多相态条件下环己烷长时间连续脱氢反应研究

Investigation of the Continuous Dehydrogenation of Cyclohexane under Multiphase Reaction Conditions

对"湿-干"多相态条件下环己烷长时间连续脱氢反应进行了研究,考察了盐浴温度和环己烷进料速率对系统的产氢总量、环己烷脱氢速率和环己烷脱氢转化率的影响。结果表明,在无任何载气或吹扫气的条件下,环己烷在多相态条件下可以持续高效地进行脱氢反应,产生高纯度的氢气。在盐浴温度360℃,进料速率34 m L·h-1,催化剂用量3 g的反应条件下,脱氢系统的反应状态达到最佳,6 h的产氢总量为8.9 L,单位反应面积的平均产氢速率可达0.16mmol·min-1·cm-2。在"湿-干"多相态条件下,Raney-Ni在环己烷脱氢反应中表现出很高的催化活性,具有广泛的应用价值。对环己烷脱氢表观反应动力学的研究表明,脱氢反应的表观活化能较低,仅为12.54 k J·mol-1,多相态条件下环己烷的脱氢反应为扩散控制。

A six hour continuous dehydrogenation of cyclohexane was studied in this paper. The dehydrogenation was catalyzed by Raney-Ni under ＂wet-dry＂ multiphase reaction conditions. The influences of the salt bath temperature and feeding rate of cyclohexane on H2 evolution volume, He evolution rate and conversion of cyclohexane were investigated systematically. The experimental results show that, without assistance of any sweeping or carrier gas, high purity hydrogen can be obtained continuously through the dehydrogenation of cyclohexane. Under the conditions of the salt bath temperature at 360℃, feeding rate of 34 mL.h-1 and catalyst dosage of 3 g, the overall performance of the reaction system achieves its optimal. The calculated average hydrogen evolution rate per unit reaction surface area reaches 0.16 mmol.min-1.cm-2, which evidences that the reaction system proposed in this work is highly efficient. Raney-Ni shows excellent catalytic activity for dehydrogenation under ＂wet-dry＂ multiphase reaction conditions. Moreover, the kinetic study reveals that the apparent activation energy of the cyclohexane dehydrogenation reaction is 12.54 kJ.mol-1, which indicates that the reaction is strongly diffusion-limited.