[Due to the increasing size of the archives, each topic page now contains only the prior 365 days of content. Access to older stories is now solely through the Monthly Archive pages or the site search function.]
Study finds butanol-gasoline blends effective to control soot from CI engines under Low Temperature Combustion
January 31, 2014
|(Left) Thermal efficiency and (right) soot from different gasoline-butanol blends at different EGR rates. Yang et al. Click to enlarge.|
A study by a team at Tianjin University found that the addition of n-butanol to gasoline for use in a compression ignition engine (CI) under Low Temperature Combustion (LTC) conditions has a significant effect on soot reduction. The peak soot value of a 30% butanol blend (B30) was 85% lower than that of pure gasoline; the EGR rate that corresponds to the peak value of soot is also decreased with the higher n-butanol fraction. Their study is published in the journal Fuel.
Partially Premixed Combustion involving the injection of gasoline fuel into CI engines is being explored by other researchers as a means to reducing simultaneously NOxand soot emissions. High octane fuels such as gasoline are preferred for high-efficiency and clean combustion at high engine loads, the Tianjin researchers note.
Oak Ridge Lab study finds E30 blend and EGR can deliver significant efficiency improvements in optimized SI engines
January 17, 2014
Researchers at Oak Ridge National Laboratory’s National Transportation Research Center (NTRC) report that an E30 (30% ethanol) mid-level ethanol blend shows promise as a means for significant improvement in vehicle efficiency in optimized spark-ignited (SI) engines. Results of the study by Derek Splitter and Jim Szybist suggest that it could be possible to implement a 40% downsize + downspeed configuration (1.2 L engine) into a representative midsize sedan using this combination of optimized engine and mid-level alcohol blend.
As an example, for a midsize sedan at a 65 mph (105 km/h) cruise, estimated fuel efficiency of 43.9 mpg (5.4 l/100 km) with engine-out CO2 of 102 g/km could be achieved with similar reserve power to a 2.0 L engine fueled with regular gasoline (38.6 mpg/6.1 l/100km, engine out CO2 of 135 g/km). The data suggest that, with midlevel alcohol–gasoline blends, engine and vehicle optimization can offset the reduced fuel energy content of alcohol–gasoline blends and likely reduce vehicle fuel consumption and tailpipe CO2 emissions.
US Army flies Black Hawk with 50:50 isobutanol-derived alcohol-to-jet fuel blend
December 23, 2013
Bio-isobutanol company Gevo, Inc. announced that the US Army has successfully flown the Sikorsky UH-60 Black Hawk helicopter on a 50:50 blend of Gevo’s ATJ-8 (Alcohol-to-Jet)—a renewable, drop-in alternative fuel for JP8 derived from isobutanol. (Earlier post.)
This flight marks the first Army Aircraft to fly on the isobutanol ATJ blend. (The US Air Force flew its first test flight using ATJ fuel in 2012. Earlier post.) The Army flight testing is being conducted at Aviation Flight Test Directorate (AFTD) on Redstone Arsenal, AL and is anticipated to be complete by March 2014.
NREL study probes emissions impact of butanol-gasoline blends in light-duty vehicles
November 26, 2013
|Summary of significant emissions results from the fuel testing. Credit: ACS, Ratcliff et al. Click to enlarge.|
Results of a study led by a team from the National Renewable Energy Laboratory on the impact of butanol-gasoline blends on light-duty vehicle emissions suggest that widespread deployment of n-butanol or i-butanol in the gasoline pool could result in changes to the estimated emissions of alcohols and carbonyls in the emissions inventory. Given equivalent deployment of butanols and ethanol, the results suggest emissions of unburned alcohols would decrease, but carbonyl emissions would increase; some of these compounds have poorly understood health effects, they note.
The carbonyls acetaldehyde and formaldehyde are classified as carcinogens or probable carcinogens by the National Institute for Occupational Safety and Health (NIOSH), International Agency for Research on Cancer, and the EPA. NIOSH considers butyraldehyde to have similar reactivity and mutagenicity to acetaldehyde.
Sandia partnering with MOgene on ARPA-E project for sunlight-assisted microbial conversion of methane to butanol
November 18, 2013
Researchers at Sandia National Laboratories will use their expertise in protein expression, enzyme engineering and high-throughput assays as part of a two-year, $1.5-million award led by MOgene Green Chemicals (MGC, a wholly owned subsidiary of genomics services provider MOgene) targeting the sunlight-assisted conversion of methane to butanol.
The project is one of 15 selected for a total of $34 million in funding by the Advanced Research Projects Agency-Energy (ARPA-E) as part of its Reducing Emissions using Methanotrophic Organisms for Transportation Energy (REMOTE) program. (Earlier post.) MGC’s primary corporate objective is to engineer biocatalysts with novel functionality for production of molecules from non-food feedstocks that can be used for production of transportation fuel as well as commodity and specialty products.
Taiwan’s ITRI introduces cellulosic bio-butanol production technology; pathway with highest carbon conversion yield
October 29, 2013
ITRI (Industrial Technology Research Institute), a Taiwan-based high-tech applied research institution, is introducing ButyFix, a technology for cellulosic bio-butanol production with a negative carbon footprint. ButyFix uses a three-step process: (1) the hydrolysis of cellulose and hemicellulose to release sugars; (2) fermentation of the sugars to produce butyrate; and (3) the chemical conversion of butyrate via esterification and hydrogenation to butanol.
ITRI uses a metal salt/organic acid “eco-solvent” in its hydrolysis process; the crystalline structure of cellulose is first destroyed, forming a soluble ester, which is then hydrolyzed by the organic acid to glucose. The process operates in mild temperatures; benchmarking results cited by ITRI show a 95 wt.% total sugar yield.
Butamax and Highwater Ethanol break ground on biobutanol retrofit project
October 04, 2013
|Converting a corn ethanol plant to produce biobutanol requires changes to the fermentation step (mainly a new microorganism) and to alcohol recovery from the fermentation. Source: Butamax. Click to enlarge.|
Butamax Advanced Biofuels LLC, the biobutanol technology company formed as a joint venture between DuPont and BP, and Highwater Ethanol LLC, a producer of first-generation corn ethanol, have begun to retrofit Highwater’s ethanol plant in Lamberton, Minnesota for the production of bio-isobutanol.
Butamax’s technology package will include the installation of novel corn oil separation technology. Butamax and Highwater have entered into definitive agreements for license of Butamax’s patented corn oil separation technology, which is an integral part of a full retrofit to biobutanol production and can also be installed independently as a first phase of the conversion.
Gevo opens renewable paraxylene plant next to renewable jet fuel plant; bio-isobutanol biorefinery
August 27, 2013
Bio-isobutanol producer Gevo, Inc. held a ribbon-cutting ceremony for its demonstration-scale paraxylene (p-xylene) plant in Silsbee, Texas. The paraxylene facility is located adjacent to Gevo’s existing jet fuel plant in Silsbee, and establishes the site as a biorefinery that will serve the renewable chemicals and drop-in biofuels markets.
Gevo has been working with The Coca-Cola Company since 2011 (earlier post) to deliver a new production technology for renewable paraxylene, a key building block for producing fully renewable PET for beverage bottles. Research and Development support for this plant was provided by The Coca-Cola Company under a Joint Development Agreement.
New synthetic fungal-bacterial consortia for direct production of isobutanol from biomass
August 20, 2013
A team from the University of Michigan, Michigan State, and UCLA has designed synthetic fungal-bacterial consortia for the direct production of isobutanol from biomass. The required biological functions are divided between two specialists: the fungus Trichoderma reesei, which secretes cellulase enzymes to hydrolyze lignocellulosic biomass into soluble saccharides, and the bacterium Escherichia coli, which metabolizes soluble saccharides into the desired products.
In experiments reported in an open access paper published in the Proceedings of the National Academies (PNAS), they achieved isobutanol titers up to 1.88 g/L and yields up to 62% of theoretical maximum from the direct conversion of microcrystalline cellulose and pretreated corn stover to isobutanol.
Gevo supplies US Coast Guard with isobutanol-blended gasoline for testing in marine applications
July 24, 2013
|Coast Guard crewmembers train aboard a 38-foot Special Purpose Craft – Training Boat. Source: USCG. Click to enlarge.|
Biobutanol producer Gevo, Inc. has begun supplying the U.S. Coast Guard R&D Center with initial quantities of finished 16.1% renewable isobutanol-blended gasoline for engine testing.
The US Coast Guard R&D Center is using the Gevo-blended fuel as part of a 12-month, long-term operational study on marine engines that began during June. The testing is being performed under a Cooperative Research and Development Agreement (CRADA) between the US Coast Guard, Honda, and Mercury and will focus on two of the Coast Guard’s platform boats: 38-foot Special Purpose Craft - Training Boat and the 25-foot Response Boat - Small.
New catalysts convert ethanol to butanol with high selectivity; potential low-cost upgrade for ethanol plants
April 11, 2013
Researchers at the University of Bristol (UK) have developed a new family of catalysts that enables the conversion of ethanol into n-butanol—a higher alcohol with better characteristics for transportation applications than ethanol—with selectivity of more than 95% at good conversion. The team presented a pair of papers on their work at the Spring meeting of the American Chemical Society this week in New Orleans.
While butanol has emerged as a potential sustainable liquid fuel replacement for gasoline, development of biosynthetic pathways for its synthesis are challenged by very low conversion and modest selectivity, they noted. Although catalytically upgrading the more readily available bioethanol to butanol is theoretically attractive, this has been hampered by modest selectivity in most cases.
Navigant forecasts global 6% CAGR for biofuels to 2023
March 29, 2013
|Total Biofuels production by fuel type, world markets: 2013-2023. Source: Navigant. Click to enlarge.|
Navigant Research forecasts global biofuels production will grow at a compound annual growth rate (CAGR) of 6% between 2013 and 2023, despite slower than expected development of advanced biofuels pathways (such as cellulosic biofuels); an expected expansion in unconventional oil production in key markets such as the United States; and a decline in global investment for biofuels in recent years.
In contrast, Navigant expects the CAGR for fossil-based gasoline, diesel, and jet fuel to be 3.1% over the forecast period. The research firm projects that total biofuels production will reach 62 billion gallons by 2023 or 5.9% of global transportation fuel production from fossil sources.
Study explores impact of alcohol-gasoline blends with early inlet valve closing at low and moderate loads on EGR tolerance
March 20, 2013
A team from Brunel University, MAHLE Powertrain and University College London studied the combined effects of different inlet valve operating strategies on combustion, performance and emissions with different ethanol and 1-butanol blends with gasoline in a single-cylinder spark-ignition research engine equipped with a fully variable valvetrain. Their paper is published in the journal Fuel.
The focus was to better quantify the effects of alcohol content and Early Inlet Valve Closing (EIVC) operation on EGR tolerance under the lowest speed-load conditions typically encountered (e.g., engine idle) while also quantifying the changes in optimum valvetrain settings at moderate speeds and loads where the effects of varying EGR tolerance were less dominant.
MIT team shows targeting metabolic pathways to mitochondria significantly boosts yeast production of isobutanol; potential for other chemicals as well
February 18, 2013
Researchers from MIT and the Whitehead Institute for Biomedical Research have devised a way to boost significantly isobutanol production in yeast by engineering isobutanol synthesis to take place entirely within mitochondria.
They showed that targeting metabolic pathways to mitochondria can increase production compared with overexpression of the enzymes involved in the same pathways in the cytoplasm. Compartmentalization of the Ehrlich pathway—a three-step catalytic breakdown of valine that produces isobutanol, earlier post—into mitochondria increased isobutanol production by 260%, whereas overexpression of the same pathway in the cytoplasm only improved yields by 10%, compared with a strain overproducing enzymes involved in only the first three steps of the biosynthetic pathway. A paper on their work is published in the journal Nature Biochemistry.