AbstractA six inch diameter sieve plate absorption column was used to assess the effect of perforation size on the performance of sieve trays under otherwise identical conditions. Four separate test trays with equal gas flow areas but perforations of 1/8‐inch, 1/4‐inch, 1/2‐inch and 1‐inch respectively, were used with the liquid phase absorption‐controlled system of carbon dioxide — water at 77°F and approximately 830 mm. mercury.Comparisons of overall efficiencies indicated that the trays with 1‐inch diameter perforations had efficiencies similar to, or slightly lower than those of 1/8‐inch diameter. Concentration profiles within the froth were measured, with distinct profiles being observable in both the horizontal and vertical directions.This indicated that neither the plug flow nor the completely mixed models accurately described the actual transfer process. Accordingly, comparisons of volumetric mass transfer coefficients computed from both models were made. Comparison of volumetric mass transfer coefficients showed that for most gas and liquid flowrates the plates with 1‐inch perforations performed as well as plates with smaller holes. For this system it was concluded that trays with large holes would be much better suited to fouling services and, indeed, they would be only marginally less attractive than trays with smaller hole