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.

Automated summary

The study found that optimizing operating conditions such as biomass particle size and heating rate can maximize bio-oil yield. Physicochemical properties of bio-oil samples were evaluated with a focus on analyzing chemical constituents using GC-MS and FTIR analysis. Biochar was also examined through various techniques to understand pyrolysis mechanism and practical applications.