Distributed Hydrogen Production Research Articles

A mathematical programming approach to export pathway planning of distributed hydrogen production in offshore wind farm

Hydrogen production is a vital development trend to improve the economics and penetration rate of offshore wind farms (OWFs), and distributed hydrogen production (DHP) is a preferred solution for deep and far sea OWFs without expensive submarine cables and offshore substations. The export pathway of OWF-DHP consists of collection pipelines, transmission pipelines, and offshore compressor stations. In this paper, mathematical programming is introduced to explore the export pathway planning problem of OWF-DHP. Firstly, the area of OWF is discretized into multiple grids with the center of the grids being the candidate locations of the offshore compressor station. Then, a binary integer quadratic programming problem is established to optimize both the offshore compressor station location and pipeline construction with different topologies. Further, the mathematical model is solved by the branch and cut algorithm integrated with the proposed dimension reduction methods. Finally, the effectiveness of the proposed export pathway planning approach is verified by the actual data of Baltic Eagle OWF in Germany, which would support the construction of the OWF-DHP project.

Rechargeable zinc-water battery for sustainable hydrogen generation

Metal-water primary batteries hold promise for distributed hydrogen production but suffer from limited renewability of metal electrodes in aqueous electrolytes. Here, we introduce a novel concept of a rechargeable zinc-water battery featuring a reversible zinc anode paired with a bifunctional water electrolysis electrode, realized in a specially designed aqueous electrolyte-a mild zinc triflate aqueous electrolyte with the addition of ethylenediaminetetraacetic acid disodium (EDTANa2). The system enables high-purity hydrogen production during discharge and high-purity oxygen production during charge in a membrane-free setup. In the zinc-water battery, EDTANa2 enhances the water-splitting electrode's performance by replacing hydrophobic OTF- anions, ensuring optimal water activity. Additionally, EDTANa2 enhances Zn electrode reversibility by chelating Zn2+, preventing solvated water decomposition during zinc deposition. This integrated battery continuously undergoes charge-discharge cycles for over 55 h at a current density of 6 mA cm-2. Moreover, it achieves a high hydrogen evolution rate of 12.5 mL cm-2 h-1, enabling cost-effective, high-purity hydrogen production without expensive membranes. These findings open new avenues for sustainable hydrogen generation and energy storage in nano energy systems.

Exploring decentralized ammonia synthesis for hydrogen storage and transport: A comprehensive CFD investigation with experimental validation and parametric study

Hydrogen energy plays a vital role in the transition towards a carbon-neutral society but faces challenges in storage and transport, as well as in production due to fluctuations in renewable electricity generation. Ammonia (NH3), as a carbon-neutral hydrogen carrier, offers a promising solution to the energy storage and transport problem. To realize its potential and support the development of a hydrogen economy, exploring NH3 synthesis in a decentralized form that integrates with distributed hydrogen production systems is highly needed. In this study, a computational fluid dynamics (CFD) model for the Ruthenium (Ru) catalysts-based Haber–Bosch reactor is developed. First, a state-of-the-art kinetic model comprehensively describing the complex catalytic reaction is assessed for its sensitivity and applicability to temperature, pressure and conversion. Then, the kinetic model is integrated into the CFD model, and its accuracy is verified through comparison with experimental data obtained from different Ru-based catalysts and operation conditions. Detailed CFD results for a given case are presented, offering a visual understanding of thermal gradients and species distributions inside the reactor. Finally, a CFD-based parametric study is performed to reveal the impacts of key operation parameters and optimize the NH3 synthesis reactor. The results show that the NH3 production rate is predominantly influenced by temperature, with a two-fold difference observed for every 30 °C variation, while pressure primarily affects the equilibrium. Additionally, the affecting mechanism of space velocity is thoroughly discussed and the best value for efficient NH3 synthesis is found to be 180,000 h−1. In conclusion, the CFD model and simulation results provide valuable insights for the design and control of decentralized NH3 synthesis reactor and operation, contributing to the advancement of sustainable energy technologies.

Heat Transfer and Reaction Characteristics of Steam Methane Reforming in a Novel Composite Packed Bed Microreactor for Distributed Hydrogen Production

The development of efficient and compact reactors is an urgent need in the field of distributed hydrogen production. Steam reforming of methane is the main method to produce hydrogen. Aiming at the problems of high heat and mass transfer resistance of the existing fixed bed reactors, and the difficulty of replacing the wall-coated catalyst in the microreactors, a composite packed bed was proposed to meet the demand of small-scale hydrogen production. The structure consists of a multi-channel framework with high thermal conductivity, which is filled with Ni/Al2O3 catalyst particles in each channel. A three-dimensional numerical model of the steam methane reforming process in the novel reactor was established using ANSYS FLUENT software. The heat transfer and reaction characteristics in the reactor were studied. Firstly, the advantages of the multi-channel skeleton in enhancing the radial heat transfer performance were verified by comparing it with the traditional randomly packed bed without the channel skeleton. Secondly, the influences of inlet velocity, inlet temperature, and heating wall temperature on the heat transfer and reaction performances in the reactor were studied, and a sensitivity factor was adopted to do the sensitivity analysis. The results show that the methane conversion rate is most sensitive to the wall temperature, while the inlet velocity and inlet temperature have less effect. Finally, the effects of two skeleton materials were studied. The results show that when the wall temperature is higher than 1200 K, there is no significant difference between these two reactors, which indicates that the use of cordierite with a lower price, but also with a lower thermal conductivity can significantly reduce the reactor’s cost. The conclusions can be used as a reference for the design of small-scale hydrogen production reactors.

Two-Layer Optimization Planning Model for Integrated Energy Systems in Hydrogen Refueling Original Station

With the aggravation of global environmental pollution problems and the need for energy restructuring, hydrogen energy, as a highly clean resource, has gradually become a hot spot for research in countries around the world. Facing the requirement of distributed hydrogen in refueling the original station for hydrogen transportation and other usage, this paper proposes a comprehensive energy system planning model for hydrogen refueling stations to obtain the necessary devices construction, the devices’ capacity decisions, and the optimal operation behaviors of each device. Comparing to traditional single hydrogen producing technics in the traditional planning model, the proposed model in this paper integrates both water-electrolysis-based and methanol-based manufacturing technics. A two-level optimization model is designed for this comprehensive system. The result of the numerical study shows that the proposed model can achieve a better optimal solution for distributed hydrogen production. Also, it considers the single producing situation when price of one primary resource is sufficient higher than the other.

Multi-objective optimization of hydrogen production process and steam reforming reactor design

This study proposes a multi-objective optimization approach to design a steam methane reforming (SMR) reactor and maximize the efficiency of the hydrogen production process. Out of 1782 possible variable combinations, only 50 iterations were performed, identifying three Pareto optimal that resulted in reactor size reductions of 50.53%, 35.56%, and 20.69%, respectively, compared to the reference reactor. The process efficiency for each optimal design varied slightly, with one achieving a 105.05% increase in efficiency, another remaining stable at 100.48%, and a third experiencing a slight decrease to 86.66% compared to the reference case. The results offer practical insights for planning an on-site distributed hydrogen production system, demonstrating that an increase in overall process efficiency can be achieved even with a reduced reactor size. This work is the first attempt to optimize a hydrogen production system by simultaneously considering overall process efficiency and SMR reactor design.

Improving the performances of supported NiCo catalyst for reforming of methane powered by magnetic induction

NiCo supported magnetic nanoparticles can catalyze the steam reforming of methane and at the same time provide the heat necessary to run the process by dissipating an external radio frequency electromagnetic field. Magnetic samples with different Ni:Co molar ratio and total metal loading on the support have been synthesized using a traditional impregnation procedure and characterized in terms of morphological and structural properties. The ability of the materials to provide process heat was assessed by temperature measurements. Methane conversion value and syngas composition have been measured for different applied field amplitude. The sample with a composition Ni50Co50_30 wt% was found to be the most performing in terms of conversion obtained with the same applied magnetic field. The developed magnetic catalysts contribute to the transition to distributed hydrogen production and help to tackle some of the challenges related to the intensification of production processes by electrification.

Effect of the Calcination Temperature of LaNiO3 on the Structural Properties and Reaction Performance of Catalysts in the Steam Reforming of Methane

The steam reforming of methane (SRM) reaction is a significant process for efficient syngas generation and for promising distributed hydrogen production. In this work, a series of LaNiO3 oxides were prepared using the Pechini method, calcined from 600 °C to 900 °C and tested for the SRM reaction. Fresh, reduced, and used samples were characterized using STA-MS-FTIR, in situ and ex situ XRD, N2 physical adsorption, H2-TPR, TEM, TPO, and Raman. The results show that LaNiO3 begins to crystallize at about 550 °C, and the increase in calcination temperature results in the following differences in the properties of the LaNiO3 samples: larger LaNiO3 grains, smaller specific surface area, higher reduction temperature, smaller Ni0 grains reduced from the bulk phase, and stronger metal–support interaction. The maximum CH4 conversion could be achieved over LaNiO3 calcinated at 800 °C. In addition, the effect of steam-to-carbon ratio (S/C) on the performance of the SRM reaction was studied, and a S/C of 1.5 was found to be optimal for CH4 conversion. Too strong a metal–support interaction and too much unreacted steam causes a loss of catalytic activity. Finally, it was also proved using TPO and Raman that an increase in calcination temperature improves the carbon deposition resistance of the catalyst.

Multi-hub hydrogen refueling station with on-site and centralized production

In recent decades, the consequences of climate changes due to greenhouse gas (GHG) emissions have become ever more impactful, forcing international authorities to find green solutions for sustainable economic development. In this regard, one of the global targets is the reduction of fossil fuels utilization in the transport sector to encourage the diffusion of more environmentally friendly alternatives. Among them, hydrogen is emerging as a viable candidate since it is a potentially emission-free fuel when produced by exploiting renewable energy sources (RES). Nevertheless, to allow widespread use of this gas in the transport sector, several technoeconomic barriers, including production cost, and lack of distribution and storage infrastructure, have to be overcome. Distributed hydrogen production via renewable energy-powered electrolysis could be an effective solution to reduce cost and lead to economies of scale. In this study a multi-hub configuration with on-site production from PV-powered electrolysis and centralized production from steam methane reforming (SMR) is proposed. In particular, an infrastructure network for a bus refueling station located in Lazio is considered as a case study. First, each hub, composed of PV panels, an electrolyzer, a compression system, high-pressure and low-pressure storages, and hydrogen dispensers with chiller, is modeled in a Matlab/Simulink environment. Then, a design perturbation analysis is carried out to determine the impact of the configuration on the refueling station performance in terms of carbon emissions levels and the Levelized Cost of hydrogen (LCOH). The results show a significant influence of the station size on the economic performance highlighting significant benefits (reduction up to 40% in the LCOH) for a 80 bus HUB with a saturating trend towards larger sizes. CO2 emissions per unit mass of hydrogen are kept limited for all the stations thanks to the synergistic effects of SMR and Electrolyzer. Interconnecting more than one station each other further benefits can be achieved from the environmental perspective (savings up to 5 tons of CO2 are demonstrated for a typical summer case study).

CO2-free hydrogen production via microwave-driven methane pyrolysis

Hydrogen will play an integral role in achieving net-zero emissions by 2050. Many studies have been focusing on green hydrogen, but this method is highly electricity intensive. Alternatively, methane pyrolysis can produce hydrogen without direct CO2 emissions and with modest electricity inputs, serving as a bridge from fossil fuels to renewable energies. Microwaves are an efficient method of adding the required energy for this endothermic reaction. This study introduces a new method of CO2-free hydrogen production via non-plasma methane pyrolysis using microwaves and carbon products of this process. Carbon particles in the fluidized bed absorb microwave energy and create a hot medium (>1200 °C) in contact with flowing methane. As a result, methane decomposes into hydrogen and solid carbon achieving over 90% hydrogen selectivity with ∼500 cumulative hours of experiments This modular pyrolysis system can be built anywhere with access to natural gas and electricity, enabling distributed hydrogen production.

One-pot synthesis of NiCo/MgAl2O4 catalyst for high coke-resistance in steam methane reforming: Optimization of Ni/Co ratio

NiCo bimetallic catalysts based on the support of a MgAl2O4 defect spinel (Mg/Al < 1/2) were developed as catalysts for steam methane reforming (SMR) in the present study. Catalysts were synthesized by the one-pot evaporation-induced self-assembly (EISA) method followed by exsolving of active components under reduction conditions. The optimum Co contents were found to be 5 wt% in NiCo-MgAl2O4 for the SMR catalysts with high activity and coking resistance. To understand the key parameters, the physicochemical properties of the catalysts were investigated by multiple analyses. Ni and Co were simultaneously exsolved from the A-site in the MgAl2O4 support after reduction, which led to formation of Ni-Co alloy with strong metal-support interaction. Co highly influenced the oxidation state of Ni where the relative concentration of Ni0 was highest (37.6 %) for NiCo5 (5 wt% of Co). Through SMR reaction tests and Raman and thermogravimetric (TG) analyses, it was clearly confirmed that the addition of Co in NiCo-MgAl2O4 enhances for catalytic efficiency and coke resistance. Our findings are highly applicable to the development of more robust and optimized catalysts, particularly in light of the future hydrogen economy and the related and increasing demand for small-scale SMR for distributed hydrogen production.

Design and operational considerations of packed-bed membrane reactor for distributed hydrogen production by methane steam reforming

Methane steam reforming will still account for most of hydrogen production in the coming decades. Membrane reactor can play a key role in both energy saving and process/equipment compactness, particularly for its decentralized applications. Here we design a particles-based packed-bed membrane reactor and explore the operational window and design challenges by conducting systematic study experimentally and computationally, particularly emphasizing geometrical scale of membrane reactor and catalyst activity. The results show that membrane reactor presents maximum hydrogen flux by consuming unit methane under the optimized operation conditions of GHSV (i.e., 1134 hr−1) and steam-to-carbon ratio (i.e., 2), and computational study shows that optimal operation window is around 30 atm and 773.15 K. Moreover, the design criteria of “Catalyst activity – Membrane performance – Radial depth” is revealed quantitatively and catalyst activity is identified as the key limiting factor for further process intensification. Briefly, these results shed some lights on operation, optimal design, and further improvement of membrane reactor in methane steam reforming.

Foam structured membrane reactor for distributed hydrogen production

Membrane reactor is one of the most potential methods for methane steam reforming process to achieve distributed hydrogen production. Mass, heat transfer and catalyst cost are the main hurdles to achieve its scaleup and practical applications. Here, we adopt structured foam SiC to construct Foam Structured Membrane Reactor (FSMR) and conduct systematic experimental study including catalytic reaction, membrane separation and integrated membrane reactor. The results indicate that FSMR can significantly intensify radial heat transfer (e.g., increase membrane side temperature about 20 °C) and radial mass transfer (e.g., faster H2 transfer to membrane) compared to conventional particles-packed membrane reactor (PMR). The mechanism is related to 3D continuous skeleton, cellular structure, and high thermal conductivity of structured solid foam. Also, FSMR can save more than 78% catalyst amount and achieve nearly 100% catalyst utilization efficiency.

Techno-economic analysis of hydrogen production electrically coupled to a hybrid desalination process

Climate change and resource scarcity have gained prominence with an increase in the world's population, necessitating the replacement of fossil fuels with eco-friendly alternatives. Here, to produce hydrogen sustainably, a combination of hybrid desalination with water electrolysis, to simultaneously produce hydrogen and pure water (with 4 MW plant capacity), has been proposed. The desalination produces additional electricity, which is used for high-temperature steam electrolysis (HTSE) using a solid oxide electrolysis cell (SOEC), and water electrolysis using an alkaline electrolysis cell (AEC). Reducing the electricity price, which accounts for almost the entire cost of hydrogen production, could decrease the cost of producing hydrogen. The system was verified by process simulation and optimization, along with economic and sensitivity analyses. The levelized cost of pure water was $1.08–1.86 per ton of water (reasonable compared to previous studies); the levelized cost of hydrogen ($1.75–5.32 and $0.63–2.35 per kg of H2 in SOEC and AEC, respectively) was significantly low, using the electricity generated by desalination. Therefore, this new small-scale paradigm producing pure water and hydrogen simultaneously could be an alternative to distributed hydrogen production, considering the difficulties of hydrogen storage and transportation.

Electrochemical Processes Role in the Drive for Industrial Decarbonization

Manufacturers are increasingly focused on meeting sustainability targets by decarbonizing their processes. Process electrification, exploiting the increasing amount of renewable power, is emerging as a viable tool for decarbonizing the chemical process industries (CPI). Electrochemical processing, together with process heating, and supported by electrical energy storage represent the key opportunities for innovation in process electrification.Electrochemical processing, using electrochemistry in place of or alongside traditional thermochemical or biochemical production methods, is already commonly used to produce aluminum, adiponitrile, chlorine, and caustic soda. Electrolysis is also used to produce hydrogen as a more sustainable alternative to steam methane reforming. Despite these commercial applications, electrochemical processing has not been applied broadly across the CPI due in part to slow development of electrodes, complex requirements for electrochemical cell fabrication and operation, and high capital and operating costs. However, spending on research and development in this area is increasing. Electrochemical reduction of carbon dioxide to C1 compounds (e.g., carbon monoxide, formic acid, and methanol) is demonstrated and scalable, and applied research on cell development for the production of C2 and higher compounds (e.g, ethylene, propylene, dimethyl ether, etc.) is accelerating. Development efforts must focus on demonstration of these process technologies at scale and over a range of operating conditions and feedstock qualities.Options for the future should include factory-produced, standardized modular platforms that enable cost-effective electrolysis. These platforms could become a mainstream process for distributed hydrogen production, a key requirement for carbon dioxide utilization. Similarly, electrochemical processing modules with various cell configurations could enable distributed carbon dioxide upgrading to C1 and higher compounds. Each of these cases will require development and demonstration of more efficient electromagnetic power sources and more robust electrode and membrane materials.

Techno-economic analysis and Monte Carlo simulation for green hydrogen production using offshore wind power plant

With the growth of marine energy such as offshore wind power, hydrogen is a promising solution for the intermittence of renewable energy sources and long-distance transmission. Some demonstration projects of offshore hydrogen production are underway using wind power. However, comparative studies on novel options such as individual hydrogen production and transport to land from each wind turbine, have not advanced beyond conceptual suggestion. In this study, to determine the most economical method of connecting offshore wind power plants and hydrogen production facilities, a techno-economic analysis of three offshore wind power plant arrangements is presented, including distributed hydrogen production, centralized hydrogen production, and onshore hydrogen production. As a method for feasibility comparison, net present value calculation, sensitivity analysis, and Monte Carlo simulation are suggested and analysis results for three arrangements are presented. In particular, the results of the proton exchange membrane electrolysis system model that is developed in the previous study are applied in order to determine the hydrogen production efficiency. Calculated hydrogen production cost was 13.81, 13.85, 14.58 $/kgH2 for distributed case, centralized case, and onshore hydrogen production case, respectively. The analysis results show that distributed case has the most competitive case due to the absence of expensive High Voltage Direct Current cable and offshore substation. Sensitivity analysis shows it is necessary to maintain capacity factor.

Centralized and distributed hydrogen production using steam reforming: challenges and perspectives

Centralized (left) and distributed (right) hydrogen production technologies using steam methane reforming are critically reviewed by capacity.

Plasma steam methane reforming (PSMR) using a microwave torch for commercial-scale distributed hydrogen production

Although large-scale hydrogen production through conventional steam methane reforming (SMR) is available at an affordable cost, there is a shortage of hydrogen pipeline infrastructure between production plants and fueling stations in most places where hydrogen is needed. Due to the difficulties of transporting and storing hydrogen, onsite hydrogen production plants are desirable. Microwave plasma torch-based methods are among the most promising approaches to achieving this goal.The plasma steam methane reforming (PSMR) method discussed here has many benefits, including a high energy yield, a small carbon footprint, real-time fueling because of the short start-up time (<10 min), and the absence of expensive metal-based catalysts. Methane reforming and water gas shift reaction (WGSR) co-occur in the method advanced without a separate WGSR to achieve a high H2 yield.This study examines an experimental investigation of commercial-scale hydrogen production through PSMR utilizing a microwave torch system. The optimum results obtained showed that the hydrogen production rate was 2247 [g(H2)/h], and energy yield was 70 [g(H2)/kWh] of the absorbed microwave power. An assessment of the results indicated a similar trend to that of simulated data (ASPEN Plus). The experimental results presented in this paper demonstrate the potential of a catalyst-free PSMR for commercial-scale hydrogen production.

(Invited) Design and Testing of a High-Pressure PEM Water Electrolyzer System Test Rig

Renewable energy-based hydrogen production via low temperature water electrolysis is attracting increased interest globally. Proton exchange membrane water electrolysis (PEMWE) offer several benefits over the more mature alkaline water electrolysis technology. The PEMWE-technology is particularly suitable for balancing variable power due to its great load-following capability. The PEMWE-technology can also be designed to operate at high current densities and pressures, which can reduce the system footprint and make the technology particularly suitable for distributed hydrogen production using solar PV energy. However, to reach the cost targets for green hydrogen more R&D on PEMWE stacks and systems is required to improve the overall system efficiency, durability, and capital costs.Institute for Energy Technology (IFE) has designed and built a flexible PEM water electrolyzer system platform for testing of small-scale prototype electrolyzers up to 33 kW and 200 bar differential pressure. This PEMWE system laboratory is part of a national research infrastructure on hydrogen and fuel cells in Norway (NFCH Centre) at the IFE Hynor Hydrogen Technology Center (IFE Hynor) at Kjeller. The PEMWE test rig is integrated with a sophisticated power conditioning system which consists of three custom-built DC/DC-converters (for PEMWE, PEMFC, and Li-ion battery systems), all coupled to the same DC-bus. This configuration makes it possible to use the Li-ion battery system to test different hybrid electric topologies for the water electrolyzer system and to emulate different loads (e.g., grid load profiles, solar PV input). IFE has also installed a 16 kWp PV-system on the roof of the IFE Hynor research building, which can be connected to the DC-bus on a need basis.The one-of-a-kind high-pressure PEMWE test facility at IFE is very well suited to study the performances of next-generation PEMWE stacks and systems, and to tailor and test control strategies that safeguard the system and maximizes efficiency and durability when operated using variable power based on renewable energy. The standard delivery pressure of PEMWE systems is today around 30 bar, but to realize H2-generation systems at several hundred bars there are several challenges related to system operability and safety that need to be addressed and solved. The first design of the high-pressure PEMWE test facility at IFE was first presented at a conference two years ago (EFCF 2019). The system has now been completed and commissioned with a state-of-art prototype high-pressure (350 bar) PEMWE stack with a production capacity of 2 Nm3/h. Details of the final design and operational procedures will be presented together with results and data from the first high-pressure PEMWE-stack test campaigns. Figure 1

Modeling and analysis of microchannel autothermal methane steam reformer focusing on thermal characteristic and thermo-mechanically induced stress behavior

The application of fuel cells boosts the hydrogen demand particularly for distributed hydrogen production facility. As a potential candidate of hydrogen supply, microchannel autothermal methane steam reactor operates at high temperature and results in high thermal impact, which would decrease its stability and lifespan. A three-dimension numerical model based on finite element method was developed to evaluate the thermal characteristic and thermo-mechanically induced stress behavior of the reactor. Three different potential manufacturing materials, Fe–Cr–Al alloy, ceramic and quartz, were chosen. The results indicate that the cold-spot temperature appears near reactor inlet while the hotspot temperature appears near reactor outlet for reactor manufactured by different materials. Corresponding to the hot spot temperature, the maximum Von Mises stress appears near reactor outlet. The difference is the maximum Von Mises stress appears in catalyst layer for quartz reactor while it appears in interconnect rib for both Fe–Cr–Al alloy reactor and ceramic reactor. Meanwhile the maximum Von Mises stress reaches 1830 MPa for ceramic reactor. While the maximum Von Mises stress is 1197 MPa for quartz reactor and 1760 MPa for Fe–Cr–Al alloy reactor respectively. It implies the outlet catalyst layer region is vulnerable for quartz reactor. While the outlet interconnect rib is most vulnerable for both Fe–Cr–Al alloy reactor and ceramic reactor.