Gas holdup at dynamic equilibrium region of a bubble column: Effect of bubble generator performance

Gas holdup along with the superficial gas velocity was systematically investigated in a lab-scale bubble column. The experiments were conducted in a bubble column with a height of 6 m at superficial gas velocity of 0.01-0.13 m/s. Experimental results show that dynamic equilibrium region was achieved at a distance of 2800 mm above the bubble generator. Small initial bubble size will lead to higher gas holdup and slump trend. To overcome the trade-off between sufficient gas holdup and slump trend, a reasonable gas holdup without slump can be obtained by controlling the liquid mass flow in the nozzle. Based on previous empirical correlations and experiment data, a semi empirical correlation of gas holdup was established consider the flow regime transition and bubble generator performance. The semi empirical correlation in this work gives a fairly accurate prediction while several empirical coefficients were used.

Automated summary

This study systematically investigated the gas holdup and superficial gas velocity in a lab-scale bubble column. The experimental results showed that a dynamic equilibrium region was achieved at a distance of 2800 mm above the bubble generator. Small initial bubble size led to higher gas holdup and slump trend. By controlling the liquid mass flow in the nozzle, a reasonable gas holdup without slump could be achieved. A semi empirical correlation of gas holdup was established based on previous empirical correlations and experiment data, which provided accurate predictions.