The HCl evolution behavior in the process of sulfation of KCl, CaCl
2 and NaCl was studied by using a lab-scale gas flow-type tubular reactor, in simulated conditions of municipal waste incinerations, under mixed gas of SO
2: 0.3–1.3 vol%, O
2: 2.5–15 vol%, H
2O: 5–20 vol%, in the temperature range of 623–1123 K. The sulfation rates of KCl, CaCl
2 and NaCl changed distinguishably with the temperature above 923 K, for each inorganic chloride of KCl, CaCl
2 and NaCl. Comparing the time-changes of the concentration of HCl released from KCl, CaCl
2 and NaCl, the rate of HCl evolution from CaCl
2 was the highest; the maximum concentration of HCl discharged from CaCl
2 was more than 5 times higher than those from NaCl and KCl at 923 K. The reaction kinetic parameters like the rate constant and the reaction orders with respect to SO
2, O
2 and H
2O partial pressure for the sulfation of NaCl, KCl and CaCl
2 were determined. It was suggested that the mechanism of formation of HCl by sulfation of KCl, CaCl
2 and NaCl was different above and below the temperature range of 850–900 K. A higher sulfation rate of KCl, CaCl
2 and NaCl might be attributable to a partial melting and/or volatilization of these inorganic chlorides at the temperatures higher than the temperature range of 850–900 K. The effect of SO
2 partial pressure on the sulfation rate was 2–4 times larger for NaCl than for KCl and CaCl
2. For the sulfation of KCl, the reaction order with respect to the O
2 partial pressure was almost a half of that of NaCl. On the other hand, the rate of sulfation of CaCl
2 was almost independent on the O
2 partial pressure. The dependence of H
2O partial pressure on the sulfation rates of KCl, CaCl
2 and NaCl was almost the same in lower temperatures of 623–923 K. However, the reaction order with respect to H
2O at 923–1123 K became 2–4 times larger than that in the lower temperature regions.
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