Design and fabrication of a wind turbine blade

A wind turbine blade design had been studied and fabricated at the CSIR-Institute of Industrial Research, Accra. Earlier turbine blades were manufactured from seasoned wood. The designed blade reported in the study was fabricated from fiberglass and epoxy resin compositions using wood for the mould pattern. The design is of the three-blade type for wind turbines which can be made from simple objects such as barrels. Dimensions and weights were measured to determine the possibilities of its performance. Factors that affect the spinning of the blade include the weight, blade count and its aerodynamic features. The new blades are assumed to be more reliable and efficient than wholly wood design. The calculated wind speed and power density at hub height of 12 m were 4.5 ms-1 and 149 W, respectively. The difference in the blade masses were reduced in the range between 39.2 and 52.6 per cent

Spray characteristics of conventional and electrostatic pressure-swirl nozzle

Spray characteristics of conventional and electrostatic pressure-swirl nozzles demonstrated on oil burner have been studied. Conventional nozzles use other means of energy to disintegrate liquid into droplet sizes withoutcharging the drops during application. Charge injection mechanism was adopted for the electrostatic nozzle, where the specific charge density, breakup length, spray angle and sauter mean diameter were measured parameters. Three nozzles with orifice diameters of 0.256, 0.308 and 0.333 mm at injection pressures of 0.7, 0.9, 1.1 and 1.3 MPa were used to study the spray characteristics. For the electrostatic nozzle, voltages ranging from 5to 12 kV were applied using a high voltage source with a negative polarity. Comparison of the spray characteristics between the conventional and electrostatic nozzles indicated that the electrostatic nozzle was superior tothe conventional nozzle, due the effect of voltage on the surface tension of the liquid being sprayed

Combustion efficiency of a pressure-swirl nozzle burner

No Abstract

The potential of using organic side-streams produced in Ghana for generation of bio-fuel

Bio-fuel can be generated from organic side-streams of maize, rice, millet, sorghum and groundnut by using fast pyrolysis technology. Data on side-streams of these crops were obtained from the Ministry of Food and Agriculture (MoFA) in 2010 for the study. The study shows that the estimated total crop side-streams generated was 3,475,413 t of which 2,345,903.5 t of bio-fuel can be produced, given a potential energy equivalent of 42,226 PJ/y. The result shows a growth rate of 12.9 per cent in energy equivalent potential for synthetic fuel production as compared to the estimated production in 2009. Northern Region had the highest energy potential of 9,676 PJ/y (22.91%) of the total energy equivalent of bio-fuel, whereas, Greater Accra Region had the lowest with 183 PJ/y (0.43%). It is recommended that the available energy potential at the three northern regions of Ghana be utilised effectively when renewable energy policy is improved for a wider applications of side-streams from crops

Design, construction and test operation of a thermal incinerator for medical wastes at Abokobi Health Centre, Ghana

The primary factors considered in the design and construction of a modified De-Montfort type intermittent incinerator for combusting medical wastes were the waste types, fuel, chimney size, and flue gas residence time. The design analysis was based on flue gas flow rate of 0.13 m3/s, maximum primary chamber temperature of 870 °C and minimum ambient temperature of 27 °C. The total flue gas residence time of 6.9 s was achieved for the three chamber system of 0.9 m3 total volume. The medical wastes generated from the four medical facilities in Ga East District (Ghana) consisted of infectious sharp objects, syringes, wound dressings and gloves; which were incinerated at a throughput of 80 kg/day with destruction efficiency of 98.47 %, using fuelwood as primary fuel. The natural convection thermo-fluid flow was controlled by ambient wind speed of ~ 3.8 ms-1, at temperature of 31.5 °C. The primary combustion chamber temperature attained was ~ 516 °C, while the third chamber temperature reached 760 °C, which ensured complete combustion of the wastes with reduced particulate matter emissions. At optimum operating capacity of 0.6 m3, up to 4 cycles of incineration were done in a day, each cycle lasting about 80 minutes

Anaerobic co-digestion of cassava peels and manure: A technological approach for biogas generation and bio-fertilizer production

The modern global society faces great challenges in supply of energy and management of wastes in sustainable ways. One way of resolving the local challenges is to develop environmentally appropriate and socio-economi-cally viable biotechnological processes for converting biomass to energy. The general principles of anaerobic bio-digestion, digester design and features of bio-digestion are presented in the feature article, focusing on the prospects of utilizing cassava peels as a readily available lignocellulose feedstock for co-digestion with manure for the production of biogas and bio-fertilizer. Aside of the high cyanogenic properties, cassava peels would re-quire pre-treatment before use as a substrate, hence, a multi-stage and high rate digestion system might be adop-ted in efficient digestion of cassava peels. To optimize carbon-nitrogen ratio for efficient digestion, cassava sh-ould be co-digested with manure. The socio-economic benefits of the anaerobic co-digestion technology and key policy measures to be implemented to harness bio-energy from agricultural wastes are also outline