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The purpose of this study is to examine the emissions effects resulting from the use of low pour fuel oil (LPFO) and diesel fuels in industrial steam boilers operation. The method of ultimate analysis of the products of combustion and emissions of pollutant analysis were used to estimate the annual rate of emissions of boilers. The results shows that the levels of uncontrolled boiler emissions on the environment can lead to increased greenhouse effects, global warming, and pollution and toxilogical impacts on human health. Only carbon monoxide emission was found to vary with the levels of oxygen generation in the products of combustion, while other substances were generally in relation to constituents and rates of consumption of fuel.

Abstract: The aims of this study were to determine direct input energy, indirect energy and other energy use indices in mango production in a group of mango plantation of a research farm in Nigeria. The study also estimated the economic indices of mango production in the study area and energy potentials of mango by-products. The average energy consumption of the plantations investigated in this study is 15,015.16 MJ ha−1. Out of the total energy, 93% was direct and 7% was indirect. Renewable energy accounted for 21% and energy usage efficiency was found to be 1.3. The total energy input into the production of 1 kg of mango was estimated to be 0.70 MJ. The dominant contribution to input was energy in the form of diesel used in tractor operation and captive power generation (56%), followed by human labor used for land preparation, cultural practices and harvesting (33%), machinery (5%) and chemicals, mainly herbicides (4%). The use of energetically available residues of mango could give an average value addition of 57,067 MJ/ha. The cost of mango production per hectare was found to be 2246 $ ha−1. As a result of benefit-cost ratio value (1.24), energy use efficiency and the energy value addition from mango residues, mango production was found to be economically efficient in the study area. [Copyright &y& Elsevier]

Abstract: Energy use patterns and utilisation efficiencies in 40 factories producing palm kernel oil (PKO) in southwestern part of Nigeria were studied. The factories were stratified into small, medium and large scale categories based on the mode of operations and production capacities. Questionnaires were administered on the factories to obtain historical data on petrol, diesel and electricity consumption and PKO production outputs for seven years (1998–2004). Energy use efficiency indicators employed include: energy intensity (EI), energy cost per unit product (EC/P), energy ratio (ER), food energy ratio (FER) and percentage oil yield by weight. Results of the study indicated that averagely, 0.58, 0.53 and 0.74GJ/103 l of PKO were needed in the small, medium and large PKO factories, respectively. The average food energy ratios in the small, medium and large mills are 2.48, 2.53 and 2.14, respectively. The corresponding values of PKO conversion ratio are 0.43, 0.50 and 0.35. Electrical energy consumption in medium and large mills was lower than thermal energy due to irregularity and decline in electricity supply from the national grid. The results of the study has provided required baseline information needed for budgeting, comparison of yearly energy consumption, forecasting energy requirements and planning expansion in PKO factories. [Copyright &y& Elsevier]

Abstract: Energy and exergy studies were conducted in an orange juice manufacturing industry in Nigeria to determine the energy consumption pattern and methods of energy optimization in the company. An adaptation of the process analysis method of energy accounting was used to evaluate the energy requirement for each of the eight defined unit operations. The types of energy used in the manufacturing of orange juice were electrical, steam and manual with the respective proportions of 18.51%, 80.91% and 0.58% of the total energy. It was estimated that an average energy intensity of 1.12MJ/kg was required for the manufacturing of orange juice. The most energy intensive operation was identified as the pasteurizer followed by packaging unit with energy intensities of 0.932 and 0.119MJ/kg, respectively. The exergy analysis revealed that the pasteurizer was responsible for most of the inefficiency (over 90%) followed by packaging (6.60%). It was suggested that the capacity of the pasteurizer be increased to reduce the level of inefficiency of the plant. The suggestion has been limited to equipment modification rather than process alteration, which constitutes additional investment cost and may not be economical from an energy savings perspective. [Copyright &y& Elsevier]

Abstract: This work deals with a study on estimation of energy consumption in eight readily defined unit operations of cashew nut processing. Data for analysis were collected from nine cashew nut mills stratified into small, medium and large categories to represent different mechanization levels. Series of equations were developed to easily compute requirements of electricity, fuel and labour for each of the unit operations. The computation of energy use was done using spreadsheet program on Microsoft Excel. The results of application test of the equations show that the total energy intensity in the cashew nut mills varied between 0.21 and 1.161MJ/kg. Electrical energy intensity varied between 0.0052 and 0.029MJ/kg, while thermal energy intensity varied from 0.085 to 1.064MJ/kg. The two identified energy intensive operations in cashew nut processing are cashew nut drying and cashew nut roasting, altogether accounting for over 85% of the total energy consumption in all the three mill categories. Thermal energy, obtained from diesel fuel, represented about 90% of the unit energy cost for cashew nut processing. The developed equations have therefore proven to be a useful tool for carrying out budgeting, forecasting energy requirements and planning plant expansion. [Copyright &y& Elsevier]

Purpose – The cheapest and most rapidly available metal for agro-processing equipment fabrication in Nigeria is plain carbon steel. However, there are some aggressive ions present in raw agricultural and food products, which may attack the steel components of these processing machinery, resulting in their untimely failure in service. The present study investigates the effect of fluid squeezed from cassava tuber on the corrosion behaviour of mild steel. Design/methodology/approach – The investigation involved periodic weight loss measurements of 0.8 per cent carbon and 0.36 per cent carbon steel rods as they were exposed to cassava fluid. The relationships between loss in weight of the exposed samples and exposure period were determined. Models were developed to relate corrosion rate in each environment with total surface area and exposure period. Findings – The results show that 0.36 per cent carbon steel was less affected by corrosion than 0.18 per cent carbon steel, with corrosion intensity in both cases, increasing with duration of immersion. Generally, there was low level of corrosion resistance (high corrosion rate) by the two steel materials. The correlation coefficient between the experimental values of corrosion rates and predicted values (using the developed models) was high. Originality/value – In food and agricultural industries, product quality, health and sanitation issues are the major concerns. The industries cannot tolerate corrosion deposits in the manufactured products. Hence, material selection for machinery fabrication is essential. In line with this, the results of this study indicate that mild steel materials are unsuitable for use in cassava processing without some forms of surface treatment. [ABSTRACT FROM AUTHOR]

Purpose – Because of the peculiar nature of food and agro-processing industries, the industries cannot tolerate corrosion deposits in their production lines. Hence, there is the need to account for corrosion control before and during the production operations. This is more so in Nigeria where there is little or no proper accountability of corrosion cost in all production system. Design/methodology/approach – The industries investigated were grouped into: meat and meat product, dairy and milk, beverages and brewery, confectionery and agro-processing centres. Questionnaires and interview pro forma were used to collect information from ten major factories/outlets in each category. The study involved the use of life cycle costing to assess corrosion management alternatives and to determine the annualized value of each option. Findings – Among the corrosion prevention methods identified in the industries, greasing gave the least cost contribution (15.9 percent) to the total cost of corrosion prevention followed by painting (17.97 percent) and cleaning (66.14 percent) in that order, while the contribution of each corrosion maintenance method to the total cost of corrosion maintenance was, respectively, 13.08, 7.23, 20.73 and 58.96 percent for annual maintenance, repair, rehabilitation and wages of workers. Originality/value – This study reveals some of the control measures commonly adopted for minimizing corrosion damage in some selected food and agro-processing industries in Nigeria. It also investigated the cost implication of each measure and how it affects the present value of processing machineries in each industry. The results of the study have created a state of awareness of corrosion problems to stakeholders, which would encourage preventive actions. [ABSTRACT FROM AUTHOR]

Purpose – The purpose of this paper is to investigate tractor maintenance practices and costs in Nigeria with a view to making replacement decisions and for overall farm budgeting. Design/methodology/approach – The information was obtained via a structured questionnaire. Tractor owners were grouped into three categories: government agricultural settlements, established farms, and individual farms. Data used for analysis were collected from 60 farms located in major farming centers of the southwestern part of Nigeria. The report includes the formulation of repair equations, which relate tractor repair cost as a percentage of initial purchase prices to cumulative hours of use. Life cycle costs of three commonly-used tractors were also estimated. The derived equations, which showed that the repair costs per hour increased with hours of use, were used to obtain the life cycle cost of each tractor model in different tractor owners' farms. Findings – The proposed equation was found to be the best fit with coefficient of determination (R2) ranging from 0.992 to 0.996 for tractors in the three user categories. The trend observed in the life cycle costing of the three common tractors gave the general picture of when to replace each of the tractors based on the strategies being adopted by the tractor owners. Practical implications – The results of this study would serve as baseline information to tractor owners regarding optimum use of tractors for minimizing repair and maintenance cost per hour and for making replacement policy. It would also be helpful to government and other agencies for future planning in the provision of tractor services to the farmers at relatively lower repair and maintenance cost. Originality/value – Proves that a reduction in repair costs by careful operation and adequate maintenance could result in a significant reduction in tractor ownership costs. [ABSTRACT FROM AUTHOR]

Purpose – This paper aims to investigate the safety practices in some selected agro-allied industries in south-western Nigeria with a view to analysing the degree of safety awareness; adequacy of safety equipment; extent of enforcing safety rules; effectiveness of safety-related activities and economics of safety programme. Design/methodology/approach – A case study method of investigation, field study guidelines and binary variable were used and information gathered from 36 industries was documented. The data collected were analysed using mean, percentage and standard mathematical models. The analyses carried out on the data gathered are presented on the following: occurrence of accidents, causes of accidents, damages resulting from accidents, accident prevention activities and economic implications. Findings – Three classes of accidents are identified as fatal, serious, and minor. The results showed that minor accident has the highest frequency of occurrence of 304, while fatal accident has the least frequency of occurrence of 17. However, serious accident has the greatest economic implication, accounting for annual average loss of $4.97 millions. Also, nine causes of accidents are identified, out of which faulty equipment is common to all industries. And eight accident prevention activities are identified, amongst which standard operating procedure, good housekeeping and on-the-job training are commonly being practised, while provision of safety handbook and policy is least practised. Originality/value – This paper has described the safety practices in 15 agro-allied industries with an organised safety programme in South Western Nigeria. The study has investigated the extent of enforcement of safety rules; safety awareness; and economic implication of accidents from this sector for the national economy. [ABSTRACT FROM AUTHOR]