钡改性对Cr_2O_3/Al_2O_3催化剂异丁烷脱氢性能的影响

采用浸渍法制备了不同BaO负载量的Cr_2O_3/Al_2O_3催化剂,利用XRD、BET、NH3-TPD和O2-TPO等表征方法对钡改性前后的催化剂进行了分析;在反应温度560℃、反应压力0.1MPa、催化剂用量10mL、GHSV=400h-1的条件下,在固定床反应器上考察了其异丁烷脱氢反应的性能。结果表明,钡的引入影响了活性组分Cr2O3的分散,导致了催化剂比表面积的降低,但影响并不显著;钡的引入降低了催化剂表面的酸性、减少了反应过程中催化剂的积炭,改善了催化剂的选择性,提高了催化剂的稳定性。当BaO负载量为3%时,催化剂的性能最佳。

Influence of barium addition on the performance of Cr2O3/Al2O3 catalysts in isobutane dehydrogenation

Barium modified Cr₂O₃/Al₂O₃ catalysts were prepared by incipient impregnation. The catalysts were characterized by XRD, BET, NH₃-TPD and O₂-TPO and tested for isobutane dehydrogenation in a fixed-bed reactor at 560℃, 10 mL catalyst, pressure of 0.1 MPa, GHSV of 400 h^-1 and atmospheric pressure. The results showed that the addition of Ba leads to the aggregation of Cr₂O₃, but no significant influence on the structure of the catalysts is observed. The surface acidity of the catalysts is weakened by the addition of Ba, which thereby inhibits the side reactions of cracking and carbon formation while the isobutene selectivity and stability of catalysts are improved. The optimal catalytic performance can be obtained when BaO content is around 3%.