Clean Technology (청정기술)

The Korean Society of Clean Technology (한국청정기술학회)
권호 표지
DOI QR코드

DOI QR Code

A Reaction Kinetic for Selective Catalytic Reduction of NOx with NH3 over Manganese Oxide (NMO, MnO2, Mn2O3) at Low Temperature

망간산화물(NMO, MnO2, Mn2O3)을 이용한 저온에서의 NH3-SCR의 반응속도 연구

  • Kim, Min Su (Department of Environmental Energy Engineering, Graduate school of Kyonggi University) ;
  • Hong, Sung Chang (Department of Environmental Energy Engineering, Kyonggi University)
  • 김민수 (경기대학교 일반대학원 환경에너지공학과) ;
  • 홍성창 (경기대학교 환경에너지공학과)
  • Received : 2018.09.27
  • Accepted : 2018.10.25
  • Published : 2018.12.31
Download PDF
⟨ Previous Next ⟩

Abstract

In this study, NMO (Natural Manganese Ore), $MnO_2$, and $Mn_2O_3$ catalysts were used in the selective catalytic reduction process to remove nitrogen oxides (NOx) using $NH_3$ as a reducing agent at low temperatures in the presence of oxygen. In the case of the NMO (Natural Manganese Ore), it was confirmed that the conversion of nitrogen oxides in the stability test did not change even after 100 hours at 423 K. The Kinetics experiments were carried out within the range where heat and mass transfer were not factors. From a steady-state Kinetics study, it was found that the low-temperature SCR reaction was zero order with the respect to $NH_3$ and 0.41 ~ 0.57 order with the respect to NO and 0.13 ~ 0.26 order with the respect to $O_2$. As temperature increases, the reaction order decreases as a result of $NH_3$ and oxygen concentration. It was confirmed that the reaction between the $NH_3$ dissociated and adsorbedon the catalyst surface and the gaseous nitrogen monoxide (E-R model) and the reaction with the adsorbed nitrogen monoxide (L-H model) occur.

본 연구에서는 NMO (Natural Manganese Ore), $MnO_2$, $Mn_2O_3$ 촉매를 산소 존재 하에 저온에서 $NH_3$를 환원제로 이용하여 질소산화물(NOx)을 제거하는 선택적 촉매 환원법에 사용되었다. NMO의 경우, 안정성 실험에서 질소산화물 전환율이 423 K에서 100시간 후에도 변하지 않는 것을 확인하였다. 동력학 실험의 경우, 열 및 물질전달이 영향을 주지 않는 영역에서 수행하였다. 정상상태에서의 반응속도 연구는 저온 SCR반응에서 암모니아에 대하여 0차이고 일산화질소에 대해서는 0.41 ~ 0.57차였으며 산소에 대해서는 0.13 ~ 0.26차인 것을 확인하였다. 온도가 증가할 때, 암모니아와 산소 농도의 결과에 따라 반응차수가 감소함을 확인하였다. 촉매 표면에 해리흡착 된 암모니아와 가스상 일산화질소(E-R 모델)와의 반응 및 흡착 된 일산화질소(L-H 모델)와의 반응을 확인하였다.

Keywords

CJGSB2_2018_v24n4_307_f0001.png 이미지

Figure 1. NOx conversion of NMO as function of time at 423 K : (a) NO conversion, (b) NO2 concentration, (c) NH3 concentration (S.V. : 30,000 h-1, NO : 424 ppm, NO2 : 7 ppm, NH3 : 480 ppm).

CJGSB2_2018_v24n4_307_f0002.png 이미지

Figure 2. Grid of experimental conditions for NO and NH3 at 3 kPa of O2 carried out at 393, 423, and 455 K : NMO, MnO2, Mn2O3. (Exp. Condition: Loaded Cat.: 25 , 50, 100 mg Temp : 393, 423, 455 K, Variable : PNO, PNH3, PO2)

CJGSB2_2018_v24n4_307_f0003.png 이미지

Figure 3. Observed NO conversion as a function of the space time for various partial pressures at 423 K : (a) NMO, (b) MnO3, (c) Mn2O3. (PNH3: 40.5 Pa, PO2: 3 kPa).

CJGSB2_2018_v24n4_307_f0004.png 이미지

Figure 4. Observed NO conversion as a function of a partial NH3 pressure for various space times at 423 K : (a) NMO, (b) MnO3, (c) Mn2O3. (PO2 : 3 kPa, PNO : 40.5 Pa).

CJGSB2_2018_v24n4_307_f0005.png 이미지

Figure 5. Observed NO conversion as a function of a partial O2 pressure for various space times at 423 K : (a) NMO, (b) MnO3, (c) Mn2O3. (PNH3: 40.5 Pa, PNO: 40.5 Pa).

CJGSB2_2018_v24n4_307_f0006.png 이미지

Figure 6. The dependence of the NO conversion on the temperature over (a) NMO, (b) MnO3, (c) Mn2O3 (loaded cat: 50 mg, PNH3 : 40.5 Pa, PNH3 : 40.5 pa, PO2 : 3 kPa).

CJGSB2_2018_v24n4_307_f0007.png 이미지

Figure 7. Error as a function of calculated rate at 393 K : (a) NMO, (b) MnO3, (c) Mn2O3.

Table 1. The experimental conditions

CJGSB2_2018_v24n4_307_t0001.png 이미지

Table 2. Thermal stabilities absorbed NO complexes

CJGSB2_2018_v24n4_307_t0002.png 이미지

Table 3. Reaction orders of Mn oxides

CJGSB2_2018_v24n4_307_t0003.png 이미지

References

  1. Bosch, H., and Janssen, F., "Formation and Control of Nitrogen Oxides," Catal. Today, 2, 369 (1988). https://doi.org/10.1016/0920-5861(88)80002-6
  2. Wood, S. C., "Select the Right $IMO_x$ Control Technology," Chem. Eng. Prog., 90, 32 (1994).
  3. Cho, S. M., "Properly Apply Selective Catalytic Reduction for NO Sub (x) Removal," Eng. Prog., 90, 39 (1994).
  4. Forzatti, P., and Heterogen., L. L., "Recent Advances in De$NO_x$ing Catalysis," Chem. Rev., 3, 33 (1996).
  5. Alemany, L. J., and Berti, F., "Characterization and Composition of Commercial $V_2O_5&z$. sbnd; $WO_3&z$. sbnd; $TiO_2$ SCR catalysts," Appl. Catal. B: Environ., 10, 299 (1996). https://doi.org/10.1016/S0926-3373(96)00032-X
  6. Rahkamaa-Tolonen, K., Maunula, T., Lomma, M., Huuhtanen, M., and Keiski, R. L., "The Effect of $NO_2$ on the Activity of Fresh and Aged Zeolite Catalysts in the $NH_3$-SCR Reaction," Catal. Today, 100, 217 (2005). https://doi.org/10.1016/j.cattod.2004.09.056
  7. Qi, G., and Yang, R. T., "Ultra-active Fe/ZSM-5 Catalyst for Selective Catalytic Reduction of Nitric Oxide with Ammonia," Appl. Catal. B: Environ., 60, 13 (2005).
  8. Sjo vall, H., Blint, R. J., Gopinath, A., and Olsson, L., "A Kinetic Model for the Selective Catalytic Reduction of $NO_x$ with $NH_3$ over an Fe−zeolite Catalyst," Ind. Eng. Chem. Res., 49, 39 (2009).
  9. Ma, A. Z., and Grunert, W., "Selective Catalytic Reduction of NO by Ammonia over Fe-ZSM-5 Catalysts," Chem. Commun., 71 (1999).
  10. Long, R., and Yang, R. T., "Fe-ZSM-5 for Selective Catalytic Reduction of NO with $NH_3$: A Comparative Study of Different Preparation Techniques," Catal. Lett., 74, 201 (2001).
  11. Park, T. S., Jeong, S. K., Hong, S. H., and Hong, S. C., "Selective Catalytic Reduction of Nitrogen Oxides with $NH_3$ over Natural Manganese Ore at Low Temperature," Ind. Eng. Chem. Res., 40, 4491 (2001). https://doi.org/10.1021/ie010218+
  12. Tang, X., Hao, J., Xu, W., and Li, J., "Low Temperature Selective Catalytic Reduction of $NO_x$ with $NH_3$ over Amorphous M$NO_x$ Catalysts Prepared by Three Methods," Catal. Commun., 8, 329 (2007). https://doi.org/10.1016/j.catcom.2006.06.025
  13. Kang, M., Park, E. D., Kim, J. M., and Yie, J. E., "Manganese Oxide Catalysts for NOx Reduction with $NH_3$ at Low Temperatures," Appl. Catal. A: Gen., 327, 261 (2007). https://doi.org/10.1016/j.apcata.2007.05.024
  14. Kang, M., Park, J. H., Choi, J. S., Park, E. D., and Yie, J. E., "Low-temperature Catalytic Reduction of Nitrogen Oxides with Ammonia over Supported Manganese Oxide Catalysts," J. Chem. Eng., 24, 191 (2007).
  15. Kang, M., Yeon, T. H., Park, E. D., Yie, J. E., and Kim, J. M., "Novel $MNO_x$ Catalysts for NO Reduction at Low Temperature with Ammonia," Catal. Lett., 106, 77 (2006). https://doi.org/10.1007/s10562-005-9194-3
  16. Kapteijn, F., Singoredjo, L., Andreini, A., and Moulijn, J., "Activity and Selectivity of Pure Manganese Oxides in the Selective Catalytic Reduction of Nitric Oxide with Ammonia," Appl. Catal. B: Environ., 3, 173 (1994).
  17. Dekker, F., Bliek, A., Kapteijn, F., and Moulijn, J., "Analysis of Heat and Mass Transfer in Transient Experiments over Heterogeneous Catalysts," Chem. Eng. Sci., 50, 3573 (1995). https://doi.org/10.1016/0009-2509(95)00210-V
  18. Bosch, H., and Janssen, F., "Catalytic Reduction of Nitrogen Oxides: A Review on the Fundamentals and Technology," Catal. Today, 2, 433 (1988). https://doi.org/10.1016/0920-5861(88)80005-1
  19. Qi, G., and Yang, R. T., "Low-temperature Selective Catalytic Reduction of NO with $NH_3$ over Iron and Manganese Oxides Supported on Titania," Appl. Catal. B: Environ., 44, 217 (2003). https://doi.org/10.1016/S0926-3373(03)00100-0
  20. Turco, M., Lisi, L., Pirone, R., and Ciambelli, P., "Effect of Water on the Kinetics of Nitric Oxide Reduction over a High-Surface-Area $V_2O_5$/$TiO_2$ Catalyst," Appl. Catal. B: Environ., 3, 133 (1994). https://doi.org/10.1016/0926-3373(94)80001-4
  21. Huang, H., Long, R., and Yang, R., "Kinetics of Selective Catalytic Reduction of NO with $NH_3$ on Fe-ZSM-5 Catalyst," Appl. Catal. A: Gen., 235, 241 (2002). https://doi.org/10.1016/S0926-860X(02)00268-5
  22. Iwasaki, M., Yamazaki, K., and Shinjoh, H., "Transient Reaction Analysis and Steady-State Kinetic Study of Selective Catalytic Reduction of NO and $NO^+$ $NO_2$ by $NH_3$ over Fe/ZSM-5," Appl. Catal. A: Gen., 366, 84 (2009).