Game changer in high temperature steam electrolysers with novel tubular cells and stacks geometry for pressurized hydrogen production

Project Information

GAMER

Grant agreement ID: 779486

DOI

10.3030/779486

Project closed

EC signature date 12 December 2017

Start date 1 January 2018

End date 30 September 2022

Funded under

• SOCIETAL CHALLENGES - Secure, clean and efficient energy

Total cost

€ 2 998 951,25

EU contribution

€ 2 998 951,25

Coordinated by

SINTEF AS
Norway

Periodic Reporting for period 4 - GAMER (Game changer in high temperature steam electrolysers with novel tubular cells and stacks geometry for pressurized hydrogen production)

Reporting period: 2022-01-01 to 2022-09-30

Summary of the context and overall objectives of the project

The GAMER project aims at developing a novel cost-effective tubular Proton Ceramic Electrolyser (PCE) stack technology integrated in a steam electrolyser system to produce pure dry pressurized hydrogen. The electrolyser system will be thermally coupled to renewable or waste heat sources in industrial plants to achieve higher AC electric efficiency and efficient heat valorisation by the integrated processes. The project aims at establishing a high-volume production of novel tubular proton conducting ceramic cells. The cells will be qualified for pressurized steam electrolysis operation at intermediate temperature (500-700°C). They will be bundled in innovative single engineering units (SEU) encased in tubular steel shells, a modular technology, amenable to various industrial scales. GAMER focuses on designing both system and balance of plant components with the support of advanced modelling and simulation work, flowsheets of integrated processes, combined with robust engineering routes for demonstrating efficient thermal and electrical integration in a 10kW electrolyser system delivering pure hydrogen at minimum 30 bars outlet pressure.
The consortium covers the full value chain of the hydrogen economy, from cell and SEU manufacturer (CMS), system integrators (MC2, CRI), through researchers (SINTEF, UiO, CSIC), to end users in refineries, oil and gas, chemical industry (CRI, SGSI, with advisory board members YARA and AirLiquide). All along the project, these experienced partners will pay particular attention to risk management (technical, economic, logistic, business) and ensure progress of the technology from TRL3 to TRL5. The overall consortium will perform strategic communication with relevant stakeholders in order to ensure strong exploitation of the project’s results.
GAMER focused on the demonstration of an innovative, low cost and modular hydrogen production technology utilising tubular proton conducting ceramic cells and their inherent advantages for steam electrolysis:
Scalability and modularity of the electrolyser system: the electrolyser is designed for scale (small, medium, large);
Lower operating temperature (600°C) than SOE reducing degradation associated to cation diffusion, and enabling use of lower cost steel for pressure vessel;
Production of pure dry hydrogen at the anode side, preventing risk of oxidation encountered in SOE;
Increased safety: In PCE, any increase in pH2O increases the pH2. In contrast, the SOE must have a high pO2 alone at one electrode to balance the pH2O+pH2 at the opposite electrode. Pure hot high pressure O2 is risky;
Increased robustness of tubular cells, in particular, when exposed to pressure differentials compared to planar cells;
Reduced sealing area compared to planar cells.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

The tubular cells in GAMER integrate a proton conducting electrolyte based on Y-doped Ba(Zr,Ce)O3 (BZCY). The cells consist of a porous Ni-BZCY cermet cathode for the H2 side (also ensuring mechanical strength), a thin dense BZCY-based electrolyte, a porous anode for the H2O+O2 side, and a current collector system. They are assembled in a steel pressure vessel enabling safe pressurized operation of at least 30 bars and 700 °C in high steam content. The Single Engineering Units SEU production is carried out at laboratory scale by CMS. Dedicated protocols for pre-qualification of KET components, cells and assemblies of SEUs have been established and are operated on these components to monitor yield of production and ensure safety of operation. Electrochemical testing of tubular cells using composite BGLC/BZCY steam electrodes and SEUs has been conducted showing a good transfer of manufacturing from cells to SEUs configuration. By the end of the projects, 17 SEUs have been supplied for testing in high pressure operation (up to 10 bar), with 12 of these enabling to collect reliable data sets. The typical active electrode surface area per SEU is ranging between 55-60 cm2. Electrochemical Impedance Spectroscopy (EIS) characteristics of the SEUs measured in slight electrolytic bias (10 mAcm-2) and a pressure of 10 bar are reported in Figure 1, showing both area-specific resistance and absolute resistance. As can be seen, the primary variation between the SEUs is the ohmic offset, which is significantly affected by both current collection and contact resistances within the SEU assembly. These resistances have been shown to consistently improve upon iteration and optimization of the SEU production process. In particular, it is clear that there is a significant improvement in the ohmic resistance of the SEUs made in volume production for deployment into the final electrolyser demonstrator (SEU#95). Furthermore, it is shown that both the ohmic and electrode polarization resistance decreases upon an increase in total pressure from 3 to 10 bar – accompanied by an increased faradaic efficiency (figure 2). This is a combination of kinetic and thermodynamic factors that benefit high pressure operation in PCECs.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

The proton ceramics offer several potential advantages for steam electrolysis. The direct production of dry hydrogen is a first advantage. Furthermore, the production of undiluted dry hydrogen (i) removes the risk of oxidation of Ni commonly used in H2-side electrodes (cathodes) of high temperature electrolysers and (ii) enables the direct use of the hot pressurized H2 produced, which helps in reaching high system and overall-plant energy efficiency. Additionally, the proton moves with a smaller activation energy than oxide ions enabling operation in an intermediate temperature range (400 – 700ºC), beneficial for efficient thermal coupling with renewable or waste heat. The PCE has also the benefit of a high pressure of hydrogen balanced with the sum of steam and oxygen, while the SOE must use a high pressure of solely oxygen to balance steam and hydrogen, making it more challenging to reach the same produced hydrogen pressure. In GAMER, we are currently focusing on demonstrating how these advantages can be leveraged in an innovative tubular SEU design. Innovation is brought in the project with the development of optimized H2O+O2 electrode and current collection system enabling designing a new SEU. Testing of the tubular cells in pressurized electrolysis mode have demonstrated performance and stability of operation beyond state-of-the-art for tubular proton ceramic based cells. One SEU was operated for over 500 hours at 10 bar, showing excellent stability and even a slight reduction in the cell potential while operated at a constant current density of 0.3 Acm-2 (figure 3).
The project has developed an innovative stack design to integrate the SEU in a hot-box. Each rack is dimensioned to connect 16 SEUs (fig. 6) enabling high compactness of SEUs assembly and monitoring of each rack. The testing rig has necessary BoP and hot-box built by MC2 - fig. 4,5. Two racks built by MC2 were tested at atmospheric pressure, 3 barg and 7 barg, obtaining a maximum H2 production of 0.46 NL/min at 600 °C, At atmospheric pressure, a H2 production of 0.47 NL/min and a Faradaic efficiency of 61% were reached by applying a current of 100 A. A stability test of 100 hours was performed and a decrease of the H2 production was observed although the i-v curves before and after testing are similar - fig 7. Further continuation of these efforts and exploitation of these results will be undertaken in the next European Project granted in Jan. 2023.

Pictures of the plant with integrated hot box in Spain

Work progress in GAMER: Plant overview of electrolyser system and pictures of the plant.

EIS (left) and IV-characteristics of SEU#11 tested at 3, 5 and 10 bar total pressure.

Continuous stability assessment of SEU100 at 10 bar.

i-V curves before (fresh) and after the 100 h stability test, at 600 ºC and atmospheric pressure.

IV-characteristics and faradaic efficiency of selected SEUs measured at a total pressure of 10 bar

Pictures of the SEUs and one rack