Hydrogen Blends Research Articles

Evaluation of the environmental impact of HCNG light-duty vehicles in the 2020–2050 transition towards the hydrogen economy

As the world intensifies its efforts to reduce the adverse effects of global warming, the shift towards a fully developed hydrogen-based economy is emerging as a core strategy. This transition involves the strategic blending of hydrogen with conventional fossil fuels such as natural gas (HCNG), allowing for adaptation to hydrogen availability. Nevertheless, the environmental impact of HCNG vehicles in realistic scenarios with variable hydrogen content remains unexplored. This study focuses on evaluating the global warming impact of the transition of light-duty passenger cars from CNG to H2 vehicles using HCNG blends from 2020 to 2050 and different realistic scenarios. The results in the present study were obtained through a combination of an experimental testing campaign that allowed obtaining how the performance and emissions of HCNG vehicles change with the H2 content and a life cycle assessment methodology. Based on the findings, the scenario in which hydrogen was mostly produced from SMR-dominant, was found to have the potential to reach and outperform the zero-emission concept due to the utilization of biogas. From the results of this study, the recommended H2 content in HCNG blends that offers low environmental impact while avoiding the overdemand of hydrogen in the short term for the 2020–2030 decade is 25% H2 content, increasing to 50% by 2030, and to 75%–100% during the 2040–2050 decade, thus reaching the transition towards pure-H2 technology that minimizes environmental impact.

A numerical study on the mixing characteristics and mechanisms of (H2+CH4)/air in a miniature combustor

In the present study, the influences of three operating parameters on the mixing performance of H2/CH4 blends and air in a miniature combustor with a rectangular cross section were numerically investigated. The results show that: (1) The mixing process of H2 and air is faster than CH4 and air. (2) The mixing process of H2 and air is diffusion-dominated under low velocities, while convection-dominated under medium and high velocities; However, the mixing of CH4 and air is diffusion-dominated under both low and high average velocities, but dominated by convection under medium velocities. (3) An increase in the nominal equivalence ratio creates a larger fuel concentration gradient perpendicular to the mainstream, which leads to an increase in the diffusion rate. (4) A larger hydrogen blending ratio intensifies the fuel stratification at the combustor entrance, which deteriorates the mixing performance. (5) An empirical correlation is established between the mixing performance evaluation criterion and the three parameters. The nominal equivalence ratio is the most significant factor to the mixing performance.

Experimental investigation of various burner heads in residential gas stoves tested with hydrogen and natural gas blends

The current study is designed to investigate the effect of five different burner head geometries of gas stoves. The amounts of heat required for boiling 380 grams of water in a pot for a stove for these several burner heads are measured. The flow rates are set to be 3 L/min and 6 L/min for experimental tests. These experimental results show that the burner head with three lateral sets of holes and two circular sets of holes at the top gives the minimum heating time when burning natural gas alone. Once the hydrogen-natural gas mixture is used, the burner head with one lateral and three top circular sets of holes shows the best performance among others regarding heating time. The effect of the flow rate increase is also investigated. Once the flow rate doubles, the burner head with three lateral sets of holes offers the best performance. Based on the findings of the experiments, it can be said that burner heads with lateral sets of holes operate better than other geometries. When natural gas is utilized as fuel, it is observed that the burner head with three lateral sets of holes and two circular sets of holes at the top provided a 12% reduction in heating time compared to the conventional burner head. For the natural gas and hydrogen blends, the conventional burner head achieves the best in terms of heating time.

Performance of biogas blended with hydrogen in a commercial self-aspirating burner

A natural gas and carbon dioxide fuel mixture was enriched by hydrogen to experimentally measure the performance of a hydrogen and surrogate biogas fuel. The performance of various biogas qualities and hydrogen blend ratios was investigated for use in a commercial self-aspirating burner by quantifying the impact on primary air entrainment, blow-off and flashback limits, NOx emissions, radiant heat transfer and flame appearance. The results showed operating limits of a biogas or hydrogen flame alone could be extended by blending one with the other and by increasing fuel injector size (lowering primary air entrainment), with the latter being more effective. The collateral impact of carbon dioxide and hydrogen addition on radiant heat transfer could be mitigated by increasing injector size, with the carbon dioxide content in biogas maintaining NOx levels at or below the level of natural gas. Overall, there appears to be merit for hydrogen and biogas to operate as a mutually beneficial fuel in a commercial self-aspirating burner design.

Research progress on corrosion and hydrogen embrittlement in hydrogen–natural gas pipeline transportation

Hydrogen, clean, efficient and zero-carbon, is seen as a most promising energy source. The use of existing gas pipelines for hydrogen–natural gas transportation is considered to be an effective way to achieve long-distance, large-scale, efficient, and economical hydrogen transportation. However, the pipelines for hydrogen–natural gas transportation contain lots of impurities (e.g., CH4, high-pressure H2, H2S and CO2) and free water, which will inevitably lead to corrosion and hydrogen embrittlement. This paper presents a systematic review of research and an outlook for corrosion and hydrogen embrittlement in hydrogen–natural gas pipeline transportation. The results show that gas-phase hydrogen charging is suitable for hydrogen–natural gas transportation, but this technique lacks technical standards. By contrast, the liquid-phase hydrogen charging technique is more mature but has large deviation from the engineering reality. In the hydrogen–natural gas transportation pipelines, corrosion and hydrogen embrittlement are synergetic and competitive, but the failure mechanism and change law when corrosion and hydrogen embrittlement coexist remain unclear, which need to be further clarified by experiments. The failure mechanism is believed to be mainly sensitive to three key factors, i.e., the H2S/CO2 partial pressure ratio, the hydrogen blending ratio, and material strength. The increase of the three factors will make the pipeline materials more corrosive and more sensitive to hydrogen embrittlement. The research findings can be used as a reference for research and development of long-distance hydrogen–natural gas transportation technology and will drive the high-quality development of the hydrogen–natural gas blending industry.

Effects of hydrogen addition on the propagation and autoignition of methane/oxygen/inert mixtures under engine-relevant conditions

The confined spherical expanding flame method was used to measure laminar flame speeds and ignition delay times of blends of methane and hydrogen at engine-relevant conditions. Laminar flame speeds were measured for hydrogen addition to methane of up to 40 % on a molar basis, for pressures ranging from 8 to 30 atm, and for unburned mixture temperatures ranging from 420 to 530 K. It was found that the laminar flame speed increases with the hydrogen addition, as expected, and that the trend of the data is consistent with predictions resulting from using recently developed kinetic models. For properly chosen conditions, autoignition of the end gas was induced during the compression stage of the outward flame propagation, and ignition delay times were determined using the rapid changes in the pressure-time derivatives. The autoignition experiments were carried out for blends of methane, n-pentane, and hydrogen. The use of n-pentane was essential in order to achieve autoignition within the time scales available in the existing spherical facility. In the presence of n-pentane, a two-stage ignition behavior was observed, and the addition of hydrogen was found to reduce the ignition delay times. All data were modeled, and insight was provided into the mechanisms controlling flame propagation and the two stages of ignition. These results are expected to be of direct relevance to ongoing efforts in hydrogen utilization toward the decarbonization of the transportation sector.

An Optimal Dispatch Method of Integrated Electricity and Gas Systems Incorporating Hydrogen Injection Flexibility

Hydrogen enriched compressed natural gas provides a promising way of decarbonizing integrated electricity and gas systems. Considering the flexible characteristics of hydrogen enriched compressed natural gas, this paper proposes an optimal dispatch method for integrated electricity and gas systems incorporating hydrogen injection. A hydrogen blending transmission model is developed for hydrogen enriched compressed natural gas. The dynamic characteristics and the line pack are captured considering the impacts of hydrogen injection on pipeline transmission and line pack parameters. From the overall system operation aspect, a detailed energy flow model of hydrogen enriched compressed natural gas involving pipeline, compressor, and nodal gas flow balance is established incorporating the coupling relationship with hydrogen volume fraction. This model allows for the consideration of the impacts of time-varying hydrogen volume fractions on the optimal dispatch of systems. A novel estimation model is proposed to effectively determine the hydrogen volume fraction, which considers the impacts of line pack on hydrogen enriched compressed natural gas. Based on the proposed energy flow model, the line pack and the flexible adjustment of hydrogen volume fraction are aggregated into the flexible characteristics of hydrogen enriched compressed natural gas. A low-carbon dispatch method incorporating these flexible characteristics is developed to decarbonize integrated electricity and gas systems. Case studies on two test systems are presented to validate the effectiveness and applicability of the proposed model and method. The simulation results demonstrate that the accommodation levels of renewable energy and green hydrogen injection can be largely enhanced.

Numerical simulation of the transport and thermodynamic properties of imported natural gas injected with hydrogen in the manifold

Blending hydrogen with natural gas (NG) is an efficient method for transporting hydrogen on a large scale at a low cost. The manifold at the NG initial station is an important piece of equipment that enables the blending of hydrogen with NG. However, there are differences in the components and component contents of imported NG from different countries. The components of hydrogen-blended NG can affect the safety and efficiency of transportation through pipeline systems. Therefore, numerical simulations were performed to investigate the blending process and changes in the thermodynamic properties of four imported NGs and hydrogen in the manifold. The higher the heavy hydrocarbon content in the imported NG, the longer the distance required for the gas to mix uniformly with hydrogen in the pipeline. Hydrogen blending reduces the temperature and density of NG. The gas composition is the main factor affecting the molar calorific value of a gas mixture, and hydrogen blending reduces the molar calorific value of NG. The larger the content of high-molar calorific components in the imported NG, the higher the molar calorific value of the gas after hydrogen blending. Increasing both the temperature and hydrogen mixing ratio reduces the Joule-Thomson coefficient of the hydrogen-blended NG. The results of this study provide technical references for the transport of hydrogen-blended NG.

Investigation of the control strategy for hydrogen addition in all operating conditions of a high compression ratio liquid methane heavy-duty engine

The hydrogen addition to liquid methane gas (LMG) engines based on the rational control strategy is considered to be a promising approach to improve the performance of LMG engines. However, the current studies are limited to a few operating points. To comprehensively develop a control strategy of hydrogen addition for high compression ratio LMG engines, the effects of hydrogen addition on the emissions, combustion, and performance of an LMG engine are experimentally investigated under all operating conditions in this study. Furthermore, to achieve the optimal performance of the hydrogen-LMG engine with the optimal hydrogen blending, the coupled simulation model of MATLAB/Simulink and GT-Power is established based on the test bench, and the multiple operating parameters of the calibrated numerical model are optimized by using genetic algorithm. The results show that the maximum increases in the brake thermal efficiency with increasing hydrogen energy share (HES) are 1.6, 0.9 and 0.6 percentage points under low, medium and high loads, respectively. Correspondingly, the maximum reduction in EBSFC under low, medium and high loads is 6.5 %, 2.2 % and 1.4 %, respectively. The ignition delay is reduced and the combustion is promoted with the increase in HES. As a result, the cylinder pressure and HRR rise faster and reach a higher peak earlier. In addition, the 50 % combustion location is advanced and the 10–90 % combustion duration is shortened. In terms of emissions, the increasing HES promotes the NOx emissions and reduces the HC emissions. Especially at medium and high loads, the NOx emissions rise sharply with increasing HES. It is desirable that HES should not exceed 15 %, 4 % and 2 % at low, medium and high loads, respectively. In addition, by co-optimizing the intake valve opening timing, exhaust valve opening timing and the spark angle, the BSFC of the hydrogen-LMG engine with the optimal HES under 1200 rpm and BMEP of 6 bar is still improved by 2.2 %. This study provides new insights to further explore the energy-saving potential of hydrogen-LMG engines.

Ramping up the hydrogen sector: An energy system modeling framework

With the transition towards a decarbonized society, energy system integration is becoming ever more essential. In this transition, the energy vector hydrogen is expected to play a key role as it can be produced from (renewable) power and natural gas with carbon capture and storage and utilized in a plethora of applications and processes across sectors. Despite global hydrogen demand reaching 94 million tonnes in 2021, still less than 0.7% of it is supplied by low-emission hydrogen. Moreover, to date hydrogen production is mostly located in close proximity to where it is used. In order to link future production and demand sites, it is planned to re-purpose existing natural gas and expand dedicated hydrogen pipelines. During the early stages of ramping up the hydrogen sector (2020s and early 2030s), however, blending natural gas with hydrogen for joint pipeline transmission has been suggested. Against this background, this paper studies hydrogen blending from a modeling perspective, both in terms of the implications of considering (or omitting) technical modeling details and in terms of the potential impact on the ramp-up of the hydrogen sector. To this end, we present a highly modular and flexible integrated sector-coupled energy system optimization model of the power, natural gas, and hydrogen sectors with a novel gas flow formulation for modeling blending in the context of steady-state gas flows. A stylized case study illustrates that hydrogen blending has the potential to initiate and to facilitate the ramp-up of the hydrogen sector under certain assumptions, while omitting the technical realities of gas flows – particularly in the context of blending – can result in suboptimal expansion planning not only in the hydrogen, but also in the power sector, as well as in an operationally infeasible system.

Research Progress and Prospects on Hydrogen Damage in Welds of Hydrogen-Blended Natural Gas Pipelines

Hydrogen energy represents a crucial pathway towards achieving carbon neutrality and is a pivotal facet of future strategic emerging industries. The safe and efficient transportation of hydrogen is a key link in the entire chain development of the hydrogen energy industry’s “production, storage, and transportation”. Mixing hydrogen into natural gas pipelines for transportation is the potential best way to achieve large-scale, long-distance, safe, and efficient hydrogen transportation. Welds are identified as the vulnerable points in natural gas pipelines, and compatibility between hydrogen-doped natural gas and existing pipeline welds is a critical technical challenge that affects the global-scale transportation of hydrogen energy. Therefore, this article systematically discusses the construction and weld characteristics of hydrogen-doped natural gas pipelines, the research status of hydrogen damage mechanism, and mechanical property strengthening methods of hydrogen-doped natural gas pipeline welds, and points out the future development direction of hydrogen damage mechanism research in hydrogen-doped natural gas pipeline welds. The research results show that: ① Currently, there is a need for comprehensive research on the degradation of mechanical properties in welds made from typical pipe materials on a global scale. It is imperative to systematically elucidate the mechanism of mechanical property degradation due to conventional and hydrogen-induced damage in welds of high-pressure hydrogen-doped natural gas pipelines worldwide. ② The deterioration of mechanical properties in welds of hydrogen-doped natural gas pipelines is influenced by various components, including hydrogen, carbon dioxide, and nitrogen. It is necessary to reveal the mechanism of mechanical property deterioration of pipeline welds under the joint participation of multiple damage mechanisms under multi-component gas conditions. ③ Establishing a fundamental database of mechanical properties for typical pipeline steel materials under hydrogen-doped natural gas conditions globally is imperative, to form a method for strengthening the mechanical properties of typical high-pressure hydrogen-doped natural gas pipeline welds. ④ It is essential to promptly develop relevant standards for hydrogen blending transportation, welding technology, as well as weld evaluation, testing, and repair procedures for natural gas pipelines.

Effect of hydrogen-enriched natural gas on flue gas waste heat recovery potential and condensing heat exchanger performance

Hydrogen-enriched natural gas (HENG) is one of the significant ways to store, transport, and utilize hydrogen energy. This paper presents the characteristics of HENG and flue gas, energy saving, carbon reduction, and condensate recovery potential of flue gas waste heat. Based on the theoretical and experimental study of the existing flue gas condensing heat exchanger (FGCHE) added at the rail of gas-fired boiler, the performance of the FGCHE under different hydrogen blending ratios is studied. The results show that augmenting the hydrogen blending ratio decreases the volume heating value of HENG, and CO2 content of flue gas. Meanwhile, the mass heating value of the HENG, the water vapor content, and dew point temperature of flue gas increase as the hydrogen blending ratio increases. The flue gas waste heat recovery utilization ratio and energy-saving efficiency of the FGCHE can be promoted. Moreover, the heat transfer capacity of the FGCHE using HENG is enhanced, while the flue gas flow pressure drop is reduced. Compared with the FGCHE used in pure natural gas systems, the all-hydrogen system increases the flue gas waste heat recovery amount by 62.4–120.4 %, reduces the flue gas flow pressure drop by 33.9 %, and reduces the carbon emission by 100 %.

Effects of hydrogen blending and exhaust gas recirculation on NO[formula omitted] emissions in laminar and turbulent [formula omitted] flames at 25 bar

In this work, the effect of Exhaust Gas Recirculation (EGR) on NOx emissions in a CH4/H2/air combustion at 25 bar, at an equivalence ratio Φ = 0.7, is analyzed in laminar and turbulent partially premixed flames. Numerical simulations of twenty premixed and partially premixed counterflow flames with H2 ranging from 0 to 100%, with and without EGR, are carried out. Analysis of NO formation mechanisms shows that the thermal path is the main responsible for the NOx production in each flame, with a contribution of nearly 80%. In laminar flames an increase of H2 leads to an increase in NOx emissions. The addition of the exhaust gas decreases the flame temperature and therefore NOx: each laminar flame shows a NOx reduction of about 60% with the presence of exhaust gas. Four turbulent slot jet flames with a CH4/H2/Air/EGR premixed central core and Air/EGR as coflow are studied in a two-dimensional framework using the Reynolds Averaged Navier–Stokes (RANS) approach and the Large Eddy Simulation (LES) methodology, to take into account some flame dynamics, despite the 2D context. Accurate molecular transport properties are considered and, a reduced specifically designed chemical mechanism for methane/hydrogen-air combustion at Φ=0.7, consisting of 48 transported species and 465 elementary reactions is adopted. The four turbulent flames were simulated with 0 and 50% hydrogen concentration, with and without EGR. The presence of hydrogen reduces CO2 emissions, but at the same time increases NO concentration, the thermal path being the main NO formation mechanism. The use of exhaust gas recirculation leads to NO reduction as in laminar flames. The results obtained in this work show that at high pressure, the hydrogen enrichment of natural gas in the EGR mode leads to lower NOx as well as CO2 emissions.

Analytical Evaluation of Loss Mechanism Effects on PDE Performance with Variation of Refilling Beta Parameters

The present research work is to investigate, how the pulse detonation engine's (PDE) performance is affected by thermodynamic detonation factors. This analysis deals with the evaluation of PDE by using pure fuels like hydrogen, propane, and butane and a blend of hydrogen (50%) + propane (50%), butane (50%) + hydrogen (50%) and propane (50%) + butane (50%). The performance prediction model method is based on flow paths. Performance loss mechanisms, like the refilling process are recognized and enumerated. Inside flow damage, which mostly results from shock waves inside the PDE combustion tube, is a major factor in the PDE's performance degradation. The novelty of the present analysis is to observe that the Hydrogen fuel displays the maximum specific impulse of 7280 s with a detonation velocity of 2321 m/s at the value of beta 0.17. whereas, the lowest specific impulse is produced by butane with the same beta value.

Insights into the role of CO in inhibiting hydrogen embrittlement of X80 steel weld at different hydrogen blending ratios

In this study, slow strain rate tension tests were conducted on an X80 steel weld in 12 MPa mixed gases with 2 %–75 % H2 ([H2]) and 0 %–0.75 % CO ([CO]). The influence mechanism of CO on inhibiting hydrogen embrittlement (HE) was explored with the aid of the first-principles method and hydrogen permeation tests. The results show that the HE index first decreases rapidly with the increase of [CO] or [CO]/[H2], and then tends to stabilize. CO can restore the hydrogen induced plastic loss to a certain value, and the recovery degree decreases with the increase of [H2]. CO preferentially occupies the hydrogen adsorption site when co-existing with H2, and can reduce but not completely inhibit hydrogen permeation, this is the essential reason why the change of [CO] affects HE susceptibility.

Evaluation of Nox Emissions Associated to Non-Premixed Combustion of H2/Natural Gas Blends in a 40 MW Heavy-Duty Gas Turbine

Abstract The tightening in the international regulations is leading the energy production sector toward the usage of hydrogen, which is a zero-carbon energy carrier. In the field of gas turbine lifetime extension, a nonpremixed approach including hydrogen blending with conventional fuels is the most promising. However, high-temperature spots might occur, thus increasing thermo-mechanical stresses and NOx emissions. Therefore, a reliable evaluation of the impact of hydrogen blends in combustors characterized by nonpremixed flames is necessary. In the present work, a 40 MW heavy-duty multican combustor belonging to EthosEnergy is investigated by means of steady, reactive simulations by using the ANSYS® FLUENT® solver. The combustor geometry is simplified by removing the casing volume, being the flow split among the holes already available. Such simplification allows for paying major attention to the chemical kinetics thanks to the use of the extended reaction mechanism for natural gas developed by National University of Ireland Galway. Simulations include the assessment of the natural gas base load configuration together with hydrogen blends up to 50% in volume, while maintaining unaltered the turbine inlet temperature (TIT). The obtained data provide some retrofitting guidelines in the field of hydrogen usage in nonpremixed combustion and prove for a modified temperature field in the combustor core and close to the basket. A linear increase in NOx emission is also associated with hydrogen addition, thus suggesting the need for NOx abatement technologies (e.g., water injection).

Capacity allocation method of hydrogen-blending natural gas pipeline network based on bilevel optimization

Blending hydrogen into the natural gas pipeline network is an efficient approach for storing and delivering renewable energy. However, the variation in gas quality and the diversity of delivery paths can lead to difficulties in pipeline operation management. In this paper, we propose a bilevel optimization model to understand the influence of hydrogen blending on pipeline capacity allocation and gas transmission tariffs. The lower-level model optimizes the best capacity booking of each shipper, and the upper-level model optimizes the best capacity allocation of the transmission system operator. Detailed transmission paths and gas calorific values at each delivery point are taken into account to calculate the actual gas transmission tariffs. The proposed model is solved by the alternating direction multiplier method and validated by a real-world pipeline network. Results show that: (1) the proposed method can facilitate shippers to meet the energy demand under different hydrogen blending cases, (2) a fair-cost sharing is achieved among all parties, (3) when the hydrogen blending ratio reaches 5 %, the pipeline capacity can be optimally utilized to achieve the maximum pipeline capacity allocation. This approach can guide efficient gas pipeline capacity allocation and facilitate the establishment of trading platforms.

Effects of hydrogen blending ratio on combustion and emission characteristics of an ammonia/hydrogen compound injection engine under different excess air coefficients

Currently, hydrogen and ammonia are the best green, zero-carbon energies worldwide. Applying ammonia and hydrogen to internal combustion engines is a top priority for achieving the dual-carbon goal for the automotive industry. However, both ammonia and hydrogen have disadvantages that make them unsuitable for use as fuels on their own. Hydrogen internal combustion engines can suffer from abnormal burning, such as premature ignition, backfiring, and detonation. At the same time, the difficulty of hydrogen storage, transportation, and refilling can also lead to the problem of high cost of use. Ammonia suffers from high ignition energy, poor flame-spreading speed, and inadequate burning stabilization. When used alone, it causes incomplete combustion of large amounts of ammonia. Therefore, our group uses the spray pattern of “hydrogen direct injection (HDI) plus ammonia port injection (API). ” The influence of hydrogen blending ratio (HBR) on the combustion and emission characteristics of an ammonia/hydrogen compound injection engine with various excess air coefficients (λ) is investigated. The blending ratios of hydrogen are 6.1 %, 16.8 %, 27.3 %, 37.7 %, 47.8 %, and 57.7 %, respectively. The experimental data suggests that the indicated mean effective pressure (IMEP) shows an incremental trend as the hydrogen blending ratio grows. Not only CA0-10 but also CA10-90 have been reduced. The whole combustion process is shortened. The temperature and pressure rise. When the ratio of hydrogen blending is higher than 27.3 %, the enhancement of the burning characteristics by hydrogen is not apparent. NOX emissions rise with the ratio of hydrogen blending. NH3 emissions tend to drop as the blending ratio of hydrogen rises. Combining the emission and combustion characteristics, the general engine performance is better when the λ is 1.2 and the ratio of hydrogen blending is 27.3 %.

Hydrogen Combustion: Features and Barriers to Its Exploitation in the Energy Transition

The aim of this article is to review hydrogen combustion applications within the energy transition framework. Hydrogen blends are also included, from the well-known hydrogen enriched natural gas (HENG) to the hydrogen and ammonia blends whose chemical kinetics is still not clearly defined. Hydrogen and hydrogen blends combustion characteristics will be firstly summarized in terms of standard properties like the laminar flame speed and the adiabatic flame temperature, but also evidencing the critical role of hydrogen preferential diffusion in burning rate enhancement and the drastic reduction in radiative emission with respect to natural gas flames. Then, combustion applications in both thermo-electric power generation (based on internal combustion engines, i.e., gas turbines and piston engines) and hard-to-abate industry (requiring high-temperature kilns and furnaces) sectors will be considered, highlighting the main issues due to hydrogen addition related to safety, pollutant emissions, and potentially negative effects on industrial products (e.g., glass, cement and ceramic).

Centrifugal compressor performance prediction and dynamic simulation of natural gas hydrogen blended

It is great significant to explore the changes of compressor performance for hydrogen transportation. We found that a Gray-RBF neural network prediction model improved prediction accuracy. The prediction error of the model is 2.34 % by data verification. It was found that the hydrogen blending ratio was increased from 0 % to 30 %, the pipeline transmission power was reduced by 9.3 %. Simultaneously injecting hydrogen to natural gas causes the performance curve of the compressor to shift downwards. The pressure ratio decreases by 18.9 % and shaft power decreases by 28.6 % when the hydrogen blending ratio increases from 0 % to 30 %. The injection of hydrogen to natural gas causes the surge range of the compressor to increase, so the stable range to narrow. In general, this research may provide reference and guidance for the transportation research of hydrogen blended natural gas and compressor operation about gas industry.