CFD Simulation of Pressure Drop and Liquid Holdup in a Trickle Bed Reactor

Abstract

Trickle Bed Reactors have etched a ubiquitous presence in chemical processing sector. From petroleum and petrochemical products, fine chemicals to biochemical, wastewater treatment, they are almost everywhere. Products worth of 300 billion US $ are processed by these reactors on an annual average. A complete understanding of hydrodynamics, fluid phase mixing, interphase and interparticle heat and mass transfer and reaction kinetics of TBR can help us to extract the full potential of TBR. Studying the variation of pressure drop and liquid holdup is crucial for evaluation of performance of trickle bed reactors and can help in further optimizing their performance. This project focuses on the effect of gas and liquid velocities on the pressure drop and liquid holdup in a trickle-Bed reactor operating at ambient temperature and atmospheric pressure. Pressure drop and liquid holdup are two critical hydrodynamics parameters that influence other parameters directly and indirectly and hence, these two parameters are preferred for hydrodynamic study of TBR. Their variation along longitudinal and transverse direction is the focus of this project. A comparison of results from different simulation scenarios (using different pressure values as patching values) made in this project helps in understanding how different initial guess can affect the final solution in simulating real-life TBR operation. It is found that pressure ranging up to 10000 Pa as patching pressure value can lead to a converging solution. Afterwards, solution instability creeps in leading to impractically higher values of pressure and liquid holdup and sometimes ending up with divergence. Even the effect of gas and liquid velocity is studied on the two parameters. The variation of the two hydrodynamic parameters with changing liquid velocities and gas velocities are also studied. [math mode missing closing $]