Intermediate Pyrolysis of Bambara Groundnut Shell (BGS) in Various Inert Gases (N2, CO2, and N2/CO2)

Abstract

Energy from biomass is increasingly gaining attention amidst the environmental challenges of coal and fossil fuels. This study investigated the effects of inert gases (N2, CO2, and N2/CO2) on intermediate pyrolysis and product properties from Bambara Groundnut Shells (BGS) (shells from an underutilized crop, which has high nutritional values). N2/CO2 atmosphere roughly represents flue gas. The results showed that the inert gases did not significantly affect the yields of bio-oil, biochar, and syngas. The pH of bio-oil ranged from 5.2–5.8, indicating the minimum presence of acids in bio-oil. The CHNS analysis showed that all bio-oil and biochar had their carbon content within 50.04–60.49 wt.%. The FESEM resulted in a wide range of pore sizes in biochar produced in an N2/CO2 atmosphere. The GC-MS (Gas Chromatography-Mass Spectrometry) analysis revealed the presence of compounds which can be categorized as alkene, acid, benzene derivatives, ketone, phenol derivatives, alcohol, aldehyde, alkyl, and ester. However, the presence of N2/CO2 gas favored alcohol and phenol production significantly.