Open air drying of bagasse - potential in sugar industries (case study: mumias sugar company)

Abstract

Biomass feed stock like wood chippings, rice husks and sugarcane bagasse once considered waste are now looked upon as viable fuel sources. Bagasse, a byproduct of sugar cane crushing and leaching, is used in sugar industries to generate high pressure and temperature steam in the boilers for generating electricity which is then utilized internally in the factories and also exported to the grid. In most instances, the bagasse as used directly from the mills contains about 50% moisture as is the case in Mumias Sugar Company (MSC). However, for more efficient utilization, further drying through methods such as flue gas drying, exit steam drying and open air drying to lower its moisture content is useful in increasing its calorific value This study was done to assess the potential of open air drying of bagasse and the resulting improvements in its combustion. The main stages of the study included the design of the drier, determination of the calorific value of dried bagasse and the effect on combustion. Two dryers were fabricated for drying of bagasse. One had a steel cover and the other a glass cover The following parameters were monitored during drying , relative humidity (RH), temperature (T), Solar Insolation (W/m2) and moisture content (%). The results revealed that open air drying reduced the moisture content of bagasse by about 4% - 6% in 3-4 hours of drying in a day. The gross calorific value of the dried bagasse also increased considerably from 9514kJ/kg at 50% moisture content to 11343.7kJ/kg at 40.05% moisture and to 18103kJ/kg at 5.4% moisture content on the third day of continuous drying.