Study of drying technologies on a cellulose based material

Abstract

Bio foams have been recently proposed as an alternative to single use plastics in order to reduce their enviromental impact. A bottleneck on the production of bio foams has been identified in the drying process. In this study, multiple drying technologies, such as hot-air, air impingement, and infrared radiation, are tested on a cellulose based foam. Drying rates are calculated for each of the technologies tested at different temperature ranges. The resulting foam quality is also evaluated for each of the technologies. It is stablished that air impingement holds the highest drying rates with up to 18.6 kg of H2O per h per m2 at 290ºC. The lowest temperature tested with impingement, with a drying rate of 11.4 kg of H2O per h per m2 at 175ºC, is twice as high as the drying rate obtained with hot air and infrared. The foam quality obtained under hot-air and impingement drying was satisfactory, while the one subject to only infrared ranged from poor to acceptable. Based on theoretical background research a drying process combined the tested technologies is proposed. Additionally, it was found a shift on the foam properties when dried with air at high temperatures, which is likely to happened to the degradation of the methylcellulose.