HCl Removal Using Calcined Ca–Mg–Al Layered Double Hydroxide in the Presence of CO₂ at Medium–High Temperature

Abstract

This present work aimed to investigate the influence of CO2 on HCl removal using calcined Ca−Mg−Al layered double hydroxides (CaMgAl-LDHs) at medium−high temperature (400−800 °C) in a fixed-bed reactor. It was revealed that a moderate CO2 concentration (~6%) in the flue gas of the municipal solid-waste incinerators could reduce the HCl capacity of the CaMgAl-layered double oxides (CaMgAl-LDOs). The highest capacity for HCl removal was observed over the CaMgAl-LDOs at 600 °C. However, sintering was also detected when the reaction temperature was below the calcination temperature (600 °C). Moreover, the decreasing HCl adsorption capacity of CaMgAl-LDOs was attributed to the existence of CO2 in the flue gas, which could efficiently inhibit the decomposition of carbonates as well as the conversion into metal chloride during the HCl removal process.

Keywords

• hcl
• layered double hydroxide
• co₂
• medium-high temperature