Kinetics of the Removal of Hydrogen Chloride Gas Using Hydroxysodalite at High Temperatures

Abstract

Abstract-Hydrogen chloride (HCl) is an acidic pollutant that is present in the flue gases of most municipal and hazardous waste incinerators. It is important to treat gaseous HCl in incineration streams efficiently to avoid adverse environmental consequences. The removal of hydrogen chloride gas using hydroxysodalite (Na 8 Al 6 Si 6 O 24 (OH) 2 ) at high temperatures (600-900 °C) using a fixed-bed flow-type reactor was investigated in this study. HCl was efficiently removed from N 2 containing 1000-ppmv HCl with a reaction time of 2 h at high temperatures. The hydroxysodalite reacted efficiently with the HCl gas at temperatures between 600 and 800 °C, and was transformed into sodalite (Na 8 Al 6 Si 6 O 24 Cl 2 ). The amount of HCl fixed increased as the temperature increased to 800 °C but decreased when the temperature was increased to 900 °C because some of the hydroxysodalite and sodalite was transformed into nepheline (NaAlSiO 4 ). The most chlorine was fixed at 800 °C (the amount fixed was 56 mg/g). The reaction kinetics were assessed, and the pseudo-first-order and pseudo-second-order rate constants were calculated. Removal experiments showed that the removal process followed pseudo-second-order kinetics rather than pseudo-first-order kinetics. Increasing the temperature of the fixed-bed reactor to 800 °C increased the amount of HCl that was removed while keeping the removal kinetics almost the same.

Chemical Conversion of Paper Sludge Ash into Cation Exchanger Via Acid Leaching

“…Hydroxysodalite has low cation exchange capacity, but can be applied to remove hydrogen chloride gas at high temperature 31) . Zeolite-P can be applied to water purification, soil remediation, hydrogen adsorbent and so on [32][33][34][35][36] .…”