Design and Experimental Investigation of an Electronics Spray Dryer Process Control

Abstract

Spray drying technology is an effective postharvest process for making fruit and vegetable powders with long shelf life. In general, spray dryer machine needs electricity energy for more than 5KW which can't be afforded by farmer community. In this study, low electricity energy spray drying machine was designed for farmer community. The machine use food grade stainless steel with the combination of electrical energy and liquid petroleum gas (LPG) energy. Electrical energy is used for electronics control system and air compressor, whereas LPG energy use for heat exchanger for the drying chamber. The electronics process controller is implemented to convert fresh fruit or vegetable into a fruit or vegetable powder form of a desired quality at a minimum cost. A simulation of a PID controller with Ziegler-Nichols tuning in the form of an Excel spreadsheet give the parameters used for the machine. Experiment was done to produce tomato powder from fresh tomato, whereas air inlet temperature of 150℃, the pressure of 3 bar and hot air outlet set to 100℃ with the addition of Maltodextrin 40mL/Liter has increase the powder quality, however adding more Maltodextrin make the tomato powder has less natural flavor. Increasing hot air temperature make the powder quality increase, in contrary the energy consumption of making the powder increased.