Thermodynamic, spectroscopic, and molecular characterization of rice straw biomass for use as biofuel feedstock

Abstract

India is one of the leading producers of rice in the world. Gasification and pyrolysis are two thermochemical processes. In the gasification process, biomass is transformed into syngas, which serves as an energy source. This conversion occurs under high temperatures with a carefully regulated and restricted air supply. On the other hand, pyrolysis, which transpires at lower temperatures without the presence of air, generates pyrolysis oil as a by‐product. This oil can be further refined into liquid fuels. For the purpose of investigating the feasibility of biofuel production, the current study involved the characterization of rice straw biomass using various techniques such as thermogravimetry differential thermal analysis (TG/DTA), Fourier transform infrared (FTIR), carbon, hydrogen, nitrogen, sulphur and oxygen (CHNS/O), inductively coupled plasma optical emission spectroscopy (ICP‐OES), among others. These analytical methods were employed to assess the potential of rice straw biomass for the production of biofuels. The existence of a significant amount of cellulose (32.1%), volatiles (approximately 67.06%), and high heating value (HHV) (13.18 MJKg−1) in rice straw inferred their capability to be used as feedstocks in the production of biofuel. The activation energy of approximately 173.20 KJ/Mol (Flynn Wall Ozawa [FWO]) indicated the viability of the burning process. From master plot (Z(α)) analysis, the experimental curve was seen passing through different theoretical curves, indicating the complex nature of the pyrolysis process for rice straw.