High-temperature Hydrogen Production Research Articles

A proposal for advanced supplementary technologies and a hybrid system with gas-cooled fast reactor concept ALLEGRO

A coupling of advanced reactors with high-capacity energy storage and other innovative non–nuclear energy technologies is a way to increase the flexibility and utilisation factor of the future nuclear systems and to diversify its energy outputs. In this paper, the basic layout of a hybrid system for a gas-cooled fast reactor is proposed. The system is composed of a high-temperature thermal energy storage unit coupled with a supercritical CO2 conversion cycle and both low-temperature and high-temperature hydrogen production and utilization. As a reference GFR reactor, the ALLEGRO concept is considered. The paper describes state-of-the-art and overviews potentially applicable technologies. Selection and justification of concepts of the individual parts of the hybrid system including operational conditions is also given. The R&D needs necessary for the potential implementation of the system are identified and the activities ongoing in the Czech Republic and especially in Centrum Výzkumu Řež are also described.

High-temperature green hydrogen production: A innovative– application of SOEC coupled with AEC through sCO2 HP

This study evaluates a potential coupling between AEC and SOEC through a CO2 heat pump unit that works in super-critical conditions. In such a way, thermal power requested by SOEC can be provided by recovering heat loss from AEC via the CO2heat pump. The coupled configuration is characterized by renewable electric input. Hence, the power is provided for electrolysis without more external thermal resources. The energy, economic and environmental impacts of such intervention have been determined and compared with SOEC in solo mode. The layout is created and simulated in a MATLAB SIMULINK environment.The simulation results show a potential improvement in the total energy efficiency of the whole system without an external heat resource, up to 68%, which is higher than 65% of SOEC itself, thanks to the heat recovery section that is correlated with sCO2 HP contribution. LCOH varies widely depending on SOEC size from around 2.59 €/kgH2 up to 9.27€/kgH2.

Neutronic performance of VVER-1200 reactor with advanced fuel and cladding materials

Nuclear reactor operation and safety are connected with a nuclear fuel design and its material and geometry properties. An increase in nuclear safety is therefore based on a neutronic and thermal analysis of the materials used in a core. This paper analyzes neutronic properties of a VVER-1200 fuel assembly with alternate fuel and cladding materials that consider Accident Tolerant or Advanced Technology Fuels (ATF). The ATF nuclear fuel development started with the post-Fukushima efforts and its main purpose is a reduction of the high-temperature hydrogen production from the zirconium water reaction. Five ATF cladding candidates with reference Zr-based alloy are studied in this paper as well as six ATF fuel candidates together with an additional standard UO2 reference case. The results are analysed based on the multiplication characteristics, reactivity feedbacks, and spent nuclear fuel composition.

Analysis of the Brayton cycle coupled with a small fluoride salt-cooled high-temperature reactor

Considering the environmental conditions and transportation conditions of remote areas, an inherently safe integrated energy conversion system featuring miniaturization, modularization, and high environmental adaptability is needed. The small fluoride salt-cooled high-temperature reactor (FHR) coupled with the Brayton cycle is a promising design. In this paper, the efficiency, exergy efficiency, and exergy loss of four different configurations of the supercritical carbon dioxide (S-CO2) Brayton cycle coupled with a new small fluoride salt-cooled high-temperature reactor are compared. The S-CO2 recompressor Brayton cycle has the best overall performance. Meanwhile, the effects of the cooling conditions on the thermal efficiency and exergy efficiency of different cycle configurations are discussed. When the core outlet temperature is 700°C, the efficiency of the designed S-CO2 recompressor Brayton cycle is approximately 42–44% when the cycle minimum temperature is 20–40°C. In conclusion, the designed small FHR coupled with the Brayton cycle system offers interesting performances in power generation, mineral mining, industrial steam supply, molten salt energy storage, and high-temperature hydrogen production in remote areas.

Exploiting the operational flexibility of a concentrated solar power plant with hydrogen production

The efficient integration of renewable energy with hydrogen storage is an important means for China to achieve carbon neutrality. Concentrated solar power (CSP) is an emerging technology for solar energy utilization that combines the advantages of power generation and energy storage. However, CSP has not been fully exploited because of the high generation cost and an incomplete market mechanism in China. The heat collected by CSP can be utilized for high-temperature electrolytic hydrogen production (HEHP), which is an efficient technology for hydrogen production and storage, and reducing carbon emission. Thus, a low-carbon operating mode for an integrated energy system (IES) consisting of wind, solar and hydrogen energy is proposed in this paper. First, an optimal operation model of electricity-heat-hydrogen coupling for an IES containing CSP and HEHP is established. Second, the effect of CSP with HEHP on the total operation performance of the system is evaluated from the aspects of the system economy, renewable energy utilization, and carbon emission. Finally, the model is validated by a case study of an island IES, and an optimal sizing for hydrogen energy storage and thermal energy storage of CSP is determined. The results show that CSP with HEHP can effectively improve the utilization rate of solar energy and reduce the carbon emissions of the system, offering an approach for carbon reduction planning and the operation of CSP in electric-hydrogen energy systems.

Assessment of a thin-electrolyte solid oxide cell for hydrogen production

Solid oxide electrolysis is recognized as an important pathway to efficient and sustainable hydrogen production from water. However, high operating temperature is a major limitation for this technology that increases the degradation rate, particularly at high steam to hydrogen intake concentrations. The degradation in cell performance is caused by thermal stresses and result in higher overvoltage. In this paper, a novel thin-electrolyte solid oxide cell (SOC) is tested for intermediate (750 °C) versus high (850 °C) temperature hydrogen production. The experimental testing and performance analysis of a thin-electrolyte-supported SOC operating at high steam to hydrogen ratio is reported. The cell is based on YSZ-electrolyte with a thickness of about 150 μm and gadolinia-doped ceria (GDC) bi-layers. The study focuses on the impact of high steam to hydrogen ratios of up to 95% H2O to 5% H2 and compares it with that occurs at lower ratios. In this regard, performance indicators, such as the open circuit voltage (OCV) and the current density–voltage (J–V) curves are measured and compared with the theoretical values and relevant literature. Furthermore, the electrochemical impedance spectroscopy (EIS) is performed for the cell and the impact of high steam to hydrogen ratios operation on the cells' integrity and microstructure is also examined through the scanning electron microscope (SEM) and the energy-dispersive X-ray spectroscopy (EDS) techniques.

A novel hybrid process for production of cyclohexanone oxime and high temperature hydrogen production using solar energy

In the presented study, an integrated novel process for cyclohexanone oxime and power production by utilizing solar dish collectors and high temperature hydrogen production systems (water decay) is studied. This process is comprised from solar dish collectors, Cu-Cl thermochemical cycle, direct H2O2 production cycle, cyclohexanone oxime and organic Rankine cycle. In the thermochemical process, 2208 kg/h of oxygen and 278.5 kg/h of hydrogen are generated that 139.4 kg/h of hydrogen is the net generated hydrogen. Moreover, this system generates 9429.8 kW of power that 2419 kW of power is employed in Cu-Cl cycle, 808.8 kW is consumed in hydrogen peroxide production cycle and the rest, which is 6202 kW is the net produced power. This process for 6305.9 kg/h cyclohexanone produces 8504.3 kg/h cyclohexanone oxime. The cyclohexanone ammoximation also generates 1238 kW heat. Furthermore, a sensitivity analysis is performed to investigate the effect of some performance parameters on various design indicators. It can be comprehended that the increment of operating wall temperature leads to decrement of solar collector energy efficiency. On the other hand, increment of geometric concentration ratio results in higher collector thermal efficiency. By using more solar dishes, the generated cyclohexanone oxime, hydrogen and hydrogen peroxide molar flow rates rises 40.5%. 43.5% and 37.8%, respectively. Moreover, the organic Rankine cycle and total system’s efficiency increases 38.1% and 43.3%, respectively by increase in number of solar dishes.

High-Pressure Operation of Proton-Conducting Electrolyzers for High-Temperature Water Splitting

In this work, we present our progress on high-temperature water splitting (HTWS) and hydrogen production at elevated pressure using proton-conducting ceramics. The electrochemical performance of the proton-conducting electrolyzer unit-cell stack is analyzed at 550 °C and pressures up to 12 bar.Proton-conducting ceramics are a promising new class of electrochemical cells due to their high proton conductivity at intermediate temperatures in comparison to more-conventional solid-oxide or molten-carbonate counterparts. Materials exploration continues for fabricating proton conducting cells to achieve better electrochemical performance during operation. Recently, lower ohmic resistance and degradation rates have been observed using the highly proton-conductive and chemically stable perovskite BaCe0.4 Zr0.4 Y0.1 Yb0.1 O3−δ (BCZYYb4411). In this study we work with a composite of Ni–BZCYYb4411 as the fuel electrode (cathode), BCZYYb4411 as the electrolyte and BCFZY as the steam electrode (anode). The cathode and electrolyte layers of the membrane-electrode assemblies used in this study are synthetized using the solid-state reactive sintering (SSRS) method. SSRS is an attractive MEA-fabrication method, as it greatly reduces the number of costly and time-consuming high-temperature sintering processes. During SSRS, single-phase protonic-ceramic perovskite is formed from parent oxides during high-temperature co-sintering of the anode-electrolyte layers. This is in contrast to more-traditional processing, in which the desired phase is first formed in powder form through calcination of parent oxides, while MEA formation is executed in follow-on high-temperature sintering steps.The cathode support is formed by dry-pressing to produce a 57-mm-dia x 1.5-mm-thick disc. The electrolyte (~ 10 mm) layer is deposited using an ultrasonic spray atomizer. The process control and narrow particle size distribution delivered by the ultrasonic atomizer consistently produces a high-density electrolyte, while minimizing thickness. We are now extending the use of ultrasonic spray deposition to other critical components such as the air-steam electrode and interfacial layers.As shown in Figure 1a, the protonic-ceramic membrane-electrode assembly (MEA) is bonded to a composite ceramic frame and assembled into a sealed cell stack with metallic interconnects, current collectors, sealing gaskets and end plates. The stack is placed in a preloaded spring-based mechanical compression system that axially compresses the electrolyzer stack while avoiding any direct compression of the MEA. The assembly is placed in a sealed vessel (Figure 1b); anode and cathode gas pressures are balanced across the MEA, and with the surrounding inert vessel gas (N2). Downstream back-pressure regulators maintain electrolyzer and vessel pressures to minimize the risk of cell fracture.Despite the challenges associated with high pressure operation, this technology is key to address some of the main issues associated with proton conducting ceramics. Higher pressure operation should lead to higher efficiencies by decreasing the electron hole concentration in the electrolyte usually associated with the electron leakage problem. Also, electrode activity can be enhanced at higher pressures, enabling higher currents at lower driving voltages. Figure 1c shows an increased electrolyzer performance of almost 50% when the operating pressure is raised to 12.5 bar. This is evidence of the better kinetics and lower power required to electrolyze at higher pressures.In parallel, the high-pressure protonic-ceramic electrolyzer delivers a pure, dry, pressurized hydrogen product stream that does not require downstream separation processes. Pressurized operation reduces downstream compression needs. Elevated-pressure operation is also beneficial for the synthesis of electrofuels, where green hydrogen is transformed into higher-value chemical. These chemistries often require high temperatures and pressures to achieve meaningful production rates. Ammonia serves as an example, the second-most-produced global chemical that contributes nearly 1.5% of global annual CO2 emissions. We are currently integrating our high-pressure electrolysis operation with ruthenium-based catalysts for electrochemical ammonia synthesis. In this talk, our progress in electrochemical energy storage with proton-conducting ceramics will be reviewed. Figure 1

High Pressure Operation of Reversible Protonic Ceramic Electrochemical Cells

We present our development of proton-conducting ceramics for high-temperature water splitting (HTWS) and hydrogen production at elevated pressure. One of the challenges of intermittent renewable energy production from solar and wind is the mismatch between generation and demand. This decoupled production and consumption of energy has motivated extensive research in electrochemical energy storage. Depending on the application and timescale, a variety of reversible electrochemical cells are needed to address the energy storage needs of intermittent renewable energy sources. For long-term energy storage and electrical-to-chemical energy conversion, high-temperature solid-oxide electrolyzers are attractive. In this work we present some of the advantages and recent developments of electrolyzers based on protonic-ceramic materials. Protonic-ceramic electrolyzers (PCECs) have shown an encouraging performance trajectory in recent years. PCECs can deliver a pure-H2 product stream, simplifying downstream separations. Higher-pressure PCEC operation (~ 10 bar) has been demonstrated, but is at an early stage. In this presentation, we highlight a unique installation that permits the study of these systems in a variety of configurations under high-pressure conditions.Reversible protonic ceramic electrochemical cells (RePCEC) are attracting attention due to their potential low cost, energy flexibility and high proton conductivity at intermediate temperatures (300 – 700 ºC). Previous studies focus either on protonic ceramic fuel cells (PCFCs) for power generation or protonic ceramic electrolysis cells (PCECs) for dry hydrogen production. Electronic leakage through the protonic-ceramic electrolyte presents a concern; high Faradaic efficiency has been demonstrated, but has also seen wide variance across studies. Low electrode activity can also reduce Faradaic efficiency, especially at higher current densities and driving voltages. Additionally, although Hydrogen is well known for its excellent characteristics as a fuel, its low density represents a challenge since it must be compressed to high pressures for storage and transportation.In this context, high-pressure operation of RePCECs is presented as key technology to address the challenges described. Higher total pressure operation should lead to higher efficiencies by decreasing the electron hole concentration in the electrolyte, thereby diminishing the electron leakage problem. High pressure can also boost electrode activity, enabling higher currents at lower driving voltages. From a cost perspective, high-pressure electrolysis reduces downstream compression needs. Operating at pressure is potentially even more important for electrofuels, where green hydrogen is transformed into higher-value chemicals; these chemistries often require high temperatures and pressures to achieve meaningful production rates. Ammonia serves as an example; the second-most-produced global chemical that contributes nearly 1.5% of global annual CO2 emissions.In this work, we present our progress on high-pressure operation of RePCECs. The electrochemical performance of protonic-ceramic electrolyzer stacks is characterized at 550 ºC and pressures up to 12 bar. The figure shows assembly of a unit-cell stack; the protonic-ceramic membrane-electrode assembly (MEA) is bonded to a composite ceramic frame and assembled into a sealed cell stack with metallic interconnects, current collectors, sealing gaskets, and end plates. The stack is placed in a preloaded spring-based mechanical-compression system. This assembly is sealed within a stainless-steel vessel; the operating pressure of the reactants is balanced by the surrounding gas within the vessel, minimizing pressure differentials between the stack and its surroundings. The cross-cell pressure differential between the fuel and the air-steam electrodes brings the risk of cell fracture. Downstream electronic back-pressure regulators serve to maintain stable pressures throughout.The vessel, fuel side, and air side of the installation all have independently regulated flows at their respective inlets and a common regulated pressure at their outlets. Additional systems are in place to introduce steam, execute electrochemical characterizations, and monitor outlet flow rates. Furthermore, an in-line/in-situ mass spec and gas chromatograph provide continuous gas composition measurements.All of the integrated tools in the high-pressure installation are used to study hydrogen production in electrolysis mode, electricity production in fuel-cell mode, and chemical production using catalyst beds at the electrochemical reactor outlet. This powerful combination is very useful for optimizing the performance of electrodes and electrolytes at high pressure conditions and giving us new insight into the application of protonic-ceramic materials. Figure 1

High-temperature hydrogen production by solar thermochemical reactors, metal interfaces, and nanofluid cooling

Solar thermochemical reactors have been considered in recent studies because of converting the solar energy to a fuel, which is called solar fuel. In such reactors, heat transfer is a dominant phenomenon in generating products. Providing the optimum thermal energy for the solar thermochemical cycle can be gained by adjusting the size of the solar concentrator. In this study, the sizing of the solar concentrator is studied and the best size of the cavity is calculated by the Monte Carlo method. In this reactor using solar energy, the intermediate metal is converted to solar fuel. ZnO/Zn is considered to be the intermediate metal for the reaction. Next, the solar reactor is modeled in three dimensions and all types of heat transfer mechanisms, i.e., conduction, convection, and radiation along with chemical reaction conditions, are also considered. Sensitivity analysis is done based on the solar concentrator size and the aperture cavity. The results show that the optimum size of the dish collector is 5.168 m and the aperture cavity diameter was gained 5 cm for 10 kWth solar reactor. Nanofluid is used as cooling fluid, with the best modeled fluid flow rate for this structure, the ratio of annual fluid flow to nanofluid being 1. By examining the hydrogen production reactor, the amount of hydrogen produced in the system is 34 mol m−3. Also, the irradiation distribution of the cavity receiver and the temperature distribution of the solar reactor were modeled and analyzed.

Assessment of sustainable high temperature hydrogen production technologies

Apart from being a major feedstock for chemical production, hydrogen is also a very promising energy carrier for the future energy. Currently hydrogen is predominantly produced via fossil routes, but as green energy sources are gaining a larger role in the energy mix, novel and green production routes are emerging. The most abundant renewable hydrogen sources are water and biomass, which allow several possible processing routes, such as electrolysis, thermochemical cycles and gasification. By introducing heat to the process the required electricity demand can be reduced (high temperature electrolysis) or practically eliminated (thermochemical cycles). Each renewable hydrogen production route has its own strength and weaknesses; the choice of the most suitable method is always dependent on the economical potentials and the location. The aim of this paper is to evaluate the different high temperature, renewable hydrogen production technologies.

Application of spiking neural networks for modelling the process of high-temperature hydrogen production in systems with gas-cooled reactors *

Hydrogen energy is able to solve the problem of the dependence of modern industries on fossil fuels and significantly reduce the amount of harmful emissions. One of the ways to produce hydrogen is high-temperature water-steam electrolysis. Increasing the temperature of the steam involved in electrolysis makes the process more efficient. The key problem is the use of a reliable heat energy source capable of reaching high temperatures. High-temperature gas-cooled reactors with a gaseous coolant and a graphite moderator provide a solution to the problem of heating the electrolyte. Part of the heat energy is used for producing electrical energy required for electrolysis. Modern electrolyzers built as arrays of tubular or planar electrolytic cells with a nuclear energy source make it possible to produce hydrogen by decomposing water molecules, and the working temperature control leads to a decrease in the Nernst potential. The operation of such facilities is complicated by the need to determine the optimal parameters of the electrolysis cell, the steam flow rate, and the operating current density. To reduce the costs associated with the process optimization, it is proposed to use a low-temperature electrolysis system controlled by a spiking neural network. The results confirm the effectiveness of intelligent technologies that implement adaptive control of hybrid modeling processes in order to organize the most feasible hydrogen production in a specific process, the parameters of which can be modified depending on the specific use of the reactor thermal energy. In addition, the results of the study confirm the feasibility of using a combined functional structure made on the basis of spiking neurons to correct the parameters of the developed electrolytic system. The proposed simulation strategy can significantly reduce the consumption of computational resources in comparison with models based only on neural network prediction methods.

Применение спайковой нейронной сети для моделирования процесса высокотемпературного производства водорода в системах с газоохлаждаемыми реакторами

Применение спайковой нейронной сети для моделирования процесса высокотемпературного производства водорода в системах с газоохлаждаемыми реакторами

Thermodynamics analysis for high temperature hydrogen production system

Using clean energy sources is considered as a prevention solution for global warming. Hydrogen is one of the most popular clean and renewable fuel which is widely noticed by researchers in different approaches from additive fuel of internal combustion engines to pure feed of fuel cells. Hydrogen production is also one the most interested field of studies and extended efforts are doing to fined high performance, fast and economical ways of its production. In this work, a novel high temperature steam electrolysis system with main solar integrated Brayton cycle core is proposed and numerically simulated to achieve this goal. Energy and exergy analysis having better perception of system performance is done and Rankine and organic Rankine cycles were utilized cooperating with the main core to improve its efficiency. The influences of different parameters such as turbine inlet temperature, inlet heat flux from the sun, compression ratio and also used organic fluid were investigated based first and second laws. Results show the high performance of proposed system, more than 98% energy efficiency of hydrogen production, besides the simplicity of utilizing it.

Solar-driven high temperature hydrogen production via integrated spectrally split concentrated photovoltaics (SSCPV) and solar power tower

Hydrogen production can be achieved via combined concentrated photovoltaic (CPV) and concentrated solar power (CSP) in which concentrated radiation is spectrally split and then converted in a photovoltaic receiver and a thermal absorber. This study thus proposes an innovative solar process design integrating both thermal and quantum components of solar energy while providing a complete assessment of its global performance to demonstrate its practical interest. A stand-alone solar-to-hydrogen path was modeled and numerically simulated, which was both electrically and thermally supplied by a solar power generation unit to feed the electrolyzer power utilization unit with enhanced solar-to-hydrogen conversion efficiency. Following balance of plant (BoP), the heliostat field and cavity receiver were designed to match the entire system in which the receiver only intercepts a definite range of infrared wavelength while the rest is converted by separately insulated PV cells. Moreover, dichroic reflectors and optimum cutoff wavelength were applied to fulfill separate optimization and heat load reduction of each solar cell. Finally, the solid oxide electrolysis cell (SOEC) was designed to utilize the generated thermal and electrical power appropriately. In best case scenario, a solar-to-hydrogen conversion efficiency of 36.5% was achieved under 899 W/m2 direct normal irradiance (DNI) and 1000 suns concentration. The solar plant outputs at this operating point were 850 g/h H2 and 6754 g/h O2. Further improvement in efficiency can be achieved through alignment in regard to the site location and annual insolation variation.

Hydrogen production methods efficiency coupled to an advanced high-temperature accelerator driven system

Hydrogen, rather than oil, must be produced in volumes not provided by the currently employed methods. In this work, two high-temperature hydrogen production methods coupled with an advanced nuclear system are presented. A new design of a pebble-bed accelerator nuclear-driven system called TADSEA (Transmutation Advanced Device for Sustainable Energy Applications) was chosen because of the advantages in transmutation and safety. A detailed flowsheet of the high-temperature electrolysis process coupled to TADSEA through a Brayton gas cycle was developed using chemical process simulation software: Aspen HYSYS®. It is obtained 0.1627 kg/s of hydrogen with the model with optimized operating conditions, resulting in an overall process efficiency of 34.51%, a value in the range of results reported by other authors. A conceptual design of a plant using the iodine-sulfur thermochemical water splitting cycle was carried out producing 5.66e-2 kg/s and electric energy in cogeneration. The overall efficiency was calculated performing an energy balance resulting in 22.56%. A brief hydrogen production cost estimation was performed for both methods obtaining 5.96$/kg for the sulfur-iodine (SI) and 4.8 $/kg for the high-temperature electrolysis (HTE) process.

A Review of Projected Power-to-Gas Deployment Scenarios

Technical, economic and environmental assessments of projected power-to-gas (PtG) deployment scenarios at distributed- to national-scale are reviewed, as well as their extensions to nuclear-assisted renewable hydrogen. Their collective research trends, outcomes, challenges and limitations are highlighted, leading to suggested future work areas. These studies have focused on the conversion of excess wind and solar photovoltaic electricity in European-based energy systems using low-temperature electrolysis technologies. Synthetic natural gas, either solely or with hydrogen, has been the most frequent PtG product. However, the spectrum of possible deployment scenarios has been incompletely explored to date, in terms of geographical/sectorial application environment, electricity generation technology, and PtG processes, products and their end-uses to meet a given energy system demand portfolio. Suggested areas of focus include PtG deployment scenarios: (i) incorporating concentrated solar- and/or hybrid renewable generation technologies; (ii) for energy systems facing high cooling and/or water desalination/treatment demands; (iii) employing high-temperature and/or hybrid hydrogen production processes; and (iv) involving PtG material/energy integrations with other installations/sectors. In terms of PtG deployment simulation, suggested areas include the use of dynamic and load/utilization factor-dependent performance characteristics, dynamic commodity prices, more systematic comparisons between power-to-what potential deployment options and between product end-uses, more holistic performance criteria, and formal optimizations.

High temperature hydrogen production: Design of a 750 KW demonstration plant for a two step thermochemical cycle

The present work describes the study of a solar reactor for a two-step solar thermo-chemical water splitting cycle concerning the EU-project Hydrosol Plant, which aims to build a plant at the end of 2016 on a solar tower at the Plataforma Solar de Almería with a thermal input power of 750kW to produce 3kg/week of hydrogen. The process applies nickel-ferrite as reactive species, which works optimally at 1100°C for the water splitting step and at 1400°C for the regeneration step. This material is provided in form of monoliths which are used in cars as catalytic converter. On the platform three reactors are placed to reach a volume of about 0.3m3 of active material inside the reactor chambers. During the operations two of these will be regenerated while one will work on water splitting, to reach a quasi-continuous hydrogen production. The design concept of the reactor is taken from the SOLREF reactor, which was originally developed by DLR for methane reforming at 900°C and 10bar. The scheme and the layout of the plant to feed the reactors have been studied, too. A thermodynamic model for the regeneration step has been also developed to check if the thermal power demand of the three reactors can be supplied by the defined thermal input power. The differences to the other HYDROSOL projects are: The Upscaling from 100kW to 750kW, the usage of monoliths completely made of nickel-ferrite and the control strategy with three reactors instead of two.

High-temperature nuclear reactor power plant cycle for hydrogen and electricity production – numerical analysis

High temperature gas-cooled nuclear reactor (called HTR or HTGR) for both electricity generation and hydrogen production is analysed. The HTR reactor because of the relatively high temperature of coolant could be combined with a steam or gas turbine, as well as with the system for heat delivery for high-temperature hydrogen production. However, the current development of HTR’s allows us to consider achievable working temperature up to 750°C. Due to this fact, industrial-scale hydrogen production using copper-chlorine (Cu-Cl) thermochemical cycle is considered and compared with high-temperature electrolysis. Presented calculations show and confirm the potential of HTR’s as a future solution for hydrogen production without CO2 emission. Furthermore, integration of a hightemperature nuclear reactor with a combined cycle for electricity and hydrogen production may reach very high efficiency and could possibly lead to a significant decrease of hydrogen production costs.

Design and packaging of a highly integrated microreactor system for high-temperature on-board hydrogen production

The development of miniaturized reactors that can operate at high temperatures independently is always of great interest for many applications, especially in the area of portable hydrogen production. Here we present such microreactor systems, made of glass, with integrated heating and fluidic features based on thick-film technology. Key considerations on design, fabrication and packaging of our systems to achieve a high-temperature operation (>500°C), a thermal decoupling over 400°C for the device in the use of standard electrical/fluidic connections, as well as a simple catalyst installation method, are described. Demonstration of these “plug-and-play” microreaction systems is shown with producing hydrogen on-board from catalytic partial oxidation of propane at about 550°C (achieving 85% conversion of propane and 46.8% of hydrogen yield). The energy efficiency in comparison of the power consumption of electrical heating with the estimated energy produced from reformates shows a negative balance in the system under 30sccm feed of fuel/air mixture, indicating that a sufficient feed rate of fuel/air mixture is required for the system to achieve optimal energy balance. At an adequate level of the feed rate, the CPOX carried in our systems can even reach a thermally self-sustaining manner without needs of the electrical heating, which have been illustrated in our application development in micro-fabricated microreactors and micro-scale solid oxide fuel cells.