【摘要】 将不同孔密度载体径向组合,形成中心区域孔密度高于边缘区域的变孔密度组合载体,以改善催化转化器载体流动分布.利用FLUENT软件并耦合CHEMKIN,基于Rh催化剂表面CO-O2详细反应机理模型,对径向变孔密度载体建立催化反应模型.发现变孔密度载体的流动分布情况和CO转化率优于原载体,62/140,孔/cm2(每平方厘米孔道数)变孔密度载体的均匀性指数可达0.96,并且在一定范围内几乎不随空速的改变而改变,且压力损失仅略有提高.变孔密度载体(62/140,孔/cm2)的起燃温度比原载体(62,孔/cm2)略低,具有较好的起燃特性.此外,进一步探讨了贵金属负载量对起燃温度下CO转化率的影响,发现增大贵金属负载量可改善催化剂起燃特性,且同时选用较高孔密度载体和较高贵金属负载量有利于进一步提高催化剂低温活性.更多还原

【Abstract】 Based on the detailed surface reaction mechanism for CO-O2reaction over rhodium,the FLUENT software was employed and coupled with CHEMKIN code to establish a catalytic reaction model of radially variable cell density monolith. Compared with the monolith with uniform cell density,the variable cell density monolith obtains better performance on flow distribution and CO conversion efficiency.Only slight increase was found in pressure loss along the monolithic reactor. The flow uniformity index of62/140 cpsc(cells per square centimeter)variable cell density monolith is 0.96,and it remains constant with increase of space velocity. The 62/140 cpsc monolith achieves lower light-off temperature than that of raw monolith(62 cpsc),and the light-off performance is improved. Furthermore,the influence of precious metal loading on CO conversion under light-off temperature was investigated. Results show that the light-off characteristic of the catalyst is improved with the increase of the precious metal loading,and low temperature activity is further enhanced by employing higher cell density monolith.更多还原