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In previous studies on a single-cylinder IDI diesel engine and a V-8 DI turbo diesel engine, significant reductions in particulate matter emissions were observed with the blends of glycol ethers in diesel fuel. In this study, experiments on the effects of oxygenated fuels on emissions and combustion were performed in a 4-cylinder TDI diesel engine. A blend of 20 wt % monoglyme and 80 wt % diglyme, referred to as CETANER, has been examined as a diesel reformulating agent. Blend ratios were considered to provide approximately 2, 4, and 6 wt % oxygen to lowsulfur diesel fuel. Gaseous and particulate emission measurements, as well as heat release rate analysis, have been used to address how emissions and combustion scale with increasing weight percent oxygen in the fuel. The results demonstrate that the oxygenated fuel provides significant reduction in particulate matter with a small penalty on NO x emission, especially at high load. This oxygenated fuel effect may result from an enhanced concentration of oxygen atoms in the over-rich mixture thereby contributing to soot suppression and thermal NO x formation through a shift to a leaner mixture. Low load results imply that the combined effect of relatively high exhaust gas recirculation (EGR) ratio and oxygen addition contributes to both NO x and soot reduction through a combination of flame temperature decrease and suppression of soot precursors. The combined effects on thermal NO x reduction at low load appear to be confirmed by heat release analysis, which indicates a small reduction in premixed burn peak and in-cylinder pressure. The slight reduction in HC and CO emissions under most conditions indicates an improvement of combustion efficiency with the use of oxygen addition. This result also represents the potential of diesel reformulation coupled with high EGR ratio for a better particulate/NO x tradeoff. Particulate morphology, as seen in transmission electron microscopy (TEM) micrographs, shows that enhanced oxidation of unburned hydrocarbon due to oxygen addition leaves a less agglomerated particulate structure especially at low mode, leading to a higher number density of smaller particles and a lower particulate mass.

Vegetable oils can contribute toward the goal of energy independence and security due to their naturally renewable resource. They are promising candidates as base fluids for ecofriendly lubricants because of their excellent lubricity, biodegradability, good viscosity−temperature characteristics, and low evaporation loss. Their use, however, is restricted due to low thermo-oxidative stability and poor cold-flow behavior. This paper presents a systematic approach to improve their oxidation behavior by searching for a suitable additive combination. The study of antioxidant/antiwear additive synergism was investigated on a set of four antioxidants and three antiwear additives in vegetable oils using pressure differential scanning calorimetry (PDSC) and a rotary bomb oxidation test (RBOT). The results indicate that dialkyldithiocarbamate antioxidant performed better than diphenylamine and hindered phenol. The zinc dialkyldithiocarbamate antioxidant showed excellent synergism with antiwear additive antimony dithiocarbamates.

Due to the global drive towards biodegradable products, trimethylolpropane [2-ethyl-2-(hydroxymethyl)-1,3-propanediol] (TMP) esters based on palm and palm kernel oils were synthesized, their lubrication properties evaluated, and their potential as base stock for biodegradable lubricants assessed. Two types of TMP esters were considered: palm kernel (PKOTE) and palm oil (PPOTE) TMP esters, derived from palm oil and palm kernel methyl esters, respectively. Lubrication properties such as viscosity, viscosity index (VI) and pour point (PP) were determined according to methods of the American Society for Testing and Materials. Wear and friction properties were evaluated using a four-ball test machine, while oxidative stability was studied with the Penn State Micro-oxidation thin-film test. High VI ranges between 170 to 200 were recorded for these base stocks. PP were relatively high, between 4 to -1 °C, but were improved to at least -33 °C in high oleic palm oil TMP esters. The effects of chemical structure and impurities on wear properties and oxidative stability were also studied. The presence of methyl esters was found to improve wear, but hydroxyl groups in mono-and diesters had negative effects at high concentrations. Differences in chemical structures of PKOTE and PPOTE were shown to affect friction and wear results. Both base fluids exhibit oxidative stability comparable to other high oleic base fluids.Keywords: Biodegradable lubricant, palm oil, palm kernel oil, trimethylolpropane esters.Correspondence: Robiah Yunus, Department of Chemical and Environmental Engineering, Faculty of Engineering, University Putra Malaysia, 43400 UPM, Serdang, Selangor, Malaysia. Phone: +60-3-89466291/019-6969106, Fax: +60-3-86567099; e-mail: robiah@eng.upm.edu.my

The use of biodegradable lubricants in diverse applications continues to increase. Vegetable oils (e.g., soybean oil) are the main biodegradable lubricant base stocks used worldwide. However, there are concerns about their oxidative stability and low-temperature performance. Improvements in oxidative stability can be made through chemical or genetic modifications. This work compared the effects of oils with different chemical compositions. Soybean oil, high-oleic soybean oil, and epoxidized soybean oil were compared in laboratory bench tests. The tests conducted include the Penn State sequential four-ball wear test and the Penn State micro-oxidation test. Oxidation products from the micro-oxidation test were analyzed by FTIR and gel permeation chromatography. In this paper, all oils were evaluated neat, without additives.It is only natural that lubricant technology has advanced as a result of concerns for protecting and preserving the environment in all aspects of our lives. Research and development in lubricant technology to find better ways to protect the environment-or at least to reduce environmental pollutants-is driven by public demand, industry concerns, and governmental agency policies. The negative impact of the spillage or leakage of lubricants has led to the development of oils and greases that are less detrimental to the environment if inadvertently spilled or leaked.As a result of these growing environmental concerns, vegetable oils and their derivatives are finding their way into lubricants used in industrial and transportation applications. Vegetable oils can offer significant environmental advantages with respect to biodegradability and renewability, as well as satisfactory performance in a variety of applications. However, vegetable oils differ from traditional mineral or synthetic oils in that they are composed of TAG, which have different amounts and types of FA attached to the glycerol portion of the vegetable oil structure. The FA vary in the length of their hydrocarbon chains and degree of unsaturation (1). A direct consequence of this unique composition is that such oils oxidize much more rapidly than other lubricant base fluids because of the presence of double bonds. As a result, improving the oxidative stability of vegetable oils is a major objective. One approach used to improve their performance is to modify the FA structure either chemically or genetically (2).In this study, the oxidative and wear performance of oils were compared to better understand how the chemical composition of the base stock affects these properties. The oxidative stability of the base oils can be evaluated by different techniques. In this study, the Penn State micro-oxidation test (PSMO), a thin-film test used extensively to study the oxidative stability of mineral and synthetic oils, was selected. This relatively simple thin-film test requires a much smaller sample size than most oxidation tests; it is not oxygen-diffusion limited and requires relatively short test durations (3,4). The wear performance of the ...

SummaryOver several decades, site operations at what is now the U.S. Department of Energy's (DOE's) Idaho National Engineering and Environmental Laboratory have included nuclear reactor testing, reprocessing of spent nuclear fuel, and the storage, treatment, and disposal of the resultant radioactive and mixed wastes generated. Liquid, acidic, and radioactive high-level waste (HLW) and sodium bearing waste (SBW) from spent-fuel reprocessing operations have for the most part been calcined in the New Waste Calcining Facility (NWCF) and the earlier Waste Calcining Facility (WCF) to produce a dry granular waste form that is safer to store. However, about a million gallons of SBW remains uncalcined, and this liquid mixed waste, stored in tanks, does not meet current regulatory requirements for long-term storage and/or disposal. As a part of the Settlement Agreement between DOE and the State of Idaho, the tanks currently containing SBW are to be taken out of service by December 31, 2012, which requires the removal and treatment of the remaining SBW.Several potential options have been proposed for treating the SBW. Of those considered, vitrification received the highest weighted score against the criteria used. Beginning in fiscal year 2000, the INEEL HLW program embarked on a program for technology demonstration and development that would lead to conceptual design of a vitrification facility, based upon the liquid-fed melter technology, in the event that vitrification is the preferred alternative for SBW disposal. This program includes several separate activities that include, among others, waste-form development, process feed-stream design, and melter vitrification demonstration testing of the nonradioactive, surrogate SBW flowsheet. The first of the melter flowsheet tests conducted in support of INEEL's vitrification facility design is discussed below.The Pacific Northwest National Laboratory's (PNNL's) Research-Scale Melter (RSM) was used to conduct these initial melter-flowsheet evaluations. The RSM is a small (1/100-scale) joule-heated melter that is capable of processing melter feed on a continuous basis. This capability is key for:• developing/evaluating process flowsheets• characterizing relationships between feed composition and the properties of the final glass produced• establishing the fate and behavior of process effluent.This melter system's capability to produce glass in a continuous manner is also essential for estimating the behavior of a full-scale system. Moreover, the size of the RSM allows the impacts of process variables upon melter performance or glass quality to be quickly and efficiently evaluated without undue expense or waste generation.The experimental scope of this initial, 5-d, 120-h, SBW vitrification test was to evaluate the:• processing characteristics of the newly formulated SBW surrogate melter feed stream• acceptability of various SBW to glass-forming additive ratios• possible formation of a secondary sodium sulfate phase iv • effectiveness of sugar as a glass oxidation-state modifie...