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고온 이산화탄소 분위기에서 316 L 스테인리스강의 부식 거동
채호병,서석호,정용찬,이수열,Chae, Hobyung,Seo, Sukho,Jung, Yong Chan,Lee, Soo Yeol 한국재료학회 2017 한국재료학회지 Vol.27 No.10
Evaluation of the durability and stability of materials used in power plants is of great importance because parts or components for turbines, heat exchangers and compressors are often exposed to extreme environments such as high temperature and pressure. In this work, high-temperature corrosion behavior of 316 L stainless steel in a carbon dioxide environment was studied to examine the applicability of a material for a supercritical carbon dioxide Brayton cycle as the next generation power plant system. The specimens were exposed in a high-purity carbon dioxide environment at temperatures ranging from 500 to $800^{\circ}C$ during 1000 hours. The features of the corroded products were examined by optical microscope and scanning electron microscope, and the chemical compound was determined by x-ray photoelectron spectroscopy. The results show that while the 316 L stainless steel had good corrosion resistance in the range of $500-700^{\circ}C$ in the carbon dioxide environment, the corrosion resistance at $800^{\circ}C$ was very poor due to chipping the corroded products off, which resulted in a considerable loss in weight.
채호병,서석호,정용찬,이수열,Chae, Hobyung,Seo, Sukho,Jung, Yong Chan,Lee, Soo Yeol 한국전력공사 2015 KEPCO Journal on electric power and energy Vol.1 No.1
초임계 이산화탄소 발전 시스템 구축을 위해서는 고온, 고압의 열악한 환경에 노출되는 터빈, 열 교환기, 압축기와 같은 핵심 부품들의 내식성 평가는 반드시 수행되어야 한다. 이를 위해 후보소재 3종 Ferritic-Martensitic Steel (T92), Austenitic Steel (SS316L), Ni-based Alloy (IN738LC)를 선정하여 고온의 유사 초임계 $CO_2$ 발전 환경에서의 내식성 평가를 진행하였다. $600^{\circ}C$, $700^{\circ}C$의 2개의 온도 구간에서 $CO_2$ 분위기를 조성하여 800 시간 동안 노출시킨 뒤, Weight Change, Surface Morphology, Cross Section, Composition을 분석하였다. Cr-rich Protective Layer를 형성하는 Ni-based Alloy와 Fe/Cr-rich oxide를 형성하는 Austenitic Steel은 우수한 부식 저항성을 보인 반면에 Ferritic-Martensitic Steel은 높은 Weight Change와 Fe-rich Non-Protective Oxide가 관찰되어 상대적으로 낮은 부식 저항성을 보였다.
채호병 ( Hobyung Chae ),김우철 ( Woo Cheol Kim ),김희산 ( Heesan Kim ),김정구 ( Jung-gu Kim ),김경민 ( Kyung Min Kim ),이수열 ( Soo Yeol Lee ) 한국부식방식학회(구 한국부식학회) 2021 Corrosion Science and Technology Vol.20 No.2
In this work, we have performed a corrosion failure analysis of a leaking tube connected to an upper header of a condensate pre-heater in a heat recovery steam generator. It was revealed that the leakage position in the tube was the location where the materials were easily vulnerable due to tensile residual stresses induced by the material manufacturing process and welding process. In addition to an imbalance in the module induced by temperature difference during operation of the pre-heater, the weight of the modules and thermal fatigue provoked a type of stress of tensile-tensile fatigue on the tube. Thus, the leakage position of the pre-heater was exposed to the tensile stress on the inner surface of the tube facing the gas, which rendered the unstable oxide layer susceptible to corrosion and the formation of pits on the water side. The cracks propagated along with the degraded microstructure in a transgranular cracking mode under fatigue loading and finally resulted in water leakage.
CFD에 기반한 벽체형 공기식 BIPVT의 열 및 전기 효율 분석
채호병(Hobyung Chae),배상무(Sangmu Bae),오진환(Jinhwan Oh),남유진(Yujin Nam) 대한설비공학회 2024 설비공학논문집 Vol.36 No.6
This paper provides foundational research into enhancing a building-integrated photovoltaic/thermal (BIPVT) system, focusing on predicting performance by examining the configuration of heat exchangers and flow rates in an air-based BIPVT system. Numerical analysis software (Ansys Fluent) was employed to calculate heat gain and PV efficiency under defined conditions: insulated sides of the BIPVT, a steady back panel temperature aligned with the building wall temperature (25℃), and maximal solar irradiance (1,000 W/m2) in steady-state scenarios. The findings indicate that PV cell temperature increases with greater internal fin spacing of heat exchangers and decreased flow rate. Conversely, the outlet temperature decreases with an increased flow rate. The efficiency of the PV system varied between 10.5% and 12.2%, with heat gain values ranging from 54.4 to 254.4 W/m². The pressure loss within the system ranged from approximately 3.9 to 27.8 Pa across a flow rate spectrum of 0.2 to 0.9 kg/s, demonstrating a linear increase with the flow rate. Additionally, variations in pressure loss based on fin spacing resulted in a reduction of approximately 67.3% in Case 2 and 48.0% in Case 3 compared to Case 1.