Studies have shown that adequate attention needs to be paid on processing of solid minerals that are potentially available in Nigeria to address its economic problem. Clays from five major towns in Baruten Local Government Area, Kwara State, Nigeria were examined using ASTM guidelines to determine their suitability for refractory applications. The clay samples were classified as Alumino-Silicate refractories due to high values of Al2O3 and SiO2. The results showed apparent porosity (19.4-25.6%), bulk density (1.83-1.90 g/cm 3 ), cold crushing strength (38.7-56.1 N/mm 2 ), linear shrinkage (4.4 -9.3%), clay contents (52.71-67.83%), moisture content (17.0-23.6%), permeability (68-82 cmsec -1 ), plasticity (16.7-30.4%), refractoriness (>1300 o C) and Thermal Shock Resistance (23-25 cycles) for the clay samples, which were measurable with the established standards for fireclays, refractory clays/brick lining or alumina-silicates and kaolin. Hence, the natural clays could suitably replace imported clays in some refractory applications. Appropriate use of information from this study would improve Nigeria's industrialization and economic diversification.
The impact of specific number of airs to clinker on a clinker cooling process in grate coolers in a cement plant was investigated. Clinker cooling process is a complex process due to the vast number of interacting operating parameters such as: clinker cooler length, ambient temperature, clinker cooler width, clinker cooler drives speed, clinker cooler fan speed, clinker and air mass flow rates, and clinker density and air densities. This research examines heat transfer and multiphase fluid flow analysis as relating to specific number of air to clinker in a clinker cooling system. It employs a physical “dimensionally scaled-down” model. A 3D model of the clinker bed was developed using SolidWorks 2014 based on geometric parameters adopted in the scaled conceptual design after an existing running clinker cooler. The designed model was scaled down by ratio 25:1, that is, existing cooler being twenty-five times higher than the modelled with length 1.3 m, width 0.3 m and variable clinker bed height of 0.3 m, 0.4m and 0.6m as geometric dimensions. Numerical experimentation done involved high temperature clinker entering the clinker cooler from the heating-up furnace (HUF) at 1350 °C, specific numbers of 2.2041 and 1.7959 Nm3/kg clk, air inlet temperature of 32 °C, inlet mass flow rate of air at 0.45 kg/s at clinker 0.15 kg/s. It was observed that at a specific number of 2.2041 Nm3/kg clk at a bed height 0.6 m an optimal energy recoverable efficiency of 70% was recovered into the system and with an improved lower outlet clinker temperature of 68 °C. While, at a specific number of 1.7959 Nm3/kg clk and at a clinker bed height of 0.3 m, the lowest recoverable efficiency of 57.52% was recovered into the modelled clinker cooler and with highest outlet clinker temperature of 168.7 °C. Hence, specific number of airs to clinker also plays a significant role in clinker cooler performance.
There is a continuous demand for refractory materials to meet the increasing expansion of industries and plants. Local clay materials are being explored to augment the inadequate supply of refractory materials. This study therefore evaluated the suitability of locally aggregated kaolin as refractory material. The kaolin was aggregated from Ipinsa kaolin, termite hill materials and bentonite in the ratio 5:4:1 by mass. Chemical analysis carried out on the materials using Proton Induced X-ray Emission (PIXE) Equipment revealed that the kaolin aggregate had a composition of 37.22% alumina (Al2O3) and 51.93% silica (SiO2). The Ipinsa kaolin comprised Al2O3 at 43.05% and SiO2 53.91%, termite hill material (Al2O3 22.69%, SiO2 58.83%) and bentonite had 23.10% Al2O3 and 55.40% SiO2. It shows that Ipinsa kaolin can be used for refractory materials in furnaces, kilns and stoves while the aggregated clay can be used in applications requiring more superior refractory properties. The thermo-physical analysis of the aggregated clay revealed a bulk density of 1.84 g/cm3, apparent porosity 31.54%, linear shrinkage 4.00%, thermal shock resistance 40+ and refactoriness 1900 oC. The refractoriness indicated that the aggregated clay is also suitable for use as ceramic fibre within the temperature range of 1800 and 2000 oC.
This paper compares the rate of biogas production of cattle dung and a mixture of plantain peels with cattle dung. 18kg of cattle dung mixed with 36kg of water were charged to a digester while 9kg each of cattle dung and plantain peels mixed together with 36kg of water were charged to a separate digester. Both digesters were filled to three quarter of their capacity of 88litres. They were subjected to anaerobic digestion for forty days. The digesters were made of mild steel 2mm thick. 297K more characteristic of the ambient temperature was the lowest and 303K which was more of the digesters temperatures were the maximum temperatures recorded. 13998.88N/m2 and 27864.44N/m2 were respectively the initial and highest pressures for the cattle dung digester while 19331.79N/m2 and 27931.10N/m2were observed as the initial and highest pressures for that of the cattle dung and plantain peels mixture. Also 8.4m3/kg and 17416.2m3/kg of estimated specific volumes were obtained for the cattle dung digester in the same manner. Conversely 6.1m3/kg and 27480.7m3/kg were estimated initial and cumulative specific volume for the biogas in cattle dung with plantain peels mixture digester. It was therefore concluded that the mixture of cattle dung with plantain peels produced more biogas than only the cattle dung.
The paper dwells on the atmospheric pollution resulting from the vehicular exhaust discharge at the north gate of the Federal University of Technology, Akure (FUTA), Nigeria. The vehicular traffic census took place at gate on the Ilesha-Akure high way passing in front of the gate for six days. The census was conducted using a digital tally and a stop watch for nine hours at thirty minutes interval daily. The tally was pressed to count each time a vehicle passed both to and from either direction along the road at a chosen point in front of the University north gate. A daily vehicular count was obtained from the ratio of total vehicles to the total time interval of nine hours. Thereafter the average vehicular exhaust discharge, pollution source strength and pollution concentration were determined. At the same time, a data logger was used to measure the meteorological elements of the temperature, the wind speed and the relative humidity of the weather daily. The relationship between the pollution source strength and concentration with the meteorological parameters obtained with data logger, speed and distance covered by vehicles were also determined. The average daily vehicle populations within the time interval being considered were respectively 8280, 8306, 7315, 7210, 8766 and 8491 for the six days in succession. The meteorological data analysis showed that the air relative humidity and wind speed increased with decrease in temperature especially when it rained. The source strength and concentration of pollution decreased with increase in the speed of vehicles and the distance moved indicating that pollutants dispersed faster into the air in the process.
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