负载PtSn金属助剂的镁铝水滑石上的丙烷脱氢反应研究

我们研究了以镁铝水滑石作为载体,利用水滑石层间阴离子的可交换性,负载活性金属铂和锡的丙烷脱氢反应.在镁铝水滑石载体中加入Ga能够影响丙烷脱氢活性,当镓的含量为1%时催化剂丙烷脱氢反应活性最高,反应初始时,丙烷转化率为46.5%,反应2 h后,丙烷转化率仍有37.5%.当以Mg(Ga)(Al)O-1%为载体时,考察了不同H_2/C_3H_8摩尔比对丙烷脱氢活性的影响,结果表明当H_2/C_3H_8摩尔比为0.5∶1时,丙烷脱氢反应具有最佳的反应活性,即当在原料气中加入H_2时,能够使得丙烷脱氢的转化率大幅度提升,且选择性也有所提升.烷烃脱氢是一个吸热反应,同时考察了温度对烷烃脱氢反应性能影响,结果表明温度越高,丙烷脱氢反应具有更高的转化率.对催化剂进行长时间寿命实验考察,发现当反应经过40 h后,丙烷的转化率仍有23.5%,说明Pt Sn-Mg(Ga)(Al)O-1%催化剂具有较好的稳定性.

The Performance of Propane Dehydrogenation over PtSn Metal Loaded on Calcined Mg-Al Layered Double Hydrotalcite

Magnesium aluminum layered double hydrotalcite (LDHs) are layered solids containing positively charged layers and exchangeable interlayered negative charge. Using the properties of exchangeability of LDHs, this paper study the performance of propane dehydrogenation reaction over calcined magnesium aluminum layered double hydrotalcite (LDHs) support where platinum and tin loaded by ion exchange method. Addition of Ga in magnesium aluminum hydrotalcite supports can affect the activity of propane dehydrogenation. When the content of gallium was 1%, propane dehydrogenation shows best the activity, the initial propane conversion is 46.5%, and still 37.5% after 2 h. The different H₂/C₃H₈ molar ratio also affect the activity of propane dehydrogenation. The results show that propane dehydrogenation reaction has the best activity when the H₂/C₃H₈ mole ratio is 0.5:1. The addition of H₂ in the feed gas can enhance the selectivity of propylene. Alkanes dehydrogenation is an endothermic reaction, thus the temperature also affect the activities of alkane dehydrogenation reaction. The results show that the higher the temperature have the higher conversion of propane dehydrogenation reaction. Stability tests show that the propane conversion has still 23.5% after 40 hours, indicating that the catalyst has a good stability.