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The material presented in this thesis falls into two main sections: 1. The determination of barium, strontium and calcium in oil-well waters (i) Determination of barium It is revealed that the addition of magnesium (5 g l-1) to samples for the determination of barium by d.c. plasma atomic emission spectrometry enhances the sensitivity of the analysis and dramatically reduces interference from calcium and strontium at both atomic and ionic emission wavelengths. (ii) Determination of strontium The determination of strontium in waters, was also subject to the interference of the concomitant elements like calcium, barium and magnesium. However, the addition of 3 g l-1 sodium with or without 5 g l-1 of magnesium eliminated all the interferences in the d.c. plasma and in the dinitrogen oxide-acetylene flame. (iii) Determination of calcium The determination of calcium in oil-well waters encountered some interference arising from the presence of sulfate. However, the effects of phosphate and sodium were also investigated in both air-acetylene and dinitrogen oxide-acetylene flames and in the direct current plasma. It was shown that the interference was reduced in the cool flame when 2 g l-1 of lanthanum was added. The absorbance of calcium was depressed by the presence of 2 g l-1 of sodium. The interferences from both sulfate and phosphate were eliminated when the hot flame or the d.c. plasma were used. 2. Slurry nebulization for soil, sediment and fertilizer samples A slurry atomisation direct current plasma (DCP) emission and flame atomic absorption and emission (FAAS and FAES) for the determination of alkaline earth elements and also of other minor and major elements in soils, marine sediments and fertilizer is reported. The results obtained by slurry nebulization, with lithium added as ionisation buffer, were compared with results obtained following fusion with LiBO2 at 950o for 10 minutes and dissolution of the residues in 4&'37 HNO3.

Analytical procedures have been developed for the quantitative analysis of phenols in crude oils and sedimentary rock pyrolysates and extracts. The procedures involve isolation of the phenolic components of the sedimentary organic matter by extraction with alkaline aqueous methanol, followed by the removal of carboxylic acids using a back extraction step. Co-extracted non-polar components are removed from the alkaline extract by liquid chromatography or by extracting it with hexane. The phenol isolates thus obtained were analysed by capillary GC, GC-MS and GC-FTIR. Recoveries of 70-95% were measured for C(subscript)0-C(subscript)3 alkylphenol compounds using these procedures.Crude oil samples (45) representing a range of locations, ages, depositional environments, maturities, source types, and biodegradation levels have been analysed for their phenol contents. A range of C(subscript)0-C(subscript)5 alkylphenols (approximately 40) were identified in crude oils using co-chromatography on up to three different stationary phases and by comparison of their retention times, mass spectral and infrared spectral properties with reference compounds. Isopropylmethylphenols (six) and sec-butylmethylphenols (nine) were synthesised for use in the identification of these compounds. A range of C(subscript)0-C(subscript)4 alkylphenols (24) were quantified using a dimethyl siloxane column (BP 1 or DB 1) and found to occur at concentrations ranging from 190x10(subscript)3 ng/g down to the limit of detection of 10 ng/g (ppb).The crude oil samples were classified into six groups based on their C(subscript)0-C(subscript)5 alkylphenol compositions. Group 1 crude oils have at least one isomer class in which the relative proportions of the alkylphenol isomers reflect their relative thermodynamic stabilities. The vast majority of samples, however, do not contain relative proportions of ++ / phenols which reflect their stabilities, and these differences have been used to group the remaining crude oils. Group 2 crude oils contain predominantly alkylphenols derived from natural product precursors. This group has been further subdivided into Group 2A in which samples have isopropylmethylphenol distributions dominated by carvacrol and thymol; and Group 2B which is comprised of crude oils that contain high relative abundances of methylphenols which can be derived from tocopherols. Group 3 crude oils have C(subscript)2-C(subscript)5 alkylphenol compositions dominated by ortho and para substituted phenols which are proposed to be formed from geosynthetic processes. Group 4 crude oils contain alkylphenol compositions in which the relative abundances of meta substituted compounds in six isomer classes are much greater than those expected from chemical equilibration. Group 5 comprises of samples which are biodegraded and as a consequence contain alkylphenols below the limit of detection. Group 6 crude oils contain very low concentrations of alkylphenols and comprises samples which are derived from source rocks that pre-date the widespread occurrence of land plants or contain negligible land plant input.Some alkylphenols in crude oil are structurally related to natural product precursors and therefore appear to be biomarkers. The monoterpenoid natural products carvacrol and thymol, or its rearrangement product 3-isopropyl-5-methylphenol, which occur in high relative abundances in Group 2A samples are such compounds. Because carvacrol and thymol occur widely in extant conifers and angiosperms, their presence in crude oils derived from source rocks deposited when these plant types were widespread suggests they also originate from these plants. A range of trimethylphenols and tetramethylphenols which occur in high relative abundances in Group 2B samples, are also ++ / reaction products obtained from heating alpha-tocopherol with aluminium smectite. This, together with the reported widespread occurrence of tocopherols in plant photosynthetic tissue and in sedimentary rocks, leads to the conclusion that tocopherols are likely precursors to these petroleum methylphenols.The lignin components of terrestrial plants also appear to be important precursors to petroleum alkylphenols. Strong evidence for this is provided by the observation that crude oils derived from source rocks which contain negligible higher plant input contain very low concentrations of kylphenols (Group 6). In order to determine the likelihood of lignins as precursors of petroleum alkylphenols, the phenol contents of coals of lignitic through to bituminous rank were examined. The unbound phenolic components of the lignite samples were analysed by isolating the phenols from their dichloromethane extracts, and the bound phenolic components were analysed by pyrolysis GC-MS. At lignitic rank the unbound methoxyphenols allowed taxonomical classification of the samples and the bound hydroxyphenols bore structural similarities to lignin moieties. The bound C(subscript)0-C(subscript)4 alkylphenol components of lignitic, subbituminous and bituminous coals in a sedimentary sequence were quantitatively analysed by isolating the phenols from their hydrous pyrolysates. In the coals of subbituminous and bituminous rank, the bound alkylphenol components could not easily be related to lignin precursors because molecular transformations of lignins are very severe at these ranks. The increases in the individual concentrations and relative proportions of alkylphenols with methyl and/or isopropyl substituent(s) in the ortho and para positions in the subbituminous coal pyrolysate were attributed to electrophilic methylation and isopropylation reactions occurring to lignin structures in ++ / coals during coalification. The dominance of ortho and para substituted methylphenols in coaly Group 3A crude oils which were also observed in the hydrous pyrolysates of coals suggests that the altered lignin structures in coals may be precursors of some of these petroleum methylphenols.Methylation, isopropylation and sec-butylation, are proposed as geosynthetic processes to account for the alkylphenol compositions of crude oils with phenol distributions dominated by ortho and para alkyl-substituted compounds (Group 3). Many crude oils show high relative abundances of ortho and para substituted C(subscript)1-C(subscript)5 alkylphenol isomers and some were also enriched in C(subscript)3-C(subscript)5 alkylphenols compared to kerogen pyrolysates. Because the alkylphenol products obtained from the laboratory alkylation of cresols have distributions which closely resemble those in these crude oils, it is proposed that similar alkylation processes occur in source rocks. Alkylation ratios reflecting the degree of methylation, isopropylation and sec-butylation, which were based on the relative abundance of the dominant alkylation products compared to their likely precursor ortho cresol, indicate that high levels of methylation occurred in crude oils over a wide range of maturities. In contrast, high levels of isopropylation and sec-butylation were observed only in mature samples. Selective dissolution of phenol isomers in crude oils by water contact was discounted as an explanation for the observed phenol distributions based on the relative distribution coefficients of phenols between isooctane and water.The alkylphenol compositions of the remaining crude oils appear to be produced from alteration processes occurring in the subsurface; these include oxidation and biodegradation processes. Oxidation of alkylphenols is proposed to account for the alkylphenol compositions of ++ / Group 4 crude oils. Because ortho and para substituted alkylphenols are more susceptible to oxidation than their meta substituted counterparts, the selective removal of these compounds via an oxidation process is suggested as an explanation for the high relative abundances of meta substituted isomers observed in these crude oils. A natural product origin for these compounds appears unlikely due to the lack of known natural products which could give rise to meta substituted alkylphenols with isopropyl substituents, and the diverse range of organisms required to give rise to the meta substituted phenols with n-alkyl substituents observed in Group 4 samples.Crude oils from two Australian basins which have undergone various levels of biodegradation were analysed to assess biodegradation effects on petroleum alkylphenol compositions. Alkylphenols could not be detected in the moderately to severely biodegraded crude oils (Group 5) whereas related non-biodegraded samples contained relatively higher levels of alkylphenols. The very low levels of phenols in the biodegraded samples (< 10 ppb) suggests that phenols are depleted via processes that occur during biodegradation. Because water washing often co-occurs with biodegradation, the very low levels of alkylphenols in these samples may also be due in part to the removal of these polar components via water dissolution.

An understanding of the processes involved in oil spills, and how they interact to alter the composition and behavior of the oil with respect to time is essential to determine an effective oil spill response. The review of past research has shown more focus on the laboratory methods and computerized modeling schemes to estimate the formation and breaking of emulsions after an oil spill. However, relatively less effort has gone into the study of emulsions corresponding to actual field conditions. This research aims to simulate an oil spill at sea by developing a new technique to make water in oil emulsions, without disturbing the marine wildlife. Further, this research also attempts to analyze the viscosities of water in oil emulsions and determine appropriate emulsion breakers for different crude oil emulsions. The overall test design for the study includes a test apparatus for spreading and evaporation, three different crude oils, a mixing chamber to form the emulsion, and emulsion breakers. Experiments in this research attempt to gain a better understanding of the processes that occur after oil spills at sea. In particular, the rate of evaporation of different crude oils and the formation of crude oil emulsions on the sea surface have been investigated. It was observed that different crude oils behave differently when subjected to the same weathering procedure. Results indicate that the behavior of the crude oil on the sea surface, subjected to spreading, evaporation, and emulsification, can be predicted by using the new technique developed in this research. This technique can also assist the development of effective recovery equipments and materials.

An understanding of the processes involved in oil spills, and how they interact to alter the composition and behavior of the oil with respect to time is essential to determine an effective oil spill response. The review of past research has shown more focus on the laboratory methods and computerized modeling schemes to estimate the formation and breaking of emulsions after an oil spill. However, relatively less effort has gone into the study of emulsions corresponding to actual field conditions. This research aims to simulate an oil spill at sea by developing a new technique to make water in oil emulsions, without disturbing the marine wildlife. Further, this research also attempts to analyze the viscosities of water in oil emulsions and determine appropriate emulsion breakers for different crude oil emulsions. The overall test design for the study includes a test apparatus for spreading and evaporation, three different crude oils, a mixing chamber to form the emulsion, and emulsion breakers. Experiments in this research attempt to gain a better understanding of the processes that occur after oil spills at sea. In particular, the rate of evaporation of different crude oils and the formation of crude oil emulsions on the sea surface have been investigated. It was observed that different crude oils behave differently when subjected to the same weathering procedure. Results indicate that the behavior of the crude oil on the sea surface, subjected to spreading, evaporation, and emulsification, can be predicted by using the new technique developed in this research. This technique can also assist the development of effective recovery equipments and materials.

No description available.

No description available.

This study evaluated the nutritional and antioxidant properties of Sesamum indicum, Cucumeropsis edulis and Cucurbita pepo seeds by determining proximate composition and mineral composition by atomic absorption spectroscopy and antioxidant assays. C. pepo had the highest protein (28.31%), S. indicum had the highest fat (52.53%) and C. edulis had the highest fiber content (6.23%), and highest total antioxidant capacity (199.75 mg AAE g−1 dry weight of ethanol extract). Magnesium, potassium, iron, calcium, sodium and zinc were the most abundant mineral elements present in these seeds.

No description available.

Heat-integrated crude oil distillation systems – the atmospheric and vacuum distillation towers and associated heat recovery system – are energy and capital intensive. The structures of the distillation columns are very complex and the distillation columns interact strongly with the preheat train. There are many degrees of freedom in this system, most of which are interlinked with each other and cannot be considered separately. A systematic design approach is necessary to exploit these design issues for increasing the efficiency with which energy and capital are employed in the overall system. This thesis develops an optimisation-based methodology for the simultaneous design of crude oil distillation systems. Both new design and retrofit scenarios are considered. This design approach considers some significant design issues and generates design solutions that are realisable and industrially practicable. Robust and more accurate models have been developed to represent the distillation columns and heat exchanger networks (HENs) within an optimisation framework, compared with previous work. Facilitated by the decomposition approach (Liebmann, 1996), simplified models (Suphanit, 1999; Gadalla et al., 2003a; Rastogi, 2006), based on the Fenske-Underwood-Gilliland method, were developed previously to model the atmospheric distillation unit and the vacuum unit. This work extends and modifies these simplified models to account more accurately for the effect of pump-around location on the separation performance in atmospheric units. Moreover, the simplified model has been extended to consider an atmospheric distillation column with a pump-around located above the top side-stripper. This work also proposes a new methodology to incorporate product specifications following refining conventional in the simplified models. The proposed approach enables systematic identification of key components and associated recoveries to match specified boiling temperature profiles, as these are normally used as indicators of separation performance in the refining industry. The new simplified models are validated by comparison with rigorous simulation results of atmospheric distillation columns. Multi-segmented stream data are implemented in the design and analysis of heat exchanger networks, in which the thermal properties of streams are temperature dependent and cannot be assumed constant. Two existing promising HEN design approaches, the simulated annealing optimisation-based approach (Rodriguez, 2005)and the network pinch approach (Asante and Zhu, 1996), are modified and extended to apply to the HEN design with multi-segmented stream data. In the modified network pinch approach, the bottleneck of an existing HEN configuration is better overcome by varying stream split fractions and heat exchanger loads at the same time, rather than simply redistributing heat loads. The modified network pinch approach also combines structural modifications and cost optimisation in a single step to avoid missing cost-effective design solutions. An optimisation framework, applying a stochastic optimisation method – multiple simulated annealing runs – is developed to generate grassroots and retrofit designs of the heat-integrated crude oil distillation systems. The heat integration of the system is accounted for more accurately than previously by using multi-segmented stream data. Operating conditions and pump-around locations of distillation columns are optimised, together with structural options and continuous variables of heat exchanger networks as appropriate, in a single optimisation framework. The new degrees of freedom considered in this work include key components and associated recoveries (used in simplified models of distillation columns to express the separation of products) and operating pressures of distillation columns. The optimisation of key components and recoveries allow the systematic exploitation of product distributions and product slate in order to maximise net profit. Including operating pressures in the optimisation facilitates creation of heat recovery opportunities in configuration studies. Product specification constraints are imposed in the optimisation so that product quality is not compromised during design. A novel distillation configuration, with a liquid side-draw prefractionator column upstream of an atmospheric distillation column, is proposed in this work. The case study shows a very promising performance with respect to energy efficiency. Case studies illustrate the beneficial application of the proposed approach in both grassroots and retrofit design of crude oil distillation systems, with respect to energy demand and net profit improvement. Comparisons are made between different configurations, and results are given as proof of principle.