Journal Articles

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Journal Articles (Chemical Engineering)

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Open Access
Adaptive neuro-fuzzy inference system-genetic algorithm vs . response surface methodology: a case of ferric sulfate-catalyzed esterification of palm kernel oil
( Process Safety and Environmental Protection, 2015-07) Ishola, Niyi B.; Adeyemi, Omowumi O.; Adesina, Ayo Joshua; Odude, Victoria.O
Ferric sulfate-catalyzed esterification process for palm kernel oil (PKO), which had an initial acid value (AV) of 22 ± 0.1 mg KOH/g oil, was modeled using response surface methodology (RSM) and adaptive neuro fuzzy inference system (ANFIS). The process parameters investigated in the AV reduction of the oil were methanol-to-oil ratio (2:1–3:1), catalyst loading (6–10 w/v) and reaction time (15–25 min) using Box Behnken design of RSM. The developed ANFIS and RSM models were both subjected to various statistical evaluation and they both showed high degree of accuracy based on the high values of coefficient of determination (R²) of 0.9662 and 0.9039 for ANFIS and RSM, respectively and low values of mean absolute error of prediction (MAE) 0.0506 and 0.1506, and average absolute deviation (AAD) of 2.3665 and 7.1179 for ANFIS and RSM, respectively. To minimize the AV for the PKO, the process parameters investigated were optimized using RSM and ANFIS coupled with genetic algorithm (GA). Optimum values of methanol-to-oil ratio of 2.96:1, catalyst amount of 6 w/v and reaction time of 15 min with a corresponding AV of 1.05 mg KOH/g oil (95.2% AV reduction) were established using ANFIS-GA, while the values obtained using RSM were methanol-to-oil ratio of 2:1, catalyst amount of 6 w/v and reaction time of 25 min with a corresponding AV of 1.54 mg KOH/g oil (93.0% AV reduction). Based on the statistical indicators employed for this work, ANFIS was a better prediction tool than RSM while GA outperformed RSM in the optimization of the esterification process. Ferric sulfate proved to be a good catalyst for PKO esterification
Open Access
Effect of Emulsification Process Conditions on the Properties of Water-in-Bitumen Emulsion
( Journal of the Japanese Association for Petroleum Technology, 2017-01) Alade, Lekan; Yuichi, Sugai; Sasaki, Kyuro; Ademodi, Bayo
Steam or hot water injection into the bitumen reservoir leads to the formation of water-in-bitumen emulsions which exhibit higher viscosity compared to the original bitumen; and thereby affects production flow. The understanding of the effect of formation process conditions on the nature of this emulsion could assist in production improvement, design and simulation of post-production separation system. In this work, water was dispersed in bitumen phase at different temperatures (50-180°C) and mixing speeds (11.7-23.3s⁻¹). Emulsification properties such as percentage emulsification (extent of water dispersion into the bitumen), and the particle size of emulsion were analyzed to evaluate the effects of the process conditions. Ultimately, correlations have been presented to predict emulsion properties from the process conditions
Open Access
Environmental Working Conditions, Lung Function and Total Serum Bile Acids of Spray Painters Exposed to Organic Solvents in Ile-Ife, Nigeria
(JH&P, 2017-03) Temitope O, Ojo; A.J, Adesanmi; Onayade, Adedeji A; Akinyemi, Patrick Ayodeji
Nigeria has a growing spray painting industry, however, the burden of occupational health problems related to organic solvent exposure among spray painters in Nigeria is under-studied. This study aimed to assess workshop characteristics and ambient concentration of total volatile organic compounds (VOCs) in spray painting workshops and to compare lung function status and total serum bile acid levels of spray painters and controls. A cross-sectional study design was employed to survey 120 spray painters and 120 controls (electronic technicians). A semi-structured questionnaire was used to obtain data on socio-demographics characteristics of the respondents. Weight, height and lung function of respondents were measured. In addition, a checklist was used to survey the spray painting workshops. Total VOC levels were determined in 37 spray painting and 31 electronic workshops. Data were analyzed using Statistical Program for the Social Sciences (SPSS) version 20 and a p-value of <0.05 was considered to be statistically significant. Windows were present in only 5 (13.5%) spray painting workshops and 23 (62%) workshops had a retractable tarpaulin at the entrance. Only 9 (24%) workshops had changing rooms, while fire extinguishers and first aid kits were not present in any of the surveyed workshops. A respirator with filter was sighted in only 1 (3%) workshop. The 8-hour time weighted average concentration of total VOCs in spray painting workshops was 13.4 ppm, which is above the national permissible exposure limits of 1.9 ppm. Forced vital capacity (FVC) percent predicted was significantly lower in spray painters (93.9 ±10.8%) than controls (96.7± 8.2%) (t = -2.326, df=238 p< 0.001). In addition, forced expiratory volume in the first second (FEV1) percent predicted was lower in spray painters (94.6±12.2%) than controls (100.3±9.1%) (t=-4.058, df=238, p=0.002). FEV1/FVC% was significantly lower among spray painters (85.48±8.70%) compared with controls (87.88±6.22%) (t=-2.861 df=238, p= 0.005). Total serum bile acids was significantly elevated in painters (8.71±3.39 mmol/l) compared to controls (4.67 ±2.15 mmol/l) (t=10.358, df=213, p<0.05). Spray painters in the present study conduct their activities in hazardous work settings. More needs to be done concerning workplace regulation and enforcements to ensure that spray painters comply with minimum standards of occupational safety, workplace hygiene and sanitation. Obtained Ethical approval was granted by the Health Research and Ethics Committee of the Institute of Public Health, Obafemi Awolowo University.The authors declare no competing financial interests.
Open Access
Estimation of sulphur dioxide emission from consumption of premium motor spirit and automotive gas oil in Nigeria
(Cogent Environmental Science, 2017-05-17) Okedere, O.B.; Ajala, Olawale E.; Sonibare, Jacob; Adesina, Olusola
Abstract: This paper estimated the annual levels of sulphur dioxide (SO2 ) from consumption of premium motor spirit (PMS) and automotive gas oil (AGO) across the States and Regions of Nigeria. This was with a view to estimating the per capita and land distributions of emissions. Annual fuel consumption, average fuel sulphur contents and emission factors were combined to estimate the annual levels of SO2 . Per capita and land distributions of emissions were then established using population and land area, respectively. Results showed that Lagos and Ogun States had the maximum SO2 emissions from consumption of PMS and AGO, respectively, in 2012. Between 2001 and 2014; most of the SO2 emissions from consumption of PMS and AGO came from the South-western and South-southern regions of the country, respectively. Based on projected future fuel consumption, annual SO2 emissions from utilization of PMS and AGO are projected to further increase over their 2014 estimates. Interim measure suggested for mitigation of SO2 emission is the importation of refined products with highly reduced sulphur contents. Medium to long-term measures include building of more refineries locally to make use of Nigeria’s crude oil which is generally low in sulphur content and a massive improvement in the country’s energy generation so as to lower the demand pressure on refined petroleum products.
Open Access
Ground level concentration of some air pollutants from Nigeria thermal power plants
(Taylor & Francis, 2016-08-12) A. J, Adesanmi; Bamidele Sunday, Fakinle; Jamiu Adetayo, Adeniran; Rafiu Olasunkanmi, Yusuf
Power sector in Nigeria is undergoing structural reforms aimed at improving and expanding the current generation capacity, using thermal power plants. Ground level concentrations of air pollutants emitted from natural gas-powered thermal power plants were estimated using the American Meteorological Society-Environmental Protection Agency Regulatory Model (AERMOD). The average 24-h ground level concentrations of CO, NOx, SO2, particulate matter (PM), and volatile organic compounds (VOCs) were 31.88–72.79; 61.33–104; 0.61–3.91; 0.21–1.52; and 0.19–1.09 µg/m3, respectively. There is need for continuous monitoring of ground level concentration of pollutants around the thermal power plants to guarantee the safety of the environment in the host communities
Open Access
Optimization of Bauhinia monandra seed oil extraction via artificial neural network and response surface methodology: A potential biofuel candidate
(Elsevier B.V., 2015-01-30) Aramide M, Akintunde; Sheriff Olalekan, Ajala; Eriola, Betiku
The influence of sample weight, time, and solvent type and their reciprocal interactions on Bauhinia monandra seed oil (BMSO) yield using artificial neural network (ANN) and response surface methodology (RSM) was investigated. Also, the BMSO obtained was characterized to determine its aptness for oleochemical industry. Numerically predicted optimum values for the extraction process using RSM model were found to be the same for the developed ANN model. The optimum values were sample weight of 60 g, time of 100 min and petroleum ether with a corresponding BMSO yield of 14.8 wt%. Performance evaluation of the models by multiple coefficient of correlation (R), coefficient of determination (R2) and absolute average deviation (AAD) showed that the ANN model was marginally better (R = 0.9995, R2 = 0.9991, AAD = 0.27%) than the RSM model (R = 0.9993, R2 = 0.9986, AAD = 0.49%) in predicting BMSO yield. Physicochemical properties of the BMSO such as acid value (7.56 mg KOH/g), indicated that it is non-edible and the fatty acids profile showed that the oil was highly unsaturated (87.9%), which makes it a potential candidate for biodiesel production.
Open Access
Periodic characterization of alkylnaphthalenes in stack gas and ambient air around a medical waste incinerator
(Springer-Verlag GmbH Germany, 2017) Adesina, Olusola Adedayo; Sonibare, Jacob Ademola; Diagboya, Paul N.; Adejuwon, Adesuji; Famubode, Temitope; Bello, Josiah O.
Due to the subtle occurrence of environmental polycyclic aromatic hydrocarbon (PAHs) pollution from incinerators, it is seldom considered a significant source of PAH pollution. However, considering the recent build-up of toxics in urban air, this may be a serious concern around the incinerator vicinity due to the potential consequences of PAHs on human health.Hence, this study determined 11 alkyl-naphthalene contributions from a hospital waste incinerator (HWI_0) into ambient air receptor points (HWI_1 to HWI_5) for a 1-year period: June 2014–May 2015. The HWI_0 and ambient gases were sampled using filter-sorbent sampling system and polyurethane foam (PUF) passive samplers, respectively, and all alkyl-naphthalenes were determined using GC-MS. Results showed that the source concentrations were in the range of 0–14.0 ng/m3 and generally higher than the receptor points. The receptor point concentration trends were mainly HWI_1 > HWI_2 ≥ HWI_3 ≥ HWI_5 ≥ HWI_4. Multivariate receptor model analysis suggested high correlations between source and the receptor points though there might be some significant contributions from other emission sources. The average monthly concentrations (Σalkyl-naphthalene) at HWI_0 and the receptors HWI_1, HWI_2, HWI_3, HWI_4 andHWI_5were 67.4 ± 24.3, 57.9 ± 20.1, 42.8 ± 16.9, 39.7 ± 12.2, 36.5 ± 22.2 and 37.8 ± 15.4 ng/m3, respectively. Though these concentrations were lower than the estimated minimal risk level (MRL) for chronic inhalation exposure to naphthalene and its derivatives 0.003 mg/m3, continuous exposure to these pollutants might result in chronic effects. Finally, this study may be used to evaluate the environmental contribution of alkyl-naphthalenes from typical medical waste incinerator in Nigeria.
Open Access
Personal exposures to particulate matter in various modes of transport in Lagos city, Nigeria
(Cogent Enviromental Science, 2016-11-17) Odekanle, Ebenezer Leke; Fakinle, Bamidele Sunday; Akeredolu, F.A; Sonibare, Jacob
Urban air pollution continues to be a major problem in Nigerian cities. Most studies of air pollution in Nigeria have concentrated on the background air quality and its eects on people outside vehicles. However, it has been suggested that in-vehicle pollution is often worse than pollution outside the vehicle. This study focuses on personal exposures to PM10 and PM2.5 in various modes of transportation in Lagos city. Six roadways which are representative of commercial, industrial, and residential areas of the city were selected. Measurements were made inside four major modes of transportation in the city: cars, buses, Bus Rapid Transit (BRT), and walking for PM10 and PM2.5. Measurements were done for each mode twice a day (morning and afternoon) for 12days. The highest average PM10 and PM2.5 concentra- tions were measured for pedestrian (476.35 and 216.60μg/m3, respectively) dur- ing rush hours. The result showed that pedestrians were found to be exposed to the highest average PM10 and PM2.5 concentrations, while commuters in cars, BRT and buses were exposed to respective decreasing concentrations of PM10. Similarly, commuters in BRT were exposed to the lowest concentrations of PM2.5 regardless of time of day. The results obtained were much higher than the results for London but comparable to Mexico city and Taiwan’s results. This study has provided information that can help commuters to choose appropriate travel behavior that can minimize their exposure to particulate matter
Open Access
Total Sulfur Levels in Refined Petroleum Products of Southwestern Nigeria Using UV/VIS Spectrophotometer
(Taylor & Francis, 2014-12-08) Olatunji, Samuel; Adeniran, Jamiu Adetayo; Fakinle, Bamidele Sunday; Sonibare, Jacob
This study employed turbidimetric method using a UV/VIS spectrophotometer to determine the total sulfur levels of refined petroleum products in Southwestern Nigeria. The sulfur concentrations in the analyzed fuel samples were 0.0019–0.0178 wt% and 0.027–0.169 wt% for gasoline and diesel, respectively. Sulfur levels in the selected samples were below the Nigerian standard for gasoline and diesel while 89.9% of the samples exceeded the U.S. Environmental Protection Agency standard. The turbidimetric method showed better performance than the gravimetric method. The results gave insight into the adverse environmental impact the nonuniform quality of fuels imported could pose to the country

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