Korea, Republic of
Techno-economic Analysis of On-site Blue Hydrogen Production Based on Vacuum Pressure Adsorption: Practical Application to Real-world Hydrogen Refueling Stations
Feb 2023
Publication
Although climate change can be efficiently curbed by shifting to low-carbon (blue) hydrogen as an energy carrier to achieve carbon neutrality current hydrogen production mainly proceeds via the gray pathway i.e. generates large amounts of CO2 as a byproduct. To address the need for cleaner hydrogen production we herein propose novel CO2 capture processes based on the integration of vacuum pressure swing adsorption into a gray hydrogen production process and perform retrofitting to a blue hydrogen production process for on-site hydrogen refueling stations. Techno-economic analysis reveals that the implementation of the proposed capture processes allows one to significantly reduce CO2 emission while preserving thermal efficiency and the economic feasibility of this implementation in different scenarios is determined by computing the levelized cost of hydrogen. As a result blue hydrogen is shown to hold great promise for the realization of sustainable energy usage and the net-zero transition.
Spatiotemporal Analysis of Hydrogen Requirement to Minimize Seasonal Variability in Future Solar and Wind Energy in South Korea
Nov 2022
Publication
Renewable energy supply is essential for carbon neutrality; however technologies aiming to optimally utilize renewable energy sources remain insufficient. Seasonal variability in renewable energy is a key issue which many studies have attempted to overcome through operating systems and energy storage. Currently hydrogen is the only technology that can solve this seasonal storage problem. In this study the amount of hydrogen required to circumvent the seasonal variability in renewable energy supply in Korea was quantified. Spatiotemporal analysis was conducted using renewable energy resource maps and power loads. It was predicted that 50% of the total power demand in the future will be met using solar and wind power and a scenario was established based on the solar-to-wind ratio. It was found that the required hydrogen production differed by approximately four-times depending on the scenarios highlighting the importance of supplying renewable energy at an appropriate ratio. Spatially wind power was observed to be unsuitable for the physical transport of hydrogen because it has a high potential at mountain peaks and islands. The results of this study are expected to aid future hydrogen research and solve renewable energy variability problems.
Hydrogen Production in Methane Decomposition Reactor Using Solar Thermal Energy
Nov 2021
Publication
This study investigates the decomposition of methane using solar thermal energy as a heat source. Instead of the direct thermal decomposition of the methane at a temperature of 1200 ◦C or higher a catalyst coated with carbon black on a metal foam was used to lower the temperature and activation energy required for the reaction and to increase the yield. To supply solar heat during the reaction a reactor suitable for a solar concentrating system was developed. In this process a direct heating type reactor with quartz was initially applied and a number of problems were identified. An indirect heating type reactor with an insulated cavity and a rotating part was subsequently developed followed by a thermal barrier coating application. Methane decomposition experiments were conducted in a 40 kW solar furnace at the Korea Institute of Energy Research. Conversion rates of 96.7% and 82.6% were achieved when the methane flow rate was 20 L/min and 40 L/min respectively.
Progress and Challenges on the Thermal Management of Electrochemical Energy Conversion and Storage Technologies: Fuel Cells, Electrolysers, and Supercapacitors
Oct 2021
Publication
It is now well established that electrochemical systems can optimally perform only within a narrow range of temperature. Exposure to temperatures outside this range adversely affects the performance and lifetime of these systems. As a result thermal management is an essential consideration during the design and operation of electrochemical equipment and can heavily influence the success of electrochemical energy technologies. Recently significant attempts have been placed on the maturity of cooling technologies for electrochemical devices. Nonetheless the existing reviews on the subject have been primarily focused on battery cooling. Conversely heat transfer in other electrochemical systems commonly used for energy conversion and storage has not been subjected to critical reviews. To address this issue the current study gives an overview of the progress and challenges on the thermal management of different electrochemical energy devices including fuel cells electrolysers and supercapacitors. The physicochemical mechanisms of heat generation in these electrochemical devices are discussed in-depth. Physics of the heat transfer techniques currently employed for temperature control are then exposed and some directions for future studies are provided.
Development and Future Scope of Renewable Energy and Energy Storage Systems
May 2022
Publication
This review study attempts to summarize available energy storage systems in order to accelerate the adoption of renewable energy. Inefficient energy storage systems have been shown to function as a deterrent to the implementation of sustainable development. It is therefore critical to conduct a thorough examination of existing and soon-to-be-developed energy storage technologies. Various scholarly publications in the fields of energy storage systems and renewable energy have been reviewed and summarized. Data and themes have been further highlighted with the use of appropriate figures and tables. Case studies and examples of major projects have also been researched to gain a better understanding of the energy storage technologies evaluated. An insightful analysis of present energy storage technologies and other possible innovations have been discovered with the use of suitable literature review and illustrations. This report also emphasizes the critical necessity for an efficient storage system if renewable energy is to be widely adopted.
Research and Development Investment and Collaboration Framework for the Hydrogen Economy in South Korea
Sep 2021
Publication
South Korea developed its hydrogen strategies to achieve carbon neutrality and dominate the hydrogen economy amidst and with the impetus of the coronavirus disease 2019 (COVID-19) pandemic. The government strives toward the goal via continuous investment in green hydrogen technologies as well as strategic collaborations. To facilitate the transition into the hydrogen economy this study presents a research and development (R&D) investment and collaboration framework as a national strategy. The framework offers abundant information to elucidate the technology R&D spectrum and regional dimensions of the strategy. Furthermore the proposed framework was applied to the Korean hydrogen economy comprising 955 nationally funded projects worth USD 565.7 million. The statuses and trends of the government’s investment in nationally funded research projects are illustrated with regard to the value chains of the hydrogen economies of 16 regions as well as nine technology clusters relating to the hydrogen economy thereby determining the research organizations that played crucial roles in each cluster of the 16 regions between 2015 and 2020. The results indicate that the research organizations in Daejeon acquired the highest government R&D funding in many hydrogen-economy-related research fields and that an R&D spectrum-based research/strategic collaboration is required to accomplish specialized complexes in the regions.
Numerical Study of the Action of Convection on the Volume and Length of the Flammable Zone Formed by Hydrogen Emissions from the Vent Masts Installed on an International Ship
Nov 2021
Publication
International ships carrying liquefied fuel are strongly recommended to install vent masts to control the pressure of cargo tanks in the event of an emergency. However the gas emitted from a vent mast may be hazardous for the crew of the ship. In the present study the volume and length of the flammable zone (FZ) created by the emitted gas above the ship was examined. Various scenarios comprising four parameters namely relative wind speed arrangement of vent masts combination of emissions among four vent masts and direction of emission from the vent-mast outlet were considered. The results showed that the convection acts on the volume and length of an FZ. The volume of an FZ increases when there is a reduction in convection reaching the FZ and when strong convection brings hydrogen from a nearby FZ. The length of the FZ is also related to convection. An FZ is elongated if the center of a vortex is located inside the FZ because this vortex traps hydrogen inside the FZ. The length of an FZ decreases if the center of the vortex is located outside the FZ as such a vortex brings more fresh air into the FZ.
Complex Hydrides for Hydrogen Storage – New Perspectives
Apr 2014
Publication
Since the 1970s hydrogen has been considered as a possible energy carrier for the storage of renewable energy. The main focus has been on addressing the ultimate challenge: developing an environmentally friendly successor for gasoline. This very ambitious goal has not yet been fully reached as discussed in this review but a range of new lightweight hydrogen-containing materials has been discovered with fascinating properties. State-of-the-art and future perspectives for hydrogen-containing solids will be discussed with a focus on metal borohydrides which reveal significant structural flexibility and may have a range of new interesting properties combined with very high hydrogen densities.
Safe Ventilation Methods against Leaks in Hydrogen Fuel Cell Rooms in Homes
Jul 2022
Publication
Hydrogen which has a high energy density and does not emit pollutants is considered an alternative energy source to replace fossil fuels. Herein we report an experimental study on hydrogen leaks and ventilation methods for preventing damage caused by leaks from hydrogen fuel cell rooms in homes among various uses of hydrogen. This experiment was conducted in a temporary space with a volume of 11.484 m3 . The supplied pressure leak-hole size and leakage amount were adjusted as the experimental conditions. The resulting hydrogen concentrations which changed according to the operation of the ventilation openings ventilation fan and supplied shutoff valve were measured. The experimental results showed that the reductions in the hydrogen concentration due to the shutoff valve were the most significant. The maximum hydrogen concentration could be reduced by 80% or more if it is 100 times that of the leakage volume or higher. The shutoff valve ventilation fan and ventilation openings were required to reduce the concentrations of the fuel cell room hydrogen in a spatially uniform manner. Although the hydrogen concentration in a small hydrogen fuel cell room for home use can rapidly increase a rapid reduction in the concentration of hydrogen with an appropriate ventilation system has been experimentally proven.
Estimation of Liquid Hydrogen Fuels in Aviation
Sep 2022
Publication
As the demand for alternative fuels to solve environmental problems increases worldwide due to the greenhouse gas problem this study predicted the demand for liquid hydrogen fuel in aviation to achieve ‘zero‐emission flight’. The liquid hydrogen fuel models of an aircraft and all aviation sectors were produced based on the prediction of aviation fleet growth through the classification of currently operated aircraft. Using these models the required amount of liquid hydrogen fuel and the total cost of liquid hydrogen were also calculated when various environmental regulations were satisfied. As a result it was found to be necessary to convert approximately 66% to 100% of all aircraft from existing aircraft to liquid hydrogen aircraft in 2050 according to regulations. The annual liquid hydrogen cost was 4.7–5.2 times higher in the beginning due to the high production cost but after 2030 it will be maintained at almost the same price and it was found that the cost was rather low compared to jet fuel.
Machine Learning-based Energy Optimization for On-site SMR Hydrogen Production
Jun 2021
Publication
The production and application of hydrogen an environmentally friendly energy source have been attracting increasing interest of late. Although steam methane reforming (SMR) method is used to produce hydrogen it is difficult to build a high-fidelity model because the existing equation-oriented theoretical model cannot be used to clearly understand the heat-transfer phenomenon of a complicated reforming reactor. Herein we developed an artificial neural network (ANN)-based data-driven model using 485710 actual operation datasets for optimizing the SMR process. Data preprocessing including outlier removal and noise filtering was performed to improve the data quality. A model with high accuracy (average R2 = 0.9987) was developed which can predict six variables through hyperparameter tuning of a neural network model as follows: syngas flow rate; CO CO2 CH4 and H2 compositions; and steam temperature. During optimization the search spaces for nine operating variables namely the natural gas flow rate for the feed and fuel hydrogen flow rate for desulfurization water flow rate and temperature air flow rate SMR inlet temperature and pressure and low-temperature shift (LTS) inlet temperature were defined and applied to the developed model for predicting the thermal efficiencies for 387420489 cases. Subsequently five constraints were established to consider the feasibility of the process and the decision variables with the highest process thermal efficiency were determined. The process operating conditions showed a thermal efficiency of 85.6%.
Russia’s Policy Transition to a Hydrogen Economy and the Implications of South Korea–Russia Cooperation
Dec 2021
Publication
Leading countries are developing clean energy to replace fossil fuels. In this context Russia is changing its energy policy towards fostering new energy resources such as hydrogen and helium. Hydrogen will not only contribute to Russia’s financial revenue by replacing natural gas but will also provide a basis for it to maintain its dominance over the international energy market by pioneering new energy markets. Russia is aiming to produce more than two million tons of hydrogen fuel for export to Europe and Asia by 2035. However it is facing many challenges including developing hydrogen fuel storage systems acquiring the technology required for exporting hydrogen and building trust in the fuel market. Meanwhile South Korea has a foundation for developing a hydrogen industry as it has the highest capacity in the world to produce fuel cells and the ability to manufacture LNG: (liquefied natural gas) carriers. Therefore South Korea and Russia have sufficient potential to create a new complementary and reciprocal cooperation model in the hydrogen fuel field. This study examines the present and future of Russia’s energy policy in this area as well as discusses South Korea and Russia’s cooperation plans in the hydrogen fuel sector and the related implications.
Hydrogen Stress Cracking Behaviour in Dissimilar Welded Joints of Duplex Stainless Steel and Carbon Steel
Jun 2021
Publication
As the need for duplex stainless steel (DSS) increases it is necessary to evaluate hydrogen stress cracking (HSC) in dissimilar welded joints (WJs) of DSS and carbon steel. This study aims to investigate the effect of the weld microstructure on the HSC behaviour of dissimilar gas-tungsten arc welds of DSS and carbon steel. In situ slow-strain rate testing (SSRT) with hydrogen charging was conducted for transverse WJs which fractured in the softened heat-affected zone of the carbon steel under hydrogen-free conditions. However HSC occurred at the martensite band and the interface of the austenite and martensite bands in the type-II boundary. The band acted as an HSC initiation site because of the presence of a large amount of trapped hydrogen and a high strain concentration during the SSRT with hydrogen charging. Even though some weld microstructures such as the austenite and martensite bands in type-II boundaries were harmless under normal hydrogen-free conditions they had a negative effect in a hydrogen atmosphere resulting in the premature rupture of the weld. Eventually a premature fracture occurred during the in situ SSRT in the type-II boundary because of the hydrogen-enhanced strain-induced void (HESIV) and hydrogen-enhanced localised plasticity (HELP) mechanisms.
A Review on Industrial Perspectives and Challenges on Material, Manufacturing, Design and Development of Compressed Hydrogen Storage Tanks for the Transportation Sector
Jul 2022
Publication
Hydrogen fuel cell technology is securing a place in the future of advanced mobility and the energy revolution as engineers explore multiple paths in the quest for decarbonization. The feasibility of hydrogen-based fuel cell vehicles particularly relies on the development of safe lightweight and cost-competitive solutions for hydrogen storage. After the demonstration of hundreds of prototype vehicles today commercial hydrogen tanks are in the first stages of market introduction adopting configurations that use composite materials. However production rates remain low and costs high. This paper intends to provide an insight into the evolving scenario of solutions for hydrogen storage in the transportation sector. Current applications in different sectors of transport are covered focusing on their individual requirements. Furthermore this work addresses the efforts to produce economically attractive composite tanks discussing the challenges surrounding material choices and manufacturing practices as well as cutting-edge trends pursued by research and development teams. Key issues in the design and analysis of hydrogen tanks are also discussed. Finally testing and certification requirements are debated once they play a vital role in industry acceptance.
Carbon-free Green Hydrogen Production Process with Induction Heating-based Ammonia Decomposition Reactor
Dec 2022
Publication
This study presents an induction heating-based reactor for ammonia decomposition and to achieve a 150 Nm3 /h carbon-free green hydrogen production process. The developed metallic monolith reactor acts by increasing the reactor temperature through an electromagnetic induction method using renewable-based electricity. As a result hydrogen is produced without the generation of air pollutants such as CO2 which are formed via the conventional production pathway. Furthermore techno-economic analysis was conducted based on exergy and economic analysis to evaluate the feasibility of the developed process. Experimentally the proposed reactor showed an ammonia conversion of 90.0 % at 600 ℃ and 7 barg. Exergy analysis indicated that the total unused exergy accounted for 45.79 % of the total exergy input giving an exergy efficiency of 54.21 % for the overall process. Furthermore the CAPEX and OPEX values are calculated as 1599567 USD and 644719 USD/y respectively; therefore the levelized cost of hydrogen (LCOH) was calculated to be 6.98 USD/kgH2. This study also demonstrated that the LCOH varies with the ammonia feed price and the process capacity and so it would be expected to decrease from 6.98 to 5.33 USD/kgH2 as the hydrogen production capacity is increased from 150 to 500 Nm3 / h. Overall our results confirm the feasibility of carbon-free green hydrogen production on on-site hydrogen refueling stations and they will be expected to advance the development of an environmental hydrogen economy.
Bench-Scale Steam Reforming of Methane for Hydrogen Production
Jul 2019
Publication
The effects of reaction parameters including reaction temperature and space velocity on hydrogen production via steam reforming of methane (SRM) were investigated using lab- and bench-scale reactors to identify critical factors for the design of large-scale processes. Based on thermodynamic and kinetic data obtained using the lab-scale reactor a series of SRM reactions were performed using a pelletized catalyst in the bench-scale reactor with a hydrogen production capacity of 10 L/min. Various temperature profiles were tested for the bench-scale reactor which was surrounded by three successive cylindrical furnaces to simulate the actual SRM conditions. The temperature at the reactor bottom was crucial for determining the methane conversion and hydrogen production rates when a sufficiently high reaction temperature was maintained (>800 ◦C) to reach thermodynamic equilibrium at the gas-hourly space velocity of 2.0 L CH4/(h·gcat). However if the temperature of one or more of the furnaces decreased below 700 ◦C the reaction was not equilibrated at the given space velocity. The effectiveness factor (0.143) of the pelletized catalyst was calculated based on the deviation of methane conversion between the lab- and bench-scale reactions at various space velocities. Finally an idling procedure was proposed so that catalytic activity was not affected by discontinuous operation.
Investigation on the Changes of Pressure and Temperature in High Pressure Filling of Hydrogen Storage Tank
May 2022
Publication
Hydrogen as fuel has been considered as a feasible energy carry and which offers a clean and efficient alternative for transportation. During the high pressure filling the temperature in the hydrogen storage tank (HST) may rise rapidly due to the hydrogen compression. The high temperature may lead to safety problem. Thus for fast and safely refueling the hydrogen several key factors need to be considered. In the present study by the thermodynamics theories a mathematical model is established to simulate and analyze the high pressure filling process of the storage tank for the hydrogen station. In the analysis the physical parameters of normal hydrogen are introduced to make the simulation close to the actual process. By the numerical simulation for 50 MPa compressed hydrogen tank the temperature and pressure trends during filling are obtained. The simulation results for non-adiabatic filling were compared with the theoretically calculated ones for adiabatic conditions and the simulation results for non-adiabatic filling were compared with the simulation ones for adiabatic conditions. Then the influence of working pressure initial temperature mass flow rate initial pressure and inlet temperature on the temperature rise were analyzed. This study provides a theoretical research basis for high pressure hydrogen energy storage and hydrogenation technology.
Hydrogen Embrittlement of a Boiler Water Wall Tube in a District Heating System
Jul 2022
Publication
A district heating system is an eco-friendly power generation facility with high energy efficiency. The boiler water wall tube used in the district heating system is exposed to extremely harsh conditions and unexpected fractures often occur during operation. In this study a corrosion failure analysis of the boiler water wall tube was performed to elucidate the failure mechanisms. The study revealed that overheating by flames was the cause of the failure of the boiler water wall tube. With an increase in temperature in a localized region the microstructure not only changed from ferrite/pearlite to martensite/bainite which made it more susceptible to brittleness but it also developed tensile residual stresses in the water-facing side by generating cavities or microcracks along the grain boundaries inside the tube. High-temperature hydrogen embrittlement combined with stress corrosion cracking initiated many microcracks inside the tube and created an intergranular fracture.
Promising Technology Analysis and Patent Roadmap Development in the Hydrogen Supply Chain
Oct 2022
Publication
Hydrogen energy one of the energy sources of the future represents a substantial issue which affects the industries and national technologies that will develop in the future. In order to utilize hydrogen energy a hydrogen supply chain is required so that hydrogen can be processed and transported to vehicles. It is helpful for technology and policy development to analyze technologies necessary to charge the hydrogen energy generated into vehicles through the supply chain to discover technologies with high potential for future development. The purpose of this paper is to identify promising technologies required in storing transporting and charging vehicles generated by the hydrogen fuel supply chain. Afterward the promising technologies identified are expected to help researchers set a direction in researching technologies and developing related policies. Therefore we provide technology information that can be used promisingly in the future so that researchers in the related field can utilize it effectively. In this paper data analysis is performed using related patents and research papers for technical analysis. Promising technologies that will be the core of the hydrogen fuel supply chain in the future were identified using the published patents and research paper database (DB) in Korea the United States Europe China and Japan. A text mining technique was applied to preprocess data and then a generic topographic map (GTM) analysis discovered promising technologies. Then a technology roadmap was identified by analyzing the promising technology derived from patents and research papers in parallel. In this study through the analysis of patents and research papers related to the hydrogen supply chain the development status of hydrogen storage/transport/charging technology was analyzed and promising technologies with high potential for future development were found. The technology roadmap derived from the analysis can help researchers in the field of hydrogen research establish policies and research technologies.
An Overview of Water Electrolysis Technologies for Green Hydrogen Production
Oct 2022
Publication
Decarbonizing the planet is one of the major goals that countries around the world have set for 2050 to mitigate the effects of climate change. To achieve these goals green hydrogen that can be produced from the electrolysis of water is an important key solution to tackle global decarbonization. Consequently in recent years there is an increase in interest towards green hydrogen production through the electrolysis process for large-scale implementation of renewable energy based power plants and other industrial and transportation applications. The main objective of this study was to provide a comprehensive review of various green hydrogen production technologies especially on water electrolysis. In this review various water electrolysis technologies and their techno-commercial prospects including hydrogen production cost along with recent developments in electrode materials and their challenges were summarized. Further some of the most successful results also were described. Moreover this review aims to identify the gaps in water electrolysis research and development towards the techno-commercial perspective. In addition some of the commercial electrolyzer performances and their limitations also were described along with possible solutions for cost-effective hydrogen production Finally we outlined our ideas and possible solutions for driving cost-effective green hydrogen production for commercial applications. This information will provide future research directions and a road map for the development/implementation of commercially viable green hydrogen projects.
No more items...