Pyrolysis of coconut shells in a concentric three tubes reactor

To improve energy efficiency, coconut shells were pyrolyzed in a concentric three tubes reactor using a combination of external and internal heating method. Coconut shells were oxidized partially at the bottom of the reactor, and the gas rised through the redhot charcoal packing to be cracked to smaller compounds and burnt by the air. The hot gas diverged outward and flowed down along the outside wall of the second tube before it left the reactor. The higher the temperature and the longer the time of pyrolysis, the less charcoal and light oil, but the more tar were produced. The charcoal obtained was in between that produced from external and internal heating procedures. Under the optimum time of 95 minutes and temperature of 579°C, the products were 19.53% charcoal, 5.22% tar, and 0.16 % light oil.