• Applied Chemistry for Engineering
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• v.10 no.2
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• pp.263-267
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• 1999

NO removal activity (per unit of mass) of the used catalyst was seriously decreased as low as 27% of the new catalyst. Since the surface area of the used catalyst was 63% of that of the new one, the mojor reason for the lessened activity of the used catalyst compared to the new one may be due to the decreased surface area by sintering and surface concentration of active materials. Poison may be regarded as another important factor, since it affect the active site of catalyst by heavy metals. To recycle the used catalyst, we focused on the removal of poisoning agents from the catalyst. By using $80^{\circ}C$ water for 30 min upto 2 h, the recycled catalyst demonstrated the best activity and efficiency, which may be due to the removal of both K and Na. Although the recovered activity (per unit of surface area) of the catalyst was 79% compared to the new one, the activity (per unit of mass) of the recovered catalyst was only 49% compared of the activity of fresh catalyst.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.1
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• pp.54-60
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• 2008

Deactivation of SCR catalyst applied in Orimusion fuel power plant was investigated to develope the technique for the regeneration of deactivated SCR catalyst and optimize the operation of SCR facility. The characterization study of the catalysts was carried out using XRD, ICP-AES, SEM and EDS. The NO$_X$ removal activity and SO$_2$ oxidation activity of the catalysts were measured. The NO$_X$ conversion of the deactivated catalyst was 5$\sim$10% lower than that of the fresh catalyst and the value of SO$_2$conversion to SO$_3$ over the deactivated catalyst was about 0.59% higher than that of the fresh catalyst. Vanadium(V), Magnesium(Mg) and Sulfur(S) were largely accumulated in the deactivated catalyst. The accumulation of Vanadium(V) and Sulfur(S) is due to the components of the Orimulsion fuel and the accumulation of Magnesium(Mg) is due to MgO that is injected in the boiler to prevent the oxidation of SO$_2$ to SO$_3$. The diffraction line of the TiO$_2$ of the deactivated catalyst was identified as the crystalline peaks of anatase as the fresh catalyst.

• Journal of Korean Society for Atmospheric Environment
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• v.12 no.4
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• pp.421-428
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• 1996

In this study, in order to make up its draw-back in Cu-ZSM-5 catalytic system, some of transition metals or alkaline earth metals were cocation-exchanged in Cu-ZSM-5. Among various cocation-ion-exchanged ZSM-5 catalysts, Mg/Cu-ZSM-5 has been found the most active and durable in NOx reduction even at high oxygen content as well as at the presence of water vapor. The role of Mg in ZSM-5 is supposed to prevent the dealumination of aluminum ions in super-cage even at harsh hydro-thermal conditions, and also it seems to stabilize the Cu ions in the structure. In order to prepare commercially available catalysts, Mg/Cu-ZSM-5 catalysts were wash-coated on the surface of honeycomb type monolith, and tested in terms of catalytic activities. As a result, it was found that the catalyst prepared bt the wash-coating showed satisfactorily high NOx conversion for the practical use in SCR process.