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M.Tech. (Mechanical Engineering) / This study investigated process development of recovering base oils from waste lithium based lubricating grease using a novel combination of thermal degradation in an aqueous caustic solution and solvent extraction. Lubricating greases consist of a thickening agent dispersed in mineral or synthetic oil, forming a colloidal suspension [1]. Large and increasing volumes of used lubricating oil and grease are produced each year and are considered hazardous wastes. During operation, grease suffers mechanical and thermal degradation [2]. Subsequently, it is regarded as waste and it must be disposed. The waste oil should be collected and recycled not only to prevent the environmental pollution but also to preserve natural resources. Solvent extraction is the preferred method to recycle waste lubricants as it is cost-effective and requires no further purification of the product [3]. The influence of extraction temperature, agitation strength, extraction time, degrading agent concentration, degrading agent-to-grease and solvent-to-sludge mixing ratios on base oil recovery from waste lubricating grease was investigated. This study further optimised the process by studying the influence of various degrading agents (LiOH, NaOH and KOH) and solvents (n-hexane, toluene, heptane, butane, hexanol and acetone) on oil recovery. Oil recovery was enhanced by increase in both extraction temperature, time and agitation speed. The optimum extraction time was found to be 12 minutes. KOH was found to be the optimum degrading agent compared to LiOH and NaOH. Oil recovery also increased from 8.04% to 36.87% with increase in KOH m/m from 5% to 30%. The recovery also increased with an increase of solvent-to-sludge ratio up to 1:6. n-Hexane gave the highest recovery of 74.39% while acetone gave the lowest of 7.43%. A solvent recovery of 82.6% to 88% was obtained through fractional distillation. The study also investigated the differences between virgin and recycled oil using atomic absorption (AA), inductively coupled plasma (ICP) and Fourier transform infrared radiation (FTIR). Rheological studies of waste grease derived oil (WGDO) were also performed. ICP results showed traces of some elements such as Fe, Cu, Si, Ni and Al at a concentration of less than 0.9 mg/L. Oxidation was observed to occur at a band length of 1716 cm-1 while additives were identified at 1670 - 1725 cm-1. The oil viscosity slightly increased with increasing shear rate at temperatures between 60°C and 120°C. The shear rate was varied from 200 to 1000 1/s, with a viscosity convergence at 100°C. A financial economic model was applied to investigate the feasibility of the recycling technology. For 800 kg/day treatment plant, an investment of R 6,031,304.27 is required with a potential return on investment of 40%. Recovery was found to be favourable option compared to landfilling as it offers both economic and environmental benefits.

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Thesis (M.S.)--University of Akron, Dept. of Mechanical Engineering, 2008. / "December, 2008." Title from electronic thesis title page (viewed 12/9/2009) Advisor, Jiang John Zhe; Faculty Readers, Joan Carletta, Dane Quinn; Department Chair, Celal Batur; Dean of the College, George K. Haritos; Dean of the Graduate School, George R. Newkome. Includes bibliographical references.

M. Tech. Chemistry. / Methods developed for the analysis of used oil can play a vital role in monitoring the condition of engines and may help to improve overall equipment effectiveness. Quantification of trace elements in used lubricating oil forms a vital part in monitoring engine conditions and impact on the environment. The main objective of this work is to investigate methods used for the accurate determination of trace elements in lubricating oils. In this study, inductively coupled plasma-optical emission spectrometry (ICP-OES) was used for the determination of trace elements (Ag, Ba, Cu, Mn and Ni) in lubricating oils.

Investigations of new applications of the inductively coupled plasma (ICP) for analytical atomic emission spectroscopy are performed. Research efforts are focused in three major areas: emissions below 185 nm, analysis of wear metals in lubricating oils and use of the ICP as a selective detector for high performance liquid chromatography (HPLC). A unique plasma coolant tube containing a side arm which allows direct observation of the discharge is used to investigate emissions in the vacuum ultraviolet (VUV) spectral region between 120 and 185 nm. Emissions from elements which do not emit radiation in the visible region are observed. Oxygen emissions at 130 nm, nitrogen at 149 and 174 nm and carbon at 155 and 165 nm make up the background spectrum. These elements are present as impurities in the argon gas used to sustain the ICP discharge. Fifteen emission lines from bromine are observed. Those at 153 and 163 nm are the most intense. Sulfur also has fifteen emission lines and chlorine has nine in this region of the spectrum. The VUV region is found useful for observation and potential analysis of many elements. A heated sample introduction system attached to a Babington nebulizer is investigated as a means to aerosolize lubricating oils for introduction into the ICP. This allows direct analysis of wear metals in oil samples without requiring the usual sample dilutions. Several commercial brands and weights of motor oil are spiked with iron in order to evaluate this system. Heating the oil as it enters the nebulizer is found to increase the nebulization efficiency as much as sixtyfold in some cases. Differences in nebulization efficiency due to viscosity are almost entirely eliminated through the application of heat. A linear calibration curve extending three orders of magnitude from a detection limit of one ppm iron is determined. The ICP is used as a selective detector for HPLC. Nucleotides separated by anion exchange chromatography are determined in the ICP by observing phosphorus emissions. Methanol and acetonitrile used for reverse phase HPLC are successfully run in the IPC. The method is evaluated by using the ICP to determine phosphorus in compounds separated by using reverse phase conditions. The HPLC is used to separate organic interferences from several silicone samples using reverse phase conditions allowing the ICP to accurately analyze silicon content.

Thesis (M.S.)--West Virginia University, 2010. / Title from document title page. Document formatted into pages; contains xi, 150 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 97-101).

M.Sc. / Emulsions are not widely used in industry for wear-metal-in-oil determinations and this study was undertaken in order to evaluate such a possibility. The use of emulsified standards was compared to aqueous standards for the calibration of an emulsified used lubricating oil sample. The traditionally used methods of ashing in a muffle furnace and dilution with the organic solvent, xylene were also evaluated in comparison with the emulsion methodology. Inductively coupled plasma optical emission spectrometry (ICP-OES) was used for the wear-metal-in-oil analysis. The performance characteristics of each method were compared for the following metals: AI, Cr, Cu, Fe, Ni, and Pb. The used oil sample and emulsified standards were acid treated and emulsified in water {1% wlw) using tetralin as solvent and triton X-100 as surfactant. This evaluation included the calibration characteristics, precision and accuracy obtained, as well as the results of recovery studies. The emulsification method was found to be comparable to the ashing and dilution methods in terms of calibration and only Cr, Cu, Fe and Pb concentrations were found. The precision of the emulsification method was found, in general, to be close to or less than 2% RSD. The used oil matrix also contained leaked petroleum from a problem car engine. An accurate determination of lead was consequently impossible since the high lead content led to sedimentation. The use of the internal standard, indium, was evaluated for its effectiveness in correcting possible matrix effects that were evident from the results obtained in the recovery studies. The recovery studies showed the Cr and Pb determinations to be adversely affected by internal standardization. An alternative approach for matrix effect correction, the common analyte internal standardization (CAIS) method was also investigated. This method held promise for allowing the use of aqueous standards, instead of oil or emulsion standards, for the calibration of the emulsified oil samples. Three different applications of the CAIS technique were investigated and all proved unsuccessful.

Due to the fact that only comparative results were sought, the investigation was greatly simplified. On a comparative basis, the effects of external influences were largely eliminated from positions of vital importance and the use of an elaborate test, circuit was unnecessary. The equipment consisted of a high-voltage test transformer which supplied the test voltage; an induction regulator, auto transformer and generator field rheostats for voltage control; overload relay and aircore inductances for circuit protection; motor-generator set for a source of 60 cycle alternating voltage. The electrodes were circular, square edge brass discs. Specimens were immersed in lubricating oil for periods up to 40 hours and then tested for puncture strength. Following this, specimens were immersed for one hour and 24 hours and each of the two groups tested at intervals of time up to 720 hours. In each test the voltage was raised in steps of 200 volts, starting at 1000 volts. The puncture strength of the untreated paper was determined by testing a sufficient number of specimens over a period of days. The results obtained indicated no immediate deleterious effects of lubricating oil on paper. On the contrary, there was an improvement in puncture strength, accounted for by the fact that the relatively low voltages-used did not make ionization a serious factor. The results of tho long-time tests were unsatisfactory, as explained previously. However, they did permit the conclusion that deterioration of paper impregnated with lubricating oil would become apparent much sooner than if insulating oil were used. Oxidation, although probably existing, was apparently too slow to affect the results. / Master of Science

The original intention regarding the Reynolds’ Number Apparatus was to design, construct, and operate extensively the experimental machinery. The extensive operation of the apparatus, however, would entail not only the investigation of the effects of various conditions on the Reynolds’ number of liquids, but also the effects of laminar and turbulent flow on the heat transferred from the liquid to the pipe walls. It would also be possible to use the apparatus to determine the friction factors of various diameter pipes. Any one of the above subjects contains enough material for a thesis. It was therefore decided to limit the scope of this investigation to the design, construction, and calibration of the apparatus. In view of the extremely slow delivery of equipment and the many delays encountered during the construction, this was indeed a wise decision. It may therefore be stated that the purpose of this report is to present to the reader the Reynolds’ Number Apparatus and to acquaint him with its design, construction, calibration, and experimental possibilities. Although only enough test runs will be made to calibrate the instruments required to determine the Reynolds’ number of a given oil at one temperature, it is the author’s belief that this report will serve as an adequate guide to the construction of similar apparatuses and will stimulate others to a more extensive investigation of the experimental possibilities. / Master of Science