Pressure drop and liquid hold-up in multiphase monolithic reactor with different distributors

Total pressure drop and liquid hold-up in two different monolith packings have been investigated experimentally in the co-current downward flow mode with a reactor diameter of 0.1 m and 0.6 m high monolith packing operating in the Taylor flow regime. The effect of distributor design on the flow distribution was investigated using two different types of distributor (nozzle distributor and packed bed distributor with 1 mm glass beads). A close relation of the distributor design to the hydrodynamics in monolith beds was observed to exist, evidenced by the larger pressure drop and liquid hold-up values for the monolith packings with an accompanying use of the packed bed distributor, as compared with the use of the nozzle distributor. An explanation for this phenomenon is the better gas and liquid distribution capability the packed bed has. By taking account of the effect of the liquid slug lengths, correlations were derived for predicting the two-phase friction factor and liquid hold-up and satisfactorily describe the experimental data. Finally an analysis of the unstable flow phenomenon characterized by negative pressure drops within bed shows that the unstable region is not only dependent on the operating conditions and properties of monolith but also on the distributor design.