Influence of microwave drying on the combustion characteristics of food waste

ABSTRACT

To study the influences of microwave drying on the combustion characteristics of food waste, this study conducted thermogravimetric analysis of cooked rice and vegetable leaves dried using a microwave at four intensities. The results suggested that dried rice and vegetable leaves were both favorable fuels, with higher comprehensive combustion characteristic indices than that of other biomass types such as straw, sawdust, etc. Microwave drying improved the combustion performance of food waste. The more intensive the microwave drying, the better the combustion performance of the food waste. Microwave drying significantly enhanced the combustion property of the selected vegetable leaves, while it exerted a slight influence on that of cooked rice. After microwave drying at 1500 W, the combustion characteristic index of vegetable leaves was increased by 34.47% compared with electrically dried samples. However, the combustion characteristic index of rice merely showed an improvement of 8.12%. Analysis of the combustion kinetics of food waste using the Coats–Redfern equation revealed that microwave drying changed the combustion kinetics of food waste. That is to say, the combustion rate of the food waste was accelerated by reducing the activation energy at low temperatures and increasing the activation energy at high temperatures.

KEYWORDS:

• Combustion characteristic
• combustion kinetic
• food waste
• microwave drying