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1

PEM electrolysis system performance and system safety integration

Chidziva Stanford, Malinowski Marek, Bladergroen Bernard, Pasupathi Sivakumar, Lototskyy Mykhaylo

Przegląd Elektrotechniczny

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2020

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R. 96, nr 12

1--8

EN

In this paper, the performance and design of hydrogen production system using two commercial 4.2 kW proton exchange membrane (PEM) water electrolysis stacks embedded in a custom-designed electrolyser is described. The PEM electrolyser system has multiple levels of construction which include, stack section, cooling unit, Balance of Plant (BOP), power electronics and system safety, all integrated with aid of PLC controller. Particular system alarms and fault conditions trigger the emergency mode, which safely shuts down the system. A crucial aspect of design and operation protocols around hydrogen safety application in the whole integration process is applied. The system integrated with in-house built metal hydride compressor supplies high pressure hydrogen (up to 200 bar, 5 Nm3/h) to SAIAMC testing facilities.

PL

Artykuł omawia konstrukcję oraz badanie osiągów systemu przeznaczonego do produkcji wodoru, który został zbudowany na bazie dwóch stosów elektrolizy wody typu PEM (4.2 kW każdy).System elektrolizera składa się z szeregu podzespołów, do których zaliczają się sekcja stosów, układ chłodzenia, zespół urządzeń wspomagających proces elektrolizy (BoP), układy zasilania elektrycznego, układ zabezpieczeń oraz kontroler typu PLC. Z uwagi na istotny aspekt bezpiecznej produkcji wodoru, kontroler wyłącza system w razie wystąpienia stanów alarmowych. System zintegrowano z kompresorem działającym w oparciu o wodorki metali, dostarczającego wodór przy wysokim ciśnieniu (200 bar, 5 Nm3/h) do laboratoriów badawczych (SAIAMC) na użytek własny.

2

Simulation of start-up behaviour of a passive autocatalytic hydrogen recombiner

Rożeń A.

Nukleonika

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2018

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Vol. 63, No. 2

27--41

EN

Heterogeneous catalytic recombination of hydrogen with oxygen is one of the methods used to remove hydrogen from the containment of a light-water nuclear reactor (LWR). Inside a passive autocatalytic recombiner (PAR), hydrogen and oxygen molecules are adsorbed at catalyst active spots and they recombine to yield water. Heat released in this exothermic reaction creates natural convection of gas in the spaces between the elements supporting a catalyst. Hot and humid gas fl ows upwards into the PAR chimney, while fresh, hydrogen-rich gas enters the PAR from below. Catalytic recombination should start spontaneously at room temperature and low hydrogen concentration. Computational fl uid dynamics (CFD) has been used to study the dynamic behaviour of a plate-type Areva FR-380 recombiner in a quiescent environment for several test scenarios, including different rates of increase in hydrogen concentration and temporary catalyst deactivation. A method for the determination of pressure boundary conditions at the PAR exits was proposed and implemented into a CFD code. In this way, transient operation of PAR could be simulated without the need to model gas circulation outside the device. It was found that fi rst a slow downward fl ow of gas is developed, which may persist until the temperature of the catalyst foils rises. As soon as the gas inside the PAR absorbs enough heat to become lighter than the gas outside the PAR, it starts to fl ow upwards. Criteria for determining the start-up time of PAR were proposed. Model predictions were also compared with experimental data obtained in tests conducted at the THAI facility.

3

Simulation of large scale hydrogen - air detonation with the aid of CFD

Machniewski P., Molga E.

Inżynieria i Aparatura Chemiczna

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2017

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Nr 3

88--89

EN

Application of Computational Fluid Dynamics (CFD) methodology for the simulation of industrial scale hydrogen detonation accident scenario is demonstrated in this work. The CFD model based on the reactive Euler equation set and one-step Arrhenius kinetics with tuned parameters at moderate computational cost in 2D geometry, allowed for satisfactory agreement of calculated overpressure field and detonation front velocity with the published measurement results taken during large scale (300 m3 hemisphere) open-space detonation of stoichiometric hydrogen - air mixture.

PL

Przedstawiono użycie metodologii obliczeniowej mechaniki płynów (CFD) do symulacji sytuacji awaryjnych związanych z wybuchem detonacyjnym mieszaniny wodom i powietrza o zasięgu typowym dla w skali przemysłowej. Podano wyniki obliczeń opartych na równaniach Eulera dla ośrodka ściśliwego z jednoetapową reakcją chemiczną, której kinetykę modelowano za pomocą równania Arrheniusa o odpowiednio dobranych parametrach. Uzyskano zadowalającą zgodność przewidywanego nadciśnienia fali uderzeniowej oraz prędkości frontu fali detonacyjnej, obliczonych podczas symulacji 2D, z opublikowanymi wynikami pomiarów przeprowadzonych podczas detonacji stechiometrycznej mieszaniny wodom i powietrza w półsferycznym balonie o pojemności 300 m3 w przestrzeni otwartej.

4

Numerical investigation on the effect of obstacles on DDT in hydrogen-air mixure using OpenFOAM

Porowski R., Siatkowski S.

Archivum Combustionis

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2017

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Vol. 37 nr 1

15--24

EN

During past decades a lot of effort was put into DDT and detonation research both experimental and numerical. However the size of a domain, in which we can simulate DDT is very limited due to computer performance. In days to come, the next challenge will be to create numerical model that would allow us to simulate huge domains such as hydrogen leaks in nuclear power plants. An attempt to create such model was taken by Ettner (2014) who created ddtFOAM solver running on OpenFOAM package dedicated to simulate deflagration-to-detonation transition without resolving all microscopic details of the flow (only 2D simulations). According to Ettner (2014) it works on relatively coarse grid (1x1mm) and shows good agreement with experiments. The purpose of this paper was to investigate the influence of obstacles on DDT and detonation in tube filled with stoichiometric hydrogen-air mixture using ddtFOAM solver for the same geometry as Porowski’s experiments (2013). This work was restricted only to hydrogen-air mixture although in the future it is planned to be extended to other mixtures that Porowski (2013) used in his experiments. Simulated geometry included the tube with length L = 6 m and D=140 mm. Twelve different configurations of obstacle were used, various parameters as BR (Blockage Ratio) ranging from 0.4 to 0.7 and obstacle spacing between 1D and 3D. Our study showed that model captured general features of detonations such as velocity or pressure peak, fairly well. However not always results of simulation was in agreement with experimental studies. Main disagreement was in predicting if DDT occurred or not. Simulations showed steady-state detonation protruding in every case while in experiments sometimes flame propagated in quasi-detonation regime. It should be noted though, that this model is supposed to give more qualitative than quantitative results. Some possible causes for this disagreement of results are then analysed.

5

Numerical and experimental investigations on self - ignition process of hydrogen gas release

Jach A., Rudy W., Dąbkowski A., Teodorczyk A.

Journal of KONES

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2013

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Vol. 20, No. 3

185--192