceptable hot and cold weather driveability (HWD and CWD). Vehicle manufacturers and fuel suppliers have developed systems that meet our driveability requirements so effectively that drivers overwhelmingly find that their vehicles reliably start up and operate smoothly and consistently throughout the year. For HWD, fuels that are too volatile perform more poorly than those that are less volatile. Vapor lock is the apparent cause of poor HWD, but there is conflicting evidence in the literature as to where in the fuel system it occurs. Most studies have found a correlation between degraded driveability and higher dry vapor pressure equivalent or lower TV/L = 20, and less consistently with a minimum T50. For CWD, fuels with inadequate volatility can cause difficulty in starting and rough operation during engine warmup. The Driveability Index (DI)-a function of T10, T50, and T90-is well correlated with CWD in hydrocarbon fuels. For ethanol-containing fuels, a correction factor to the DI equation improves the correlation with CWD, although the best value for that factor has still not been determined. Ethanol increases the heat of vaporization. However, this is likely insignificant for E15 and lower concentration fuels. The impact of ethanol on driveability is likely due to its direct effect on vapor pressure at cold temperatures. For E51-E83 or flex-fuel blends, ASTM sets a minimum vapor pressure; however, published data suggest that a correction for the amount of ethanol in the fuel is needed to accurately predict CWD, possibly because ethanol has a higher lower-flammability limit. .

Christensen E.,National Renewable Energy Laboratory | Yanowitz J.,Ecoengineering Inc. | Ratcliff M.,National Renewable Energy Laboratory | McCormick R.L.,National Renewable Energy Laboratory
Energy and Fuels | Year: 2011

The oxygenates ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 2-methyl-1-propanol (isobutanol), 1-pentanol, 3-methyl-1-butanol (isopentanol), methyl levulinate, ethyl levulinate, butyl levulinate, 2-methyltetrahydrofuran (MTHF), 2-methylfuran (MF), and 2,5-dimethylfuran (DMF) were blended in three gasoline blendstocks for oxygenate blending (BOBs) at levels up to 3.7 wt % oxygen. Chemical and physical properties of the blends were compared to the requirements of ASTM specification D4814 for spark-ignited engine fuels to determine their utility as gasoline extenders. Vapor pressure, vapor lock protection, distillation, density, octane rating, viscosity, and potential for extraction into water were measured. Blending of ethanol at 3.7% oxygen increased vapor pressure by 5-7 kPa as expected. 2-Propanol slightly increased vapor pressure in the lowest-volatility BOB, while all other oxygenates caused a reduction in vapor pressure of up to 10 kPa. Coefficients for the Wilson equation were fitted to the measured vapor pressure data and were shown to adequately predict the vapor pressure of oxygenate-gasoline blends for five individual alcohols and MTHF in different gasolines. Higher alcohols and other oxygenates generally improved vapor lock protection. Butyl levulinate blended at 2.7% oxygen caused the distillation end point to exceed 225 °C, thus failing the specification. Distillation parameters were within specification limits for the other oxygenates tested. Other than ethanol, MF, and DMF, the oxygenates examined will not produce blends with satisfactory octane ratings at these blend levels when blended into lower-octane blendstocks designed for ethanol blending. However, all oxygenates tested except 1-pentanol and MTHF produced an increase in octane rating. For ethanol, the propanol isomers, and methyl levulinate, 20 wt % or more of the oxygenate could be extracted into water in a room-temperature water tolerance experiment. For the butanol isomers and ethyl levulinate, the percent extracted ranged from about 4% to 8%. Extraction for other oxygenates was 2% or lower. Methyl levulinate separates from gasoline as a separate liquid phase at temperatures below 0 °C. © 2011 American Chemical Society.

Alleman T.L.,National Renewable Energy Laboratory | McCormick R.L.,National Renewable Energy Laboratory | Yanowitz J.,Ecoengineering Inc.
Energy and Fuels | Year: 2015

This project looks at the potential of blending ethanol with natural gasoline to produce Flex-Fuels (ASTM D5798-13a) and high-octane, mid-level ethanol blends. Eight natural gasoline samples were collected from pipeline companies or ethanol producers around the United States. Analysis of the natural gasoline shows that the samples are 80-95% paraffinic, 5-15% naphthenic, 3% or less aromatics, and the balance olefins. The paraffins were typically pentane and isopentanes. The benzene content ranged from approximately 0.1 to 1.2 wt % such that blends of E30 or more would meet United States Environmental Protection Agency (U.S. EPA) limits for the benzene content in gasoline. The sulfur content in the natural gasoline ranged between 4 and 146 ppm. Assuming the lowest ethanol content in Flex-Fuel of 51 volume percent (vol %), a natural gasoline blendstock would be required to have 20 ppm sulfur or less for the finished fuel to meet the upcoming U.S. EPA Tier 3 gasoline sulfur limit. The research octane number (RON) (ASTM D2699-13) for the natural gasoline ranged from 67 to 72. Vapor pressure (ASTM D5191-13) ranged from 89 to 101 kPa. Two natural gasoline samples were selected for blending with ethanol. To make a 91 RON fuel (typical of U.S. regular gasoline), natural gasoline had to be blended with 30 vol % ethanol. Because of the high vapor pressure of these blendstocks, over 70 vol % ethanol could be blended into Flex-Fuel while still meeting the class 4 (wintertime) minimum vapor pressure requirement of 66 kPa. For blending of class 1 (summertime) Flex-Fuel, a minimum of 74 vol % ethanol was required to stay below the 62 kPa upper limit on vapor pressure. Modeling of vapor pressure using universal quasichemical functional-group activity coefficients (UNIFAC) and Wilson equation-based approaches provided good agreement with experimental data for most samples. © 2015 American Chemical Society.

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