In every case it can be observed that

Table 2.
Product yields of slow pyrolysis of rice straw at different temperatures.Temperature, °CBio-oil, wt.%Bio-char, wt.%Gas, wt.%Conversion, %30029.239.231.660.835030.635.633.864.44003134.234.865.845029.833.23766.8Full-size tableTable optionsView in workspaceDownload as CSV
Between the temperatures of 400 and 450 °C, the yield of gas has increased thereby reducing the bio-oil yield since the bio-char yield 3X FLAG tag almost similar. The secondary reactions are supposed to have occurred thereby producing non-condensable gases. The decrease in the char yield with increasing temperature could either be due to greater primary decomposition of biomass at higher temperatures or through secondary decomposition of char residue (Pütün et al., 2005). It can be concluded that 400 °C is the optimum temperature for slow pyrolysis of rice straw giving high yields of desirable products namely the bio-oil and bio-char. The results are well in line with that observed in the open literature as the bio-oil yield is more in case of inert atmosphere than hydrogen atmosphere. This maybe due to the tendency to produce more vapours which re-polymerise into char in case of reductive gas presence (Thangalazhy-Gopakumar et al., 2011).