Design of an automatic electric torrefaction reactor for oil palm empty fruit bunch pellets

Abstract

Abstract One of the technologies for utilizing waste into high-quality fuel is torrefaction. Torefaction of empty palm fruit bunches is a thermochemical process without the presence of oxygen by heating the biomass slowly and holding it for a certain time. Torrefaction degrades the hemicellulose content to optimize mass and energy yields. The purpose of this study was to design a temperature control system using a electrical heater on a rotary torrefaction reactor for Oil Palm Empty Fruit Bunch (OPEFB) pellets. The validation temperature sensor has shown a coefficient of determination (R2) 0.9999 using the model coefficient y = 1.0029x + 0.4017. The performance results of the electric reactor control system for torrefaction show a temperature control accuracy of 85.77% at various setting points. The response of the temperature control system within 10 minutes can reach a temperature of 213°C and in the 13th minute it reaches 301.6°C. The stability of the tool produces good performance. The electric power consumption for 6 kg OPEFB pellets was 2.98 kWh at a cost of USD 0.33. The water content in the torrefaction pellets is 1-2%. The results of the hydrophobicity test showed that the torrefactive samples at temperatures above 200 °C did not change their physical form after immersion in water for 24 hours. These results indicate that the electric torrefaction reactor automatic has succeeded in increasing the caloric ratio of the material, resistance to water such as charcoal, but still has the characteristics and properties of biomass.