국내 저온수전해 수소생산의 경제성 평가

김봉진,김종욱,고현민 한국수소및신에너지학회 2011 한국수소 및 신에너지학회논문집 Vol.22 No.4

This paper deals with an economic evaluation of domestic low-temperature water electrolysis hydrogen production. We evaluate the economic feasibility of on-site hydrogen fueling stations with the hydrogen production capacity of 30 Nm^3/hr by the alkaline and the polymer electrolyte membrane water electrolysis. The hydrogen production prices of the alkaline water electrolysis, the polymer electrolyte membrane water electrolysis, and the steam methane reforming hydrogen fueling stations with the hydrogen production capacity of 30 Nm^3/hr were estimated as 18,403 won/kgH_2, 22,945 won/kgH_2, 21,412 won/kgH_2, respectively. Domestic alkaline water electrolysis hydrogen production is evaluated as economical for small on-site hydrogen fueling stations, and we need to further study the economic evaluation of low-temperature water electrolysis hydrogen production for medium and large scale on-site hydrogen fueling stations.

VMD 생산수의 수소 생산 용수 적용성

최미연(Miyeon Choi),문덕수(Deoksoo Moon),김현주(Hyeonju Kim) 한국해양환경·에너지학회 2021 한국해양환경공학회 학술대회논문집 Vol.2021 No.10

본 연구에서는 VMD(Vaccum Membrane Distillation)의 유입수의 온도와 농도를 달리하였을 때의 생산수의 성분 변화를 살펴보고, VMD 생산수를 수소 생산을 위한 수전해에 적용할 경우 용수로써 적합한지 여부를 분석하였다. 열에 의한 상변화와 분리막 기술을 결합한 해수 담수화 기술인 막증류 기술(Membrane Distillation, MD)은 소수성 분리막을 중심으로 온도차에 의한 증기압을 구동력으로 사용하는 공정이다. 이 때 투과측에 진공압을 걸어 주어 생산수를 얻는 형태가 VMD이다. VMD는 기존의 증발법에 비해 낮은 온도로 운전가능하며, RO 공정에 비해 운전에 필요한 에너지 소모량이 적고 100%에 가까운 염제거율을 가진다. 또한 유입수의 염분 농도에 생산수의 수질이 크게 변하지 않아 고농도의 염분을 가진 농축수를 처리하기에 적합하다. 물 전기분해에 의한 수소 제조기술에는 PEM형수전해, 고온수증기전해, 알칼라인수전해 등이 있으며, VMD 생산수를 이들 기술에 적용하여 수소 생산가능성을 알아보았다. In this study, changes in the composition of the produced water when the temperature and concentration of the influent of VMD(Vacuum membrane distillation) were changed were examined, and whether VMD produced water was suitable as water when applied to water electrolysis for hydrogen production was analyzed. Membrane distillation(MD) is a seawater desalination technology that involves phase change via heat and membrane technology. The driving force behind MD is the vapor pressure generated by the temperature differences between the two sides of a hydrophobic membrane. VMD is a derivative technology used to desalinate seawater by generating vacuum pressure on the permeate side. VMD can be carried out at lower temperatures compared to evaporation methods, and it consumes less energy than RO process. Also, it is suitable for the treatment of concentrated water with a high salt concentration, because the quality of the water obtained after distillation is not significantly affected by the salinity of the feed water. Hydrogen production technology by water electrolysis includes PEM-type water electrolysis, hot water steam electrolysis, and alkaline water electrolysis, and the possibility of hydrogen production was investigated by applying VMD production water to these technologies.

Fabrication of Membrane Electrode Assemblies for PEM Electrolysis of Tritiated Water

Euna Jeong,Ilgook Kim,Kyung Jin Lee,Chan-Woo Park 한국방사성폐기물학회 2023 한국방사성폐기물학회 학술논문요약집 Vol.21 No.1

For decontamination and quantification of trace amount of tritium in water, an efficient separation technology capable of enriching tritium in water is required. Electrolysis is a key technology for tritium enichment as it has a high H/T and D/T separation factors. To separate tritium, it is important to develop a proton exchange membrane (PEM) electrolyzer having high hydrogen isotope separation factor as well as high electrolyzer cell efficiency. However, there has not been sufficient research on the separation factor and cell efficiency according to the composition and manufacturing method of the membrane electrode assembly (MEA) Therefore, it is necessary to study the optimal composition and manufacturing method of the MEA in PEM electrolyzer. In this study, the H/D separation factor and water electrolysis cell efficiency of PEM electrolyzer were analyzed by changing the anode and cathode materials and electrode deposition method of the MEA. After the water electrolysis experiment using deionized water, the D/H ratio in water and hydrogen gas was measured using a cavity ring down spectrometer and a mass spectrometer, respectively, and the separation factor was calculated. To calculate the cell efficiency of water electrolysis, a polarization curves were obtained by measuring the voltage changes while increasing the current density. As a result of the study, the water electrolyzer cell efficiency of the MEA fabricated with different anode/cathode configurations and electrode formation methods was higher than that of commercial MEA. On the other hand, the difference in H/D separation factor was not significant depending on the MEA fabrication methods. Therefore, using a cell with high cell efficiency when the separation factor is the same will help construct a more efficient water electrolysis system by lowering the voltage required for water electrolysis.

차아염소산염과 수소생산이 동시에 가능한 PEM수전해 셀의 최적화 운전

이동현,최미진,박미정,박종관 대한환경공학회 2023 대한환경공학회지 Vol.45 No.9

목적 : 본 연구는 MEA가 설치된 격막식 PEM 수전해 셀을 사용하여 수소와 차아염소산염을 동시에 생산하는 가능성을 평가하고, 최적 운전 조건을 알아보고자 한다. 방법 : 외부 전력을 Potentiostat를 통해 수전해 장치에 인가하고 수전해 반응을 유도하여 수소와 차아염소산염이 생성을 확인하였다. Linear Sweep Voltammetry(LSV) 실험으로, 수전해에 필요한 최소 전압을 확인하기 위해 전압 스캔 범위를 조절하며 전압 변화에 따른 수소 생산량을 관찰하고, 수전해에 필요한 최소 전압과 효율을 계산하였다.또한 정전류 실험으로 1A의 정전류를 인가하여 수소 생산의 안정성과 효율을 평가하였다. 수소 생산량은 질량유량계를 이용하여 측정하였으며, free chlorine 농도를 측정함으로써 차아염소산염 생성량을 확인하였다. 결과 및 토의 : PEM 수전해 셀에서 수소를 생성하기 위해 필요한 최소 전압을 확인하기 위해 DI water를 사용하여LSV실험을 수행하였다. 그 결과 약 1.4 V에서부터 전류가 증가하는 것을 확인할 수 있었고, 이때의 전압 효율은약 82% 정도 되었다. 차아염소산염 생산을 위해 anode에 NaCl을 주입하여 전기화학 반응 실험을 진행하였다. 전해질에 NaCl 용해되어 있을 때, 동일한 전류에서 전압이 DI water를 사용한 경우보다 0.77 V 증가하였다. 또한 전해질 농도와 유량에 따른 전극 접촉시간이 차아염소산염과 수소 생산에 미치는 영향을 조사하기 위해 최적화 실험을 수행하였다. 전해질 농도가 증가함에 따라 차아염소산염의 생성량이 증가하는 경향을 확인하였으며, NaCl 10 g/L일 때 Free chlorine 104±0.50 mg/L 발생하였다. 유량이 감소하는 경우 차아염소산염의 발생량이 증가하는 경향을 보였으며, 이는 전극 접촉시간이 증가함에 따라 차아염소산염 생산량이 증가하는 것으로 판단되었다. 하지만 수소 발생량은 NaCl농도와 유량에 따른 변화가 없었다. 결론 : 본 연구는 PEM 수전해 기술을 활용하여 수소 생산과 차아염소산염 생산을 동시에 이루어내는 새로운 방안을 모색하였다. MEA가 설치된 격막식 PEM 수전해 셀을 사용하여 동시에 차아염소산염과 수소를 생산하였고, Anolyte로 NaCl 전해질의 농도와 유량을 변화시킨 조건에서 생산 효율을 비교하였다. 제안된 PEM 수전해 기술은환경공학에서 이슈가 되고 있는 에너지 문제 및 오염물질 정화를 위한 대안적 기술로 제안될 수 있다고 판단된다. Objectives : This study aims to assess the feasibility of simultaneously producing hydrogen and hypochlorous acid using a 2-compartment PEM water electrolysis cell with an installed membrane electrode assembly (MEA). Methods : External power was applied to the PEM water electrolysis device through a potentiostat to induce the electrolysis reaction and to confirm the production of hydrogen and hypochlorite simultaneously. Linear Sweep Voltammetry (LSV) experiments were conducted, thereby determined the minimum voltage required for the electrolysis. Constant current experiments were performed by applying a fixed current of 1 A for 1 hour, measuring voltage changes every second to evaluate the stability and efficiency of hydrogen production. The hydrogen production rate was measured using a mass flow meter, while the hypochlorite production was determined using a portable free chlorine photometer. Results and Discussion : In this study, the minimum voltage required for hydrogen generation in a PEM water electrolysis cell was investigated using LSV with Deionized (DI) water. The results showed that the current increased from around 1.4 V, indicating an approximate voltage efficiency of 82%. NaCl was introduced to the anode in the PEM electrolysis cell to induce electrochemical reactions. When the anolyte was NaCl, the voltage was observed to increase by 0.77 V compared to using DI water. Optimization experiments were conducted to investigate the influence of electrolyte concentration and flow rate on hypochlorite and hydrogen production. As the electrolyte concentration increased, the hypochlorite generation also increased, with a maximum of 104±0.50 mg/L observed with NaCl 10 g/L. Additionally, when the flow rate was reduced, the hypochlorite production increased, and at a reduced flow rate of 5 mL/min compared to 20 mL/min, hypochlorite generation increased by 127.3%. However, the hydrogen production showed no significant variation with NaCl concentration or flow rate. Conclusion : This study explores a novel approach using PEM water electrolysis technology to simultaneously produce hydrogen and chlorinated disinfectants. The research employed a PEM electrolysis cell with the MEA to generate both chlorine-based compounds and hydrogen. By varying the concentration and flow rate of the anolyte, the production efficiencies of hypochlorite were compared. This system showed that PEM electrolysis can be a promising alternative for disinfection and energy production in terms of environmental protection and cost-effectiveness.

Hexagonal Boron Nitride Nanosheets for Enhanced of Tritium Separation in Water Electrolysis

Chan Woo Park,Youngho Shin,In-Ho Yoon 한국방사성폐기물학회 2022 한국방사성폐기물학회 학술논문요약집 Vol.20 No.1

Water electrolysis is a representative technology for tritium enrichment in water. Proton exchange membrane (PEM) water electrolysis has received great attention to replace traditional alkaline water electrolysis which generates concentrated tritiated water containing a large amount of salts. Nafion has been widely used as a polymeric electrolyte for the PEM electrolyzer. However, its low gas barrier property causes explosion, corrosion or degradation of electrolyzer. Furthermore, the traditional polymeric electrolytes have negligible differences in conductivity between hydrogen isotopes. To enhance the tritium separation by water electrolysis, we designed a composite membrane (Nafion/ hexagonal boron nitride (hBN)). The monolayer hBN has a high proton conductivity and gas barrier property, and the hBN can enhance conductivity differences between hydrogen isotopes. We prepared Nafion/hBN composite membranes, and water electrolysis performances and proton/deuterium separation behaviors were investigated.

수전해용 이오노머 분자동역학 모델 개발

강호성,박치훈,이창현 한국막학회 2020 멤브레인 Vol.30 No.6

본 연구에서는 수전해용 ionomer의 분자동역학 전산모사 모델 제작을 위하여, 과량의 물 분자가 존재하는 수전해 시스템의 특성을 반영한 ionomer 모델을 제작한 후, 기존 연료전지용 전해질막 전산모사 조건에 맞춰 제작한 ionomer 모델과 비교하였다. 최종적으로 얻어진 모델은 과불소계 ionomer의 중요 특징 중 하나인 명확한 상분리 및 수화채널이 관찰되었으며, 과량의 물 및 높은 운전 온도 조건에서도 물에 녹지 않고 안정된 구조를 나타내었다. 제조된 ionomer 모델에서는 과량의 물 분자로 인한 이온 희석 효과로 이온 전달 성능 감소가 나타났으며, 반대로 수소 기체의 투과는 더 증가할 것으로 분석되었다. 따라서 이러한 수전해 시스템의 특성을 반영한 수전해용 ionomer 분자 구조 설계 전략이 필요하고, 분자동역학 전산모사 연 구 시에도 이를 감안한 수전해용 ionomer 모델 제작이 필요하다. In this study, in order to build a molecular dynamics simulation model of ionomer for water electrolysis, an ionomer model that reflects the characteristics of a water electrolysis system in which excess water molecules exist was compared to an ionomer built according to the conventional simulation method of the fuel cells membrane. The final ionomer MD models have a strong phase separation and water channel that is one of the important characteristics of the perfluorinated ionomer, and are stable and water-insoluble under excessive water and high temperature conditions. In the ionomer MD models built in this study, the excess water molecules decrease an ion conductivity due to the dilution of ions, but increase a hydrogen diffusivity. Therefore, it is necessary to design the molecular structure of ionomers for water electrolysis in experimental studies as well as molecular dynamics studies according to the characteristics of the water electrolysis system reported in this study.

수전해 반응에 의한 고분자전해질 연료전지 전극과 막의 열화

정재현 ( Jae Hyeun Jeong ),신은경 ( Eun Kyung Shin ),정재진 ( Jae Jin Jeong ),나일채 ( Il Chai Na ),추천호 ( Cheun Ho Chu ),박권필 ( Kwon Pil Park ) 한국화학공학회 2014 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.52 No.6

고분자전해질 연료전지로 물을 전기분해하여 수소와 산소를 발생시킬 수 있다. 그러나 1.7V 이상의 높은 전압에서 수전해 반응이 일어나므로 전극과 고분자 전해질 막의 열화가 빠르게 진행된다. 수전해 과정에서 anode의 열화를 방지하기 위해 촉매로 지지체 없는 IrO2를 보통 사용하는데 본 연구에서는 고분자전해질 연료전지용 Pt/C 촉매를 수전해 반응에 그대로 사용했을 때 전극과 막의 열화 현상을 분석하였다. 1.8~2.0 V 전압 범위에서 수전해 반응 후 고분자전해질 연료전지 구동 조건에서 I-V, CV, 임피던스, LSV를 측정했다. 수전해 전압이 높을수록 전극과 막의 열화 속도가 증가하였다. 2.0 V에서 1분 동안 수전해 반응했을 때 수소 수율은 88%였고, 전극과 고분자 막이 열화되어 0.6 V에서 성능이 49% 감소하였다. Proton Exchange Membrane Fuel Cells (PEMFC) can generate hydrogen and oxygen from water by electrolysis. But the electrode and polymer electrolyte membrane degrade rapidly during PEM water electrolysis because of high operation voltage over 1.7V. In order to reduce the rate of anode electrode degradation, unsupported IrO2 catalyst was used generally. In this study, Pt/C catalyst for PEMFC was used as a water electrolysis catalyst, and then the degradation of catalyst and membrane were analysed. After water electrolysis reaction in the voltage range from 1.8V to 2.0V, I-V curves, impedance spectra, cyclic voltammograms and linear sweep voltammetry (LSV) were measured at PEMFC operation condition. The degradation rate of electrode and membrane increased as the voltage of water electrolysis increased. The hydrogen yield was 88 % during water electrolysis for 1 min at 2.0V, the performance at 0.6V decreased to 49% due to degradation of membrane and electrode assembly.

액상 매질의 전기전도도 변화에 의한 전해이온수 발생 특성

신동화(Dong-Hwa Shin),주재현(Jae-Hyun Ju) 한국산업융합학회 2017 한국산업융합학회 논문집 Vol.20 No.4

The following thesis researched into the characteristics of electrolytic ion water with different levels of electrical conductivity by adding NaCl into tap water which is for experimental use in multi-layered electrolytic ion water generator. Electrolytic ion water is generated by underwater electrolysis and the electrolysis generator has a simple structure, is easy to control and is highly utilized in industries. Electrolytic ion water is useful in many areas since it has a superior sterilizing power, has no possibility of secondary pollution itself as water and removes active oxygen. In the experiment, we used tap water with NaCl excluded and water with three different levels of electrical conductivity by changing NaCl concentration levels into three levels. The features of current and voltage in electrolytic ion water represented a form of quadric instead of the linear characteristic following ohm’s law. As well, as the electric conductivity of water and applied voltage increased, we were able to generate much stronger acid water and alkali water.

Consideration on the Maximum Allowable Dosage of Active Substances Produced by Ballast Water Management System Using Electrolysis

Eun-Chan KIM,Jeong-Hwan OH,Seung-Guk LEE 국제이네비해양경제학회 2016 International Journal of e-Navigation and Maritime Vol.4 No.1

The International Convention for the Control and Management of Ships’ Ballast Water and Sediments was adopted by IMO (International Maritime Organization) on 13 February 2004. Fifty-seven ballast water management systems were granted basic approval of active substance by IMO, among which thirty-seven systems were granted final approval. This paper studies the maximum allowable dosage of active substances produced by ballast water management system using electrolysis which is an approved management system by IMO. The allowable dosage of active substances by electrolysis system is proposed by TRO (Total Residual Oxidant). Maximum allowable dosage of TRO is a very important factor in the ballast water management system when using the electrolysis methods, because ballast water management system is controlled with the TRO value, and the IMO approvals are given on the basis of the maximum allowable dosage of TRO for the treatment and discharge of ballast water. However, between various management systems approved TRO concentration of maximum allowable dosage showed large differences, ranging from 1 to 15 ppm, depending on the management systems. The discrepancies of maximum allowable dosage among the management systems may depend on whether a filter is used or not, the difference in the specifications of the electrolysis module, the kind of the tested organisms, the number of individual organisms, and the difference in the water quality, etc. Ship owners are responsible for satisfying the performance standard of the IMO convention in the ports of each country therefore need to carefully review whether the ballast water management system can satisfy the performance standard of the IMO convention or not.

Effect of temperature and flow rate on performance and durability in AEM water electrolysis system

신상훈,홍영택,이장용 한국공업화학회 2020 한국공업화학회 연구논문 초록집 Vol.2020 No.-

Hydrogen is considered a promising energy source owing to its high energy density and CO2-free emission. It can be produced renewably using various methods such as steam reforming, photoproduction, and water electrolysis. Among these methods, water electrolysis has attracted much attention because it affords high efficiency and the generation of high-purity hydrogen Anion-exchange-membrane water electrolysis (AEMWE), that is, water electrolysis using an anion-exchange membrane (AEM), has been developed as an alternative in recent years. AEMWE is performed in alkaline media using non-platinum group metal (PGM) catalysts. In this study, the effects of temperature and water flow rate on the performance and durability in the AEM water electrolysis system were investigated.