I. Introduction
Phthalic anhydride is widely used as a plasticizer for polyvinyl chloride and other plastics. It is also an important precursor for pharmaceutical drugs like cellulose acetate phthalate which helps fight viral diseases. Since PA synthesis is an exothermic process, mitigating the formation of hotspots to prevent catalyst deactivation and thermal runaway is of the highest priority due to safety concerns, and therefore, the need for high-fidelity models that accurately simulate transient and steady-state response of the reactor is evident. Previous researchers have used computational fluid dynamics (CFD) tools to create simulations for the fixed-bed catalytic reactor for synthesis of PA to study the relationship between product yield and the stability and activity of the catalyst. These simulations often use three-dimensional modeling, making them computationally expensive. It is the goal of this work to develop a two-dimensional in space CFD model of the fixed-bed catalytic reactor that will be both accurate and computationally affordable in a CFD software (i.e., ANSYS Fluent). This two-dimensional CFD model will represent a cross-section of the reactor along its axis and will account for the radial variation between the axis and the wall of the pipe (i.e., axisymmetric model). Because it is assumed that the reactor is symmetrical in the azimuthal direction, the two-dimensional plot can be rotated about the axial direction to generate a three-dimensional representation of the fixed-bed catalytic reactor. The decision to take advantage of the reactor symmetry in this way will allow for the generation of a computationally affordable two-dimensional simulation with the same output of meaningful data as a computationally expensive three-dimensional model. Improvements to the computational efficiency of fixed-bed catalytic reactor simulations will enable improvements to its operation and control, which will in-turn improve the consistency and safety of process plant operations.