Joint Meeting of The Scandinavian-Nordic and Italian Sections of The Combustion Institute An Integrated Kinetic Based Modelling Approach to Alkali-Salt Formation and Deposition in Pf Boilers 1 M. Corsi, 2 M. Falcitelli, 1 C. La Marca, 1 S. Malloggi, 1 N. Rossi, 3(*) L. Tognotti 1 ENEL S.p.A. Produzione Ricerca, Via A. Pisano, 120 - 56122 Pisa – ITALY 2 TEA Ambiente srl - Piazza Mazzini, 1 – 56127 Pisa – ITALY 3Università degli Studi di Pisa - Dipartimento di Ingegneria Chimica, Chimica Industriale e Scienza dei Materiali – Via Diotisalvi 2, 56100 Pisa – ITALY INTRODUCTION In the present study a numerical approach to the simulation of boiler conditions was extended to both explain and evaluate the vapour phase chemistry of alkali and chlorine and the alkali salt deposition mechanisms on heat transfer surfaces of the convection pass. The modelling methodology is based on an integrated use of different simulation tools: CFD (IPSE), PROATES TM and Chemical Engineering Models (RNA). A first study on the impact of different blending of coal and RDF on a real plant is presented, showing that the numerical approach can be used to predict the increase of alkali salt deposition on superheater tube banks. NUMERICAL MODELS At present ENEL numerical approach to the simulation of boiler conditions consists in a CFD code (IPSE) for the 3D simulation of the main chemical and physical conditions of the fluid flows inside industrial combustion chambers, in the PROATES TM code providing a mono- dimensional model of the convection pass which determines heat exchanges between gas and boiler steam, gas and metal temperature and in a subsequent schematisation of the modelled volume with a chemical engineering model called Reactor Network Analysis (RNA). The latter consists of an equivalent network of ideal, perfectly stirred, reactors extracted from the results of CFD simulation by an automatic zoning algorithm. Detailed reaction mechanisms are then applied over the reactor network and a more accurate calculation of the combustion yields is performed. The Reactor Network Analysis is based on a mechanistic approach to the combustion chemistry. Until now it was applied for the prediction of pollutant emission of gaseous species (NOx, SOx, CO, H 2 S) using detailed reaction schemes; recently it was extended to include the calculation of char oxidation. A scheme of the approach that was developed for predicting the formation and deposition of alkali-salt in pulverised coal fired boilers is the following: ¸ A three-dimensional model of the combustion chamber was performed to predict local temperatures, heat fluxes, flow rates, char burnout and concentrations of main species. This was achieved employing IPSE CFD code, which solves steady, three-dimensional, turbulent flow, heat transfer, and chemistry of pulverised coal combustion [1]. ¸ The convection pass was schematised with a mono-dimensional model which utilises PROATES TM code for calculating all the mass and heat exchanges between the gas and boiler fluids [2]. (*) Corresponding Author 1.12.1