Estudo hidrodinâmico computacional de reator UASB em escala de bancada com validação experimental

Abstract

The aim of this study was to evaluate the hydrodynamic behavior of a reactor (UASB) by computational fluid dynamics (CFD) and hydrodynamic tests of stimulus-response. Initially were simulated by computational fluid dynamics (CFD), the entry conditions of a pilot-scale UASB reactor of 160. Other computer simulations were performed on a bench-scale UASB reactor constructed of Plexiglass with 18 L, in order to observe the hydrodynamic behavior of the reactor operating with the injection of air into its base representing the gas generation of biological treatment process, and also the reactor operating with filling out 35% of its useful volume with a water absorbent polymer representing the characteristics of anaerobic sludge. The computational model used for simulation of bench-scale reactor was validated by comparing the volume of dead zones obtained by means of simulations with the values calculated in stimulus-response tests with eosin Y as tracer, the amount of dead zones calculated through the stimulusresponse tests presented an error of approximately 63% compared to value obtained with the computational model of reactor with the representation of anaerobic sludge that showed a bad correlation between the computational model. Experimental tests for this operating condition of the reactor showed a trend of hydrodynamic plug flow. For the operating condition of the reactor with air injection, the flow was more dispersed and the relative error between the simulated value in CFD and the experiment was 40%, representing a satisfactory correlation between the values, validating the simulation results.