In crude oil production from brown fields or heavy oil, there is production of water in oil emulsions which can either be controlled or avoided. This emulsion resulted in an increase in viscosity which can seriously affect the production of oil from sand phase up to flow line. Failure to separate the oil and water mixture efficiently and effectively could result in problems such as overloading of surface separation equipments, increased cost of pumping wet crude, and corrosion problems. Light hydrocarbon diluent was added in varied proportions to three emulsion samples collected from three different oil fields in Niger delta, Nigeria, to enhance the demulsification of crude oil emulsion. The viscosity, total petroleum hydrocarbon, and quality of water were evaluated. The viscosity of the three emulsions considered reduced by 38, 31, and 18%. It is deduced that the increase in diluent blended with emulsion leads to a corresponding decrease in the value of viscosity. This in turn enhanced the rate of demulsification of the samples. The basic sediment and water (BS&W) of the top dry oil reduces the trace value the three samples evaluated, and with optimum value of diluent, TPH values show that the water droplets are safe for disposal and for other field uses.

Proper slurry design is critical to the success of a cementing job. The best method to obtain a good slurry design with desired compressive strength is by laboratory experiments which involve experimenting different formulations and selecting the best composition for the specific cementing operation. This exercise is not only time consuming considering the amount of time required, but also expensive. Sixteen sets of experiments were conducted in the laboratory, and factorial design was used to design the experiments for the sensitivity analysis of four different factors impacting on the compressive strength of cement slurry. The responses from the 16 experimental runs were used to develop a model which can be used for optimization purposes. The model developed was simple, in agreement with the experimental data used and can be implemented using an ordinary simple calculator. Coefficients of main effects of X 1 , X 2 , X 3 , and

Modified Palm Kernel Shell Activated Carbon (PKSAC) using silver nanoparticle (Ag-NPs-PKSAC) was investigated on phenol uptake from aqueous solution. Effects of temperature (500–700 °C), time (90–120 min), and alkaline concentration (0.1–0.5 M) were studied on the yield and methylene blue numbers for the synthesis. Effects of initial concentration (100–200 mg/L), agitation (150–250 rpm), contact time (30–120 min), and adsorbent dosage (0.15–0.25 g) were studied in a batch experiment on percentage removal of phenol. The PKS, char, PKSAC and Ag-NPs-PKSAC were characterized using BET, FTIR, SEM, and proximate analyses. The synthesis of PKSAC was optimum at 608 °C, 0.5 M KOH, and carbonization holding time of 60 min. The optimum phenol uptake was 85.64, 90.29 and 91.70% for PKSAC, Ag-NPs-PKSAC, and commercial adsorbent, respectively. The adsorption mechanism of phenol followed the Langmuir isotherm and best described as physio-sorption with pseudo-second-order kinetics. Phenol exhibits high affinity (ΔS° = 0.0079 kJ/mol K) for Ag-NPs-PKSAC with favorable adsorption (ΔG° = -1.551 kJ/mol) at high temperature due to endothermic (ΔH° = 1.072 kJ/mol) nature of the system. The result obtained in this study compared favorably with the literature.

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A b s t r a c t. Oils available in mango, tangerine and African star seeds were extracted and characterized to determine their fuel worthiness for biofuel production. Furthermore, the fuel properties of the three oils were within the range observed for some common oil seeds like rapeseed, soybean and sunflower, which are widely sourced for the production of biodiesel on an industrial scale. The low iodine values of the oil extend their applications as non-drying oil for lubrication purposes, however, the fuel properties exhibited by the oils enlist them as potential oil seeds for the production of biofuel and further research on the improvement of their properties will make them suitable biofuel of high economic values.K e y w o r d s: fruits seed oil, biofuel, fuel properties INTRODUCTIONThe concern for fast depletion of petroleum oil and its environmental impact has shifted interest to alternative sources of fuels, particularly biofuels, which are renewable and environmental friendly (Demirbas, 2008). Thus, varieties of virgin, non-edible and waste vegetable oils have been sourced for the production of biofuels (Maniak et al., 2009). The choice of biofuel over diesel fuel includes its portability, availability, renewability, higher combustion efficiency, higher cetane number, higher biodegradability, high flash point, inherent lubricity, lower sulfur and aromatic contents (Knothe et al., 2005).Some of the widely sourced oil seeds for biofuels include rapeseed, soybean, palm, sunflower, jatropha, and castor seeds (Meher et al., 2006). However, some of the oils studied were characterized by higher viscosity, lower volatility, lower energy content, higher nitrogen oxide (NOx) emission rates, lower engine speed, reactivity of unsaturated hydrocarbon chains, higher cloud point and pour point (Enweremadu and Alamu, 2010). All these are contrary to the qualities found in the convectional diesel fuel, in the light of this, virgin oilseeds are studied for their potentials as viable source for biofuel production.African star apple (Chrysophyllum albidum) is a large berry fruit of plant family called Sapotaceae widely found in some West and Central African countries (Bada, 1997). The commercial value of the fruit is attracting interest particularly application of its seed oil as well as roots and leaves for medicinal purposes (Bada, 1997). Mango (Mangifera indica) fruit, on the other hand, is a drupe with a single seed, surrounded by yellowish or orange fibrous flesh, rich in vitamins. This tropical fruit tree thrives well in Asia and Africa continents and its shapes, sizes and colour depend on the variety (Nzikou, 2009). Tangerine fruit belongs to the family of Citrus genus and the sweet (Citrus sine sis) is the most widely grown of the citrus trees and the fruit is either eaten fresh or made into juice. The selected seeds contributed immensely to solid agricultural wastes found in most the towns where they are grown and consumed. This study examined the properties of oils obtained from African star apple, mango and tan...