载体形貌对ZnO/SBA-15煤气脱硫剂结构及性能的影响

Effect of carrier morphology on structure and properties of ZnO/SBA-15 coal gas desulfurizer

通过控制合成条件,成功合成了不同形貌的介孔二氧化硅分子筛SBA-15。采用溶胶-凝胶法制备了SBA-15负载的氧化锌(ZnO)脱硫剂,并对其在模拟煤气气氛下脱除硫化氢(H_(2)S)的性能进行了评价。结果表明,当ZnO负载量为30%(质量分数)时,环状形貌SBA-15负载的锌基脱硫剂对H_(2)S的脱除效果最好、穿透硫容最高(5.65×10^(-2)g/g)。采用SEM、TEM和XRD等表征手段对样品进行了形貌和结构表征。通过关联脱硫剂的构效关系发现:载体较小的微观尺寸不仅有利于保持脱硫剂颗粒的结构稳定,而且有利于活性组分分散,从而增加H_(2)S与活性组分的接触机会;载体较大的总孔体积和平均孔径,有利于脱硫过程中的气体扩散和传质。

The mesoporous silica molecular sieves SBA-15 with different morphologies were successfully synthesized by controlling the synthesis conditions. The zinc oxide(ZnO) desulfurizer supported by SBA-15 was prepared by sol-gel method, and its performance of removing H_(2)S in simulated coal gas atmosphere was evaluated. The results show that when the ZnO loading capacity is 30%(mass fraction), the zinc-based desulfurizer supported by SBA-15 with doughnut-like morphology has the best H_(2)S removal effect and the highest sulfur penetration capacity(5.65×10^(-2)g/g). The morphology and structure of the samples were characterized by SEM, TEM and XRD. Through associating the structure-activity relationship of desulfurizers, it is found that the small size of the carrier is beneficial to keep the structure stability of the desulfurizer particles and disperse the active component, thus increasing the contact opportunity between hydrogen sulfide and the active component. The large total pore volume and average pore size of the carrier are conducive to gas diffusion and mass transfer in the desulfurization process.