This project successfully designed and carried out the optimum desulfurization method for the Shahid Rajaee power plant. Sulfur emissions are proved to be among the most hazardous emissions from the fossil fuel leading to various human diseases and respiratory illnesses and acid rains. Shahid Rajaee power plant ordered this project in order to reduce its sulfur emission using new engineering methods. Various desulfurization methods were designed for the client and finally, the economically optimum method is selected for the pilot unit capable of reducing the power plant sulfur emission to the new environmental protection agency standards.