Design, Construction, and Validation of an Atmospheric Combustor for Alternative Fuel Studies

An atmospheric combustion apparatus was designed through several iterations for Bucknell University's combustion laboratory. The final design required extensive fine-tuning of the fuel and air systems and repeated tests to arrive at a satisfactory procedure to transfer from gaseous to liquid fuel operation. Measurement of exhaust emissions were obtained under tests of gaseous methane and liquid heptane were operation in order to validate the functionality of the combustion apparatus, the fuel transition procedure, and emissions analyzer systems. The emission concentrations of CO, CO2, NOx, 02, S02, and unburned hydrocarbons from a multianalyzer and HFID analyzer were obtained for a range of equivalence ratios. The results verify the potential for future alternative fuel tests and illuminate necessary alterations for further liquid fuel studies.

Design and Use of an Alternative Fuel Testing Apparatus and Assessment of the Feasibility of Biodiesel

Petroleum supply and environmental pollution issues constantly increase interest in renewable low polluting alternative fuels. Published test results show decreased pollution with similar power output and fuel consumption from Internal Combustion Engines (ICE) burning alternative fuels. More specifically, diesel engines burning biodiesel derived from plant oils and animal fats not only reduce harmful exhaust emissions but are renewable and environmentally friendly. To validate these claims and assess the feasibility of alternative fuels, independent engine dynamometer and emissions testing was performed. A testing apparatus capable of making relevant measurements was designed, built, and used to test and determine the feasibility of biodiesel. The apparatus marks the addition of a valuable testing tool to the University and provides a foundation for future experiments. This thesis will discuss the background of biodiesel, testing methods, design and function of the testing apparatus, experimental results, relevant calculations, and conclusions.

Application of multi-criteria decision making methods to compression ignition engine efficiency and gaseous, particulate and greenhouse gas emissions

Compression ignition (CI) engine design is subject to many constraints which presents a multi-criteria optimisation problem that the engine researcher must solve. In particular, the modern CI engine must not only be efficient, but must also deliver low gaseous, particulate and life cycle greenhouse gas emissions so that its impact on urban air quality, human health, and global warming are minimised. Consequently, this study undertakes a multi-criteria analysis which seeks to identify alternative fuels, injection technologies and combustion strategies that could potentially satisfy these CI engine design constraints. Three datasets are analysed with the Preference Ranking Organization Method for Enrichment Evaluations and Geometrical Analysis for Interactive Aid (PROMETHEE-GAIA) algorithm to explore the impact of 1): an ethanol fumigation system, 2): alternative fuels (20 % biodiesel and synthetic diesel) and alternative injection technologies (mechanical direct injection and common rail injection), and 3): various biodiesel fuels made from 3 feedstocks (i.e. soy, tallow, and canola) tested at several blend percentages (20-100 %) on the resulting emissions and efficiency profile of the various test engines. The results show that moderate ethanol substitutions (~20 % by energy) at moderate load, high percentage soy blends (60-100 %), and alternative fuels (biodiesel and synthetic diesel) provide an efficiency and emissions profile that yields the most “preferred” solutions to this multi-criteria engine design problem. Further research is, however, required to reduce Reactive Oxygen Species (ROS) emissions with alternative fuels, and to deliver technologies that do not significantly reduce the median diameter of particle emissions.

Investigation of the chemical and physical basis of oxidative stress generated by particulate matter using the profluorescent probe technique

Following the growing need for adoption of alternative fuels, this project aimed at getting more information on the oxidative potential of biodiesel particulate matter. Within this scope, the physical and chemical characteristics of biodiesel PM were analysed which lead to identification of reactive organic fractions. An in-house developed proflurescent nitroxide probe was used. This project further developed in-depth understanding of the chemical mechanisms following the detection of the oxidative potential of PM. This knowledge made a significant contribution to our understanding of processes behind negative health effects of pollution and enabled us to further develop new techniques to monitor it.

The influence of fatty acid methyl ester profiles on inter-cycle variability in a heavy duty compression ignition engine

With the advent of alternative fuels, such as biodiesels and related blends, it is important to develop an understanding of their effects on inter-cycle variability which, in turn, influences engine performance as well as its emission. Using four methanol trans-esterified biomass fuels of differing carbon chain length and degree of unsaturation, this paper provides insight into the effect that alternative fuels have on inter-cycle variability. The experiments were conducted with a heavy-duty Cummins, turbo-charged, common-rail compression ignition engine. Combustion performance is reported in terms of the following key in-cylinder parameters: indicated mean effective pressure (IMEP), net heat release rate (NHRR), standard deviation of variability (StDev), coefficient of variation (CoV), peak pressure, peak pressure timing and maximum rate of pressure rise. A link is also established between the cyclic variability and oxygen ratio, which is a good indicator of stoichiometry. The results show that the fatty acid structures did not have a significant effect on injection timing, injection duration, injection pressure, StDev of IMEP, or the timing of peak motoring and combustion pressures. However, a significant effect was noted on the premixed and diffusion combustion proportions, combustion peak pressure and maximum rate of pressure rise. Additionally, the boost pressure, IMEP and combustion peak pressure were found to be directly correlated to the oxygen ratio. The emission of particles positively correlates with oxygen content in the fuel as well as in the air-fuel mixture resulting in a higher total number of particles per unit of mass.

The influence of oxygenated organic aerosols (OOA) on the oxidative potential of diesel and biodiesel particulate matter

Generally, the magnitude of pollutant emissions from diesel engines running on biodiesel fuel is ultimately coupled to the structure of respective molecules that constitutes the fuel. Previous studies demonstrated the relationship between organic fraction of PM and its oxidative potential. Herein, emissions from a diesel engine running on different biofuels were analysed in more detail to explore the role different organic fractions play in the measured oxidative potential. In this work, a more detailed chemical analysis of biofuel PM was undertaken using a compact Time of Flight Aerosol Mass Spectrometer (c-ToF AMS). This enabled a better identification of the different organic fractions that contribute to the overall measured oxidative potentials. The concentration of reactive oxygen species (ROS) was measured using a profluorescent nitroxide molecular probe 9-(1,1,3,3-tetramethylisoindolin-2-yloxyl-5-ethynyl)-10-(phenylethynyl)anthracene (BPEAnit). Therefore the oxidative potential of the PM, measured through the ROS content, although proportional to the total organic content in certain cases shows a much higher correlation with the oxygenated organic fraction as measured by the c-ToF AMS. This highlights the importance of knowing the surface chemistry of particles for assessing their health impacts. It also sheds light onto new aspects of particulate emissions that should be taken into account when establishing relevant metrics for assessing health implications of replacing diesel with alternative fuels.

Technoeconomic analysis of an integrated microalgae photobioreactor, biodiesel and biogas production facility

As fossil fuel prices increase and environmental concerns gain prominence, the development of alternative fuels from biomass has become more important. Biodiesel produced from microalgae is becoming an attractive alternative to share the role of petroleum. Currently it appears that the production of microalgal biodiesel is not economically viable in current environment because it costs more than conventional fuels. Therefore, a new concept is introduced in this article as an option to reduce the total production cost of microalgal biodiesel. The integration of biodiesel production system with methane production via anaerobic digestion is proved in improving the economics and sustainability of overall biodiesel stages. Anaerobic digestion of microalgae produces methane and further be converted to generate electricity. The generated electricity can surrogate the consumption of energy that require in microalgal cultivation, dewatering, extraction and transesterification process. From theoretical calculations, the electricity generated from methane is able to power all of the biodiesel production stages and will substantially reduce the cost of biodiesel production (33% reduction). The carbon emissions of biodiesel production systems are also reduced by approximately 75% when utilizing biogas electricity compared to when the electricity is otherwise purchased from the Victorian grid. The overall findings from this study indicate that the approach of digesting microalgal waste to produce biogas will make the production of biodiesel from algae more viable by reducing the overall cost of production per unit of biodiesel and hence enable biodiesel to be more competitive with existing fuels.

Vaporization dynamics of functional droplets in a hot laminar air jet

The vaporization characteristics of pendant droplets of various chemical compositions (like conventional fuels, alternative fuels and nanosuspensions) subjected to convective heating in a laminar air jet have been analyzed. Different heating conditions were achieved by controlling the air temperature and velocity fields around the droplet. A hybrid timescale has been proposed which incorporates the effects of latent heat of vaporization, saturation vapor pressure and thermal diffusivity. This timescale in essence encapsulates the different parameters that influence the droplet vaporization rate. The analysis further permits the evaluation of the effect of various parameters such as surrounding temperature, Reynolds number, far-field vapor presence, impurity content and agglomeration dynamics (nanosuspensions) in the droplet. Flow visualization has been carried out to understand the role of internal recirculation on the vaporization rate. The visualization indicates the presence of a single vortex cell within the droplet on account of the rotation and oscillation of the droplet due to aerodynamic load. External heating induced agglomeration in nanofluids leads to morphological changes during the vaporization process. These morphological changes and alteration in vaporization behavior have been assessed using high speed imaging of the diameter regression and Scanning Electron Microscopy images of the resultant precipitate. (C) 2012 Elsevier Ltd. All rights reserved.

Review on atomization and sprays of biofuels for IC engine applications

Ever increasing energy requirements, environmental concerns and energy security needs are strongly influencing engine researchers to consider renewable biofuels as alternatives to fossil fuels. Spray process being important in IC engine combustion, existing literature on various biofuel sprays is reviewed and summarized. Both experimental and computational research findings are reviewed in a detailed manner for compression ignition (CI) engine sprays and briefly for spark ignition (SI) engine sprays. The physics of basic atomization process of sprays from various injectors is included to highlight the most recent research findings followed by discussion highlighting the effect of physico-chemical properties on spray atomization for both biofuels and fossil fuels. Biodiesel sprays are found to penetrate faster and haw narrow spray plume angle and larger droplet sizes compared to diesel. Results of analytical and computational models are shown to be useful in shedding light on the actual process of atomization. However, further studies on understanding primary atomization and the effect of fuel properties on primary atomization are required. As far as secondary atomization is concerned, changes in regimes are observed to occur at higher air-jet velocities for biodiesel compared to those of diesel. Evaporating sprays revealed that the liquid length is longer for biodiesel. Pure plant oil sprays with potential use in CI engines may require alternative injector technology due to slower breakup as compared to diesel. Application of ethanol to gasoline engines may be feasible without any modifications to port fuel injection (PFI) engines. More studies are required on the application of alternative fuels to high pressure sprays used in Gasoline Direct Injection (GDI) engines.

Decarbonising urban transportation

18 p.

Catalisadores à base de Mg/La e de Al/La para a produção de biodiesel a partir de óleos refinados e ácidos

A crescente preocupação com a preservação do meio ambiente aliada às perspectivas de esgotamento das fontes de energia obtidas dos combustíveis fósseis tem impulsionado a indústria a desenvolver combustíveis alternativos a partir de recursos renováveis e processos ambientalmente não agressivos. O biodiesel, uma mistura de ésteres de ácidos graxos obtida pela transesterificação catalítica de óleos vegetais com álcoois de cadeia curta (metanol ou etanol) é um combustível alternativo importante, pelo fato das suas propriedades (índice de cetano, conteúdo energético e viscosidade) serem similares às do diesel obtido a partir do petróleo. No presente trabalho, a transesterificação do óleo de soja com metanol para a produção de biodiesel foi estudada em presença de catalisadores sólidos à base de Mg/La e Al/La com propriedades ácido-básicas. Catalisadores de Mg/La com uma relação molar Mg/La igual a 9:1 foram preparados por coprecipitação utilizando três métodos que se diferenciavam quanto ao tipo de agente precipitante e a temperatura de calcinação. O catalisador preparado com (NH4)2CO3/NH4OH como agente precipitante e calcinado a 450 C apresentou as melhores características físico-químicas e catalíticas. Catalisadores à base de Mg/La e Al/La com diferentes composições químicas foram sintetizados nas condições de preparo selecionadas. O comportamento catalítico destes materiais foi investigado frente à reação de transesterificação do óleo de soja com metanol. O catalisador de Al/La com uma relação molar Al/La igual a 9:1 mostrou o melhor desempenho catalítico (rendimento em ésteres metílicos igual a 84 % a 180 C) e pode ser reutilizado por pelo menos três ciclos de reação. Também foram realizados testes catalíticos na presença do óleo de soja com 10 % de ácido oleico verificando-se que os catalisadores utilizados possuem sítios capazes de catalisar as reações de transesterificação e esterificação

Effects of ethanol on vehicle energy efficiency and implications on ethanol life-cycle greenhouse gas analysis.

Bioethanol is the world's largest-produced alternative to petroleum-derived transportation fuels due to its compatibility within existing spark-ignition engines and its relatively mature production technology. Despite its success, questions remain over the greenhouse gas (GHG) implications of fuel ethanol use with many studies showing significant impacts of differences in land use, feedstock, and refinery operation. While most efforts to quantify life-cycle GHG impacts have focused on the production stage, a few recent studies have acknowledged the effect of ethanol on engine performance and incorporated these effects into the fuel life cycle. These studies have broadly asserted that vehicle efficiency increases with ethanol use to justify reducing the GHG impact of ethanol. These results seem to conflict with the general notion that ethanol decreases the fuel efficiency (or increases the fuel consumption) of vehicles due to the lower volumetric energy content of ethanol when compared to gasoline. Here we argue that due to the increased emphasis on alternative fuels with drastically differing energy densities, vehicle efficiency should be evaluated based on energy rather than volume. When done so, we show that efficiency of existing vehicles can be affected by ethanol content, but these impacts can serve to have both positive and negative effects and are highly uncertain (ranging from -15% to +24%). As a result, uncertainties in the net GHG effect of ethanol, particularly when used in a low-level blend with gasoline, are considerably larger than previously estimated (standard deviations increase by >10% and >200% when used in high and low blends, respectively). Technical options exist to improve vehicle efficiency through smarter use of ethanol though changes to the vehicle fleets and fuel infrastructure would be required. Future biofuel policies should promote synergies between the vehicle and fuel industries in order to maximize the society-wise benefits or minimize the risks of adverse impacts of ethanol.

直接甲醇燃料电池甲醇替代燃料的研究

论文主要研究了直接甲醇燃料电池（DMFC）中三种甲醇替代燃料，二甲氧基甲烷（DMM）、乙醇和乙二醇及导致阳极催化剂中毒的吸附CO（COad）在光滑R电极及几种新的R基催化剂电极上的电氧化行为。结合对催化剂的X射线光电子能谱（xPS）、X衍射(XRD)、扫描电子显微镜（SEM）和热重分析（TG）表征，初步探讨了几种新催化剂对三种甲醇替代燃料的电催化活性要高于碳载R（PtC）催化剂的原因。另外，还研究了用表面活化处理来提高阳极催化剂对甲醇氧化的电催化活性的方法。本论文得到的主要结果如下：1．在研究DMM在不同条件下，在不同R基催化剂电极上的电化学氧化行为的基础上，发现碳载R和TiO2（Pt-TiO2／C）复合催化剂对DMM氧化的电催化活性要优于Pt/C电极。而Pt-TiO2／C催化剂在吸附Ho3+(Pt-TiO2-Ho3+/C)或Eu3＋（Pt-TiO2-Eu3＋/C）后，对DMM氧化的电催化活性比Pt-TiO2／C电极高。表明TiO2、Eu3+和Ho3+对DMM的氧化都有很好的促进作用，这主要是它们都能为DMM的氧化在电极表面提供更多的含氧物种。由于DMM本身在这些催化剂电极上的氧化性能不好，而且DMM容易在酸性溶液中水解，生成甲醇和甲醛，因此，DMM不是一种好的甲醇替代燃料。2．无论在中性介质中还是在酸性介质中，Eu3＋和Ho3＋对乙醇在R／C电极上的电化学氧化反应都有较好的促进作用，而Eu3＋的促进作用要大于H3+，Eu3＋和H3+在酸性溶液中的促进作用要大于在中性溶液中。无论是中性溶液还是酸性溶液中，吸附CO（COad）在Pt／C催化剂电极上在较正的电位处有一个很大的氧化峰，而在R-Eu3＋／C或R-H3＋／C催化剂电极上在较负电位处有两个小的氧化峰，表明吸附的Eu3＋和Ho3+对cood在R／C催化剂电极上的氧化都有很好的促进作用，主要表现在使Cood的吸附强度降低和吸附量减少。XPs测量表明，当R／C电极表面吸附了Eu3＋或H了十后，使催化剂中Pt和c土的电子云密度变小，因此使Pt对coad的吸附强度减弱。由于Eu3＋或H03＋在电极上吸附不是物理吸附，而是化学吸附，因此，它们与Pt的结合具有相对的稳定性。乙醇电氧化的中间产物，如COad等能强烈地吸附在R上，因此会使R中毒。而Eu3＋或H矿"能降低Coad在R上地吸附强度，因此，Eu3＋或H3+能促进乙醇在Pt／C电极上的电化学氧化反应。Pt-TiO2／C催化剂对乙醇氧化的电催化活性要高于R／C催化剂，表明TiO2对乙醇在R／C电极上的电化学氧化反应也有较好的促进作用。XPS的测量表明，TiO2的加入并不改变Pt的电子状态，因此，TiO2能促进乙醇电氧化反应的主要原因是TIOZ能为乙醇氧化提供含氧物种。实验结果表明，Eu3＋或H3+对乙醇在R-TiO2／C电极上的电化学氧化反应也有一定的促进作用。这是由于Eu3＋或H3+改变了R的电子状态，降低了乙醇电氧化中间产物，COod在Pt上的吸附强度，而TIOZ提供了COod的氧化所必须的含氧物种。3．无论是酸性溶液中还是中性溶液中，乙二醇在R-TiO2／C电极上的氧化活性比在R／C电极上高。这表明TIOZ能促进乙二醇在Pt上的电氧化反应。进一步的实验表明，TIOZ对COad在Pt催化剂电极上氧化的促进作用并不明显。XPS测量表明，这是由于TIOZ并不改变R的电子状态。所以，TiO2对乙二醇在Pt上的电氧化的促进作用只是基于提供乙二醇电氧化所需的含氧物种。无论是酸性溶液中还是中性溶液中，乙二醇在R-WO3／C电极上的氧化活性都比在R／C电极上高。这表明W03能促进乙二醇在R上的电氧化反应。进一步的实验表明，R-WO3／C电极对Coad氧化的电催化活性也要高于R／C电极，XPS测量表明，WO3会降低Pt的电子云密度。所以，WO3对乙二醇在R上的电氧化的促进作用除了提供含氧物种外，还由于它能降低R的电子云密度而降低了乙二醇电氧化中间产物。4．用四氢吠喃和丙酮混合溶液浸泡法对电极进行表面处理后能使Pt／C和Pt-WO3／C电极对乙醇和乙二醇氧化的电催化活性有很大的提高。其原因可能是Pt／C和Pt一w03／C电极在经表面处理后，在电极制备过程中带来的表面活性剂等杂质由于溶解在混合溶液中而被除去，Nafion也可能在用混合溶液浸泡后会发生一定程度的结构变化，因此，使活性中心的位点增加，从而增加了催化剂的电催化活性。另外，经表面处理后，Pt／C和Pt-WO3／C电极的活性中心的结构有一定的变化，使COad的吸附强度降低而容易氧化，降低了COad对催化剂的毒化作用，因而提高了电极对乙醇和乙二醇氧化的电催化活性。

Seeing the forest for the fuel

We demonstrate a new approach to understanding the role of fuelwood in the rural household economy by applying insights from travel cost modeling to author-compiled household survey data and meso-scale environmental statistics from Ruteng Park in Flores, Indonesia. We characterize Manggarai farming households' fuelwood collection trips as inputs into household production of the utility yielding service of cooking and heating. The number of trips taken by households depends on the shadow price of fuelwood collection or the travel cost, which is endogenous. Econometric analyses using truncated negative binomial regression models and correcting for endogeneity show that the Manggarai are 'economically rational' about fuelwood collection and access to the forests for fuelwood makes substantial contributions to household welfare. Increasing cost of forest access, wealth, use of alternative fuels, ownership of kerosene stoves, trees on farm, park staff activity, primary schools and roads, and overall development could all reduce dependence on collecting fuelwood from forests. © 2004 Cambridge University Press.

Performance and characteristics of platinum, palladium/rhodium and palladium automotive catalysts when subjected to ethanol, acetaldehyde and a synthetic E85 exhaust gas mixture

The performance optimisation of automotive catalysts has been the focus of a great deal of research for many years as the automotive industry has endeavored to reduce the emission of toxic and pollutant gases generated from internal combustion engines. Just as the emissions from diesel and gasoline combustion vary so do the emissions from combustion of alternative fuels such as ethanol; the variation is in both quantity and chemical composition. In particular, when ethanol is contained in the fuel, ethanol and acetaldehyde are present in the exhaust gas stream and these are two compounds which the catalytic converter has not traditionally been designed to manage. The aim of the study outlined in this paper was to assess the performance of various catalyst formulations when subjected to a representative ethanol exhaust gas mixture. Three automotive catalytic converter formulations were tested including a fully Pt sample, a PdRh three-way catalyst sample and a fully Pd sample. Initially the samples were tested using single component hydrocarbon light-off tests followed by a set of tests with carbon monoxide included as an inlet gas to observe its effect on each individual hydrocarbon oxidation. Finally, each formulation was tested using a full E85 exhaust gas mixture. The study was carried out using a synthetic gas reactor along with FTIR and FID exhaust gas analysers. All formulations showed selectivity toward acetaldehyde formation from ethanol dehydrogenation which resulted in negative acetaldehyde conversion across each of the samples during the mixture tests. The fully Pt sample was the most detrimentally affected by the introduction of carbon monoxide into the gas feed. The Pd and PdRh samples exhibited a tendency toward acetaldehyde decomposition resulting in methane and carbon monoxide formation. The Pt sample did not form methane but did form ethylene as a result of ethanol dehydration.