Increasing Heating value of Biochar using Pyrolysis of Alkaline Pretreated Rice Straw

Rice straw is a potential agriculture waste to produce biochar by pyrolysis process. The objective of this study is to investigate the physicochemical and energy properties of biochar from pyrolyzed rice straw. The rice straw was pyrolyzed at 300- 500 °C. In the pretreatment of rice straw, it was pre-treated with 1M sodium hydroxide and stirring for 1h. The highest bio char yield of 68.41 wt.% was obtained by pretreated rice straw at pyrolysis temperature of 300 °C. The proximate analysis was investigated including the moisture, volatile, fix carbon and ash content which were 0.85, 24.68, 60.2 and 14.27, respectively. The functional groups of biochar were characterized using FTIR spectrophotometer.  The energy content in term of high heating value of biochar and pretreated biochar was also investigated the fuel properties. The high heating value of the biochar increased from 12.16 MJ/kg to 27.23 MJ/kg in the pretreated biochar at 500 °C. The results suggested that the pretreated rice straw has a higher reaction of carbonization and decrease the ash content. The chemical energies of solid fuels are stored in fixed carbon and volatile matter. Consequently, this method can convert a great amount of rice straw waste to biofuel, it can also reduce amount of GHG from rice straw open burning.