Hydrogen Volume Research Articles

Hydrogen capture using zeolite 3A for pipeline gas deblending

Less than 20% of hydrogen gas can be co-transported with natural gas (NG) and distributed to end-users using existing gas pipelines. However, most industrial gas turbines can only tolerate up to 1% by volume of hydrogen in natural gas. A separation process is needed to selectively capture the minor component such as hydrogen. Herein, we report the design of a deblending process to meet the requirements of these specific industries. We demonstrated that zeolite 3A which is believed to be a trapdoor zeolite has a selectivity towards hydrogen molecules based on the laboratory experiment results. A multiple-bed pressure swing adsorption (PSA) using zeolite 3A was subsequently modelled for removing hydrogen at various concentrations from the blended gas. The results indicate that high pressure and high purity methane (>99%) can be obtained by the 3A PSA, making products suitable for gas turbines. When a methane PSA with activated carbon (AC) adsorbents is used for comparison, the process needs to do separation work towards the major component methane and an overwhelming pump work is required to repressurize the desorbed methane gas. Therefore, a hydrogen capture PSA process with zeolite 3A stands out in terms of product purity, recovery and energy consumption, for low concentration H2 deblending from NG.

Математическое моделирование натекания водорода в гермзоне реакторного здания АЭС с ВВЭР-1200

Introduction. The patterns of hydrogen-air mixtures formation during the flow of hydrogen into the upper part of a large volume room in the initial moments of time are insufficiently studied. Therefore, the determination of regularities of formation of local explosive and fire-hazardous hydrogen-air mixtures when hydrogen flows into the lower part of the dome space of the reactor building is important. Goals and objectives. The purpose of the article is a theoretical study of occurrence of local fire and explosive zones of the hydrogen-air mixture generated during hydrogen leakage in the containment area of the reactor building in order to substantiate parameters of concentration sensors of the hydrogen concentration control system. To achieve it, a zone mathematical model of hydrogen concentration calculation in a pressurized room has been developed. Numerical experiments on regularities of hydrogen-air mixtures formation have been carried out. Theoretical basis. The generalized three-dimensional non-stationary differential equation of the laws of conservation of mass, momentum and energy is used to calculate local hydrogen concentration fields. The developed zone model makes it possible to determine hydrogen concentrations in the convective column and in the ceiling layer. Results and discussion. The characteristic fields of hydrogen mass concentrations in the volume of the dome space are obtained. It has been shown that at the initial stage of hydrogen leakage, a zone of the ceiling layer is formed under the ceiling of the dome space, which confirms the validity of the usage of the zone model. The hydrogen concentrations obtained by the field and zone models are compared. The distributions of hydrogen mass concentration along the convective column height at different Reynolds numbers in the hydrogen leakage hole have been obtained. It has been shown that hydrogen concentration sensors can detect a hydrogen leakage mode in the dome space only in a narrow area of Reynolds Re = 900–5,000. There is a leakage mode (Re = 3,358), in which the maximum hydrogen volume concentration is generated at the location of the concentration sensors at the maximum size of the fire and explosive hydrogen-air mixture zones in the room. Conclusions. The hydrogen concentration sensors used in the dome space of the NPP reactor building with water-­water reactors may not detect hydrogen at the top point of the dome at a sensitivity threshold of 2 % vol. In this case, in terms of the height of the convective column, hydrogen-air mixtures are formed within the fire and explosive concentration limits.

Comparative analysis of compressed hydrogen losses during its transportation through the pipelines from different materials

The authors estimate possible losses of transported compressed hydrogen (P = 10 MPa) due to diffusion through the pipe wall applying Sieverts law and Arrhenius equation and using tabular data on the coefficients of permeability and solubility. The calculation was carried out for pipelines made of various metallic and non-metallic materials at room and elevated temperatures. It is shown that the volume of the diffused gas at T = 298°K (25°С) is only fractions of a percent of the pumped hydrogen volume. At the same time, the biggest loss occurs in a pipeline made of polyethylene (~0.03%), and the most insignificant one in austenitic steels (~10-6%). For carbon and low-alloy steels, the main materials of gas pipelines, these losses are at the level of 10-4–10-5 %. When the temperature rises to 683°K (410°C), the losses in steel pipelines increase to 0.25%, in polymer pipelines to 20%.

Effects of longitudinal excitation on liquid hydrogen sloshing in spacecraft storage tanks under microgravity conditions

Based on the real physical model and operating environment of the spacecraft tank, the numerical model of the tank is established and the sloshing behavior of liquid hydrogen in the tank under different longitudinal excitations is studied in this work. The Realizable k- ε model is used to predict the fluid turbulence, and the mixture model is used to analyze the phase transitions and flows. The harmonic external excitation is loaded by the user-defined function (UDF). Based on the CFD sloshing model verified through comparison with experimental results, the influences of different longitudinal external excitation frequencies and amplitudes on the liquid hydrogen volume fraction in the tank are firstly analyzed. On this basis, including pressure and other physical quantities of the monitoring points and whole internal fluid domain during the sloshing simulation process are studied quantitatively. In addition, the relationship between the carrier amplitude of the sloshing curves and the external excitation amplitude is discussed. The simulation results show that in microgravity environment, compared with large amplitude excitation, high-frequency longitudinal harmonic excitation has a significant effect on the variation of physical parameters in the tank, which may become a negative factor for the safety of liquid hydrogen storage and supply systems. Meanwhile, the traditional baffle design has a limited influence on the liquid hydrogen motion under the high-frequency longitudinal excitation which may occur during the spacecraft changing load process. The results provide valuable information for the understanding of sloshing behavior and safety evaluation of the tank under longitudinal excitation.

Compressor speed control design using PID controller in hydrogen compression and transfer system

Hydrogen is an energy carrier which can be processed by high pressure compressor and they can be transported, stored and converted to electricity for later use. This paper proposes a hydrogen compression model development and modeling of hydrogen transportation between two tanks using MATLAB software version 22. The proposed model provides amount of hydrogen required in volumes (m3) and compressor power required in (KW) for compressor speed of 500 rad/s, 1000 rad/s and 1500 rad/s. This model provides hydrogen volume of 1 m3 and 10 KW compressor power requirement at 500 rad/s compressor speed. For compressor speed of 1000 rad/s, the proposed model provides hydrogen volume of 10 m3and 20 KW compressor power requirements and for 1500 rad/s this model provides volume of 30 m3and 30 KW compressor power requirements which indicates that the increase in compressor speed increases hydrogen volume generated and increase the power requirement also. For maintaining compressor speed at desired value, a PID (Proportional + Integral + Derivative) controller has been designed and the results were compared with Proportional (P), PI (Proportional + Integral), and PD (Proportional + Derivative) controllers. PID controller performance can be measured using the parameters delay time and settling time. Low values of settling time and delay time indicate the better performance of PID controller. P controller achieves the desired compressor speed with delay time of 228 ms; settling time of 1250 s. PI controller achieves the desired compressor speed with delay time of 210 ms, settling time of 1210 s. PD controller achieves the desired compressor speed with delay time of 185 ms, settling time of 1280 s. PID controller provides better speed regulation with low delay time of 110 ms and settling time of 1120 s when compared with P, PI, PD controllers. From the simulation results it is observed that PID controller can be a good option for slow process like hydrogen gas flow through pipeline for effective speed regulation.

Synthesis of cobalt-doped catalyst for NaBH4 hydrolysis using eggshell biowaste

In the present study, a cobalt-doped catalyst was prepared from chicken eggshell powder (CEP) biowaste to be used in the hydrolysis of sodium borohydride (NaBH4). In the presence of the prepared catalyst (CEPcat), possible effects of the parameters of NaOH concentration (%), catalyst amount (g), NaBH4 concentration (%), process temperature (oC) and reusability affecting the hydrolysis of sodium borohydride were examined. The CEPcat obtained was characterized with FT-IR, TGA, XRD, SEM and EDX analyses. The hydrogen generation rate (HGR) was determined as 432 mL gCo−1 min−1 in the presence of 1 g CEPcat, a CoO/CaO ratio of 10/90 and 1% NaBH4 concentration. The activation energy of the NaBH4 hydrolysis reaction was calculated as 16.78 kJ mol−1. After 16 reuses of the CEPcat there was no significant decrease in the hydrogen volume. Compared to the first use while there was an increase in the HGR. These results showed that the CEPcat prepared has a significant advantage over other catalysts for use in NaBH4 hydrolysis.

Optimizing green hydrogen production: Leveraging load profile simulation and renewable energy integration

As our world continues to rapidly industrialize and our population grows at an unprecedented rate, the energy demands have become one of the primary drivers for economic growth. However, the availability of traditional fossil fuels is limited and their use leads to serious environmental problems. Recently, in the last few decades, many developments have been made in the area of energy efficiency driven by non-conventional energy sources. So, inclination towards renewables such as solar (PV) energy, wind power, hydro energy, bio-fuels, bio/green-hydrogen, etc., seems to be a feasible alternative in the coming future. Technology alternatives dealing with fuel cells appears to be a promising approach to fulfil the ever-exceeding energy requirements. The purpose of the present research is to extract information about the working principle and applications of renewable energy technologies such as photo-electrolysis, photovoltaic power, wind power, electrolyzer for hydrogen generation, fuel cells for power generation and also to gain knowledge for the future research and improvements for the renewable technology systems. All the experiments are conducted with the help of Heliocentric, the kit for green and clean energy trainer technology. Here the energy efficiency for the system is found to be ∼86% with a hydrogen volume of 30 cm3 and a time of 174 s (∼3 min). Similarly, for a system with 25 cm3 of hydrogen volume and a time of 110 s, the efficiency calculated is around ∼36%. The research work outcomes are anticipated to help in the clear understanding of renewable energy technologies and their integration to produce sustainable, green and clean energy.

Enhanced photocatalytic activity through anchoring and size effects of Au nanoparticles on niobate nanotubes and nanosheets for water splitting

The inorganic semiconducting potassium hexaniobate (K4Nb6O17) has a wide band gap of 3.4 eV and has been widely studied as a photocatalyst activated by the ultraviolet part of the solar spectrum. In this study, we have prepared nanotubes and nanosheets of H4Nb6O17 and attached Au nanoparticles of two different sizes to both. The resultant composites are characterised and their activity towards H2 generation by photocatalytic water splitting is investigated. We found that the morphology of the nano-niobate had minimal effect for the Au particles attached directly to the niobate, however for the (3-Aminopropyl) triethoxysilane (APTES) anchored Au particles a marked difference in their activities towards water splitting was observed. The APTES-Au-nanosheets produced a maximum volume of hydrogen of 1384.3 μmol g−1 h−1, which was much higher than the 36.9 μmol g−1 h−1 for the parent niobate nanotubes. Morphology and different interaction were considered as the main factors affecting photocatalytic efficiency.

First-principles quantum computations to investigate prospects of Mg2FeH6 for optoelectronics and hydrogen-storage applications

To overcome the growing energy crisis and hazardous effect of conventional energy sources on environment and inhabitants, hydrogen has been proposed as an excellent alternative clean energy source. In particular, the storage of hydrogen in solid-state materials and its on-demand release for potential energy applications is the novel energy-efficient technology. In this regard, metal hydrides have shown promising hydrogen-storage capacity. However, high gravimetric and volumetric density, low thermodynamic stability, and high kinetics of metal hydrides is vital to enhance the hydrogen storage and releasing efficiency at routine temperature and pressure. In this regard, Mg2FeH6 has shown promise on hydrogen-storage applications on account of its high hydrogen volume density 150 kg m−3 (more than double that of liquid hydrogen), and a gravimetric hydrogen density of 5.66 wt%. In this work, we first time employed first-principles density functional (DFT) approach within GGA + U methodology to investigate the structural, electronic, magnetic, and optical properties of Mg2FeH6. Our computed results revealed wide band gap semiconductor nature of Mg2FeH6 having a direct band gap of 3.194 eV at point X. As revealed by the DFT analysis, Mg2FeH6 was magnetic in ground state with magnetic moment 6.40 μB. The calculated optical properties include dielectric constants, absorption coefficient, reflectivity, energy loss function, and refractive index. The structural properties agree with experimental/theoretical results while electronic and optical properties differ considerably from the available theoretical data computed with different methods.

Effect of relative permeability hysteresis on reservoir simulation of underground hydrogen storage in an offshore aquifer

Underground hydrogen storage (UHS) in porous media is proposed to balance seasonal fluctuations between demand and supply in an emerging hydrogen economy. Despite increasing focus on the topic worldwide, the understanding of hydrogen flow in porous media is still not adequate. In particular, relative permeability hysteresis and its impact on the storage performance require detailed investigations due to the cyclic nature of H2 injection and withdrawal. We focus our analysis on reservoir simulation of an offshore aquifer setting, where we use history matched relative permeability to study the effect of hysteresis and gas type on the storage efficiency. We find that omission of relative permeability hysteresis overestimates the annual working gas capacity by 34 % and the recovered hydrogen volume by 85 %. The UHS performance is similar to natural gas storage when using hysteretic hydrogen relative permeability. Nitrogen relative permeability can be used to model the UHS when hysteresis is ignored, but at the cost of the accuracy of the bottom-hole pressure predictions. Our results advance the understanding of the UHS reservoir modeling approaches.

Effects of Hydrogen/Methane on the Thermal Environment of Heavy-Duty Gas Turbine Combustor

Hydrogen is the most promising fuel for reducing carbon emissions, but hydrogen combustion produces higher temperature compared to hydrocarbon fuel. In this paper, a three-dimensional compressible combustion–flow–heat transfer model of combustor was established, and a dry-low-emission combustor was examined by using the realizable model, transported probability density function, and discrete ordinates model combining weighted sum of gray gas model, analyzing the effects of hydrogen/methane blended fuel and thermal boundaries on the combustor thermal environment. The results show that when the fuel hydrogen volume percentage increases from 0 to 75%, the maximum gas temperature and concentration on the central axis of the combustor increase by about 160.8 and 662.9%, respectively; the maximum incident radiant heat flux of the combustor wall increases by about 150%; and the local maximum ratio of the radiant heat transfer to the total heat transfer through the wall increases from about 34 to about 49%. The effect of the boundary conditions varies depending on the hydrogen percentage. At the hydrogen percentage of 75%, the maximum wall-incident radiant heat flux under the adiabatic condition is nearly 180.3 and 77.4% higher than the values at 1370 and 1920 K isothermal boundaries, respectively.

The Study of 2, 4-Diamino-6-methly-1, 3, 5-triazine on the Corrosion Inhibition of Mild Steel in The Hydrochloric Acid Medium: Integrated Theoretical and Experimental Investigations

The aim of this study is the investigation of adsorption and corrosion behaviors of 2,4-Diamino-6-methly-1,3,5-triazine (2-DMT) on mild steel (MS) in 0.5 M HCI solution using many experimental and theoretical studies such as potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), linear polarization resistance (LPR), adsorption isotherm, potential of zero charge (PZC), scanning electron (SEM), atomic force microscopies (AFM) and quantum chemical calculations. The results showed that 2-DMT has an outstanding anti-corrosion performance of 94.6% at an optimum concentration of 10 mM and the MS surface, which was exposed to the inhibited solution at 298 K, does not contain pits, cracks or deformations. Values of icorr are found to be 0.51, 0.22, 0.098, 0.072 and 0.039 mA cm-2 for blank solution and each concentration of 2-DMT. Hydrogen volumes are 90 and 4.6 mL cm-2 for blank solution and the existence of 10.0 mM 2-DMT, respectively. The observed adsorption is much more consistent with Langmuir. The high performance is explained by the effective adsorbing of organic matter to the MS surface. HOMO, LUMO energies and the energy gap (∆E) are -7.1980, -1.9959 and 5.2021 eV, respectively. Accordingly, it is suggested that this organic compound can be used in the industrial acid cleaning procedure.

Design and research of soft-body cavity-type detonation drivers

According to the high-energy-density movement characteristics of animals during jumping, soft-body cavity-type detonation driver that combines the explosive chemical reaction mechanism of hydrogen and oxygen is designed, in order to control the robot in jump to achieve output optimization. Then, combined with the theoretical values of the detonation dynamic equation and experimental data for the performance parameters, the influences of the mixing ratio of hydrogen (H2) and oxygen (O2), the volume of mixed hydrogen and oxygen in the cavity, and the shape, wall thickness, and area ratio value of the soft-body cavity on the output performance of the detonation driver are analyzed. When gas volume is 20:10mL, the jump height reaches 2.5m. In addition, the upper and lower area ratio of cavity is optimized to 2:1, improving the output performance by 21.6% on average. Therefore, the above research results provide reference for the driver structure design of jumping robot.

Safe Design of a Hydrogen-Powered Ship: CFD Simulation on Hydrogen Leakage in the Fuel Cell Room

Adopting proton exchange membrane fuel cells fuelled by hydrogen presents a promising solution for the shipping industry’s deep decarbonisation. However, the potential safety risks associated with hydrogen leakage pose a significant challenge to the development of hydrogen-powered ships. This study examines the safe design principles and leakage risks of the hydrogen gas supply system of China’s first newbuilt hydrogen-powered ship. This study utilises the computational fluid dynamics tool FLACS to analyse the hydrogen dispersion behaviour and concentration distributions in the hydrogen fuel cell room based on the ship’s parameters. This study predicts the flammable gas cloud and time points when gas monitoring points first reach the hydrogen volume concentrations of 0.8% and 1.6% in various leakage scenarios, including four different diameters (1, 3, 5, and 10 mm) and five different directions. This study’s findings indicate that smaller hydrogen pipeline diameters contribute to increased hydrogen safety. Specifically, in the hydrogen fuel cell room, a single-point leakage in a hydrogen pipeline with an inner diameter not exceeding 3 mm eliminates the possibility of flammable gas cloud explosions. Following a 10 mm leakage diameter, the hydrogen concentration in nearly all room positions reaches 4.0% within 6 s of leakage. While the leakage diameter does not impact the location of the monitoring point that first activates the hydrogen leak alarm and triggers an emergency hydrogen supply shutdown, the presence of obstructions near hydrogen detectors and the leakage direction can affect it. These insights provide guidance on the optimal locations for hydrogen detectors in the fuel cell room and the pipeline diameters on hydrogen gas supply systems, which can facilitate the safe design of hydrogen-powered ships.

Organic-rich source rock/H2/brine interactions: Implications for underground hydrogen storage and methane production

There is increasing global interest in the attainment of a carbon dioxide-free global economy by replacement of carbon-based fossil fuels with clean hydrogen. But huge volume of hydrogen needs to be stored to address the imbalance between energy demand and supply due to low volumetric energy content of H2. Underground Hydrogen Storage (UHS) is an integral part of the hydrogen economy value chain and an appealing technology for the attainment of global decarbonization. The Jordan oil shale (Upper Cretaceous, organic-rich source rock sequence) has been proposed as a promising geological storage medium for hydrogen due to its exceptionally high organic content because methane can be produced from the reaction of trapped hydrogen with the kerogen. However, the extraction of methane from kerogen during hydrogen storage in organic-rich shale has not yet been reported. In this study, pressurized hydrogen was injected into high TOC shale samples for 80 days at 1500 psi and 75 °C to assess the extent of hydrogen-rock reaction and possible methane production. We also measured H2/brine and CH4/brine interfacial tensions (IFT), as well as the contact angles of H2/brine/shale and CH4/brine/shale systems at 75 °C and varying pressure (500–1500 psi) to understand the shale-fluid interaction at subsurface conditions. Results indicate some reaction of H2 with the shale after 80 days. No hydrogen sulfide was detected from gas chromatography analysis at the end of the experiment, but traces of methane (0.018 %) were detected. The reaction between hydrogen and organic matter of the shale yielded only a little methane under the conditions investigated in this research, possibly because the experimental temperature and reaction time was insufficient for copious methane generation. Furthermore, contact angle values of CH4/brine were found to be higher than of H2/brine. This means that under geo-storage conditions, the surface becomes fully CH4-wet condition (131o-149o) but remains only intermediate-wet in the presence of the H2/brine system (94o -106o) with increasing pressure, confirming that the interaction of methane with the shale surface is higher than hydrogen-shale surface interaction at similar conditions. The opposite trend was observed for IFT values. The hydrogen/brine IFT was 69.4 mN/m at 500 psi but decreased to 67.9 mN/m at 1500 psi. Likewise, the methane/brine IFT decreased from 69.7 mN/m to 58.3 mN/m with increasing pressure from 500 to 1500 psi. The findings of this study contribute to a better understanding of the adsorption trapping potential of organic-rich source rocks.

The sustainability of green hydrogen: An uncertain proposition

Green hydrogen is increasingly considered a vital element for the long-term decarbonization of the global energy system. For regions with scarce land resources, this means importing significant volumes of green hydrogen from regions with abundance of renewable energy. In producing countries, this raises significant sustainability questions related to production and export. To assess these sustainability-related opportunities and challenges, the authors first present a review of renewable energy deployment in the electricity sector, and then extend it to the foreseeable opportunities and risks of green hydrogen production in exporting countries. The paper finds that questions of freshwater and land availability are critical from an environmental and a socio-economic point of view, and that the development of international standards for the governance of hydrogen-related projects will be crucial. These should also address potential conflicts between the deployment of renewable energy for the decarbonization of local power grids, and the export of green hydrogen.

Europe proposes green hydrogen definition

The European Commission’s proposed definition and rules for green hydrogen have been met with criticism from both industry and environmentalists. The aim of the rules is to encourage developers to build green hydrogen capacity while ensuring that only facilities powered by renewable electricity can count toward EU sustainability targets. The proposal defines green hydrogen as coming from water electrolysis powered by newly built equipment for generating renewable electricity. An electrolysis plant with an on-site solar farm would count, but a grid-powered plant would have to buy renewable electricity from a nearby source built no more than 36 months before the hydrogen plant came on line. It would also need to match volumes of hydrogen with corresponding renewable wattage on an hour-by-hour basis. The industry group Hydrogen Europe welcomed the proposal but criticized the requirement that the renewable electricity be generated nearby at the same time as the hydrogen. “These strict

Cobalt ferrite nanoparticles anchored on reduced graphene oxide nanoribbons (0D/1D CoFe2O4/rGONRs) as an efficient catalyst for hydrogen generation via NaBH4 hydrolysis

For better performance of nanoparticles as the heterogeneous catalyst, various materials with a large surface area have been introduced as the substrate. Herein, CoFe2O4 nanoparticles were anchored on carbon nanotubes (CoFe2O4/CNTs) and graphene nanoribbons (CoFe2O4/GONRs) to investigate the influence of substrate in the catalytic performance. These nanocomposites were evaluated in a NaBH4 hydrolysis reaction to produce hydrogen. The results showed that the highest hydrogen volume occurs in the presence of CoFe2O4/GONRs nanocatalyst. Abundant oxygen-based functional groups at the edges of GONRs offered excellent sites for CoFe2O4 nanoparticles and improved catalytic performance. Under optimum conditions (2.0 wt% of NaBH4, 15 mg of catalyst, 2.0 wt% of NaOH), the hydrogen generation rate was found to be 3.7 L g-1min−1 at 35 °C. The activation energy was calculated using the Arrhenius method, equivalent to 31.4 kJ mol−1. Therefore, CoFe2O4/GONRs catalyst can be a novel and efficient candidate for hydrogen production as a clean fuel.

Design and thermodynamic analysis of solid oxide fuel cells–internal combustion engine combined cycle system based on Two-Stage waste heat preheating and EGR

The integrated solid oxide fuel cell (SOFC)-internal combustion engine (ICE) hybrid system has attracted more and more attention due to its advantages of high efficiency and good response ability. Combined with waste heat recovery (WHR) strategy, the system energy conversion efficiency can be further improved. In this study, a new integrated hybrid power system consisting of SOFC and pilot diesel micro-ignition natural gas engine, with WHR strategy was designed and analyzed. Firstly, the mathematical modeling of each component was established and compared with the experimental results to ensure the reliability of the simulation results. Moreover, the effects of key operating parameters and natural gas mixing with an appropriate amount of hydrogen on improving system efficiency and exergy efficiency were also explored. The results showed that the efficiency of the combined system was higher than each component and improved with the increase in the power distribution ratio of the SOFC and ICE, while descended with the decrease of fuel utilization of the SOFC. Anode exhaust of SOFC had a similar effect on the engine as exhaust gas recirculation, which can significantly reduce NOx emissions. In addition, when the SOFC and ICE had equal power distribution with fuel utilization of 0.7, with adding a 25% hydrogen volume ratio, the exergy efficiency and thermal efficiency of the system increased by 6.01% and 5.8% respectively.

Numerical investigation on combustion regulation for a stoichiometric heavy-duty natural gas engine with hydrogen addition considering knock limitation

Aiming to further improve the thermal efficiency and reduce NOx emissions in the stoichiometric hydrogen-enriched natural gas (NG) engine, a detailed 3-D simulation model of stoichiometric operation heavy-duty NG engine is built based on the actual boundary conditions from high load bench test. The superimposed methods for knock regulation, combustion and emission control, including Miller valve timing, hydrogen volume fraction and EGR rate were proposed and investigated comprehensively. It reveals that the typically bimodal characteristic of heat release rate (HRR) curve is caused by knock, which seriously restricts the performance improvement of stoichiometric NG engine under high load condition. To predict and control the occurrence of the second peak of HHR accurately, a new parameter BI is defined. Moreover, the Miller timing with 20°CA of the intake valve late closing shows better combustion performance within the knock limit, accompanied by a slight increase in NOx emissions. Additionally, the 5% hydrogen blend, coupled with the Miller cycle, can further enhance the indicated thermal efficiency (ITE) of the NG engine due to the stronger effects on acceleration of laminar flame propagation velocity than the promotion of end-gas auto-ignition. Besides, the great potential of EGR rate for balancing NOx and ITE is also confirmed in the heavy-duty hydrogen-enriched NG engine adopting Miller cycle. Compared to the original indexes, combing with the regulation strategies of intake valve late closing (20°CA), hydrogen addition (5%) and EGR (17%) are proved to increase the indicated thermal efficiency by 1.89% and reduce NOx emissions by 11.47% within the knock limit.