Simulation strategies for regenerative chambers in glass production plants with strategic exhaust gas recirculation system

Abstract

Glass production is an energy-intensive and a high-polluting industry. This study has the aim to describe the computational approaches developed and set up for the analysis of the innovative Strategic Waste Gas Recirculation (WGR) System applied to the glass industry to new or existing furnaces. The final goal is to reduce the production of NOx during combustion making a primary combustion zone poor of oxygen. In order to have a controlled combustion in the primary zone it is of utmost importance to properly design the recirculation system to get the desired distribution of the recirculated gases in a specific zone over the methane injection. Moreover, the WGR system can have a second positive effect: it enhances the thermal performance of the regeneration system due to the radiating capacity of the exhaust flow recirculated that contains CO2 and H2O molecules. A CFD approach is presented and its applications to the design and optimization of WGR system are discussed. A numerical model for the evaluation of the emissive properties of radiant gases is developed and used for a parametric analysis on the thermal effects introduced by the WGR system.

Numerical Prediction of the Flow Structure Inside Components of Industrial Glass Furnace Systems

“…a) fluid domain -b) modified edges on the 3D geometry -c) reference brick Also in this case the commercial Ansys Fluent software has been used for the simulations, with the same finite volume approach. The so-called hot phase of the regenerative process is considered [6,8]: the exhaust gases from the combustion chamber enter the port neck and flow through the regenerative chamber to transfer their heat content to the refractory system (that will preheat the combustion air in the following "cold phase" of the regenerative process). A crucial design requirement for this system is the flow uniformity at the top surface of the checker domain in order to have a uniform distribution of gases through the regenerative part of the chamber.…”

“…In order to achieve a good effectiveness of the regenerative heat recovery system, it is necessary to provide a uniform flow distribution into the system starting from the chambers entrance [5][6][7][8].…”

“…The above situation will certainly affect the flow solution details from the CFD analysis with respect to the reference "ideal" case of a CAD design with sharp edges. The CFD approach has proven to be an effective tool for flow simulation inside components of industrial systems [5][6][7][8] and also enhanced CFD approaches with specific models for gas emissivity [6] and real gas effects [9] have been developed, especially for heat transfer or combustion applications. The paper is aimed at verifying the effects of the geometrical details of the edges on the flow structure to understand if the standard CFD approach with sharp edges is actually representative of the flow structure and if the above geometrical details need to be taken into account into the CFD based design strategy for glass production plant components.…”

Strategies for the Numerical Modelling of Regenerative Pre-heating Systems for Recycled Glass Raw Material

“…In the direct model the size of raw material (related to the porosity and consequently the porous resistance) has been varied following Eq. (8)(9). Figure 4 compares the volumetric temperature trends over time for different dimensions Lm of the raw material.…”

“…This system has been optimized to reach high efficiency values thanks to several numerical and experimental studies [2][3][4]. The research team from the University of Genoa has gained relevant experience in the simulation of regenerative glass production plants [5][6][7], but also in gas recirculation strategies for the reduction of NOx emissions [8,9].…”