Carbonization of Oil Palm Empty Fruit Bunches in a Fixed-Bed Pyrolysis Reactor for Community Use

Abstract

Biochar and wood vinegar are the main useful products from the carbonization process. The slow pyrolysis process is considered appropriate and should be promoted to farmers or community use in various applications, including household charcoal and wood vinegar production. This work aimed to design and construct a thermal reactor suitable for high yields and quality of biochar with wood vinegar produced for community use. In this preliminary work, a laboratory pyrolysis reactor equipped with a 5-kW electric heater and nitrogen as the carrier gas was used. Oil palm empty fruit bunches were considered. The research objective was to identify the optimum temperature and residence time for biomass pyrolysis used for the subsequent design and construction of the community pyrolyzer. The reaction temperature and time were tested in a range of 300-600 C and 60-180 min, respectively. In the carbonization process, the optimum temperature and residence time for oil palm empty fruit bunches were 400°C and 120 min, respectively. Increasing temperature and residence time resulted in reduced moisture and volatile, and increased fixed carbon contents. Maximum biochar yields were 30-35%, and the rest were wood vinegar, pyrolysis liquid and gas. At this optimum condition, the design for the community reactor should have a dimension of 1.5 × 1.5 × 1.2 m3 for width × length × height, with the design chamber volume 1.78 m3 and biomass loading capacity of more than 300 kg/batch.