Increase in charcoal yields of fast-growing trees

摘要

Fast-growing trees are widely cultivated in the north-eastern of Thailand. The residues of them are plentifully. The aim of this research was the increase in yield of charcoal during cool down process under nitrogen atmosphere. Two kinds of wood residues, eucalyptus and bur-flower, were used for investigation. Charcoal production was carbonized in a high temperature resistant cement furnace. The procedure for converting wood to charcoal was the heating rate of 60 °C/min and holding at the temperature of 550–600°C for 90 minutes. All of air inlet and outlet were closed to stop combustion reaction and the nitrogen gas was then fed into the furnace at the absolute pressures of 200, and 300 kPa during cool down charcoal over night. Yield percentage, proximate components, and heating value of charcoals were compared to charcoals from normal cool down process without nitrogen and traditional method. The results showed that both eucalyptus and bur-flower charcoals under nitrogen atmosphere at the absolute pressure of 200 kPa got the highest yield percentage. Under nitrogen atmosphere at this pressure, bur-flower wood obtained the charcoal yield higher than that eucalyptus wood. While bur-flower charcoal cooled down with nitrogen at the absolute pressure of 300 kPa and without nitrogen gas yielded the lower than that eucalyptus charcoal. When compared with charcoal of traditional method, only charcoal from normal cool down process without nitrogen produced the lower yield. In addition, the production of charcoal without nitrogen and with different nitrogen pressure and traditional method did not significantly affect on fixed carbon, volatile matter, moisture, ash contents, and heating value.