Gas Composition Research Articles

Substantiating of oil and gas prospects of Mesozoic sediments based on the geochemical model of mud volcanoes in the Shamakhi-Gobustan structural element of the South Caspian megadepression

There are up to 120 mud volcanoes in the Shamakhi-Gobustan region. During the process of mud volcano eruptions, a large amount of solid, liquid, and gaseous products are thrown to the Earth’s surface, which are widely used for the identification of oil and gas deposits and are considered the main indicator of the productivity of the basin. According to laboratory results from the analysis of solid, liquid, and gas products of mud volcanoes, it is possible to obtain detailed information about the oil-gas content of deep-lying sediments. Therefore, the study of the geochemical composition of the mud volcanoes in the Shamakhi-Gobustan trough plays a major role in the discovery of new oil-gas and gas-condensate deposits. To clarify the changes in the chemical and isotopic composition of gases from mud volcanoes in the Shamakhi-Gobustan trough and to evaluate the oil-bearing and gas-bearing potential of Mesozoic sediments, the characteristics of changes in the isotopic composition of methane gas, heavy hydrocarbons, carbon dioxide, ni- trogen, as well as CH4 and CO2, were studied. The amount of methane in the gas emissions released from mud volcanoes in the Azerbaijan region is more than 90%. The amount of CH4 in the mud volcanoes of the Shamakhi-Gobustan trough ranges from 78.5% to 97.56%. The minimum amount of methane is found in North Gobustan (Gizmeydan 86.8%, Malikchobanli 78.5%), while relatively high amounts are mainly noted in Central (Kushchu 97.55%) and South Gobustan (including Dashgil 97.57%, Goturdag 96.55%, Bahar 96.78%). Mud vol- canoes are less developed in the North Gobustan region and are small in size. In the Central zone, both the size and the number of volcanic cones increase significantly compared to North Gobustan. The largest and most active volcanoes have developed in the southern zone of the trough. Huge mud volcanoes such as Dashmerdan, Solakhay, Ayrantoken, Goturdag, Kirdag, and other volcanoes have developed along the Alat range. The mud volcanoes of North and Central Gobustan are mainly confined to Cretaceous and Paleogene sediments, and due to the low occurrence of plastic clay rocks in these sediment sections, mud volcanoes are rare and weakly active. On the contrary, to the south of these zones, that is, in South Gobustan, they are located in Pliocene sediments, and due to the presence of very thick plastic rocks in their section, mud volcanoes are widespread, and they are active volcanoes that are morphologically sharply reflected. It should be noted that in areas where plastic clay rocks with significant thickness and rheologically active properties are developed, large cones of mud volcanoes that erupt frequently are observed. The calculated gas production of mud volcanoes increases from the northern zone towards South Gobustan. Thus, while the calculated gas production of the Nabur volcano located in the Northern zone is 1500 m3/day, the calculated gas production of the Dashgil mud volcano located in South-Eastern Gobustan is 40,000 m3/day. In the central and south- ern zones of the Shamakhi-Gobustan trough, the presence of ancient rock fragments from the Oligocene-Miocene (Maykop) age rocks forming their roots in the solid waste of mud volcanoes (Cretaceous, Paleocene, Eocene), a large percentage of methane gas (97.57%), transverse elevations, and the presence of an intersection zone of longitudinal faults suggests that there is a tectonic rupture zone rich in natural gas below the base of the volcano. This is proven once again by the occurrence of gas flows in Anart (110,000 m3/day), Utalgi (50,000 m3/day), and the Touragay field (20,000 m3/day). The presence of oil films in the eruption products of mud volcanoes indicates the accumulation of oil alongside gas.

Novel Synthesis of Zinc Oxide on Cotton Fabric by Cathodic Cage Plasma Deposition for Photocatalytic and Antibacterial Performance.

Cotton fabrics with zinc oxide (ZnO) coating are of significant interest due to their excellent antibacterial performance. Thus, they are widely in demand in the textile industry due to their medical and hygienic properties. However, conventional techniques used to deposit ZnO on fabric require long processing times in deposition, complex and expensive equipment, and multiple steps for deposition, such as a separate process for nanoparticle synthesis and subsequent deposition on fabric. In this study, we proposed a new method for the deposition of ZnO on fabric, using cathodic cage plasma deposition (CCPD), which is commonly used for coating deposition on conductor materials and is not widely used for fabric due to the temperature sensitivity of the fabric. The effect of gas composition, including argon and a hydrogen-argon mixture, on the properties of ZnO deposition is investigated. The deposited samples are characterized by XRD, SEM, EDS, photocatalytic, and antibacterial performance against Staphylococcus aureus and Pseudomonas aeruginosa bacteria. It is observed that ZnO-deposited cotton fabric exhibits excellent photocatalytic degradation of methylene blue and antibacterial performance, specifically when a hydrogen-argon mixture is used in CCPD. The results demonstrate that CCPD can be used effectively for ZnO deposition on cotton fabric; this system is already used in industrial-scale applications and is thus expected to be of significant interest to garment manufacturers and hospitals.

Simulation of mode transitions in capacitively coupled Ar/O2 plasmas

In this work, the effects of the frequency, pressure, gas composition, and secondary-electron emission coefficient on the discharge mode in capacitively coupled Ar/O2 plasmas were carefully studied through simulations. Three discharge modes, i.e., α, γ, and drift-ambipolar (DA), were considered in this study. The results show that a mode transition from the γ-DA hybrid mode dominated by the γ mode to the DA-α hybrid mode dominated by the DA mode is induced by increasing the frequency from 100 kHz to 40 MHz. Furthermore, the electron temperature decreases with increasing frequency, while the plasma density first decreases and then increases. It was found that the electronegativity increases slightly with increasing pressure in the low-frequency region, and it increases notably with increasing pressure in the high-frequency region. It was also observed that the frequency corresponding to the mode transition from γ to DA decreased when the secondary-electron emission coefficient was decreased. Finally, it was found that increasing the oxygen content weakens the γ mode and enhances the DA mode. More importantly, the density of oxygen atoms and ozone will increase greatly with increasing oxygen content, which is of great significance for industrial applications.

Influence of Water Vapor and Local Gas Velocity on the Oxidation Kinetics of In625 at 900 °C: Experimental Study and CFD Gas Phase Simulation

AbstractThe effect of water vapor content on the oxidation behavior of In625 at 900 °C in synthetic air was reported. The higher the water vapor content, the greater the oxidation and volatilization rates were. Increasing the water vapor content led to an increase in the proportion of spinel and rutile-type oxides in the oxide scale compared to chromia, and the proportion of Al-rich oxides within the alloy. A kp-kv mass variation model was used to quantify the experimental results, and Fluent Ansys® CFD simulations of the gas phase were used to predict volatilization rates. CFD simulations were used to calculate local gas velocity, temperature and composition along with local volatilization rates at each point on the sample surface. It was possible to explain not only the variations in volatilization between upstream and downstream samples, but also the increased volatilization at sample corners. For longer durations, it was shown experimentally that the rate of volatilization decreases. This was explained by the enrichment of the oxide scale with spinel and rutile-type oxides.

Experimental study on co-gasification of cellulose and high-density polyethylene with CO2

Co-gasification of biomass and waste plastic with CO2 presents an effective strategy for integrating biomass conversion, waste utilization and carbon recycling. In this study, the co-gasification of cellulose and high-density polyethylene with CO2 was investigated experimentally. The effects of mixing ratio and temperature on co-gasification characteristics, including gas yield, product gas composition, lower heating value of syngas and gasification efficiency, were comprehensively evaluated. Additionally, the interaction between cellulose and high-density polyethylene was analyzed. The results suggested that increasing the polyethylene content in feedstock resulted in decreased yields of H2 and CO, increased CH4 yield, increased lower heating value of syngas and reduced gasification efficiency. The interaction between cellulose and high-density polyethylene enhanced the gas yield, with the most significant effect at 40 % polyethylene content. In the range of 900 °C–1000 °C, increasing the temperature resulted in increased gas yield, reduced lower heating value of syngas and increased gasification efficiency. The positive interaction between cellulose and high-density polyethylene on gas yield was more significant at higher temperatures. This work shed light on reaction characteristics for co-gasification of biomass and high-density polyethylene with CO2, laying the foundation for the design and application of this technology.

Fundamental mechanism and potential optimization methods for the overpressure phenomenon of Novec 1230 and 2-BTP

Novec 1230 (C6F12O) and 2-BTP (C3H2BrF3) created higher peak pressures (overpressure phenomenon) than with no agent in the aerosol can test of Federal Aviation Administration. Previous researches ascribed the overpressure to the fuel-like property of 2-BTP and Novec 1230. However, the fundamental cause of the overpressure phenomenon has not been fully clarified, and no solution has been proposed to improve the inhibition effect and reduce the combustion enhancement of 2-BTP and Novec 1230. For accelerating the development process of halon replacement in aircraft cargo bay, this work in-depth studied the fundamental mechanism of the overpressure phenomenon of two agents. Novec 1230 consumes O2 at low loading from the reactions of fluorine-containing groups such as C3F7 with chain branching reactions, and further produces a large amount CO and HF. Different from Novec 1230, 2-BTP does not directly consume O2, however induces a higher concentration of H radical at high loading and further promote the reaction rate of H + O2OH+O to consume large quantities of O2. In addition, the calculated pressure and the sum of the equilibrium gas composition were studied to find that 2-BTP and Novec 1230 greatly increase the total gas content, resulting in much higher pressure rise than Halon 1301. Additionally, the recommended measures of 2-BTP and Novec 1230 to improve the reduce the overpressure were proposed based on their combustion inhibition and enhancement mechanism.

Reactive Gas Cluster Ion Beams for Enhanced Drug Analysis by Secondary Ion Mass Spectrometry.

In this study, we investigate the formation and composition of Gas Cluster Ion Beams (GCIBs) and their application in Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) analysis. We focus on altering the carrier gas composition, leading to the formation of (Ar/CO2)n or (H2O)n GCIBs. Our results demonstrate that the addition of a reactive species (CO2) to water GCIBs significantly enhances the secondary ion yield of small pharmaceutical compounds in the positive ion mode. In negative ion mode, the addition of CO2 resulted in either a positive enhancement or no effect, depending on the sample. However, an excess of CO2 in the carrier gas leads to the formation of carbon dioxide clusters, resulting in reduced yields compared to that of water cluster beams. Cluster size also plays a crucial role in overall yields. In a simple two-drug system, CO2-doped water clusters prove effective in mitigating matrix effects in positive ion mode compared to pure water cluster, while in negative ion mode, this effect is limited. These clusters are also applied to the analysis of drugs in a biological matrix, leading to more quantitative measurements as shown by a better fitting calibration curve. Overall, the doping of water clusters with small amounts of a reactive gas demonstrates promising benefits for higher sensitivity, higher resolution molecular analysis, and imaging using ToF-SIMS. The effectiveness of these reactive cluster beams varies depending on the experimental parameters and sample type.

An Active and Regenerable Nanometric High‐Entropy Catalyst for Efficient Propane Dehydrogenation

AbstractPropane dehydrogenation (PDH) is crucial for propylene production, but commercially employed Pt‐based catalysts face susceptibility to deactivation due to the Pt sintering during reaction and regeneration steps. Here, we report a SiO2 supported nanometric (MnCoCuZnPt) high‐entropy PDH catalyst with high activity and stability. The catalyst exhibited a super high propane conversion of 56.6 % with 94 % selectivity of propylene at 600 °C. The propylene productivity reached 68.5 molC3H6 ⋅ gPt−1 ⋅ h−1, nearly three times that of Pt/SiO2 (23.5 molC3H6 ⋅ gPt−1 ⋅ h−1) under a weight hourly space velocity of 60 h−1. In a high‐entropy nanoparticle, Pt atoms were atomically dispersed through coordination with other metals and exhibited a positive charge, thereby showcasing remarkable catalytic activity. The high‐entropy effect contributes to the catalyst a superior stability with a low deactivation constant of 0.0004 h−1 during 200 hours of reaction under the industrial gas composition at 550 °C. Such high‐entropy PDH catalyst is easy regenerated through simple air combustion of deposited coke. After the fourth consecutive regeneration cycle, satisfactory catalytic stability was observed, and the element distribution of spent catalysts almost returned to their initial state, with no detectable Pt sintering. This work provides new insights into designing active, stable, and regenerable novel PDH catalysts.

Joule-Thomson expansion for charged-AdS black hole with nonlinear electrodynamics and thermal fluctuations by using Barrow entropy

This paper investigates the complex interplay between charged anti-de Sitter black hole thermodynamic behavior and nonlinear electrodynamics. Strong insights are obtained by examining the impact of nonlinear electrodynamics on the Joule-Thomson expansion of charged black holes and assessing the thermal fluctuations with higher-order corrections in the context of Barrow entropy. The research shows the complex interactions influencing thermal properties from Joule-Thomson coefficients are affected by temperature, pressure, and changes in gas composition due to the effects of charges and nonlinear electrodynamics factors on inversion temperature and pressure. Furthermore, analyzing black hole isenthalpic curves provides important insights into the thermodynamic behavior of the system by highlighting discrete heating and cooling zones in the inversion curve. Significant effects of nonlinear dynamics on the thermodynamic parameters of the system are highlighted by the notable variations in the Helmholtz free energy, internal energy, enthalpy, and Gibbs free energy of charged anti-de Sitter black holes. By demonstrating the complex and captivating nature of these interactions, the paper concludes by emphasizing the significant influence of nonlinear dynamics on the thermodynamic parameters of charged black holes within the framework of Barrow entropy.

Monitoring CO 2 , CO and CH 4 , impacted or not by ventilation and anthropogenic activities, in the galleries of the Underground Research Laboratory (URL) of Meuse/Haute-Marne

The alternation between periods of ventilation and non-ventilation of the galleries in the Meuse/Haute-Marne Underground Research Laboratory (URL) within the Callovo-Oxfordian argillaceous rock affects the content of CO 2 , CO and CH 4 in atmospheric air. Monitoring the evolution of the gas composition in the galleries was conducted over a period of about 4 months. Two models of infrared laser spectroscope (Picarro) were used, one to measure CO 2 , CO, and CH 4 concentrations and the other to measure CH 4 isotopic compositions. The results show a night/day periodicity with the highest concentrations at nighttime and the lowest during the daytime in the URL. Long-term monitoring of these gases at the surface shows the same evolution, but with different amplitudes. Moreover, in the URL, a weekday, weekend/holiday periodicity superimposed. The concentrations of CO 2 in the galleries are influenced by human activities and ventilation. During working days, the galleries are ventilated, and human activities increase the CO 2 concentrations. Conversely, during weekends and holidays, CO 2 concentrations decrease due to the cessation of ventilation and human activities, and consumption of CO 2 by concrete carbonation. The data analysis confirms CH 4 source coming from the rock and reveals compelling evidence of CO sources that are likely originating from rock and/or gallery engineered structure materials. Despite the difficulties in quantifying local sources and sinks of these gases, this study demonstrates the feasibility of obtaining valuable insights into their variability. This study provides information on potential sources and sinks of CO 2 , CO, and CH 4 in this context.

Numerical Analysis of Hydrogen-Enriched Natural Gas on Combustion and Emission Characteristics

AbstractThe integration of hydrogen into natural gas infrastructure presents a viable strategy for mitigating greenhouse gas emissions and advancing toward carbon neutrality. This study investigates the combustion characteristics and emissions profiles of hydrogen-enriched natural gas mixtures, specifically focusing on the composition of Russian pipeline natural gas. A comprehensive mathematical model was developed to predict emission concentrations and simulate fuel mixture combustion using MATLAB Simulink software. This versatile model facilitates further analysis within the MATLAB ecosystem. The simulation results demonstrate a significant correlation between the hydrogen content in the natural gas mixture and the resulting heat power output. With a constant fuel consumption rate, a notable decrease in heat power was observed as the hydrogen concentration increased, reaching a maximum reduction of 44.9% at a 45% hydrogen content. These findings underscore the feasibility of partially substituting natural gas with hydrogen, while also highlighting the necessity for increased fuel flow rates to maintain equivalent power output levels. This poses additional challenges for natural gas grid operators, necessitating infrastructure adaptations to accommodate higher fuel demands. The insights gained from this research contribute to the growing body of knowledge surrounding hydrogen integration in the energy sector, offering valuable implications for decarbonization strategies and the optimization of natural gas infrastructure.

Advanced soil-gas geochemical exploration methods for orogenic gold deposits: A case study of Chalapu deposit, Xizang

Orogenic gold deposits play a significant role in the world’s gold reserves, and their distinctive characteristics pose challenges for exploration. The low sulfide content and narrow, fault-controlled sulfide-quartz veins hinder the use of traditional mineral exploration methods to locate deeply buried ore bodies, particularly in regolith-covered areas. Enhanced methods are required to detect deposits at greater depths. Soil gas composition shows promising potential for mineral exploration by conveying information about sulfur-rich and carbon-rich gases related to deep-seated mineralization into surface soils. However, the prospects of this method for gold deposits remain uncertain. In this study, a novel method was introduced to perform an integrated H2S, SO2, CH4, and CO2 soil-gas geochemical survey on gold ore bodies of different scales at the Chalapu deposit in Tibet. The results unveiled notable gas geochemical anomalies of H2S, SO2, CH4, and CO2 above the multi-layered or thick gold ore bodies. For instance, on exploration line 16 at point A1607, H2S reached the regional maximum value of 1.064 ppm, coinciding with the surface exposure of the thickest gold ore body, measuring 19.81 m. While the presence of CH4 and CO2 anomalies alone may not signify potential mineralized zones, the combined presence of anomalous H2S and SO2 values along with CH4 and CO2 concentrations appears to be effective in identifying mineralization. These combinations of geochemical anomalies not only uncover concealed ore bodies, but also delineate the trend and extension direction in strike and dip of ore bodies. Gas intensity may provide insights into the scale of the ore bodies, with stronger gas anomalies observed in areas with thicker ore bodies at similar depths. Thus, the study reveals that soil-gas exploration shows great promise as an exploration technique for orogenic gold deposits, especially in areas with regolith cover hindering traditional methods from detecting mineralized zones for gold exploration.

EXPERIMENTAL STUDY OF HYDRATE FORMATION PECULIARITIES FOR CONDITIONS OF THE TURNO AND CENOMANIAN DEPOSITS: Part II

This paper is the second part of the research devoted to the study of hydrate formation features for the conditions of Turonian and Cenomanian deposits. The launch of new gas projects at the Turon and Senoman production facilities in Western Siberia provided a good opportunity to critically analyze the known methods of protecting production, gathering and transportation facilities of the gas field from the formation of solid gas hydrates. The paper presents the experience of implementing a program of laboratory studies of conditions of gas hydrate formation with their subsequent processing and in-depth analysis. The research program covered the area of thermobaric parameters typical for the conditions of Turon-Senoman deposits exploitation with localization of hydrate-hazardous areas in the conditions of Technological Regimes for full development. The description of laboratory studies is given, in which two gas compositions of Senoman and Turon objects, different variants of mineralization and ionic composition corresponding to formation and condensation water, as well as hydrate formation conditions under changing dosages of basic inhibitor on the basis of methanol were considered. The details of the experiment based on the method of swinging cells and the subsequent analysis of the results of the completed experiments to determine the thermobaric conditions of formation and decomposition of hydrates are given. The main features of the experiment are specified, estimates of the rate of change of the influencing parameters of the experiment on its quality are given. In the process of implementation of the experimental program, the optimal values of these parameters were selected, which allowed us to significantly reduce the variation of experimental results to determine the thermobaric conditions of hydrate formation. It is experimentally established that the temperature of hydrate decomposition is higher than the temperature of its formation at all investigated gas compositions and water mineralization.

CFD Modelling and Optimization of Solid Waste Combustion in a 1 MW Fixed Bed Combustion Chamber

The global population and energy consumption grow each year. Therefore, the tendency to use biofuels instead of fossil fuels assist the global requirement. Also, enhancing of the combustion efficiency and minimizing pollutant emissions during the combustion of municipal solid waste (MSW). The present study employed a CFD model to simulate solid fuel combustion in a grate combustion chamber which was commonly used in small-capacity boilers. computational fluid dynamics technique was used to simulate complex solid fuel reactions where 1 MW boiler was supposed for wood and coal combustion. The achievements found that 10%-dried MSW was used as fuel. The results of the study were related to the average gas flow temperatures and composition in the furnace outflow section, as well as the high combustion temperatures of fossil fuels. The results for the average temperature and average chemical molecular fractions (CO, O2, CO2, H2O, and N2) generated at the exit of the combustion process were positive. Thus, it was found that the thermal efficiency of the boiler was significantly affected by the amount of air supplied to the system at a temperature of 273 K and atmospheric pressure. We observed variations in flame morphology, temperature profiles, and corresponding numerical values.

Recognition of Artificial Gases Formed during Drill-Bit Metamorphism Using Advanced Mud Gas

Drill-bit metamorphism (DBM) is the process of thermal degradation of drilling fluid at the interface of the bit and rock due to the overheating of the bit. The heat generated by the drill when drilling into a rock formation promotes the generation of artificial hydrocarbon and non-hydrocarbon gas, changing the composition of the gas. The objective of this work is to recognize and evaluate artificial gases originating from DBM in wells targeting oil accumulations in pre-salt carbonates in the Santos Basin, Brazil. For the evaluation, chromatographic data from advanced mud gas equipment, drilling parameters, drill type, and lithology were used. The molar concentrations of gases and gas ratios (especially ethene/ethene+ethane and dryness) were analyzed, which identified the occurrence of DBM. DBM is most severe when wells penetrate igneous and carbonate rocks with diamond-impregnated drill bits. The rate of penetration, weight on bit, and rotation per minute were evaluated together with gas data but did not present good correlations to assist in identifying DBM. The depth intervals over which artificial gases formed during DBM are recognized should not be used to infer pay zones or predict the composition and properties of reservoir fluids because the gas composition is completely changed.

Regulating gas transmission rates in microperforated polybutylene succinate films for modified atmosphere packaging of bananas

Carbon dioxide (CO2) laser technology was used to modify the gas permeability of polybutylene succinate (PBS) film by creating holes. The holes were made using pulse fluences ranging from 37.0 to 369.8 J cm−2 and pulse lengths varying from 20 to 200 µs. The minimum fluence required to cause deformation in the PBS film was 129.4 J cm−2, resulting in a tiny opening at the perforation site. Aperture size and pulse duration have an impact on gas exchange because they increase the surface area of microholes and facilitate gas transfer. The efficacy of banana packing was evaluated by employing microperforated PBS films with different number of holes and a pulse length of 200 µs. The lowest CO2 and highest oxygen (O2) concentrations were observed in PBS 7/200, followed by 5/200, 3/200, and 1/200, respectively. The gas composition with the highest potential was PBS 7/200, indicating its effectiveness in preserving banana quality. Perforating PBS film packaging with a CO2 laser allows for regulated gas permeability, which has the potential to improve the quality and safety of food.

Experimental studies of H2/Ar plasma in a cylindrical inductive discharge with an expansion region

Abstract The electrical parameters of H2/Ar plasma in a cylindrical inductive discharge with an expansion region are investigated by a Langmuir probe, where Ar fractions range from 0% to 100%. The influence of gas composition and pressure on electron density, the effective electron temperature and the electron energy probability functions (EEPFs) at different spatial positions are present. In driver region, with the introduction of a small amount of Ar at 0.3 Pa, there is a rapid increase in electron density accompanied by a decrease in the effective electron temperature. Additionally, the shape of the EEPF transitions from a three-temperature distribution to a bi-Maxwellian distribution due to an increase in electron–electron collision. However, this phenomenon resulting from the changes in gas composition vanishes at 5 Pa due to the prior depletion of energetic electrons caused by the increase in pressure during hydrogen discharge. The EEPFs for the total energy in expansion region is coincident to these in the driver region at 0.3 Pa, as do the patterns of electron density variation between these two regions for differing Ar fractions. At 5 Pa, as the discharge transitions from H2 to Ar, the EEPFs evolved from a bi-Maxwellian distribution with pronounced low energy electrons to a Maxwellian distribution in expansion region. This evolve may be attributed to a reduction in molecular vibrational excitation reactions of electrons during transport and the transition from localized electron dynamics in hydrogen discharge to non-localized electron dynamics in argon discharge. In order to validate the experimental results, we use the COMSOL simulation software to calculate electrical parameters under the same conditions. The evolution and spatial distribution of the electrical parameters of the simulation results agree well with the trend of the experimental results.

Influence of different factors on gap breakdown process with hot electrode and high temperature gas medium in low voltage circuit breaker chamber based on particle-in-cell/Monte-Carlo collision simulation

Different factors such as gas composition inside the low voltage circuit breaker (LVCB) chamber and the residual plasma in the post-arc stage affect the breakdown process, which in turn affects the breaking capacity of LVCBs. In this paper, the effects of non-parallel electrode structure, gas temperature and pressure, electrode temperature, and gap distance on gap breakdown of hot electrode under high temperature gas conditions were studied, for which a particle-in-cell/Monte-Carlo collision simulation model has been established, which takes into account the effects of high-temperature gas components, cathode electron thermal emission, electron collision ionization and other effects, and simulation studies have been conducted. The simulation results show that the increase in gap gas temperature, the decrease in air pressure, and the increase in electrode temperature will lead to the gap breakdown more easily. With the increase in the gap length, the breakdown voltage increases, but the average electric field intensity required for breakdown decreases. In the non-parallel electrode structure, the breakdown occurs first at the position with the shortest gap distance, then the cathode sheath forms and extends along the electrode surface to other areas, and finally, the entire gap breaks down.

Gas Composition of Fluids That Formed Ore Deposits over Geological Time: from the Archean through Cenozoic

Gas Composition of Fluids That Formed Ore Deposits over Geological Time: from the Archean through Cenozoic

Anode potential regulates gas composition and microbiome in anaerobic electrochemical digestion

Anaerobic electrochemical digestion (AED) is an effective system for recovering biogas from organic wastes. However, the effects of different anode potentials on anaerobic activated sludge remain unclear. This study confirmed that biofilms exhibited the best electroactivity at −0.2 V (vs. Ag/AgCl) compared to −0.4 V and 0 V. Gas was further regulated, with the highest hydrogen content (47 ± 7 %) observed at −0.2 V. The 0 V system produced the largest amount of methane (70 ± 8 %) and exhibited the greatest presence of hydrogen-utilizing microorganisms. The gas yield at −0.4 V was the lowest, with no hydrogen detected. Excess bioelectrohydrogen at −0.2 V and 0 V caused the co-enrichment of Methanobacterium and Acetoanaerobium, establishing a thermodynamically feasible current-acetate-hydrogen electron cycle to improve electrogenesis. These results provide insights into the regulatory strategies of MEC technology during anaerobic digestion, which play a decisive role in determining the composition of biogas.