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The direct conversion of methane to methanol has attracted increasing interest due to abundant and low-cost natural gas resources. Herein, by anchoring Cr-oxo/-oxyhydroxides on UiO-66 metal–organic frameworks, we demonstrate that reactive anionic oxyl radicals can be formed by controlling the coordination environment based on the results of density functional theory calculations. The anionic oxyl radicals produced at the completely oxidized CrVI site acted as the active species for facile methane activation. The thermodynamically stable CrVI-oxo/-oxyhydroxides with the anionic oxyl radicals catalyze the activation of the methane C–H bond through a homolytic mechanism. An analysis of the results showed that the catalytic performance of the active oxyl species correlates with the reaction energy of methane activation and H adsorption energies. Following methanol formation, N2O can regenerate the active sites on the most stable CrVI oxyhydroxides, i.e., the Cr(O)4Hf species. The present study demonstrated that the anionic oxyl radicals formed on the anchored CrVI oxyhydroxides by tuning the coordination environment enabled facile methane activation and facilitated methanol production. [ABSTRACT FROM AUTHOR]

In this study, we used a high-throughput computational screening approach to examine the potential of metal–organic frameworks (MOFs) for capturing propane (C3H8) from different gas mixtures. We focused on Quantum MOF (QMOF) database composed of both synthesized and hypothetical MOFs and performed Grand Canonical Monte Carlo (GCMC) simulations to compute C3H8/N2/O2/Ar and C3H8/C2H6/CH4 mixture adsorption properties of MOFs. The separation of C3H8 from air mixture and the simultaneous separation of C3H8 and C2H6 from CH4 were studied for six different adsorption-based processes at various temperatures and pressures, including vacuum-swing adsorption (VSA), pressure-swing adsorption (PSA), vacuum–temperature swing adsorption (VTSA), and pressure-temperature swing adsorption (PTSA). The results of molecular simulations were used to evaluate the MOF adsorbents and the type of separation processes based on selectivity, working capacity, adsorbent performance score, and regenerability. Our results showed that VTSA is the most effective process since many MOFs offer high regenerability (>90%) combined with high C3H8 selectivity (>7 × 103) and high C2H6 + C3H8 selectivity (>100) for C3H8 capture from air and natural gas mixtures, respectively. Analysis of the top MOFs revealed that materials with narrow pores (<10 Å) and low porosities (<0.7), having aromatic ring linkers, alumina or zinc metal nodes, typically exhibit a superior C3H8 separation performance. The top MOFs were shown to outperform commercial zeolite, MFI for C3H8 capture from air, and several well-known MOFs for C3H8 capture from natural gas stream. These results will direct the experimental efforts to the most efficient C3H8 capture processes by providing key molecular insights into selecting the most useful adsorbents. [ABSTRACT FROM AUTHOR]

Indoor sources of air pollution worsen indoor and outdoor air quality. Thus, identifying and reducing indoor pollutant sources would decrease both indoor and outdoor air pollution, benefit public health, and help address the climate crisis. As outdoor sources come under regulatory control, unregulated indoor sources become a rising percentage of the problem. This American Thoracic Society workshop was convened in 2022 to evaluate this increasing proportion of indoor contributions to outdoor air quality. The workshop was conducted by physicians and scientists, including atmospheric and aerosol scientists, environmental engineers, toxicologists, epidemiologists, regulatory policy experts, and pediatric and adult pulmonologists. Presentations and discussion sessions were centered on 1) the generation and migration of pollutants from indoors to outdoors, 2) the sources and circumstances representing the greatest threat, and 3) effective remedies to reduce the health burden of indoor sources of air pollution. The scope of the workshop was residential and commercial sources of indoor air pollution in the United States. Topics included wood burning, natural gas, cooking, evaporative volatile organic compounds, source apportionment, and regulatory policy. The workshop concluded that indoor sources of air pollution are significant contributors to outdoor air quality and that source control and filtration are the most effective measures to reduce indoor contributions to outdoor air. Interventions should prioritize environmental justice: Households of lower socioeconomic status have higher concentrations of indoor air pollutants from both indoor and outdoor sources. We identify research priorities, potential health benefits, and mitigation actions to consider (e.g., switching from natural gas to electric stoves and transitioning to scent-free consumer products). The workshop committee emphasizes the benefits of combustion-free homes and businesses and recommends economic, legislative, and education strategies aimed at achieving this goal.

Gas explosions mostly occur in turbulent environments in practical situations. Meanwhile, the current research on the explosion characteristics of hydrogen-doped natural gas is mostly methane/hydrogen mixed fuel, ignoring the influence of other components of natural gas on the explosion characteristics of the actual situation. Therefore, the effects of different jet intensities (P jet), hydrogen-doping ratios (X H2) and equivalence ratios (φ) on the explosion characteristics of multi-component natural gas/hydrogen mixed fuel are experimentally investigated in cylindrical tanks of 30 L. Additionally, it extensively explored the dual influence of jet disturbance and gas inerting effect on the flame propagation characteristics of multi-component natural gas/hydrogen mixed fuel. With the increase of P jet , both P max and (d p/ d t) max initially increase and then decrease, while τ continuously decreases. When P jet = 0.4 MPa, the promotion effect on P max and (d p/ d t) max is most significant. The lifting of X H2 leads to a gradual increase in P max and decreasing τ. (d p/ d t) max exhibits a trend of initially increasing and then decreasing with the elevation of X H2 , reaching its maximum at X H2 = 40%. The introduction of jet flow significantly reduces the promotion or inhibition effect on explosions of high hydrogen blending ratio mixtures. Furthermore, the introduction of jet flow is more effective in promoting the explosive performance of multi-component natural gas/hydrogen mixed fuel with high equivalence ratios and low hydrogen doping ratios under rich fuel conditions. This study can provide a key reference for the explosion hazard assessment during the practical application of natural gas/hydrogen mixed fuel. • Hydrogen-doped natural gas is used in explosion experiments collected in real environments. • A gas jet disturbance experimental platform has been established. • The flame propagation characteristics under turbulent conditions have been summarized. • The promotion effect on the explosion is most significant when the jet intensity reaches 0.4 MPa. [ABSTRACT FROM AUTHOR]

Methane pyrolysis is emerging as an attractive clean hydrogen production method. As its commercialization proceeds, the pyrolysis of natural gas (NG) becomes pertinent. In this work, the decomposition of pure methane and a realistic NG mixture are compared experimentally and numerically. Methane and NG pyrolysis are performed between 600 and 1200 °C over a fluidized bed of carbon particles heated by microwaves. Experimentally, no conclusive difference is observed in methane conversion between methane and NG pyrolysis. Numerically, the methane conversion rate is 8.5% higher for NG at 950 °C. The difference diminishes past 950 °C, becoming 0 past 1050 °C. The simulations showed that the enhanced methane decomposition in NG pyrolysis is due to an attack on methane by radicals generated during ethane and propane decomposition. The CO 2 in our NG mixture decomposes into CO. This work validates the longstanding use of methane pyrolysis as a surrogate for NG pyrolysis. • Experimentally, no conclusive difference between NG and pure CH 4 pyrolysis. • Numerically, NG pyrolysis had at most 8.5% higher methane conversion. • Radicals from ethane decomposition attacked methane and increased methane conversion. • Inlet C 2 H 6 > 10 vol% increased the outlet CH 4 rather than aiding its decomposition. • CO 2 in the NG mixture decomposed into CO, implying non-zero GHG emissions. [ABSTRACT FROM AUTHOR]

The energy gap between primary sources of energy like coal, oil, and natural gas will be 14 TW by 2050, hence finding sustainable sources of energy is the need of the day to bridge this gap. Hydrogen (H 2) in water is freely and abundantly available in nature, thus, the effective combination of light energy and water to produce hydrogen in an environmentally acceptable manner has a great potential to meet the current as well as future world's energy demand. Several semiconductors (SC's) have been employed to catalyze the formation of hydrogen from water (H 2 O). But the practical and feasible applicability of this system is limited due to photocatalyst high energy demand via wide band gap, quick recombination of photoexcited charge carriers (electron/hole pairs), easy nanoparticles agglomeration in solution and low photocatalyst surface area for adsorption. The incorporation of the majestic graphene material with the SC alone or in multiple SC's system can improve photocatalytic H 2 -production. Therefore, this review systematically presents an overview of, to shape graphene into a photocatalyst, graphene role in water splitting and in the interfacial charge-migration dynamics at surface contacts. We also focused on the built-in mechanism of the heterostructures comprises of photocatalyst (mainly TiO 2 , ZnO and WO 3) and graphene-based nanomaterials (pure graphene (G), graphene oxide (GO), reduced graphene oxide (r-GO)) and their combination thereof for H 2 generation in aqueous system. Composite comprised of SC's/graphene could potentially be a promising green light in the future of solar energy-led photocatalysis, specifically aimed at energy production. • This article provides a comprehensive overview on SC's/G composites for H 2 production. • The charge carrier's mechanism was thoroughly discussed in different SC's/G hybrids. • Ternary SC's/G heterostructure performed well for H 2 evaluation. • Future research directions for SC's/G heterostructures are outlined. [ABSTRACT FROM AUTHOR]

One of the primary concerns with fuel combustion in internal combustion engines is the significant quantity of energy that is dissipated as waste heat, which leads to thermal pollution and reduced engine efficiency. To address this issue, a new integrated system incorporating a natural gas fueled homogeneous charge compression ignition (HCCI) engine for different hydrogen fractions (0%–20%) in fuel blends and its exhaust heat is recovered to drive the NH 3 –H 2 O based absorption refrigeration cycle (ARC) and process heat exchanger has been developed, which encompasses the generation of electricity, heating, and cooling. A comprehensive energy-exergy model was built and the impact of some key operating variables on the performance of combined system are investigated. Simulation of the proposed system was performed using Engineering Equation Solver (EES) software and REFPROP toolbox library data. The energy and exergy efficiencies of HCCI engine resulted in an increase from 45.26% to 55.45% and from 41.15% to 46.14%, whereas the combined system efficiencies were increased by 15.90% and 10.13% when hydrogen addition is promoted from 0% to 20%. Utilization of 10% hydrogen resulted in energy efficiency of 49.57% for electrical, 11.89% for cooling, and 4.51% for heating. Illustration of exergy flow diagram identified HCCI engine (118.29 kW, 32.11%) as the most fuel exergy destructive component, followed by ARC cycle (30.86 kW, 8.37%), catalytic converter (27.24 kW, 7.39%) and process heat exchanger (11.103 kW, 3.01%). Impressive exergetic results from the system include a power exergy of 158.91 kW (43.14%), heating exergy 10.697 kW (2.90%), and cooling exergy 3.92 kW (1.06%). • H 2 enriched natural gas fueled HCCI engine based trigeneration system was developed. • HCCI engine's exhaust waste heat was harnessed through the ARC cycle and PHE. • A single effect NH 3 –H 2 O absorption chiller was employed for cold production. • Energy and exergy-based assessment was carried out to analyze the proposed system. • HCCI engine (32.11%) were identified as the primary exergy destructive components. [ABSTRACT FROM AUTHOR]

Due to changes in urban residents' consumption habits and lifestyles, accurately predicting natural gas consumption has become increasingly important. To address this issue, this paper proposes a forecasting model that combines Ensemble Learning (EL), Variational Mode Decomposition (VMD), Transformer, and LSTM. First, XGBoost, CatBoost, and LightGBM are used as base learners in the ensemble learning framework, with the predictions generated by the ensemble model integrated into the original dataset. Next, the VMD method is employed to decompose the natural gas load sequence into several intrinsic mode functions (IMFs), effectively extracting the inherent features of the natural gas load sequence. Finally, the data is input into the Transformer-ResLSTM network for prediction. This network replaces the original Transformer decoder structure with an LSTM network and fully connected layers, creating a new decoder structure. Additionally, a residual connection mechanism is introduced in both the encoder of the Transformer network and the new decoder structure. Experimental results show that, compared to traditional models such as ARIMA, Transformer, GRU, and LSTM, the proposed hybrid model significantly improves prediction accuracy, reducing MSE by 92–98% and MAE by 74–83%. In summary, this method demonstrates significant potential and practical value in enhancing the accuracy of natural gas load forecasting. [ABSTRACT FROM AUTHOR]

This study investigates the relationship between consumer sentiment (CONS), inflation expectations (INEX) and international energy prices, drawing on principles from behavioral. We focus on Brent crude oil price and Henry Hub natural gas prices as key indicators of energy market dynamics. Based on the monthly data from January 2003 to March 2023, three wavelet methods are applied to examine the time-frequency linkage, while the nonlinear distributed lag model (NARDL) is used to verify the asymmetric impact of two factors on energy prices. The results highlight a substantial connection between consumer sentiment, inflation expectations and international energy prices, with the former in the short term and the latter in the medium to long term. Especially, these correlations are particularly pronounced during the financial crisis and global health emergencies, such as the COVID-19 epidemic. Furthermore, we detect short-term asymmetric effects of consumer sentiment and inflation expectations on Brent crude oil price, with the negative shocks dominating. The positive effects of these factors on oil prices contribute to observed long-term asymmetry. In contrast, inflation expectations have short-term and long-run asymmetric effects on natural gas price, and both are dominated by reverse shocks, while the impact of consumer sentiment on natural gas prices appears to be less asymmetric. This study could enrich current theories on the interaction between the international energy market and serve as a supplement to current literature. [ABSTRACT FROM AUTHOR]

Most of the implemented marine gas hydrate test exploitation in the world adopt the depressurization method to break down the hydrate in the reservoir into natural gas and then extract it, but because the gas production results are still a certain distance away from the commercial exploitation, and it mainly stays in the stage of theoretical research and trial exploitation. Based on two trial productions in the Shenhu area of the South China Sea, this study established a model for hydrate exploitation and investigated the impact of different well types on the recovery rates of hydrates and free gas in different development layers during depressurization. For the Class 1 hydrate reservoirs, horizontal wells are the optimal solution to extract hydrate and free gas simultaneously when exploiting the hydrate three-phase layer. Meanwhile, the effect of different well spacing in vertical wells on the recovery rate of hydrate and free gas was studied. It is found that the best recovery efficiency is achieved when the spacing between two wells is 80 m. The lower the bottom flow pressure of the well, the higher the production capacity, but its influence is limited. [ABSTRACT FROM AUTHOR]

Landfilled solid waste polymers were converted into high octane green fuels and hydrocarbons by a catalytic depolymerization process. Experiments were conducted in a batch catalytic reactor pressurized with methane as a co-feed. Design of Experiments (DOE) methodology was used for process optimization and parametric study. The operating conditions that maximize the liquids aromatic hydrocarbons were found using response optimizer tool. The reaction temperature and polymer to catalyst ratio (PCR) were found to have significant effects on the responses and methane pressure was not significant for yields of solids, liquids and gaseous products. However, pressurized methane facilitated dehydrocyclization reactions resulting in increased monoaromatic hydrocarbons in the final liquid products. Experiments conducted with methane feed at optimized reaction conditions resulted in 89% aromatic hydrocarbons, 8% paraffins and about 3% other hydrocarbons in liquid products. Aromatic products included benzene (6.5%), toluene (25%), xylenes (27%), ethylbenzene (4.5%), other monoaromatics (22%) and polyaromatic hydrocarbons (4%). Gaseous products contained propylene (47%) and hydrogen (23.9%). The utilization of waste polymers as feedstock materials, flare gas (methane) as a co-feed, and zeolite catalysts makes this batch zeolitic slurry process greener, resulting in green hydrocarbons and green fuels. [ABSTRACT FROM AUTHOR]

The mismatch between the rate of the new energy development and the system's peak-shaving capacity has resulted in severe wind abandonment. Based on the grid connection of wind power and natural gas peak-shaving, a model of unit commitment considering wind power consumption and natural gas peak-shaving and taking into account a combination of system economics and wind power consumption capability is designed. Natural gas peak-shaving is added to improve the system's peak-shaving capacity, and a wind abandonment penalty constraint is added to reduce the amount of wind abandoned by the system, and the model is solved by an improved genetic algorithm. Finally, to verify how wind power and natural gas peak-shaving impact unit commitment, the IEEE-30 node system is used. The results show that natural gas peak-shaving reduces system operating costs and improves the safety of the system. This model ensures the economics of system operation while positively promoting wind power consumption effectively and reasonably. [ABSTRACT FROM AUTHOR]

• A high cooling capacity Stirling cryocooler is developed to liquefy boil-off gas. • The relative Carnot efficiency of the cryocooler reaches 33.28% at 77 K. • The cryocooler is installed in the skid-mounted BOG liquefaction system. • The system produces 27.3 L/h LNG and shows a great application potential. Natural gas is a cost-effective energy supply for the development of low-carbon economy and environmental protection worldwide. Despite the environmentally friendly properties of natural gas, methane is a potent greenhouse gas. Therefore, efficiently recovering the boil-off methane gas (BOG) generated from liquefied natural gas (LNG) devices is becoming a pressing problem involving both the economy and the environment. The Stirling cryocooler is a promising technology in dealing with BOG. This technology has superior characteristics, including large cooling capacity, high efficiency, compact configuration, and flexible operating characteristics. In the study, a high cooling capacity Stirling cryocooler was developed. The influences of the regenerator on the cryocooler were studied. The refrigeration performance and the operating characteristics were systematically analyzed. A cooling power of 1050 W at 77 K with a relative Carnot efficiency of 33.28 % was achieved. Accordingly, the cryocooler outperforms the reported Stirling-type cryocoolers in terms of overall performance. A BOG liquefaction system based on the cryocooler was installed in an LNG refueling station. On-site test results demonstrated that the system can produce 27.3 L/h LNG with a power consumption of 14.5 kW. The present research lays a good foundation for future optimizations and applications of the cryocooler in liquefying BOG. [ABSTRACT FROM AUTHOR]

This article focuses on what kind of shortcomings Azerbaijan has in becoming the main energy supplier of the EU. The objective of this study is to analyse disadvantages of Azerbaijan via a mixed methodology which is based on discourses, data of Eurostat and description of political and geographical shortcomings of the country. Azerbaijan has both some advantages and disadvantages. The policy of neighbourhood relations is implemented between Azerbaijan and the EU. Azerbaijan is a country with which the EU has friendly relations in the Caucasus region. By analysing Azerbaijan's capacity, its importance and position for the EU can be emphasised. Data published by Eurostat are used in this study. According to these data, it can be stated that Russia is no longer a major supplier to the EU. The asymmetric interdependence between the EU and Russia in energy field has weakened as a result of the recent steps taken by European politicians. The USA, Qatar, Norway and the United Kingdom are among the new supplier countries. What role can Azerbaijan play in satisfying the EU's energy needs? In this article, I argue that Azerbaijan can be an important supplier to the EU, but it cannot become the main energy supplier. [ABSTRACT FROM AUTHOR]

This study analyzed the mechanical properties of reinforced concrete flexural and axial-tension members at low temperatures ranging from 273.15 to 108.15 K based on experimental and theoretical analyses. Special test chambers were used to separately apply mechanical forces and low temperatures to the test members. The steel strain caused by the mechanical and thermal restraint forces was obtained using the self-compensation test method. The effects of low temperatures on the tensile and flexural stiffness behaviors of reinforced concrete beams, as well as the internal forces generated because of the different linear expansion coefficients of concrete and steel at low temperatures, were analyzed. Analytical models were developed to predict the restraint stress corresponding to different temperatures. The accuracy of the analytical models was verified using the test results. The results show that the deformation stiffness of both flexural and axial-tension members increases linearly with decreasing temperature. The difference between the thermal deformation of concrete and steel bars becomes more considerable as the temperature decreases, resulting in nonnegligible restraint stress in the steel bars. The study can provide a basis for the design of structures in service at low and ultralow temperatures, such as liquefied natural gas storage tank structures. Practical Applications: Liquefied natural gas (LNG) is primarily composed of methane. After extraction from gas fields, it goes through a purification process; thereafter, it is subjected to a series of ultralow-temperature liquefaction steps and transported through specialized LNG carriers. LNG has extensive applications in various aspects of daily life, including energy supply, transportation, industrial use, and power generation. Compared with traditional fuels, LNG offers higher efficiency and environmental benefits. Nonetheless, optimizing the design of LNG storage facilities presents several technical challenges. Presently, reinforced concrete is the predominant material used in the construction of LNG storage facilities. To fully exploit the advantages of concrete structures in ultralow-temperature environments and reduce construction costs, comprehensive studies on the performance of concrete under such extreme conditions are crucial. This study is of immense scientific value and offers promising prospects for practical applications. [ABSTRACT FROM AUTHOR]

The discovery of new natural gas resources in the Eastern Mediterranean fueled the tension in the region and led to a highly complicated crisis involving multiple actors. This study adopts a constructivist approach in analyzing the political economy of the Eastern Mediterranean energy crisis by relying on the role of identities and ideas in shaping economic decisions. The historical enmity between Turkey and Greece over Cyprus is at the heart of the crisis. Thus, the study focuses on the Turkey, Greece, and Cyprus triangle to reveal the impact of Turkey's image constructed by Greece and the Republic of Cyprus, on the political-economic aspect of the decisions of Greece and Greek Cypriots. To accomplish this objective, a two-stage content analysis was conducted by filtering the official statements of Greece and the RoC from their respective foreign ministries, utilizing the keyword "Eastern Mediterranean." By scrutinizing the official discourses and documents, the analysis aims to delve into the image of Turkey held by these actors. [ABSTRACT FROM AUTHOR]

Tight sandstone reservoirs are significant sources of natural gas reserves. As traditional reserves become increasingly scarce and costly, optimizing the development of these reservoirs becomes crucial. This study introduces a novel two-phase gas–water flow model for single wells, incorporating both Darcy and non-Darcy flow equations. These equations are derived from mass conservation and momentum principles for both gas and water phases. Using data from a real tight gas well, our model, which includes stress-sensitive phases for gas and water, outperforms traditional Darcy flow models. Specifically, the average relative deviations in daily production rates were 0.1815% for gas and − 0.2677% for water, which are significantly smaller compared to traditional Darcy flow models. Further application of the non-Darcy flow model reveals strategies to enhance well performance. For example, mitigating liquid lock damage within a 2 m radius near the well could restore the permeability from 0.045 to 0.143 mD, thereby tripling the daily gas production. This non-Darcy flow model is easy to implement and shows significant potential in forecasting production yields in tight sandstone reservoirs, highlighting its importance in the petroleum and natural gas industry. [ABSTRACT FROM AUTHOR]

Using the staggered adoption of natural gas in China, we examine how energy substitution policy affects firm innovation. We find that firm innovation significantly increases following the passage of energy substitution policy. Moreover, the positive effect of energy substitution policy on firm innovation is more pronounced when firms are private, small-sized, located in low economic development regions. The channel test shows that firms adopting energy substitution policy can improve financial condition. Finally, we find that energy substitution policy has positive and significant effect on innovation productivity. [ABSTRACT FROM AUTHOR]

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The deep-processing utility of pure hydrogen sulfide (H2S) is a significant direction in natural gas chemical industry. Herein, a brand-new strategy of H2S conversion by a,b-unsaturated carboxylate esters into thiols or thioethers using task-specific carboxylate ionic liquids (ILs) as catalyst has been developed, firstly accomplishing the phase separation of product and catalyst without introducing the third component. It can be considered as a cascade reaction in which the product selectivity can be controlled by adjusting the molar ratio of H2S to a,b-unsaturated carboxylate esters. Also, the effects of ILs with different anions and cations, intermittent feeding operations, as well as pressure time kinetic behaviors on cascade reaction were investigated. Furthermore, the proposed interaction mechanism of H2S conversion using butyl acrylate catalyzed by [Emim][Ac] was revealed by DFT-based theoretical calculation. The approach enables the selfhase separation promotion of catalyst and product and achieves 99% quantitative conversion under mild conditions in the absence of solvent, making the entire process ecologically benign. High-efficiency reaction activity can still be maintained after ten cycles of the catalyst. Therefore, the good results, combined with its simplicity of operation and the high recyclability of the catalyst, make this green method environmentally friendly and costeffective. It is anticipated that this self-separation method mediated by task-specific ILs will provide a feasible strategy for H2S utilization, which will guide its application on an industrial scale. [ABSTRACT FROM AUTHOR]

The electricity system and the industrial sector interrelate on the path to decarbonization. The study addresses the drivers and environmental pressure within the industrial sector on the National Electricity System (NES). This article aims to characterize the metabolic pattern of the NES and the industrial sector using the Multiscale Integrated Analysis of Social and Ecological Metabolism (MuSIASEM) from a bioeconomic perspective to identify fields of opportunity in the regulatory policy instruments. A set of extensive and intensive variables (2019) on energy, production factors, and emissions was used at different hierarchical levels based on both subsectors. Our results show that the NES used primary energy sources (PES) and secondary energy carriers to fulfill its functions, of which 72% were domestic sources and 28% were imported. México imported 79.5% of the natural gas (NG) for electricity generation. However, there are favorable conditions for renewable PES to increase the installed capacity of solar plants between 3 and 4 orders of magnitude and 2–3 in wind power from the current capacity. NES's energy consumption per hour of human time is 17,388 MJ/h, with 65% being the heat equivalent to a total energy input consumed of 2139 PJ/y. Public plants contributed 43.7% to the generation, and the independent and self-supply producers the rest. End uses needed the supply of 69.3% of electricity from baseload plants. Sixty-three percent of the metabolic pattern of the industrial sector is based on heat and fuel processes, which depend on NG imports. The NES is reorganizing and recovering its energy autonomy. [ABSTRACT FROM AUTHOR]

AbstractThe creation, dissemination, and application of knowledge are crucial for achieving sustainable development and have been at the heart of international development efforts since World War II. In conventional international development cooperation, the Global North is portrayed as the provider of knowledge and material assistance, with the South often perceived as a more passive receiver. This approach perpetuates hierarchical knowledge-power relations, as what is considered the ‘best practices’ are usually based on experiences, ideologies, and ideals from the North. This paper critically examines the current role of Western development actors as providers of knowledge and policy, specifically in the formulation of good governance for natural gas resources in Tanzania. Following significant offshore natural gas discoveries between 2010–2015, Tanzania has garnered the attention of international energy companies, foreign donors, technical advisors, and consultants, all offering guidance and capacity-building expertise to ready the country for production. Drawing on interviews with key actors supported by secondary sources, this analysis depicts how hierarchical knowledge relations persist, but also highlights the contested and evolving nature of what constitutes good governance of natural gas resources. The paper underscores how context matters in petroleum resource governance and, more broadly, the necessity for contextualising knowledge in international development cooperation. [ABSTRACT FROM AUTHOR]

The utilization of hydrogen (H 2) instead of natural gas (NG) in high-temperature industries has the potential to significantly reduce global greenhouse gas emissions. To obtain detailed information on the combustion characteristics in a semi-industrial air–fuel setup, comprehensive experiments and 3D CFD simulations are performed on a low-swirl burner inside a combustion chamber. The H 2 enrichment in NG of 0–100 vol % is analyzed at burner powers of 75–120 kW and temperatures of 900–1400 ° C. The process efficiency increases by up to 10 percentage points due to higher temperatures and enhanced heat transfer. Furthermore, up to 20% lower NO x emissions are observed, which is attributed to a significant change in the flow and flame characteristics. For the first time, OH* chemiluminescence imaging is successfully applied to validate RANS simulations of an industrial turbulent flame. Further research should be directed toward evaluating OH* reaction kinetics in both laminar and turbulent NG/H 2 combustion setups. • H 2 enrichment of up to 100 vol% at powers of 75–120 kW and temperatures of 900–1400 °C. • Effect on furnace temperatures, heat transfer characteristics and NO x emissions. • Accurate and efficient 3D RANS simulation model for a detailed flame evaluation. • Novel validation method for industrial-type flame simulation using OH* imaging. • Correspondence of NG/H 2 induced OH*-chemiluminescence with 3D numerical OH*-results. [ABSTRACT FROM AUTHOR]

We investigate the challenges and options for repurposing existing natural gas pipelines for hydrogen transportation. Challenges of re-purposing are mainly related to safety and due to the risk of hydrogen embrittlement of pipeline steels and the smaller molecular size of the gas. From an economic perspective, the lower volumetric energy density of hydrogen compared to natural gas is a challenge. We investigate three pipeline repurposing options in depth: a) no modification to the pipeline but enhanced maintenance, b) use of gaseous inhibitors, and c) the pipe-in-pipe approach. The levelized costs of transportation of these options are compared for the case of the German Norddeutsche Erdgasleitung (NEL) pipeline. We find a similar cost range for all three options. This indicates that other criteria such as the sunk costs, public acceptance, and consumer requirements are likely to shape the decision making for gas pipeline repurposing. • Three options for repurposing a natural gas pipeline to use with hydrogen are considered. • The levelized costs of hydrogen transport of each option are calculated. • The calculations are for the case study of the NEL pipeline in Germany. • Levelized costs of hydrogen transport are similar between the three options. [ABSTRACT FROM AUTHOR]

Hydrogen has enormous potential for sustainable future mobility. However, current challenges include high production costs and storage issues, necessitating further engineering advancements. Compressed Natural Gas is also a viable alternative, as it is easily produced and stored but suffers from slow flame speed-related issues. Improving its combustion characteristics by enrichment using a small fraction of hydrogen holds significant promise. Inducting hydrogen directly into the combustion chamber improves the engine's volumetric efficiency, eliminating the backfire issues. However, it is crucial to understand the test fuel's jet and mixing characteristics before engine investigations. This study aims to analyse the macroscopic jet characteristics of hydrogen, compressed natural gas and hydrogen-enriched compressed natural gas in realistic engine-like conditions in a constant volume spray chamber at various fuel injection pressures and varying ambient pressures and temperatures. Fuel injection pressures for hydrogen and CNG were varied at 16, 32, and 48 bar, and ambient pressures in the constant volume spray chamber were set at 4- and 8-bar and ambient temperatures at 25 and 100 °C. The results showed hydrogen exhibited ∼2% shorter jet penetration length than compressed natural gas. Depending on the test conditions, hydrogen showed a ∼1–3% higher jet area than CNG due to its higher diffusivity and faster mixing. This higher jet area improved fuel-air mixing of hydrogen with air compared to CNG. The effect of hydrogen enrichment with CNG on their jet characteristics was also analysed for 8 bar FIP. 10% (v/v), 20%, and 40% hydrogen-enriched compressed natural gas did not significantly alter the macroscopic jet characteristics from baseline compressed natural gas. [Display omitted] • Macroscopic spray characterization of hydrogen and CNG in CVSC using Schlieren. • FIP for hydrogen and CNG was varied at varying ambient pressures/temperatures. • Hydrogen exhibited a ∼2% shorter spray jet penetration length than CNG. • Hydrogen showed a larger spray area than CNG. • Hydrogen enrichment of CNG didn't alter macroscopic spray characteristics. [ABSTRACT FROM AUTHOR]

A well-connected network formed by multi-scale fractures is a key factor in the formation of high-quality reservoirs and the achievement of high and stable oil and gas production in tight sandstones. Taking the Upper Paleozoic of the Qingshimao gas field in the Ordos Basin, China, as an example, based on data from image logs, cores, and thin sections, fine quantitative characterization of multi-scale natural fractures in tight sandstone reservoirs was carried out. We also established a method for dividing network patterns of multi-scale fractures and discussed the effect of each fracture network pattern on the gas enrichment and production capacity. Results indicate regular changes in the length, density, aperture, porosity, permeability, and connectivity of natural fractures at different scales. Based on the spatial combination patterns and connectivity of fractures of different scales, four types of fracture network patterns were established: multi-scale fracture network with high density and multi-orientations, multi-scale fracture network with moderate-high density and dual orientations, small-scale fracture network with moderate density and dual orientations, small-scale fracture network with low density and single orientation. The first fracture network pattern can destroy the integrity of the cap layer, causing natural gas leakage. The second fracture network pattern is a favorable area for natural gas enrichment. The third fracture network pattern requires the use of hydraulic fracturing to obtain commercial airflow. The fourth fracture network pattern has little effect on reservoir control and storage. The study of natural fractures in tight sandstone reservoirs is usually based on a single-scale perspective. Understanding the development characteristics of multi-scale fractures and their controlling effects on the reservoir helps to comprehensively understand the spatial configuration relationship of multiscale fracture network structure patterns and promotes the development of multi-scale fractures in tight reservoir research. [ABSTRACT FROM AUTHOR]

Enriching methane from sources such as natural gas, biogas, and coalbed methane is a valuable gas separation endeavor, given methane as a cleaner and more sustainable fuel resource. Pressure swing adsorption (PSA) is widely regarded as a mature technology for this purpose. The essence of the mathematical model is to capture the fundamental aspects of the problem, enabling an accurate description of the system. This review summarizes recent trends in the mathematical modelling of PSA for methane enrichment. It provides a comprehensive compilation of numerical modelling and simulation studies, with a critical emphasis on methane enrichment applications. A rigorous mathematical model describing the adsorption phenomenology in a packed bed column is presented, incorporating mass, momentum, and energy balances, which serve as the fundamental framework for the cyclic adsorption process. Key analyses and performance metrics of PSA systems are detailed through examples from the literature. A case study based on a single column is presented to exemplify the mathematical modelling pathway and serve as a basis for model validation. The paper concludes by highlighting instructive avenues for future research directions and development in this area. [ABSTRACT FROM AUTHOR]

Highlights This work investigates the comprehensive exploration of transport properties in natural rubber/graphene oxide‐silica hybrid core‐shell (NR/GSC) nanocomposites, focusing on diffusion, sorption behavior, swelling parameters, and gas permeability. The study evaluates the performance of the composite membranes concerning oxygen and nitrogen gas permeability (71.3% and 68.48% reduction, respectively). The experimental results reveal the sorption behavior, swelling parameters, and transport coefficients of NR/GSC composites, providing valuable insights into the material's behavior in different environments. Among various compositions, GSC10 stands out as the optimal composition, exhibiting superior diffusion and gas permeability behavior compared to other compositions. How the filler geometry and concentration are interconnected on the transport properties is carefully dissected, offering a deeper comprehension of the correlation between filler characteristics and composite performance. The study predicts that the Peppas‐Sahlin model and Affine model for mole percentage solvent uptake and molecular mass between successive crosslinks, respectively, best fit experimental values. This work contributes to the growing knowledge in the field of nanocomposites, providing a meticulous perspective on the transport properties of NR/GSC membranes and emphasizing the superior performance of the GSC10 composition. NR/GSC hybrid nanocomposites showed reduced solvent uptake. A 71.3% reduction in oxygen and 68.48% reduction in nitrogen permeation. Theoretically modeled using Peppas‐Sahlin, Korsmeyer‐Peppas, Nielsen and s GSC nanoparticles shows excellent dispersion in NR matrix Enhanced fuel efficiency and reduced environmental footprint in tire manufacturing technology. [ABSTRACT FROM AUTHOR]

It is of great significance for deep oil and gas exploration to understand the origin and evolution behind overpressure. Overpressure occurs in the deep Shahezi Formation of Xujiaweizi fault depression. However, due to limited degree of exploration, there are some problems in the study area, such as unclear understanding of the origin of overpressure and the vague investigation of overpressure evolution. To clarify the impact of overpressure on oil and gas migration and accumulation in the study area, this study focuses on the research of the origin and evolution of overpressure in the Shahezi Formation of the study area, utilizing single well logging parameters and combining methods such as microthermometry of fluid inclusions, laser Raman spectrum, and basin simulation. The results show that the overpressure of the Shahezi Formation in Xujiaweizi fault depression is primarily generated by hydrocarbon generation pressurization, and the evolution of overpressure is closely related to hydrocarbon generation. The development of overpressure can be divided into two evolutionary stages: early hydrocarbon generation pressurization and late uplift release, with slight variations in different regions. Tight glutenite gas reservoirs in the Shahezi Formation are characterized by continuous charging. The overall charging period ranges from the late Denglouku to the early Mingshui (110‐67 Ma ago). There is an obvious paleo‐overpressure during the gas reservoir formation period. The gas generation period of source rocks occurred approximately 125‐60 Ma ago, and the main gas generation period (112‐67 Ma ago) highly coincides with the period of natural gas charging. The anomalously high pressure during the accumulation period is considered the significant driving force for natural gas charging. In addition, the sustained effect of overpressure provides better conditions for the preservation of tight gas reservoirs within the source. The results of the study are of guiding significance for the in‐depth exploration and development of deep tight sandstone gas in the Shahezi Formation of Xujiaweizi fault depression. [ABSTRACT FROM AUTHOR]

The addition of hydrogen in a dual-fuel mode based on natural gas and diesel offers great potential for improving engine efficiency and reducing emissions. Therefore, detailed numerical simulations have been used to explore the effects of soot formation characteristics of natural gas-diesel dual-fuel engines doped by hydrogen at elevated pressure. Numerical simulations are compared with available experimental data, the effects of H 2 addition on soot formation in laminar CH 4 + n-heptane, H 2 + CH 4 + n-heptane, FH 2 + CH 4 + n-heptane diffusion flames at 2, 4, 6 and 8 atm are simulated, FH 2 is added to separate the H 2 chemical effects. The results show that the dilution and thermal effects of H 2 inhibit soot formation, while the chemical effects of H 2 promote soot formation under different pressures. The addition of H 2 increases the concentration of H and OH radicals, which promotes the formation of C 2 H 2 and benzene (A1). By simplifying the reaction path and analyzing the production rate of A1, the mechanism of H 2 addition to promote A1 formation is illustrated. The concentrations of polycyclic aromatic hydrocarbon (PAH) pyrene (A4), benzo(ghi)fluoranthene (BGHIF) and benzo(a)pyrene (BAPYR) are inhibited at higher pressures that result in lower inception and condensation rates. Therefore, the increase of hydrogen abstraction acetylene addition (HACA) rate is the main reason for the increase of soot formation under chemical effects. While the O 2 oxidation rate decreases and the OH oxidation rate increases, that is due to the decrease of O 2 concentration and the increase of OH concentration in the soot formation area under chemical effects. • The dilution, thermal and chemical effects of H 2 addition on soot formation in methane/n-heptane flame were investigated at high pressures. • Key specie A1 formation pathways and related reactions were confirmed when H 2 addition. • The changes of soot formation and oxidation mechanisms with H 2 addition in different pressure were explained. [ABSTRACT FROM AUTHOR]

In this study, three premixed swirl gas turbine nozzles with different fuel injection hole sizes were designed to optimize combustion characteristics influenced by changes in the hydrogen mixing ratio. Experiments involved increasing the hydrogen volume fraction of the fuel from 0 to 60%. The amount of fuel supplied through the pilot flow was increased to suppress combustion instability. The OH* chemiluminescence technique was introduced to analyze flame structure. To understand combustion instability, time delay and time-delay distribution were derived from flame structure analysis and applied to the 1D thermoacoustic model. The results indicated that the amount of fuel required for pilot injection with increasing hydrogen ratio varied with fuel hole size. It was also observed that changes in fuel hole size significantly affected flame characteristic length. Findings from the 1D thermoacoustic analysis confirmed that fuel hole size variation altered combustion instability characteristics by influencing time delay and time-delay distribution variation. [Display omitted] • This study investigated the impact of fuel hole size for H 2 co-firing. • Increase in H 2 fraction reduced flame length and heat release distribution. • Fuel hole size variation affected time delay and its distribution. • Changing the time delay and its distribution influenced combustion instability. [ABSTRACT FROM AUTHOR]

One of the current trends in the complex processing of fine dust from copper smelters is their direct leaching with sulfuric acid. As practical results show, high reliable technological parameters are not achieved due to the high content of arsenic in dust. During sulfuric acid leaching of dust, arsenic is distributed between the lead cake and the solution at a ratio of 40 and 60%, respectively. The redistribution of arsenic between leaching products significantly reduces the technological performance and leads to the accumulation of arsenic in the technological scheme. The paper presents the results of comprehensive studies of the elemental and phase composition of fine dust from one of the copper smelters in Kazakhstan. In the initial dust, along with the main phases presented in the form of lead and zinc sulfate, the following typical components were found: oxides of copper, lead, zinc and copper and zinc ferrites. Arsenic is found in two forms—As(III) and As(V). The laboratory installation and technique for conducting reduction roasting of dust with natural gas are presented. The influence of roasting duration, temperature and natural gas consumption on the extraction of arsenic from dust was studied. It has been established that almost complete, up to 99%, extraction of arsenic from dust is achieved with optimal technological roasting parameters: duration τ = 40 min.; natural gas consumption is 1.5 times higher than the stoichiometrically required amount for the reduction of As2O5, and temperature 500 °C. [ABSTRACT FROM AUTHOR]

Hydrogen, as an energy carrier, is attractive to many stakeholders based on the assumption that the extensive global network of natural gas infrastructure can be repurposed to transport hydrogen as part of a zero‐carbon energy future. Therefore, utility companies and governments are rapidly advancing efforts to pilot blending low‐carbon hydrogen into existing natural gas systems, many with the goal of eventually shifting to pure hydrogen. However, hydrogen has fundamentally different physical and chemical properties to natural gas, with major consequences for safety, energy supply, climate, and cost. We evaluate the suitability of using existing natural gas infrastructure for distribution of hydrogen. We summarize differences between hydrogen and natural gas, assess the latest science and engineering of each component of the natural gas value chain for hydrogen distribution, and discuss proposed solutions for building an effective hydrogen value chain. We find that every value chain component is challenged by reuse. Hydrogen blending can circumvent many challenges but offers only a small reduction in greenhouse gas emissions due to hydrogen's low volumetric energy density. Furthermore, a transition to pure hydrogen is not possible without significant retrofits and replacements. Even if technical and economic barriers are overcome, serious safety and environmental risks remain. [ABSTRACT FROM AUTHOR]

Accurately determining if the sample parameters from a natural gas pipeline's sampling system reflect the fluid characteristics of the main pipe has been a significant industry concern for many years. In this paper, samples of natural gas in a horizontal pipeline are investigated. CFD is used in this work and the turbulence is considered in the simulation. Firstly, the critical diameter for particles affected by gravity within such pipeline is determined. And then, the effects of the operation pressure and velocity of sampling branches on sample parameters, and the influence of particle density on these sample parameters, are analyzed. Finally, four different structures of sample branches for natural gas in a horizontal pipeline are compared. It is found that 100 μm is the critical diameter at which particles are affected by gravity; the operating pressure of the sampling branch has a significant impact on the particle mass concentration. The particle density has little impact on the sampling system. Overall, the design of the sampling branches does not cause significant sampling errors. This study provides guidance for optimal sampling in existing natural gas pipelines and enables effective monitoring of particle impurity content and properties in natural gas. [ABSTRACT FROM AUTHOR]