Uranium thermochemical cycle used for hydrogen production

There exists a significant and growing need for clean, efficient, and large-scale hydrogen production. Using high temperature heat, thermochemical cycles can provide an energy-efficient route for hydrogen production. The Hybrid Sulfur process is a promising thermochemical watersplitting cycle with global-scale hydrogen production potential. The SO2-depolarized electrolyzer (SDE) is a critical component of the cycle. At the core of the electrolyzer is the membraneelectrode assembly, which consists of a solid electrolyte membrane sandwiched between two electrocatalyst layers. New electrocatalyst and membrane materials are being developed with the goals of improving the electrolyzer performance and extending the lifetime of the membrane-electrode assembly. A high-throughput methodology is being developed to screen potential candidates based on Pt and Au thin films prepared through physical vapor deposition. SO2 oxidation reaction kinetics are being analyzed for the novel catalysts and compared to the state-of-the-art, Pt/C. In addition, advanced polymer electrolyte membranes of polybenzimidazole (PBI) are utilized, which have shown superior performance in comparison to the state-of-the-art, Nafion®. These catalysts and membranes will be combined to produce high performance membrane-electrode assemblies.

Strategic examination of the classical catalysis of formic acid decomposition for intermittent hydrogen production, storage and supply: A review

Hydrogen production using high temperature nuclear reactors: Efficiency analysis of a combined cycle

Thermochemical cycles can provide a transformation mechanism for highly endothermic reactions at moderate temperatures and worthwhile yields but without the generation of waste streams. These have a general applicability but have been predominantly used for energy transformation from heat to stored chemical free energy in the form of hydrogen, with a view to a future hydrogen economy. Thermal efficiency is a key parameter in such a transformation, and the study presents a simple methodology for the determination of the limiting efficiency available, for the purpose of decision making in further cycle implementation and to develop consistency with other heat-to-work processes. The method is applied to 21 previously reported cycles, for which no such efficiency information has been reported, and discusses the features of the cycles which give rise to high and low efficiencies.

Energy and exergy analyses of magnesium-chlorine (Mg-Cl) thermochemical cycle

3.1 Hydrogen Production

In the present work, the feasibility of using a high temperature gas cooled nuclear reactor (HTR) for electricity generation and hydrogen production are analysed. The HTR is combined with a steam and a gas turbine, as well as with the system for heat delivery for medium temperature hydrogen production. Industrial-scale hydrogen production using copper-chlorine (Cu-Cl) thermochemical cycle is considered and compared with high temperature electrolysis. Presented cycle shows a very promising route for continuous, efficient, large-scale and environmentally benign hydrogen production without CO2 emissions. The results show that the integration of a high temperature helium reactor, with a combined cycle for electric power generation and hydrogen production, may reach very high efficiency and could possibly lead to a significant decrease of hydrogen production costs.

Neutronic analyses were performed in a hybrid reactor using 50% TRISO coated CANDU spent nuclear fuel and 50% Th mixture as fuel and natural Li as coolant. The XSDRNPM/SCALE nuclear code program was used for neutronic analyses. Under these conditions, the hybrid reactor operated for 48 months. TBR and M values were calculated from neutronic analyses. At the beginning of the 48-month operation period, the TBR value was approximately 1.176, while at the end of the operation period, this value was approximately 1.196. The M value was calculated as approximately 1.653 and 1.869 at the beginning and end, respectively. In addition, the amount of hydrogen production in the hydrogen production facility integrated into the reactor was examined. The vanadium-chloride (V-Cl) thermochemical cycle was preferred as the hydrogen production method. The approximate hydrogen production amount at the beginning and end of the 48-month operation period of the plant was calculated as 1,659 kg/s and 2,287 kg/s. As a result, it seems that the hybrid reactor and vanadium chloride (V-Cl) thermochemical cycle are preferable for hydrogen production

Hydrogen production by water splitting with Mn3-xCoxO4 mixed oxides thermochemical cycles: A thermodynamic analysis

Life cycle assessment of nuclear-based hydrogen and ammonia production options: A comparative evaluation

Thermochemical production of hydrogen from hydrogen sulfide with iodine thermochemical cycles

Hydrogen is a commercially important element. Basically, there are several methods of hydrogen production that have been commercially used, such as Steam Methane Reforming (SMR), High Temperature Steam Electrolysis (HTSE), and thermochemical cycles, like Sulphur-Iodine (SI). Among these methods, SMR is the most widely used for large-scale hydrogen production, with conversion efficiency between 74–85% and it has commercially used in some fertilizer industries in Indonesia. Steam reforming is a method to convert alkane (natural gas) compounds to hydrogen and carbon dioxide (synthetic gas) by adding moisture at high pressure and temperature (35-40 bar; 800-900°C). These hydrogen production technologies can be coupled with different nuclear reactors based on the heat required in the process. The High Temperature Gas-cooled Reactor (HTGR) using helium as a coolant, has a high outlet temperature (900°C), so it can potentially be used to supply for process heat for hydrogen production, coal liquefaction/gasification or for other industrial processes requiring high temperature heat. Hydrogen production cost from SMR method is influenced by a range of technical and economic factors. The fuel component of natural gas needed in the SMR method can be replaced by nuclear heat from a nuclear power plant (NPP) operating in cogeneration mode (i.e. simultaneous producing electric power and heat), hence contributing to the reduction of carbon dioxide in the process.In the SMR method, fuel costs are the largest cost component, accounting for between 45% and 75% of production costs. Therefore, there is opportune to assess the economics of hydrogen production by using nuclear heat. The economic evaluation is done by using IAEA HEEP-4 Software.The results comprise cost break up for 2 cases, coupling SMR process for hydrogen production with: (1) 2 HTGRs of 170 MWth/unit; and (2) 1 HTGR of 600 MWth/unit. The cost of hydrogen production is highly depend on the scale of the NPP as energy source and results indicated that hydrogen production cost of the 1 HTGR Unit600 MWth (Case 2) has a lower value (1.72 US$/kgH2), than the cost obtained when 2 HTGR units of 170 MWth each (case 1) are considered (2.72 US$/kgH2). For comparison, the hydrogen production cost by using SMR with carbon capture and storage (CCS) with natural gas as fuel is 2.27 US$/kgH2.

Economic comparison of solar hydrogen generation by means of thermochemical cycles and electrolysis

A novel cryogenic-thermochemical approach for clean hydrogen production from industrial flue gas streams with carbon capture and storage

Hydrogen production via a two-step water splitting thermochemical cycle based on metal oxide – A review