Clean Technology (청정기술)

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

DOI QR Code

Effect of Reaction Gases on PFCs Treatment Using Arc Plasma Process

아크 플라즈마를 이용한 과불화합물 처리공정에서 반응가스에 의한 효과

  • Park, Hyun-Woo (Department of Chemical Engineering, Inha University) ;
  • Choi, Sooseok (Regional Innovation Center for Environmental Technology of Thermal Plasma, Inha University) ;
  • Park, Dong-Wha (Department of Chemical Engineering, Inha University)
  • 박현우 (인하대학교 화학공학과) ;
  • 최수석 (인하대학교 열플라즈마환경기술연구센터) ;
  • 박동화 (인하대학교 화학공학과)
  • Received : 2013.03.06
  • Accepted : 2013.03.27
  • Published : 2013.06.28
Download PDF
⟨ Previous Next ⟩

Abstract

The treatment of chemically stable perflourocompounds (PFCs) requires a large amount of energy. An energy efficient arc plasma system has been developed to overcome such disadvantage. $CF_4$, $SF_6$ and $NF_3$ were injected into the plasma torch directly, and net plasma power was estimated from the measurement of thermal efficiency of the system. Effects of net plasma power, waste gas flow rate and additive gases on the destruction and removal efficiency (DRE) of PFCs were examined. The calculation of thermodynamic equilibrium composition was also conducted to compare with experimental results. The average thermal efficiency was ranged from 60 to 66% with increasing waste gas flow rate, while DRE of PFCs was decreased with increasing gas flow rate. On the other hand, DRE of each PFCs was increased with the increasing input power. Maximum DREs of $CF_4$, $SF_6$ and $NF_3$ were 4%, 15% and 90%, respectively, without reaction gas at the fixed input power and waste gas flow rate of 3 kW and 70 L/min. A rapid increase of DRE was found using hydrogen or oxygen additional gases. Hydrogen was more effective than oxygen to decompose PFCs and to control by-products. The major by-product in the arc plasma process with hydrogen was hydrofluoric acid that is easy to be removed by a wet scrubber. DREs of $CF_4$, $SF_6$ and $NF_3$ were 25%, 39% and 99%, respectively, using hydrogen additional gas at the waste gas flow rate of 100 L/min and the input power of 3 kW.

화학적으로 안정한 과불화합물을 처리하기 위해서는 많은 양의 에너지를 필요로 한다. 이러한 단점을 극복하기 위해서 저전력 아크 플라즈마 시스템을 개발하였다. 분해대상은 $CF_4$, $SF_6$, $NF_3$가 플라즈마 토치로 직접 주입되었으며, 아크 플라즈마 토치의 열효율을 측정하여 실출력을 계산하였다. 실출력과 폐기체 유량 변화 그리고 추가적인 반응가스에 의한 분해효율을 확인하였다. 또한 열역학적 평형조성 분석을 수행하여 실험 결과와 비교하였다. 토치의 열효율은 60~66%의 결과를 보였으며 폐가스 유량이 증가함에 따라 분해효율이 감소하였고 입력전력이 늘어남에 따라 분해효율이 상승되었다. 추가적인 반응 가스가 없이 $CF_4$, $SF_6$, $NF_3$의 분해효율은 입력전력이 3 kW, 폐가스 유량이 70 L/min인 조건에서 각각 4, 15, 90%를 보였다. 반응가스로 산소와 수소를 이용하여 분해효율을 급격하게 증가시킬 수 있었으며, 실험 결과 산소보다 수소를 사용하였을 경우가 분해효율 상승효과와 부산물 제어에 효과적인 것을 알 수 있었다. 수소의 경우, 발생되는 부산물은 불화수소산이었으며 이는 일반적인 습식 스크러버를 이용하여 처리가 용이한 물질이다. 수소를 이용한 화학반응에서 입력전력이 3 kW, 폐가스유량이 100 L/min인 조건에서 $CF_4$가 25%, $SF_6$가 39%, $NF_3$가 99%의 분해효율을 각각 나타냈다.

Keywords

References

  1. http://unfccc.int/key_steps/bali_road_map/items/6072.php
  2. Gupta, J., Olsthoorn, X., and Rotender, E., "The Role of Scientific Uncertainly in Compliance with Kyoto Protocol to the Climate Change Convention," Environ. Sci. Policy, 6, 475-486 (2003). https://doi.org/10.1016/j.envsci.2003.09.001
  3. Chang, M.. B., and Chang, J. S., "Abatement of PFCs from Semiconductor Manufacturing Processes by Nonthermal Plasma Technologies: A Critical Review," Ind. Eng. Chem. Res., 45, 4101-4109 (2006). https://doi.org/10.1021/ie051227b
  4. Mohindra, V., Chae, H., Sawin, H. H., and Mocella, M. T., "Abatement of Perflourocompounds (PFCs) in a Microwave Tubular Reactor Using $O_2$ as an Additive Gas," IEEE Trans. Semicond. Manuf., 10, 399-411 (1997). https://doi.org/10.1109/66.618213
  5. Radoiu, M. T., "Studies on Atmospheric Plasma Abatement of PFCs," Radiat. Phys. Chem., 69, 113-120 (2004). https://doi.org/10.1016/S0969-806X(03)00455-9
  6. Wang, Y. F., Wang, L. C., Shih, M. L., and Tsai, C. H., "Effects of Experimental Parameters on $NF_3$ Decomposition Fraction in an Oxygen-based RF Plasma Environment," Chemosphere, 57, 1157-1163 (2004). https://doi.org/10.1016/j.chemosphere.2004.08.026
  7. Tsai, W. T., "Environmental and Health Risk Analysis of Nitrogen Triflouride ($NF_3$), a Toxic and Potent Greenhouse Gas," J. Hazard. Mater., 159, 257-263 (2008). https://doi.org/10.1016/j.jhazmat.2008.02.023
  8. Reichardt, H., Frenzel, A., and Schober, K., "Environmentally Friendly Wafer Production: $NF_3$ Remote Microwave Plasma for Chember Cleaning," Microelectron. Eng., 56, 73-76 (2001). https://doi.org/10.1016/S0167-9317(00)00505-0
  9. Takubo, T., Hirose, Y., Kashiwagi, D., Inoue, T., Yamada, H. Nagoka, K., and Takita, Y., "Metal Phosphate and Fluoride Catalysts Active for Hydrolysis of $NF_3$," Catal. Commun., 11, 147-150 (2009). https://doi.org/10.1016/j.catcom.2009.09.005
  10. Houghton, J. T., Meira, L. G., Callander, B. A., Harris, N., Kattenberg, A., and Maskell, K., Climate Change 1995-The Science of Climate Change, Cambridge University Press, New York, 1996, pp. 121.
  11. Dillon, T. J., Horowitz, A., and Crowley, J. N., "Cross-sections and Quantum Yields for the Atmospheric Photolysis of the Potent Greenhouse Gas Nitrogen Triflouride," Atmos. Environ., 44, 1186-1191 (2010). https://doi.org/10.1016/j.atmosenv.2009.12.026
  12. Kim, D. Y., and Park, D. W., "Decomposition of PFCs by Steam Plasma at Atmospheric Pressure," Surf. Coat. Tech., 202, 22-23 (2008).
  13. Narengerile, Saito, H., and Watanabe, T., "Decomposition of Tetraflouromethane by water Plasma Generated under Atmospheric Pressure," Thin Solid Films, 518, 929-935 (2009). https://doi.org/10.1016/j.tsf.2009.07.164
  14. Han, S. H., Park, H. W., Kim, T. H., and Park, D. W., "Large Scale Treatment of Perfluorocompounds Using a Thermal Plasma Scrubber," Clean Tech., 17, 250-258 (2011).
  15. Moreau, E., Chazelas, C., Mariaux, G., and Vardelle, A., "Modeling the Restrike Mode Operation of a DC Plasma Spray Torch," J. Thermal Spray Tech., 15, 524-530 (2006). https://doi.org/10.1361/105996306X147306

Cited by

  1. Treatment of Hydrogen Fluoride Generated from the F-gases Decomposition Processes vol.10, pp.4, 2016, https://doi.org/10.5572/ajae.2016.10.4.190
  2. A Study on Decomposition of Perfluorocompounds (NF3, CF4, SF6) Emitted from Semiconductor Process using Plasma vol.35, pp.3, 2018, https://doi.org/10.9786/kswm.2018.35.3.250