Numerical and Experimental Investigation of Oxy-Fuel Combustion for Application in Glass Melting Furnaces

摘要

In glass melting furnaces, high temperatures (>1600°C) are required in order to melt the raw materials in the furnace. These high process temperatures are usually achieved by means of air preheating and near stoichiometric conditions, leading to a significant production of undesired NO_X. Oxy-fuel combustion offers another way to achieve high temperature levels while drastically reducing NO_X emissions which is one reason why this technology is considered with great interest by glass manufacturers. Contrary to oxy-fuel applications in power plants, flue gas is not recirculated since elevated process temperatures are necessary for the production process. In the course of an ongoing German research project called “O2-Glaswanne”, the Gaswarme-Institut e. V. Essen (GWI) investigates how to best use this technology in glass melting furnaces, one aim being to increase the heat flux into the glass melt, thus increasing energy efficiency. Five oxy-fuel burners of different types were examined experimentally in GWI’s test rig. Temperatures and species concentrations were measured. This measurement campaign was accompanied by a series of CFD simulations. In a second step, operational furnaces are investigated by both experimental and numerical means. This paper discusses the results of the experimental and numerical investigations on a semi-industrial test rig in order to draw conclusions on how to improve the application of oxy-fuel technology in glass furnaces. The comparison of numerical and experimental data also allows for an evaluation of the performance of the CFD models as a tool to optimize furnace design.