Department of 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
Adsorptive Separation of Benzene -Toluene-Xylene (BTX) from Fluid Catalytic Cracking Unit Effluent.
(Obafemi Awolowo University, 1986) Ozemoyah, P. O.; Sanni, S. A.; Fasesan, S. O.
The separation of mixtures of industrial benzene, toluene and mixed xylenes was carried out using the pulse test technique. Three adsorbent types - silica gel, fuller's earth, and a combination of the two were used. Three groups of solvents - alkylhalides, alcohols, and ketones - were employed as the desorbents. Liquid effluent from Fluid Catalytic Cracking (FCC) unit of the Warri Refinery was treated in a manner similar to that for the industrial BTX mixtures. Diethyl ether and mixed xylenes were, in addition to the ones mentioned above, used as desorbents. The silica gel-xylene combination of adsorbent-desorbent gave pure aromatic hydrocarbon from the FCC gasoline, but could not wholly separate the BTX. In order to enhance good BTX separation the FCC gasoline was fractionated. The FCC gasoline was fractionated into four cuts. The aromatic content of the tour tractions and that of the original FCC gasoline were determined using the Fluorescent Indicator Adsorption (FIA) equipment. The only fraction containing all the required components of benzene, toluene and xylene was subjected to adsorption/desorption process in a column using silica gel as adsorbent and trichloromethane as desorbent. BTX of about 90 percent purity was obtained. Fixed-bed adsorption columns were then designed for the process using silica gel as the packing material. Columns of 6m high and 1.3m diameter were obtained. The gel inventory for each column was about 6,000kg and the total pressure drop expected for the designed domed end column is less than 4500 N/m2. The gel capacity for the BTX at its concentration in the BTX "heart cut" (80-120°C) was found to be about 0.185 ml/g in n-hexane.
Open Access
Analysis of Microbial Growth and Product Formation Data Using Modified Pirt's Model.
(Obafemi Awolowo University, 1985) Agho, Godfrey Nosakhare; Layokun, S. K.
The 'true' biomass and product energetic yield coefficients and the maintenance coefficient for different microorganisms have been determined by analysing data on microbial growth, with and without product formation, using modified Pint's model. The data of kappeli and Fiechter for the aerobic growth of Trichosporun cutaneum on glucose in continuous culture and those of Duvnjak et al for the anaerobic growth of various strains of Saccharomyces and Kluyveromyces on Jerusalem artichokes in batch culture were analysed. Material and energy balances were carried out and these with identified regularities were used to establish the consistency of the data and also used to identify probable sources of measurement errors and outlier data points. The estimates of the yield and maintenance coefficients, obtained using the modified Pirt's model, are presented improved estimates are obtained using covariate adjustment method. The values of the true biomass yield and the maintenance coefficients obtained from the analysis of the data of T. cutaneum are 0.668 and 0.007 respectively. These values compare favourably with those reported for candida utilis which is used for biomass (single cell protein) production. Analysis of the growth studies on Jerusalem artichokes show that the microorganism, K. fragilis 105, may be the best for ethanol production on this substrate. The method used in this work will have applications in the selection of new strains of microorganisms.
Open Access
Artificial Neural Network Modeling of Viscosity and Wax Deposition Potential of Nigerian Crude Oil and Gas Condensate
(2015-05-05) Oladiipo, Abiodun Koyumu
Artificial Neural Network (ANN) based models were developed for predicting viscosity and wax deposition potentials of petroleum reservoir fluids as a preliminary measure to address the problem of loss of production associated with wax deposition. Several ANN architectures were trained using supervised paradigms for viscosity modelling and unsupervised paradigms for wax deposition potentials. Input to the model for viscosity prediction was temperature and pressure data of the reservoir well, while wax deposition potential model regime. For viscosity prediction, Levenberg Marquardt (LM), Bayesian Regularization (BR), Brodyen , Fletcher, Goldfarb and Shano (BFG), Powelle-Beale Conjugate Gradient (CGB), Generalized Regression Neural Network (GRNN), Resilient Back-Propagation (RP), Scaled Conjugate Gradient (SCG), and Adaptive Gradient Descent (GDX) algorithms were used in two layers and three layers architectures with tan-sigmoid transfer function in hidden layer and linear transfer function at the output layer. Competitive layer and Probabilities neural networks algorithm were used in the wax deposition prediction model. Five Nigeria crude oil and gas condensate reservoir data were used to validate the models. The correlation coefficient of viscosity algorithm are: LM (99.84%), CBG (99.76%), SCG (99.72%), BFG (99.75%), GDX (99.71%), GRNN (98.27%), BR (41.10%). The two layer networks trained with LM algorithm for viscosity with twenty six neurons in the hidden layer gave the best performance. The viscosity model developed with ANN has correlation coefficient of 99 81%, while classical regression techniques (CRT), developed had correlation coefficient of 95%, when both techniques were validated with blind data set. ANN competitive wax deposition model developed in this work excellently identified crude oil and gas condensate potential to deposit wax in upstream and down stream facilities compared to CRT based mathematical model, when validated with Nigerian crude oil and Gas condensate. The inherent problems of pipeline blockage by wax deposits would be minimized by the application of the predicting models during well development stage prior to production.
Open Access
Cancer in our Society
(Obafemi Awolowo University Press, 1983-11-15) Olusi, S.O
In Nigeria, cancer statistics like any other statistics may be rather nebulous. Just as there are no accurate statistical data on our population figure, there is very little or accurate information on the incidence of cancer in the Nigerian society. However, we know that cancer ranks behind the major causes of death: malnutrition, malaria, infections and infestations and accidents.
Open Access
A Catalogue of Alternatives
(Obafemi Awolowo University Press, 1979-06-12) Sanni, S.A
The effects of Chemical Engineering are less obvious but are just as all-pervasive and growing infiltration of the products of engineering and technology into every home, and to the fact that our lives are more and more conditioned by engineering and technology. This is particularly true of the so-called Less Developed Countries. Consequently, indiscriminate pursuit of advanced technologies by these countries without adequate attention to the human and environmental problems are giving rise to a number of social and psychological maladies, the gravities of which are evident in our craze for imported products.
Open Access
Citric Acid Production from Cassava Hydrolysates and Molasses Using Aspergillus Niger
(2015-06-18) Alao, Mofoluwake Moronfade
This work investigated the potential of cassava and molasses as feedstocks for the production of citric acid using indigenous Aspergillus niger. This was with the view to developing indigenous biotechnological process for its production. Cassava starch was extracted from freshly harvested tubers and hydrolyzed into glucose and maltose-rich syrups using enzyme hydrolysis method, while molasses was pretreated to serve as sucrose source. The hydrolysates and molasses were used as feedstocks for the cultivation of A. niger. Fermentation was carried out under shake flask culture using the gyratory incubator shaker at a temperature of 30 °C and agitation rate of 100 rpm for ten days. Surface culture fermentation of the hydrolysates and molasses was also carried out using ten sets of 250 ml Erlenmeyer flasks for ten days. The initial pH of 4.0 and 3.0 was employed and for optimum citric acid production, different concentrations (glucose-rich syrup: 140, 180 and 235 g/L; maltose-rich syrup: 140 and 330 g/L and sucrose based molasses: 140 and 180 g/L) were used. Samples were withdrawn at 24 hour intervals and analyzed for citric acid. biomass and reducing sugars. The variation of pH profile of the cultures with time was also monitored. The results showed that the glucose-rich syrup obtained from the hydrolysis of cassava starch was able to support the growth of the microorganism used in this study. Of all the three concentrations investigated, glucose-rich syrup of 180 g/L gave the highest citric acid accumulation (17.6 g/L) on the eight day of fermentation followed by the glucose-rich syrup of 235 g/L with 11.3 g/L of citric acid accumulation on the eighth day of fermentation and lastly, glucose-rich syrup of 140 g/L with 10.1 g/L citric acid production on the fourth day of fermentation. Highest biomass concentrations obtained were 37.1, 36.1, and 32.7 g/L with corresponding glucose-rich syrup of 180, 235 and 140 g/L, respectively. For maltose-rich syrup, the highest citric acid accumulation (2.61 g/L) was obtained from 140 g/L on the third day of shake fermentation which was low when compared with 6.9 g/L obtained from 140 g/L on the seventh day of surface fermentation. These values were lower than any of results obtained for the various concentrations of glucose-rich syrup investigated in this work. The highest production of biomass observed was 29.6 g/L on the tenth day of surface fermentation. It was observed that 330 g/L maltose-rich syrup was not favourable to citric acid and biomass production; the highest accumulation of citric acid recorded on the eighth day of shake fermentation was 2.1 g/L while highest biomass production obtained was 2.6 g/L on the tenth day of fermentation. Investigations on sucrose based molasses showed that 140 g/L gave highest citric acid of 6.5 g/L on the sixth day and 180 g/L gave 11.6 g/L on the tenth day of fermentation under surface culture. The best biomass concentration throughout this work (46.1 g/L) was obtained from 180 g/L sucrose based molasses on the tenth day. The study concluded that glucose-rich syrup obtained from cassava starch hydrolysates favoured the accumulation of citric acid than maltose-rich syrup and sucrose from molasses. In addition, surface culture favoured the production of citric acid than shake culture.
Open Access
Development of an Optimal Additive Package for Re-refined Lubricating Oils.
(Obafemi Awolowo University, 1986) Mensah-Brown, Henry; Oshinowo, Toks; Ademodi, Bayonile
The re-refining of used SAE 20W- 50 lubricating oils from automotive (car) gasoline engines and the development of an additive package for the re-refined oil has been investigated. Vacuum distillation preceded by caustic treatment of the used oil produced about 65% (w/w) of SAE 30 grade base tube stock. Response Surface Methodology (RSM) was successfully utilized in the optimization of an additive package consisting of an oxidation/corrosion inhibitor, detergent and dispersant additives as independent variables. Neutralization number, corrosion and sludge deposition were the responses measured. An optimal additive package of 0.988% (v/v) oxidation/ corrosion inhibitor 1.325% (v/v) detergent additive and 3.0% (v/v) dispersant additive was found for the SAE 40 grade lubricating oil obtained from a blend of the re-refined oil and bright stock in the ratio 3:1.
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
Improving Binary Distillation Column Design and Operation Using Exergy Analysis
(2015-05-14) Osuolale, Funmilayo Nihinlola
This study developed methodologies that would improve the design and operation of distillation column by reducing the irreversibility within the column and improving the column efficiency. This was with a view to minimize the consumption of energy in distillation processes. Two binary systems benzene-toluene and methanol-water were considered for this research. The performance parameters for these systems were obtained from McCabe Thiele and 'Ponchon-Savarit methods of designing distillation columns in chemical engineering. The systems were simulated using process simulator software HYSYS with capabilities for generating the thermodynamic and physical data of the components. Different variations were made for the design and simulation of the column. Exergy analysis of the data was carried out using a program developed and written in C++ language. The enthalpy versus exergy factor graph and the temperature versus exergy graph were used to identify the best operating and design variables. Also the total cost (energy and capital) was used to identify the best design variables. Efficiencies and irreversibility calculations were made for each of the design and simulation variation. The results showed that the optimum operating feed temperature for the systems were 95°C and 79°C for benzene-toluene and methanol-water systems respectively. Feed rate of the systems were 260kmol/hr and 84.4kmol/hr for benzene-toluene and methanol water systems respectively and column pressure for the systems was l atm as against feed rate of 350kmol/hr for benzene-toluene system and feed temperature of 53°C for methanol-water system. Also optimum reflux ratio for the systems was 2 for benzenexv toluene and 1.5 for methanol-water from the thermodynamic diagrams as well as from the cost analysis method. It can be concluded that the developed methodologies could be used to know the optimum operating conditions for a distillation column and the methodologies were found to be useful tools in the design and operation of energy efficient distillation column.
Open Access
Modeling of an Herbivorous Digestive System as a 3-Continuous Stirred Tank Reactor (CSTR) -1-Plug Flow Reactor (Per) Arrangement with Particular Reference to Hippopotamus Amphibious
(2015-04-16) Awolu, Olugbenga Olufemi
Hippopotamus Amphibious has three stomach compartments together with small and large intestines all required in digesting lignocellulosics. It is desirable to model the performance of such a natural (in - vivo) system with the view to designing a physical (in-vitro) system for efficient digestion of lignocellulosics. Each stomach compartment in Hippopotamus Amphibious was modeled as a continuously stirred Tank Reactor (CSTR) and the small and large intestines as Plug Flow Reactor (PFR) arrangement in series in order to determine the performance of the digestive system. Monod Kinetics and Michaelis-Menten equations were used to develop the design equation (-rAM = f(X)) used for the sizing of the reactor, where -rAM is the rate of disappearance of substrate from the reactor(s) and X is the conversion. The equation was at steady state. The solutions from the design equation above are obtained graphically using Levenspiel plot and numerically, using Simpson's Rule to solve the Integrals, in order to determine the efficiency of each reactor at converting the substrates (lignocellulosics) into the final products. The result showed that 3CSTR – 1PFR arrangement in series has reactor volume of 0.5863m3, while ICSTR — 1PFR has 0.6120m3. The model of the whole system as 1PFR has reactor volume of 0.6030m3, The 3CSTR —1PFR which has the lowest value of 0.5863m3 is the best reactor arrangement to achieve efficient digestion of lignocellulosics. It could be concluded that, the Hippopotamus Amphibious digestive system is best modeled, in –vitro as a 3CSTR – 1PFR arrangement in series.
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
The Potentials of Biochemical Engineering in Industrial Development
(Obafemi Awolowo University Press, 1998-08-11) Layokun, S. K.
The exploitation of micro-organisms is at the heart of biochemical engineering practice. The new science of molecular biology has produced a remarkable outpouring of new ideas and powerful techniques. From this revolution has sprung, in particular, a new discipline, called genetic engineering which gives us the power to alter living organisms for important purposes in medicine, agriculture and industry. The resulting biotechniques span the range from the ancient art of fermentation principles (about 7,000 BC) to the new esoteric use of gene splicing and monoclonal antibodies.
Open Access
Recovery of Heavy Oil from Nigerian Tar Sands.
(Obafemi Awolowo University, 1985) Dawodu, Olukayode Fatai; Oshinowo; Ademodi
Solvent extraction of heavy oil from Nigerian tar sands has been investigated using toluene. Pulverization, followed by sieving of the tar sand resulted in spherical agglomeration of the tar sand particles. The agglomeration was found to beneficiate the tar sands in terms of increased percent oil content to the tune of and 13% for the rich and lean tar sands respectively. The effects of solid/liquid ratio, temperature and agitation on the extraction process were evaluated factorial experimental design. Extraction efficiency was found to increase with increasing agitation speed and cuss transfer driving force, expressed in terms of solid/ liquid ratio, but decreased with increasing temperature. Of the three variables, the solid/liquid ratio the greatest effect on extraction efficiency. The rate of oil extraction, expressed as extractibility showed a great dependence on agitation. Twelve and thirteen fold increases creases in extractibility were obtained at solid/liquid ratios of 1/20 and 1/5 respectively for 2.8 fold increase in agitation (250 r.p.m to 700 r.p.m). The asphaltenes content of the heavy oil extracted at 50C was about 12% lower than that of the heavy oil extracted at 25°C for extraction times below 10 minutes. The implication of this reduction in asphaltenes level could be very significant in terms of the cost of upgrading the heavy oil. Stage-wise extraction gave high extraction efficiency at a low solid/liquid ratio. An efficiency of about 99 was obtained at a total, solid/liquid ratio of 2/3 w/v (43wt% solid loading) and agitation speed of 430 r.p.m in a three stage extraction. From an analysis of the power consumed and time ±or extraction, it was found that 440 r.p.m, 26 minutes and 440 r.p.m, 18 minutes could be the most economical agitation and time levels of operation at solid/liquid ratio- of 1/5 and 1/20 respectively.
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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