The Interaction of Fuel-Bound Nitrogen and Fuel-Bound Chlorine During Air-Staged Incineration

Abstract

The simultaneous air-staged combustion of methyl amine (CH3NH2 and methyl chloride (CH3Cl) was studied in a two zone turbulent flow reactor at atmospheric pressure. The temperature in the first stage was held constant at 1750 K. The feed consisted of ethylene (C2H4), CH3NH2, CH3CI, air, and N2 (for first stage temperature control). Fuel-lean and fuel-rich mixtures were fed into the first stage. During the fuel-rich reed runs, secondary air was injected into the second stage to make the overall system fuel-lean. Measurements of species including NO, CO, CO2 and O2 were made in both stages. Three major observations were made: 1) The additon or CH3Cl during air staged combustion of CH3NH2 does not alter the attainment of an NO minimum emission from the second stage; 2) The optimal first stage equivalence ratio corresponding to the minimum NO in the second stage outlet is approximately 1.3 in both cases; and 3) The minimum NO emission level from air staged combustion significantly decreases when CH3Cl is added to the reed at constant equivalence ratio. A perfectly stirred – plug flow sequential reactor simulation is used with a detailed chemical reaction mechanism to model the observed species concentrations. The experimental data are well predicted, especially the staged combustion NO minimums. Model-based rate of production calculations suggests that the loss or OH radicals via OH + HCl = H2O + Cl and the consumption of N radicals via N + Cl + M = NCl + M slow the reaction N + OH = NO + H, leading to the reduced NO minimum emission during the simultaneous air-staged combustion or the fuel-bound chlorine and nitrogen species.