NO/sub x/ emission control by particle quenching in an advanced glass making process

The formation of NO/sub x/ in an advanced glass melting (AGM) process has been studied. In this system, methane is combusted with preheated air at near stoichiometric conditions resulting in a potential for production of a high NO/sub x/ concentration in the exhaust. The minerals required for glass synthesis are entrained as a high loading concentration of fine particles in the preheated air supply. The particles are heated up in suspension by the combustion products. The thermal time scale for gas-particle heat transfer is chosen to be comparable to or less than NO/sub x/ formation kinetic time. This was projected to prevent formation of NO/sub x/ at a concentration corresponding to the adiabatic gas phase combustion temperature. The measured NO/sub x/ concentration in the glass melter exhaust is found to be significantly below anticipated NSPS requirements. A model is proposed for the processes in the AGM based on a kinetics/transport code. The decreased amount of NO/sub x/ formation is attributed to gas/particle thermal quenching effects and, possibly heterogenoeous catalytic reduction.