Journal of the Korea Academia-Industrial cooperation Society (한국산학기술학회논문지)

The Korea Academia-Industrial cooperation Society (한국산학기술학회)
권호 표지
DOI QR코드

DOI QR Code

Experimental Study on Corrosion Characteristics of 1.25Cr-0.5Mo in the 1st-mathanator reactor for Synthetic Natural Gas according to Gas Compositions

1.25Cr-0.5Mo강을 이용한 합성가스 조성 변화에 따른 SNG 1차반응기의 부식특성에 관한 실험적 연구

  • Kim, Jin-Hyun (Department of Automobiles, Chosun College University of Science & Technology) ;
  • Cho, Honghyun (Department of Mechanical engineering, Chosun University)
  • Received : 2016.04.12
  • Accepted : 2016.05.12
  • Published : 2016.05.31
Download PDF
⟨ Previous Next ⟩

Abstract

Recently, the operating conditions of the various mechanical structures have become more severe and the running time has become longer as the development of plant equipment increases with the introduction of high technology. Thus, the reliability of the system and its accessories is becoming a problem. Normally, synthetic natural gas (SNG) plants use 1.25Cr-0.5Mo or 2.25Cr-1Mo heat resistant steel according to the operating conditions. In this study, a lab-scale reactor was set up using 1.25Cr-0.5Mo steel, in order to carry out corrosion tests for producing synthetic natural gas. The corrosive characteristics were investigated under 1st-methanator operating conditions and fundamental data about the durability and reliability were obtained by using the experimental test. The analysis of results obtained on the durability of the reactor under emission and injection compositions showed that the hydrogen embrittlement caused by hydrogen and the oxidation corrosion caused by H2O had the most effect on the durability of 1.25Cr-0.5Mo steel in the SNG reactor. However, the hydrogen embrittlement and oxidation corrosion occurred simultaneously under emission conditions, so that the corrosion of the material increased suddenly after a long operating time. Besides, the corrosion of the 1.25Cr-0.5Mo steel under the injection composition was faster than that under the emission composition.

최근 급속한 플랜트 설비의 발전과 더불어 각종 기계 구조물들의 운전조건이 가혹해지고 사용시간이 길어짐에 따라 신뢰성에 대한 문제가 제기되고 있다. 특히, SNG 설비에 사용되는 재료는 설계조건에 따라 1.25Cr-0.5Mo 또는 2.25Cr-1Mo강과 같은 내열강들이 주로 사용된다. 본 연구에서는 Lab-scale용 합성천연가스 반응기를 제작하여 생산공정 반응기 재질인 1.25Cr-0.5Mo강을 이용하여 실제 SNG 공정중 1차반응기와 동일한 운전 조건에서 부식 특성에 대하여 실험적 연구를 진행하였다. 1.25Cr-0.5Mo강을 운전 시간에 따라 각각 배출조성 조건과 주입조성 조건에 노출시켜 부식에 대한 실험을 수행하였으며 실험 결과 내구성에 가장 영향을 미치는 요소는 수소로 인한 수소취성과 산화 부식임을 알 수 있었으며, 배출조성보다 주입조성에서 더 빠른 부식이 발생함을 확인하였다. 그러나 배출조성 조건에서는 산화부식과 더불어 수소취성에 의한 부식이 동시에 발생하여 장시간 운전 후 부식정도가 갑자기 증가하고 부식강도가 급격히 강해지는 것을 나타났다. 또한 주입조성에서는 산화물들이 시편에 흡착되어 두꺼운 산화층을 형성시켰으며 이로 인하여 재료의 내산화성이 크게 저하되는 것으로 확인되었다.

Keywords

References

  1. H. J. Kim, H. S. Ryoo, "Ways to Improve Reliability against Stress-Relief Cracking in Weld Metal", Trans. of KMSE, Vol.25, No.2, pp. 3-5, 2007.
  2. H. J. Sung, M. S. Ju, J. G. Ju, Y. Y. Kim, "Characteristics of Electro Slag Strip overlaied weldments on the 1.25Cr-0.5Mo Steel", KWJS Conference, Vol. 45, pp. 65-66, 2005.
  3. D. H. Lee, J. J. Pack, "Effect of Welding Heat Input and PWHT Cooling Rate on Mechanical Properties of Welded Region at SAW of 1.25Cr-0.5Mo Steel for Pressure Vessel", KWJS Vol.22, No.5 pp. 26-31, 2004.
  4. H. W. Lee, H. T. Yang, S. T. Kim, "The Characteristics of the Hydrogen Embrittlement for the Cr-Mo Steels in Use of Pressure Vessel", Trans. of KSME A, Vol.26, No. 6, pp. 1107-1113, 2002. https://doi.org/10.3795/KSME-A.2002.26.6.1107
  5. K. D. Park, J. H. Kim, H. K. Yoon, W. J. Park, "Evaluation on High Temperature Fracture Toughness of Pressure Vessel SA516/70 Steel", ISSN, 1225-0767, pp. 99-104, 2001
  6. J. H. Yun, B. S. Lee, Y. J. Oh, J. W. Kim, J. H. Hong, "Effects of temperature and loading rate about fracture resistance of SA518-Gr.70, Nuclear Reactor Coolant pipe", KMS Conference, 1998.
  7. Y. D. Yoo, S. H. Kim, Y. S. Yun, G. T. Jin, "Conversion Technology from Coal to Synthetic Natural Gas", Korean Industrial Chemistry News, Vol. 12, No.3, pp. 38-57, 2009.
  8. H. T. Yang, S. T. Kim, "A Study on the Mechanical Properties and Microstructural Change by the Thermal Embrittlement of Cr-Mo Steel", Proceeding of the KAMES 2002 Joint Symposium, Vol. 2002, No. 11, pp. 65-70, 2002.
  9. G. G. Hancock, H. H. Johnson, Transactions of Metallurgical Society of AIME, 236, pp. 513-514, 1966
  10. C. A. Zapffe, C. E. Sims, "Hydrogen Embrittlement, internal stress and defects in steel", Trans. AIME, 145, pp. 225-226. 1941.
  11. A. S. Tetelman, Hydrogen in Metals, ASM 17, 1974
  12. H. T. Yang, S. T. Kim, "A Study on the Mechanical strength change by thermal aging of 2.25Cr-1Mo steel", Transactions of the Korean Society of Mechanical Engineers A Vol.24 No. 7, 1771-1778, 2000. https://doi.org/10.22634/KSME-A.2000.24.7.1771
  13. S. G. Lee, M. H. Chung, S. K. Oh, J. K. Song, "Creep property Assessment and Creep Life Estimation for High-Remperature Tube Material(2.25Cr1Mo Steel) in Power Plants by LMP", JOET, Vol. 12, No.2, pp. 65-70, 1998.
  14. C. F. Barth, E. A. Steigerwald, A. R. Troiano, "Hydrogen Permeability and Delayed Failure of Polarized Martensitic Steels", Corrosion, 25(9), pp. 353-358, 1969. https://doi.org/10.5006/0010-9312-25.9.353
  15. B. E. Wilde, "Mechanism of Cracking of High Strength Martensitic Stainless Steels in Sodium Chloride Solution", Corrosion, 27(8), pp. 326-333, 1971. https://doi.org/10.5006/0010-9312-27.8.326
  16. I. C. Choi, K. M. Lee, "Combustion Characteristics of Dual Swirl Combustor according to Hydrogen Content in Simulated SNG Fuel", KOSCO SYMPOSIUM, pp. 111-113, 2014.
  17. M. J. Kim, S. W. Chung, J. E. Lee, D. B.Lee, "The Society Of Air-Conditioning And Refrigerating Engineers Of Korea", SAREK SYMPOSIUM, pp. 780-784, 2014.
  18. T. W. Kang, K. S. Yoon, M. S. Yang, J. K. Kim, S. H. Kim, "Synthetic natural gas(SNG) production facility construction projects for the pre-feasibility study", Yooshin technical article, Vol. 19, No.4, pp. 34-47, 2012.