Ammonia synthesis over <i>γ</i> -Al <sub>2</sub> O <sub>3</sub> pellets in a packed-bed dielectric barrier discharge reactor
Xinbo Zhu, Xueli Hu, Xiqiang Wu, Yuxiang Cai, Hongbin Zhang, Xin Tu
Abstract
Abstract In this work, ammonia (NH 3 ) synthesis from N 2 and H 2 was carried out in a packed-bed dielectric barrier discharge (DBD) reactor, while three kinds of commercial packing materials including acidic γ -Al 2 O 3 , alkaline γ -Al 2 O 3 and neutral alumina pellets were employed. The effect of packing materials on plasma-assisted NH 3 synthesis was investigated and compared with an unpacked DBD reactor. The results show that the presence of packing materials enhanced the plasma-assisted NH 3 synthesis by 15.6% to 44.4% compared to the plasma reaction without a packing. The highest NH 3 concentration of 1565.5 ppm was obtained over the alkaline γ -Al 2 O 3 packed plasma reactor. The improvement of packing materials on plasma-assisted NH 3 synthesis followed the order of alkaline γ -Al 2 O 3 > neutral γ -Al 2 O 3 > acidic γ -Al 2 O 3 > blank tube only. A series of characterizations were performed to illustrate the structure-performance relationships between plasma-induced NH 3 synthesis process and packing materials. The results showed that the basicity of the packing materials played an important role in the plasma-assisted NH 3 synthesis process. The reaction mechanisms of NH 3 synthesis in the packed-bed DBD reactor were also discussed.