Drying Of Agricultural Products By Geothermal Heat In Kenya

Abstract

The main objectives of this work were to carry out a prefeasibility study on the use geothermal heat in drying of agricultural product in Kenya and design of a geothermal drying system for a selected crop at a preferred site. The study used the yearly data from the ministry of agriculture, livestock and fisheries to obtain the quantity of each of the main cash and food crops in the Kenya. The data of these crops from 2010 to 2014 was used to make a comparison on the line graph. It was found that maize crop was produced in the largest quantity within these years. The comparison in maize production in all the counties in Kenya was done on the line graph using yearly data from the ministry of agriculture, livestock and fisheries. Trans-Nzoia, Nandi, Uasin-Gishu, Narok, Bungoma, Nakuru, Kericho, Bomet, Kakamega and Vihiga were found to be among the highest maize producing counties in Kenya. The temperature, chemistry and flow rates for main geothermal fields in Kenya were obtained from the geothermal update reports. Eburru, Menengai and Olkaria geothermal fields were chosen as the key fields for because of their closeness to the maize producing areas. The maize drying requirements and technical analysis for maize was obtained from food processing and engineering literature. It was found that the best maize drying conditions were 43? temperature and 55.5% equilibrium relative humidity. The design of geothermal maize drying system was designed using maize drying requirements obtained from literature and climatic conditions of Nakuru area where the key geothermal fields were selected. In the design, the approximate amount of geothermal fluid required to dry a batch of 35 tonnes of maize per batch was obtained. The economic analysis for this sample dryer was done to determine the viability of the project. The net present value was found to be $82784, simple payback period was 5years, 1 months and 1 day and the internal rate of return 18% were the decision making tools used in determinations of the economic feasibility of the project.