Study of the Mercury Sorption Mechanism on Activated Carbon in Coal Combustion Flue Gas by the Temperature-Programmed Decomposition Desorption Technique
Murakami, A; Uddin, MdA; Ochiai, R; Sasaoka, E; Wu, S
| HERO ID | 1710224 |
|---|---|
| In Press | No |
| Year | 2010 |
| Title | Study of the Mercury Sorption Mechanism on Activated Carbon in Coal Combustion Flue Gas by the Temperature-Programmed Decomposition Desorption Technique |
| Authors | Murakami, A; Uddin, MdA; Ochiai, R; Sasaoka, E; Wu, S |
| Journal | Energy and Fuels |
| Volume | 24 |
| Issue | 8 |
| Page Numbers | 4241-4249 |
| Abstract | Effects of coexistent gases (HCl, SO(2), O(2), CO(2), and H(2)O) in simulated coal combustion flue gas on mercury removal by a commercial activated carbon (coconut shell AC) were investigated in a laboratory-scale fixed-bed reactor at 80 degrees C. To clarify the contribution of the Deacon reaction 2HCl + 1/2O(2) = Cl(2) + H(2)O (1) on the mercury sorption mechanisms, the experiments were also conducted in the presence of Cl(2) (in the absence of HCl). The characteristics (thermal stability) of the mercury species formed on the AC under the various sorption conditions were investigated by the temperature-programmed decomposition desorption (TPDD) technique. It was found that O(2) promoted mercury removal in the presence of SO(2); however, SO(2) suppressed mercury removal irrespective of the presence of O(2). The promotion of mercury removal by the presence of O(2) may result from the Deacon reaction. However, SO(2) seemed to inhibit the Deacon reaction. It is thought that mercury species formed on AC through the Deacon reaction was HgCl(x) (including HgCl(2)), which decomposed and desorbed at around 300 degrees C. This was supported by confirmation of the presence of HgCl(2) vapor in the reactor effluent gas in TPDD experiments. From the comparison of mercury removal in the gas containing 1 ppmv HCl and gas containing 0.5 ppmv Cl(2) system in the presence of SO(2), O(2), CO(2) and H(2)O, it was suggested that Cl(2) enhances mercury removal more efficiently than HCl. Therefore, efficient removal of mercury with AC is possible to achieve via promoting the Deacon reaction. The high-temperature TPDD peaks were observed at around 500 degrees C in TPDD spectra of the spent sorbents used in mercury removal in the presence of Cl(2) (or high concentrations of HCl), SO(2), O(2), CO(2), and H(2)O. This TPDD peak temperature range is very close to the decomposition temperature of HgSO(4). We suggest that the high-temperature mercury desorption peaks are related to the decomposition of mercury species similar to mercury sulfate containing chlorine (HgS(x)O(y)Cl(z)) on AC. |
| Doi | 10.1021/ef100288f |
| Wosid | WOS:000281029700018 |
| Is Certified Translation | No |
| Dupe Override | No |
| Comments | Source: Web of Science WOS:000281029700018 |
| Is Public | Yes |