A comparative study on valuable products: bio-oil, biochar, non-condensable gases from pyrolysis of agricultural residues

In this study, pyrolysis of agricultural residues, such as rice straw (RS), wheat straw (WS), and sugarcane bagasse (SB), was performed in a fixed-bed reactor. The experiments were carried out at varying operating conditions, such as temperature, heating rate, biomass particle size and sweeping gas flow rate, such that the bio-oil yield could be maximized. Small particle size and high heating rate contributed to more bio-oil yield as compared to large particle size and low heating rate. Physicochemical properties of bio-oil samples, evaluated in a comparative manner with maximum focus devoted on analyzing the chemical constituents through GC-MS and FTIR analysis. Biochar was also examined through different physicochemical techniques (e.g., HHV, pH, SEM-EDX, FTIR, CHNS, ICP-AES) for understanding pyrolysis mechanism and its practical usability. Analysis of non-condensable gas through GC-TCD, revealed co-existence of H-2, CO, CO(2)and CH(4)molecules, with greater percentage of H(2)and CH(4)at high temperature resulted enhancement in calorific value.