Intermittent drying and draft tube design for spouted bed

Abstract

The conventional spouted bed has presented several limitations that restrict the use on an industrial scale. Thus, studies of different methodologies and configurations have been performed to overcome such limitations. Limited processing capacity (scaling-up) and energy issues are some of the main problems considered from an industrial point of view. Alternatives as a heat recovery system lost in the exhaust air, intermittent drying, and draft tube can be promising and have not been explored in the spouted bed. Therefore, the main objective of this Ph.D. thesis is to design a spouted bed with a heat recovery system lost in the exhaust air, coupling the methodology of the intermittency and the use of the draft tube. Two types of intermittency (reduction and total interruption of the air flow) and five different intermittency profiles have been evaluated, including the use of time-variant intermittency ratios. Alumina, soybean, and barley have been used as particulate materials. Regarding the internal devices, three different configurations have been employed: without, nonporous, and open-sided. Based on particle image velocimetry (PTV), a new draft tube is designed for the equipment proposed, i.e., a spouted bed with a heat recovery system built according to the results obtained and the design criteria of our research group. Thus, the current Ph.D. thesis contributed to obtain energy-efficient equipment with suitable and feasible characteristics for industrial applications.