ABSTRACT

This study involves multiobjective modeling, optimization and investment analysis of an integrated milling-sieving-dewatering machine for extracting slurry food starch from soaked grains. This is to enable its optimal operation and mass production of quality slurry food diets at low cost. The effects of the operational parameters of this machine on its multipleperformance indicators were empirically evaluated, modeled and optimized using response surface based desirability optimization methodology while cost-benefit analysis constitutes the investment evaluation techniques applied.Performance analysis results revealed 30-70L/h, 10-40rpm, 0.45-0.9rpm and 55-90kPa as functional limits within which water feed rate, sieving shaft speed, dewatering drum speed and pump pressure influence this machine’s performance. In addition, its response model developed in this study for exhibited with over 98% prediction accuracies. The response models revealed that main and quadratic effects as well as some interactions of allthe factors of this machine affects its responses except the sieving speed which does not affect the moisture content of the extracted cake food starch. Moreover multiobjective optimization of the models also revealed optimal settings of this machine’s water feed rate, sieving shaft speed, dewatering drum speed and pump pressure as 70L/h, 10rpm, 0.59rpm and 90kPa respectively. The machine performs with throughput, extraction efficiency, cake moisture content and specific energy consumption respectively of 87Kg/h, 98.75%, 25.35% and 183kJ/Kg respectively at this optimal factor settings. Thereby improving throughput, extraction efficiency, cake moisture content and specific energy consumption of this machine by 23.51%, 0.27%, 19.64% and 19.13% respectively. The costbenefit analysis of this machine confirmed its positive capital recovery potentials with apayback period, benefit-cost ratio and annual rate of return of 1.86 years, 1.75 and 31.41% respectively at these optimal parameter settings. The payback of 1.86years is far less than 10 years useful life of the machine whileits 31.41% accounting rate of return outweighed Nigerian banks maximum fixed deposits return of 17% and prime lending rate of 29%. Thus, general adoption of the slurry food milling-sieving-dewatering machine is recommended for advancement of grain slurry food processing sector.