Methane decomposition over Ni supported on palm oil fuel ash (Ni-POFA) catalyst

• Published in: Chemical engineering research & design Vol. 178; pp. 224 - 231
• Main Authors: Hanifa, Nurul Husna Elyana, Ismail, Mazni, Ideris, Asmida
• Format: Journal Article
• Language: English
• Published: Rugby Elsevier Ltd 01-02-2022; Elsevier Science Ltd
• Subjects: Ashes; Catalysts; Catalytic converters; Conversion; Decomposition reactions; Flow velocity; Fuels; GHSV; H2 production; Hydrogen production; Methane; Methane decomposition; Ni loading; Nickel; Palm oil; Palm oil fuel ash (POFA); Performance degradation; Reaction time; Vegetable oils; Velocity; H2 production; Palm oil fuel ash (POFA); GHSV; Methane decomposition; Ni loading
• ISSN: 0263-8762; 1744-3563
• DOI: 10.1016/j.cherd.2021.12.035

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•The catalytic performance of Ni-POFA catalyst for methane decomposition has been evaluated.•Increasing the Ni loading from 5 to 15 wt.% increased the Ni-POFA performance.•Catalyst degradation at 20 wt.% Ni loading was due to Ni agglomeration and large filamentous carbon.•Increasing the GHSV from 5000 to 7000 mL/g h increased the Ni-POFA performance.•Low performance at 15,000 and 25,000 mL/g h was due to short contact time between CH4 gas and Ni-POFA.
The performance of Ni supported on palm oil fuel ash (Ni-POFA) catalyst was evaluated for methane decomposition reaction. The effects of Ni loading (5, 10, 15 and 20 wt.%) and gas hourly space velocity (GHSV) (5000, 7000, 15,000 and 25,000 mL/g h) were investigated at 550 °C for 6 h. The results show that increasing the Ni loading from 5 to 15 wt.% increased the initial H2 yield. However, the highest Ni loading (20 wt.% Ni) resulted in the lowest CH4 conversion and H2 yield, which has been associated to Ni particles agglomeration and formation of large filamentous carbon. The increase of GHSV from 5000 to 7000 mL/g h increased the initial CH4 conversion and initial H2 yield. Nonetheless, the catalytic performance of Ni-POFA degraded rapidly at higher GHSVs (15,000 and 25,000 mL/g h). This has been linked to a shorter contact time between CH4 gas and the catalyst at higher CH4 flow rates. The current study proposes the 15 wt.% Ni and 7000 mL/g h as the optimum Ni loading and GHSV for Ni-POFA catalyst, respectively. Under these conditions, methane decomposition performed admirably at 87.0% initial CH4 conversion and 27.0% initial H2 yield. Under the same conditions, the highest stable value of H2 production was achieved at ∼2.0% over the 6-h reaction time.