Browsing by Subject "Ethanol"

Now showing 1 - 7 of 7
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    Biofuel combustion: a single particle approach including new tandem measurements.
    (2011-10) Dutcher, Dabrina D
    The physicochemical properties of aerosol particles are complex. They are often irregular in shape, and can contain complex mixtures of liquids and solids. By measuring multiple properties of a particle, it is possible to describe it more completely than is possible if only one property is evaluated. This is the principle behind the theme of this chapter: tandem aerosol measurements. The Aerosol Time-of-Flight Mass Spectrometer carries out tandem measurements of a particle's vacuum aerodynamic diameter and its composition. I describe here the use of the ATOFMS in series with instruments that measure other properties so as to provide still more information. These additional properties include particle mobility, mass, and "brightness" (i.e., the amount of light that it scatters when illuminated by a laser). In addition, we show that when the ATOFMS is used downstream of tandem differential mobility analyzer systems (TDMA), new information can be gained about species that affect a particle's hygroscopicity (HTDMA) or volatility (VTDMA). These novel instrument combinations yield information regarding the dependence of particle effective density, volatility, and hygroscopicity on particle composition. Additional information is presented about the relationship between particle mobility size and vacuum aerodynamic size for assorted particle types and about the unanticipated difficulties that I encountered when using the ATOFMS for tandem measurements. I discovered that the rotating seals in the aerosol particle mass analyzer (APM) contain compounds that volatilize and react with acidic particles. The ATOFMS is exceedingly sensitive to these reaction products, so much so that it is not possible to obtain meaningful information about the composition of the particles under investigation. This sensitivity may provide a sensitive means, however, to assess the particle acidity.
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    Effects of economy-wide factors on Brazilian economic growth and biofuels production: an inter-temporal general equilibrium analysis.
    (2011-02) Pinto, Cristina Vinyes
    Disenchantment with the Washington Consensus has led to an emphasis on growth diagnostics. In the case of Brazil, the literature suggests three main factors impeding growth: low domestic savings, a shortage of skilled workers, and a lack of investment in the country's transportation infrastructure. The unique contribution of this study is to show the inter-temporal implications of relaxing these constraints. We fit a multi-sector Ramsey model to Brazilian data, validate its fit to times data, and provide empirical insights into the economy's structural transformation to long-run equilibrium. Then, the sensitivity of these results to relaxing each of these three constraints is investigated in a manner that yields the same long-run level of wellbeing. Analytical concepts adapted from static trade theory are used to provide a detailed explanation of how the economy responds in transition growth to the relaxation of these impediments. Addressing these factors clearly benefits the economy, but they do not launch the economy to a substantially higher growth path. In order to enhance energy security and independence, Brazil has supported the production and use of ethanol. Brazil's leadership in this market reveals complex inter-linkages between ethanol, sugarcane, sugar and fossil fuels. These sectors have been growing an average of 14% per year, while the country's growth rates have been very modest. This paper presents a theoretical framework for understanding the interaction between Brazil's economic growth and the evolution of these sectors as the economy transitions toward long-run equilibrium. Then, the sensitivity of these results is analyzed under two simulations; first, a reduction of the cost of financial intermediation (which the literature identifies as one of the factors affecting Brazil's growth), and second, an increase in ethanol prices by 2.6%, based on the expectation that biofuels' world demand is increasing.
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    Effects of homogeneous charge compression ignition (HCCI) control strategies on particulate emissions of ethanol fuel.
    (2010-12) Franklin, Luke
    This thesis presents a systematic investigation into the formation of particulate matter in homogeneous charge compression ignition (HCCI) engines. These engines are representative of the emerging generation of low sooting engine technology. Early research in the field concluded that engines operating with this combustion strategy could offer Diesel like efficiency while simultaneously reducing emissions of particulate matter and the oxides of nitrogen to nearly negligible levels. While quantification of gas phase emissions has changed little through modern regulatory history, the metrics defining particulate emissions and the state of understanding of the research community are rapidly evolving. Advances in technology for characterizing particulate emissions from spark ignition and compression ignition engines have been applied to HCCI emissions and the results indicate the production of significant quantities, by both number and mass, of particles from the HCCI combustion strategy. A relationship has been identified between in-cylinder behavior, and both gaseous and particulate emissions. It has been shown to be valid for 2 different fuels and multiple engine loads. Characteristics of the particulate matter suggest it is formed via gas to particle conversion, or nucleation, of the lighter distillates from the engines lubricating oil.
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    Efficacy Of Heated Hydrous Ethanol Injection For Improving Emissions From Dual Fuel Diesel Engines
    (2017-05) Nord, Alex
    With emissions standards becoming ever more stringent, aftermarket dual-fuel solutions are being developed to allow legacy diesel engines to reach higher regulatory emissions tiers. Manufacturers are reluctant to adopt dual-fuel systems due to perceived lack of consumer interest. However, the use of aftermarket dual-fuel systems with partially renewable fuels has sparked interest in limited markets. Previous research has shown slight emissions reduction benefits from fumigation with 120 proof hydrous ethanol in a diesel engine using a commercially available dual-fuel system. However, the findings do not match manufacturer claims of emissions reductions. The work presented here examines the design, development, performance, and emissions from an engine equipped with a novel aftermarket port fuel injection (PFI) dual fuel system with a fuel heating system integrated into the fuel injector rail. Finite element modeling techniques in ANSYS were used to optimize the heat exchanger and analyze its performance. In addition, cross-sections and flow path lines were created in ANSYS to examine thermal profiles and flow turbulence at varying ethanol flow rates. A John Deere 4045HF475 Tier 2 diesel engine was retrofitted with a custom PFI rail designed to inject hydrous ethanol with the ability to preheat the ethanol using circulated hot engine coolant to improve the vaporization and mixing of the secondary fuel and air in the intake port. Port-injected fuel flow was controlled by varying injector pulse width and throttle position was adjusted manually to maintain testing mode parameters. Heated ethanol, unheated ethanol, and diesel only operating modes were run over a modified ISO 8178 eight-point test plan. Fumigant energy fraction (FEF), defined as the amount of energy provided by the fumigant based on the lower heating value (LHV) divided by the total fuel energy, up to 37% was achieved in the experiments. Ethanol fuel rail heat exchanger effectiveness decreased with increasing FEF and log-mean temperature difference (LMTD) increased. These opposite effects were likely due to dimensional design constraints of the heat exchanger limiting the heat transfer. Experiments found that with increasing FEF, engine NO emissions decreased, whereas NO2, CO, THC, and ethanol emissions increased. NO emissions reductions were countered by increasing NO2, resulting in constant NOX emissions. Soot concentrations produced varying trends, but with a tendency to decrease overall at high FEF. Preheating the ethanol with circulated engine coolant yielded few benefits to engine out-emissions. This study showed that the dual-fuel heated PFI rail system provided modest emissions benefits over diesel-only operation. Preheating the liquid ethanol was not as successful as anticipated because ethanol’s high latent heat of vaporization dominated over the sensible heat required to heat the liquid prior to the injectors.
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    Impacts of ethanol plants on highway networks
    (Journal of Transport and Land Use, 2011) Mitra, Subhor; Dybing, Alan; Tolliver, Denver
    This paper describes the impacts of the ethanol industry on existing highway infrastructure in the vicinity of an ethanol production plant. To determine the impacts of plant location, the corn and soybean draw areas are estimated on the basis of crop prices. Crop production data are extracted from satellite imagery of the crop data layer produced by National Agricultural Statistics Service and the United States Department of Agriculture. The increase in truck traffic attributable to the ethanol plant is estimated for the changed flow of feedstock. A model is run for two scenarios: i) existing corn and soybean production; and, ii) increased corn and soybean production. Based on existing pavement condition and incremental traffic changes, the funds required to maintain the affected roads at their present service levels are quantified.
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    Investigation Of Piston Geometry In Rapid Compression Machines And Sampling Methods For Internal Combustion Engines
    (2019-07) Dasrath, Dereck
    There is a growing effort to reduce carbon dioxide (CO2) emissions produced by internal combustion (IC) engines as an effort to curb anthropogenic climate change. The transportation sector accounts for 28% of anthropogenic CO2, motivating fundamental combustion research to understand and develop more efficient advanced combustion modes. Study of ignition delay time, autoignition pressure and temperature, the chemistry of fuel mixtures, and speciation of combustion products provide important insights into phenomena like pre-ignition (knock) and pollutants (CO2, oxides of nitrogen, soot, etc.) from modern-day IC engines. This body of work investigates novel speciation methods for studying combustion products from IC engines and unique piston geometries for rapid compression machines (RCMs). Quantifying combustion products is an important step in creating accurate numerical models for engine combustion. Many groups have used various instruments in conjunction to characterize a range of combustion generated hydrocarbons but few have used instruments in tandem to improve speciation methods during unconventional combustion modes and address the issues associated with off-line speciation. The first part of this thesis presents an investigation that quantified light unburned hydrocarbons (UHC) using a combination of Fourier transform infrared (FT-IR) spectroscopy and gas chromatography-mass spectroscopy (GC-MS). A light-duty diesel engine is used to generate hydrocarbons at various exhaust gas recirculation (EGR) levels and partially premixed low-temperature combustion (LTC) modes. Exhaust samples are extracted with a novel fixed-volume sampling system and sent into a gas chromatograph (GC) while minimizing unknown dilution, light unburned hydrocarbons (LHC) losses, and removing heavy unburned hydrocarbons (HHC). Along with the wide range of LHCs quantified in this study, focus is directed towards the problem of misidentification of propane by the FT-IR during LTC modes. In the region commonly identified as the absorption spectra of propane (2700 and 3100 cm-1), analysis of the FT-IR spectra indicates absorption band interference caused by components found in unburnt diesel fuel. One of the primary findings of this work is that GC-MS can aid in FT-IR spectral analysis to further refine FT-IR methods for real-time measurement of unconventional combustion mode exhaust species. Rapid compression machines (RCMs) and rapid compression and expansion machines (RCEMs) are apparatuses that have the ability to operate at engine-relevant conditions to study fuel autoignition and pollutant formation. These machines are currently limited for use in speciation studies due to thermal and mixture inhomogeneities caused by heat transfer and gas motion during compression. Studies have shown the disadvantages of using common flat and enlarged piston crevice designs for sampling reaction chamber gases during and after combustion. For instance, computer fluid dynamics (CFD) simulations performed by numerous groups, including collaborators on this work, have confirmed that unburnt fuel mixture emerges from the enlarged crevice after compression then subsequently mixes with reaction chamber gases during RCM and RCEM operation. This disadvantage renders whole-cylinder sampling techniques inaccurate for quantifying combustion products and reduces the relevance of RCMs and RCEMs for comparison with IC engines. Complex fast-sampling systems are implemented by a number of research groups to extract small quantities of gas from the center of the chamber before mixing occurs. Drawbacks with this approach include small sample volumes, local composition non-uniformities, and non-uniform progression of chemical kinetics during sampling. Experimental and computational studies emphasize the importance of piston design for the formation of a well-mixed, homogeneous core gas inside RCM and RCEM reaction chambers. In the second part of this thesis, a novel piston containing a bowl-like geometry similar to those used in diesel engines is implemented to overcome thermal and compositional non-uniformities within RCMs/RCEMs. By eliminating the enlarged crevice and introducing squish flow with the bowl piston, CFD studies show increased thermal uniformity for both RCM and RCEM trajectories. Experiments to characterize piston performance includes flat, enlarged crevice, and bowl piston profiles and four fuel mixtures using the University of Minnesota – Twin Cities controlled trajectory RCEM (CT-RCEM). Heat release analysis (HRA) indicates greater combustion efficiencies when using the bowl piston opposed to the standard flat and enlarged creviced pistons. This is indicative of smaller fractions of unburnt fuel left in the combustion chamber after combustion, ideal for dump sampling and the differentiation of unburnt fuel from combustion products during speciation. Ignition analysis for the bowl piston derived stronger ignition characteristics than the enlarged crevice and flat piston designs. As a result of stronger ignition and better uniform burning, the amount of fuel converted to products of combustion is increased.
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    A Spoonful of Sugarcane Ethanol: A Green Tax Medicine for the Cellulosic Ethanol Industry
    (Minnesota Journal of Law, Science and Technology, 2014-05) Huang, Ke
    On July 31, 2013, INEOS Bio, a bioenergy company, announced that its Florida facility became the world pioneer in producing commercial-scale cellulosic ethanol. Ethanol, or ethyl alcohol, is a renewable fuel resulting from fermenting plant-based materials. INEOS Bio produces cellulosic ethanol using vegetative and yard waste. Despite the flurry that accompanied last July’s event, Brazil is still regarded as the country that implemented the most successful ethanol industry in the world —the sugarcane ethanol industry. In the United States, the ethanol industry touches on two critical areas. First, ethanol can be used as motor fuel, and it is no secret that the United States relies on motor fuel. Second, the nation’s reliance on motor fuel, especially gasoline, raises significant environmental concerns, notably, greenhouse gas (GHG) emissions. Thus, given the recent advancements in ethanol production, and the critical areas that ethanol touches on, an issue emerges as to whether Brazil’s ethanol policy model can be instructive to the United States’ fledgling cellulosic ethanol industry. This Note seeks to suggest changes to the tax benefits of the U.S. cellulosic ethanol industry. This Note argues, primarily by focusing on federal tax policies and environmental effects linked with ethanol, (1) the trajectory of the United States’ corn and cellulosic ethanol industries; and (2) the trajectory of Brazil’s sugarcane ethanol industry. This Note then (1) reviews the relevant existing literature addressing ethanol; (2) compares and contrasts the federal ethanol tax benefits of the United States’ and Brazil’s ethanol industries; (3) compares and contrasts these industries’ impact on the respective country’s environment; and (4) explains why Brazil’s tax benefits should encourage the United States to implement similar benefits. This Note concludes that revising some of the U.S. cellulosic ethanol tax benefits, following Brazil’s ethanol industry tax benefits, will likely spur the U.S. cellulosic ethanol industry, which would ultimately result in significant environmental benefits.