Estimating energy requirement in cashew (Anacardium occidentale L.) nut processing operations

This work deals with a study on estimation of energy consumption in eight readily defined unit operations of cashew nut processing. Data for analysis were collected from nine cashew nut mills stratified into small, medium and large categories to represent different mechanization levels. Series of equations were developed to easily compute requirements of electricity, fuel and labour for each of the unit operations. The computation of energy use was done using spreadsheet program on Microsoft Excel. The results of application test of the equations show that the total energy intensity in the cashew nut mills varied between 0.21 and 1.161 MJ/kg. Electrical energy intensity varied between 0.0052 and 0.029 MJ/kg, while thermal energy intensity varied from 0.085 to 1.064 MJ/kg. The two identified energy intensive operations in cashew nut processing are cashew nut drying and cashew nut roasting, altogether accounting for over 85% of the total energy consumption in all the three mill categories. Thermal energy, obtained from diesel fuel, represented about 90% of the unit energy cost for cashew nut processing. The developed equations have therefore proven to be a useful tool for carrying out budgeting, forecasting energy requirements and planning plant expansion.