Effect of temperature on the biochar properties from corn cob wastes

Abstract

Slow pyrolysis can convert biomass wastes into solid carbon-rich biochar. Fixed-bed slow pyrolysis experiments of corn cob were conducted to determine the effect of pyrolysis temperature on the properties of biochar. The pyrolysis temperature was varied from 200°C to 700°C. The heating rate was set at 5°C min-1 while the holding time was fixed at 1 hour. The characteristics of the biochar produced were investigated via proximate analysis and ultimate analysis. The results of slow pyrolysis experiments showed the decrement of biochar yield from 93.56 wt% to 24.59 wt% as the temperature increased from 200°C to 700°C. From the ultimate analysis of corn cob biochar, it was found that the percentage of fixed carbon content increased from 27.57 mf wt% to 93.65 mf wt% when the temperature increased from 200°C to 700°C. Corn cob biochar which was produced at 700°C contained the highest carbon content of 81.44 mf wt%. The percentage of hydrogen, nitrogen, sulfur and oxygen composition were at their lowest value of 2.54 mf wt%, 0.24 mf wt%, 0.21 mf wt% and 15.57 mf wt%, respectively. Pyrolysis temperature of 700°C produced high quality biochar with highest fixed carbon content of 93.65 mf wt% which was about 2.5 to 8.4 times higher than its raw feedstock value of 11.19 mf wt%.