Thermodynamic Evaluation of Portuguese municipal solid waste gasification

Through a massive population growth, waste management has become one of the main concerns of our time. In Portugal the growing volume of municipal solid waste has become a central problem for municipalities, due to lack of space and the high costs to solve it. Gasification has received a renewed interest in the municipal solid waste treatment since it limits dioxins formation, presents higher efficiency and requires less expensive gas cleaning equipment when compared to available methods gas. However, to make to process more appealing to both private sector and government institutions is necessary to overcome some concerns related to the process. To expedite the mainstream of this technology a first and second law analysis conducted on Portuguese municipal solid waste was carried out. The thermodynamic method was coupled with a previously developed numerical model. Said model was validated using data from a pilot scale plant. Both energy and exergy values were investigated in order to evaluate Portuguese municipal solid waste as an energy source. Optimal operating point was found at 900 °C for an equivalent ratio of 0.25. Tar content energy values decreased as high as 80% when temperature was increased to 900 °C. A comparison between several gasification efficiencies was investigated.