【摘要】 整体式催化剂能够解决纳米级催化剂在固定床加氢反应器中应用的缺陷,并进一步提高催化剂的催化性能。采用多次浸涂法制备了以Pd基蛋壳型SiO2纳米催化剂为涂层,铝溶胶为无机粘合剂、堇青石为结构化基体的整体式催化剂,并进一步研究了该整体式催化剂对乙炔选择性加氢反应的催化性能。研究结果表明:该整体式催化剂具有较高的比表面积和宏观的孔道结构,提高了活性组分的分散性并降低了气体的扩散阻力,在乙炔转化率接近100%时,乙烯选择性可以达到47.5%;此外,该催化剂良好的机械稳定性能,提高了催化加氢性能的稳定性。更多还原

【Abstract】 Monolithic supports can improve the performance of nano-catalysts by overcoming the problems which arise when they are used in a fixed bed reactor. A novel monolithic catalyst has been prepared by coating a Pd-loaded nano-catalyst on monolithic cordierite substrates through a dip-coating procedure with alumina sol as the inorganic adhesive. The nano-catalyst was formed in advance by an impregnation method with porous hollow silica nanoparticles (PHSNs) as support. Therefore,the resulting monolithic catalyst will have the advantages of both high surface area due to the coating of nanoparticles,and excellent mechanical properties inherited from the monolithic cordierite substrate. The high specific surface area of the support increased the dispersion of active components,and the macroporous structure reduced resistance to feed diffusion. The monolithic catalyst was evaluated for the selective hydrogenation of acetylene in a fixed-bed micro-reactor apparatus,and the results indicated that the monolithic catalyst possessed higher selectivity for ethylene than the nano-catalyst alone,and higher conversion of acetylene than over the monolithic catalyst without the nano-catalyst washcoat. The ethylene selectivity for the novel monolithic catalyst was as high as 47.5% when the conversion of acetylene was close to 100%,which is significantly superior to current commercial catalysts.更多还原