Abstract: A process analysis has been made for soot recovery system of large scale ammonia plant. Mathematical models have been set up for calculating the material and heat balance of the system, and a model has been suggested for calculating the naphtha stripping tower plate by plate. On this basis, steady state simulation for the system has been made by sequential modular approach. The ash distribution in the system and the pH of the liquid phase have also been calculated. The results agree well with design values and values from plant.