Experimental and numerical analysis of a waste-to-energy plant operation

In this paper the authors present experimental and numerical investigations aimed at characterization of different operating conditions of an existing HERAmbiente S.p.A. waste-to-energy plant, located in Pozzilli, Italy. A 5-days experimental campaign has been conducted during which data from existing instrumentation installed on the combustion chamber of the plant has been collected and additional temperature measurements have been performed into the first channel of the combustion chamber by means of a carbide tungsten measuring bar equipped with four k-type thermocouples and kept in place during the whole experimental campaign. Besides, during the 5-days campaign the chemical characteristics of the RDF actually used to fed the plant have been analysed and proper uncertainty analysis has been conducted on the collected experimental data. Moreover in the present paper the authors propose a general simplified thermodynamic model able to predict the operating conditions of a wasteto- energy plant under consideration. The proposed model does not employ correlations based on empiric observations or on experimental data regressions and is generally applicable to any waste-to-energy plant. The developed numerical tool is here applied to the HERAmbiente S.p.A. plant in Pozzilli, Italy, also allowing the verification of the constraint imposed by the European legislation on the temperature of the combustion products. Input parameters are determined from measurements and the obtained results are validated against experiments, showing a good agreement. Even though the proposed numerical tool is based on the assumption that exhaust follow a one-dimensional path within the combustion chamber, it offers several advantages, such as the ability to: i) employ as input data actual reactants rates and chemical characteristics; iii) describe the RDF gasification process without the necessity of employing correlation; iv) associate the required uncertainty to the calculated data. Besides, results from the proposed model allow the definition of input data and boundary conditions for detailed 3D CFD simulation of the thermo-fluid-dynamic field within the plant combustion chamber.