Data from literature and a stoichiometric material balance model were employed to estimate associated emissions with flaring of sweet gas in Nigerian oil and gas companies. Emission factors were obtained using AP 42 formula. Results showed that thousands of tonnes, ranging from 6500 to 22,000 tonnes of natural gas were flared from 1997 to 2016. At flaring stack efficiencies of 97% and 98%, the associated emissions are: CH4, C2H6, C3H8, iC4H10, nC4H10, iC5H12, nC5H12, C6H14, C7H16, C8H18, C9H20, CO2, and N2 from unburnt natural gas and in addition to CO2, CO, N2, NO, NO2, H2O and H2 from incomplete combustion. At both flaring stack efficiencies, the amount of emissions from unburnt condition ranged from1,608 tonnes N2 to 9,146 tonnes CO2 all higher than any emission standards in the world, while the amounts of emissions from incomplete combustion ranged from 467,964 tonnes for CO2 the lowest to 2,476,011 tonnes for N2 the highest all higher than any emission standards in the globe. Emission factors of emissions from unburnt natural gas ranged from 0.000090 tonne/tonne for C10H22 to 0.026235 tonne/tonne for CH4 while those of the emissions from incomplete combustion ranged from 0.10285 tonne/tonne for H2 to 1.13137 for CO2 tonne/tonne. It was observed that thousands of tonnes of emissions are released into the atmosphere during flaring of sweet natural gas either at complete or incomplete combustion. It is recommended that flaring of natural gas should be reduced to a minimal level to safeguard the environment.
This paper assessed the environmental impact of a telecommunication base transceiver
stations (BTS) located at Cardoso Close, Apapa, Lagos State, Nigeria with the coordinates 6o4392’N,
3o3126’E. The ambient air quality parameters: SO2, NO, CO, CH4 and total suspended particulates (TSP)
were measured using the ITX Emission Analyzer at four sampling points within the base station. The
concentrations of SO2, NO, CO and TSP atthe base station ranged between 0.3-0.5 ppm, 1.9-2.2 ppm,
5.5-7.5 ppm, 101-110 μg/m3 respectively for 24-hour averaging period. CH4 was not detected at any of
the sampling points. A digital Realistic Sound Level Meter was used in measuring the noise level. The
measured average noise levels in all the four sampling points at the BTS studied ranged between 83.1-
88.7 dB (A). Samples of water were collected from boreholes around the base station and were subjected
tophysico-chemical examinations using the ‘standard methods for water and waste water’ 14th edition
prepared by American Public Health Association (APHA). The analyses of the water samples showed
that all the parameters are within limits. To measure the electromagnetic radiation emitted from the
station during the field study, the SPECTRAN HF-4049 RF, an in-situ dosimeter for radio frequency
measurement was used. The results obtained showed that, the measured averageradiation levels in all the
four sampling points within the BTS studied ranged between 0.051-0.054 μW/m2. All the measured
parameters are within safety margins apart from SO2 and NO. SO2 was not traceable to the BTS while NO
was only partly connected with the fossil-fuelled electricity generating sets. The parameters of the
physico-chemical analysis of the borehole water were significantly below limits.
This study identified one hundred samples of woody biomasses in the southwest, Nigerian. The woody biomass samples identified were collected from different saw mills, farms and kitchens in Osun State, Nigeria. The identification of the woody biomass samples was done using literature materials and at a herbarium in the Botany Department, Obafemi Awolowo University, Nigeria, using the vegetative parts of their trees. The identification was carried out to know the numerical availability, the family or English names, the common names and the botanical names of the southwest Nigeria woody biomasses. From the findings, 100 samples of the woody biomasses were identified of 39 families and classes of hard woody biomasses and soft woody biomasses out of which only two are soft and rest are hard. It was discovered that Southwest, Nigeria has the capacity to embark on the massive production of these woody biomasses identified due to her land mass of 77,818 km2 comprising 85 forests. In conclusion, serious investment in the propagation of these energy crops would lead to the production of woody masses to serve as feedstocks in thermal power plants for sustainability in power supply, air pollution control and employment opportunities.
Liquid loading causes undesirable occurrences such as premature death of wells, as well as significant reduction in production. However, most available models consider vertical wells and only a few focus on deviated gas wells. In order to reduce the impact of liquid loading on gas production, gas well load-up should be diagnosed at its early stage so as to proffer adequate solution. Unfortunately, most gas wells will experience liquid loading at some stage or point in their production life. Therefore, it is of utmost importance to predict liquid loading at the early life of such wells in order to develop apt liquid management strategies as corrective measures. Liquid film flow reversal concept has been identified as one of the major concepts responsible for the occurrence of liquid loading in deviated gas wells. This study develops an improvement on Chen's liquid loading model. The model specifically introduces the concept of non-uniform film thickness around the pipe wall, as against previous works which considered uniform film thickness. A modified friction factor is also introduced to account for large film thicknesses around the pipe wall. Results from the model were compared with those of previous models, and data from published literature was used to validate the new model. The new model gave accurate predictions for 11 of 12 unloaded wells while for the loaded wells, the estimated data gave accuracies for 29 out of 30 loaded wells. This then implies that the new model is accurate for predicting liquid loading in deviated gas wells. •Predictions from the new model show a good improvement over existing models.•The uniform film assumption made in Chen liquid loading model was modified, and a different interfacial friction factor was applied.•The method proposed in this study introduces the concept of non-uniform film thickness around the pipe wall as against previous works which considered uniform film thickness.
Most states in Nigeria are faced with the challenge of ensuring a sustainable energy supply and safe waste management. Anaerobic digestion meets the requirements of sustainable alternative fuels and is also an environmental disposal method. Producing clean alternative biogas energy from waste is also one of the best ways to meet these challenges. This study uses a bottom-up resource-oriented approach to assess the biogas potential in Nigeria through the use of organic waste. The objective is to analyse the potential in utilising the available organic waste during anaerobic digestion. The analysis summarises several studies on this issue from 2001 to 2019, and their conclusions are highlighted and used to infer the importance of converting these organic wastes into biogas. The environmental impact of the process is so great that it must be taken into account. However, Nigeria does not have an appropriate and suitable source separation scheme and should invest in waste separation. Source separation or central separation, as the environmental impacts associated with waste management and biogas production, must be considered. The results show the considerable potential of biogas over the next three decades due to rising waste generation and proposed deployment of infrastructure for improving waste collection efficiency.
The operational effectiveness of a fluid catalytic cracking unit largely depends on its catalyst, which is a mixture of zeolite, binder, matrix and filler. The filler plays an active role as it provides the catalyst with physical strength and integrity and also presents a heat exchange platform where more imperative and costly zeolite component can be incorporated. In Nigeria, foreign kaolin clay is used as fillers because it contains lesser impurities when compared to the one indigenous to the country. In contrast, Nigeria bentonite clay have unique properties that can be processed and used as an alternative. This paper evaluates the suitability of kaolin and sodium bentonite from southern Nigeria as fillers in the Fluid Catalytic Cracking Unit. Initial characterisation with the aid of an XRF analysis confirmed the presence of iron oxide impurity on both the local and foreign crude clay (Bavaria, Germany). Wet beneficiation processes were carried out on all clay samples with different reaction times, temperatures and amounts of reagents to reduce impurities. Reaction time at 8 h proved more effective as 77% of iron oxide were removed from both the local and foreign clays. The product properties of the beneficiated samples also revealed iron oxide impurities that reduce impurities from 5.62% to 1.41% for kaolin clay and from 9.84% to 2.77% for bentonite clay. Samples of crude oil and products were tested to determine their physical properties using an Emmetteller Brunauer, a scanning electron microscope, a viscometer, and a pH meter to reveal the impact of the benefits on compliance with API standards. Aside from the increase or decrease of particulate or grain size, the structural modifications reflect the impact of mineral clay in retaining exchangeable cations (nutrients).
This paper assessed the chromium and cadmium emissions from consumption of premium motor spirit (PMS) and automotive gas oil (AGO) across the states, regions and the nation, Nigeria as a whole. This was with a view to determining the levels of per capita and land exposures to the emissions and the associated risks to humans, plants and animals. Annual fuel consumption and toxic transition metals contents were combined to estimate the annual emission rates of chromium and cadmium emissions from combustion of the PMS and AGO for a period of ten years (2009–2018). Per capita and land distributions of emissions were then calculated by using population and land areas, respectively. The results showed that total emission rates from both PMS and AGO were lowest in 2012, with 1,102 million mg/yr of chromium and 3,253 million mg/yr of cadmium, and highest in 2018, with 14,454 million mg/yr of chromium and 39,580 million mg/yr of cadmium. Emission rates per capita were also lowest in 2012, with 7 mg/yr.person of chromium and 20 mg/yr.person of cadmium, and highest in 2018 with 74 mg/yr.person of chromium and 201 mg/yr.person of cadmium. Land distribution was lowest in 2012, with 1.19 mg/yr.km2 of chromium and 3.52 mg/yr.km2 of cadmium, and highest in 2018, with 15.63 mg/yr.km2 of chromium and 42.81 mg/yr.km2 of cadmium. Comparing to regulatory limits, the risks of humans, animals and plants be poisoned are very high. It is recommended that stiff regulations concerning the heavy metal contents of fuels imported and distributed in Nigeria should be created and implemented to mitigate the risks of poisoning to humans, animals and crops.
Nigeria had been standing aloof at exploring her bioresources as a means of combatting her energy cum economic challenges. After some critical examination, the authors showcased Nigerian Palm Industry as a viable biofuel source yet unexplored. Using a combination of some economic and vegetation facts and figures to comparatively analyse, Nigerian oil palm industry to validate the prospect of a sustainable commercial-scale biofuel production that can serve as both affordable alternative cleaner energy fuel for her populace and immense export revenue. The Nigerian government is encouraged to latch onto this bioresource prospect.
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