New correlation for liquid hold-up of sodium citrate buffer solution in a Raschig ring packed column

Dynamic liquid hold-up was measured with an air/aqueous sodium citrate buffer solution at 20–40 °C, and an air/water system at 23 °C, in a 0.1 m diameter/1 m high glass column covered by a heat-isolating vacuum jacket and packed with 0.012 m nominal size ceramic Raschig rings. The superficial gas velocity range was extended to 1.2 m s⁻¹. Experimental results of this work were compared with literature data, with different correlations and with a general equation. All expressions were found to be unacceptable for the air/buffer system and useable for the air/water system. In the case of the air/buffer solution a new correlation is recommended on the basis of our measured data and literature values.