CFD study on particle-to-fluid heat transfer in fixed bed reactors: Convective heat transfer at low and high pressure

• Published in: Chemical engineering science Vol. 61; no. 13; pp. 4341 - 4353
• Main Authors: Guardo, A., Coussirat, M., Recasens, F., Larrayoz, M.A., Escaler, X.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.07.2006; Elsevier
• Subjects: Applied sciences; Chemical engineering; Computational fluid dynamics; Exact sciences and technology; Fluid mechanics; Heat and mass transfer. Packings, plates; Heat transfer; Hydrodynamics; Packed bed; Reactors; Supercritical fluids; Fluid mechanics; Hydrodynamics; Packed bed; Supercritical fluids; Computational fluid dynamics; Heat transfer; Temperature distribution; Transport equation; Forced convection; Correlation; Carbon dioxide; Fixed bed reactor; Momentum; Supercritical state; Modeling; Design; Energy balance; Correlation analysis; Thermal fluid; Fixed bed
• ISSN: 0009-2509; 1873-4405
• DOI: 10.1016/j.ces.2006.02.011

Computational fluid dynamics (CFD) has proven to be a reliable tool for fixed bed reactor design, through the resolution of 3D transport equations for mass, momentum and energy balances. Solution of these equations allow to obtain velocity and temperature profiles within the reactor. The numerical results obtained allow estimating useful parameters applicable to equipment design. Particle-to-fluid heat transfer coefficient is of primal importance when analyzing the performance of a fixed bed reactor. To gain insight in this subject, numerical results using a modified commercial CFD solver are presented and particle-to-fluid heat transfer in fixed beds is analyzed. Two different configurations are studied: forced convection at low pressure (with air as circulating fluid) and mixed (i.e., free + forced ) convection at high pressure (with supercritical CO 2 as circulating fluid). In order to impose supercritical fluid properties to the model, modifications into the CFD code were introduced by means of user defined functions (UDF) and user defined equations (UDE). The obtained numerical data is compared to previously published data and a novel CFD-based correlation (for free, forced and mixed convection at high pressure) is presented.