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Power-to-Gas 플랜트 연계 순산소 연소 보일러 공정 해석
손근(Geun Sohn),류주열(Ju-Yeol Ryu),박혜민(Hye-Min Park),박성호(Sung-Ho Park) 한국열환경공학회 2021 열환경공학 Vol.16 No.1
Power-to-Gas(PtG) is a promising technology that produces hydrogen by the electrochemical reaction in water electrolyzer to manage the intermittent power generation from renewable energy such as wind and solar. Water electrolyzer generates hydrogen and highly purified oxygen as a by-product. In this study, the process was examined in coal fired oxy-fuel combustion power plant and in PtG plant to use highly purified oxygen obtained from water electrolyzer. The power generation efficiency of a coal-fired oxy-fuel power plant supplied with oxygen through an air separation unit and that of a coal-fired oxy-fuel power plant supplied with oxygen in a polymer electrolyte membrane (PEM) water electrolysis process were compared. As a result of the analysis, in the case of the combined system of the coal-fired oxy-fuel power plant and the PtG plant, the net power generation and power generation efficiency were higher than the case of individual coal-fired oxy-fuel power plant supplied with oxygen through the air separation unit. The process efficiency is further improved when using biomass, fueling the oxy-fuel combustion boiler rather than coal and when steam-water is in supercritical conditions.
가압 DTF를 이용한 석탄 촤-CO₂ 가스화 반응상수 도출
손근(Geun Sohn),예인수(Insoo Ye),라호원(Howon Ra),윤성민(Sungmin Yoon),류창국(Changkook Ryu) 한국연소학회 2017 한국연소학회지 Vol.22 No.4
This study investigates the gasification of coal char by CO₂ under high pressures in a drop tube furnace(DTF). The rate constants are derived for the shrinking core model using the conventional method based on the set reactor conditions. The computational fluid dynamic(CFD) simulations adopting the rate constants revealed that the carbon conversion was much slower than the experimental results, especially under high temperature and high partial pressure of reactants. Three reasons were identified for the discrepancy: i) shorter reaction time because of the entry region for heating, ii) lower particle temperature by the endothermic reaction, and iii) lower partial pressure of CO₂ by its consumption. Therefore, the rate constants were corrected based on the actual reaction conditions of the char. The CFD results updated using the corrected rate constants well matched with the measured values. Such correction of reaction conditions in a DTF is essential in deriving rate constants for any char conversion models by H₂O and O₂ as well as CO₂.
석탄가스화기 내 버너 이상거동에 따른 유동 및 반응특성에 대한 전산해석 연구
남준영(Joonyeong Nam),김무경(Mukyeong Kim),손근(Geun Sohn),류창국(Changkook Ryu),김봉근(Bonggeun Kim) 한국연소학회 2019 KOSCOSYMPOSIUM논문집 Vol.2019 No.11
In a Shell coal gasifier, four horizontally biased coal burners located in the middle of a cylindrical reactor creats a swirling flow at the center that governs the flow and particle behaviors. If the coal burners do not have the identical fuel and oxidant throughput by operational issues or during startup and shutdown, this breaks the axisymmetry of the swirling flow. In this study, the influence of abnormal burner operation was investigated using computational fluid dynamics (CFD) for the coal gasifier empolyed at Taean 300 MWe plant. It was found that the changes in the fuel or oxidant throughput in one burner by 30% can significantly shift the how swirling flow to the wall, creating a region of excessive heat flux to the wall (hot spot). Maintaining the axisymmetry by adjusting one burner pair to the same condition can alleviate this issue. If burners are inevitably to be turned off, the three-burner opeation was better than two-burner operation in terms of the peak heat flux in the hot spots.