Treatment of Hydrochloric Acid in Flue Gas from Municipal Solid Waste Incineration with Ca–Mg–Al Mixed Oxides at Medium–High Temperatures

Abstract

A calcium–magnesium–aluminum (Ca–Mg–Al) mixed oxide sorbent was synthesized for the removal of HCl at medium–high temperatures. The operating conditions were specified in terms of the temperature of the gas (300–700 °C), the initial HCl concentration (500–1000 ppm), and the mass flow rate (0.5–1.3 L/min). X-ray powder diffraction (XRD) was applied to investigate the characteristics of Ca–Mg–Al mixed oxides. The results show that, because of the better properties of Ca–Mg–Al mixed oxides than traditional sorbents, which is related to the special structure in as-prepared, the reaction between HCl and Ca–Mg–Al mixed oxides is accelerated. The adsorption capacity of Ca–Mg–Al mixed oxides is the highest when compared to MgO, NaHCO3, and CaO. The removal efficiency of Ca–Mg–Al mixed oxides is more than 95% and even up to 99% under all of the operating conditions.