Limestone%26apos;s performance as a solid adsorbent for HF and HCl generated in refrigerant destruction applications

作者：Akuetteh Tekai; Donaldson Adam Andrew^*

来源：Korean Journal of Chemical Engineering, 2014, 31(10): 1885-1891.

DOI：10.1007/s11814-014-0150-z

• HF
• HCl
• Refrigerant Destruction
• Solid Adsorption Media
• Shrinking Core Model

The viability of two solid adsorbents, limestone and cement powder, for use in a flow-through packed-bed column for HCl and HF gas neutralization following refrigerant destruction was studied. Neutralization tests performed at 408 K using 5% HCl in N-2 and 5% HF in N-2, showed that limestone had a significantly higher adsorption capacity for both HF and HCl. similar to 49% of fed HCl, and between 7.8%-16.2% of fed HF gases were adsorbed by 7 g of limestone for a gas flow rate of 6.67x10(-6) m(3)/s (STP) over 30 to 180 minutes. Effective diffusivities (D (e) ) of HCl and HF into the limestone particles were 1.5x10(-9) and 2.2x10(-9) m(2)/s, respectively, indicating that a solid diffusion mechanism dominance would limit the suitability of this method as a solid adsorbent in the tested form. Under these conditions, complete particle conversion times were 227 hours for HCl-limestone and 154 hours for HF-limestone. Considering the long conversion times observed, shorter conversion times would require micron-scale particle sizes, suitable for entrained flow but not for a packed-bed arrangement. A Na2CO3/Limestone slurry used to neutralize the reactor effluent proved efficient within this system, and may be a more suitable alternative for acid neutralization involving HF.

• 出版日期2014-10