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Reaction mechanisms of dry Ca-based sorbents with gaseous HCl

Journal Article · · Industrial and Engineering Chemistry Research; (United States)
DOI:https://doi.org/10.1021/ie00041a022· OSTI ID:6468808
 [1];  [2]
  1. Acurex Environmental Corp., Research Triangle Park, NC (United States)
  2. Environmental Protection Agency, Research Triangle Park, NC (United States). Air and Energy Engineering Research Lab.

Hydrogen chloride is one of the acid gas emissions resulting from municipal and hazardous waste combustion and can be neutralized by reaction with calcium-based sorbents downstream of the furnace. The mechanisms of HCl reaction with dry Ca(OH)[sub 2] or CaO sorbents in flue gas cleaning applications were investigated by differential scanning calorimetry (DSC), thermogravimetry, and X-ray diffraction. A short-time differential reactor (STDR) was used to contact 1,000 ppm HCl with dry sorbents at temperatures ranging from 100 to 600 C. The product of HCl reaction with Ca(OH)[sub 2] over the 100--600 C range in the STDR was identified as a solid solution of CaCl[sub 2] [center dot] 2H[sub 2]O and CaClOH. Subsequently, the Cl/Ca molar ratio in the product was determined to be less than 2. The product of the HCl reaction with CaO in the STDR over the 100--600 C range was identified as CaClOH. When scanned by DSC, samples of both CaO and Ca(OH)[sub 2] that were previously exposed to HCl in the STDR revealed an endotherm between 530 and 590 C. The amount of enthalpy correlated well with the chemically determined sample conversion.

OSTI ID:
6468808
Journal Information:
Industrial and Engineering Chemistry Research; (United States), Journal Name: Industrial and Engineering Chemistry Research; (United States) Vol. 34:2; ISSN IECRED; ISSN 0888-5885
Country of Publication:
United States
Language:
English