Pyrolysis of hyphaene thebaica shell over ceramic tile dust-derived catalysts and assessment of the produced bio-oil

• Published in: Waste Management Bulletin 2024-12, Vol.2 (4), p.64-75
• Main Authors: Mohammed, Habu Iyodo, Garba, Kabir, Ahmed, Saeed I., Abubakar, Lawan G.
• Format: Article
• Language: English
• Subjects: Bio-oil; Catalysts; Coking; Hyphaene thebaica shell; Pyrolysis; ZSM-5 zeolite
• ISSN: 2949-7507; 2949-7507
• DOI: 10.1016/j.wmb.2024.08.009

•ZSM-5 zeolite with hierarchical mesopores was synthesised from ceramic tile dust.•Biomass pyrolysis with the ZSM-5 and its metal oxide composites was performed.•The catalytic pyrolysis enhanced the fuel quality of the pyrolysis bio-oils.•Phenolic compounds, hydrocarbons, and esters were increased in the bio-oils.•The extent of coking on the ZSM-5 and its composites was established. The purpose of this study is to demonstrate the potential of ceramic tile dust (CTD)-derived ZSM-5 zeolite (CZ) and its monodispersed composite with metal oxides (MgO and Fe2O3) in the catalytic pyrolysis of hyphaene thebaica shell (HTS). The HTS was pyrolysed in a Fixed-bed reactor at 400–600 °C, and 100–300 mL/min N2 flowrate. The maximum bio-oil production of 32 % was obtained at 500 °C and 150 mL/min N2 flowrate, with bio-oils containing 50 % acid and octadecenoic acids, as well as esters, phenols, aldehydes, ketones, ethers, aromatics, and hydrocarbons. A carboxymethyl cellulose templating agent was employed for the mesoporous zeolite synthesis from CTD. This resulted in the mesoporous zeolite with a predominant ZSM-5 crystal phase, exhibiting pore diameters ranging from 1.8-6 nm, 229 m2/g surface area and 1145 μmol/g total acidity. The catalytic pyrolysis of HTS was conducted using the ZSM-5 zeolite (CZ) and metal-oxide (MgO, Fe2O3, and Fe2O3/FeO) modified CZ, as monodispersed composite catalysts. Under best thermal pyrolysis conditions, CZ-Fe2O3, CZ-MgO, and CZ-Fe2O3/MgO demonstrated 22–23 % bio-oil yields. Notably, the CZ-Fe2O3/MgO catalyst exhibited the highest hydrocarbon yield at 16 %, while the CZ-MgO favoured the production of phenolics, esters, and alcohols. CZ-MgO also displayed the highest coking level at 7.5 %, indicating faster deactivation than the other catalysts. The synthesised catalysts exhibited remarkable catalytic activity, resulting in a notable improvement in the quality of bio-oils obtained from the intermediate pyrolysis of hyphaene thebaica shells in a fixed-bed reactor.