Hydrodynamic Characteristics Study of Three Phase Trickle Bed Reactor

Abstract

Trickle bed reactors are the simplest three phase contacting devices employed in wide variety of fields such as fine chemicals, waste water treatment, food processing, petrochemicals, and petroleum industries. Their operation involves passing the gas and liquid phase reactants in downward direction along gravity over a solid packing. Most industrial trickle beds are used for hydro treating, hydrodesulphurization and oxidation operations. With wide range of applications, in depth understanding of working of the trickle bed reactor has become imperative to realize its full potential. The fundamental parameters which are used in the design and operation of trickle bed reactors are the dynamic liquid holdup and pressure drop. The pressure drop indicates the energy required to move the fluid through the column while dynamic liquid saturation indicates the efficiency of contacting between solid-liquid- gas phases. The present study has been carried out to investigate the pressure drop and dynamic liquid holdup of air-water system and air-CMC solution system. Air- CMC system has been selected to understand and quantify the effect of viscosity on pressure drop and dynamic liquid holdup. By varying the liquid and gas flow rates along with viscosity, the pressure drop and dynamic liquid saturation changes were studied. Results from pressure drop plots indicate increase in pressure drop with increase in liquid and gas flow rate, while dynamic liquid saturation decreases with increase in air flow rate. It was also observed that pressure drop and dynamic liquid holdup increased with increasing the viscosity of the liquid solution. The results provide the transition region between trickle and pulse flow regime. This region is very important because most of the trickle bed reactors used in various industries operate in this region.