کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
39127 | 45807 | 2015 | 9 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Improved catalytic performance of CaO and CeO2 promoted Ni catalyst on gasifier bed material for tar removal from producer gas Improved catalytic performance of CaO and CeO2 promoted Ni catalyst on gasifier bed material for tar removal from producer gas](/preview/png/39127.png)
• NiO have strong interaction with both CaO and CeO2 in Ni-CaO-CeO2 catalysts.
• Synergy between CaO and CeO2 promoters enhances tar removal activity of Ni than either CaO or CeO2.
• The highest coke resistance was observed in 2.5%(Ni20Ca60Ce20) composition.
• Higher basicity at higher CaO loading in Ni-CaO-CeO2 promotes less coke formation.
A new catalytic material containing the mixture of Ni, CaO and CeO2 for catalyzing commercial gasifier bed material (Carbo HSP) was synthesized and characterized by XRD, TPR/TPO, TPD and SEM techniques. The catalyst performance for tar removal in simulated producer gas mixture via steam reforming was tested in a lab-scale fix-bed reactor at atmospheric pressure and over a temperature range from 600 to 800 °C. The combination of Ni-CaO-CeO2 had significantly higher activity for toluene removal as compared to Ni, Ni-CaO or Ni-CeO2 systems. At 700 °C, the optimum composition 2.5 wt.% (Ni20Ca60Ce20) displayed 68% and 52% conversions for C7H8 and C2H4 respectively, leading to the highest CO2 selectivity. This catalyst composition shows only 7% (from 100% to 93%) deactivation in activity after 48 h in time-on-stream at 800 °C. After regeneration with an O2/H2 sequence, the conversion recovers to 100% and decreased only to 95% after 48 h in time-on-stream. Ni activity and stability are enhanced from the individual roles of CaO and CeO2. The CeO2 can act as redox component that provides for a higher H2O dissociation leading to carbon oxidation and the CaO can enhance the basicity of the catalyst as well as provide for a higher dispersion of Ni metal. The catalytic steam reforming of tars also results in a higher H2-to-CO ratio.
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Journal: Applied Catalysis A: General - Volume 498, 5 June 2015, Pages 150–158