Analysis of syngas reburn technology for industrial boilers with advanced chemical engineering models

The outcome of an integrated methodology for analysis of combustion processes applied to technical feasibility of controlling NOx emissions and unburned carbon in ash from industrial scale plants was presented. The modeling methodology was based on an integrated use of furnace probing measurements coupled with different simulation tools: CFD code (IPSE) for 3D simulation of combustion chambers, PROATES for the convection pass, and Chemical Engineering Models (RNA) for pollutant emissions and burnout predictions. The solid phase included heterogeneous NO reduction by char and heterogeneous char oxidation with a detailed population balance (800 size burnout classes) keeping track of size, density change and burnout. As working case, to better explain the potentiality offered by this analytical approach, a study addressed to evaluate the best firing configuration for a tangentially-fired utility boiler supplied with pulverized coal by employing synthesis gas (syngas) as secondary fuel is presented. The case studied was chosen as increasing attention to the use of renewable and sustainable energy resources has led to consider, as near term option, the possibility of co-firing syngas (i.e. synthetic gas produced by gasification of biomass or waste) with coal in the existing large-scale pulverized coal power plants. This is an abstract of a paper presented at the 30th International Symposium on Combustion (Chicago, IL 7/25-30/2004).