Continuous microwave drying of the seeds of the invasive Chinese tallow tree

The Chinese tallow tree ( CTT ) ( Triadica sebifera ) is an invasive species in the Southeastern portion of the USA . With lipid content between 40% and 55%, the tree's non‐edible seeds are a valuable source for biofuel production. In situ transesterification is a proposed method for optimizing the transesterification process since it does not require prior oil extraction; however, for yields greater than 98%, the moisture content of the seeds should be less than 2%. In this paper we highlight an innovative microwave assisted drying method, used for the first time for these seeds, as a solution which drastically reduces the drying time and energy consumption compared to other drying methods. To optimize the microwave‐assisted drying of CTT seeds, temperatures of 25 and 55 °C were tested with microwave powers of 0, 200, and 600 W using a continuous microwave drying system. The decrease in moisture content is greatest at 600 W of microwave power, with ambient temperature having little effect on the heat generation. The drying rate to power consumption ratio is greatest with a combination of 600 W at 25 °C ambient temperature. The microwave assisted drying reduced the drying time to about 300 seconds compared to the 4 h required for conventional oven drying. © 2015 Society of Chemical Industry and John Wiley & Sons, Ltd