Primary Gas Research Articles

Ice Core Methane Analytical Techniques, Chronology and Concentration History Changes: A Review

Ice cores are invaluable in paleoclimate research, offering unique insights into the evolution of the natural environment, human activities, and Earth’s climate system. Methane (CH4) is a crucial greenhouse gas, second only to CO2 in its contribution to global warming, and is one of the primary anthropogenic greenhouse gases. Understanding historical CH4 concentration changes is essential for predicting future trends and informing climate change mitigation strategies. By analyzing gas components trapped in ice core bubbles, we can directly examine the composition of ancient atmospheres. However, there are relatively few comprehensive reviews on ice core CH4 testing techniques, chronology, and concentration history records. In response to this gap, our paper systematically reviews ice core CH4 analytical techniques, chronology, and concentration history changes. Our review indicates that current research on CH4 in non-polar ice cores is insufficient compared to polar ice cores, facing challenges such as high data dispersion, outlier frequency, and the presence of non-atmospheric signals. These limitations hinder our in-depth understanding of CH4 signals in non-polar ice cores, and the reliability of atmospheric CH4 concentration changes they reflect. To address these challenges, we propose exploring and applying advanced testing techniques, such as Continuous Flow Analysis technology, in non-polar ice cores. Additionally, we emphasize the research gap in utilizing CH4 records for age determination in ice core chronology. Future research should focus on this area to advance our understanding of ice core chronology and the history of atmospheric CH4 changes in non-polar regions, ultimately contributing to more effective climate change mitigation efforts.

Sensitivity of pollutant concentrations in urban streets to asphalt and traffic-related emissions

The higher concentrations of atmospheric particles, such as black carbon (BC) and organic matter (OM), detected in streets compared to the urban background are predominantly attributed to road traffic. The integration of this source of pollutant in air quality models nevertheless entails a high degree of uncertainty and some other sources may be missing. Through sensitivity scenarios, the impacts on pollutant concentrations of sensitivities related to traffic and road-asphalt emissions are evaluated. The 3D Eulerian model Polair3D and the street network model MUNICH are applied to simulate various scenarios and their impacts at the regional and local scales. They are coupled with the modular box model SSH-aerosol to represent formation and aging of primary and secondary gas and particles. Traffic emissions are calculated with the COPERT methodology. Using recent volatile organic compound speciations for light vehicles with more detailed information pertaining to intermediate, semi- and low-volatile organic compounds (I/S/LVOCs) leads to limited reductions of OM concentrations (10% in streets). Changing the method of estimating I/S/LVOC emissions leads to an average reduction of 60% at emission and a decrease of the OM concentrations of 27% at the local scale. An increase in 219% of BC emissions from tire wear, consistent with the uncertainties found in the literature, doubles the BC concentrations at the local scale, which remain underestimated compared to observations. I/S/LVOC emissions are several orders of magnitude higher when considering emissions from road asphalt due to pavement heating and exposure to sunlight. However, simulated concentrations of PM at the local scale remain within acceptable ranges compared to observations. These results suggest that more information is needed on I/S/LVOCs and non-exhaust sources (tire, brake and road abrasion) that impact the particle concentration. Furthermore, currently unconsidered emission sources such as road asphalt may have non-negligible impacts on pollutant concentrations in streets.

Decarbonizing the Spanish transportation sector by 2050: Design and techno-economic assessment of the hydrogen generation and supply chain

The transport sector is difficult to decarbonize due to its high reliance on fossil fuels, accounting for 37% of global end-use sectors emissions in 2021. Therefore, this work proposes an energy model to replace the Spanish vehicle fleet by hydrogen-fueled vehicles by 2050. Thus, six regions are defined according to their proximity to regasification plants, where hydrogen generation hubs are implemented. Likewise, renewables deployment is subject to their land availability. Hydrogen is transported through an overhauled primary natural gas transport network, while two distribution methods are compared for levelized cost of hydrogen minimization: gaseous pipeline vs liquid hydrogen supply in trucks. Hence, a capacity of 443.1 GW of renewables, 214 GW of electrolyzers and 3.45 TWh of hydrogen storage is required nationwide. Additionally, gaseous hydrogen distribution is on average 17% cheaper than liquid hydrogen delivery. Finally, all the regions present lower prices per km traveled than gasoline or diesel.

Development characteristics and main controlling factors of Carboniferous volcanic reservoirs in the Shixi area, Junggar Basin

The Carboniferous volcanic reservoirs in the Shixi area of the Junggar Basin are complex and diverse. Identifying the characteristics and main factors controlling high-quality volcanic reservoirs is the key to increasing oil and gas reserves and production in this area. Through core observations, thin section identification, physical property and pore structure analyses, combined with production data, the main controlling factors and development modes of high-quality reservoirs were analysed. The results show that the Carboniferous strata in the Shixi area mainly contain andesite and dacite of overflow facies, followed by volcanic breccia and tuff of explosive facies. Volcanic reservoirs in the study area are high-porosity–low-permeability and medium-porosity–low-permeability reservoirs. Volcanic breccia of explosive facies has the best physical properties, showing the characteristics of high porosity and medium permeability. The reservoir space is mainly composed of gas cavities, corrosion pores and fractures, among which the corrosion pores are the most important reservoir spaces of the Carboniferous volcanic rocks. Lithology and lithofacies, weathering and corrosion, and fractures are the main factors controlling the development of high-quality volcanic reservoirs. Volcanic rocks that had experienced weathering and denudation for a long time developed a large number of secondary corrosion pores due to the corrosion of soluble minerals or volcanic ash. Fractures further improved the physical properties, causing volcanic rocks to eventually develop into weathering crust reservoirs. The physical properties of the volcanic rocks far away from the weathering crust were improved through primary gas cavities and structural fractures, and these volcanic rocks eventually developed into the inner reservoir.

Differential Enrichment Regulation and Genetic Analysis of Tight Sandstone Gas Reservoir

In the deep Paleogene of graben basins in eastern China, not only the tight sandstone oil and gas resources, but also the secondary hydrocarbon generation of source rocks are universal and worth studying. In order to elucidate the laws of oil and gas accumulations in tight sandstone with different phases and explore the diversity of its genetic mechanism, Shahejie Formation in Wendong area was taken as an example in this paper to carry out further research. Firstly, the differential enrichment rules of oil and gas reservoirs are clarified from the aspects of spatial distribution, phase type and fluid properties. Secondly, the reasons for differential accumulation of oil and gas reservoirs were analyzed from multiple perspectives by using a variety of methods, such as source rock thermal evolution simulation, fault activity evaluation and reservoir porosity evolution. A large number of researches have been carried out on hydrocarbon generation and expulsion process of source rocks, paleo-temperature and paleo-pressure changes, the connectivity of skeleton sand bodies, reservoir physical property and densification process, tectonic strength and so on. The results indicate that the deep tight sandstone reservoirs of the Paleogene in the Wendong area have a quasi-continuous distribution characteristic of "planar partition and longitudinal zoning". Secondary kerogen cracking gas, crude oil cracking gas, medium light crude oil, and primary kerogen cracking gas are distributed in a semi-circular manner, from the center of Qianliyuan Sag to Wendong graben and rollover anticline belt at the high structural position. In conclusion, the two periods of hydrocarbon generation and expulsion of source rocks lead to the discontinuity of hydrocarbon accumulation process. Paleo-temperature and paleo-pressure conditions control the phase types of hydrocarbon filling. The lateral connectivity and the difference of physical properties of the skeleton sand bodies limit the distribution range of oil and gas reservoirs. The temporal and spatial availability of faults during the critical accumulation period determines the differential enrichment of oil and gas. The temporal and spatial validity of faults during the critical accumulation period determines the extent of differential enrichment of oil and gas.

Role of Mutual Diffusion in the Dissolution Behavior of One Primary Bulk Gas Nanobubble in Liquid: A Molecular Dynamics Study.

Dissolution of one primary bulk gas nanobubble in an undersaturated liquid constitutes one of the underlying issues of the exceptional stability of bulk gas nanobubble population. In this paper, the mutual diffusion coefficient at the gas-liquid interface of one primary bulk gas nanobubble is investigated via all-atom molecular dynamics simulation, and the applicability of the Epstein-Plesset theory is verified. The mutual diffusion coefficient, different from the self-diffusion coefficient in bulk gas or bulk liquid, is essentially determined by the chemical potential due to its driving role in the mass transfer across the interface. We could ascribe the low-rate dissolution of one primary bulk gas nanobubble in an undersaturated liquid to the slight attenuation of the mutual diffusion coefficient at the interface. The results show that the dissolution process of one primary bulk gas nanobubble in an undersaturated liquid fundamentally obeys the Epstein-Plesset theory and that the macroscopic dissolution rate is intrinsically determined by the gas mutual diffusion coefficient at the interface rather than the self-diffusion coefficient in the bulk phase. The mass transfer viewpoint from the present study might actively promote subsequent studies on the super-stability of bulk gas nanobubble population in liquid.

Compositional Mixing Characteristics of Separate Gas and Oil Charges into Oil Field Reservoirs

Many reservoirs worldwide received separate charges of primary biogenic gas and oil. In high pressure provinces such as the Gulf of Mexico, the added gas should be in solution if thoroughly mixed. In addition, this biogenic gas is easily differentiated from thermogenic gas by measurement of methane carbon isotopes and gas composition. Consequently, the extent of mixing can be determined with accuracy, and the gas and oil mixing processes depend on specifics of reservoir charging and can lead to multiple outcomes. The conventional expectation is that the biogenic gas always precedes oil entry into the reservoir. Here, chemical evaluation of reservoir fluids coupled with reservoir understanding of several reservoirs establishes that the oil can arrive prior to biogenic gas. Seismic imaging of gas chimneys provides a plausible explanation for how this can occur. In addition, thermodynamic and geochemical evaluation of the reservoir fluids across the reservoir tightly constrains possible mixing processes. Simple reservoir simulation shows that excellent gas and oil mixing can occur over a wide range of conditions provided that the gas charges into the oil column at its bottom (at the oil–water contact). This modeling exhibits simple fluid mechanics expectations for this reservoir charging process. In addition, since the increase of solution gas destabilizes asphaltenes, fluid geodynamic processes are indicated that can lead to redistributions of asphaltenes. Evaluation of gas and oil mixing processes in reservoirs fits within the framework of the powerful new technical discipline, reservoir fluid geodynamics, for subsurface characterization.

The Change of Global Temperature Affected by Global Economy

Global warming is the most serious environmental problem due to rising temperatures. Previous studies showed CO2 is the primary greenhouse gas. CO2 emission is caused by the burning of fossil fuels. Humans pursue industrial growth at the expense of releasing CO2 into the atmosphere. Economic development is represented by Gross Domestic Product (GDP). The growth of CO2 emission increases more and more and does not reach the peak. The global temperature is facing a 2˚C crisis. The global emissions and global economy have a strong indication of relative sensitivity. We found out that countries with higher GDP emit more CO2. Individuals who have higher GDP per capita emit more CO2 to the atmosphere. GDP has a positive correlation with global temperature. Climate change is one of the biggest inequalities around the world. Richer countries caused more damage to global warming, but poor countries suffer more from global warming’s damage. GDP per capita has a positive correlation with temperature and CO2 emissions. The development of a country has a trend of increasing CO2 emissions at an early stage and decreasing CO2 emissions at a later stage. Total GDP although cannot positively correlated to CO2 emissions, but multicollinearity tests proved the two variables are related.

House ammonia exposure causes alterations in microbiota, transcriptome, and metabolome of rabbits.

Pollutant gas emissions in the current production system of the livestock industry have negative influences on environment as well as the health of farm staffs and animals. Although ammonia (NH3) is considered as the primary and harmful gas pollutant in the rabbit farm, less investigation has performed to determine the toxic effects of house ammonia exposure on rabbit in the commercial confined barn. In this study, we performed multi-omics analysis on rabbits exposed to high and low concentration of house ammonia under similar environmental conditions to unravel the alterations in nasal and colonic microbiota, pulmonary and colonic gene expression, and muscular metabolic profile. The results showed that house ammonia exposure notably affected microbial structure, composition, and functional capacity in both nasal and colon, which may impact on local immune responses and inflammatory processes. Transcriptome analysis indicated that genes related to cell death (MCL1, TMBIM6, HSPB1, and CD74) and immune response (CDC42, LAMTOR5, VAMP8, and CTSB) were differentially expressed in the lung, and colonic genes associated with redox state (CAT, SELENBP1, GLUD1, and ALDH1A1) were significantly up-regulated. Several key differentially abundant metabolites such as L-glutamic acid, L-glutamine, L-ornithine, oxoglutaric acid, and isocitric acid were identified in muscle metabolome, which could denote house ammonia exposure perturbed amino acids, nucleotides, and energy metabolism. In addition, the widespread and strong inter-system interplay were uncovered in the integrative correlation network, and central features were confirmed by in vitro experiments. Our findings disclose the comprehensive evidence for the deleterious effects of house ammonia exposure on rabbit and provide valuable information for understanding the underlying impairment mechanisms.

Effect of Iron Component on the Structural Evolution of Carbon Bonds in Hydrochloric Acid-Demineralized Lignite During Pyrolysis.

The pyrolysis characteristics of hydrochloric acid-demineralized Shengli lignite (SL+) and iron-added lignite (SL+-Fe) were investigated using a fixed-bed reactor. The primary gaseous products (CO2, CO, H2, and CH4) were detected via gas chromatography. Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy techniques were used to study the carbon bonding structures of the lignite and char samples. In situ diffuse reflectance infrared Fourier transform spectroscopy was used to better understand the effect of the iron component on the transformation of the carbon bonding structure of lignite. The results showed that CO2 was released first during pyrolysis, followed by CO, H2, and CH4, and this order was unaffected by the addition of the iron component. However, the iron component promoted the generation of CO2, CO (<340 °C), and H2 (<580 °C) at lower temperatures and inhibited the formation of CO and H2 at higher temperatures while also inhibiting the release of CH4 throughout the pyrolysis process. The iron component may form an active complex with C=O and a stable complex with C-O, which can promote the fracture of carboxyl functional groups and inhibit the decomposition of ether bonds, phenolic hydroxyl groups, methoxy groups, and other functional groups, thus promoting the decomposition of aromatic structures. At low temperatures, it promotes the decomposition of aliphatic functional groups and finally the bonding and fracture of functional groups in coal, leading to the change of the carbon skeleton, resulting in the change of gas products. However, it did not significantly affect the evolution of -OH, C=O, C=C, and C-H functional groups. According to the above results, a developing reaction mechanism model of Fe-catalyzed lignite pyrolysis was established. Therefore, it is worth doing this work.

Thermal analysis technology to utilize waste biomass and waste heat to produce high-quality combustible gas through simulations and experiments

To ensure the proper utilization of waste biomass (WB) and high-temperature waste heat, this study proposes a new method for obtaining gaseous fuels by pyrolyzing WB and using waste heat in the converter vaporization cooling flue (CVCF). This study is theoretically based on the simulation software Factsage 6.1 and the release patterns of the gaseous products including CO, H2, CH4 and CO2 obtained from waste biomass, were studied at different temperatures and pressures. Thermogravimetric-mass spectrometer (TG-MS) was used to investigate the pyrolysis of WB at heating rates of 5, 10, 15, and 20 °C/min from room temperature to 1400 °C. Kinetics parameters were calculated by using the Flynn-Wall-Ozawa (FWO) and Kissinger-Akahira-Sunose (KAS) models. To investigate the effects of temperature, a settling furnace was also used to simulate CVCF. Thermal decomposition produced the primary gases namely CO, CH4, and H2. Pyrolysis had an average activation energy of 183.29 kJ/mol. As the temperature increased from 800 °C to 1200 °C, the CO content increased from 39.7 % to 48.9 % and the H2 content increased from 35 % to 45.1 %. As the temperature rose from 800 to 1200 °C, the lower heating value (LHV) increased from 11.38 to 12.05 MJ/Nm3. The findings primarily confirmed the feasibility of injecting biomass into the CVCF to generate gaseous fuels from waste heat.

Inventory of PCDD/Fs and Fly Ash Characteristics during the e-Waste and Municipal Solid Waste Co-Incineration Process

In the face of a challenging situation for yearly e-waste (EW) increment and disposition, EW co-incineration (EWC) with municipal solid waste (MSW) is a promising solution whose emission characteristics remain unclear. This study is conducted in a 400 tons/day MSW incineration (MSWI) plant to characterize polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and fly ash (FA) properties. Analytical methods include high-resolution gas chromatography/high-resolution mass spectrometry (HRGC/HRMS) for PCDD/F determination, as well as X-ray diffraction (XRD), X-ray fluorescence (XRF), ion chromatography (IC), and leaching toxicity test for FA. The results indicate that toxic PCDD/F amounts are doubled by EWC in both primary exhaust gas (EG) and FA with international toxic equivalent quantity (I-TEQ) concentrations of 19.00 ± 6.32 ng I-TEQ/Nm3 and 1.33 ± 0.56 ng I-TEQ/g. After the clean-up of the air pollution control system (APCS), emitted PCDD/Fs in solid and gas phases, as well as major air pollutants (CO, NOx, SO2, HCl, and particulate matter), are permissive within the limit values of national standards GB 18485-2014 and GB 16889-2008. Distribution patterns for 136 PCDD/F isomers are analogous in both MSWI and EWC conditions. De novo synthesis is always the major formation route for both EWC and MSWI conditions, while dibenzodioxin/dibenzofuran (DD/DF) chlorination also contributes. The generation of 136 PCDD/Fs is enhanced by EWC, and the correlation coefficients of Cl and Cu in the fuel with the generation of 136 PCDD/F isomers are found to be R = 0.92 and 0.88, respectively. The main components in FA from MSWI and EWC differ less, both containing CaO, SiO2, and Al2O3. However, Cl and Cu contents, as well as leaching toxicity in FA are elevated by EW. Heavy metals, except for Cd, Ni, and Pb, meet the requirement of the standard.

Understanding landfill gas behavior at elevated temperature landfills

Landfill gas (LFG) wellhead data were compared to understand the range of observations due to unique conditions at five elevated temperature landfills (ETLFs) in the U.S. Correlations of the primary gas ratio, CH4:CO2, show distinct compositional indicators for (1) typical operation, (2) subsurface exothermic reactions (SERs), (3) high moisture content, and (4) air intrusion that can help operators and regulators diagnose conditions across gas extraction wells. ETLFs A, B, D, and E showed similar trends, such as decreasing CH4 and increasing CO2, CO, and H2 that have been previously described. ETLF C uniquely exhibited elevated CH4 and temperatures simultaneously due to carbonation (i.e., CO2 consumption) of a steel slag which was used as alternative daily cover (ADC). At the maximum gas well temperature, T = 82 °C/180 °F, CH4 and CO2 concentrations were 47% and 28%, respectively. At ETLFs A, B, and E, H2 > 50% were regularly observed in affected gas wells for several years. At the five ETLFs, maximum CO concentrations ranged from 1400–16,000 ppmv. Like the analysis of CH4:CO2, it is hypothesized here that H2 (%):CO (ppmv) may infer the types of waste that are thermally degrading. Co-disposal of industrial wastes and MSW and the use of potentially reactive ADCs should remain an important consideration for landfill operators and regulators because of their potential long-term impacts to LFG quality.

Nigerian Industrial Revolution Plan (2014): Performance Review and Strategy for Strengthening Institutional and Regulatory Framework

Industrialization plays a key role in the development and growth of national economies. The process and economic strategy support the achievement of greater global competitiveness in the production of processed and manufactured goods by linking industrial activity with primary sector activity, domestic and foreign trade, and service activity. This is particularly true of Nigeria, where the economic structure is typically underdeveloped. The primary sector, the oil and gas sector, dominates the gross domestic product, accounting for over 95 percent of export earnings and about 85 percent of government revenue between 2011 and 2012. The industrial sector accounts for 6 percent of economic activity, while the manufacturing sector contributed only 4 percent to GDP in 2011. This explains the attempts by several administrations to evolve policies that will promote the industrialization of the country. This paper seeks to examine the performance of the Nigerian Industrial Revolution Plan (2014), with the view to recommending strategies for strengthening the institutional and regulatory framework. The data are obtained mainly from secondary sources and discussed through a content review of the literature. The study concludes and recommends the need to strengthen relevant institutions like the Central Bank of Nigeria, to promote and enhance effective industrial growth in Nigeria.

Preheating and combustion characteristics of anthracite under O2/N2, O2/CO2 and O2/CO2/H2O atmospheres

In this study, the anthracite was preheated by a circulating fluidized bed under O2/N2, O2/CO2 and O2/CO2/H2O atmospheres. And the preheating and combustion characteristics of anthracite were studied. Compared with the O2/N2 atmosphere, the structural characteristics of preheated char was improved more obviously under the O2/CO2 and O2/CO2/H2O atmospheres when the oxygen concentration was 31%, which mainly reflected in the increase of BET surface and the increase of small aromatic rings. HCN was mainly NOx precursor during the preheating under different atmospheres. In addition, a novel comprehensive evaluation of ignition and stable combustion characteristics for preheated fuel was proposed. And the minimum thermal power required for preheated char combustion and the combustion heat of preheated coal gas were main factors affecting on the ignition and stable combustion characteristics. The highest combustion efficiency of anthracite was 98.85% under the O2/N2 atmosphere (the oxygen concentrations of primary gas, secondary gas and tertiary gas were 31.0%, 36.0% and 35.0%), and the lowest NO emission in tail flue gas was 24.24 mg/MJ under the air atmosphere.

Thermal Runaway Characteristics and Gas Composition Analysis of Lithium-Ion Batteries with Different LFP and NCM Cathode Materials under Inert Atmosphere

During thermal runaway (TR), lithium-ion batteries (LIBs) produce a large amount of gas, which can cause unimaginable disasters in electric vehicles and electrochemical energy storage systems when the batteries fail and subsequently combust or explode. Therefore, to systematically analyze the post-thermal runaway characteristics of commonly used LIBs with LiFePO4 (LFP) and LiNixCoyMnzO2 (NCM) cathode materials and to maximize the in situ gas generation during battery thermal runaway, we designed experiments using an adiabatic explosion chamber (AEC) under an inert atmosphere to test LIBs. Additionally, we conducted in situ analysis of the gas components produced during thermal runaway. Our research findings indicate that after thermal runaway, NCM batteries produce more gas than LFP batteries. Based on battery gas production, the degree of harm caused by TR can be ranked as follows: NCM9 0.5 0.5 &gt; NCM811 &gt; NCM622 &gt; NCM523 &gt; LFP. The primary gas components during thermal runaway for both NCM and LFP batteries include H2,CO,CO2,C2H4, and CH4. The gas produced by LFP batteries contains a high proportion of H2. The high concentration of H2 results in a lower flammability limit (LFL) for the gas generated by LFP batteries during TR compared to the mixed gas produced by NCM batteries. Therefore, in terms of battery TR gas composition, the order of hazard level is LFP &gt; NCM811 &gt; NCM622 &gt; NCM523 &gt; NCM9 0.5 0.5 0.5. Although experimental results show that LFP batteries have superior thermal stability and lower gas production during large-scale battery thermal runaway events, considering gas generation composition and thermal runaway products, the thermal runaway risk of LFP batteries may be higher than that of NCM batteries. Although LFP batteries are considered very safe, our research results have once again drawn researchers’ attention to LFP batteries. These gases can also serve as detection signals for battery thermal runaway warnings, providing a cautionary note for the future development of electrochemical energy storage and the renewable energy sector.

The primary gas phase hydration shell of hydroxide.

The number of water molecules in hydroxide's primary hydration shell has been long debated to be three from the interpretation of experimental data and four from theoretical studies. Here, we provide direct evidence for the presence of a fourth water molecule in hydroxide's primary hydration shell from a combined study based on high-resolution cryogenic experimental photoelectron spectroscopy and high-level quantum chemical computations. Well-defined spectra of OH-(H2O)n clusters (n=2 to 5) yield accurate electron binding energies, which are, in turn, used as key signatures of the underlying molecular conformations. Although the smaller OH-(H2O)3 and OH-(H2O)4 clusters adopt close-lying conformations with similar electron binding energies that are hard to distinguish, the OH-(H2O)5 cluster clearly has a predominant conformation with a four-coordinated hydroxide binding motif, a finding that unambiguously determines the gas phase coordination number of hydroxide to be four.

Numerical and Experimental Investigations of CoNiCrAlY Particle Suspension Dynamics in Kerosene-Oxygen High Velocity Oxygen Fuel Spraying

Three-dimensional computational fluid dynamics (CFD) modelling is employed to simulate a typical high velocity oxygen fuel process (HVOF) under laboratory operating conditions. Two different modelling approaches, viz., the continuum and discrete models, are engaged to model the liquid fuel kerosene, and their influence on the resulting primary gas dynamics is investigated. Numerical results of the primary gas dynamics are validated against the available measurements and found to be in good agreement. It is observed that the fuel droplets less than 5 μm react completely inside the combustion chamber, whereas the larger droplets do not. With increasing fuel droplet size, the chemical reaction gets extended to the downstream of the combustion chamber, resulting in decreased flame temperature. Thus, it is inferred that a fuel droplet size of up to 5 μm yields better combustion characteristics. Discrete solid CoNiCrAlY particles are then injected into the high velocity primary gas stream, and their inflight dynamics are simulated. Results reveal that a maximum mean particle velocity of 700 m/s and a maximum particle temperature of 1350 K may be achieved under the given operating conditions. Particle deposit shape and size are determined both numerically and experimentally and found to be in good agreement. The influence of substrate stand-off distance on the particle deposit characteristics is investigated and reported in detail.

Compelling Heat Transfer Augmentation of Laminar Natural Convection from Vertical Plates to Binary Gas Mixtures Formed with Light Helium and Selected Heavier Gases

The present study addresses a remarkable behavior of certain binary gas mixtures in connection to laminar natural convection along a heated vertical plate at constant temperature. The binary gas mixtures are formed with light helium (He) as the primary gas and selected heavier secondary gases. The heavier secondary gases are nitrogen (N2), oxygen (O2), xenon (Xe), carbon dioxide (CO2), methane (CH4), tetrafluoromethane (CF4) and sulfur hexafluoride (SF6). The central objective in the study is to investigate the attributes of the set of seven He‒based binary gas mixtures for heat transfer enhancement with respect to the heat transfer with helium (He) and air. From heat convection theory, four thermo‒physical properties: viscosity η, density ρ, thermal conductivity λ, and isobaric heat capacity Cp affect the thermo‒buoyant convection of fluids. In this study it became necessary to construct a particular correlation equation consigned to the set of seven He‒based binary gas mixtures, which operate in the Prandtl number closed sub‒interval [0.1, 1]. The heat transfer rate with the set of seven He‒based binary gas mixtures from the vertical plate involves four thermo‒physical properties: density ρmix, viscosity ηmix, thermal conductivity λmix, and isobaric heat capacity Cp, mix that vary with the molar gas composition w. A case study is performed to elucidate the unique characteristics of the modified convective heat transport that the set of seven He‒based binary gas mixtures brings forward as compared to the convective heat transport of He and air. It was found that the He+SF6 binary gas mixture renders an absolute maximum heat transfer enhancement rate that is 39 times higher than the heat transfer rate provided by He and 78 times higher than air.

Implications of the European gas market for the long‐term construction of underground gas storage in China

AbstractUnderground gas storage (UGS) is an important part of the natural gas industry. Its peaking characteristics and storage capacity are critical to national energy supply and energy security. Compared with the mature gas market in Europe, the construction of UGSs in China faces many challenges. This study is expected to provide references for China UGS through a detailed analysis and calculations of the European natural gas market and underground storage. First, the current status and development of the European gas market were summarized. And the situation of primary energy structure, gas utilization, and UGSs construction was compared between the EU and China. Second, the working gas volume of UGSs in Europe was analyzed from the perspective of its relationship with total consumption and peak‐shaving volume. Finally, the simulation and prediction of the working curve of the energy storage facilities and the reasonable ratio of the energy storage to load were solved by the numerical fitting method. Meanwhile, the recommendations for China's natural gas market and UGSs were provided. It is appropriate to set the planning target of China UGS capacity to load at 5% of total consumption and the actual peaking gas volume will be 14.4 billion cubic meters by 2030.