Effect of magnesium addition on catalytic performance of PtSnK/γ-Al2O3 catalyst for isobutane dehydrogenation

The effect of magnesium addition on the catalytic properties of PtSnK/γ-Al₂O₃ catalyst for isobutane dehydrogenation has been investigated by reaction tests and some physicochemical characterizations such as nitrogen adsorption, TEM, H₂ chemisorption, TPR, H₂-TPD, and TPO. It was found that with the suitable addition of magnesium (0.2 and 0.4 wt.%), the platinum dispersion increased, while the carbon depositions decreased. The presence of Mg in the PtSnMgK/γ-Al₂O₃ catalysts could not only strengthen the Sn-Al₂O₃ interaction, but also stabilize the oxidation states of Sn species, which resulted in the increased reaction activity and stability. However, when the content of magnesium was excessive (0.6 and 0.8 wt.%), the character of platinum and the interfacial properties between the metal and the support changed evidently, which was disadvantageous to the reaction. In our experiments, addition of 0.4 wt.% Mg to PtSnK/Al₂O₃ catalyst showed the best catalytic performance. After reaction for 6 h, selectivity toward isobutene of higher than 94% was achieved with the corresponding conversion value of about 29.0%.     

开发对辊冷压造粒技术发展碳铵复肥

把碳铵加工成复肥,是小氮肥厂调整产品结构的一种选择。对各种复肥造粒工艺进行比较后作者认为,地辊设备生产碳铵复肥工艺合理,效果显著。