Flow and heat transfer in narrow fixed beds with axial thermowells

Abstract

Axial thermowells are used to monitor temperature in lab scale and pilot plant fixed-bed catalytic reactor tubes. Particle-resolved fixed-bed computational fluid dynamics simulations are used to study the local changes in particle location, flow, and temperature that result from using thermowells in narrow packed tubes. The bed structure, velocity, and temperature were compared for randomly packed spheres in heated-wall tubes. Tube-to-particle diameter ratios 3.96, 5.96, and 7.99 were used, each with three different thermowell sizes and with no thermowell. The measured axial temperature profiles differ from those in the un-instrumented beds due to conduction and flow by-passing along the thermowells.