Online estimation of tapioca starch moisture content in a flash dryer

In tapioca starch drying process, moisture content of tapioca starch is an important factor on the product quality. Normally, controlling starch moisture in drying is done by an operator resulting in a high variation of product moisture content. This research studied and developed a mathematical model for online estimation of starch moisture content in a flash dryer. Using a pilot-scale pneumatic conveying dryer with a drying tube of 9.7 m in length and an inner diameter of 0.07 m, a maximum of heater temperature of 350 °C, and an air velocity output of 15-20 m/s. In the dryer´s control system, moist starch feed rate, temperature and humidity of air could be measured while moisture content of starch could not be measured. The flash dryer model was implemented and was validated with experimental data. The inlet tapioca starch moisture content was estimated using the outlet air temperature and outlet air humidity. The inlet starch moisture content of estimation was examined in the model. The outlet starch moisture content was estimated. The mean absolute percentage error (MAPE) of the inlet starch moisture content by simulation and experimental data was 1.99%.