(600bm) Optimization of Local Distributor for the Application in Monolithic Structures

In the following work a multi phase distributor was developed which is suitable for the application in monolithic structures. It is based on the injection principle which is often performed in single channel experiments to underline the concept of microchannels for gas-liquid-solid reactions. Therein the gas is injected into a channel by a needle. Below the gas entrance of the needle liquid flows around the needle and enters the channel. This is multiplied to get a distributor for multichannel geometries. Starting from this “injector scale-up” a new concept is created based on a modular structure with a needle matrix suitable for each cell density of the monolithic structure. First of all gas is injected through a module with two tangential inlets. Subsequently, a needle plate guides the gas into each channel. Below these two parts a liquid part divides the liquid between the needles and is guided in the channels directly. Due to the flexible design of the needle plate this concept can be adapted for the respective cell density of the monolith.

In the presented work the fundamental concept of this distributor was refined and optimized by using CFD. Several CFD studies have been processed to optimize each module with the aim of a homogeneous distribution of gas and liquid phase in the beginning of the monolith. Additionally, experimental work has been performed to validate the CFD simulation. By using a gravimetric method as well as a high speed tomography the simulation program was proved. Overall experiments were performed for liquid velocities starting from 0,018 m/s until 0,07 m/s for a 39 cpsi monolith. The gas velocity was varied from 0,1 m/s up to 3 m/s.

It was found that depending on the inlet geometry a more homogeneous phase distribution can be reached the more vortices you create within the distributor. But compared to a common full cone nozzle distributor a specific operating area for gas and liquid velocity exists to get an optimized distribution at the beginning of the catalytic structure.