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Bitumen is a complex mixture of organic molecules comprising mainly of hydrocarbons and it is use as a binder in constructions and in tarring of roads. This study was conducted to investigate some of the physical and mechanical properties of bitumen modified with natural rubber crumb (NRC) when cured and when left uncured. Five different blend ratios (2%, 6%, 10%, 14% and 18%) NRC by mass of the bitumen were used as modifiers. Penetration, softening point, Viscosity and Ductility tests were conducted on the ordinary bitumen and the blends. These basic property tests were used to explain the effect of natural rubber crumb and vulcanization on the binder (bitumen). Tests conducted gave a penetration value for ordinary bitumen 60/70 grade as 50.0mm and the value decreased to 32.5mm, 20.5mm, 19.8mm, 18.0mm and 17.4mm as the blend ratio increased from 2% to 18% respectively for the vulcanized mix and 46.0mm, 40.0mm, 36.0mm, 38.0mm and w41.0mm for the un-vulcanized blends as the blend ratio also increased from 25 to 18%. For softening point, 400C was enough to soften ordinary Bitumen but as the blend ratio increased from 2% to 18%, the temperature increased to 53.00C, 56.00C, 59.00C, 62.00C and 66.00C respectively for the vulcanized mix and for the uncured, 50.00C, 52.00C, 48.00C and 46.00C respectively. As the blending ratio increased, Viscosity also increased from 8seconds for the ordinary bitumen to 12sec, 23sec 50sec, 72sec and 84sec for the vulcanized mix and 10sec, 15sec, 27sec, 39sec and 48sec for the un-vulcanized mix respectively. Similarly, ductility also increased from 105cm for the ordinary bitumen to 124.0cm, 136.0cm, 151.0cm, 178.0cm and 200cm for the vulcanized blends and 115.0cm, 120.0cm, 129.0cm, 139.0cm and 152.0cm for the un-vulcanized mix respectively. These findings shows that NRC can be used to influence the chemical and physical properties of bitumen binder.

The utility of Nru clay for industrial application, which was taken from the Nsukka local government area in Enugu State, Nigeria, is assessed in this study for its physical and chemical properties. The clay was investigated chemically which showed SiO 2 51.2%, Al 2 O 3 18.3% as the predominant constituents while other metallic oxides such as Fe 2 O 3 5.3%, MgO 2.2%, Na 2 O 1.8%, CaO 1.4%, K 2 O 1.3% and MnO 0.7% were present in considerable proportion. The physical and mechanical analysis acknowledged a range in the linear shrinkage (4.17 - 6.25%), total shrinkage (7.8 - 10.2%), apparent porosity (36.92 – 26.58%), apparent density (2.59 - 2.37 g/cm3), bulk density (1.63 - 1.74 g/cm3), water absorption (22.64 – 15.33%) and modulus of rupture (6.70 – 9.15 kg/cm2) with an increase in firing temperature from 900°C to 1200°C. Nru clay can withstand heat without melting or deforming at temperature up to 1200 °C and exhibited reasonable plasticity with a modulus of plasticity of 1.42. We can infer from our investigation that Nru clay is a potential raw material for industries in the production of ceramics, high melting clays, fired bricks, and paints. Alternatively, the clays’ properties can be tailored to achieve superior physical and mechanical properties by enhancing them with additives. Therefore, it can be employed to cushion the exorbitant cost of importing clay minerals from other nations.

In this work, the adsorption of ciprofloxacin onto yam peel biosorbent was studied by batch method. The equilibrium isotherm analysis of the adsorption process was evaluated to provide insight into the removal mechanism. A decrease in the percentage removal (75.0 – 60.8%) and an increase in adsorption capacity (6.0 – 24.3 mg/g) with an increase in ciprofloxacin concentration from 20 – 100 mg/L was obtained. The isotherm was analyzed by the Langmuir, Temkin, Freundlich, and Scatchard models, and the best fit was obtained for the Freundlich model with a R2 of 0.9918. The separation factor in the range of 0.238 – 0.609 and the Freundlich adsorption intensity of 1.492 indicated a favorable adsorption of ciprofloxacin on yam peel. A monolayer adsorption capacity of 42.81 mg/g was obtained for yam peel which was higher than other efficient adsorbents. The Scatchard model gave a linear fit to the uptake data with R2 of 0.9653 and sum square error of 0.008. The isotherm analysis revealed complex adsorption involving multi mechanisms in the overall process. The results of this investigation showed that yam peel could be utilized as an efficient agricultural waste for the adsorption of ciprofloxacin from wastewater.

The physico-chemical and microbial examination of Ajali River in Ezeagu Local Government Area (LGA) of Enugu State, South-eastern Nigeria, were carried out to assess the characteristics of the water for potability. Water samples were collected from three sampling points, including the one close to the brewery effluent discharge into the river and two different points that were affected by non-point sources. Altogether, eighteen samples were collected for two years during the dry, early and late rainy seasons. The physico-chemical, as well as microbial analyses of the samples, were determined following the standard methods. Significant spatial and seasonal variations (p

The energy demand is on the global increase as the world economy is increasing steadily. Hence, the need to develop energy-saving technology with local raw materials and abundant waste materials becomes paramount. The mixtures of Enugu Iva-pottery clay, Nsu clay and PKS were evaluated to improve the quality of locally produced refractory for pyro-processing industries. The chemical and mineralogical composition of the PKS and the clay were determined. Eight recipes were made by varying PKS with quartz from 5 to 35% and produced by the wet pressing technique, then fired to 1200 °C and 1300°C respectively. The mechanical properties were determined by the Modulus of Rupture test, also, the bulk density, linear shrinkage, total shrinkage, apparent porosity, water absorption and thermal efficiency tests of the produced refractories were ascertained. The recipe with 15% PKS sintered well at 1300°C and gave the best optimum results of 1.76g/cm3 bulk density, 6.49% linear shrinkage, 21.384% apparent porosity, 20 cycles of spalling tests at 1300 °C. The results comply well with the standards of refractory properties. The PKS additives have shown significant improvement in the properties of the locally produced refractories and waste control; hence, can promote sustainable development of the local pyro-processing industry.

The efficiency of various benzimidazole derivatives as mild steel corrosion inhibitors in HCl and H2SO4 medium was evaluated using quantum chemical methods. The AM1 semi-empirical method and Density Functional Theory (DFT) at the B3LYP/6-31G* level were used. The orbital energies (EHOMO and ELUMO), Separation Energy (ELUMO-EHOMO), Dipole moment (µ), Log P, Polarizability, molecular volume, molecular weight, Hardness (η) and Softness (S) are the computed quantum chemical characteristics linked to inhibitory efficiency. There was a strong link between quantum chemical parameters and experimental inhibition efficiency. The findings revealed that the Inhibition Efficiency was linked to a number of quantum chemical factors. The 2-mercaptobenzimidazole derivative had a higher Inhibition Efficiency (IE) than the other benzimidazole derivatives, according to the results.

This investigation is on the treatment of a fibre-cement industry effluent (FCIE) using activated carbon (AC) adsorbent prepared by chemical activation (60% phosphoric acid) of Gossweilerodendron caesalpinoideae (GC) stem waste. The GCAC adsorbent was characterized by determination of the proximate and functional properties. The chemical groups, morphology and mineral phases of the GC stem waste and GCAC were studied by FTIR, SEM, and XRD methods, respectively. Kinetic and thermodynamic studies were carried out using total dissolved solids (TDS) as evaluating parameter. Effects of adsorbent dosage (5-40 g/L), contact time (0-60 min), and temperature (20-40 °C) on the effluent decontamination were investigated. Results from the characterized supernatant showed up to 97% removal of the contaminants using 40 g/L of GC adsorbent at effluent pH 7.4. The concentrations of TDS obtained by U-V spectrophotometric analysis were fitted to pseudo-first and pseudo-second order, Elovich and intraparticle kinetic models. The adsorption followed the pseudo-second order rate equation. Obtained free energy and enthalpy of adsorption values indicated non-spontaneous and endothermic adsorption. The study affirmed that the bioadsorbent, GCAC can be used for FCIE treatment.

More than 70% of oil-producing wells require some form of artificial lift to increase the flow of fluids from subsurface to the surface when a reservoir no longer has sufficient energy to produce at economic rates. This situation has been observed in the Niger Delta oil wells over the past years and has caused the abandonment of reservoirs with a significant volume of hydrocarbon. Data from two oil wells that could not flow naturally to the surface have been obtained from an oil company operating in the Niger Delta. The arm of this study is to optimize the production of two oil wells using an artificial lift system. To increase production and extend the life of these wells, artificial lift projects were considered. This was done with the aid of Integrated Production Modelling (IPM) tool in Petroleum Expert suite. Two wells were simulated using the obtained data, and their production performances were evaluated. The well’s production outputs were optimized using artificial lift systems, that is electric submersible pump (ESP), hydraulic pump (HP), and gas lift (GL). The results obtained showed that the ESP wells have the highest oil production rate compared to GL and HP respectively. An economic analysis was carried out using Net Present Value (NPV), Profitability Index (PI) and Internal Rate of Return (IRR). In terms of economic comparison, ESP is the most viable project with the highest NPV, PI and IRR Hence, the ESP technology proved to be the best technology for sustaining a high production rate, increasing revenue and proved to be economically viable in Niger Delta oil fields.

Fluid-flood and other improved oil recovery techniques are becoming prominent in global petroleum production because a large proportion of production is from mature oil fields. Although water flooding and gas injection are well established techniques in the industry, several of the screening criteria in literature are discipline which could sometimes be subjective. This work used experimental design techniques to develop proxy models for predicting oil recovery under water-flood and gas-flood conditions. The objective of the study is to develop a quantitative screening method that would allow for candidates to be evaluated and ranked for water flood or gas injection. The model was applied to some field cases and compared with published models and the well-known Welge Analysis method. The coefficient constants for the oil formation volume factor for water flooding and gas injection was 0.0139 and 0.0434 respectively. Similarly, the coefficient constants for water injection and gas injection for the generated proxy model was -2.34* 10-8 and -6.1 *10-5 respectively. The results show that the proxy models developed are quite robust and can be used for first pass screening of water and gas flood candidates.

The traditional method of using the coefficient of drag – Reynolds number relationship to predict cuttings settling velocity involves an implicit procedure that requires repeated, time-consuming and tedious iterations using Newtonian or mostly non-Newtonian correlations. Usually, these correlations are limited to certain fluid flow regimes. Besides, most of the explicit and direct cuttings settling velocity models that exist are based on the assumption that the cuttings are spherical particles. However, in the field, the cuttings are a mixture of various shapes and are hardly spherical, hence these models when applied to field conditions come off with huge errors. The objective of this work was to use a nature-inspired algorithm (artificial neural network - ANN) to develop a model for estimating cuttings settling velocity that would be robust and useful in the field that would take into account the shape of the cuttings. The data used for this work was obtained from research experiments in the literature. The model was then evaluated using four performance metrics namely: mean squared error (MSE), root mean square error (RMSE), sum of squares error (SSE) and goodness of fit (R2). It was found that the model's predictions obtained in this work agreed with experimental evidence. Furthermore, the developed model possesses the capacity to generalize across new input datasets and can be applied to particles of any shape, hence, defining the novelty of this research and bridging the gap between theory and practice. When compared with state-of-the-art models, the developed models show a high degree of robustness, as the ANN model performed reasonably well with an MSE of 7.5 × 10−4, an R2 of 0.978, RMSE of 0.0274 and SSE of 0.25. To generalize the results across new input datasets, the developed model was cross-validated with new data that was not part of the training process. It was found that the ANN model had an MSE value 0.00807, RMSE of 0.0898, MAE of 0.065, SSE of 2.74 and MAPE of 0.675%. To ensure the replicability of the ANN model, the weights and biases for the inputs, hidden and output layers are presented in this work unlike other artificial intelligence-based models in the literature. The range of application for the developed ANN model is 0.0001

The instability of crude oil prices at the international market which results in revenue drop to oil and gas operators, the high cost of drilling multiple injection wells and installing gas reinjection systems in a bid to improve recovery of crude oil, have been of great concern to the Petroleum Industry. The Economic viability of Gas Reinjection for Enhanced Oil Recovery (EOR) (as against the gas flaring operation) was analyzed with 7 wells located onshore, in the Niger Delta region of Nigeria. The production history and reservoir data were gathered with which the cost analyses were conducted. Two scenarios involving seven production wells were evaluated. The first was converting two of the production wells to gas injection wells and producing from the remaining 5 production wells (IN2PROD5) and the other was injecting gas in two newly drilled injection wells and producing from the seven production wells (INJ2PROD7). It was shown that (INJ2PROD5) is a preferred option in extending the productive life of an otherwise depleted and uneconomic oilfield, having higher Net Present Value (NPV), Profitability Index (PI) and Internal Rate of Return (IRR) of -$53MM, 0.93 and 27.40% while the INJ2PROD7 had $161MM, 1.39 and 37.75% at discounted rate of 30% respectively. After subjecting the expected net revenues under various crude oil price sensitivity market vagaries, INJ2PROD5 will stand the test of time as it is less expensive and yielded a higher gross profit which is the major factor in any investment decision making.

Aims: The variations in production performances of the Black oil and compositional simulation models can be evaluated by simulating oil formation volume factor (Bo), gas formation volume factor (Bg), gas-oil ratio (Rs) and volatilized oil-gas ratio (Rv). The accuracy of these two models could be assessed. Methodology: To achieve this objective some basic parameters were keyed into matrix laboratory (MATLAB) using the symbolic mathematical toolbox to obtain accurate Pressure Volume Temperature (PVT) properties which were used in a production and systems analysis software to generate the production performance and hydrocarbon recovery estimation. Standard black oil PVT properties for a gas condensate reservoir was simulated by performing a series of flash calculations based on compositional modeling of the gas condensate fluid at the prescribed conditions through a constant volume depletion (CVD) path. These series of calculations will be carried out using the symbolic math toolbox. PVT property values obtained from both compositional modeling and black oil PVT prediction algorithm are incorporated to determine the production performance of each method for comparison. Results: The absolute open flow for the black oil PVT algorithm and the compositional model for the Rs value of 500 SCF/STB and Rs value of 720SCF/STB were 130,461 stb/d and 146,028 stb/d respectively showing a 10.66% incremental flow rate. Conclusion: In analyzing PVT properties for complex systems such as gas condensate reservoirs, the use of compositional modeling should be practiced. This will ensure accurate prediction of the reservoir fluid properties.

The elimination of residual free water and Basic Sediments (BS&W) after field demulsification process and characterization is being investigated with a diluent, to enhance field treatment for quality assurance and crude oil custody transfer. The American Standard for Testing Materials (ASTM) D 4007 is used as separation technique for three field emulsion samples from two Niger Delta basin oil facilities. After an initial bottle test, free water content in crude oil samples on arrival were 0.65%, 0.70% and 0.55% for samples A, B and C respectively. Tests and analysis were carried out at room temperature of 28°C and a water-bath temperature at 60°C. Maximum water separation efficiency of 91% was achieved at diluent and emulsion concentration ratio of 1:9 in first 60 minutes to 720 minutes. BS&W reduced from an average of 0.6% to 0.25%. Emulsion separation index (ESI) provided emulsion stability measurement of respective samples with a contrast between static-laboratory and field-dynamic conditions. From the study, sample B has API of 39 and ESI=40 while recording greater separation than in A and C crude oil samples. Hence, separation efficiency increased with the amount of xylene added and free water percentages reduced in top dry oil with significant changes in BS&W.

Carbon adsorbents derived from biomass (agricultural and household residues) have been widely used in the sequestration of hazardous substances from the environment due to their distinctive qualities of large internal surface area, mechanical integrity, and regeneration. The need for carbon adsorbents for sequestration of dyes, heavy metals, and crude oil components has increased because of environmental concerns. This has led to studies of carbon adsorbents derived from agricultural and household biomass residues. These adsorbents have been used to remove pollutants. Although numerous reviews have been published before, analogy of results obtained using different adsorbents is hard due to dissimilarities in research data. Against this backdrop, the purpose of the research survey was to review the contemporary publications regarding the production of activated carbon from biomass sources highlighting specifically its utilization in removing toxic wastes from water solution such as oil spill, dyes, and sundry hazardous substances. Also the work focuses on the methods for the restoration of the spent adsorbents and their end use.

In this paper, an artificial neural network model was developed to predict the downhole density of oil-based muds under high-temperature, high-pressure conditions. Six performance metrics, namely goodness of fit (R2), mean square error (MSE), mean absolute error (MAE), mean absolute percentage error (MAPE), sum of squares error (SSE) and root mean square error (RMSE), were used to assess the performance of the developed model. From the results, the model had an overall MSE of 0.000477 with an MAE of 0.017 and an R2 of 0.9999, MAPE of 0.127, RMSE of 0.022 and SSE of 0.056. All the model predictions were in excellent agreement with the measured results. Consequently, in assessing the generalization capability of the developed model for the oil-based mud, a new set of data that was not part of the training process of the model comprising 34 data points was used. In this regard, the model was able to predict 99% of the unfamiliar data with an MSE of 0.0159, MAE of 0.101, RMSE of 0.126, SSE of 0.54 and a MAPE of 0.7. In comparison with existing models, the ANN model developed in this study performed better. The sensitivity analysis performed shows that the initial mud density has the greatest impact on the final mud density downhole. This unique modelling technique and the model it evolved represents a huge step in the trajectory of achieving full automation of downhole mud density estimation. Furthermore, this method eliminates the need for surface measurement equipment, while at the same time, representing more accurately the downhole mud density at any given pressure and temperature.

The study investigates the sorption of cadmium (Cd) and lead (Pb) by Nsukka urban soils, a Nigeria soil classified as an ultisol soil of tropics. Laboratory batch technique was utilized to investigate the effect of pH, temperature, contact time, and concentration on the adsorption process. Results showed that adsorption efficiency of the soils for Cd2+ and Pb2+ increased with increase in pH, temperature, and contact time but decreased with increase in concentration. The data from adsorption study was fitted to the Langmuir, Freundlich and Temkin adsorption isotherms, and results revealed that Langmuir isotherm fitted most satisfactorily. On the basis of the obtained maximum adsorption capacity (qmax) from the Langmuir model, the affinity of Cd and Pb for the studied soil was Pb2+ > Cd2+. Pseudo-second order (r2 ≥ 0.995-0.999) best described the kinetics of the sorption process for the metal ions in the soil.

The adsorptive removal of total dissolved solids by activated coal using response surface methodology was investigated. A four-variable central composite experimental design was applied to correlate the adsorption variables (effluent pH, adsorbent dosage, contact time, and adsorption temperature). The adsorption variables were optimized based on the removal of total dissolved solids from fibre cement industry effluent. Three-dimensional surface plots were generated to estimate the effect of the combinations of the independent variables on the adsorption efficiency. The results of the model validation gave experimental yield 96.2%, predicted yield 96.5% obtained at effluent pH 6.27, adsorbent dosage 27.60 mg L−1, contact time 48.00 min, and adsorption temperature of 31.00 °C. The good agreement found between observed and predicted values supports the suitability of the applied model to predict the adsorption treatment.

N -(2-chloroethyl)morpholine-4-carboxamide (NCMC), N -(2-chloroethyl)tiomorpholine-4-carboxamide (NCTC) and N , N -bis(2-chloroethyl)piperazine-1,4-dicarboxamide (NCPD) were studied as corrosion inhibitors for mild steel using atomic absorption spectroscopy (AAS) and gravimetry and thermometry. Results obtained from the three techniques are similar and reveal that the compounds inhibit mild steel corrosion. The inhibition efficiencies increased from 35.6% to 74.9% (NCMC), 44.5% to 82.4% (NCPD) and 52.6% to 90.1% (NCTC) at 30 °C when the inhibitor concentrations increased from 10 μM to 50 μM. The maximum inhibition efficiency values (at 50 μM) decreased to 46.6%, 58.1% and 61.2% for NCMC, NCPD and NCTC respectively, when the temperature was raised to 50 °C. The decrease in inhibition efficiency with increase in temperature suggested predominant physisorption mechanism in metal/inhibitor interactions. The formation of protective films of NCMC, NCPD and NCTC molecules on mild steel surface were confirmed by FTIR and XRD. The order of inhibitive strengths of the molecules is NCTC > NCPD > NCMC. Quantum chemical calculations revealed the prospective sites through which the molecules can interact with mild steel surface and some quantum chemically derived parameters were used to corroborate experimental.

Removal of arsenic(III) from aqueous solution has been studied using activated carbon produced from Dialium guineense seed shell by impregnation of carbonized sample with zinc chloride and thermal activation. The zinc chloride activated sample was selected because it produced the highest iodine number, mg/g (962.52) compared to the raw sample (601.57), phosphoric acid and nitric acid impregnated samples (802.10, 868.95). Proximate analysis of raw D. guineense seed shell revealed low ash content of 1.70% and moderate fixed carbon of 32.97%. The prepared adsorbent was characterized using Brunaeur–Emmett–Teller surface area, SEM and FTIR analyses. The surface area of the zinc chloride activated adsorbent was 533.94 m2/g and its micropore volume 0.475 cm3/g, with a porous structure that is well organized. Batch adsorption experiments were done by changing the following parameters: adsorbent dose, pH, contact time, initial metal ion concentration and temperature. Adsorption increased as each parameter was varied but decreased with increase in initial arsenic(III) concentration. The Freundlich model presented better fit with R2 of 0.998 compared to the Freundlich isotherm (0.991) and Tempkin isotherm (0.984). The positive value of ∆H° 51.68 kJ/mol showed the endothermic nature of adsorption. The study demonstrated the potential of D. guineense seed shell as low cost adsorbent for removing arsenic(III) from polluted water.

When drilling with water based muds (WBM), significant fluid loss volumes from the mud into the formation can have adverse effects not just on the mud and its properties but also on the stability of the wellbore. Prevention of mud filter loss is one way of assessing the performance of a drilling mud. However, evaluation of the effectiveness or otherwise of a fluid loss control additive can be made by characterizing the mud cake formed. Interestingly, the mud cake characterization is one area that has been somewhat neglected in drilling fluid formulation with agro waste materials. Two cellulosic materials - rice husk and saw dust were chosen for the experimental study. The specie of the rice husk used was the African rice (Oryza glaberrima) while the dust from the saw milling of Oxystigma manni was utilized for this study. To ensure result acceptability, the rice husk and saw dust were ground and the resulting products were sieved to 1.25 × 10−4 m. The filtration characteristics of the formulated mud samples were tested using the American Petroleum Institute (API) filter press and in accordance to the API recommended practice for field testing WBMs. From the filter loss tests, it was observed that the ground rice husk prevented filter loss by an average of 77% compared to ground saw dust filtration control of 63%. In addition, it was observed that at higher concentrations, ground saw dust and rice husk prevented fluid loss to the minimum acceptable API standard. For the filter cake thickness measured in millimetres, ground rice husk exhibited thicker mud cakes when compared with the saw dust by an average amount of 14%. For the mud cake characteristics, the rice husk mud exhibited smooth and slippery cakes while the saw dust mud exhibited rough texture, sticky and firm cakes.