Axial Mixing in Monolith Reactors: Effect of Liquid Distributor

Axial mixing is an important factor which affects gas and liquid (G-L) mass transfer in monolith channels significantly and therefore monolith reactors’ design and operation. Monolith reactor bed consists of a great number of straight channels in parallel which are separated by very thin walls. Due to the special structure, G-L distribution is formed at the monolith entrance and keeps the distribution into channels through whole bed height without G-L redistribution. So the effect of liquid distributor on G-L distribution is critical to axial mixing in monolith bed. In the present work the axial-mixing behanvior of the liquid phase in cocurrent down flow under the two types of liquid distributors (nozzle and glass beads distributor), square channel monoliths of different sizes (100 and 400 cells per square inch or cpsi) has been studied by analyzing the residence time distribution (RTD) of the injected tracer pulse. Simultaneous pressure drop measurements were used to estimate the average liquid slug length. The results show liquid slug lengths under nozzle distributor were longer than those under glass beads distributor, and the liquid slug lengths were observed to decrease with increase in cpsi under both distributors; the degree of axial dispersion using nozzle as liquid distributor is less than that when using glass beads distributor.