• Korean Chemical Engineering Research
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• 제43권3호
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• pp.352-359
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• 2005

본 논문에서는 암모니아의 전해 분해를 위한 분리막 반응기의 음극방 및 양극방에서 물의 전해에 따른 암모니아 용액의 pH 변화가 고찰되었으며, 단위 전해 셀이 적층된 다단 전해 반응기에서의 암모니아의 연속식 분해 특성이 평가되었다. 분리막을 가지는 반응기에서 암모니아 용액의 전해 반응 시, 양극에서는 pH가 8 이하에서부터 수소 이온이 생성되는 물 분해 반응이 일어나며, 음극에서는 pH가 11 이상에서부터 수산기 이온이 생성되는 물 분해 반응이 일어나 암모니아 용액의 pH를 변화시켜 암모니아 전해 분해에 영향을 크게 미쳤으며, 음이온 교환막을 사용하는 경우가 양이온 교환막을 사용하는 경우보다 양극방에서 암모니아 분해에 유리한 알카리 분위기를 보다 효과적으로 유지할 수 있었다. 분리막 전해 반응기의 특성을 이용하여 자체 pH 조정 기능을 가지는 연속식 암모니아 전해 반응기가 새롭게 고안하였고, 여기서는 pH-조정조 탱크 용액을 두고 이의 용액 일부를 음극방으로 순환시킴으로써, 양극방으로 주입되는 pH-조정조의 용액의 pH를 높여 암모니아 분해율을 높일 수 있었다. 또한, 그러한 반응기를 이용한 salt-free 연속식 암모니아 전해 분해 공정이 제시되었으며, 이러한 공정에서는 염소 이온을 가지는 암모니아 용액의 80％까지 연속적으로 암모니아를 환경에 무해한 질소로 분해 시킬 수 있었다.

• 한국수소및신에너지학회논문집
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• 제31권4호
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• pp.337-344
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• 2020

Worldwide, there is a significant surge in the efforts for addressing the issue of global warming; the use of renewable energy is one of the solutions proposed to mitigate global warming. However, severe volatility is a critical disadvantage, and thus, power-to-gas technology is considered one of best solutions for energy storage. Hydrogen is a popular candidate from the perspective of both environment and economics. Accordingly, a hydrogen production system based on renewable energy sources is developed, and the economics of the system are assessed. The result of the base case shows that the unit cost of hydrogen production would be 6,415 won/kg H₂, with a hydrogen production plant based on a 100 MW akaline electrolyzer and 25% operation rate, considering renewable energy sources with no electricity cost payment. Sensitivity study results show that the range of hydrogen unit cost efficiency can be 2,293 to 6,984 Won/kg H₂, depending on the efficiency and unit cost of the electrolyzer. In case of electrolyzer operation rate and electricity unit cost, sensitivity study results show that hydrogen unit cost is in the range 934-26,180 won/kg H₂.

• 조명전기설비학회논문지
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• 제20권4호
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• pp.12-20
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• 2006

중화학 공업은 전해조를 포함한 비선형 부하를 가지고 있다. AC-DC 컨버터로 구성된 전해조는 고조파 전류를 발생시키고, 전력 계통의 전압을 왜곡 시킨다. 본 논문에서는 전해조 부하의 고조파 현장 측정, 고조파 저감을 위해 수용가 모선에 동조 필터 적용과 국제 고조파 관리 기준인 IEC 61000-3-6과 IEEE 519에 의한 고조파 평가를 심도있게 분석한다. 고조파 해석 프로그램인 EDSA는 사례연구에 시뮬레이션 도구로 사용되었다.

• 조명전기설비학회논문지
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• 제20권2호
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• pp.29-37
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• 2006

중화학 공업은 전해조를 포함한 비선형 부하를 가지고 있다. AC-DC 컨버터가 화학공장의 전해조에 널리 쓰이고 있고, 전해조는 DC에 연결된 구조이다. 컨버터는 고조파 전류를 발생시키고, 전력계통의 전압을 왜곡시킨다. 본 논문에서는 전해조 부하의 고조파 현장 측정과 국제 고조파 관리 기준인 IEC 61000-3-6과 IEEE 519-1992에 의한 고조파 평가를 심도있게 분석한다.

• 신재생에너지
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• 제3권2호
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• pp.60-67
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• 2007

This paper describes the design and integration of the wind-fuel cell hybrid system. The hybrid system components included a wind turbine, an electrolyzer (for generation of H2), a PEMFC (Proton Exchange Membrane Fuel Cell), hydrogen storage tank and BOP (Balance of Plant) system. The energy input is entirely provided by a wind turbine. A DC-DC converter controls the power input to the electrolyzer, which produces hydrogen and oxygen form water. The hydrogen used the fuel for the PEMFC. Hydrogen may be produced and stored in high pressure tank by hydrogen gas booster system. Wind conditions are changing with time of day, season and year. So, wind power is a variable energy source. The main purpose with these WT-FC hybrid system is to store hydrogen by electrolysis of water when wind conditions are good and release the stored hydrog en to supply the fuelcell when wind is low.

• KEPCO Journal on Electric Power and Energy
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• 제7권1호
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• pp.137-143
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• 2021

As an electrochemical water electrolysis for green hydrogen production, both polymer electrolyte membrane (PEM) and alkaline electrolyte are being developed extensively in various countries. The PEM electrolyzer with high current density (above 2 A/cm²) has the advantage of being able to design a simple structure. Also, it is known that it has high response to electrical output fluctuations. However, the cost problem of major components is the most important issue that a PEM electrolyzer must overcome. Instantly, there are platinum group metal (PGM)-based electrocatalysts, fluorine-based polyfluoro sulfuric acid (PFSA) membrane, Ti felt (porous transport layer, PTL) and so on. Another challenging issue is productivity. A securing outstanding productivity brings price benefits of the electrolytic cells. From this point of view, we conducted basic studies on manufacturing electrode and membrane electrode assembly (MEA) for PEM electrolyzer production.

• 전기화학회지
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• 제20권1호
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• pp.18-25
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• 2017

본 총설에서는 최근 전세계적으로 각광 받고 있는 유기 금속 할라이드 페로브스카이트 소재에 기반한 태양광 물분해 연구에 대해 정리하였다. 크게, 현재까지 연구보고들을 태양전지-전기분해기 구성 (photovoltaic-electrolyzer configuration) 및 통합 태양광 물분해 (integrated photoelectrolysis)로 분류하여 최근 연구결과들을 소개하였다. 해당 분야 연구는 아직 초기 단계에 있으며, 향후 효과적인 보호막 개발, 고전압 텐덤전지 제작 등이 필요함을 보였다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2007년도 하계학술대회 논문집
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• pp.533-535
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• 2007

The design of tunned filters for six-pulse thyrister converter is discussed. For electrolyzer system, the design procedure of tunned filters of AC 14.4kV power system are proposed by dynamic simulation. It is shown that these harmonic filters can meet most operational requirments. By careful specification of the transformer reactance, very low harmonic content and high power factor may be achieved at a specific operating point. The the proposed design procedure is verified with the simulation results.

• Journal of Electrochemical Science and Technology
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• 제13권3호
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• pp.369-376
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• 2022

In this study, the stability of an anion exchange membrane water electrolyzer (AEMWE) cell was evaluated in an on-off cycling operation with respect to an applied electric bias, i.e., a current density of 500 mA cm^-2, and an open circuit. The ohmic and polarization resistances of the system were monitored during operation (~800 h) using electrochemical impedance spectra. Specific consideration was given to the ohmic resistance of the cell, especially that of the membrane under on-off cycling conditions, by consistently feeding the cell with KOH solution. Owing to an excess feed solution, a momentary increase in the polarization resistance was observed immediately after the open-circuit. The excess feed solution was mostly recovered by subjecting the cell to the applied electric bias. Stability tests on the AEMWE cell under on-off cycling with continuous feeding even under an open circuit can guarantee long-term stability by avoiding an irreversible increase in ohmic and polarization resistances.

• 한국수소및신에너지학회논문집
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• 제7권1호
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• pp.29-37
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• 1996

Alkaline water electrolysis has been commercialized as the only large-scale method for a long time to produce hydrogen and the technology is superior to other methods such as photochemical, thermochemical water splitting, and thermal decomposition method in view of efficiency and related technical problem. However, such conventional electrolyzer do not have high electric efficiency and productivity to apply to large scale hydrogen production for energy or chemical feedstocks. Solid polymer electrolyte water electrolysis using a perfluorocation exchange membrane as an $H^+$ ion conductor is considered to be a promising method, because of capability for operating at high current densities and low cell voltages. So, this is a good technology for the storage of electricity generated by photovoltaic power plants, wind generators and other energy conversion systems. One of the most important R&D topics in electrolyser is how to minimize cell voltage and maximize current density in order to increase the productivity of the electrolyzer. A commercialized technology is the hot press method which the film type electrocatalyst is hot-pressed to soild polymer membrane in order to eliminate the contact resistance. Various technologies, electrocatalyst formed over Nafion membrane surface by means of nonelectrolytic plating process, porous sintered metal(titanium powder) or titanium mesh coated with electrocatalyst, have been studied for preparation of membrane-electrocatalyst composites. In this study some experiments have been conducted at a solid polymer electrolyte water electrolyzer, which consisted of single cell stack with an electrode area of $25cm^2$ in a unipolar arrangement using titanium mesh coated with electrocatalyst.