Nigerian Journal of Technological Development <p>The Nigerian Journal of Technological Development is now a quarterly publication of the Faculty of Engineering &amp; Technology, University of Ilorin, Ilorin, Nigeria. It publishes original high-quality articles focusing on all aspects of Engineering and Applied Sciences in March, June, September and December. Manuscripts are double-blind peer-reviewed and if found suitable, published according to the subject matter as a <strong>Research Paper, Review Paper or a Technical Note.</strong></p> <p>Other websites associated with this journal:&nbsp;<a title="" href="" target="_blank" rel="noopener"></a></p> Faculty of Engineering & Technology, University of Ilorin, Ilorin, Nigeria en-US Nigerian Journal of Technological Development 0189-9546 <p>In accordance with the Copyright Act of 1976, which became effective January 1, 1978, the following statement signed by each author must accompany the manuscript submitted: "I, the undersigned author, transfer all copyright ownership of the manuscript referenced above to the Nigerian Journal of Technological Development, in the event the work is published. I warrant that the article is original, does not infringe upon any copyright or other proprietary right of any third party, is not under consideration by another journal, and has not been published previously. I have reviewed and approve the submitted version of the manuscript and agree to its publication in the Nigerian Journal of Technological Development." A copyright transfer form may be downloaded from the NJTD Website ( Author(s) will be consulted, whenever possible, regarding republication of material. All authors must have access to the data presented and the authors and sponsor (if applicable) must agree to share original data with the editor if requested.</p> An Improved Model for the Prediction of Liquid Loading in gas Wells using Firefly and Particle Swarm Optimization Algorithms <p>Liquid loading is an undesired phenomenon in gas wells that occurs when producing wells attain a flow rate below which liquid will not be able to flow to the surface. The inability of the energy from the gas to transport the liquid to the surface causes back flow and eventual accumulation of liquid at the wellbore. This is characterised by intermittent flow, which, if left unchecked, can eventually kill the well. An effective and reliable predictive method must therefore, be employed. In this study, improved models based on data set from condensate/water in a gas well were developed by applying firefly (FA) and particle swarm optimisation (PSO) algorithms. The results showed that the model developed out perform many of the existing models. The models predicted liquid loading in gas well at 86% level of accuracy compared to the 81% highest possible from published models. Although, the FA and PSO models predicted liquid loading at higher accuracy compared with Turner and Coleman models for higher wellhead pressure systems, the Coleman model appeared to perform better in the prediction of critical gas rate for low-pressure systems. However, the developed model can significantly improve the prediction of liquid loading in gas wells at a higher reliability and accuracy levels. Thus, the proposed models can be a veritable tool for accurately predicting liquid loading in gas wells.</p> A.B. Ehinmowo I.O. Adeboye M.A. Aliyu Copyright (c) 2022-02-09 2022-02-09 18 4 258 267 10.4314/njtd.v18i4.1 Investigation of <i>Alkanol-Amine</i> Solvents and their Blends for CO<sub>2</sub> Removal from Natural Gas using Aspen-Hysys <p>The removal of carbon dioxide (CO<sub>2</sub>) from natural gas is vital towards meeting pipeline sales gas specifications and evading operational complications during the liquefaction of natural gas. Therefore, the removal of CO<sub>2</sub> from natural gas is necessary for the efficient utilization of natural gas and for the reduction of global CO<sub>2</sub> emission. It is also vital for the effective liquefaction process in the liquefied natural gas project A common and widespread technique used at natural gas plants in Nigeria is the removal of carbon dioxide (CO<sub>2</sub>) from natural gas through chemical absorption using alkanolamine solutions. In this research, an amine sweetening process is simulated using Aspen HYSYS V10 with a typical Nigerian natural gas composition. The simulation is used to investigate four different kinds of amines and their blends (mixed amines). The investigated amines are Monoethanolamine (MEA), Diethanolamine (DEA), Diglycolamine (DGA) and Methyldiethanolamine (MDEA) while the blends are MDEA + MEA, MDEA + DEA and MDEA + DGA. Results obtained from the simulation show that the mixed amine “MDEA + MEA” with lean amine strength of 11% MEA and 39% MDEA, absorbs 99.97% of CO<sub>2</sub> present in the gas and hence, amine blends absorb carbon dioxide from natural gas better than the individual amines. It was also concluded that increasing the composition of the primary or secondary amine while decreasing the composition of the tertiary amine in the lean amine solution (amine blend) led to an increase in the amount of CO<sub>2</sub> being absorbed. The study provides useful information on the absorption of CO<sub>2</sub> using alkanolamine solvents and their blends in a standard amine sweetening plant.</p> O.A.A. Eletta D.T. Awotoye A.A. Zubairu Copyright (c) 2022-02-09 2022-02-09 18 4 268 278 10.4314/njtd.v18i4.2 Comparative Analysis of Satellite and Regulatory based Gas Flare Volumes in the Niger Delta Region <p>Associated gas flaring leads to severe environmental issue, and the importance of effective monitoring and accurate recording of this operation has been a subject of discussion in the petroleum industry. This research used statistical methods to compare the flare volume of both Regulatory Agency records and Satellite-based estimates to determine the accuracy and reliability of estimates. Seven prolific offshore oilfields from the Niger Delta region were considered for this research and the monthly records of flare volume for 2016, 2017, 2020 and 2021 were used to investigate the comparative relationship that exists. The result revealed that the mean flare volumes of four oilfields (Agbara, Bonga, Erha and Usan) did not differ significantly but Abo and Akpo oilfields revealed that estimates from the satellite were significantly greater than the regulatory reports, while the estimates from Agbami oilfield supported the contrast. The Pearson correlation analysis also revealed that a moderately strong positive relationship exists between the estimates for the sampled oilfields. The study further examined the discrepancies between both methods of gas flare measurements and proffered solutions on how these discrepancies could be resolved and recommended a strategy for monitoring natural gas venting.</p> P.N. Ndunagu O.F. Joel A.A. Oji Copyright (c) 2022-02-09 2022-02-09 18 4 279 287 10.4314/njtd.v18i4.3 Production of Reinforced Polyester Composite from Okra Fibre and Sawdust <p>This research presents properties of okra and sawdust reinforced polyester composite. The compatibility of the simple woven okra and sawdust with polyester was enhanced with stearic acid treatment. FTIR analysis confirmed decrease in hydrophilicity of the fibre and dust. Six composite samples; pure polyester, sawdust reinforced polyester composite, okra reinforced polyester composite, 10% sawdust in okra fibre reinforced composite, 20% sawdust in okra fibre reinforced composite and 30% sawdust in okra fibre reinforced composites were fabricated and characterized. The morphological analysis showed that the homogeneity of polyester in the samples reduces with increase in sawdust filler (10-30 wt%). Water absorption was highest (1.6%) in 30% sawdust in okra. The densities of all the composites were between 3.5 – 4.5 kg/m<sup>3</sup>. The sawdust reinforced composite recorded low impact energy of 0.25 J while the woven okra fibre reinforced polyester recorded the highest impact energy of 9.9 J. Hardness property reduced as the biomass content increased. Unreinforced polyester recorded the highest average elongation of 25% (1400 µm) and reduced elongation as filler increased. The storage modulus was highest for unreinforced composite at 40<sup>o</sup>C but as the temperature reached 81<sup>o</sup>C the storage modulus of unreinforced polyester dropped lower than the sawdust composite. The damping factor (1.41) was highest for 20 wt% sawdust/okra polyester composite. This research concludes that sawdust and okra are suitable for lightweight and energy damping materials in automobile applications.</p> T.K. Bello M.O. Oladipo A. Idris F.B. Beka U.P. Unachukwu A. Bukar Copyright (c) 2022-02-09 2022-02-09 18 4 288 295 10.4314/njtd.v18i4.4 Performance and Microstructural Evaluation of Asphalt Concrete Produced with Hydrated Lime, Glass Powder and Cement Modifiers <p>The increasing axle load arising from the growth in vehicular volume reduces the durability of road pavement, hence the need to further strengthen the road pavement. This research focuses on the determination of the performance of asphalt concrete in relation to the microstructural characteristics of the asphaltic concrete produced with hydrated lime, glass powder and ordinary Portland cement as modifiers. Asphalt Concrete (AC) mixes were prepared with Dangote 3X cement (D3C), Lafarge Superset cement (LSC), hydrated lime (HL) and glass powder (GP) in varying proportions of 20, 40, 60, 80 and 100%. The stability and morphology of the asphalt concrete produced were determined using Marshall stability test and scanning electron microscopy respectively. AC containing GP and HL showed maximum stability of 3.61 kN and 4.01 kN respectively. The maximum stability values obtained for the samples containing D3C and LSC as fillers are 4.21 kN and 5.10 kN respectively; these stability values meet the minimum Marshall Design criteria of the Asphalt Institute. The microstructural analysis of the asphalt concrete samples showed that GP has the lowest maximum pore value of 4.39 µm<sup>2</sup> in which the inter-particulate spaces in the AC produced with GP are small and the agglomeration of the particles indicated that they are densely packed and are characterized with good strength.</p> E.O. Olukanni O.J. Oyedepo A.M. Ajani Copyright (c) 2022-02-09 2022-02-09 18 4 296 301 10.4314/njtd.v18i4.5 Evaluation of the Strength Properties of Asphalt Concrete using Natural Fibres as Reinforcing Additives <p>The period of maintenance and rehabilitation of asphalt concrete pavement can be increased by using fibres as reinforcement in a bituminous mix. Shredded Sisal fibre (<em>Agave sisalana</em>) and Sponge gourd (<em>Luffa cylindrical</em>) were used as reinforcements in bituminous mix. The fibres were added to hot mix asphalt in varying proportion of 0.1%, 0.2%, 0.3%, 0.4% and 0.5% by weight. The strength of fibre reinforced asphalt concrete was determined by conducting Marshall stability test. The tensile strength on 40 strands of fibre gave 167.43 N/mm<sup>2</sup> and 24.58 N/mm<sup>2</sup> for Sisal fibre and sponge gourd fibre respectively. Marshall Stability test results indicated that Sisal fibre gave minimum and maximum values of 4.46 kN and 5.54 kN, respectively, which exceeded the 3.5 kN minimum stability value for wearing course in the Nigerian General Specification for Roads and Bridges. The flow values obtained showed that the flow values are more than the 4 mm minimum value except for 0.1 sisal fibre dosage which has a value of 3.99 mm. The high flow values obtained was an indication of the reinforcing effects of the fibres which made the asphalt concrete stronger and hence have great resistance to plastic deformation.</p> O.J. Oyedepo E.O. Olukanni A. Alalade A. Amoko G. Oluwadare O. Ayanda Copyright (c) 2022-02-09 2022-02-09 18 4 302 311 10.4314/njtd.v18i4.6 Assessment of a New Dam Site for Water Supply Potential in Bauchi Metropolis, Nigeria <p>The maximum yield of 90,000 m<sup>3</sup> /day from the existing Gubi dam in Bauchi will barely meet the water demand beyond 2030 at an average water use of 100 litres per capita/day. For higher water demand of up to 250 litres per capita/day expected in an urban centre, the existing dam capacity is inadequate, and the demand should grow to 253,102 m<sup>3</sup>/day by 2037. This is the rationale for this study, which showed the feasibility of a new dam through technical reviews and analysis of topography, hydrology of the site, field and laboratory investigations, computer analyses and designs. Hydrologic simulation of rainfall-runoff processes for 57 years of rainfall data using the Soil Conservation Service (SCS) method gave an annual runoff volume of 59 Mm<sup>3</sup> on a stream in Miri, which can be harnessed to assure adequate water supply in the metropolis. This will require the construction of a 25 m high embankment dam. Topographic survey and analysis indicated that the proposed site has good water retention capability. Although net flow adjustment analysis showed a high evaporation loss of up to 13.5 Mm<sup>3</sup> annually, seepage loss is expected to be small in view of the underlying basement complex rock formation.</p> O.B.E. Salau A. Salaudeen B.A. Gana I. Zubairu S.I. Musa Copyright (c) 2022-02-09 2022-02-09 18 4 312 321 10.4314/njtd.v18i4.7 Cultivation and Processing of Microalgae for Its Sustainability as a Feedstock for Biodiesel Production <p>Microalgae are becoming sustainable alternative feedstocks to food crops for biodiesel production which can also solve the problems associated with the use of fossil fuels. However, several challenges about microalgae’s cultivation, harvesting, pre-treatment and extraction processes as well as the technology of biodiesel production affect its sustainability. This study proffers solutions to these challenges and recommended that hybrid culture systems with genetically engineered microalgal species would overcome the challenges of cultivation. The coagulation/flocculation method was adjudged the best harvesting process of the microalgae for its sustainability for biodiesel production. The pre-treatment by ultrasound coupled with enzymatic extraction was suggested best, due to their numerous advantages over other methods. A novel integrated ultrasound-enzyme-enzyme in-situ pre-treatment-extraction-transesterification design is considered a sustainable approach to utilising microalgae biomass for biodiesel production. The study concludes that the microalgae biomass is more than sufficient to meet the global energy demand and can be economically harnessed as a sustainable feedstock for biodiesel production.</p> <p>HIGHLIGHTS</p> <p>•Microalgae contain sufficient characteristics for their sustainability for biodiesel production.<br>• Implementation of genetic strategies of microalgal species by cultivating in a hybrid system is the key to microalgae sustainability.<br>• Harvesting of microalgae by coagulation/flocculation method would promote its efficient lipid recovery.<br>• Microalgae are novel feedstocks with a rigid cell wall, its lipid extraction requires the use of effective and efficient pretreatment.<br>• The ultrasound-enzymatic extraction and enzymatic transesterification in an in-situ process can sustainably utilise microalgae biomass for biodiesel production.</p> E.O. Ajala M.A. Ajala G.S. Akinpelu V.C. Akubude Copyright (c) 2022-02-09 2022-02-09 18 4 322 343 10.4314/njtd.v18i4.8 Analysis and Performance Evaluation of ThreePhase Induction Motor Model with Zero Quadrature Axis Flux Component <p>Modeling of three phase induction motor has been extensively discussed in literature. Several models have been developed and applied by different authors to solve different problems. This paper presents a differentmodel of the symmetrical three phase induction motor in which there is an alignment of the direct axis component of the rotor flux vector to direct axis of the reference frame. The alignment reduces the quadrature axis flux component to zero, removes the dependencies associated with the d-q components of the stator current and simplifies the rotor dynamics. The model is not commonly used in literature to study motor behavior when vector control is not the objective. The model is analyzed in the synchronous reference frame and simulated. Simulation results for torque, speed and flux in the motor are presented. Also presented are the waveforms of stator voltages and currents in both the d – q and a-b-c reference frames and the rotor d-q axis currents. These results provide a correct description of the three phase induction motor behavior under load and no-load conditions.</p> G.A. Olarinoye M.F. Akored S.N. Okhuegbe Copyright (c) 2022-02-09 2022-02-09 18 4 344 351 10.4314/njtd.v18i4.9 Flaring Intensity Monitoring: Applications at Different Levels of Nigerian Petroleum Upstream Industry <p>Flare volume measurement has been the sole yardstick for tracking flare gas reduction progress and provides a single view of monitoring in the context of its use. In this study, an alternative method was introduced to broaden the perspective of flare gas monitoring. Flaring intensity is a simple and effective measure for tracking flare gas reduction. Flaring Intensity index was applied in different levels of flare volume estimation, namely Oilfield, Oil Company, Petroleum Upstream Contract and Country. Nigerian Petroleum Production data were sourced from regulatory reports and satellite data from 2012 to 2015 and 2018 annual reports. The results revealed that Nigeria’s flaring intensity is on the decline due to exogenous factors and it illustrates flaring intensity as a comparative and benchmarking tool for gas flare performance at various hydrocarbon production levels. The study also inferred that improved flare gas measurement, transparency in reporting, robust regulation and increased gas handling infrastructure were necessary in order to mitigate flaring in Nigeria to achieve the 2030 Zero Routine Flaring target.</p> P.N. Ndunagu O.F. Joel A.A. Oji E.E. Alaike Copyright (c) 2022-02-09 2022-02-09 18 4 352 360 10.4314/njtd.v18i4.10