Basma Yaghi

Heavy Crude Oil Viscosity Reduction for Pipeline Transportation

The approaches used for reducing the viscosity of a heavy crude include heating, blending with a light crude and with kerosene, and forming oil-in-water emulsions. Heating had a dramatic effect on the heavy crude viscosity, but it failed to achieve a practical level; consequently, blending the heavy crude with either light crude or kerosene was attempted and further reduction was achieved, but substantial amounts of these expensive diluents are required. Alternatively, emulsion formation was carried out, and it was established that a practical level of reduction is achievable at 70-75% oil content, in the high shear rate range, and at 30-50°C. The effect of temperature on the viscosity of the crude oil mixtures and emulsions can be fitted on the American Society for Testing and Materials (ASTM) double-log model with an average deviation of 7.2-9.4%.

Levels of heavy metals in outdoor and indoor dusts in Muscat, Oman

The concentrations of lead, copper, nickel, zinc and chromium in outdoor and indoor dusts collected from different sites in Muscat, Oman, were determined by flame atomic absorption. Results showed a wide range of concentrations, the means in the outdoor dust being, 65 ± 50, 124 ± 316, 47 ± 45, 930 ± 666 and 64 ± 26 mg kg− 1 for lead, zinc, copper, nickel and chromium, respectively. The 2001 Omani phasing out of leaded fuel resulted in low levels of lead in outdoor dust compared to those reported in the literature. Outstanding was the high nickel concentration in outdoor dust when compared to that in the literature, the reason being natural soil pollution due to the local geology of the northern parts of Oman. The concentrations of chromium, copper and zinc are lower than or comparable to these in other cities around the world. The results also showed that the industrial activities in Muscat do not contribute significantly to metal pollution in street dusts. On the other hand, the mean concentrations of lead, zinc, copper, nickel and chromium in indoor dust were 108 ± 65, 753 ± 1162, 108 ± 91, 130 ± 125 and 34 ± 14 mg kg− 1, respectively. In general, zinc and nickel levels are higher than those reported in the literature while lead, copper and chromium levels are lower or comparable. When outdoor and indoor dusts were correlated, the ratios between indoor–outdoor mean concentrations revealed that lead, zinc, and copper were generated internally, while nickel and chromium were from external sources.

Rheology of oil-in-water emulsions containing fine particles

Abstract The effect of fine solids on the viscosity of oil-in-water emulsions was investigated. The emulsion–solid mixtures were prepared from oils having viscosities of 20, 60, and 220 mPa s with the addition of 0–2% particles. The relative viscosities of the emulsion–solid mixtures were functions of the oil and solids, and the shear rate. General equations commonly used in the literature could not predict the viscosity of the emulsion–solid mixtures. The relative viscosities at high shear rates (≥450 s −1 ) could be correlated by η r =exp[( b ×ln( ϕ o )+ c )× ϕ s ], where b equals 85 and c ranges from 195 to 208.

Assessment of lead, zinc, copper, nickel and chromium in total suspended particulate matter from the workplace in Al-Rusayl Industrial Estate, Oman

Total suspended particulates (TSP) were collected with a high volume sampler from the indoor work environment of 23 industries in Al-Rusayl Industrial Estate in Muscat, Oman. The values measured ranged from 39 microg m(-3) to 1033 microg m(-3). TSP in the ambient air of the area was found to have an average value of 1802 microg m(-3). TSP were analyzed for Pb, Cu, Ni, Zn and Cr. Compared to other metals, Pb emission was high with values ranging from 3 to 15 109 ng m(-3) with the mean value being 1 293 ng m(-3); Cu concentration varied from 3 to 2600 ng m(-3) with a mean value of 131 ng m(-3); Ni concentration ranged from 6 to 46 ng m(-3) with a mean value of 17 ng m(-3); Cr concentration ranged from 1 to 133 ng m(-3) with a mean value of 23 ng m(-3) while that of Zn varied from 0.01 to 1 978 ng m(-3) with the mean value being 464 ng m(-3). The concentrations of Pb, Ni, Cu, Cr, and Zn in the ambient air were also measured and found to have the following values: 122, 18, 16, 5 and 0.01 ng m(-3), respectively. These values indicate that the industries in the area do not contribute significantly to heavy metal air pollution.

A Comparative Study of Lost Circulation Materials

In this article, the objective is to identify an alternative lost circulation material (LCM) to combat typical operational problems associated with drilling mud losses. These problems cost the local oil company significant downtime. In the oil industry, and, of course, to the local oil company, most of the commercial lost circulation materials have been tested with different levels of success. The trend now is to rethink different ways to better tackle the mud losses intricate problem and reduce drilling costs. The objective is to investigate possible gelling and bridging agents that are currently used by other industries. To start, an extensive literature search for possible LCM candidates from industries like construction, refrigeration, pleasure-boat manufacturing and others is embarked on. The next challenge would be to envisage a thorough chemical screening and testing program to come up with an LCM that could be effective if pumped through thief zones. The effectiveness yardstick could then be measured by: (1) solving the problems of placement, (2) temperature, (3) pressure, etc.

VISCOSITY OF WATER-OIL EMULSIONS WITH ADDED NANO-SIZE PARTICLES

The viscosity of emulsion and suspensions in the presence of two types of nano-size particles that, have different affinity for oil, have been investigated. It has been found out that both oil-solid suspensions and oil-water-solid mixtures behave as pseudoplastic fluids at all studied solid concentrations. The viscosity of emulsion-solid mixtures does not seem to get affected by water concentration, yet it is a function of solid concentration. The ability of solids to act as emulsifying agents has also been investigated. It has been established that neither of the two types of solids used is capable of stabilizing water-in-oil or oil-in-water emulsions in the absence of surfactants. At low concentrations of solids and in the presence of an oil-soluble surfactant, both oil-wet and water-wet solids, however, are capable of stabilizing water-in-oil emulsions. In the presence of water-soluble surfactant, only water-wet solids are capable of stabilizing oil-in-water emulsions.

Use of Plants to Monitor Contamination of Air by SO2 in and around Refinery

Abstract The generation of SO2 from a refinery may affect the surrounding environment. Moreover, SO2 and its by-products are phytotoxic as berg. This study aims to investigate plant responses to SO2. The work has been designed with emphasis on using the plants directly in monitoring the contamination of the atmospheric air by SO2. An assessment was made of the impacts of long-term SO2 emissions from an oil refinery on plants located in nearby areas that are likely to be exposed to emission fallout. Three different plant species (Prosopis cineraria, Azadirachta indica, and Phoenix dactilifera) common to the environment of the Arabian Gulf were selected at different distances and directions from the refinery. The analysis of the sulphate contents of these plants were used as bioindicators for monitoring SO2 concentration levels in and around the refinery. The results of this study showed that the three different plant species responsed differently to SO2 in terms of their sulphate contents. Generally, all three species were found to be sensitive to SO2 exposure. Furthermore, the concentration of sulphate was found to be much higher closer to the refinery. On the basis of this study, it can be stated that even though SO2 levels were lower than the permissible limit values, the sulphate contents accumulated in the plants were likely to cause plant injury especially in the vicinity of the source. This suggests that the present environmental guidelines for SO2 may not protect sensitive plant species.

Use of Tank Bottom Sludge to Construct and Upgrade Unpaved Roads

Tank bottoms are the liquids and residue, such as heavy hydrocarbons, solids, sands, and emulsions, that collect at the bottom of the treating vessel or that remain at the bottom of storage tanks after a period of service. Sludge composition is 50% to 65% crude oil, 20% to 35% water, and 5% to 20% solids. Disposal of tank sludge is a significant item of tank maintenance costs. Results are presented on the use of tank bottoms as a binder to construct and upgrade unpaved roads. Various sludge samples were initially characterized for chemical and physical composition, then three mixtures were prepared by using blends of aggregates and tank bottoms. No bitumen was used in the mixes. The mixtures include hot mix (aggregate and sludge were both heated), heated sludge and cold aggregate mix, and cold mix (no heat was applied). The Marshall mix design (ASTM D1559) was followed in the preparation and testing of the specimens. Results indicate that tank bottoms act as a binder to the aggregate and can provide significant strength. Heating both the sludge and the aggregate resulted in the highest stability value of 11.9 kN. An optimum sludge content of 6.5% by total weight of the mixture satisfied the requirements for low (3.3 kN) or medium (5.3 kN) trafficked surfaces or base layers according to Asphalt Institute specifications. Other mix properties, such as flow, air voids, voids in mineral aggregate, and voids filled with asphalt, were acceptable.

Effect of Temperature and Solids on the Rheology of Water-in-Oil Emulsions

Abstract This article reports on an experimental study on the effect of temperature on the viscosity behavior of water-in-oil emulsions with added solids. The experimental conditions consisted of combinations of values of temperature (T) and solids volume fraction (φ s ). The temperature had the values of 10, 20, 30, 40, 50, and 70°C; whilst the solids volume fraction had values between 0 and 0.025. All the treatments had been chosen such that each value of φ s was used once in conjunction with each value of T. In order to obtain an estimate of the experimental error in the experiment, it was necessary to replicate the entire set of experiments a total of three times. Statistical analysis of the experimental data pointed to the existence of an interaction of solids and temperature and to the relative viscosity being a function of these two factors. A model based on the data has been developed to evaluate the relative viscosity as a function of T and φ s for shear rates above 270 s−1.

Production of cosmetics and fishmeal from mercury‐contaminated fish‐extracts prior to waste disposal on municipal dump sites

The potential effect of deploying mercury‐contaminated fish‐extracts for the manufacture of cosmetics and fishmeal, and discarding the ensuing waste material on municipal dumps was investigated. Our study showed that some levels in fishmeal were elevated and could exceed 600 µg/kg; while the concentrations in fish‐oil (for cosmetics production) and fish‐water (dumped) were appreciable and reached levels of 16 and 12 µg/kg, respectively. Samples, collected from a central production plant were analysed directly by the cold‐vapour atomic absorption method. The method was validated by the use of standard addition, and acceptable relative standard deviations, well within ±5% were attained. Possible safety and remedial measures are discussed