Gas Formation Rate Research Articles

Alkaline water electrolysis: Ultrasonic field and hydrogen bubble formation

In alkaline water electrolysis, gas bubble coverage of the electrode surface is directly linked with an increase in cell potential. Ultrasonic field presence in water electrolysis has been proven effective in removing gas bubbles from the electrode and enhancing mass transfer and bubble removal. Most studies regarding water electrolysis under sonification focused on low-concentration NaOH electrolyte solutions so there is a lack of information regarding operating conditions similar to commercial solutions. This work focused on an experimental evaluation of the effect of an ultrasonic field with a 40 kHz frequency on water electrolysis using a lab-scale electrolyser with three different KOH solutions varying in concentration (15, 25, 35% (w/w)) at 30, 40, 50, 60 °C. A reduction in cell potential was registered across all test conditions and it was maximum for 15 and 25% KOH solutions at 30 °C with 52 and 34 mV, respectively, and decreased with an increase in temperature. For a 35% KOH solution, the cell potential reduction stayed constant across all temperatures (16–19 mV). This difference was thought to be caused by the ultrasonic frequency and power and therefore required further testing. To further investigate the effect of gas bubble accumulation on the electrode surface, measurements of hydrogen bubbles’ critical diameter were taken. It was found that a higher electrolyte concentration results in a lower critical diameter (0.404, 0.356, and 0.293 mm with a 15, 25, and 35% KOH, respectively) assumed to be a consequence of higher viscosity and gas formation rate at higher concentrations.

Subkiloparsec Scaling Relations between Hot Gas, Dense Gas, and Star Formation Rate in Five Nearby Star-forming Galaxies

Based on the newly acquired dense gas observations from the JCMT MALATANG survey and X-ray data from Chandra, we explore the correlation between hot gas and HCN J = 4 → 3 and HCO+ J = 4 → 3 emission for the first time at subkiloparsec scale of five nearby star-forming galaxies, namely M82, M83, IC 342, NGC 253, and NGC 6946. We find that both HCN J = 4 → 3 and HCO+ J = 4 → 3 line luminosity show a statistically significant correlation with the 0.5−2 keV X-ray emission of the diffuse hot gas ( L0.5−2keVgas ). The Bayesian regression analysis gives the best fit of log(L0.5−2keVgas / ergs−1)=2.39log(LHCN(4−3)′ /K km s−1 pc2) + 24.83 and log(L0.5−2keVgas / ergs−1)=2.48log(LHCO+(4−3)′ /K km s−1 pc2) + 23.84, with dispersion of ∼0.69 dex and 0.54 dex, respectively. At the subkiloparsec scale, we find that the power-law index of the L0.5−2keVgas −star formation rate (SFR) relation is log(L0.5−2keVgas/ergs−1)=1.80log(SFR/M⊙yr−1)+39.16 , deviated from previous linear relations at the global scale. This implies that the global property of hot gas significantly differs from individual resolved regions, which is influenced by the local physical conditions close to the sites of star formation.

Do spiral arms enhance star formation efficiency?

Spiral arms, as those of our own Milky Way, are some of the most spectacular features in disc galaxies. It has been argued that star formation should proceed more efficiently in spiral arms as a result of gas compression. Yet, observational studies have so far yielded contradictory results. Here, we examine arm/interarm surface density contrasts at sim 100\,pc resolution in 28 spiral galaxies from the PHANGS survey. We find that the arm AND interarm contrast in stellar mass surface density ($ is very modest, typically a few tens of percent. This is much smaller than the contrasts measured for molecular gas ($ mol $) or star formation rate ($ SFR $) surface density, which typically reach a factor of $ sim 3$. However, $ mol $ and $ SFR $ contrasts show a significant correlation with the enhancement in $ suggesting that the small stellar contrast largely dictates the stronger accumulation of gas and star formation. All these contrasts increase for grand-design spirals compared to multi-armed and flocculent systems (and for galaxies with high stellar mass). The median star formation efficiency (SFE) of the molecular gas is $16$<!PCT!> higher in spiral arms than in interarm regions, with a large scatter, and the contrast increases significantly (median SFE contrast $2.34$) for regions of particularly enhanced stellar contrast ($ contrast $>1.97$). The molecular-to-atomic gas ratio ($ mol atom $) is higher in spiral arms, pointing to a transformation of atomic to molecular gas. As a consequence, the total gas contrast ($ mol atom $) slightly drops compared to $ mol $ (median $4$<!PCT!> lower, working at sim kpc resolution), while the SFE contrast increases when we include atomic gas (median $8$<!PCT!> higher than for $ mol $). The contrasts show important fluctuations with galactocentric radius. We confirm that our results are robust against a number of effects, such as spiral mask width, tracers, resolution, and binning. In conclusion, the boost in the SFE of molecular gas in spiral arms is generally modest or absent, except for locations with exceptionally large stellar contrasts.

Galactic Magnetic Fields. I. Theoretical Model and Scaling Relations

Galactic dynamo models have generally relied on input parameters that are very challenging to constrain. We address this problem by developing a model that uses observable quantities as input: the galaxy rotation curve, the surface densities of the gas, stars and star formation rate, and the gas temperature. The model can be used to estimate parameters of the random and mean components of the magnetic field, as well as the gas scale height, root-mean-square velocity and the correlation length and time of the interstellar turbulence, in terms of the observables. We use our model to derive theoretical scaling relations for the quantities of interest, finding reasonable agreement with empirical scaling relations inferred from observation. We assess the dependence of the results on different assumptions about turbulence driving, finding that agreement with observations is improved by explicitly modeling the expansion and energetics of supernova remnants. The model is flexible enough to include alternative prescriptions for the physical processes involved, and we provide links to two open-source python programs that implement it.

Influence of oxygen concentration on torrefaction of Leucaena: gas formation rates and chemical properties analysis

Influence of oxygen concentration on torrefaction of Leucaena: gas formation rates and chemical properties analysis

E ect of temperature and absorbed dose on the rate of formation and composition of gaseous products of radiolysis of oil-bituminous rock

The results of study of gas formation at the radiation-thermal transformation of bituminous rocks of Kirmaku elds of Azerbaijan are adduced. The studies were carried out under the in uence of γ-radiation and accelerated electrons in a wide range of temperatures (20-500°C), absorbed dose (0-260 kGy), and dose rate (1 and 470 Gy/s).The in uence of temperature and adsorbed dose on the gas formation rate and content of products has been established. Estimates of technical and economic indicators of the process are given The results of these studies allow us to estimate the potential of the radiation-thermal method for producing oil products for various purposes.

The Gas Accretion Rate of Galaxies over z ≈ 0–1.3

We present here estimates of the average rates of accretion of neutral gas onto main-sequence galaxies and the conversion of atomic gas to molecular gas in these galaxies at two key epochs in galaxy evolution: (i) z ≈ 1.3–1.0, toward the end of the epoch of peak star formation activity in the Universe, and (ii) z ≈ 1–0, when the star formation activity declines by an order of magnitude. We determine the net gas accretion rate R Acc and the molecular gas formation rate R Mol by combining the relations between the stellar mass and the atomic gas mass, the molecular gas mass, and the star formation rate (SFR) at three epochs, z = 1.3, z = 1.0, and z = 0, with the assumption that galaxies evolve continuously on the star-forming main sequence. We find that, for all galaxies, R Acc is far lower than the average SFR R SFR at z ≈ 1.3–1.0; however, R Mol is similar to R SFR during this interval. Conversely, both R Mol and R Acc are significantly lower than R SFR over the later interval, z ≈ 1–0. We find that massive main-sequence galaxies had already acquired most of their present-day baryonic mass by z ≈ 1.3. At z ≈ 1.3–1.0, the rapid conversion of the existing atomic gas to molecular gas was sufficient to maintain a high average SFR, despite the low net gas accretion rate. However, at later times, the combination of the lower net gas accretion rate and the lower molecular gas formation rate leads to a decline in the fuel available for star formation and results in the observed decrease in the SFR density of the Universe over the last 8 Gyr.

A Comprehensive and Practical Method for Transformer Fault Analysis With Historical Data Trend Using Fuzzy Logic

Dissolved Gas Analysis (DGA) of transformer oil is an important tool to identify incipient faults of transformer. The challenge with the existing research on DGA is that only a single sample is used for the analysis which might lead to inaccurate results. In this paper a comprehensive three stages fuzzy logic approach is proposed to emulate best practices in the industry for transformer health analysis using the current as well as historical data from previous samples. In the first stage, a fuzzy logic is developed for an oil sampling pre-check for better lab acceptance rate which helps to save time and cost. In the second stage fuzzy, the latest IEEE Std C57.104 – 2019 is used to determine the status of transformer health by considering the gas formation rate from past samples and observing the trend. Finally, the third stage fuzzy is used to identify the transformer fault type and determine the corresponding down time. The proposed approach is tested on real data from the industry and the results demonstrate accurate transformer health identification with additional advantages of saving time and cost.

Molecular and ionized gas in tidal dwarf galaxies: the spatially resolved star formation relation

ABSTRACT Tidal dwarf galaxies (TDGs) are low-mass objects that form within tidal and/or collisional debris ejected from more massive interacting galaxies. We use CO(1–0) observations from Atacama Large Millimeter/submillimeter Array and integral-field spectroscopy from Multi-Unit Spectroscopic Explorer to study molecular and ionized gas in three TDGs: two around the collisional galaxy NGC 5291 and one in the late-stage merger NGC 7252. The CO and H α emission is more compact than the H i emission and displaced from the H i dynamical centre, so these gas phases cannot be used to study the internal dynamics of TDGs. We use CO, H i, and H α data to measure the surface densities of molecular gas (Σmol), atomic gas (Σatom), and star formation rate (ΣSFR), respectively. We confirm that TDGs follow the same spatially integrated ΣSFR–Σgas relation of regular galaxies, where Σgas = Σmol + Σatom, even though they are H i dominated. We find a more complex behaviour in terms of the spatially resolved ΣSFR–Σmol relation on subkpc scales. The majority ($\sim 60~{{\ \rm per\ cent}}$) of star-forming regions in TDGs lie on the same ΣSFR–Σmol relation of normal spiral galaxies but show a higher dispersion around the mean. The remaining fraction of star-forming regions ($\sim 40~{{\ \rm per\ cent}}$) lie in the starburst region and are associated with the formation of massive super star clusters, as shown by Hubble Space Telescope images. We conclude that the local star formation activity in TDGs proceeds in a hybrid fashion, with some regions comparable to normal spiral galaxies and others to extreme starbursts.

Star Formation and Molecular Gas Diagnostics with Mid- and Far-infrared Emission

With the start of JWST observations, mid-infrared (MIR) emission features from polycyclic aromatic hydrocarbons (PAHs), H2 rotational lines, fine structure lines from ions, and dust continuum will be widely available tracers of gas and star formation rate (SFR) in galaxies at various redshifts. Many of these tracers originate from dust and gas illuminated by UV photons from massive stars, so they generally trace both SFR and gas to varying degrees. We investigate how MIR spectral features from 5–35 μm and photometry from 3.4–250 μm correlate with SFR and molecular gas. In general, we find MIR emission features (i.e., PAHs and H2 rotational lines) trace both CO and SFR better than CO and SFR trace one another. H2 lines and PAH features correlate best with CO. Fine structure lines from ions correlate best with SFR. The [S iii] lines at 18.7 and 33.5 μm, in particular, have a very tight correlation with SFR, and we use them to calibrate new single-parameter MIR tracers of SFR that have negligible metallicity dependence in our sample. The 17 μm/7.7 μm PAH feature ratio increases as a function of CO emission which may be evidence of PAH growth or neutralization in molecular gas. The degree to which dust continuum emission traces SFR or CO varies as a function of wavelength, with continuum between 20 and 70 μm better tracing SFR, while longer wavelengths better trace CO.

Impact of Chemical and Physical Properties of Organic Solvents on the Gas and Hydrogen Formation during Laser Synthesis of Gold Nanoparticles.

Laser ablation in liquids has been established as a scalable preparation method of nanoparticles for various applications. Particularly for materials prone to oxidation, it is established to suppress oxidation by using organic solvents as a liquid medium. While this often functionalizes the nanoparticles with a carbon shell, the related chemical processes that result from laser-induced decomposition reactions of the organic solvents remain uncertain. Using a systematic series of C6 solvents complemented by n-pentane and n-heptane during the nanosecond laser ablation of gold, the present study focuses on the solvent-dependent influence on gas formation rates, nanoparticle productivity, and gas composition. Both the permanent gas and hydrogen formation was found to be linearly correlated with ablation rate, ΔHvap , and pyrolysis activation energy. Based on this, a decomposition pathway linked to pyrolysis is proposed allowing the deduction of first selection rules for solvents that influence the formation of carbon or permanent gases.

Molecular Cloud Populations in the Context of Their Host Galaxy Environments: A Multiwavelength Perspective

We present a rich, multiwavelength, multiscale database built around the PHANGS–ALMA CO (2 − 1) survey and ancillary data. We use this database to present the distributions of molecular cloud populations and subgalactic environments in 80 PHANGS galaxies, to characterize the relationship between population-averaged cloud properties and host galaxy properties, and to assess key timescales relevant to molecular cloud evolution and star formation. We show that PHANGS probes a wide range of kpc-scale gas, stellar, and star formation rate (SFR) surface densities, as well as orbital velocities and shear. The population-averaged cloud properties in each aperture correlate strongly with both local environmental properties and host galaxy global properties. Leveraging a variable selection analysis, we find that the kpc-scale surface densities of molecular gas and SFR tend to possess the most predictive power for the population-averaged cloud properties. Once their variations are controlled for, galaxy global properties contain little additional information, which implies that the apparent galaxy-to-galaxy variations in cloud populations are likely mediated by kpc-scale environmental conditions. We further estimate a suite of important timescales from our multiwavelength measurements. The cloud-scale freefall time and turbulence crossing time are ∼5–20 Myr, comparable to previous cloud lifetime estimates. The timescales for orbital motion, shearing, and cloud–cloud collisions are longer, ∼100 Myr. The molecular gas depletion time is 1–3 Gyr and shows weak to no correlations with the other timescales in our data. We publish our measurements online, and expect them to have broad utility to future studies of molecular clouds and star formation.

Differences in star formation activity between tidally triggered and isolated bars: a case study of NGC 4303 and NGC 3627

ABSTRACT Galactic bars are important drivers of galactic evolution, and yet how they impact the interstellar medium and correspondingly star formation, remains unclear. We present simulation results for two barred galaxies with different formation mechanisms, bars formed in isolation or via a tidal interaction, to consider the spatially and temporally varying trends of star formation. We focus on the early (<1 Gyr) epoch of bar formation so that the interaction is clearly identifiable. The nearby NGC 4303 (isolated) and NGC 3627 (interaction history) are selected as observational analogues to tailor these simulations. Regardless of formation mechanism, both models show similar internal dynamical features, although the interaction appears to promote bar-arm disconnection in the outer disc velocity structure. Both bars trigger similar boosts in star formation (79 per cent; 66 per cent), while the interaction also triggers an earlier 31 per cent burst. Significant morphological dependence is observed in the relation between surface gas and star formation rate. In both cases, the bar component is notably steepest; the arm is similar to the overall disc average; and the interarm clearly the shallowest. A distinguishable feature of the tidal disc is the presence of moderately dense, inefficiently star-forming gas mostly confined to tidal debris outside the optical disc. The tidal disc also exhibits a unique trend of radially increasing star formation efficiency and a clear dearth of star formation which persists along the bar between the centre and bar ends. These are potential signatures for identifying a barred system post-interaction.

Quantitative analysis of methane hydrate formation in size-varied porous media for gas storage and transportation application

Using porous media to store and transport natural gas by the hydrate method can significantly improve gas-liquid contact and increase the hydrate formation rate. Therefore, it is particularly important to understand the characteristics of hydrate formation in porous media. In this study, the formation characteristics of hydrate in porous media with different particle sizes were quantitatively investigated by low-field 1H NMR from the microscopic scale to macroscopic characteristics. The experimental results show that hydrate always tends to grow in the larger pore space area caused by the heterogeneity of the porous media, and the water conversion rate in large pores is significantly higher than that in small pores. Due to the water accumulation under the action of gravity, the distribution of hydrate shows obvious spatial heterogeneity, and the lower part is more prone to clogging. Analysis of the macroscopic characteristics of hydrate formation shows that the induction time of hydrate has no obvious relationship with the particle size of the porous media, while the formation rate and gas consumption of hydrate increase with the decrease of the particle size of porous media. The gas consumption and formation rate of hydrate in BZ01 increase by 16.85% and 174.7% respectively compared with those in BZ02/04. In addition, due to gas diffusion – hydrate film rupture – capillary force, hydrate growth has the characteristics of 2nd growth, resulting in more than 33.7% of the final gas consumption.

Discrimination of ablation, shielding, and interface layer effects on the steady-state formation of persistent bubbles under liquid flow conditions during laser synthesis of colloids

Over the past decade, laser ablation in liquids (LAL) was established as an innovative nanoparticle synthesis method obeying the principles of green chemistry. While one of the main advantages of this method is the absence of stabilizers leading to nanoparticles with “clean” ligand-free surfaces, its main disadvantage is the comparably low nanoparticle production efficiency dampening the sustainability of the method and preventing the use of laser-synthesized nanoparticles in applications that require high amounts of material. In this study, the effects of productivity-dampening entities that become particularly relevant for LAL with high repetition rate lasers, i.e., persistent bubbles or colloidal nanoparticles (NPs), on the synthesis of colloidal gold nanoparticles in different solvents are studied. Especially under batch ablation conditions in highly viscous liquids with prolonged ablation times both shielding entities are closely interconnected and need to be disentangled. By performing liquid flow-assisted nanosecond laser ablation of gold in liquids with different viscosity and nanoparticle or bubble diffusivity, it is shown that a steady-state is reached after a few seconds with fixed individual contributions of bubble- and colloid-induced shielding effects. By analyzing dimensionless numbers (i.e., Axial Peclet, Reynolds, and Schmidt) it is demonstrated how these shielding effects strongly depend on the liquid’s transport properties and the flow-induced formation of an interface layer along the target surface. In highly viscous liquids, the transport of NPs and persistent bubbles within this interface layer is strongly diffusion-controlled. This diffusion-limitation not only affects the agglomeration of the NPs but also leads to high local densities of NPs and bubbles near the target surface, shielding up to 80% of the laser power. Hence, the ablation rate does not only depend on the total amount of shielding matter in the flow channel, but also on the location of the persistent bubbles and NPs. By comparing LAL in different liquids, it is demonstrated that 30 times more gas is produced per ablated amount of substance in acetone and ethylene glycol compared to ablation in water. This finding confirms that chemical effects contribute to the liquid’s decomposition and the ablation yield as well. Furthermore, it is shown that the highest ablation efficiencies and monodisperse qualities are achieved in liquids with the lowest viscosities and gas formation rates at the highest volumetric flow rates.

Dynamical Equilibrium in the Molecular ISM in 28 Nearby Star-forming Galaxies

Abstract We compare the observed turbulent pressure in molecular gas, P turb, to the required pressure for the interstellar gas to stay in equilibrium in the gravitational potential of a galaxy, P DE. To do this, we combine arcsecond resolution CO data from PHANGS-ALMA with multiwavelength data that trace the atomic gas, stellar structure, and star formation rate (SFR) for 28 nearby star-forming galaxies. We find that P turb correlates with—but almost always exceeds—the estimated P DE on kiloparsec scales. This indicates that the molecular gas is overpressurized relative to the large-scale environment. We show that this overpressurization can be explained by the clumpy nature of molecular gas; a revised estimate of P DE on cloud scales, which accounts for molecular gas self-gravity, external gravity, and ambient pressure, agrees well with the observed P turb in galaxy disks. We also find that molecular gas with cloud-scale in our sample is more likely to be self-gravitating, whereas gas at lower pressure it appears more influenced by ambient pressure and/or external gravity. Furthermore, we show that the ratio between P turb and the observed SFR surface density, , is compatible with stellar feedback-driven momentum injection in most cases, while a subset of the regions may show evidence of turbulence driven by additional sources. The correlation between and kpc-scale P DE in galaxy disks is consistent with the expectation from self-regulated star formation models. Finally, we confirm the empirical correlation between molecular-to-atomic gas ratio and kpc-scale P DE reported in previous works.

Continuous biogas production from sugarcane as sole substrate

A German–Brazilian research project investigates sugarcane as an energy plant in anaerobic digestion for biogas production. The aim of the project is a continuous, efficient, and stable biogas process with sugarcane as the substrate. Tests are carried out in a fermenter with a volume of 10 l.In order to optimize the space–time load to achieve a stable process, a continuous process in laboratory scale has been devised. The daily feed in quantity and the harvest time of the substrate sugarcane has been varied. Analyses of the digester content were conducted twice per week to monitor the process: The ratio of inorganic carbon content to volatile organic acid content (VFA/TAC), the concentration of short-chain fatty acids, the organic dry matter, the pH value, and the total nitrogen, phosphate, and ammonium concentrations were monitored. In addition, the gas quality (the percentages of CO2, CH4, and H2) and the quantity of the produced gas were analyzed.The investigations have exhibited feasible and economical production of biogas in a continuous process with energy cane as substrate. With a daily feeding rate of 1.68 gVS /l*d the average specific gas formation rate was 0.5 m3/kgVS. The long-term study demonstrates a surprisingly fast metabolism of short-chain fatty acids. This indicates a stable and less susceptible process compared to other substrates.

Effect of porous media and its distribution on methane hydrate formation in the presence of surfactant

Hydrates are mainly stored within sediment pores in nature. Therefore, understanding their formation characteristics within the porous space is essential to the transportation of natural gas based on the hydrate-based technology. In this paper, solutions of sodium lauryl sulfate (SDS), sodium dodecyl benzene sulfonate (SDBS), and alcohol ethoxylate (AEO) were used with different-sized porous media to investigate the characteristics (gas storage capacity, formation rate, and formation distribution) of the hydrate formation. The experimental results show that the gas storage capacity was higher in the complex system composed of a small-size porous media. The improvement of hydrate formation in the complex system composed of SDS or SDBS solution was more significant than that in the AEO system which could enhance the hydrate formation. In the three complex systems, the surface of alumina particles was positively charged by hydrolysis, which resulted in a double electron layer consisting of the counter ion in the adjacent liquid phase. The anionic active groups ionized by surfactants (i.e., SDS and SDBS) were aggregated to the surface of particles under Coulomb force. This increased the content of the methane molecules by non-polar adsorption and micellar solubilization. Finally, in the complex system of SDS solution and porous media, the capillary force caused by the pores of porous media could enhance the liquid phase migration in the pores which change the distribution of hydrate formation. This work presents useful insights on the hydrate formation characteristics which are beneficial to the rapid formation of hydrate and its industrial application of both storage and transportation of natural gas in complex porous systems.

Dirt-cheap gas scaling relations: Using dust attenuation and galaxy radius to predict gas masses for large samples of AGNs

AbstractWe analyze the molecular and atomic gas data from the GALEX Arecibo SDSS Survey (xGASS) and the extended CO Legacy Database (xCOLD GASS) IRAM survey using novel survival analysis techniques to identify a small number of stellar properties that best correlate with the gas mass. We find that the dust absorption, AV, and the stellar half-light radius, R50, are likely the two best secondary parameters than improve the Kennicutt - Schmidt type relation between the gas mass and the star formation rate, SFR. We fit multiple regression, taking into account gas mass upper limits, to summarize the median, mean, and the 0.15/0.85 quantile multivariate relationships between the gas mass (atomic or molecular hydrogen), SFR, AV and/or R50. In particular, we find that the AV of both the stellar continuum and nebular gas emission shows a significant partial correlation with the molecular hydrogen after controlling for the effect of SFR. The partial correlation between the AV and the atomic gas, however, is weak and their zero-order correlation may be explained by SFR. This is expected since in poorly dust-shielded regions molecular hydrogen is dissociated by the far ultraviolet photons and HI is the dominant phase. Similarly, R50 shows significant partial correlations with both atomic and molecular gas masses. This hints at the importance of environment (e.g., galacto-centric distance) on the gas contents galaxies and on the interplay between gas and star formation rate. We apply the gas scaling relations we found to a large sample of type 2 and type 1 AGNs and infer that the gas mass correlates with AGN luminosity. This correlation is inconsistent with the prediction of AGN feedback models that strong AGNs remove or heat cold gas in their host galaxies.

Investigation of the effects of Al nanoparticles on CO2 separation from natural gas using gas hydrates

ABSTRACT The low hydrate formation rate, the low gas selectivity and the low gas storage capacity have been proved as the major bottlenecks for a successful application of CO2 capture process using gas hydrates. Aluminum nanoparticles has an important specific area, which can lead to high heat and mass transfer efficiency, large gas dissolution, fast nucleation, and formation rate. In this work, CO2-CH4 hydrate formation with and without aluminum nanoparticles was investigated. Herein, the promoting mechanism and effects of aluminum nanoparticles concentrations for an initial pressure of 4.0 MPa and temperature of 274.15 K on CO2-CH4 hydrate formation process were studied experimentally. The obtained results showed that the nanoparticles of Al, beyond a certain minimum concentration, slightly enhanced the gas dissolution, notably improved the gas consumption by crystallization and dramatically improved the gas capture selectivity. These positive effects were observed at the beginning of the process and after that became negative.