Physicochemical analysis and intermediate pyrolysis of Bambara Groundnut Shell (BGS), Sweet Sorghum Stalk (SSS), and Shea Nutshell (SNS)

ABSTRACT

The current work focused on the intermediate pyrolysis of Bambara Groundnut Shells (BGS-G1), Sweet Sorghum Stalk (SSS), and Shea Nutshells (SNS). These feedstocks are readily available as wastes or by-products from industrial and agricultural activities. The thermo-gravimetric analysis of the biomass samples exhibited decomposition and devolatilization potentials in the temperature range of 110–650°C. The kinetic modelling resulted in the activation energy of BGS G1 being the lowest as 20.43 kJ/mol and SNS as the highest 24.89 kJ/mol among the three biomass samples. Intermediate pyrolysis was conducted in a vertical tube reactor at a temperature of 600°C, with nitrogen flow at 10 ml/min and heating rate ≥ 33.0℃/min. The yield of pyrolysis bio-oil was 38.0 ± 6.4, 44.2 ± 6, and 39.7 ± 5.2 wt.% for BGS-G1, SSS, and SNS, respectively. The HHV of bio-oil varied as 23.7 ± 1.8, 23.8 ± 1.8, to 26.5 ± 2.0 MJ/kg for BGS-G1 SSS and SNS respectively. The biochar recorded the lowest HHV for BGS-G1 as 18.8 ± 1.2 MJ/kg and the highest for SNS as 26.4 ± 1.8 MJ/kg. The FTIR of bio-oil revealed significant functional groups, and GC-MS (Gas Chromatography and Mass Spectrometry) analysis categorized the compounds in bio-oils as ketones, furans, phenolics, acids, phenols and benzene derivatives. The physicochemical analysis of the feedstocks and the products (bio-oil and biochar) showed their potential for bioenergy and biochemical (green chemicals) production.

GRAPHICAL ABSTRACT

KEYWORDS:

• Bambara groundnut shell
• Bio-oil production
• Intermediate pyrolysis
• Sweet sorghum stalk
• Shea nutshell

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The authors confirm that the data supporting the findings of this study are available within the article.

Correction Statement

This article has been corrected with minor changes. These changes do not impact the academic content of the article.

Additional information

Funding

This work was supported by Petroleum Technology Development Fund, Abuja, Nigeria [grant number PTDF/ED/OSS/PHD/POF/1323/17].