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Yes / Waxy crude oils are pumped hot but upon power cut, pumping stops, the oil cools leading below the wax appearance temperature to precipitation of the wax and the formation of a gel throughout the pipe. In such a situation, what is the minimum pressure required to restart flow, not to merely deform the gel or break it? This paper provides a solution to this problem using microscopic observations under controlled cooling conditions and rheological data conducted in constant stress mode under controlled temperature and cooling conditions and restart experiments in laboratory pipelines replicating the rheometric conditions and deviations from them to inform large diameter operation in the field. Three important findings derive from the experimental data collected: (i) A fragmentation stress , rather than the static stress that precedes it, is found to be the more accurate predictor of flow re-start pressures; (ii) Waxy crude oils gels exhibit true yield stress and yielding process but also show flow on application of the slightest stress below yielding; (iii) This flow, in the elastic region, is jagged rather than continuous suggesting a consolidation process of the crystals and their agglomerates forming the gel. In the broader context of the existence of a yield stress, the data presented here show that there is such a thing as a yield stress and the concepts of a yield stress and that everything flows are not mutually exclusive.

No / In this paper, hydrodesulfurization (HDS) of crude oil in the three-phase slurry reactor over cobalt – molybdenum catalyst (CoMo / ɣ- AL2O3) is studied. Effects of space velocity and length of reactor on the conversion rate and catalyst effectiveness for HDS process have been investigated. Kinetics of the reaction rate for this process is primarily and Arrhenius equation for the rate constant is used. The results show that the effectiveness factor for catalyst along the length of reactor is decreased about 83%. By increasing liquid velocity from 4 to 10 1/s, the conversion of sulfur components is decreased about 22% at the temperature of 523 K. At the same temperature, by increasing liquid velocity from 36 to 84 1/s conversion is reduced to 25%. The results of the variation of the dimensionless reaction rate against conversion show that with increasing conversion, the reaction rate decreases and the reaction is stopped when the conversion is 100%.

The objective of this thesis was to understand the factors that affect the selection of remedial treatments for the complex staining of masonry materials on cultural resources located in environmentally sensitive sites such as Fort Livingston, Louisiana, on the Gulf Coast of the United States and other locations impacted by pollutants including crude oil. After the Deepwater Horizon oil spill in April 2010, the brick-and-tabby Fort was stained by crude oil. The EPA recommends SWA for removal of oil from solid surfaces such as masonry; however, limited research has been conducted into SWA effective for removal of crude oil from masonry, particularly in remote and environmentally sensitive locations. Research was conducted collaboratively at NCPTT and UT-Austin to identify a series of suitable SWA and to develop methods for evaluating SWA effectiveness in the laboratory. Products were selected for laboratory evaluation that do not require long dwell times, are easy to transport to the site, can be applied with portable equipment, produce effluent that can be collected for off-site disposal, and are listed on the EPA-published NCP Product Schedule. Two sets of 36 brick samples each were soiled with crude oil from the Fort. One set of samples was artificially weathered and one set was unweathered prior to being cleaned with selected six SWA. Laboratory evaluation shows that the primary factor affecting cleaner selection for remediation of brick masonry stained by light crude oil is the extent of weathering of oil on the masonry. For light crude oil, such as that spilled in the Gulf, organic solvent-based cleaners may be most effective if cleaning is possible soon after the staining occurs. Aqueous surfactant cleaners are most effective for removing weathered light crude oil from masonry. The following SWA listed in order of performance are recommended for field trials at Fort Livingston: 1. Cytosol; 2. SC-1000; 3. De-Solv-It APC; 4. De-Solv-It Industrial followed by De-Solv-It APC; 5. De-Solv-It Industrial followed by SC-1000. / text

Crude oil is of economic importance to any nation. However its poor management and disposal method has resulted in oil spillage and ground contamination. Most emphasis on crude oil contamination on the environment has been on surface and ground water pollution, as well as plants and animals with little or no attention paid to the engineering properties of the contaminated soil. This research is thus aimed at investigating the effect of light crude oil contamination on the geotechnical properties of kaolinite clay soil. This research is a laboratory based experiment in which the contaminated soil was prepared by adding different percentages of light crude oil (2%, 5%, 8%, 10%, 15% and 20%) measured by weight of the dry soil sample and mixed until a uniform mixture was obtained. The British Standard Test Methods for Civil Engineering purposes BS 1377: 1990 (EUROCODE 7: EN 1997: 2-5) was adopted with few modifications. The calculations were based on the fact that the pore space in the contaminated soil is occupied by water and crude oil so water content was calculated from the fluid content and the rate of evaporation of crude oil during oven drying was also considered. The classification results showed that crude oil contamination caused an increase in linear shrinkage, liquid limit, plastic limit and plasticity index between 0% to 20% contaminations. The compaction result showed that there was an increase in maximum dry density while the optimum moisture content decreased between 0% and 15% of crude oil contamination. The result showed that the soil could not compact at 20% contamination and above. Also, the coefficient of permeability increased with increase in the percentage of crude oil contamination while the coefficient of consolidation value (Cv) increases with increase in the percentage of contamination. There was a decrease in the cohesion value and the frictional angle due to the introduction of the crude oil into the soil. Although crude oil altered the geotechnical properties of the kaolinite clay soil and reduced its strength, the soil can still be used for geotechnical purposed after remediation.

The recovery characteristics of Bolu-Himmetoglu, Bolu-Hatildag, K&uuml / tahya- Seyit&ouml / mer, and Nigde-Ulukisla oil shale samples and Bati Raman, &Ccedil / amurlu, and Garzan crude oil samples were tested experimentally using retort and microwave heating techniques. Many parameters like heating time, porosity, water saturation were studied. To enhance the efficiency of the processes three different iron powders (i.e. / Fe, Fe2O3, and FeCl3) were added to the samples and the doses of the iron powders were optimized. While crude oil viscosities were measured to explain the fluid rheologies, since it is impossible to measure the shale oil viscosity at the laboratory conditions due to its very high viscosity, shale oil viscosities were obtained numerically by using the electrical heating option of a reservoir simulator (CMG, STARS 2007) by matching between the laboratory and numerical oil production and temperature distribution results. Then the field scale simulations for retorting of oil shale and crude oil fields were conducted. Since the microwave heating cannot be simulated by CMG, STARS, microwave heating was modeled analytically. In order to explain the feasibility of heating processes, an economic evaluation was carried out. The experimental, numerical, and analytical results show that field scale oil recovery from oil shales and heavy crude oils by electrical and electromagnetic heating could be economically viable. While microwave heating is advantageous from an operational point of view, retorting is advantageous if the technically feasibility of the study is considered.

Oil is a very complex chemical system, as for instance, the paraffinic type which was considered as a fluid to be evaluated in this scientific paper, trough the static interfacial tension with the surfaces of the API 5L grade B conduction pipe and the EPOXY and EPOXY M resins. The paraffinic oil produced in the 7-PIR-244D-AL well, which is located in the producing field of Pilar in the state of Alagoas, presents special characteristics concerning its flow which are different from the other oils in the Sedimentary Basin of Sergipe and Alagoas. The resin used in the experiments were the EPOXY, commercially know as DGEBA, as well as EPOXY M, which was produced from the DGEBA with the addition of a substance whose objective is to reduce the deposit of organic and/or inorganic molecules in its surfaces along the oil flow. The evaluation of the static interfacial tension between this type of paraffinic oil and the surfaces of the EPOXY (37,2 mN/m), EPOXY M (14,8 mN/m) resins and the steel pipe (4.790,2 mN/m) has produced results, the performance of this fluid compared with the EPOXY M resin was better than when compared with the EPOXY and, as a consequence, better than when compared with the metallic material of the pipe. As a result of the data got through the experiments with these materials, there was a conclusion about the possibility of practical use of the EPOXY M resin as a coating in the internal surface of the pipes that carry oil with a considerable quantity of paraffin in its composition, aiming at a better performance relating to the flow of this fluid. / O petróleo é um sistema químico bastante complexo, como por exemplo, o do tipo parafínico, o qual foi considerado como o fluido para ser avaliado nesse trabalho científico, através da tensão interfacial estática com as superfícies do tubo de condução metálico API 5L grau B e das resinas EPÓXI e EPÓXI M. O óleo parafínico produzido no poço 7-PIR-244D-AL, o qual está localizado no campo produtor de Pilar no estado de Alagoas, apresenta particularidades com relação ao escoamento, diferentes dos outros petróleos na Bacia Sedimentar de Sergipe e Alagoas. As resinas utilizadas nos experimentos foram a EPÓXI comercialmente denominada DGEBA, como também a EPÓXI M que foi produzida a partir da DEGEBA com a adição de uma substância cuja finalidade é reduzir o depósito de moléculas orgânicas e/ou inorgânicas nas suas superfícies durante o escoamento do petróleo. A avaliação da tensão interfacial estática entre este tipo de petróleo parafínico e as superfícies das resinas EPÓXI (37,2 mN/m) e EPÓXI M (14,8 mN/m) como também do tubo de aço (4.790,2 mN/m), gerou resultados; onde a performance desse fluido com relação a resina EPÓXI M foi melhor quando comparada com a EPÓXI, e conseqüentemente em relação ao material metálico do tubo. Como conseqüência dos dados obtidos através dos experimentos realizados entre estes materiais, concluiu-se a possibilidade de uso prático sobre a utilização da resina EPÓXI M como revestimento junto à superfície interna de tubulações que possuam petróleo com considerável quantidade de parafina em sua composição, objetivando um melhor desempenho quanto ao escoamento desse fluido.

The efficacy of using zeolitic materials for the removal of nickel (II) and vanadium (IV) ions from solution has been evaluated in order to provide a method for the removal of the metal ions during hydroprocessing of crude oil. Batches of sodium based zeolites with a variety of pore sizes and Si/Al ratios were prepared using standard methods (high causticity solutions and templating agent). Characterisation of the products was carried out using powder X-ray diffraction, infrared spectroscopy, Raman spectroscopy and thermogravimetric analysis to confirm the presence of single zeolitic phases (zeolite A, zeolite X, zeolite Y, sodalite Na8 [AlSiO4]6Cl2 and hydrosodalite Na6 [AlSiO4]6. 6H2O). In a batch exchange process, divalent nickel and tetravalent vanadium ion solutions of concentration range 0.01M - 0.1M were placed in contact with the zeolite samples at 110°C for a period of 24h. Nickel (II) exchange was found to occur for all the zeolites at concentrations considered. Zeolite X was found to be most efficient at removing nickel from the solutions while zeolite Y was least efficient. Characterisation of zeolite X after ion exchange using powder X-ray diffraction and scanning electron microscopy showed that the structure of the zeolite had been maintained. Simplistic modelling of powder X-ray diffraction data have shown that the nickel ions are preferentially substituted on one of the four sodium sites. Vanadium (IV) exchange was also found to occur for all the zeolites at the concentrations considered. Zeolite A was found to be most efficient for the vanadium uptake. Characterisation with PXRD, FTIR and SEM-EDS however, shows that in addition to exchange at the zeolite s normal cation exchange sites, a significant amount of framework silicon species were also exchanged by the vanadium ions thus having a destructive effect on the zeolite framework leading to structural collapse. Ion exchange of the sodium-based zeolites with potassium and lithium showed that the uptake of nickel and vanadium of the zeolites significantly increased compared to the as- synthesised zeolites. Zeolite Y was surface-modified with the APTES ligand and showed a similar trend to that observed for alkali metal-zeolites; showing significantly greater nickel uptake at lower concentrations. Nickel-tetraphenylporphrin was synthesised as a mimic for the nickel-asphaltenes found in crude oil and an α-hydrogen donor solvent used to remove the nickel in the presence of zeolite ion exchangers. A similar trend was observed to that seen in aqueous solution, implying the process would be transferrable to a live medium. Analysis to determine the metal ions present in ashed Nigerian crude samples before and after solvent and/or complexing agent extraction was carried out using inductively coupled plasma mass spectroscopy (ICPMS) and energy fluorescence analysis by X-rays (XRF). The process showed varying amounts of nickel was extracted by the different media along with iron. For nickel, the extent of extraction in the order of increasing % extraction is H2O<H3PO4<EDTA<IPA. For iron the order of increasing % extraction was H2O=EDTA<H3PO4<CH3OH while zinc extraction was in the order H2O<H3PO4 <CH3OH=EDTA.