KS C 8569 기반의 연료전지시스템 성능평가 및 그 운영에 관한 고찰

차정은(Jung-Eun Cha),이남진(Nam Jin Lee),최영우(Young-Woo Choi),윤영기(Young Ki Yoon),김원배(Won Bae Kim) 대한기계학회 2021 대한기계학회 춘추학술대회 Vol.2021 No.4

연료전지는 수소와 산소로부터 전기화학 반응을 통해 직접 전기를 생산하는 발전장치로, 연료전지 시스템은 연료전지 스택, 연료변환기, 주변기기(MBOP: Mechanical Balance of Plant, EBOP: Electrical Balance of Plant) 및 제어기술을 포함한다. 연료전지 보급이 확대되면서, 안전과 성능 검증을 위한 표준이 요구되었으며, 이에 따라 표준서 KS C 8569는 2015 년 고분자연료전지(PEMFC) 시스템에 대하여 KS 제정을 시작으로 2019 년에는 직접 메탄올 연료전지(DMFC)시스템을, 2020 년에는 고체고분자연료전지(SOFC)시스템을 포함함으로써 현재의 표준서가 완성되었다. KS C 8569는 발전효율, 열효율, 기동/정지 특성, 부하변동 등을 포함하는 성능평가와 온도상승, 절연, 계통 보호, 내전기환경시험 등의 안정성 평가, 그리고 배출가스, 소음측정 등 환경성 평가로 구분되며, 총 49 개 상세항목으로 구성되어 있다. 초반 4 개 기업의 정지형, 즉 건물용 PEMFC 연료전지시스템의 KS 인증을 시작으로 현재 SOFC까지 포함하여 13 여개 기업으로 확장되었다. 또한, 초반에 1 kW 급 이하의 시스템이 대부분이었으나 2017 년 이후부터는 5 kW이상, 최근에는 10 kW 시스템이 주력을 이루고 있다. 하지만, 지금의 표준서는 기존의 정지형에서 이동형을 결합한 것으로 평가내용이 혼재되고, 이동형의 기본성능 (직류), 내열, 충격, 진동, 냉온 등의 안전성 검사 기준이 미흡하다. 또한, 정지형의 경우 10kW 급 이하로 규정되어 있어서 100 kW 이하의 과도기적인 시장 제품에 적합하지 못하다. 따라서, KS C 8569를 재정비하고, 국제표준과의 부합화를 통하여 국내 연료전지 산업 육성과 더불어 수출전략 고도화 가능성을 모색해야한다. The fuel cell is one of the power generating systems converting the chemical energy of hydrogen and oxygen into electricity through a pair of redox reactions, which mainly consists of a fuel reformer, cell stack, and an inverter. With the expansion of the supply of fuel cell systems, test standards and certifications have been required to verify the safety and performance of fuel cells. Starting with KS certification for polymer electrolyte membrane fuel cell (PEMFC) systems in 2015, KS C 8569 has been completed by including direct methanol fuel cell (DMFC) systems in 2019 and solid oxide fuel cell (SOFC) systems in 2020. This certification is divided into the performance assessment including power generation efficiency, thermal efficiency, start-up/shut-down characteristics, stability evaluation for the increase in temperature, electric resistance test, and the environmental assessment such as emissions and noise measurements. Initially, four fuel cell system manufacturers obtained KS certification for the stationary system, and now it has been expanded to a total of 13 companies including SOFC and DMFC system manufacturing companies. Besides, most of the systems were 1 kW or lower in the beginning, however since 2017, the capacity has increased to 5 kW or higher, and 10 kW systems have recently become the main focus. However, this standard has been revised to add the mobile fuel cell system standard to the existing stationary fuel cell standard, which lacks basic performance (direct current), heat resistance, shock, vibration, cold and hot tests that conform to the mobile fuel cell system standard. In addition, stationary fuel cell systems are not suitable for transition market products under 100 kW because they are defined as less than 10 kW. Accordingly, KS C 8569 should be reviewed to suit international standards and transitional market products to promote the domestic fuel cell industry and seek the possibility of upgrading its export strategy.

Numerical investigation for effect of fuel utilization on reversible solid oxide cell

이승주,이성철 한국공업화학회 2016 한국공업화학회 연구논문 초록집 Vol.2016 No.1

Reversible solid oxide cells (RSOCs) have been developed to use as an energy storage device in which energy is stored by solid oxide electrolysis cell (SOEC) operation and released by solid oxide fuel cell (SOFC) operation. In RSOCs, fuel utilization is controlled by the flow rate of fuel and air to the cell. Increasing the fuel flow rate leads to decrease in the fuel utilization and uniform distribution of the reactant at the reaction area. On the other hand, decreasing the fuel flow rate leads to increase in the fuel utilization and the reactant depletion. In this work, we investigated a RSOC numerically using a computational fluid dynamics (CFD) method to predict the effect of fuel utilization on the SOFC and SOEC operations. In parametric study, the current-voltage curves were estimated with respect to the variation of the flow rate. The results show the trade-off between the fuel utilization and the cell efficiency.

저온 작동 박막 고체산화물 연료전지

Shim, Joon-H.,Cha, Suk-Won,Gur, Turgut M.,Prinz Fritz B. 한국세라믹학회 2006 한국세라믹학회지 Vol.43 No.12

Recently, a new type of solid oxide fuel cells has been developed employing extremely thin oxide electrolyte. These fuel cells are expected to operate at significantly reduced temperature compared to conventional solid oxide fuel cells. Accordingly, they may resolve the stability and material selection issues of high temperature fuel cells. Furthermore, they may eliminate the limitations of polymer membrane fuel cells whose operation temperature is under $100^{\circ}C$. In this paper, we review the electrolytes for intermediate temperature operation. Then, we discuss the current development of thin film solid oxide fuel cells that possibly operated at low temperatures.

Characterization of novel Ba₂LnMoO₆ (Ln = Pr and Nd) double perovskite as the anode material for hydrocarbon-fueled solid oxide fuel cells

Rath, Manasa K.,Lee, Ki-Tae Elsevier 2018 JOURNAL OF ALLOYS AND COMPOUNDS Vol.737 No.-

<P><B>Abstract</B></P> <P>Ba<SUB>2</SUB>LnMoO<SUB>6</SUB> (Ln = Pr and Nd), with a double perovskite structure, has been investigated as an efficient anode material for solid oxide fuel cells (SOFCs) operating under methane fuel. Ba<SUB>2</SUB>LnMoO<SUB>6</SUB> (Ln = Pr and Nd) powders were successfully synthesized by a citric acid ethylene-diamine-tetraacetic acid (CA-EDTA) combustion technique. Ba<SUB>2</SUB>LnMoO<SUB>6</SUB> (Ln = Pr and Nd) was thermally and morphologically stable at high temperature and chemically compatible with the Gd<SUB>0.2</SUB>Ce<SUB>0.8</SUB>O<SUB>1.8</SUB> (GDC) electrolyte. The electrical conductivities of Ba<SUB>2</SUB>PrMoO<SUB>6</SUB> and Ba<SUB>2</SUB>NdMoO<SUB>6</SUB> were 348.5 and 146 Scm<SUP>−1</SUP> under humidified CH<SUB>4</SUB> at 800 °C, respectively. However, Ba<SUB>2</SUB>LnMoO<SUB>6</SUB> (Ln = Pr and Nd) exhibits better catalytic activity for the hydrogen oxidation reaction (HOR) than for the methane oxidation reaction (MOR); this is due to the presence of deposited carbon, which blocks the fuel path during the overall methane oxidation process.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Ba<SUB>2</SUB>LnMoO<SUB>6</SUB> (Ln = Pr and Nd) reduce in 5%H<SUB>2</SUB>/Ar has cubic double perovskite structure. </LI> <LI> Ba<SUB>2</SUB>PrMoO<SUB>6</SUB> exhibits high conductivity of 348.5 Scm<SUP>−1</SUP> under wet CH<SUB>4</SUB> at 800 °C. </LI> <LI> High conductivity under wet CH<SUB>4</SUB> is correlated with the carbon deposition. </LI> <LI> Activation energy of Ba<SUB>2</SUB>PrMoO<SUB>6</SUB> and Ba<SUB>2</SUB>NdMoO<SUB>6</SUB> for H<SUB>2</SUB> oxidation is 1.09 and 1.19 eV. </LI> </UL> </P>

Meticulous insight on the state of fuel in a solid oxide carbon fuel cell

Jang, H.,Park, Y.,Lee, J. Elsevier 2017 CHEMICAL ENGINEERING JOURNAL -LAUSANNE- Vol.308 No.-

In a solid oxide carbon fuel cell (SO-CFC), it has been widely believed that solid-state carbonaceous materials would directly take part in electrochemical reaction to generate electrons. Of late, however, it is predicted that further-oxidizable gas-state molecules, such as CO, hydrocarbons, play a crucial role in an SO-CFC operation. In this work, we controlled an anode chamber atmosphere by providing an inert purging gas to verify the role of carbon-induced gas-state molecules; that is, some experiments were carried out with a purging gas and the others were without a purging gas. Additionally, in some of the experiments, alumina wool was placed between carbon and a cell to prevent a solid-state fuel from reaching anode surface, i.e. alumina wool is a gas diffusion layer between a solid-state fuel and anode surface. As a result, maximum power density of 230mWcm<SUP>-2</SUP> was obtained when the test was taken under no Ar without alumina wool; 80mWcm<SUP>-2</SUP> under Ar flow without alumina wool; 212mWcm<SUP>-2</SUP> under no Ar with alumina wool; potential value going zero under Ar with alumina wool. In other words, it is corroborated that gas-state molecules mainly govern power performance and hence SO-CFC operation.

가스터빈의 성능과 연료전지의 출력비중이 고체산화물 연료전지/가스터빈 하이브리드 시스템 성능에 미치는 영향

안지호(Ji-Ho Ahn),강수영(Soo Young Kang),김동섭(Tong Seop Kim) 대한기계학회 2012 大韓機械學會論文集B Vol.36 No.4

출력 규모가 다른 세가지 상용 가스터빈들을 바탕으로 고체산화물 연료전지/가스터빈 하이브리드 시스템을 구성하고 성능을 비교하였다. 각 가스터빈을 사용할 때 연료전지와 가스터빈의 출력 비중 및 효율을 비교, 분석하였고 연료전지 설계온도를 변화시키면서 출력 비중의 변화와 시스템 효율 변화를 분석하였다. 수십 ㎾ 급 소형 가스터빈을 사용한 하이브리드 시스템에서는 연료전지 온도가 변하여도 효율은 거의 변화가 없었지만 ㎿ 급 및 수백 ㎿ 급 등 중,대형 가스터빈을 사용하는 경우에는 연료전지 작동온도가 높아질수록 시스템 효율이 높아짐을 확인하였다. 또한 연료전지로 공급되는 공기량을 조절하여 연료전지 출력 비중을 변화시키는 것에 대해서도 해석하였다. Solid oxide fuel cell/gas turbine hybrid systems that use three gas turbines having different power outputs were devised and their performance was compared. The power shares of the gas turbine and fuel cell and the net system efficiency were compared among the three systems, and their variations with the design fuel cell temperature were investigated. The system efficiency was predicted to be insensitive to the fuel cell temperature in the sub-㎿ system, but it increased with increasing fuel cell temperature in both the multi-㎿ and hundred-㎿ systems. The influence of air bypass around the fuel cell on the system performance was also investigated.

Improving the Stability of Series-Connected Solid Oxide Fuel Cells by Modifying the Electrolyte Composition

Kim, Young Je,Lim, Hyung-Tae The Korean Electrochemical Society 2021 Journal of electrochemical science and technology Vol.12 No.1

YSZ based anode supported solid oxide fuel cells (SOFCs) were prepared, and two cells with different electrolyte thicknesses were connected in series for the simulation of a cell-imbalanced fuel cell stack. Pure YSZ cells in a series connection exhibited a rapid degradation when a thick electrolyte cell was operated under a negative voltage. On the other hand, ceria added-YSZ cells in a series connection were stable under similar operating conditions, and the power density and impedance were about the same as those before tests. The improved stability was due to the reduction of internal partial pressure in the electrolyte by locally increasing the electronic conduction. Thus, we propose a new protection method, i.e., the local addition of ceria in the YSZ electrolyte, to extend the lifetime of a cell-imbalanced SOFC stack.

NH4^+/H3O^+-β-Alumina 전해질을 이용한 저온형 세라믹 연료전지 기술

임성기,김우성 건국대학교 산업기술연구원 2003 건국기술연구논문지 Vol.28 No.-

The researches of alternative energy are carried out to reduce the dependence of fossil energy in these days. Hydrogen energy, one of the candidates of alternative, is drawing attention due to their environmental compatibility and recyclable ability, and it is most suitable for fuel of fuel cells. Solid oxide fuel cells (SOFC) which is called the fuel cell for next generation have many advantages such as high conversion efficiency, environmental compatibility, modularity, siting flexibility, but its high operating temperature imposes stringent material and processing requirements. For the alternative proposal for those problems, the low temperature ceramic fuel cell using NH4+/H30+ -beta-alumina for electrolyte is being investigated. In this paper, the characterization of low temperature ceramic fuel cell and electrolyte are described.

메탄연료사용을 위한 고체산화물 연료전지용 Reduced Graphene Oxide/Sr0.98Y0.08TiO3-δ 연료극 개발

김형순,김준호,모수인,박광선,윤정우 한국화학공학회 2023 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.61 No.2

Solid oxide fuel cell has received more attention recently due to the fuel flexibility via internal reforming. Commonly used Ni/YSZ anode, however, can be easily deactivated by carbon coking in hydrocarbon fuels. The carbon deposition problem can minimize by developing alternative perovskite anode. This study is focused on improving conductivity and catalytic activity of the perovskite anode by introducing rGO (reduced graphene oxide). Sr0.92Y0.08TiO3(SYT) anode with perovskite structure was synthesized with 1wt% of rGO. The presence of rGO during anode fabricating process and cell operation is confirmed through XPS and Raman analysis. The maximum power density of rGO/SYT anode improved to 3 times in H2 and 6 times in CH4 comparing to that of SYT anode due to the high electrical conductivity and good catalytic activity for CH4.

저온 고체산화물연료전지 구현을 위한 다층 나노기공성 금속기판의 제조

강상균,박용일,Kang, Sangkyun,Park, Yong-Il 한국세라믹학회 2005 한국세라믹학회지 Vol.42 No.12

Submicron thick solid electrolyte membrane is essential to the implementation of low temperature solid oxide fuel cell, and, therefore, development of new electrode structures is necessary for the submicron thick solid electrolyte deposition while providing functions as current collector and fuel transport channel. In this research, a nickel membrane with multi-stage nano hole array has been produced via modified two step replication process. The obtained membrane has practical size of 12mm diameter and $50{\mu}m$ thickness. The multi-stage nature provides 20nm pores on one side and 200nm on the other side. The 20nm side provides catalyst layer and $30\~40\%$ planar porosity was measured. The successful deposition of submicron thick yttria stabilized zirconia membrane on the substrate shows the possibility of achieving a low temperature solid oxide fuel cell.