Browsing by Author "Nkolokosa, Duncan Elia"

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    Techno-Economic analysis of fuel Briquetting Technologies in Malawi: a case study of Dedza District
    (University of Dar es Salaam, 2016) Nkolokosa, Duncan Elia
    Huge amounts of biomass waste continue to accumulate in Malawi’s major forest reserves and in some major processing industries. Large heaps of sawdust existing in most of Malawi’s forest reserves, which have no proper means of disposal, are causing land, water and air pollution. Using cost effective and efficient technologies, these wastes can be converted to fuel briquettes, which can be used for cooking and heating applications, and can reduce demand for charcoal and firewood in the areas where these wastes are available. Loose and small particle biomass wastes can be converted to briquettes through the use of piston, screw or roller press technologies. The choice of the technology used depends on whether the desired products are carbonized or uncarbonized briquettes. In biomass briquetting, the scale of production depends among other things on economic characteristics of the technology and available bio-wastes. In this research, four bio-wastes namely, sawdust, rice husks, maize cobs and groundnut shells were investigated. Both qualitative and quantitative data were collected by the use of questionnaires, interviews and measurements. The questionnaires targeted biomass briquettes stakeholders, which include producers, users and government agencies. Tests were also carried to determine physical characteristics of four available bio-wastes. A cost-benefit analysis method was used to select an optimum briquetting technology. Results show that sawdust has the highest calorific value (18.53MJ/Kg) and high fixed carbon (24%) compared to the other available bio-wastes. Cost benefit analysis revealed that, it is more economical to use piston press briquetting technology for the production of uncorbonized briquettes. Piston press got a high Net present value (0.77 million USD$) and high internal Rate of Return (42.8%) than Screw press briquetting technology which got 0.31 million USD$ and 26.1% net present value and internal rate of return respectively.