Simulação do processo Phosam para recuperação de amônia: avaliação energética e econômica.

Abstract

Ammonia is a by-product produced in the steel industry, which has high value added and is potentially polluting, that is, its recovery is as economically attractive as it is necessary, considering environmental regulations. The Phosam process then emerges as an efficient way to produce anhydrous ammonia using coke oven gases, which makes it possible to obtain it with 99.99% of purity. However, this method is little explored in the literature, especially in terms of energy use. Considering the above, this research aimed to evaluate the Phosam process in terms of energy consumption through the use of a process simulator, considering the following two situations: the use of direct steam injection in the stripper and fractionator columns, and the indirect steaming via reboilers. In order to do that, the process was implemented on the Aspen Plus™ software, and the quality of the anhydrous ammonia obtained, as well as its flow, were investigated in the face of changes in the amount of heat supplied to the columns, in the reflux ratio (RR), in the boiling point ratio (BR), and in the feed tray through sensitivity analyses. With such results, it was possible to define the best operational conditions and quantify the demand for steam and its cost considering both cases. Finally, it was concluded that the use of direct steam injection in the stripper and fractionator columns has the lowest energy consumption, or savings of around 66% when translated into utility costs.