整体式床层中液体分布与气-液传质的关系

With a particular focus on the connection between liquid flow distribution and gas-liquid mass transfer in monolithic beds in the Taylor flow regime, hydrodynamic and gas-liquid mass transfer experiments were carried out in a column with a monolithic bed of cell density of 50 cpsi with two different distributors (nozzle and packed bed distributors). Liquid saturation in individual channels was measured by using self-made micro-conductivity probes. A mal-distribution factor was used to evaluate uniform degree of phase distribution in monoliths. Overall bed pressure drop and mass transfer coefficients were measured. For liquid flow distribution and gas-liquid mass transfer, it is found that the superficial liquid velocity is a crucial factor and the packed bed distributor is better than the nozzle distributor. A semi-theoretical analysis using single channel models shows that the packed bed distributor always yields shorter and uniformly distributed liquid slugs compared to the nozzle distributor, which in turn ensures a better mass transfer performance. A bed scale mass transfer model is proposed by employing the single channel models in individual channels and incorporating effects of non-uniform liquid distribution along the bed cross-section. The model predicts the overall gas-liquid mass transfer coefficient with a relative error within ±30%.     

Cs/MgAl-LDO@X催化剂制备及甲苯侧链烷基化反应性能研究

以X分子筛为载体，在其表面上生长MgAl-LDH层状氢氧化物，浸渍Cs后焙烧，制备一系列Cs/MgAl-LDO@X催化剂。采用XRD、SEM、TPD等对催化剂的结构进行表征，并对甲苯侧链烷基化反应性能进行评价。表征发现，MgAl-LDO呈层状生长在X分子筛表面，随着生长量增多，层厚度逐渐增大，浸渍Cs后酸量和酸强度降低，碱强度增加。通过性能测试确定最佳Mg与Al比和MgAl-LDO生长量，此条件下甲苯转化率为4.33%,苯乙烯选择性为60.07%。     

Cs/CoAl-LDO@X催化剂制备及甲苯侧链烷基化反应性能研究

以X分子筛为载体，在其表面生长CoAl-LDH层状氢氧化物，浸渍Cs后焙烧，制备得到一系列不同CoAl-LDO含量的Cs/CoAl-LDO@X催化剂。利用XRD、SEM、TPD表征催化剂的结构、形貌及酸碱性质，在固定床微反应器上评价催化剂的甲苯侧链甲醇烷基化一步制苯乙烯的反应性能，研究不同CoAl-LDO含量对催化性能的影响。结果表明，随着CoAl-LDO含量的增加，催化剂的酸、碱活性中心的量有一定的增加；不同CoAl-LDO含量的催化剂对甲苯侧链烷基化反应都具有良好的催化性能。在最优反应条件下，甲苯转化率2.55%,苯乙烯选择性41.61%,苯乙烯和乙苯的总选择性可达92.51%。