Gas Accumulation Research Articles

Study on Development Characteristics and Reservoir Formation Model of Lower Ordovician Reservoirs in Central Sichuan

Sichuan Basin is a large superimposed petroliferous basin, which has experienced multi-stage extension-convergence cycle and has great potential of oil and gas resources. In recent years, the lower combination oil and gas exploration in the middle Sichuan area has made great breakthroughs in the Sinian Dengying Formation and the Lower Cambrian Longwangmiao Formation, but has not achieved good results in the Ordovician. At present, a number of Wells in the middle Sichuan area show varying degrees of oil and gas in the Lower Ordovician strata, suggesting that the Ordovician strata in this area have the basic conditions for the formation of large-scale oil and gas reservoirs. However, no consensus has been reached on the paleogeographic pattern of Ordovician lithofacies and the distribution of favorable facies zones in this area, and the understanding of reservoir types and reservoir properties is quite different. Therefore, the weak basic research on the geological conditions of reservoir formation has severely restricted the hydrocarbon exploration of the Ordovician in this area. In this paper, the Lower Ordovician lithofacies paleogeography reconstruction and reservoir characteristics analysis are carried out by systematically combing the drilling and field profile data in the central Sichuan area, combined with core observation, thin section identification and reservoir analysis, and finally the Ordovician oil and gas accumulation model is established. The results show that the lithofacies paleogeography distribution of the Lower Ordovician Tongzi-Honghuayuanstage in the central Sichuan area is from the paleo-uplift to the east in the order of platform tidal flat to platform shoal to limited platform. The Lower Ordovician reservoir types in the middle Sichuan area include karst reservoir and dolomite reservoir, among which the karst reservoir is heavily filled and the reservoir performance is limited. The Ordovician reservoir-forming model in the middle Sichuan area reveals a new exploration model of dolomite superimposed bedding under karst in the epicontinental platform, which provides important geological basis for the new breakthrough of Ordovician oil and gas exploration.

Acute Fatal Gastric Dilatation and Volvulus in a Captive Adult Linnaeus’s Two-Toed Sloth (Choloepus didactylus) in Amazon Biome

This study aims to report the dietary and daily management, clinical signs, complementary exams, and pathological findings related to an acute and fatal case of gastric dilatation and volvulus (GDV) in a captive Linnaeus’s two-toed sloth (Choloepus didactylus) in the Amazon Biome. An adult female sloth, rescued after being electrocuted, was housed at the Wildlife Section of the Veterinary Hospital (WSVH) of the Institute of Veterinary Medicine (IVM) at the Universidade Federal do Pará (UFPA). It was fed a diverse diet that included animal protein, fruits, vegetables, and greens, with vitamin and mineral supplementation. After five years, the sloth was found in its enclosure hyporesponsive, dehydrated, hypothermic, and hyperventilating, with an abdominal dilation of firm consistency. During emergency care, the animal died. Fecal samples collected two days before death were positive only for Clostridium perfringens type A. Necropsy findings included dilatation of the squamous gastric compartment due to gas accumulation, with necrotic and hemorrhagic mucosa, a 180–270° volvulus obstructing the gastroesophageal region, and intestinal mucosal hyperemia. Histopathology revealed marked congestion with hemorrhage and gastric mucosal necrosis, along with tertiary lymphoid follicles in the submucosa. To the authors’ knowledge, this is the first report of GDV in a sloth in Brazil. Further research is needed to develop appropriate approaches to GDV in captive sloths.

Effect of acids produced by the dissolution of sulfur and nitrogen oxides in the performance of MEA solvent in CO2 capture: Experimental results and modeling

Solvent-based CO2 capture is very important for the mitigation of greenhouse gases. The presence of SO2 and NO2 is observed in several types of CO2-containing industrial flue gases and even small concentrations can cause significant changes in the performance of the solvent. Their effects on the CO2 solubility have received very little attention. To simulate the effect of dissolution and accumulation of SO2 and NO2 acid gases on the CO2 loading of aqueous ethanolamine (MEA) solutions, H2SO4 and HNO3 were added, as sources of NO3− and SO4−2 anions, respectively. The CO2 solubility in 30% wt. aqueous MEA solutions containing 2.9% wt. H2SO4 with and without 1.8% wt. HNO3 was experimentally measured using a pressure decay method at 313, 333 and 353 K and approximately 5-500 kPa. In both cases, it is revealed that the addition of H2SO4 and HNO3 substantially decreases the CO2 solubility. In addition, the modified Kent-Eisenberg model was used to predict the CO2 solubility in all systems and at all the studied conditions. The model predictions are in satisfactory agreement with the experimental data presenting Average Absolute Deviations between 4.8 and 6.8 % in all cases.

Development and validation of hydrophobic molded pulp nursery pots made of hemp hurd

Biodegradable nursery pots (BNPs) composed of 50 % hemp hurd and 50 % recycled cardboard fibers (w/w dry basis) were produced using a custom-built handheld molded pulp device. Milling followed by sequential peracetic acid and sodium hydroxide delignification treatment reduced lignin content of hemp hurd from 23.76 % to 2.39 %, liberating cellulose and hemicellulose fibers for enabling the formation of interfiber interactions in molded pulp formulations. Beeswax and precipitated calcium carbonate based hydrophobic coating at ~10 μm thickness significantly enhanced hydrophobicity of the BNPs, as indicated by the surface contact and sliding angle of 116.25° and 34.82°, respectively. Anaerobic biodegradability of BNP was confirmed via carbon dioxide and methane gas accumulation measurements. Developed BNPs were successfully validated through an eleven week greenhouse planting trial. This study introduced a new biodegradable molded pulp formulation made from hemp hurd and validated its application as an alternative to single use plastic nursery pots for growing seedlings.

Natural gas accumulation and modification in the Precambrian carbonate reservoirs of the southwestern Sichuan Basin, China: Insight from pore fluid overpressure reconstruction and simulation

Natural gas accumulation and modification in the Precambrian carbonate reservoirs of the southwestern Sichuan Basin, China: Insight from pore fluid overpressure reconstruction and simulation

Nucleus of M31: Upper limits to the molecular and ionised gas content

We report observations performed with the NOrthern Extended Millimeter Array (NOEMA) and Atacama Large Millimeter/submillimeter Array (ALMA) of the nucleus of Andromeda (M31) that place strong constraints on the presence of gas in the cold or warm phase. M31 hosts the largest supermassive black hole (SMBH) closer than 1\,Mpc to us. Its nucleus is silent, with some murmurs at the level of $ 4 L_ Edd $, and it is surrounded by a disc of old stars with a radius of 5pc. The mass loss from these stars is expected to fill a molecular gas disc within the tidal truncation of 1 pc ($=0.26$\,arcsec) of 10$^4 M_ corresponding to a CO(1-0) signal of 2\,mJy with a line width of 1000 km/s. We observed the nucleus with NOEMA in CO(2-1) and with ALMA in CO(3-2) with angular resolutions of $0.5$ (1.9 pc) and $0.12$ (0.46 pc), respectively. We exclude the presence of molecular gas with an upper limit of 3sigma on the $H_2$ mass of 195$M_ based on CO(3-2) ALMA observations . The CO(3-2) upper limit also constrains warm gas, which escapes detection in CO(1-0). The scenario of cold gas accumulation next to the nucleus of M31 that originates from mass loss of the old stellar population is not verified and excluded at a level of 150$ sigma . The hot gas expelled by the stellar winds might instead never cool or fall onto the disc. Alternatively, the mass-loss rate of the stellar wind may have been overestimated by a factor $50$, and/or the ionised gas has escaped from the nucleus. The SMBH in M31 clearly is in a low activity state similar to what is observed for Sgr A* in the Milky Way (MW). Recently, a cool (10$^4$ K) ionised accretion disc has been detected around Sgr A* in the H30alpha recombination line with ALMA. If the sizes, masses, and fluxes were rescaled according to the mass of the black hole of M31 (35 times higher than in the MW) and its distance (97 times further away than in the MW), a similar disc might easily be detectable around the nucleus of M31. The expected signal would be eight times weaker that the signal detected in SgrA*. We searched for an ionised gas disc around the nucleus of M31 with NOEMA, and we place a 3sigma upper limit on the H30alpha recombination line at a level twice lower than expected with a simple scaling of the SgrA*.

GEOLOGICAL CONDITIONS OF FORMATION AND DISTRIBUTION OF GAS-GEOCHEMICAL FIELDS IN BOTTOM SEDIMENTS OF THE LAPTEV-SIBERIAN SEA ZONE OF THE EAST ARCTIC SHELF

Gas composition of bottom sediments of the Laptev-Siberian Sea geostructural zone (LSZ) was determined to include: helium and hydrogen in concentrations of 0.0028–0.2092 and 0.0012–0.8727 cm3/kg, hydrogen sulfide – 0.0006–0.0072, carbon monoxide – 0.0016–0.0577, carbon dioxide – 0.1482–21.1602, methane – 0.0017–8.3047 and its homologues (in total) – 0.00001–0.0355 cm3/kg. It was found that the values of average concentrations of gases in bottom sediments increase with the depth of their occurrence and exceed the anomaly criteria identified for the East Arctic shelf by 2.6–27.7 times, including: CO2, CO and H2S – by 2.6, 3.0 and 3.4 times, ΣC2–C5 and He – by 9.3 and 10.8 times, CH4 – by 27.7 times; this actually indicates a high degree of gas saturation of bottom sediments of the region. The formation of CO2, CO, H2S, H2, CH4 and ΣC2–C5 anomalies in sediments of the upper and the base of the middle sampling horizon is determined by relatively high contents of sapropelic and humic organic matter and gas influx from the lower horizon. Distribution of anomalies with maximum concentrations of natural gases and He in sediments of the lower horizon, with minimum contents of Corg, is associated with zones of faults, large dislocations, tectono-magmatic and seismic activity, which are the main routes of diffusion-migration of gas transfer to bottom sediments. Formation of concentrations of gases and their anomalies in sediments of the LSZ follows the rules of additivity, i.e. successive accumulation of migratory natural gases of different genesis with prevalence of gas phase and isotopic indicators of more gas-saturated parental source, epigenetic and syngenetic to sediments. It was found that maximum values of average gas saturation with CH4, ΣС2–С5, He and H2 in LSZ are typical for bottom sediments of the flanks of troughs, CO and CO2 – for the arch parts of uplifts. In sediments of monoclinal folds (structural terraces), minimal values of average gas saturation are observed, with the exception of the South Anyui Fault Zone. In general, gas saturation of LSZ sediments is determined by the complex impact of geological factors, with the major ones being: gas content of rock complexes and gas saturation of underlying sediments, fault and fold tectonics, a high degree of tectono-magmatic and seismic activity, a geostructural position, coal content, oil and gas content, as well as the depth of occurrence, organic saturation and material composition of OM in bottom sediments. The influence of the latter predetermined the formation and distribution of five geochemical fields of CH4, three of CO, ΣС2–С5, He and one of CO2, and one of H2 in LSZ.

Assessment of the Effect of Vehicular Emission on Air Quality in Uyo

The presence of vehicular traffic in urban city centers due to urban expansion occasioned by rapid population growth has been of immense concern for many years, as emissions from vehicle exhausts pose a major threat to both public health and environmental quality. This trend is expected to continue as ownership of vehicles keeps increasings. In this study, attempts are made to measure the concentration of traffic related emissions, with a view to assess the intricate relationships between vehicular emissions, their effect on surrounding air quality, and their impact on public health by extension, in Uyo metropolis, using USEPA air quality index. Six sampling locations were selected for this analysis. In selecting the study locations, special preference was given to accessibility, availability of open space free from shed, meteorological consideration of upward and downward directions, and areas with minimal local influence from vehicular movement. Also, consideration was given to the sensitivity and stability of the equipment, as well as its capability to reproduce results. The concentrations of the priority pollutants (i.e., CO, H2S, SO2 and O) were measured with highly sensitive digital portable meters (Crowcon Gasman Monitors) in each of the selected locations, at peak traffic periods, and compared with standard air quality ratings. The results of the study showed that locations IRJ, IPJ and NRJ recorded relatively the highest measured concentrations of the pollutants (CO, H2S and SO2) respectively, while IPJ, NRJ and IRJ recorded the lowest measured concentrations of same pollutants respectively. Continuous accumulation of these toxic gases in the air poses greater threat or may add to an already existing health burden of the residents of those locations. Therefore, further and thorough investigation is highly recommended to study the health impact of these contaminants in the residents.

Intra‐Craton Faults Characteristics, Development and Its Hydrocarbon Accumulation Significance in Mesozoic Strata at Southwestern Ordos Basin, China

ABSTRACTThe Ordos Basin is among China's largest petroliferous basins, with its southwestern part being a key exploration area. Prior studies indicated that the basin's internal structure was relatively simple, featuring minor developmental faults and primarily stratigraphic–lithologic reservoirs. However, recent research has identified numerous strike‐slip faults in the basin, and their relationship to oil and gas accumulations remains unclear. This study, using integrated interpretations of field outcrops, imaging logging and 3D seismic reflection data, clarifies the characteristics, morphology and formation mechanisms of multi‐period faults in the southwestern Ordos basin. Additionally, the study investigates the relationship between these faults and oil and gas accumulations. Results show that Mesozoic fractures in the southwestern basin are primarily NE‐ and NW‐trending. Seismic profiles reveal that these faults exhibit complex geometries, including upright structures in the Middle to Upper Triassic and floral structures in the Cretaceous. Coherence slices show that Lower Jurassic faults have linear structures NE‐ and NW‐trending, while Cretaceous faults exhibit parallel linear structures ENE‐trending. The study of fault displacement and morphology suggests two evolutionary patterns for Mesozoic faults in the basin: layered development and basement‐activated faulting. The widespread ENE‐ and NW‐trending faults represent a specific mode of tectonic stress transfer in stable cratonic areas with minimal basement fault influence. Conversely, some ENE‐trending faults are significantly influenced by basement activation during various geological periods, penetrating deeply into strata and exhibiting distinct segmentation on a planar scale. This differential fault development results in an uneven distribution of Jurassic oil and gas reservoirs. Significant accumulations of Jurassic oil and gas are found in the ENE‐trending tension–torsional strike‐slip sections, whereas many NW‐trending faults may negatively impact oil and gas reservoirs. This study elucidates the characteristics of Mesozoic faults in the southwestern Ordos Basin, offering valuable guidance for oil and gas exploration and development in the region.

Unlocking the potential of Cupriavidus necator H16 as a platform for bioproducts production from carbon dioxide.

The rapid global increase in fossil fuel and energy consumption has resulted in the accumulation of greenhouse gases, especially carbon dioxide (CO2), thus contributing to climate change. Therefore, transforming CO2 into valuable products could yield beneficial outcomes. In this review, the capabilities of Cupriavidus necator H16, a light-independent chemoautotrophic bacterium, as a host platform for the transformation of CO2 into diverse products are explored. We begin by examining the progress in synthetic biology toolkits, gas fermentation technologies, and engineering approaches, considering the chemoautotrophic metabolic traits of C. necator to enhance the capacity of the strain for CO2 fixation. Additionally, recent research focused on the metabolic engineering of C. necator H16 for the conversion of CO2 into biodegradable plastics, biofuels, bioactive compounds, and single-cell proteins was reviewed. Finally, we address the limitations affecting the advancement and utilization of C. necator H16 strain, such as inefficiencies and the range of product types, and offer several recommendations for enhancement. This review acts as a resource for the development of C. necator H16 cell factories and the industrial manufacture of products derived from CO2.

Non-Pillar Coal Mining by Driving Roadway During Mining Period in High-Gas Top-Coal-Caving Working Face

To solve the problem of the inability to achieve Y-shaped ventilation in the boundary coal mining of high-gas mines and the problem of gas accumulation in the upper corner of a fully mechanized mining face, non-pillar coal mining technology is proposed by a driving roadway during the mining period. A high-gas working face requires Y-shaped ventilation to achieve upper corner gas control, but Y-shaped ventilation conditions are not available at the boundary coal body. In order to handle this challenge, studies have suggested non-pillar coal mining technology, which involves excavating roadways while mining in order to achieve non-pillar coal extraction and use recoverable wide coal pillars. During the simultaneous excavation of a working face and roadway, studies analyzed the distribution characteristics of the complicated stress environment. Following an evaluation of the impact of coal pillar width on the quality of an excavation roadway, this study’s development is in terms of an effective technique for retaining coal pillars as established. During the mining period of a working face, in the goaf of the working face, the research analyzed the distribution properties of the gas flow field, and findings from the study indicate that the width of the recovered coal pillar influences the distribution of gas. Finally, the width of the coal pillar was comprehensively determined, forming non-pillar coal mining technology by a driving roadway during the mining period. The on-site practice has shown that using a wide coal pillar with a width of 70 m to protect the roadway significantly reduces the deformation of the surrounding rock in the mining roadway, the gas concentration at the return airway is lower than the safety production standard, and by decreasing the mining succession time by 15 months, studies achieved improving the working face’s coal extraction rate by 12.6%.

Analysis of Hydrocarbon Enrichment in Tight Sandstone Reservoirs in the Eastern Baiyun Depression

Based on the special geological background of the east and north slopes of the Baiyun Depression, the development conditions of Paleogene structure–lithology traps, the development conditions of high-quality reservoirs and the difficulty in characterizing the distribution characteristics are studied in this paper. It is concluded that the eastern Baiyun is located on the Baiyun–Liwan continental–oceanic large-scale intershell separation system, with a complex tectonic background and a tectono-sedimentary pattern of “fault and uplift interlocking and uplift and depression interphase”. The palaeo source sink system of the low bulge in the east of Yundong is restored, the favorable position of reservoir collective development and the favorable characteristics of reservoir–cap assemblage are clarified, and the paleo-geomorphology and sedimentary filling evolution law are clarified. Guided by the drive of oil and gas accumulation, three types of large and medium-sized structure–stratigraphic traps have been implemented in the eastern Baiyun system, including the convex inclined end, the restricted fault gully and the magmatic floor intrusion, and the corresponding oil and gas accumulation models have been perfected. By studying the structure, source and sink system and trap characterization of the eastern Baiyun basin, the development conditions and exploration direction of the large and medium-sized Palaeogene traps are systematically summarized.

Impact of Gas Accumulation on the Stability of Parallel Upward Ventilation in High-Temperature Sloped Shafts of Deep Wells

To explore the causes and influencing factors of wind flow oscillations in high-temperature inclined aisles of deep wells under parallel upward ventilation, this study conducts a comprehensive investigation using theoretical analysis and numerical simulations. Based on the kinetic analysis of gas flow, a discriminant formula for wind flow reversal in the side branch is derived. Further analysis identifies initial wind speed and branch length as key factors influencing the reversal. Both gas pressure and thermal pressure contribute to wind flow reversal in the side branch, and the opposing directions of these pressures cause high-temperature gas to periodically flow between the two branches, resulting in wind flow oscillations. A higher initial wind speed can effectively reduce the oscillation amplitude due to increased initial kinetic energy and a larger pressure difference, but it does not extend the oscillation duration. Increasing the branch length can suppress wind flow oscillations by increasing airflow frictional resistance and damping.

Gas charging and accumulation in deep coal measures of Daning-Jixian Block, Ordos Basin: insights from fluid inclusions and basin modeling

Gas charging and accumulation in deep coal measures of Daning-Jixian Block, Ordos Basin: insights from fluid inclusions and basin modeling

ASSESSMENT OF THE PROBABILITY OF OCCURRENCE OF EMERGENCY SITUATIONS DURING OPERATION OF THE PYROLYSIS PLANT

The article discusses the issues of reliability and safety of operation of a pyrolysis plant for the disposal of used tires, which, in the context of an increasing volume of waste and the need for their effective disposal, is an urgent topic. The problem statement is related to the identification of factors affecting the reliability of the installation and the development of methods to prevent emergencies.The purpose of the study is to analyz the reliability of the pyrolysis plant and develop recommendations for its improvement. To achieve this goal, the causes and probabilities of failures of system elements are investigated, an analysis using the failure tree method is carried out. This method made it possible to identify the weaknesses of the system and assess the probability of their failures, which is critical to prevent emergencies.An assessment of the reliability of the installation showed that the greatest contribution to the probability of accidents is made by a malfunction of the gas separation system. This element is the most vulnerable due to its complexity and importance in the pyrolysis process, as it is responsible for the safe and effective separation of pyrolysis products. Any malfunction of the gas separation system can lead to the accumulation of dangerous gases, increasing the risk of explosions and fires. The identified emergencies require special attention to the development of effective measures to minimize them.The article proposes methods to improve the reliability of the system, the main of which is the redundancy of the most vulnerable elements. This will significantly reduce the probability of failures and increase the overall reliability of the installation. In addition, it is recommended to carry out regular inspections and maintenance of all elements of the system. These measures will help to identify and eliminate potential malfunctions in a timely manner, which will significantly reduce the likelihood of failures that can lead to emergencies.Thus, ensuring the reliability and safety of a pyrolysis plant for the disposal of used tires requires an integrated approach. Enabling redundancy of vulnerable elements and regular maintenance will minimize the likelihood of failures that can lead to emergencies and guarantee stable and safe operation of the system. These measures will not only increase the efficiency of disposal, but also ensure reliable and long-term operation of the installation.This article focuses on the importance of identifying vulnerable elements of the system and conducting regular maintenance to improve the reliability and safety of operation of the pyrolysis plant.

Numerical Simulation of the Coal Measure Gas Accumulation Process in Well Z-7 in Qinshui Basin

The process of coal measure gas accumulation is relatively complex, involving multiple physicochemical processes such as migration, adsorption, desorption, and seepage of multiphase fluids (e.g., methane and water) in coal measure strata. This process is constrained by multiple factors, including geological structure, reservoir physical properties, fluid pressure, and temperature. This study used Well Z-7 in the Qinshui Basin as the research object as well as numerical simulations to reveal the processes of methane generation, migration, accumulation, and dissipation in the geological history. The results indicate that the gas content of the reservoir was basically zero in the early stage (before 25 Ma), and the gas content peaks all appeared after the peak of hydrocarbon generation (after 208 Ma). During the peak gas generation stage, the gas content increased sharply in the early stages. In the later stage, because of the pressurization of the hydrocarbon generation, the caprock broke through and was lost, and the gas content decreased in a zigzag manner. The reservoirs in the middle and upper parts of the coal measure were easily charged, which was consistent with the upward trend of diffusion and dissipation and had a certain relationship with the cumulative breakout and seepage dissipation. The gas contents of coal, shale, and tight sandstone reservoirs were positively correlated with the mature hydrocarbon generation of organic matter in coal seams, with the differences between different reservoirs gradually narrowing over time.

A Segmented Along the Channel Test Cell for Locally Resolved Analysis at High Current Densities in PEM Water Electrolysis

Abstract For the scale-up of proton exchange membrane (PEM) water electrolysis, understanding the cell behavior on industrial scale is a prerequisite. A proper distribution of current and temperature in the cell can improve performance and decrease overall degradation effects. Due to water consumption as well as the concomitant gas evolution and accumulation, gradients and inhomogeneities along the reaction coordinate are expected. These effects increase along the water supply channels of a flow field and are expected to lead to spatial gradients in cell performance and temperature. At high current densities (> 5 A∙cm-2) these effects are anticipated to be critical due to the high amount of gas produced and the increased degradation rate resulting from the high overpotentials. 
In this study we present a new test cell that is segmented along the flow field channels and is designed for the operation at high current densities of up to 10 A∙cm-2. With this approach it is possible to analyze performance gradients and the spatial distribution of loss processes under industry-relevant conditions by measuring the current density and temperature distribution and by performing locally resolved electrochemical impedance spectroscopy (EIS).

Numerical modeling and parameter optimization of the combustion chamber in a tower-type zinc refining furnace

With the implementation of “coal-to-gas” projects, the tower-type zinc refining furnace (TZRF) has encountered a mismatch between high-calorific value fuel and the primary combustion system. To address this issue, this study conducted a full-scale modeling of the combustion and heat transfer processes in the TZRF combustion chamber using computational fluid dynamics. An in-depth analysis and condition diagnosis of the TZRF were performed, elucidating the key causes of deteriorating furnace conditions, reduced efficiency, and decreased production capacity following fuel replacement. This study shows that the flow ratios of gas outlets are unevenly distributed, leading to poor mixing of natural gas and air, resulting in an uneven temperature field in the TZRF. A low-temperature zone is clearly observed below the second-layer burner, where significant accumulation of natural gas fails to combust completely. Although tilting the first-layer burner upward slightly enhances the overall heat transfer performance of the tray, it detrimentally affects the overall combustion of natural gas in the TZRF. The deployment of third-layer air outlets substantially eliminates low-temperature zones, expands the range of high-temperature zones, and significantly improves the furnace condition. The optimal flow ratio of the third-layer air outlets is 29.57 %.

Influence of Aspect Ratio of Migration Space on Gas Migration and Accumulation Mechanisms of Different Types of Gas Reservoirs

Influence of Aspect Ratio of Migration Space on Gas Migration and Accumulation Mechanisms of Different Types of Gas Reservoirs

The influence of pulsation ventilation on the removal and distribution of gas accumulation areas during gas leakage in industrial plants

A ventilation system with a constant velocity air supply might form airflow stagnant zones in industrial plants, making it challenging to dilute hazardous gas effectively. In this study, a novel ventilation mode called pulsating ventilation, which can potentially dilute the hazardous gas better, was applied in a ventilated room with nozzle air supply. Three different scenarios of gas accumulation were assumed, with the location of gas accumulation situated at the rear, near the floor, and in the corners of the room. Both the distribution of CO2 concentration and the efficiency of reducing the indoor CO2 concentration to the safety threshold were analyzed to evaluate the ventilation performance of pulsating ventilation. The results showed that pulsating ventilation outperformed constant velocity air supply in expeditiously eradicating gas accumulation areas for equivalent total air volumes. When the gas accumulation areas were located at the rear of the room, close to the floor, and in the corner of the room, pulsation ventilation reduced the time for the indoor CO2 concentration to drop to the safety threshold by 36.19%, 27.23%, and 36.25%, respectively. Holding the period constant, an increased amplitude correlated with a swifter decrease in peak pollutant concentration. Except for the case where the gas accumulation areas are close to the floor, when the amplitude is constant, the larger the period, the faster the peak concentration in the gas accumulation areas decreases.