Hydrodynamic study of small-scale uasb reactor by computational fluid dynamics (cfd): simulation and validation

A small-scale UASB reactor was modeled in order to evaluate its hydrodynamic behavior and compare CFD simulations with experimental results obtained on a laboratory scale. Simulations using Ansys((R)) CFXTM were carried out with two different flow rates: A) 26.68 and B) 4.0 l d(-1). The reactor volume was 1.5 liters, with a useful volume of 1.38 liters. In addition to the CFD simulations, hydrodynamic tests with tracer injection were performed, both experimentally and in simulations. Residence time distribution (RTD) curves were obtained and the number of tanks-in-series (NTIS) model was used for determination of hydrodynamic behavior. The NTIS values calculated using CFD simulations were 5.55 and 4.76, for flow rates A and B, respectively. For the experimental analysis, the NTIS values were 6.67 and 5.54, for A and B flow rates, respectively. The Mann-Whitney U test was performed to confirm the similarity between CFD simulations and experimental tests. The results of the Mann-Whitney U test showed no statistically significant differences between the CFD simulations and experimental data. It can be concluded that CFD simulations are valid and can be used to analyze the hydrodynamic behavior of UASB reactors.