EFFECT OF SO2 ON REMOVAL OF HCl FROM SURFACE OF Ca(OH)2 ABSORBER
The use of calcium hydroxide[Ca(OH)2]as a solid reactant for the removal of hydrogen chloride(HCl)from industrial flue gas streams is a simple and effective process solution.There are many scenarios in practical application where HCl needs to be pre-removed before subsequent pollutant treatment.Nevertheless,sulfur dioxide(SO2)in flue gas has instinctive and strong competition with HCl on the alkaline absorbent surface,resulting in detrimental effects and making the removal mechanisms confused,and previous studies have not yet achieved a convincing consensus.To solve this issue,this paper designed a series of experiments on a fixed-bed reactor to evaluate the effect of SO2 on the performance of the absorber in removing HCl.The competition mechanism of SO2 to HCl was further studied by combining the characterization results and thermodynamic characteristics.The results indicated that at the surface of the Ca(OH)2 absorber,HCl had a better preference on active sites than SO2,thus HCl was able to enter the interior of the absorber to continue the reaction.During the competition process,SO2 reduced the surface activity by depleting the active sites on surface of the Ca(OH)2 absorber,and forming a product layer,thus adversely affecting the removal of HCl.These findings contribute to the elucidation of SO2 competition to HCl on the calcium-based adsorbent in sintered flue gas.
HClalkaline absorbentSO2Ca(OH)2fixed bed experimentremoval performance