Upgrading waste plastic derived pyrolysis gas via chemical looping cracking–gasification using Ni–Fe–Al redox catalysts

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Switzerland : 1996), 2022-06, Vol.438, p.135580, Article 135580
• Main Authors: Huang, Jijiang, Veksha, Andrei, Foo Jin Jun, Thaddeus, Lisak, Grzegorz
• Format: Article
• Language: English
• Subjects: Chemical looping; Coke formation; Metal–support interaction; Pyrolysis gas; Waste plastic
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2022.135580

[Display omitted] •Novel CLCG process is demonstrated to recover H2/syngas from plastic pyrolysis gas.•Ni–Fe–Al catalysts with varied Al/(Ni+Fe) ratios are prepared via coprecipitation.•High yields of H2 and syngas of 0.46 and 0.89 mol g(Ni+Fe)−1 are obtained on NiFeAl.•NiFeAl and NiFeAl10 show distinct effects on coke morphologies and activity. A novel chemical looping cracking–gasification process was investigated to produce separate H2 and syngas from plastic-derived pyrolysis gas over synthetic Ni–Fe–Al redox catalysts. The non-condensable pyrolysis gas was catalytically cracked at 800 °C, followed by catalyst regeneration with steam. The highest activity was obtained over NiFeAl (molar Ni:Fe:Al = 1:1:1), producing concentrated H2 (83.1 vol%, 0.46 mol g(Ni+Fe)−1) and coke intermediate (232.1 wt%) from cracking. During the steam gasification stage, coke removal efficiency of 96% was obtained with a high syngas yield of 0.89 mol g(Ni+Fe)−1. With equimolar Ni/Fe, increasing Al/(Ni+Fe) ratio led to decreased catalyst activity due to enhanced metal–support interaction. Plausible reaction mechanisms were proposed to interpret the catalytic effects on tuning the morphologies, chemical structure and activity of the coke deposits. This work demonstrates the important role of Ni–Fe–Al catalysts on the production of H2 and syngas via chemical looping cracking–gasification process.