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This study produces liquid fuel from waste automobile tyres via thermal pyrolysis purposely to investigate the feasibility of replacing conventional fuel with pyrolysis oil in internal combustion engines. Shredded automobile tyres were pyrolysed in an electric-powered pyrolysis reactor and the oil obtained was treated with H2SO4 to remove sludge and to reduce its odour. The treated oil was distilled, and the products obtained have properties similar to gasoline and diesel fuels. The light tyre pyrolysis oil (LTPO) was blended with regular gasoline and the various blends obtained were used in powering an electric generator, and the fuel consumption rate in the generator was observed to reduce with an increase in pyrolysis oil content. Analysis of the exhaust flue gases showed that gasoline-LTPO blends gave a significant reduction in the CO levels. However, the unburnt hydrocarbon (HC) content of the exhaust stream increased with the LTPO content, with the blends containing 60% LTPO having the highest HC level. The conclusion from the study revealed that the tyre pyrolysis oil could possibly replace conventional fuels in internal combustion engines, and the application of the Exhaust Gas Recirculation (EGR) approach could resolve the issues of high HC contents in the exhaust stream.

This paper investigated the effects of laboratory synthesised rocket composite propellants’ formulations on propellant performance parameters using response surface methodology (RSM). For the sake of a safe environment, the propellant is made of chemical constituents that have less severe effects on air quality. Experimental measurements of propellant performance parameters were carried out using the ballistic evaluation method. The thrust generated during combustion, the burn time and the propellant combustion temperature were measured using a data acquisition facility equipped with a button load cell and a thermocouple. Specific impulse, density, temperature, characteristic velocity, molecular weight and heat ratio were computed from the measured parameters. The resulting optimum rocket composite propellant formulations were 65.1%, 18.1%, 9.1%, 3.6%, 2.2% and 1.9% for the oxidiser, binder, fuel, opacifier, burning rate enhancer and catalysts, respectively. The corresponding performance indices i...

Nigeria’s energy supply in the form of electricity has been erratic and unreliable in recent time that people now depend on their own power generation in order to meet demands. Thus majority of the populace have to depend on traditional fuelwood for cooking without knowing the impacts of air emissions from it. This study estimated the ground-level concentrations of the air pollutants emitted from the fuelwoods using the American Meteorological Society-Environmental Protection Agency Regulatory Model (AERMOD). The maximum 24 h averaging ground-level concentrations were 6.378–87.319, 1.546–75.164, 0.079–2.759, and 0–0.164 µg/m3, respectively for CO, HC, NO, and SO2. With this all stakeholders will be properly guided on the usage of fuelwood with minimal negative impact.

Purpose The introduction of mobile telecommunication services in Nigeria led to the development of base transceiver stations (BTS) across the country. Inadequate power supply from the national grid has led to massive use of diesel-fueled back-up generators (BUGs). The purpose of this paper is to attempt to quantify and inform relevant stakeholders about air quality implications of BTS BUGs. Design/methodology/approach Seven major telecommunication network operators were identified. Emission factor approach was used to estimate the quantity of important air pollutants such as NOx, CO, SO2, PM10, PM2.5, PAH and TVOC that are emitted from the use of the BUGs based on fuel consumption rate and generators’ capacity. Fuel-based emission inventory and emission factor from the United States Environmental Protection Agency AP-42 and National Pollution Inventory were used to estimate pollutants emission from diesel-powered generators used in the BTS sites and amount of diesel consumed. Land distribution and per capita dose of the estimated pollutants load were calculated. Findings The study showed that the deployment of BUGs will lead to increase emissions of these air pollutants. The states that are most affected are Lagos, Kano and Oyo, Katsina and Akwa Ibom states with respective total air pollutants contribution of 9,539.61, 9,445.34, 8,276.46, 7,805.14 and 7,220.70 tonnes/yr. Originality/value This study has estimated pollutant emissions from the use of diesel-fueled BUGs in mobile telecommunications BTS sites in Nigeria. The data obtained could assist in policy making.

The current electricity shortage from Nigeria’s national grid and the scarcity of refined petroleum products including kerosene which is used for domestic purposes make the use of fuelwoods more dominant in the country; especially in the rural areas. Air emissions from open burning of pre-determined quantity of some common fuelwoods identified in regions were characterized for gaseous air pollutants using the E8500 combustion analyzer. The measured concentrations were used to calculate emission factors of the air pollutants. The emission factors for the gaseous emission from the fuelwoods were 181.84–6547.57 g/kg for CO, 44.07–2986.40 g/kg for HC, 2.24–267.36 g/kg for NOx while SO2 had 0.0–9.87 g/kg. This study establishes that Gliricidia sepium had the minimum emission factor for all the considered gaseous pollutants except for SO2, thus all stakeholders considering the adoption of fuelwood in the country’s quest for increased energy mix can be properly guided on the pollutants associated with th...

This paper assessed the environmental impact of a telecommunication base transceiver stations (BTS) located at Cardoso Close, Apapa, Lagos State, Nigeria with the coordinates 6°4392’N, 3°3126’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.

The increase in price of the available refined petroleum products for local consumption in Nigeria had led to the emergence of indigenous technology for petroleum refining in some parts of the Niger Delta region. This study, therefore characterized and quantified artisanal refineries’ gaseous emissions for possible air pollutants based on various unit operations involved and evaluated their impacts. It measured the emissions directly from source using E8500 Portable Combustion Analyzer. It also categorized oven sizes/processing capacity of the refineries into various ranges in order to estimate emissions according to processing capacity. The result revealed that; pollutants emission varied significantly between the unit operations and increased with increase in processing capacity. When the emissions were compared with daily limits set by the Environmental Guidelines and Standard for Petroleum Industry in Nigeria (EGASPIN) 2002, the emissions (CO, NOx, and SO2) breached the available set limits. While with the Federal Environmental Protection Agency (FEPA), 1991 set limits for emissions from stationary source; HC and CO breached their limits. SO2 and H2S breached their lower limits but were below the upper limit, while NOx emissions were found within its set limit. The study concluded that, Nigeria Artisanal Petroleum Refineries are sources of air pollution, as they impact the host environment., Environmental science; Chemical engineering; Environmental chemical engineering; Atmosphere modelling; Air quality; Environmental chemistry; Environmental hazard; Environmental pollution; Artisanal refineries; Characterisation; Air pollutants; Crude oil; Niger-Delta.

The dispersion models were used to estimate or predict the concentration of air pollutants or toxins emitted from sources such as industrial plants, vehicular traffic or accidental chemical releases. In this study, the Industrial Source Complex Short Term (ISCST3) emission dispersion model was used to measure the ground level concentration of criteria air pollutants within 50 km radius of location. This model considered emissions from major point sources of pollutants in four existing and twenty-three proposed Nigeria petroleum refineries. The obtained ground level concentration for 24-hr averaging periods of the criteria air pollutants at sensitive receptor around each of the refineries was compared with the National Ambient Air Quality Standards (NAAQS) of Nigeria, World Bank and World Health Organization (WHO) to determine their level of compliance. The highest ground level concentration predicted to be 450 - 1875 μg/m3 for 24-h averaging period was obtained at Tonwei Oil Refinery, Ekeremor Local Government, Bayelsa State, while the lowest ground level concentration predicted to be 0.0099 - 0.1 μg/m3 for 24-h averaging period was obtained at Amakpe International Refinery, Eket Local Government, Akwa Ibom State. Percentage set limits of criteria air pollutants ranging from 0.02% to 94.5% are within the set standard limits and no health risk is associated with areas around the plant’s locations while percentage set limits of criteria pollutants ranging from 1.1 to 55.6 folds of the standards exceed the maximum permitted limits, hence affecting areas around the plants. The air quality standards guiding petroleum refinery emissions must be strictly considered, in order to ensure that the ground level concentrations do not exceed the required standard limits and prevent the adverse effects of air pollution in the Nigeria airshed.

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.

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.

Deleterious impact of lead from the use of motor fuels is of major concern. Lead levels of gasoline and diesel samples from States in Southwestern Nigeria were analysed by Atomic Absorption Spectrometer, according to the standard ASTM D3237-97 method. Lead concentrations ranged from 0.491–1.903 mg/L for gasoline and 2.301–10.97 mg/L for diesel. Estimated lead levels in gasoline were below the Department of Petroleum Resources (DPR) Nigeria limit of 3.37 mg/l. Percentage lead contributions from gasoline and diesel fuel consumption were minimal due to various fuel lead-level regulations that have been established over the years.

Acetic acid constitutes major component of waste water effluent in petrochemical and fine chemical industries but its recovery poses a serious environmental challenge in the industries. In this work, nonlinear model for multi-input multi-output reactive distillation process was developed for the treatment of waste water containing 30% g/g of acetic acid using fuzzy model technique based on autoregressive with exogenous inputs (ARX) models. It was aimed at obtaining a simplified model which should have essential dynamic behaviour of the process suitable for applications such as control design and dynamic optimization. Data sets used for the model development were obtained from simulated model built in CHEMCAD environment. Reflux flow rate and reboiler heat duty were used as input variables while ethyl acetate top product purity and acetic acid fractional conversion were used as output variables. Structured nonlinear parameter optimization method (SNPOM) was used for parameters estimation to effectively characterize the systems. The percentages of fitness for top product ethyl acetate purity and acetic acid fractional conversion were found to be 85.35% and 82.95%, respectively. The residual analysis carried out on the model showed that the proposed model was able to capture nonlinear dynamic behaviours of the process.

PurposeThe aim of this paper is to provide basic information on the types of particulate cyclones separators used in the chemical and process industries, their principles of operation and factors affecting their performance.Design/methodology/approachA general review of the types of particle cleaning cyclones used in the chemical and process industries was carried out and the principles guiding their operation and performance discussed. Information which could aid the choice of cyclone for new applications is also discussed.FindingsIt was concluded that the choice of cyclone for any application is associated with a trade‐off between two contrasting performance indicators (collection efficiency and pressure drop). Adequate and accurate data gathering is essential right from the design stage for smooth operation of cyclone.Originality/valueThe paper highlights the general principle of operation of cyclone separators and the factors that affect their performance.

This study assessed the factors hampering innovation and knowledge sharing in indigenous oil and gas firms in Nigeria. The aim was to provide information that will increase knowledge sharing among the indigenous in the sector and create added value, which is needed to improve the local content within the industry. The study used primary and secondary data sources. One hundred firms were sampled. A structured questionnaire was administered to the firms. This was supplemented with field observations and interviews. A total of 100 questionnaires were administered to heads of production and engineering departments in the firms with a 70% response rate. Secondary data were obtained from published sources. The data were analysed using descriptive statistics. The study found that the challenge of innovation centred on high costs, lack of skilled personnel, especially in their R&D departments and poor economic conditions in the country. However, an estimated 30% of the firms were innovation active in the period 2...

The study examined the types and intensity of innovations in the indigenous Nigeria's oil and gas servicing sub-sector. The study used primary and secondary data sources, 100 firms were purposefully selected and sampled, focusing on the period between 2001 and 2010. A total of 400 questionnaires were ad min istered of wh ich 70% were returned and found suitable for analysis. The responses were aggregated such that the unit of analysis was the firm. Secondary data were sourced fro m the internet and other published sources. The data so obtained were analy zed using descriptive and inferential statistics. Of the 4 types of innovation that the study examined, o rganizat ional innovation was the most prevalent (46%) while diffusion-based innovation was least (10%). Product and process innovations were implemented, respectively, by 17% and 22% of the firms. Innovation intensity was lo w: only two patents were granted to the firms within the period 2007-2010, level of organizat ional learning was lo w, the nu mber of R&D staff was low while the impact of innovation on firms' performance was expressed in increase in profit, process improvement and new product development. In conclusion, our study found out that the overall innovation capability of the firms was expressed in organizational innovations.

This study examined the factors that influence innovation and competiveness in the indigenous Nigeria's oil and gas servicing firms. Th is was done with a view to making appropriate strategic recommendations to enhance firm-level innovativeness so as to increase indigenous participation in the sub-sector. The study, wh ich used primary and secondary data sources, was based on a sample of the indigenous oil and gas servicing firms in Nigeria. Four types of questionnaire were ad ministered in each firm. A total of 400 questionnaires were administered on heads of Production, Engineering, Finance and Administration in the firms out of which 70% were returned and found suitable for analysis. This was supplemented with field observations and interviews. Secondary data were sourced fro m the internet and other published sources. The data so obtained were analysed using descriptive and inferential statistics. The technological factors that accounted for the innovation performance included the educational qualifications, training and prior work experience of the heads of technical department, nu mber of r&d staff and training, innovation, and, r&d in- vestment. The important non-technological factors included interaction with co mpetitors, consumers, suppliers and training institution. In conclusion, our study found out that the most important factors that influence innovation in the sub-sector are r&d ex- penditure and training.

One of the strategies being developed in Nigeria to increase the presently installed electricity generation of 6159 MW to the required 30,000 MW is the adoption of electric thermal plants. An emission factor approach is used in this paper to study the emission of uncontrolled air pollutants from all the existing and proposed thermal plants in the country. Calculations are performed to study the distribution of carbon monoxide (CO), oxides of nitrogen (NOX), particulate matters (PM), sulphur dioxide (SO2), and volatile organic compounds (VOCs). The estimated emissions ranges are 978–24,607, 1635–41,148, 37–924, 19–472, and 11–286 ton/annum for CO, NOX, PM, SO2, and VOCs, respectively. The present locations of these plants across the country are characterized by skewed emission distribution both per capita and across the land. Given the potential environmental and health impacts of these emissions, several measures are suggested to reduce future impacts and assist the country in achieving sustainable development.

The ISCST-3 model has been used to study the ground level concentrations of carbon monoxide (CO), oxides of nitrogen (NOX), particulate matter less than 10.0 microns in diameter (PM10) and sulphur dioxide (SO2). The purpose was to predict air quality effects from an integrated oil and gas project (IOGP) proposed for the Niger Delta, Nigeria. The emissions of 12 elevated point sources for criteria air pollutants were considered with eight different scenarios. Both natural gas-fired and diesel (AGO) fired equipment were considered for the identified emission sources. Five years of hourly meteorological observations were used in the prediction of the ground level concentration of the pollutants. The model outputs show a general maximum ground level concentration between 0.5 – 3.5 km, with easterly and north-easterly receptors having the greatest concentration. The pollutants emitted in the greatest concentration in their order of magnitude were CO, NOx and PM10. Maximum ground level concentration for 1, 8 and 24 – hr periods for CO were below regulatory standards (less than 10 %) for scenarios 1 – 4 when the fuel is natural gas. The 8 – hr ground level concentrations were about 1.3 folds of the World Bank Standard in scenarios 5 – 8 when the fuel sources are switched to AGO. However in these scenarios, the Nigerian environment and petroleum ministries' emission limits were not breached for all the averaging periods. Modelled NOX concentrations were significant in all the scenarios except 3 and 4. Though NOX concentrations were within the standards for all the averaging periods in scenarios 1 – 4, except the 1 – hr limit that was breached in scenarios 1 and 2, these concentrations were about 1.1 – 2.8 folds in all the averaging periods of all the standards in scenarios 5 – 8. The predicted PM10 and SO2 concentrations are all below the guideline limits. If the use of AGO is completely avoided in the entire life of the proposed IOGP, the air quality of its immediate vicinity can be protected. Furthermore, the declaration of a radius 1.75 km natural forest buffer around the plant and continuous monitoring of ground level concentrations of CO, NOX, PM10, and SO2 may further assist in guaranteeing the safety of people in terms of air quality. The study shows the need for policy formulation that will integrate comprehensive cumulative impacts assessment of air quality in the environmental laws regulating the gas development projects in Nigeria.

There exists a wide energy supply/demand gap in Nigeria. The local generation of electricity meets only 31% of the demand of 10000 MW. By contrast, only 39.6% of the total installed capacity for electricity generation is achieved, owing to aging infrastructure, etc. The energy demand/supply pattern and infrastructure critically reviewed thus suggested the need to increase the electricity generation capacity. Furthermore, Nigeria flares 77% of her associated natural gas. Apart from the environmental penalties that flaring represents, in monetary terms, over the 110 years' life of Nigeria's gas reserves, a conservative estimate of the cost of the gas so-flared was $330 billion (based on $20/barrel average price of crude). It was safely inferred that the way forward in meeting the country's energy demand should include a strong element of gas utilization. In previous publications by this group, it was established that while domestic cooking could reduce the flared gas by about 5.4%, a cohesive policy on associated gas use for electricity generation could eliminate gas flaring. For domestic utilization of the associated gas, burner design and safety concerns were identified as the key challenges to overcome. The paper reports the effectiveness of odorizers in leakage detection/ prevention by the local consumers. It also discusses the issue of prevention of gas explosions. The previous cases of gas accidents were reviewed. The safety approaches proffered in the paper identified the relevant areas of research for safe delivery and consumption of natural gas in Nigeria.

Several research findings confirmed that gaseous emissions and thermal radiation emanate from flaring activities during separation of oil from gas in the petroleum upstream operations. This, coupled with identified degradation potential of flares, makes flaring of about 71 million m3/day of associated gas a great concern. In this paper, several efforts hitherto made by government and organized private sectors at monetizing associated natural gas being flared on daily basis in Nigeria were reviewed. Domestic market development, if adopted, could eliminate routine gas flaring by 2008, meeting a goal set by Nigerian Government. Various scenarios considered showed that relatively minor amounts of natural gas could be consumed domestically for cooking; the balance would be absorbed by thermal electricity generation. It could lead to total consumption of between 92 and 140 million m3/day of natural gas in the country, representing a fraction of the domestic energy market.

Various impacts of direct venting of natural gas into the environment, both in the upstream and downstream petroleum operations, often compel the chemical engineer to specify air pollution control equipment for installation on new and existing platforms/facilities. Flares, a special class of such equipment, are considered in this paper. The major types of flares used in the oil industry are reviewed and the principles guiding their operation and performance discussed. Information which would aid the choice of flare system for new applications is also discussed.

In aviation industry, weather forecast is necessary to avert air disasters if flight must take place. In the crude oil producing sectors, there is a need also for a perfect knowledge of anticipated gaseous emissions from associated natural gas of known composition being flared on daily basis through combustion activities under several operating conditions. This will help in the control of gaseous emissions from these flares and thus in the protection of their immediate and distant environment against environmental degradation via air pollution. It is in the light of this that a theoretical model employing a set of material balance equations was investigated with natural gas of Nigerian origin as combustibles using a developed computer program. Operating conditions favouring complete combustion generate the least gaseous emission specie (CO 2 only) while those that favour incomplete combustion and high temperature produce CO, NO, and NO 2 as additional species if the natural gas contains no sulphur compounds. In the presence of H 2 S, SO 2 is released in addition. The presence of other impurities, which are combustibles in the natural gas, might likely change these entirely. There is a strong correlation between emission quantity and amount of natural gas available for combustion. Carbon contents of the natural gas plays a prominent role in determination of quantity of air requires for combustion. This in turn determines the combustion reaction type (complete or incomplete). On the average, anticipated gaseous emission from natural gas of Nigerian origin with annual flaring rate of 25838.35 m 3 is predicted by the model to be 1.72×10 5 , 5.48×10 5 , 1.611×10 5 , 2.252×10 5 , and 1.16×10 3 kg for CO 2 , CO, NO, NO 2 , and SO 2 respectively. Confirmation of the presence of these gaseous pollutants from the various combustion reaction types investigated coupled with their overall high emission concentrations predicted are considered enough reasons for Nigerian Government to review its present natural gas policy. Routine flares in the country should be minimised for gaseous emission reduction.

The sections in this article are 2.1 Introduction 2.1.1 Energy Sources 2.1.2 Hydrocarbon Destruction in Gas Flares 2.2 A Review of Global Warming Concept 2.2.1 Water Vapor 2.2.2 Carbon Dioxide 2.2.3 Methane 2.2.4 Nitrous Oxide 2.2.5 CFCs 2.3 Fundamentals of Natural Gas Combustion 2.4 World Natural Gas Reserves, Production, Consumption and Destruction 2.4.1 World Natural Gas Reserves 2.4.2 World Natural Gas Production 2.4.3 World Natural Gas Consumption 2.4.4 World Natural Gas Destruction 2.5 Global Warming Contribution from Natural Gas Combustion 2.5.1 Global Warming Contribution from Natural Gas Combustion in Energy Consumption 2.5.2 Global Warming Contribution from Natural Gas Combustion in Flaring Activities 2.6 Control Measures for Global Warming from Natural Gas Combustion 2.7 Conclusion Keywords: global warming; climate change; natural gas; combustion; gas flares