Maize grain forced-convection mechanical drying process optimization: a case of Concession depot of company X in Zimbabwe

Abstract

Grain drying is a process that succeeds harvesting and is performed to sustainably maintain the properties of grain during the storage period. Elevated moisture content in grains shortens their shelf life, as it promotes bacterial growth. In this present research, the maize grain mechanical drying process parameters; drying air temperature (30 ºC, 60 ºC, and 110ºC), airflow rate (1.2 m/s, 1.5 m/s and 1.8 m/s), and drying time (30 min,120 min, and 180 min); were investigated and optimized as regards their effect on the on the dried grain quality and moisture reduction process to minimize the desiccating energy consumption. A full factorial design of experiment was planned, and optimization was carried out utilizing statistical tools, including analysis of variance and the main effects plot signal-to-noise ratio. Results revealed that the evaluated dehydration process parameters, air temperature, and air flow rate, significantly influenced the drying dynamics, whilst the time parameter displayed minimal impact on the process. The optimum drying process parameters were established to be 30 ºC drying temperature, 1.5 m/s airflow rate, and 120 min drying process run time. The percentage error margin between the predicted and confirmation experimental run results at the optimum parameter setting condition was less than 15%.