Publications

Hydrogen energy is considered the most promising clean energy in the 21st century so hydrogen refuelling stations (HRSs) are crucial facilities for storage and supply. HRSs might experience hydrogen leakage (HL) incidents during their operation. Hydrogen-producing and refuelling integrated stations (HPRISs) could make thermal risks even more prominent than those of HRSs. Considering HL as the target in the HPRIS through the method of fault tree analysis (FTA) and analytic hierarchy process (AHP) the importance degree and probability importance were appraised to obtain indicators for the weight of accident level. In addition the influence of HL from storage tanks under ambient wind conditions was analysed using the specific model. Based upon risk analysis of FTA AHP and ALOHA preventive measures were obtained. Through an evaluation of importance degree and probability importance it was concluded that misoperation material ageing inadequate maintenance and improper design were four dominant factors contributing to accidents. Furthermore four crucial factors contributing to accidents were identified by the analysis of the weight of the HL event with AHP: heat misoperation inadequate maintenance and valve failure. Combining the causal analysis of FTA with the expert weights from AHP enables the identification of additional crucial factors in risk. The extent of the hazard increased with wind speed and yet wind direction did not distinctly affect the extent of the risk. However this did affect the direction in which the risk spreads. It is extremely vital to rationally plan upwind and downwind buildings or structures equipment and facilities. The available findings of the research could provide theoretical guidance for the applications and promotion of hydrogen energy in China as well as for the proactive safety and feasible emergency management of HPRISs.

This review explores the current status of green hydrogen integration into energy and industrial ecosystems. By considering notable examples of existing and developing green hydrogen initiatives combined with insights from the relevant scientific literature this paper illustrates the practical implementation of those systems according to their main end use: power and heat generation mobility industry or their combination. Main patterns are highlighted in terms of sectoral applications geographical distribution development scales storage solutions electrolyzer technology grid interaction and financial viability. Open challenges are also addressed including the high production costs an underdeveloped transport and distribution infrastructure the geopolitical aspects and the weak business models with the industrial sector appearing as the most favorable environment where such challenges may first be overcome in the medium term.

Hydrogen is a critical enabler of CO2 valorization essential for the synthesis of carbon-neutral fuels such as efuels and advanced biofuels. Biohydrogen produced from renewable biomass is a stable and dispatchable source of low-carbon hydrogen helping to address supply fluctuations caused by the intermittency of renewable electricity and the limited availability of electrolytic hydrogen. This study experimentally demonstrates that sorption-enhanced steam reforming (SESR) is a robust and adaptable process for hydrogen production from biomass-derived syngas-like gas streams. By incorporating in situ CO2 capture SESR overcomes the thermodynamic limits of conventional reforming achieving high hydrogen yields (>96 %) and purities (up to 99.8 vol%) across a wide range of syngas compositions. The process maintains high conversion efficiency despite variations in CO CH4 and CO2 concentrations and sustains performance even with H2-rich feeds conditions that typically inhibit reforming reactions. Among the operating parameters temperature has the greatest influence on performance followed by the steam-to-carbon ratio and space velocity. Multi-objective optimization shows that SESR can maintain high hydrogen yield (>96 %) selectivity (>99 %) and purity (>99.5 vol%) within a moderately flexible operating window. Methane reforming is identified as the main performance-limiting step with a stronger constraint on H2 yield and purity than CO conversion through the water–gas shift reaction. In addition to hydrogen SESR produces a concentrated CO2 stream suitable for downstream utilization or storage. These results support the potential of SESR as a flexible and efficient approach for hydrogen production from heterogeneous renewable feedstocks.

Anion exchange membrane (AEM) alkaline water electrolyser s are a promising reactor in large - scale industrial green hydrogen production. However the configurations of electrolysers especially the flow channel are not well optimised. In this work we demonstrate that the several existing flow channel designs e.g. single serpentine parallel pin can significantly affect the AEM electrolysers’ performance. The two -phase flow behaviours associated with the mass transfer of both electrolyte and produced gas bubbles within these flow channels have been simulated and thoroughly studied via a three -dimensional (3D) computational fluid dynamics (CFD) model . A novel flow channel design named Parpentine that combines the features of Parallel and Single serpentine designs is proposed with an optimised balance among the electrolyte flow distribution bubble removal rate and pressure drop. The superiority of the Parpentine flow channel is well verified in practical AEM water electrolyser experiments using commercial Ni foam and self-designed efficient NiFe and NiMo electrodes. At a cell voltage of 2.5 V compared to the benchmark serpentine design a 12.4% ~ 34.8% increase in hydrogen production efficiency can be achieved in both 1 M and 5 M KOH conditions at room temperature. This work discovers a novel design and a new method for highly efficient water electrolysers.

To address global CO2 emissions and the intermittency of renewables hydrogen is emerging as a promising carbon-free fuel for micro gas turbines (MGTs) offering potential for grid stability and decarbonization. However its high flame speed and adiabatic temperature present challenges including flashback and elevated NOx emissions. Conventional combustors often lack the compactness and NOx control needed for MGT-scale systems. This study numerically investigates pure hydrogen combustion in a compact MGT combustor using a secondary air dilution strategy. Based on the experimental setup of Tanneberger et al. simulations were conducted in ANSYS Fluent using steady-state RANS equations a CRECK-based chemical mechanism and the Flamelet Generated Manifold (FGM) model. The parametric study explores three design variables swirler blockage (B) central fuel tube length (C) and fuel injection split (S) along with five secondary air configurations (T1–T5). Results show that the secondary air hole pattern significantly affects flow structure and temperature uniformity. Configuration T1 provided the most uniform exhaust and lowest NOx emissions due to better air penetration and earlier dilution. Higher B and S increased local flame temperature intensifying thermal NOx via the Zeldovich mechanism. The findings offer design guidance for stable low-emission hydrogen combustors suitable for compact MGT applications.

The production of iron and steel plays a significant role in the anthropogenic carbon footprint accounting for 7% of global GHG emissions. In the context of CO2 mitigation the steelmaking industry is looking to potentially replace traditional carbon-based ironmaking processes with hydrogen-based direct reduction of iron ore in shaft furnaces. Before industrialization detailed modeling and parametric studies were needed to determine the proper operating parameters of this promising technology. The modeling approach selected here was to complement REDUCTOR a detailed finite-volume model of the shaft furnace which can simulate the gas and solid flows heat transfers and reaction kinetics throughout the reactor with an extension that describes the whole gas circuit of the direct reduction plant including the top gas recycling set up and the fresh hydrogen production. Innovative strategies (such as the redirection of part of the bustle gas to a cooling inlet the use of high nitrogen content in the gas and the introduction of a hot solid burden) were investigated and their effects on furnace operation (gas utilization degree and total energy consumption) were studied with a constant metallization target of 94%. It has also been demonstrated that complete metallization can be achieved at little expense. These strategies can improve the thermochemical state of the furnace and lead to different energy requirements.

In response to increasingly stringent emission regulations low-carbon fuels have received significant attention as sustainable energy sources for internal combustion engines. This study investigates four representative low-carbon fuels methane methanol hydrogen and ammonia by systematically summarizing their combustion characteristics and emission profiles along with a review of existing after-treatment technologies tailored to each fuel type. For methane engines unburned hydrocarbon (UHC) produced during lowtemperature combustion exhibits poor oxidation reactivity necessitating integration of oxidation strategies such as diesel oxidation catalyst (DOC) particulate oxidation catalyst (POC) ozone-assisted oxidation and zoned catalyst coatings to improve purification efficiency. Methanol combustion under low-temperature conditions tends to produce formaldehyde and other UHCs. Due to the lack of dedicated after-treatment systems pollutant control currently relies on general-purpose catalysts such as three-way catalyst (TWC) DOC and POC. Although hydrogen combustion is carbon-free its high combustion temperature often leads to elevated nitrogen oxide (NOx) emissions requiring a combination of optimized hydrogen supply strategies and selective catalytic reduction (SCR)-based denitrification systems. Similarly while ammonia offers carbon-free combustion and benefits from easier storage and transportation its practical application is hindered by several challenges including low ignitability high toxicity and notable NOx emissions compared to conventional fuels. Current exhaust treatment for ammonia-fueled engines primarily depends on SCR selective catalytic reduction-coated diesel particulate filter (SDPF). Emerging NOx purification technologies such as integrated NOx reduction via hydrogen or ammonia fuel utilization still face challenges of stability and narrow effective temperatures.

Fossil fuels have been the conventional source of energy that has driven economic growth and industrial development for a long time. However their extensive use has led to immense environmental problems especially concerning the emission of greenhouse gases. These problems have stimulated researchers to turn their attention to renewable alternative fuels. Hydrogen has risen in recent years as a prospective energy carrier because it is possible to produce it in an environmentally friendly manner and because it is the most common element. Hydrogen may be used in diesel engines in a dual-fuel mode. Hydrogen has a higher heating value flame speed and diffusivity in air. These superior fuel properties can enhance performance and combustion efficiency. Hydrogen can decrease carbon monoxide unburned hydrocarbons and soot emissions due to the absence of carbon in hydrogen. However hydrogen-fuelled diesel engines have problems such as engine knocking and high nitrogen oxide emission. This paper presents a comprehensive review of the recent literature on the performance combustion and emission characteristics of hydrogen-fuelled diesel engines. Moreover this paper discusses the long-term sustainability of hydrogen production methods nitrogen oxide emission reduction techniques challenges to the large-scale use of hydrogen economic implications of hydrogen use safety issues in hydrogen applications regulations on hydrogen safety conflicting NOx emission results in the literature and material incompatibility issues in hydrogen applications. This study highlights state-of-the-art developments along with critical knowledge gaps that will be useful in guiding future research. These findings can support researchers and industry professionals in the integration of hydrogen into both existing and future diesel engine technologies. According to the literature the use of hydrogen up to 46% decreased smoke emissions by over 75% while CO2 and CO emissions significantly decreased. Moreover hydrogen addition improved thermal efficiency up to 7.01% and decreased specific fuel consumption up to 7.19%.

This study investigates the interactive dynamics of directly injected (DI) hydrogen and methane jets with wall and neighboring jets in a non-reactive environment focusing on the influence of wave-shaped piston geometry. Experiments were conducted in a high-pressure optical chamber using a custom 2-hole DI injector with Schlieren imaging employed to capture the temporal evolution of jet structures for varying injection durations and injection pressure ratios. Comparative analyses between conventional flat and wave-shaped wall geometries reveals that the wave geometry significantly alters post-impingement jet behavior particularly enhancing jet guidance toward the center and promoting early detachment from the wall. For both hydrogen and methane jets impinging on the wave wall exhibited accelerated formation of a central flow structure akin to the radial mixing zone (RMZ) observed in reactive diesel combustion. This effect was most pronounced after end of injection where the trailing edge of the impinged jets in the wave geometry detached earlier and exhibited inward momentum forming U-shaped flow patterns indicative of efficient mixing. Quantitative jet area analysis further showed that the wave geometry confined and redirected the jets more effectively than the flat wall especially for hydrogen at shorter injection durations. These results demonstrate that the wave-piston concept originally developed for soot reduction in diesel engines also enhances jet-jet and jet-wall interaction efficiency in gaseous DI systems by promoting structured recirculation. Moreover these results suggest that wave-based piston geometries can substantially influence fuel-air mixing dynamics even in the absence of combustion providing a foundation for optimizing combustion chamber designs for low-carbon and high-diffusive gaseous fuels.

This study presents a thermodynamic equilibrium analysis of hydrogen-rich syngas production via biomass–methane co-pyrolysis employing the Gibbs free energy minimization method. A critical temperature threshold at 700 ◦C is identified below which methanation and carbon deposition are thermodynamically favored and above which cracking and reforming reactions dominate enabling high-purity syngas generation. Methane addition shifts the reaction pathway towards increased reduction significantly enhancing carbon and H2 yields while limiting CO and CO2 emissions. At 1200 ◦C and a 1:1 methane-tobiomass ratio cellulose produces 50.84 mol C/kg 119.69 mol H2/kg and 30.65 mol CO/kg; lignin yields 78.16 mol C/kg 117.69 mol H2/kg and 19.14 mol CO/kg. The H2/CO ratio rises to 3.90 for cellulose and 6.15 for lignin with energy contents reaching 43.16 MJ/kg and 52.91 MJ/kg respectively. Notably biomass enhances methane conversion from 25% to over 53% while sustaining a 67% H2 selectivity. These findings demonstrate that syngas composition and energy content can be precisely controlled via methane co-feeding ratio and temperature offering a promising approach for sustainable tunable syngas production.