Desenvolvimento e implementação de um roteiro experimental para determinação do kLa em reatores tipo STR e coluna de bolhas.

Abstract

This study aimed to develop and implement an experimental protocol for determining the volumetric oxygen transfer coefficient (kLa) in Stirred Tank Reactors (STR) and bubble column reactors, with a focus on its application in the Transport Phenomena Laboratory. The research stemmed from the issue of limited practical experiments in the area of mass transfer, utilizing equipment already available in the laboratory to optimize resources. The methodology was based on the Dynamic Gassing-out method, which involves the removal of dissolved oxygen using nitrogen, followed by reoxygenation with air while monitoring the oxygen concentration over time. Different operating conditions were tested, such as variations in agitator speed (500, 750, and 1000 rpm) and air flow rate (2.0 to 10 L/min). The results showed that increasing both agitation speed and airflow significantly raised the kLa values, ranging from 0.0063 to 0.368 s⁻¹ in the STR and from 0.20 to 0.24 s⁻¹ in the bubble column, highlighting the greater efficiency of the STR due to mechanical agitation. It was concluded that the dynamic method is effective for determining kLa, and the developed protocol can be applied as both a didactic tool and a means for optimizing industrial processes. The study contributed to diversifying laboratory practices and emphasized the importance of controlling operational parameters in mass transfer.