A study of tea leaves drying using dehumidification process and regeneration of liquid desiccant in a closed-cycle dehumidification-humidification

¹ Department of Mechanical Engineering, Faculty of Engineering, Diponegoro University, 50275 Semarang, Indonesia
² Department of Industrial Technology, Faculty of Engineering, Diponegoro University, 50275 Semarang, Indonesia
³ Department of Mechanical Engineering, Faculty of Engineering, Islamic 45 University, 17113 Bekasi, Indonesia

^* Corresponding author: efnan2003@gmail.com

Abstract

Tea plants in Indonesia are derived from Carmelia sinensis var. assamica which contain catechin in quite high amount compared with other countries tea plant. Green tea is made by inactivating the oxidase / phenolase enzyme that presents in the fresh tea leaf buds from tea garden, by using hot steam to prevent the oxidation of the catechins. Drying process to reduce the moisture of tea, one of the method is by utilizing the dry air from dehumidification process. Liquid desiccant made from 50% concentration of CaCl₂, the temperature is lowered to 10 °C and sprayed into the air stream which contains water vapor by using a 0.2 mm spraying nozzle so that mass transfer and latent heat occur in the dehumidifier. The result of air dehumidification process used for drying tea leaves. The air is able to dry the tea leaves from the weight of 58 grams to 47 grams. Then the liquid desiccant dehumidification process will be streamed into the humidifier, where the liquid desiccant regeneration process will have change into the initial concentration. The result of air humidification process has an average absolute humidity rise of 0.07 g/kg. The liquid desiccant regeneration process that happened continuously reaching the saturation point at 280 minutes. It can be concluded that the process of dehumidification-humidification is a fairly effective method for drying the tea leaves.