A numerical model for CO2 desorption including desorber packing, reboiler, and condenser was developed and validated against pilot plant data. Mass transfer data for both liquid and gas were obtained. Runs with pure water enabled check of the heat balance and estimation of the heat losses in the unit. The agreement between the experimental averaged and the simulated CO2 mass transfer rate was found to be good, with an average absolute deviation (AAD) and absolute deviation (AD) of 9.92% and 9.91%, respectively. The simulations slightly over-predict mass transfer in the low loading ranges and under-predict mass transfer in the high loading range. In addition, simulated and measured desorber temperature profiles agree very well for the low loading ranges where the desorber inlet liquid flow was well characterized. In cases where flashing of the desorber inlet flow occurs, it was found extremely important to know the enthalpy content. Desorber rich end pinches were found for most of the runs at low and medium loading. Using four different equilibrium models, it was shown that a simplified and a rigorous model would give very similar desorption performance predictions. The activity coefficient of water was found to have a strong influence on the agreement with experimental data. (C) 2008 Elsevier Ltd. All rights reserved.