Thermodynamic analysis of Fe and Ni carbonyl formation in gasification

Oh, Myongsook S Research Institute for Science & Technology HONG-I 1997 Hongik Journal of Science and Technology Vol.1 No.-

The high pressure, high concentration of CO,and the temperatures of the carbon scrubber and the syngas coolers of the gasification process present favorable conditions for Ni(CO)₄and Fe(CO)? formation. Decomposition of these carbonyls was suspected for the deposit formation at downstream units. The thermodynamic equilibrium analysis was carried out to determine the optimum conditions for the formation and decomposition of Ni(CO)₄and Fe(CO)? For the Ni-rich feed such as heavy oil, a ppm level Ni(CO)₄was predicted. The concentration of Ni(CO)₄(g) increases at higher total concentrations of Ni, at higher concentrations of CO and H₂and at lower concentrations of H₂S. Even when Ni and Fe are co-present in the system, the Ni(CO)₄concentration is limited by the amount of Ni present in the system at low temperatures. However, a ppb level of Fe(Co)? was possible. With H₂S in the syngas, Fe in the system forms FeS, and the formation of Fe(CO)? is not thermodynamically analysis predicts the formatio of a ppm level Ni(CO)₄is possible, but not a ppm level Fe(CO)?

Slagging of petroleum coke ash using Korean anthracites

Woosung Park,Myongsook S. Oh 한국공업화학회 2008 Journal of Industrial and Engineering Chemistry Vol.14 No.3

Gasification of petroleum coke can present a problem with ash accumulation inside a gasifier because of the high melting temperature of V₂O₃. For slagging of V₂O₃ it was proposed to mix petroleum coke and Korean anthracite. The ash viscosities of two domestic anthracites (government reserve coal mix and Jangsung anthracite) were determined, along with the necessary flux concentrations. Both coal ashes had very high viscosities, and although both CaO and dolomite were effective in lowering the viscosity, dolomite was more effective than lime. V₂O₃ in coke ash remained solid at typical gasification temperatures, and the solid V₂O₃caused the slag viscosity to increase.Slag equilibrium calculations were carried out using FactSage. The difference between experimentally determined Tcv and Tliq predicted by FactSage was less than 20℃, when the accurate ash composition was provided, proving that Tcv can be estimated by Tliq. Using calculated Tliq, the amount of flux necessary was determined for a given minimum gasification temperature and coke:coal mixing ratio. In order to keep the flux concentration to a minimum, it is recommended to use a 90:10 mixture of coke:Jangsung coal with dolomite flux and to operate the gasifier at a temperature above 1370℃.

V₂O₃와 CaO의 농도에 따른 5-성분계 석유코크스 슬래그의 점도 변화

양윤정 ( Yoonjung Yang ),오명숙 ( Myongsook S. Oh ) 한국공업화학회 2020 공업화학 Vol.31 No.6

가스화 공정에서 원료 회분의 연속적인 제거를 위해 회분 성분에 따른 점도 거동뿐만 아니라, 온도가 낮아지면서 형성되는 결정체가 점도에 미치는 영향이 연구되어야 한다. 본 연구에서는 석유코크스 슬래그의 주성분 중 CaO와 V₂O₃성분의 변화에 따른 슬래그의 점도 거동과 결정 분석을 통해 이 두 성분이 석유코크스 슬래그 점도에 미치는 영향을 조사하였다. 각각의 함유량을 변화시키면서 약 1600 ℃부터 약 1100 ℃까지 온도를 낮추며 점도를 측정하였고, 냉각된시료의 결정상이 분석되었다. 측정된 시료는 대부분 결정형 점도 거동을 보여주었다. V₂O₃의 농도가 증가할수록 점도는 유리형에서 결정형으로 변화하였고, Tcv도 증가하는 경향을 보여주었다. CaO의 경우 농도가 증가할수록 낮은 점도와 낮은 Tcv를 보여주었다. 기준 시료를 포함한 모든 시료의 상, 중, 하부에서 다른 결정을 볼 수 있었다. 상, 중부에는 anorthite와 Ca-V 상이 관찰되었으면 하부에서는 주로 V₂O₃ 결정과 anorthite이 관찰되었다. 슬래그의 바나듐은 Ca-V상, V-Fe, 용융 슬래그 상을 형성한다. 융점이 낮은 Ca-V 상은 점도를 낮추는데 기여하는 것으로 보인다. Petroleum coke (petcoke) is widely used, next to coal, as a gasification feedstock. In gasification processes, the viscosity of the ash and the formation of crystalline phases must be understood to ensure the continuous removal of slag. This study investigates the effect of CaO and V₂O₃ on petcoke slag viscosity. The viscosity of the molten slag was measured in the temperature range of 1100~1600 ℃ while varying the concentration of each component. The crystalline phases formed in a cooled slag were examined. The most slag samples tested in this study exhibited crystalline slag behavior. The increased CaO concentration resulted in a lower viscosity and a lower Tcv. The viscosity behavior changed from the glassy to crystalline slag and also showed a higher Tcv as the concentration of V₂O₃ increases. Most slag samples showed different crystalline phases from top to bottom. Anorthites and Ca-V phases were observed in the top and middle section, while the bottom section mainly showed V₂O₃ and anorthite. The vanadium in the ash forms Ca-V and V-Fe phases and also remains in molten slag. A low melting Ca-V phase can contribute to lowering the viscosity.

Relative Quantitation of Major Organic Components in EMC by Pyrolysis-GC/MS

Park,Jung-Jin,Oh,Myongsook S. Research Institute for Science & Technology HONG- 1999 Hongik Journal of Science and Technology Vol.3 No.-

The TIC chromatograms of cured OCN-PN-TPP samples were analyzed for both qualitative and quantitative compositional analyses. The characteristic peaks representing OCN and PN were selected. and the ratio of relative peak intensities was related to the mass ratio of OCN/PN. The cured OCN-PN-TPP system showed six distinct peaks, of which two were representative of PN and two of OCN. The intensities of these peaks varied with the changing relative composition of OCN to PN. When the intensity ratio of the peaks representing PN and OCN was related to the OCN/PN weight ratio, a linear relationship was observed, even though there was some scatter in the data. The scatter, in part, is caused by varying concentrations of TPP: at a given weight ratio of OCN/PN, a high TPP concentration results in an increase in the peak ratio. A model relating the peak ratio as a function of the mass ratios of OCN/PN and TPP/PN was proposed. The model has three fitted parameters derived form the data, and the model test proves that an estimate of the OCN/PN ratio can be obtained from the peak intensities in the Py-GC/MS chromatogram.

크롬계 내화물에서 슬래그의 산화철 농도가 (Fe,Cr)₃O₄ 형성에 미치는 영향

박우성,오명숙,Park, Woo Sung,Oh, Myongsook S. 한국공업화학회 2007 공업화학 Vol.18 No.5

석탄가스화기의 내벽은 내화물로 구성되어 있다. 내화물의 침식은 가스화기 내화물의 수명 및 교체시기에 영향을 미치는 중요한 인자이다. 본 논문에서는 슬래그와의 반응에 의한 내화재의 미세구조의 변화를 침식화합물의 형성에 가장 큰 영향을 미치는 산화철 농도의 함수로 조사하였다. 산화철 농도가 낮은 KIDECO 탄 슬래그에 산화철을 첨가하여 정적 침식실험을 수행한 후 $(Fe,Cr)_3O_4$의 형성과 침투 슬래그에서의 Fe의 고갈 깊이를 측정하였다. 그리고 FactSage를 이용한 평형계산을 통하여 chromite 형성조건을 조사하고 실험 결과와 비교하였다. 고정된 온도인 $1550^{\circ}C$에서 약 10%의 산화철을 포함한 KIDECO 슬래그에서는 $(Fe,Cr)_3O_4$의 형성이 관찰되지 않았으나 산화철의 함량이 증가될수록 $(Fe,Cr)_3O_4$ 형성이 관찰되었으며, 경계면의 $(Fe,Cr)_3O_4$ 층의 두께가 증가하였고, 산화철의 고갈 깊이도 증가하였다. 또한 산화철의 양이 많아질수록 화학적 침식이 증가하면서 슬래그와 내화물의 경계가 모호해지는 것을 확인하였다. 슬래그-내화재 계의 평형계산은 슬래그의 산화철 농도가 증가할수록 가스화기 조업온도에서 chromite 형성 가능성이 높아짐을 보여주었다, 또한 내화물이 슬래그에 용해된 경우와 같이 $Cr_2O_3$가 낮은 농도로 존재할 때 chromite 형성이 가장 유리하였고, 산화철의 농도가 20% 이하에서는 슬래그와 내화물이 같은 양으로 존재하는 경우가 chromite 형성에 가장 불리하였다. The inside wall of a coal gasifier is lined with refractory, and the corrosion of the refractory is an important factor affecting the refractory lifetime and the replacement period. This paper examines the changes in microstructure of a chromia refractory due to chemical reactions with slag having varying amounts of $Fe_2O_3$. Slag samples were prepared by adding $Fe_2O_3$ to KIDECO slag, and static corrosion experiments were carried out at $1550^{\circ}C$. The layer of $(Fe,Cr)_3O_4$ formation and the depth of Fe depletion in the infiltrating slag were determined. In addition, FactSage equilibrium calculations were carried out in order to determine the conditions of formation, and to compare with the experimental observations. In the sample exposed to KIDECO slag, which has about 10 wt% $Fe_2O_3$, the formation of $(Fe,Cr)_3O_4$ was not observed. As the $Fe_2O_3$ concentration in slag increased, $(Fe,Cr)_3O_4$ formation and Fe depletion depth increased. Increasing $Fe_2O_3$ concentration also made the slag/refractory interface indistinguishable. Equilibrium calculations predicted that higher $Fe_2O_3$ concentrations favor chromite formation at gasification temperatures. The chromite formation was most favorable when the amount of $Cr_2O_3$ was limited, as in the case of dissolved $Cr_2O_3$ in slag. When the concentration of $Fe_2O_3$ in slag was less than 20%, the formation of chromite was least favorable in the system with equal amounts of slag and refractory.

여학생의 젠더 실천을 통해 본 공학교육 공동체의 젠더

김원정(Kim, Wonjung),정유진(Chong, Youjin),오명숙(Myongsook S. Oh) 한국여성학회 2015 한국여성학 Vol.31 No.3

본 연구는 H대 공과대학 여학생들의 초점집단면접 자료를 바탕으로 공대 여학생의 젠더 실천과 정체성 관리 작업을 분석하고, 이를 통해 오늘날 공학교육 공동체의 젠더 관계를 들여다보았다. 학습활동과 자치활동, 이성교제 등 다양한 상호작용에서 여학생들은 주어진 맥락에 따라 젠더 중립성을 주장하거나 여성(성)과 거리를 두는가 하면 전형적인 여성성을 수행하기도 하는, 상이한 패턴의 젠더 실천들을 병행하였고, 평판 관리를 위해 여성성을 전략적으로 활용하는 모습을 보이기도 했다. 이는 공동체에 존재하는 여성성에 대한 모순된 기대와 압력을 반증하는 것으로, 그로 인한 긴장이 가장 증폭되는 외모 꾸미기와 이성교제에서 여성성을 비/가시화하는 여학생들의 유연한 관리는 더욱 두드러졌다. 여성이자 공대생 되기를 시도하는 여학생들의 능동적인 젠더 실천들을 긍정적으로 조명하면서도, 본 연구는 그것이 공대-남성의 공고한 연결을 해체하는 데 기여하지는 못했다고 평가했다. 공학교육 공동체에서 지배적인 젠더 질서의 전환은 여전히 더디며 현재 한국사회의 젠더 담론 지형에서 그러한 시도가 더욱 지체될 수 있다는 것이 본 연구의 진단이다. 이러한 결론에 이어 전환의 시도를 자극할 수 있는 몇 가지 실천의 방향을 제안한다. The purpose of this study lies in diagnosing gender relations in engineering school today by analyzing gender practices and identity construction of women students in colleges of engineering. According to the results of analysis, women students simultaneously engaged in disparate gender practices including an emphasis on gender neutrality, distancing themselves from women/femininity, and doing typical femininity in accordance with the given context. This shows contradictory pressure on women that exists within the engineering educational community. Especially in dress or dating, women students manage their in/visibility of feminity more flexibly. While positively highlighting women students’ active and multifaceted gender practicing, the study points out that the transformation of the dominant gender order within colleges of engineering still remains slow and that claiming gender neutrality has delayed the process even further by interfering with the recognition of structural gender issues. Finally, we propose some ways of practices that stimulate transformational attempts for change of gender relations.