A model that takes into account the gas‐phase and liquid‐phase resistance to mass transfer has been developed, where the overall mass transfer coefficient (KOGa) is expressed as a function of the equivalent Sauter‐mean bubble diameter. This parameter was back calculated from mass transfer measurements made at a pilot plant on single pass sieve trays of 0.311 m diameter. Hydraulic parameters were measured for these trays as well. Mean bubble diameters were then correlated as a function of active area F‐factor and dispersion height for various tray geometries, and these correlations are used to predict point efficiencies on production plant trays up to 8.5 m in diameter.

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Direct wood liquefaction of pine sawdust (Pinus radiata) in a hydrogen donor solvent (tetralin), was studied in a 0.5 L autoclave using Co‐Mo/γ‐Al2O3 and Pt/γ‐Al2O3 supported catalysts. Uncatalyzed as well as Raney Nickel catalyzed runs were also performed for comparison purposes. Reaction temperature was kept at 673 K and total system pressure at 10 MPa in all cases. Weight ratio of solvent to solid loaded was 2:1, the gas phase being either H2 or N2. Independent runs were also performed with cellulose and lignin which are the main wood constituents. Reaction products were characterized by means of gas chromatography and solvent fractionation using specific solvents.

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A model is presented for the steady‐state simulation of a CO2 recovery pilot plant with aqueous monoethanolamine (MEA) solutions. CO2 absorption is performed in a column packed with 2.54 cm ceramic Pall rings. CO2 recovery is achieved in a 20 sieve tray steam stripping column. The packed column absorption model was fitted to the experimental data using the specific interfacial area of the irrigated packing as an adjustable parameter. The equivalent average bubble diameter was used as the adjusting parameter in the sieve tray stripping column. Modelling of both towers reproduces within 3% average error concentrations measured in a pilot plant. Measured temperatures were also well correlated.

A mass transfer model to predict tray efficiency on industrial GS process sieve trays is presented. Tray efficiencies are predicted from point efficiencies on large trays up to 8.5 m in diameter, by taking into account effects of liquid flow distribution, weeping, entrainment, gas mixing and liquid mixing in the downcomers. Predictions by the model agree with tray efficiencies measured at the heavy water plants.

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