Production Of Heavy Lubricating Oil Base Stocks And Analyses By Using A New Method HPLC

Abstract The main objective of the present investigative work is the experimental production of heavy lubricating oil base stocks and the study of the effect of chemical composition on physico-chemical characteristics of the prepared lube oil samples. In the first process, solvent dewaxing, the mixture of methyl ethyl ketone and methyl isobutyl ketone (MEK/MIBK) is used as a recent solvent in the dewaxing process to obtain a significant yield of low pour point products and to compare this mixture with MEK/toluene which is used in the industry process. Solvent dewaxing process is carried out at - 10°C using the mixture of MEK and MIBK (40/60 by wt.) with solvent oil ratio of 3:1 for the selected raffinates, heavy refined oils, from furfural and NMP extraction processes. The dewaxed oil samples were analysed to evaluate their physico-chemical characteristics by the standard methods outlined in ASTM, IP and UOP books such as the standard methods for wax content, pour point, sulfur content and structural group analysis by n-d-M method. The results show that the use of MEK/MIBK mixture instead of MEK/toluene at -10°C achieves an increase in filtration temperature with about 5°C with subsequent a reduction in the cooling rate of process. In the second process, clay-alumina finishing process as a percolation process, the dewaxed oil samples are treated to reduce the sulfur content and remove the nitrogen, oxygen and other undesirable compounds completely. The local natural clay (fuller's earth) with the particle size of 30–60 mesh and aluminum oxide 90 active neutral (Merck) with the particle size of 70–230 mesh are used as a mixture in this process. The finished lube oil samples are analysed to evaluate their physico-chemical characteristics by the standard methods outlined in ASTM, IP and UOP books. In addition, heavy grades are analysed by the high performance liquid chromatography (HPLC) after the solvent extraction and clay-alumina finishing processes. The chromatograms reveal the reduction in aromatic peaks after clayalumina finishing process and the reduction in saturate humps after the dewaxing process. Finally, the results show that high quality lube oils with good thermal and oxidation stabilities are produced.