Performance Evaluation of a Small Scale Maize Grains Dryer

Ibrahim S. O, Fashina A. B., Akande F. B., Sanusi B. A.

Maize is a food material for both humans and animals and its production and preservation is therefore important so as to make it available and affordable throughout the year. The preservation of surplus crops including maize can be regarded as one of the first and most important processing technique. Maize is usually harvested with high moisture contents that make its storability difficult, to avert this maize dryer was developed and its performance evaluated.Freshly harvested maize [DMR –Yellow) collected from the agricultural engineering demonstration farm of the polytechnic, Ibadan, Saki Campus was used as test materials. In order to assess the performance of the dryer in form of uniformity in temperature distribution, temperature distribution test was conducted. Performance of the dryer was tested by introducingshelled maize of 35%(wb) initial moisture content into the dryer. Samples were collected from the dryer at an interval of 30 minutes until the drying time was 4.5 hours. Moisture contents of the samples collected were determined.  The results of temperaturedistribution tests showed that the dryer reaches an equilibrium state in terms of temperature distribution after the 15^th minute of operating the dryer irrespective of the set temperature and air velocity. The values of moisture contents decrease progressively from 34.70 to 13.57 % (wb) as the time increases from 0.0 to 4.5 h at 40 ^oC. It decreases from 34.70 to 13.35 % (wb) and from 34.70 to 12.23% (wb), at 45^oC and 50 ^oC, respectively, within the same time frame. There is a progressive decrease in moisture content of the maize grain as the drying time and air velocity increases for all the pre – set temperatures (40, 45 and 50 ^oC). It was further revealed that, the reduction in moisture content of the maize grain were faster at higher air velocities and air temperatures.