Chemical & Petroleum Engineering-Conference Papers

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    Utilising Clean Coal Technologies for Meeting Nigeria’s Energy Needs
    (Proceedings of the Nigerian Society of Chemical Engineers, 2016) Denloye, A.O.; Akinola, A.A.
    Coal is expected to remain one of the dominant fuels in global electricity power generation as a result of its low cost, high reliability and high availability. In Nigeria, however, coal is yet to make a significant contribution to Nigeria’s energy needs because of the numerous challenges associated with coal electricity power generation. One of the challenges is that the use of coal to generate electric power produces toxic gases which are hazardous to human health and the environmental; it is also perceived as dirty to the environment. This paper focuses on the roles clean coal technologies can play in the sustainable exploitation of Nigeria’s coal reserves and how it can be effectively utilized to meet Nigeria’s energy needs. The Nigerian situation on electricity is reviewed and the Nigerian national policy on coal utilization is evaluated. Ways in which some aspects of the policy can be implemented are suggested. A number of clean coal technologies that can help overcome the challenges of electricity power generation were also reviewed. It is concluded that the core of the Nigerian National Policy on Coal should be the promotion of clean coal technology for electricity production. Clean coal technologies can reduce the hazardous gaseous emissions generated by the thermal decomposition of the coal. By developing clean coal technologies Nigeria will be able to use her considerable coal resources better and reduce the emissions of harmful substances associated with coal mining, thereby make asignificant contribution to Nigeria’s energy needs
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    Open Access
    Experimental Investigation of the Effects of Different Environmental Conditions on Pipelines Corrosion Rates
    (Society of Petroleum Engineers, 2019-08-03) Adeyanju, O.; Oyekunle, L.
    An estimate of about $18.5 million are expended by industries in Nigeria yearly on corrosion, the oil and gas industry takes more than 65% of this cost due to the peculiar nature of their facilities and operational conditions. In spite of the use of galvanized pipeline and application of the anti-corrosion coating of crude oil pipeline and other metallic structure in the oil and gas industry, corrosion failures are still daily occurrences. These corrosive failures have been attributed to the environmental conditions in which the pipeline and other metallic structures are located. This research studies the rate of deterioration (corrosion rate) of carbon steel pipeline (flow pipe) under five different environmental conditions, coated with different anti-corroding agents, and subjected to different temperatures and pH values. Five Different environmental conditions through which pipelines are laid (Top soil + Fresh water, Sea water bed sand + Sea water, Lagoon water, Seawater, NaCl solution (0.5M)) were simulated in the laboratory. Different seventy gram (70g) samples of the carbon steel pipeline were used as the coupon samples. Red oxide oil paint and tar paint were used as the anti-corroding agents. Water bath was used in regulating the temperature and different concentration of HCL and NaOH were used to vary the pH. Weight loss method was used to calculate the corrosion rates. Results show that carbon steel resists corrosion better when buried in soil than when submerged in water; also the corrosion rate is more in sea water than in the lagoon water of relatively smaller salinity. The rate of corrosion was observed to increase with: increase in temperature, increase in salinity, and increases in acidity and alkalinity. Also the tar paint is more effective as anti-corrodant than the red oxide oil paint when applied to the carbon steel pipeline under same environment conditions. The study successively reduced the corrosion rate of the 70g coupon sample from 0.00127g/day when the sample were suspended in 0.5M, NaCl solution to 0.000104g/day when pipeline coated with tar paint are buried in dry soil.
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    Open Access
    Optimization of Wax deposition in a Sub-Cooled pipeline using Response Surface Methodology
    (Society of Petroleum Engineers, 2015-08-05) Adeyanju, O.; Oyekunle, L.
    Key factors affecting wax deposition in sub-cooled pipelines (wall (coolant) temperature (A), inlet oil temperature (B), and the percentage of wax inhibitors in the crude (C), and oil flow rate (D)) were experimental studied using the fabricated flow loop rig designed to simulate the flow of relatively higher temperature crude oil in sub-cooled pipeline. In an effort to investigate the possibility of minimizing the wax deposits volume in a flow of crude oil in sub-cooled pipeline, response surface methodology (RSM) was used to evaluate the individual and interactive effects of four variables affecting the wax deposits process using central composite design (CCD). It was observed that for the crude oil samples the experimental data highly fitted to the predicted data because of the predicted R-squares is in reasonable agreement with the adjusted R-square. In the laminar-turbulent transition flow regimes (2000 < Reynolds number (Re) > 3000), A, B, C, D,AB, AC, BC, A2, B2, and C2 are significant, as their individual P-value were less than 0.05 by each of the term, while AD, BD,CD and D , are insignificant as their P-values were more than 0.05. While in the laminar flow regime (Re < 2000) the results were similar to that observed in the turbulent flow regime except the flow rate term, (D) which was insignificant (with P-values of more than 0.05) due to insignificant effect of shear dispersion and removal in the laminar flow regime. In applying the response surface methodology central composite design (RSMCCD) in the Minitab-16 software to minimized wax deposit in crude oil flow in sub-cooled pipeline wax deposits were reduced to 64cm in the laminar flow regime and 43cm in the laminar-turbulent transition flow region. The small error percentage between the predicted and actual volume of wax deposit (4.68% in the laminar and 4.55% in the laminar-turbulent transition flow regime: indicated that the software models were valid and accurate in representing the actual experimental values and also in predicting the inhibition of wax deposit within the range studied.
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    Open Access
    Influence of Long Chain Acrylate Ester Polymer as Wax Inhibitors in Crude Oil Pipelines
    (Society of Petroleum Engineers, 2014-08-03) Adeyanju, O.; Oyekunle, L.
    Reliable technical methods for wax build up control in pipelines are critical to the production of crude oil in deep cold water environments. The effectiveness of groups of acrylate ester copolymers of varying alkyl side chains as pour point depressants (PPD) and as wax deposit inhibitors during the flow of crude oil in subsea pipeline was investigated. Three crude oil samples from different oil fields in the Niger Delta of Nigeria were employed. The overall average wax inhibition (OAWI) of 15 – 35% obtained with the acrylate ester copolymers was an improvement compared to the values of 8 – 23% reported from the previous studies. Polymer of similar chemical structures as the crude oil was observed to be effective in the inhibition of wax deposits of such crude oil. Wax inhibition percentages of 25-55% were obtained at high coolant temperatures (above 20 C), but many of the inhibitors exhibited poor performance at low temperatures (below 10 C), with wax inhibition percentage as low as -8%. Addition of demulsifier to the solution of the oil and the polymer was found to improve the wax inhibiting ability. The overall average wax inhibition (OAWI) value of 15.6% was recorded by the use of the demulsifier as against the value of 7.4% without the demulsifier.
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    Open Access
    Prediction of Volumetric Sand Production and Stability of Well-Bore in a Niger-Delta Formation
    (Society of Petroleum Engineers, 2010-08-04) Adeyanju, Olusiji; Oyekunle, Layioye
    Nigeria's Niger-Delta province has been identified as one petroleum system- The tertiary Niger-Delta (Akata- Agbada) petroleum system. Almost all the petroleum resources currently are produced from the sandstone species within the Agbada formation. Also turbidite sand in the upper Akata formation is a potential target in deepwater offshore and currently producing interval onshore. This paper presents a mathematical model to simulate sand production from petroleum reservoir subject to an open-hole completion. A coupled reservoir-geomechanical model was used to predict the volumetric sand production and associated wellbore stability. The model is based on mixture theory with erosion. The Representative Elementary Volume (REV) composes of five phases - solid matrix, fluidized solids, oil, water, and gas phase was chosen. The model also incorporates the reservoir drawdown pressure, rock failure criteria, rock types and field condition. Analytical solution of sand displacement processes is also highlighted. Results show that the magnitude of sand production is strongly affected by the flow rate, the confining pressure, the pressure drawdown and the fluid viscosity. The determined ratio of the productivity index to the saturation of the fluidized solid can be correlated to determine reservoir formation type during sand production, and predicting the wellbore stability. The model has a higher degree of validity for light and medium crude oil flow which possesses moderate lubricating properties, and therefore erosion of sand particles during production highly depends on flow rate.