Cleaner Potential for Natural Rubber Drying Process Using Microwave Technology Powered by Solar Energy

Abstract

To reduce carbon dioxide emissions from traditional drying methods, this research investigated the use of microwave technology for drying Standard Thai Rubber (STR) in Thailand. Commercial microwave ovens were modified and integrated with the microwave emitting power control system to maintain the appropriate temperature levels to evaporate the moisture from rubber. Throughout the drying process, the temperature of the rubber was measured both internally and outside. The results revealed that STR5L and STR20 could be dried satisfactorily and met the requirements for standard Thai rubber properties by utilizing 500 W for 140 and 120 min, respectively. By keeping the temperatures less than 150 °C, rubbers’ molecular structure is not destroyed from internal heat stress. Although utilizing less power for a longer period of time is possible, more energy was used, which is unfavorable. Compared to traditional hot air drying technologies, which take approximately 4–6 h for the drying process, microwave technology potentially reduces the drying time by half or more. If solar energy is used to supply electrical energy, 300,000 tons of Carbon dioxide can potentially be eliminated annually in the STR drying industry in Thailand by promoting approximately 1115 MW of Photovoltaic technology installations with the solar resources in southern Thailand.