A comparative study on pyrolysis kinetics and thermodynamic parameters of little millet and sunflower stems biomass using thermogravimetric analysis.

Several biochemical and thermochemical routes including pyrolysis, liquefaction, combustion and gasification are used to convert biomass to several bioproducts and green fuels. The current investigation included two important biomass namely, little millet stem (LMS) and sunflower stem (SS), whose potentiality as useful feedstocks is largely unexplored. The presence of considerable level of cellulose accumulation (approx. 30 %), volatiles (approx. 67 %) and high heating value (approx. 14 MJ/kg) in both the biomass, inferred their potentiality to be used as feedstocks in the pyrolysis process. The estimate of activation energy for LMS was reported as 191.14 kJ/mol (FWO), 191.46 kJ/mol (KAS) whereas for SS, the activation energy was estimated as 166.52 kJ/mol (FWO) and 162.68 kJ/mol (KAS). The difference between change in enthalpy and activation energy was small (5 to 6 kJ/mol) for both the biomasses, indicating the feasibility of combustion process. From Z(α) analyses, the experimental curve was seen passing through different theoretical curves, indicating complex nature of pyrolysis process for both the biomass.