1.25Cr-0.5Mo 강을이용한합성가스조성변화에따른 SNG 1 차반응기의부식특성에관한실험적연구 김진현 1, 조홍현 2* 1 조선이공대학교자동차과, 2 조선대학교기계공학과 Experimental Study on Corrosion Characteristics of 1.25Cr-0.5Mo in the 1 st -mathanator reactor for Synthetic Natural Gas according to Gas Compositions Jin-Hyun Kim 1, Honghyun Cho 2* 1 Department of Automobiles, Chosun College University of Science & Technology, 2 Department of Mechanical engineering, Chosun University 요약최근급속한플랜트설비의발전과더불어각종기계구조물들의운전조건이가혹해지고사용시간이길어짐에따라신뢰성에대한문제가제기되고있다. 특히, SNG 설비에사용되는재료는설계조건에따라 1.25Cr-0.5Mo 또는 2.25Cr-1Mo강과같은내열강들이주로사용된다. 본연구에서는 Lab-scale용합성천연가스반응기를제작하여생산공정반응기재질인 1.25Cr-0.5Mo강을이용하여실제 SNG 공정중 1차반응기와동일한운전조건에서부식특성에대하여실험적연구를진행하였다. 1.25Cr-0.5Mo강을운전시간에따라각각배출조성조건과주입조성조건에노출시켜부식에대한실험을수행하였으며실험결과내구성에가장영향을미치는요소는수소로인한수소취성과산화부식임을알수있었으며, 배출조성보다주입조성에서더빠른부식이발생함을확인하였다. 그러나배출조성조건에서는산화부식과더불어수소취성에의한부식이동시에발생하여장시간운전후부식정도가갑자기증가하고부식강도가급격히강해지는것을나타났다. 또한주입조성에서는산화물들이시편에흡착되어두꺼운산화층을형성시켰으며이로인하여재료의내산화성이크게저하되는것으로확인되었다. 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. Keywords : Synthetic natural gas(sng), 1.25Cr-0.5Mo, 1 st -Methanator, Composition, CorrosionCorresponding Author : Honghyun Cho(Chosun University) Tel: +82-62-230-7050 email: hhcho@chosun.ac.kr Received April 12, 2016 Revised May 11, 2016 Accepted May 12, 2016 Published May 31, 2016
Journal of the Korea Academia-Industrial cooperation Society Vol. 17, No. 5 pp. 709-716, 2016 http://dx.doi.org/10.5762/kais.2016.17.5.709 ISSN 1975-4701 / eissn 2288-4688 1. 서론 SNG, Table 1. SNG,,, H 2 /CO, Conventional shift and methanation Combined shift and methanation. SNG SNG CO 2. Table 1. Synthetic natural gas process Process Gasification based process for producing Hydrogasification based process for producing Catalyst gasification based process for producing (Hydromethanation) Characteristic Main response : CO + 3H 2 CH 4 + H 2O The commercialization process Main response : C + 2H 2 CH 4 Do not commercialization process Main response : 2C + 2H 2O CH 4 + CO 2 Do not commercialization process,,..,,,,., EU (1-3)., 300 600. 1 400. 709
한국산학기술학회논문지제 17 권제 5 호, 2016 (4-8). Hancock (9) (Fe),. Zapffe (10) (void).. Tetelman (11)., Yang (12)., Lee (13) (2.25Cr-1Mo). Barth (13-14),. Choi (15). Kim (17) (IGCC). SNG SNG.. Lab-scale SNG 1 (1.25Cr-0.5Mo) (400, 4.4 MPa). 2. 실험장치및조건 2.1 실험장치설명 Fig. 1,,.,,. (back pressure regulator) 2%. 1%. 710
1.25Cr-0.5Mo 강을이용한합성가스조성변화에따른 SNG 1 차반응기의부식특성에관한실험적연구 Fig. 1. Schematics of the experimental setup 2.2 실험방법및조건 SNG 18 1,. A387 Grade 11 Alloy(1.25Cr-0.5Mo), Table 2.. (N 2 /CH 4 /CO/H 2 ; ) (CO 2 /N 2 /CH 4 /CO/H 2 ; ). Table 3.,, CO 2. CO 2 CO 2 Table 3 CO 2. 1 400, 4.4 MPa 1.25Cr-0.5Mo Lab-scale 10,080, 80,064 161,280.,, (mounting) SiC 2,000, SEM-EDS(scanning electron microcope energy dispersive x-ray spectroscopy) (i-speed, Olympus). Table 2. Chemical composition of a 1.25Cr-0.5Mo steel(wt.%) 1.25Cr-0.5Mo(A387 Grade 11) C Si Mn P S Cr Mo 0.05 0.17 0.50 0.80 0.40 0.65 0.035 0.035 1.00 1.50 0.45 0.60 711
한국산학기술학회논문지제 17 권제 5 호, 2016 Table 3. Composition of injection and emission synthetic gas in the reactor(mol%) Injection Emission CO 2 N 2 CH 4 CO H 2 0.50 0.52 6.14 22.35 Balance CO H 2 CH 4 N 2 0.20 12.38 39.27 Balance 3. 실험결과및고찰 Fig. 2 3 1 400, 4.4 MPa 10,080. SEM 1.2 2 um. Fig. 3 80,640 2 4 um, 10,080. Fig. 4 161,280 8 um 80,640 2..,.,. Fig. 2. SEM fractographs of 1.25Cr-0.5Mo under injection composition for 10,080 minutes 712
1.25Cr-0.5Mo 강을이용한합성가스조성변화에따른 SNG 1 차반응기의부식특성에관한실험적연구 Fig. 3. SEM fractographs of 1.25Cr-0.5Mo under injection composition for 80,640 minutes Fig. 4. SEM fractographs of 1.25Cr-0.5Mo under injection composition for 161,280 minutes Fig. 5 400, 4.4 MPa 10,080 SEM... 713
한국산학기술학회논문지제 17 권제 5 호, 2016.,. Fig. 6 80,640. 10,080 O 11.63wt%.. Fig. 5. SEM fractographs of 1.25Cr-0.5Mo under emission composition for 10,080 minutes 714
1.25Cr-0.5Mo 강을이용한합성가스조성변화에따른 SNG 1 차반응기의부식특성에관한실험적연구 Fig. 6. SEM fractographs of 1.25Cr-0.5Mo under emission composition for 80,640 minutes Fig. 7 161,280 80,640. SNG.,. 1 SNG 1. Fig. 7. SEM fractographs of 1.25Cr-0.5Mo under emission composition for 161,280 minutes Fig. 8. 10,080. 715
한국산학기술학회논문지제 17 권제 5 호, 2016, 10,080.. 10,080, 161,280 333 mg... Fig. 8. 1.25Cr-0.5Mo fracture under injection composition Fig. 9. 80,640 0.02 mg 161,280 3.6 mg.. 80,640. 673 mg 161,280 210 mg 883 mg... Fig. 9. 1.25Cr-0.5Mo fracture under emission composition 716
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