Simulation of a two-stage dry process for the removal of acid gases in a MSWI

Power generation from municipal solid wastes is an attractive technology in the area of renewable energy utilization. Because of the restrictive pollutant emission limits dictated by European Union Directives, it is very important to optimize the gas cleaning system to reduce the environmental impact caused by incineration, also taking into account economic aspect. In the present study a simplified conversion model for the assessment of removal efficiency of acid gases from flue gas was developed. The model is based on the ratio between the rate of solid reactants and the rate of incoming acid gases with respect to the stoichiometric ratio. The model was implemented with the Aspen Hysys code to simulate a two-stage flue gas cleaning system. Simulations were based on design data of an existing RDF incineration plant and can be easily adjusted to fit other design data. The optimal feed rate of reactants for a fixed removal efficiency was estimated through the proposed model.