Chemical & Petroleum Engineering-Scholarly Publications
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- ItemOpen AccessUse of Microcomputers in Monitoring Instruments, Data Acquisition, Analysis and Control(Microprocessors and Microsystems, 1983) Barron, R; Akinola, A. A.; Reid, DThe microprocessor is ideally suited to automating the collection of data, the control of processes and the measurement of important parameters in industry. A number of applications are presented here, where development and research work is carried out using a microcomputer made up of a ZSO microprocessor with additional circuit boards. The applications are in the areas of data acquisition, control and measurement of variables.
- ItemOpen AccessAutomation of a Dust Sampling Train.(Journal of Modelling, Design and Management of Engineering Systems,, 2007) Akinola, A. A.; Muir, D. M.The accuracy of measuring the concentration of particulate matter in flue gas streams by a dust sampling train can be significantly improved or minimized by automating the sampling process using a microprocessor based system. Two situations are presented here, in which a dust sampling train is interfaced via appropriate transducers with a microprocessor and additional circuit boards. The results obtained from this work show that the flue gas sampling process can be automated using a microprocessor-based control system and a sampling train. Using the sampling train developed by the British Coal Utilization Research Association (BCURA) with both the internal and external flow-meter arrangements, the maximum error in iso-kinetic sampling velocity throughout the sampling period did not exceeding 5%.
- ItemOpen AccessThe Application of Peng Robinson Equation of State to Predict Natural Gas Behaviour in Oil based Drilling Fluid(Department of Civil and Environmental System Engineering, University of Benin., 2008-06) Adeyanju, Olusiji; Olafuyi, OlalekanA major problem associated with the use of oil base drilling fluid is the increased difficulty of detecting gas which enters the borehole and dissolves in the drilling fluid. Previous authors have made computer-simulated comparisons between a water-base and an oil-based drilling fluid for one specific field example. However, a method is needed that will permit field personnel to quickly estimate the amount of dissolved gas that can be associated with an observed pit gain for the field conditions present. . In this paper, methods were presented for estimating the swelling of oil based drilling fluid due to dissolved gas. This involves the determination of the formation volume factors of the fluids (oil-gas-drilling fluid mixture) at given subsurface conditions using Peng-Robinson equation of state and hence the detection of the natural gas intrusion into a given well and subsequent calculation of the pit gains. The results were compared with similar but empirically obtained data. The pressure profile for a well at given conditions have also been made thereby aiding the several predictions that will lead to proper fluid flow control.
- ItemOpen AccessNew Multi-Solid Thermodynamic Model for Improved Cloud Point Prediction of Waxy Crudes(Petroleum & Coal Publisher, 2010-07) Adeyanju, O.; Oyekunle, L.A thermodynamic framework is developed for calculating the cloud point also known as WAT (Wax Appearance Temperature) or WDT (Wax Disappearance Temperature) in petroleum mixtures. The method involves the use of experimental data to generate a correction’s correlation for the liquid molar volume shift parameter during liquid-solid equilibrium. Application of the method to the five ternary systems with the 72 equilibrium data points gives an AAD (Absolute Average Deviation) between 0.843 – 0.979. Also, the method gives a better performance in re-producing the experimental cloud point for real petroleum fluids. Its use is simple, accurate and has wide range of validity.
- ItemOpen AccessModeling of Gas-Liquid Stratified Flow in an Inclined Well-Bore and Bends(Nova Science Publishers, Inc., 2010-10) Adeyanju, O.; Oyekunle, L.Multiphase flows modeling in wellbore has always been a problem to the petroleum industry operators. Correlations are presently in use in the petroleum industry, and most of these correlations are obsolete as their application to field data has generated results with unacceptable errors. Most of the existing models proposed to correct these anomalies have always ignored the mass transfer between phases. This has creates serious doubt to the predictive capability of these models. In this study, a one-Dimensional transient state mechanistic model of multi-phase fluid flow in inclined well has been developed. The model is solved numerically to predict the pressure drop as the flow passes through an inclined wellbore and a bend. Results show that the higher the inclination angle the higher the rate of pressure decline in the flow of the fluid to the surface, also a dramatically high pressure drop was observed when the flow passes through a bend. This unexpected high pressure resulting from the change in flow regime from stratified layered flow to slug flow in bend can result in a counter flow of formation fluid back into the reservoir in a low pressure reservoir thereby reducing the fractional recovery from such reservoir. The models predicted the experimental pressure gradient results better than the existing correlations presently in used in the petroleum industry judging from the Average Absolute Deviation (AAD) value of 0.7 compared to AAD value of 1.9 and 2.4 returned by the correlations.
- ItemOpen AccessExperimental Studies of Sand Production from Unconsolidated Sandstone Petroleum Reservoirs in Niger-Delta(Faculty of Engineering, University of Nigeria, Nsukka, 2011-06) Adeyanju, O.; Olafuyi, O.Production of sand during oil and gas exploration causes severe operational problem for oil and gas explorers especially companies producing from unconsolidated formations. Most reservoirs in the Niger-Delta fall in this category. Production oil and gas from such reservoirs has been limited by rate-dependent sand production and fines migration which resulted in near wellbore formation plugging. To prevent this occurrence, controlling the oil and gas flow rate will be of high importance to the oil and gas companies especially the producers operating in the Niger Delta. A physical model which has capacity for both consolidated and unconsolidated samples has been used to simulate the effect of flow rates, confining pressure, pressure drawdown and fluid viscosity on sand production in the Niger Delta. The model was also used to determine the ability of using the flow rate to control the production of sand. Sand sample from an unconsolidated reservoir in the Niger Delta was used in the model. Light and heavy crude oil with laboratory simulated brine was used as fluids as well. Results from the studies showed that the sand production increased as the following parameters; the flow rates, the confining pressure, the drawdown and the viscosity of the formation fluid are increased. The results also indicates that high sand-free flow rates can be achieved if the sand formation is mechanically confined (compacted). Further investigation revealed that sand production can be controlled by managing the flow rate alone when light oil was used while it is impossible to control sand production by managing the flow rate alone when heavy oil was used.
- ItemOpen AccessSimulation of Paraffin Deposition in Petroleum Reservoirs(Nova Science Publishers, Inc., 2011-07) Adeyanju, O; Oyekunle, L.Paraffin deposition within petroleum reservoir during crude oil production can cause a decrease in reservoir performance, consequently the need to predict wax deposition is a major concern to all petroleum producers. The paper presents the development processes of a numerical simulator to model the deposition of Paraffin in the reservoir and it also shows the effects of the Paraffin (wax) deposition on the skin factor in the reservoir. A one-dimensional, three-phase and four-pseudo-component model for paraffin deposition was developed. The paraffin retention by static and dynamic pore surface depositions and pore throat plugging were considered. A fully implicit finite difference numerical scheme was developed and solved by a double iteration procedure. The model when applied to a typical field condition showed that the wax precipitation and consequently deposition to be a near well-bore phenomenon where the pressure gradient is relatively higher than those attainable far in the reservoir. Though little, the paraffin deposition was shown to cause decrease in the porosity, permeability and consequently higher skin in the porous medium especially near the well-bore region. Hence frequent stimulation by heat treatments of the near well-bore region is highly advisable for wells which produce high waxy crude so as to neutralize the skin effects cause by wax deposition in the region.
- ItemOpen AccessThermodynamic Prediction of Paraffin wax precipitation in Crude oil Pipelines” Petroleum Science and Technology(Taylor & Francis Production, 2011-07) Adeyanju, Olusiji; Oyekunle, LayioyeCrude oils are generally very complex chemical systems consisting predominantly of hundreds to thousands of hydrocarbon compounds from simple lowmolecular-weight paraffins to high-molecular-weight waxes. At low temperatures these paraffins precipitate as a wax phase, which may cause the plugging of pipes and many other problems. In this study the cloud point and the amount of the precipitated wax at different temperatures were determined using a modified multi-solid wax model at stock tank conditions and at high pressure for three live crudes and synthetic oil. The model is based on the description of the nonideality of the phases in equilibrium using the Peng-Robinson cubic equation of state for the liquid phase with a modified afunction and the universal quasi chemical (UNIQUAC) equation for the solid phase, which takes into account the effects of temperature, pressure, and composition on the wax precipitation. The model assumes the crystalline nature of wax formed. The experimental data and model predictions reveal that the cloud point decreases with increased pressure and increases when the crude oil is mixed with more light hydrocarbons. The values predicted by the new model show very little deviation from experimental data.
- ItemOpen AccessComputational Accuracy in Calculating In-Duct Iso-Kinetic Sampling Rates in A Sampling Train Using a Microprocessor(Journal of Engineering Research, 2011-09) Akinola, A. A.The microprocessor is the heart of many automated devices in use at the present time. These microprocessors are used mainly in devices where repeated and rapid rates of calculations are required. To achieve' rapid rates of calculation, the microprocessor is programmed directly in machine or assembly language. This paper presents the results of work done in programming a microprocessor in the Assembly programming language to calculate iso-kinetic sampling rates in a dust sampling train. The accuracies of the calculation are examined by comparing the results of the calculations with those obtained when using a mainframe computer. The results show that the accuracy of the calculations is within -4.5 %and +2.5%
- ItemOpen AccessA New Unified Model for Predicting non-Newtonian Viscosity of Waxy Crudes(Taylor & Francis Production, 2012-04) Adeyanju, Olusiji; Oyekunle, LayioyeViscosity determination in the non-Newtonian regime has always been a major problem in the oil industry. This is due to its dependence on the wax precipitated shear and thermal history of the crude oil. The present shear rate dependent viscosity model was developed by applying the theory of suspension rheology. This model is characterized by its capacity to predict viscosities of crude oils with different shear and thermal history and those containing petroleum-based diluents. Once viscosities at two temperatures above the wax appearance temperature (WAT) and apparent viscosity in the non Newtonian regime are known, viscosities or apparent viscosities at any temperature above the gel point can be determined by using the model together with the concentration of precipitated wax at the specified temperature. Verification of the model by using two Nigerian crudes with different shear and thermal histories and two crudes obtained from the literature shows that the model predicts viscosities with an average absolute deviation of 4.9%.
- ItemOpen AccessA New Unified Model for Predicting non-Newtonian Viscosity of Waxy Crudes(Taylor & Francis Production, 2012-04) Adeyanju, Olusiji; Oyekunle, LayioyeViscosity determination in the non-Newtonian regime has always been a major problem in the oil industry. This is due to its dependence on the wax precipitated shear and thermal history of the crude oil. The present shear rate dependent viscosity model was developed by applying the theory of suspension rheology. This model is characterized by its capacity to predict viscosities of crude oils with different shear and thermal history and those containing petroleum-based diluents. Once viscosities at two temperatures above the wax appearance temperature (WAT) and apparent viscosity in the non Newtonian regime are known, viscosities or apparent viscosities at any temperature above the gel point can be determined by using the model together with the concentration of precipitated wax at the specified temperature. Verification of the model by using two Nigerian crudes with different shear and thermal histories and two crudes obtained from the literature shows that the model predicts viscosities with an average absolute deviation of 4.9%.
- ItemOpen AccessHydrodynamics of Sand-Oil-Gas Multiphase Flow in a Deviated Petroleum Well(Nova Science Publishers, Inc., 2012-05) Adeyanju, O.A calculation method for predicting pressure profiles along the wellbore based on easily obtainable wellhead parameter has been the preferred method. But, the predictive capability of the existing correlations is a thing of concern. This is due to the inability of the existing models and correlations to account for the presence of the sand particles in the flow stream; also the requirement for the well to be shut-in in order to acquire the needed parameters is counter productive. These inadequacies were corrected in the proposed model. Results showed that the average pressure drop in the multiphase fluid flow using the proposed model is higher than the pressure drops determined using existing models and correlations. The effects of the fluid density, viscosity and velocity on the sand particles lifting were also investigated and results showed that the sand particles suspension and lifting were improved by higher fluid velocity and density and lower fluid viscosity (i.e. higher Reynolds number). Validation of the proposed model with field data showed that the model predicts the field BHP data better than any of the existing models and correlations, based on the Average Absolute Deviation (AAD) value of 6.53 returned by the proposed model compared to AAD value of between 13.56 and 24.67 returned by the existing models and correlations.
- ItemOpen AccessAn Experimental study of Rheological Properties of Nigeria Waxy Crude Oil(Taylor & Francis Production, 2012-08) Adeyanju, Olusiji; Oyekunle, LayioyeNigerian crude oils are known for their good quality (low sulfur, high American Petroleum Institute gravity). However, similar to any other paraffinic-based crudes, most Nigerian crudes contain moderate to high contents of paraffinic waxes. These waxy crudes exhibit non-Newtonian flow behavior at temperatures below the cloud point because of wax crystallization. In order to accurately predict flowing and static temperature profiles, design waxy crude oil pipelines, evaluate flow interruption scenarios, and start up requirements in the handling of waxy crude oils, the effect of temperature and shear rate on the rheology of crude oils must be determined. This work presented some experimental results on the rheology of two waxy crude oils produced from different Nigerian oil fields. A Brookfield DV-III ultraprogrammable rheometer (Brookfield Engineering Laboratories, Middleboro, MA) was utilized. The temperature dependence of rheological properties and thixotropy of these crudes were investigated. The influence of some petroleum-based diluents to depress the wax appearance temperature (WAT), their effect on the thixotropic/yield pseudoplastic behavior of two Nigerian crudes were studied and it was observed that lower wax content crude has higher tendency to regain its cohesive lattice bonding (yield strength) when left undisturbed for some days at its gel point after agitation. The experimental results showed that the addition of petroleum-based diluents to the lower wax content crude oil leads to its lost some of its yield strength regaining capacity.
- ItemOpen AccessModeling and Simulation of Scale Deposition during Water-flooding in Porous Media(Nova Science Publishers, Inc., 2012-11) Adeyanju, O.Mineral scale deposition within the reservoir due to incompatibility of the injected and the formation water can cause a significant decrease in reservoir performance. Few documentations of the damage cause by scale deposition to reservoir flow performance are available in the literature. In this paper a fully implicit numerical model was developed to model the deposition and concentration profiles of scales formed in the formation. The simulated results conform well when compared to the developed analytical solution to mimic the mineral scale deposition and concentration profiles. The model ability to shows the effects of changing porosities not acknowledged by the analytical model confirmed the effectiveness of the developed model. The results showed that the effect of permeability and porosity reductions is prominent in the near well-bore regions of the injection well. Also the higher the concentrations of the mineral scale in the mixture of the injected and formation water the higher the degree of formation damage. Hence efforts should be made to test the compatibility of the injected and formation water before embarking on a water-flooding project to prevent excessive damage to the reservoir. This will minimizes productivity reduction during the flooding.
- ItemOpen AccessComputer Aided Design of Circular Clarifiers,(Journal of the Nigerian Society of Chemical Engineers, 2013) Odediran, E. T.; Ayo, D. B.; Akinola, A. A.An algorithm was developed for the design of primary circular clarifier for Wastewater treatment. Three computer programs were developed using Microsoft Excel, FoxPro and MATLAB respectively, all based on the algorithm. Computational Results from the three programs were not significantly different from those carried out manually. The algorithm was validated by feeding operational data (influent and effluent conditions) from the Primary clarification unit of the City of Springfield Wastewater Treatment Plant (WWTP), Ohio, USA into the three computer programs. The results of calculations from the computer programs using data from the Springfield WWTP were not significantly different from the design data of the WWTP.
- ItemOpen AccessExperimental Study of Wax Deposition in a Single Phase Sub-Cooled Pipelines(Nova Science Publishers, Inc., 2013-08) Adeyanju, O.; Oyekunle, L.The ability to determine the severity of wax deposition is an extremely important issue, particularly in the design and development of deepwater oilfields. Though much progress has been made in the last decades to better the understanding of this complex process, yet the ability to accurately account for all the factors that affect wax deposition are currently not in existence in the wax simulators used presently in the industries. In this study an experimental methodology constructed to simulate wax deposition process was employed to investigate the influence factors controlling paraffin wax deposition to the pipe wall surface (namely, inlet oil temperature, inlet coolant temperature, oil flow rate and the wax content). Series of tests were designed to determine the effects of these influence factors on the wax content in the deposit. The experimental results revealed that the amount of wax deposited initially increases with time, attained a maximum value and gradually erode off. Also it was discovered that the wax deposition decreases with flow rates and also with the temperature difference between the flowing oil and the pipe wall, when the oil temperature is above its Wax Appearance Temperature (WAT), while the reverse is the case when the oil temperature is below its WAT. The study also established that shear dispersion, defined as the movement of wax crystals towards the pipe wall as a result of the velocity variation along the radial direction during oil flow in the pipe ignored in most of the existing models used in the existing wax deposition commercial codes was found not to be inconsequential. The flow rate rather than the flow regime was also discovered to responsible for the shear stripping of wax deposit at the wall. This experimental observation will provide a reference point and an insight for further study on wax deposition in actual pipelines. This is particularly so for oil characterized by high wax content and high gel point temperature like those produced from most fields in Nigeria’s Niger Delta.
- ItemOpen AccessOptimization of Natural Gas Transport in Pipeline(Centre for Advanced Training and Research, 2013-10) Adeyanju, O.; Oyekunle, L.Transportation of natural gas is a very important aspect of the oil and gas industry and as such, it must be done with a much efficiency. Pipelines has been recognized as the most economic, effective and safest way of transporting natural gas. A lot of capital is needed, due to cost of pipeline, compressor stations and also in its maintenance. Therefore in order to minimizing cost, optimization of natural gas transportation processes is necessary. In this study, optimization procedure of natural gas transportation network was developed using a workable procedure adapting the Generalized Reduced Gradient algorithm. It determines the optimum economical conditions natural gas can be transported through series of pipeline and compressors station. The model developed when applied to the Excravos Lagos pipeline network showed that total cost of flowing natural gas depends on the amount of gas to be transported and also on the outlet pressure required. Results show that depending on the require flow rate, some installed compressors need to be inactive for effective cost reduction. The required diameters to meet the corresponding demand (Flow rates) are presented for the future upgrade of the facilities. Also comparison of different gas flow equations showed that the optimum network configuration for panhandle A and B are almost the same, but for Weymouth equation, it widely varies. The developed model can be extended to treat much larger and more complex network.
- ItemOpen AccessA Proposal for the Management of Plastic Packaging Waste(Journal of Environmental Science, Toxicology and Food Technology, 2014) Akinola, A. A.; Adeyemi, I. A.; Adeyinka, F. M.An Environmental Impact Assessment study was performed using the Life Cycle Assessment (LCA) technique for a range of plastic packaging waste disposal technologies, to determine which waste management strategy has the potential to provide significant environmental benefits over existing waste management strategies. Comparisons were made between the various technologies; a number of scenarios are considered to build up supply chains for the disposal process. The Life Cycles of Plastic packaging waste disposed via the Landfill, Incineration and Integrated Plastic Waste Management (IPWM) methods were compared and their environmental burdens calculated using the Eco-indicator 99 method. The Single Score and Damage Assessment revealed that IPWM offers the most significant environmental benefits. Characterization plots of the effect on Climate change , Ozone layer depletion ,Eco-toxicity , Respiratory organic and inorganic gases, Carcinogens , Radiation, Acidification/ Eutrophication, Land use and Minerals also confirmed that environmental benefits were most significant with IPWM.
- ItemOpen AccessRefractance Window™ Drying of Red Onions (Allium Cepa)(Journal of the Nigerian Society of Chemical Engineers, 2014) Akinola, A. A.; Lawal, S. O.; Osiberu, A. S.A Refractance Window dryer was fabricated and used to study the drying characteristics of red onions (Allium Cepa). The data for the drying of the 1mm, 2mm and 3mm sized shreds of red onions were obtained experimentally and the drying curves and mathematical model that best fit the drying data were determined. The quality of the dried red onion powder was determined and compared with dried onion powder obtained from the local supermarket. The results obtained, established that size affects the drying time of the onion samples. The 1mm sized shreds dried fastest reducing from a moisture content of 7.19kg water per kg dry solids to less than 0.2kg water per kg dry solids within 40 minutes of drying. The time of drying increased with size. Of the 13 Thin-layer drying curve models studied, the regression results showed that the Haghi and Ghanadzadeh model best describes the drying curve of the 1mm, 2mm and 3mm sized shreds with the highest coefficient of determination (R2) values of 0.99196, 0.98570 and 0.99523 respectively. The dried onion powder had a Bulk density of 0.4501 grams/ml while those of the market onion powder were 0.4616 grams/ml.
- ItemOpen AccessA New Model for the Prediction of Real Time Critical Drawdown Sand Failure in Petroleum Reservoirs(Taylor & Francis Production, 2014-07) Adeyanju, Olusiji; Oyekunle, LayioyePetroleum producers are now realizing the risk of failure in petroleum reservoirs and consequently sand production is now a dreaded process in the industry. As a result, failure analysis of reservoirs rocks for sanding potential prediction purposes has become a routine activity more than ever before. Due to the high cost and operational and safety implications of the risk of sand failure, the efficient management of these risks for field operation optimization requires a reliable failure model. Most of the existing models failed to capture the real time failure of the reservoir’s sand, and those that tried to capture the real time failure criterion required parameters that are difficult to acquire. The developed model modified the Griffitti rock failure criterion using McClintock and Walsh hypotheses to predict the current critical drawdown pressure of petroleum reservoir. The required parameters for the application of the developed model can be easily determined. The error analysis from the model in relation to the field data when compared with those of Oluyemi and Oyeneyin’s model showed that the developed model gives better predicting ability
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