Characterisation and environmental effects of unresolved complex mixtures of hydrocarbons

Merged with duplicate record (10026.1/589) on 03.01.2017 by CS (TIS)This is a digitised version of a thesis that was deposited in the University Library. If you are the author please contact PEARL Admin ([email protected]) to discuss options.The gas chromatograms of crude oil hydrocarbons reveal both resolved and unresolved components. The unresolved feature is commonly referred to as the unresolved complex mixture (UCM). UCMs are thought to result from the co-elution of complex mixtures of hydrocarbons with similar chemical properties and become more obvious as resolved components are removed by processes such as weathering and refining. Consequently UCMs are a prominent feature in oil-polluted sediments, biodegraded crudes and refineiT products. The characterisation of both aliphatic and aromatic unresolved complex mixtures (UCMs) of hydrocarbons, as well as their possible effects on the environment, is described. An aliphatic hydrocarbon UCM isolated from the base oil of Silkolene 150 lubricating oil was characterised by a combination of micro vacuum-distillation and oxidative degradation. Vacuum-distillation produced six distillate cuts and a residue which were all highly unresolved by GC (ca. 951/6). The average molecular weight of each cut was determined by probe CIMS (310 - 440 Daltons), and varied by -20 Daltons. Cr03 oxidation of each fraction yielded similar distributions of n-monocarboxylic acids, ketones and lactones as well as C02 (ca. 6%). The resolved products of oxidation suggest that the aliphatic UCM is a rather homogeneous mixture of highly branched alkanes. However a significant amount of the products remain unresolved (UCMox.; ca. 70-95%). A retro -structural analysis approach, using an aromatic UCM oxidant (Ru04), combined with a mass balance approach, was used to characterise aromatic UCMs. Following reproducibility studies and the analysis of authentic aromatic compounds, the method was applied to the characterisation of unresolved aromatic refinery oil fractions and a suite of aromatic UCM distillate fractions. Selected refinery oils were separated into mono-, di-, tri- and tetraaromatics by BPLC and shown to be mainly unresolved by GC (ca. 80%). Ru04 oxidation of these fractions yielded DCM soluble products (24 - 74%), water soluble products (0 - 10%) and C02 (12 -78%). The principal resolved products in each oxidation were monocarboxylic acids and dicarboxylic acids which were used to reconstruct precursor compounds. Vacuum-distillation of Tia Juana Pesado crude (Venezuela) gave six cuts and a residue which were analysed by GC, 1H NMP, UV and probe CIMS to obtain molecular weight (171 - 301 Daltons) and broad structural information whilst Ru04 oxidation was used to obtain molecular information via the retro -structural analysis approach. This showed that the aromatic UCM was in fact highly aliphatic and contained alkyl and cycloalkyl tetralins. A significant advancement in the quantitative characterisation of UCMOx. and subsequently the characterisation of aromatic UCMs was made. Ion cyclotron resonance spectrometry (ICR) was used to characterise the Ru04 oxidation products of selected refinery fractions. Analysis of the oxidation products of a monoaromatic refinery fraction indicated the presence of monocarboxylic acids (Cl - C21; 58%) and alicyclic carboxylic acids (C7 - C19; 16%), a hydrogenated monoaromatic sample contained monocarboxylic acids (Cl - C20; 30%), dicarboxylic acids (C2 - C11,7%) and alicyclic carboxylic acids (C7 - C18; 11%) , whilst a diaromatic fraction contained monocarboxylic acids (C10 - C19; 7%), alkyl phthalic acids (C8 - C17', 17%) and cycloalkyl phthalic acids (C11 - C15; 3%). Retro -structural analysis suggests that the nonhydrotreated monoaromatic UCM is mainly comprised of alicyclic and alkyl substituted benzenes, the monoaromatic UCM isolated from the hydrotreated oil of alky'l and cycloalkyl substituted tetralins and the diaromatic fraction of alkyl and cycloalkyl naphthalenes. This was supported by, FIMS analysis of the fractions prior to oxidation. As an investigation of the environmental toxicity of UCMs, the effect of a saturated aliphatic UCM, and its chemical oxidation products, on the feeding rate of mussels (Mytilus edulis), was investigated. The UCM had little effect, whilst oxidation resulted in an increase in toxicity. The non-toxic nature of the hydrocarbons was attributed to their low aqueous solubility, whilst oxidation resulted in the formation of products NNith a greater solubility, which were sufficiently hydrophobic to be narcotic toxicants. Parts of this work have been published [Thomas et al., (1993) Organic Geochemistry, Falch Hurtigtrykk, Non%-ay(A bstract), 717-719; Thomas et al., (1995) [Vater Research. 29,371-382]. ivPCFC and Shell Researc

Advancements In Mechanical Sealing - API 682 Fourth Edition

TutorialAPI 682 is the leading document for mechanical seals in petrochemical, chemical, and pipeline services worldwide. It has combined the aspects of seal design, testing, standardization, and applications to provide the users and OEMs alike with a common source of information for mechanical seals. As seal technology has advanced, the standard has expanded to incorporate new seal designs, materials, seal selection guidance, and piping plans. Although the standard is not yet published, the final draft has been prepared and gives us notice of the upcoming requirements. This tutorial will cover the major changes introduced in the Fourth Edition

Advanced waste treatment of industrial waste waters by physicochemical processes

The primary objective of this investigation was to determine the general applicability of using physicochemical processes for treating different types of industrial wastes. Emphasis was placed on the evaluation of the treatment efficiency and the performance difficulties encountered in the treatment of each waste. Two types of waste were studied, one a high strength acidic industrial chemical waste and the other a petroleum refinery waste. The physicochemical system utilized included chemical coagulation and clarification plus activated carbon adsorption. Parallel operations of fixed-bed and expanded-bed carbon adsorbers were conducted. Treatment efficiencies were evaluated in terms of the removals of chemical oxygen demand, total organic carbon, turbidity, and inorganic nutrients. Because of the low suspended solids level contained in the acidic chemical waste, carbon adsorption was the only treatment needed for this waste. It was found that soluble organics were effectively removed from the chemical waste by carbon adsorption. Initial pH adjustments for the chemical waste to 3.2, 7.0, and 11.4 did not significantly affect the COD removal efficiency. Turbidity and nitrogen (total kjeldahl and ammonia-N) were removed to some extent by carbon adsorbers, while phosphorus (total and ortho-P) was totally unaffected. Treatment of the refinery waste used a combination of iron coagulation at a dosage of 2.50 mg/1 as FeCl₃[middot]6H₂O and 3 ft carbon column adsorption. Exceptionally high water quality having a TOC of less than 3 mg/1 and turbidity of less than 1 JTU was obtained. However, small quantities of organic leakage were observed consistently in all the carbon adsorber effluents. The nature of the nonadsorbable organic material was not established. Orthophosphate removal was effected by chemical coagulation while nitrogen (ammonia and organic-N) was not. Carbon adsorbers were not found to remove any of the inorganic nutrients from the refinery waste --Abstract, pages ii-iii

Resource Upgrading in Advanced Supercritical Fluid (Supercritical Fluid with Catalyst and Cosolvent): Liquid Fuels from Biomass in Sub and Supercritical Water and Carbohydrate Up-Conversion in Ionic Liquid and Supercritical Fluids Mixtures

Liquid fuels from biomass and up-conversion of biomass in advanced supercritical fluid are reviewed in this chapter. Lignin can be converted into heavy hydrocarbons in subcritical water extraction. Lipid, which is triglyceride, is catalytically converted into straight-chain hydrocarbons of free fatty acid (decarboxylation) formed by hydrolysis. Carbohydrate is also hydrothermally converted into furan ring compound and fatty acids. Protein is converted into amino acids in hydrothermal water and depolymerization of protein is favored with rapid heating and denaturation agency such as alkaline earth metals. Free amino acids are further decomposed into carboxylic acid through deamination and into amine through decarboxylation. To inhibit Maillard reactions, which result in polymerization, the deamination of amino acid at low temperature was favored and a solid catalyst was quite active for deamination of free amino acids at quite low temperature hydrothermal water. Cellulose was dissolved in some ionic liquids with high mass percentages (5–20 wt%) and converted into monomers and useful components such as furan ring compounds and supercritical fluid cosolvent such as hydrothermal water in ionic liquids supported improvement of reaction efficiency. For hydrogenation of biomass, it was confirmed that hydrogen solubility was enhanced with supercritical carbon dioxide and it must be helpful for hydrogen reaction with biomass molecule

GUIDELINES FOR REDUCING THE NOISE LEVEL OF A CENTRIFUGAL AIR COMPRESSOR INSTALLATION

TutorialThis paper will review the best practices for installation of a centrifugal air compressor without a sound enclosure to obtain the best acoustic environment for reduced operating noise levels. An overview of the noise sources associated with a centrifugal air compressor will be discussed along with the noise attenuation techniques. Moreover, proper selection and installation of accessory hardware associated with the compressor installation will be addressed, since the accessory hardware can often generate higher noise levels than the compressor if not selected and installed correctly. Guidelines for valve sizing, proper lagging of piping and valves for noise reduction, drain line noise attenuation, inlet silencer selection, discharge silencer selection and silencer installation will also be explored. The refining, petrochemical, oil and gas, automotive, steel, electronic and industrial applications utilize centrifugal air compressors to provide utility air to support manufacturing their processes. They are often purchased to meet a specified noise level based on customer site requirements. Compressors that meet the noise requirement without using a complete sound enclosure are preferred. This is due to both the high cost associated with sound enclosures and because sound enclosures make access to the compressor difficult for maintenance. Figure 1 shows a typical centrifugal air compressor package for a refinery application