Zr改性Ni/γ-Al2O3催化剂用于浆态相合成气的低温甲烷化

采用浆态床反应器,在低温(300~330 ℃)下进行合成气的甲烷化反应.实验中通过共浸渍法(包括含浸-旋蒸法)制备了锆(Zr)修饰的Ni/γ-Al₂O₃催化剂,并考察其与单一NiO、未掺杂Zr 的Ni/γ-Al₂O₃催化剂的催化性能差异.研究表明,载体γ-Al₂O₃的引入能够明显地提高CO的转化率和甲烷的选择性,而Zr的掺杂会进一步提升催化剂的催化活性.在325 ℃,空速为4 200 mL·g^-1·h^-1时,CO的转化率可以达到86.41%,甲烷选择性为90.53%.催化剂的表征结果表明,Zr的添加促进了Ni在催化剂表面的分散、减弱了活性Ni与载体的相互作用,抑制了低甲烷化活性的NiAl₂O₄的生成,使得催化剂的反应性能得到较大提高.

Low temperature methanation of syngas in a slurry reactor over Zr-doped Ni/γ-Al2O3 catalyst

Zr-doped Ni/γ-Al₂O₃ catalyst was prepared by co-impregnation of Ni and Zr on γ-Al₂O₃; over it, the methanation of syngas at low temperature (300~330 ℃) in a slurry reactor was investigated. Compared with single NiO and Ni/γ-Al₂O₃, the catalytic performance of the Zr-doped Ni/γ-Al₂O₃ is greatly improved. Under optimized condition, a high CO conversion of 86.41% and a selectivity of 90.53% to CH₄ are achieved at a GHSV of 4 200 mL·g^-1·h^-1. XRD, TEM and H₂-TPR results suggest that the doping of Zr promotes dispersion of Ni on γ-Al₂O₃, weakens the interaction between Ni and the support and suppresses the formation of NiAl₂O₄ spinel with low methanation activity; all these may contribute to the excellent performance of the Zr-doped Ni/γ-Al₂O₃ catalyst in syngas methanation.