• Journal of Korean Society of Environmental Engineers
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• v.32 no.10
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• pp.928-935
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• 2010

A bag filter system was partially burnt down during a trial run of waste wood incineration boiler. This brought about unburned hydrocarbon which caused a rapid deactivation of low temperature SCR catalyst set up in two stage after the bag filter. The deactivated catalyst was investigated in order to trace the origin by several characterization methods such as XRD, EDX, BET, TGA, SEM. The deactivated catalyst was regenerated by different methods such as acid washing, water washing in ultrasonication, and calcination treatment under air condition. It is found the calcination treatment under air condition at $450^{\circ}C$ for 2 hours to be the best regeneration method. The catalytic activity was measured in the form of 2 cm ${\times}$ 2 cm ${\times}$ 10 cm (catalyst weight 10 g) honeycomb type. A deNOx efficiency of the regenerated catalyst showed 100% at $180^{\circ}C$ which is the same level of fresh one.

• Applied Chemistry for Engineering
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• v.30 no.6
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• pp.731-736
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• 2019

In this article, Pt/TiO₂ was manufactured in the form of powder and honeycomb, and the influence of SO₂, which is a poisonous substance to catalyst, and regeneration method were investigated. The catalytic activity of Pt/TiO₂ before and after the exposure to SO₂ was also compared. The initial activity of Pt/TiO₂ was proportional to the injected H₂ concentration (1~5%). And the optimum temperature of the catalyst and conversion rate of H₂ were 183 ℃ and 95%, respectively. It was confirmed that when exposing 2,800 ppm of SO₂ to the powder and honeycomb Pt/TiO₂, the performance of catalyst was not measurable and also 0.69% sulfur (S) remained on the catalyst surface. As a result of the cleaning and heat treatment for the poisoning catalyst, the activity of the powder catalyst exhibited a conversion rate of H₂ greater than 96%. Whereas, the honeycomb catalyst showed a conversion rate of H₂ greater than 95% when it was regenerated through the heat treatment of H₂ or air atmosphere.

• 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.

• Applied Chemistry for Engineering
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• v.19 no.3
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• pp.259-263
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• 2008

The catalytic activity of the used catalyst, $V_2O_5/TiO_2$, for MSW incinerators was investigated focusing on its regeneration. As the result of the experimental analysis, the NOx removal efficiency difference between the fresh catalyst and used catalyst is about 60% at $260^{\circ}C$ and 1, 2-dichlorobenzen (1, 2-DCB) removal efficiency difference is about 14% at $200^{\circ}C$, in honeycomb test. And the catalysts, both the fresh and used, were characterized by XRD, TGA, and ICP techniques in order to investigate the deactivation. On the basis of the results, it is found that the used catalyst is deactivated by ammonium-sulfates, heavy metals (Pb, As etc.), alkali metals (Ca), and phase transfer of $TiO_2$. Also calcination treatment under nitrogen and air condition was excellent than washing and calcination treatment.