Influence of viscosity on gas holdup formation in stirred tank reactors

The mechanically agitated vessels serving as gas–liquid stirred tank reactors are often utilized equipment in the chemical, biochemical, pharmaceutical, and food industry worldwide. When the gas flows through the stirred tank reactor, the liquid level in the tank increases. The amount of encaptured gas is usually expressed as a volumetric fraction of gas in dispersion (also called gas holdup). The gas holdup is one of the main characteristics in the case of gas–liquid contractors because it directly indicates the active interphase area. The most important factors affecting the gas holdup are: vessel and impeller geometry, operational conditions, and chemical properties of the examined system. This work focuses on the viscosity influence on gas holdup formation in laboratory and pilot plant stirred tank reactor at a wide range of experimental conditions. The influence of gas flow rate, impeller type, impeller diameter, batch viscosity, and other operational conditions was tested. The broad experimental conditions were used for establishing chemical engineering correlations that would be viable for the design and scale up.