Analysis of Biomasses for their Thermochemical Transformations to Biofuels

Abstract

Biomasses in the forms of agricultural and forestry residues are gaining attention as alternative sources of energy due to various limitations of conventional sources of energy. Their applications as energy sources should be renewable and eco-friendly. The selection of biomass needs pairing with a suitable thermochemical process for the generation of biofuels and their precursors. This article communicates the investigation of acacia nilotica branch, bagasse, berry branch, coconut coir, corn cob, cotton stalk, groundnut shell, rice husk, rice straw and wheat straw as biomasses, for their considerations to thermochemical transformations. The authors explored the residues for their bulk density, calorific values, proximate analysis, ultimate analysis, ash fusibility characteristics and thermogravimetric analysis. The bulk density and calorific values of materials considered were quite low compared to that of conventional solid fuels. Therefore, they required palletisation for their economical utilisation as feedstocks for thermochemical conversions to energy carriers. The proximate analysis indicated that the fixed carbon:volatile matter of acacia nilotica branch was highest at 0.35, suggesting it as the most preferred feedstock for pyrolysis. The ultimate analysis showed that H/C (molar element ratios) of all residues were near to a constant value indicating the emissions of volatiles/gases were close to same quality after their specific thermochemical transformation. Ash deformation and fusion temperatures of materials lied in the range of 900–1500°C, fixing the operating temperature limits for their transformations through combustors and gasifiers. Thermogravimetric analysis in the N2 atmosphere indicated that the rate of pyrolysis was highest for all residues, in the temperature range of 300–500°C, suggesting the sufficiency of one reactor to carry out pyrolysis for the individual biomass. Thus, the analysis of biomasses for their thermochemical transformations is the prerequisite for their effective utilisations.