Gas Volume Research Articles

Investigation of co-gasification characteristics of coal with wood biomass and rubber seals in a fixed bed gasifier

The thermochemical processing of waste in gasification to hydrogen-rich gas is considered to be a novel, promising technological option, complementing the currently employed hydrogen production methods and an effective and environment friendly way of waste utilization. The paper discusses the results of the experimental study on this novel technological option of co-gasification of coal with automotive rubber seals or wood chips in a fixed bed reactor with the application of oxygen and steam mixture as a gasification agent. The experiments were performed with the use of waste to coal blending ratio of 10:90, 15:85 and 20:80 (%w/w), and at the temperature range of 700–900 °C. The contents of carbon monoxide, carbon dioxide, hydrogen and methane in the gaseous product reported in the study were in the range of 35–36 %vol., 31–33 %vol., 29–31 %vol., and 0.10–0.16 %vol., respectively. The maximum values of the lower heating value and the total gas volume were reported for fuel blends of 10%w/w waste content at 900 °C. Hydrogen and carbon monoxide production increased with process temperature, and declined with waste fraction in a fuel blend. Gasification of fuel blends composed of coal and rubber resulted in higher hydrogen production than the gasification of coal-biomass fuel blends, which may be attributed principally to the higher fixed carbon content and higher alkali index of rubber when compared to the respective values of wood chips.

Technical and Environmental Assessment of the Consequences of Accidents on Offshore Gas Pipelines in the Baltic Sea

The failure of the Nord Stream pipelines in the Baltic Sea in September 2022 had significant technical and economic consequences not only for the European Union energy sector and the gas production and transmission industry of the Russian Federation, but also entailed a number of environmental consequences, the scale of which has yet to be explored. During the preliminary assessment of the consequences of the accident, the team of scientists from the Kant Baltic Federal University, the Atlantic branch of the VNIRO and the Shirshov Oceanology Institute of the Russian Academy of Sciences calculated the composition of the gas mixture emitted and assessed its volume, studied potential environmental damage to the biogeocenoses of the Western and Southern Baltic, calculated the impact of the gases emitted on global temperature. The studies were based on data obtained from open sources and allow us to give a preliminary assessment of the environmental impact of the accident. The combination of analytical, evaluation and research methods used is basically a classic approach to accounting for the volume of gas emissions and their subsequent impact. Leakage volume was calculated by first determining the volume of gas that entered the natural environment after impact (before the emergency valves were closed), and then determining the second volume of gas (until pressure stabilization in the cut-off pipe sections and in the environment). Based on the information on the biota in the water area and the nature of the gas movement, an estimated impact on biological organisms in the zone of the Bronholm depression was determined. Based on the models of the influence of methane emissions on climatic parameters, the preliminary consequences of the emission were established. The assessment of the environmental impact on the water area was conducted and the main directions of further research determined. The potential ways to minimize the environmental consequences of the accident in the short and long term have been considered.

Analysis of two-phase gas-liquid flow in an Electric Submersible Pump using A CFD approach

This study comprehensively analyzes a mixed-flow Electric Submersible Pump's (ESP) performance under challenging conditions of low flow rates and high gas fractions. The research leverages a computational model built on the Eulerian-Eulerian methodology, adeptly solving the 3D incompressible Navier-Stokes equations for each phase. To ensure an encompassing depiction of the flow dynamics within the ESP, the model considers critical parameters such as the bubble diameter and interphase forces, including drag, lift, and virtual mass force.Key findings reveal that the ESP's performance deteriorates markedly under the studied conditions. One of the primary influencers is the phenomenon of gas locking, where gas accumulation within the impeller hampers the consistent flow of liquid, thereby degrading the pump's efficiency. In addition, the model delineated the occurrence of the surging phenomenon across diverse gas volume fractions and rotational speeds, which further exacerbates the reduction in the ESP's performance. Intriguingly, the bubble diameter was identified as a decisive factor, especially at minuscule flow rates. Large bubble diameters instigate the formation of gas pockets on the suction side of the vane, culminating in a segregated flow pattern and further declining pump efficiency.On the other hand, the drag force is the primary interaction force between phases of gas-liquid flow. Other interfacial forces, such as lift and virtual mass force, change the pump's performance but do not affect the gas flow and distribution patterns for a one-stage configuration. Results show that the Schiller-Neuman drag coefficient offers a better fit than the Bozano-Dente coefficient.Conclusively, the study underscores the indispensable role of nuanced computational models in elucidating the intricate flow dynamics within ESPs, especially under conditions fraught with operational challenges. The insights gleaned enrich our understanding of ESP performance dynamics and provide a roadmap for designing more resilient and efficient pumping systems in the future.

Acquiring Hyperpolarized 129Xe Magnetic Resonance Images of Lung Ventilation.

Hyperpolarized 129Xe MRI comprises a unique array of structural and functional lung imaging techniques. Technique standardization across sites is increasingly important given the recent FDA approval of 129Xe as an MR contrast agent and as interest in 129Xe MRI increases among research and clinical institutions. Members of the 129Xe MRI Clinical Trials Consortium (Xe MRI CTC) have agreed upon best practices for each of the key aspects of the 129Xe MRI workflow, and these recommendations are summarized in a recent publication. This work provides practical information to develop an end-to-end workflow for collecting 129Xe MR images of lung ventilation according to the Xe MRI CTC recommendations. Preparation and administration of 129Xe for MR studies will be discussed and demonstrated, with specific topics including choice of appropriate gas volumes for entire studies and for individual MR scans, preparationand delivery of individual 129Xe doses, and best practices for monitoring subject safety and 129Xe tolerability during studies. Key MR technical considerations will also be covered, including pulse sequence types and optimized parameters, calibration of 129Xe flip angle and center frequency, and 129Xe MRI ventilation image analysis.

Influence of pressure disturbance wave on dynamic response characteristics of liquid film seal for multiphase pump

Slug flow or high GVF (Gas Volume Fraction) conditions can cause pressure disturbance waves and alternating loads at the boundary of mechanical seals for multiphase pumps, endangering the safety of multiphase pump units. The mechanical seal model is simplified by using periodic boundary conditions and numerical calculations are carried out based on the Zwart-Gerber-Belamri cavitation model. UDF (User Define Function) programs such as structural dynamics equations, alternating load equations, and pressure disturbance equations are embedded in numerical calculations, and the dynamic response characteristics of mechanical seal are studied using layered dynamic mesh technology. The results show that when the pressure disturbance occurs at the inlet, as the amplitude and period of the disturbance increase, the film thickness gradually decreases. And the fundamental reason for the hysteresis of the film thickness change is that the pressure in the high-pressure area cannot be restored in a timely manner. The maximum value of leakage and the minimum value of axial velocity are independent of the disturbance period and determined by the disturbance amplitude. The mutual interference between enhanced waves does not have a significant impact on the film thickness, while the front wave in the attenuated wave has a promoting effect on the subsequent film thickness changes, and the fluctuation of the liquid film cavitation rate and axial velocity under the attenuated wave condition deviates from the initial values. Compared with pressure disturbance conditions, alternating load conditions have a more significant impact on film thickness and leakage. During actual operation, it is necessary to avoid alternating load conditions in multiphase pump mechanical seals.

A network model for gas invasion into porous media filled with yield-stress fluid

This study investigates the gas invasion into a porous medium filled with a yield-stress fluid. A pore–throat network model is employed to represent the porous media, and a semi-analytical approach is used for simulating the gas propagation. The effect of throat radii, fluid yield stress and network size on the exit time and gas volume fraction retained inside the porous medium are explored. The stability of the network in response to inflow perturbations is also examined. The uniform network appears to be optimal from the perspective of preventing flow.

Processing plastic waste via pyrolysis-thermolysis into hydrogen and solid carbon additive to ethylene-vinyl acetate foam for cushioning applications

A strategy for enhancing value creation from pyrolysis gas and oil, derived from plastic waste, through the generation of two additional outputs of solid carbon and hydrogen was investigated. Three types of hard-to-recycle plastic waste (marine plastic litter, household mixed plastics and cosmetic products packaging) were thermally treated in two stages: (i) decomposition of feedstock into gas and oil via pyrolysis at 600 °C; and (ii) thermolytic conversion of the pyrolysis gas and a fraction of oil into hydrogen and solid carbon at 1300 °C separately. The thermolysis of both pyrolysis gas and oil fractions predominantly resulted in the production of solid carbon (39–70 wt% per plastic feedstock and carbon content of 91.3–98.6 wt%) and H2-rich gas (H2 yield of 5.9–10.8 wt% per plastic waste feedstock and H2 content of 71.4–97.2 vol% per gas volume). The incorporation of pyrolysis oil into the thermolysis process could enhance the outputs of solid carbon and hydrogen. Characterizations of solid carbon and hydrogen obtained from pyrolysis gas and oil fractions were further conducted. The observed similar properties of H2 and solid carbon from pyrolysis gas and oil supported the feasibility of introducing all the pyrolytic products together into the thermolysis process without condensation of oil. To enhance the value of these solid carbon derived from plastics for practical usage, we utilized the obtained solid carbon as a reinforcing agent for polymer composite foam development. The solid carbon reinforced composite foam displayed great abrasion resistance (wear loss: 240 mg), compression strength (0.347 MPa), and dynamic impact properties (energy returned: 124 J/m and energy absorbed: 57.3 J/m), emphasizing the viability of solid carbon as a nucleating agent and reinforcing filler in polymer foam for cushioning applications. Overall, the strategy of pyrolysis-thermolysis, which harnesses both pyrolysis gas and oil, unlocks additional value creation by producing two new outputs from plastic waste. Depending on the market prices for solid carbon and hydrogen, this can substantially change the economics of plastic waste management and create new revenue streams, incentivizing plastic waste collection and processing.

Combined Spectroscopy System Utilizing Gas Electron Multiplier and Timepix3 Technology for Laser Plasma Experiments

We present an innovative X-ray spectroscopy system to address the complex study of the X-ray emissions arising from laser–target interactions, where the emissions occur within extremely brief intervals from femtoseconds to nanoseconds. Our system combines a Gas Electron Multiplier (GEM) detector with a silicon-based Timepix3 (TPX3) detector. These detectors work in tandem, allowing for a spectroscopic radiation analysis along the same line of sight. With an active area of 10 × 10 cm2, the GEM detector allows for 1D measurements for X-ray energies (2–50 keV) by utilizing the full 10 cm gas depth. The high-energy part of the radiation beam exits through a downstream side window of the GEM without being absorbed in the gas volume. Positioned side-on at the GEM detector’s exit, the TPX3 detector, equipped with a pixelated sensor (55 µm × 55 µm; active area 14 mm × 14 mm), uses its full 14 mm silicon sensor to detect hard X-rays (50–500 keV) and gamma rays (0.5–10 MeV). We demonstrate the correct operation of the entire detection system and provide a detailed description of the Timepix3 detector’s calibration procedure, highlighting the suitability of the combined system to work in laser plasma facilities.

Gas and energy security in Germany and central and Eastern Europe

Russia's weaponization of gas supplies caused a shock to the energy security of Central and Eastern Europe in 2022. Countries responded by increasing alternative energy supplies and developing new natural gas supply routes, namely through increased LNG import capacity and new interconnectors. At the same time, market forces in the form of higher prices largely ensured an efficient allocation of scarce gas across the region and encouraged the necessary savings. We examine how gas flows to and within the region have been changing in the short- and medium-term and explore the role of renewable and nuclear energy as well as hydrogen in the long-term. We conclude that mitigating the effects of this shock requires the EU to prioritize policies that foster the integrity of its energy market. Government policies and higher fossil fuel prices will encourage the build-up of renewables, increasing energy security medium term. Only in combination with consistently high energy savings and the procurement and distribution of sufficient gas volumes from the global LNG market can Russian supplies be replaced. It is thus the interplay of supply and demand measures that allowed Central and Eastern Europe to withstand the extraordinary shock of 2022.

Rancang Bangun Sistem Monitoring Kebocoran Gas, Suhu, dan Kelembapan pada Dapur Berbasis Internet of Things Menggunakan Mikrokontroler Wemos D1 Mini

This research is about the design of a gas leak monitoring system, temperature, and humidity in an Internet of Things (IoT) based kitchen using a Wemos D1 Mini microcontroller. The system aims to overcome the problem of uncontrolled temperature and humidity that affect the quality of food, as well as the high risk of LPG gas explosion due to leakage. A gas leak monitoring system using MQ2 sensor, monitoring temperature and humidity values using DHT 11 sensor and microcontroller using Wemos D1 Mini. The MQ2 sensor will detect a gas leak from the volume of gas in the room. If the gas value in the room is 300 ppm, the buzzer will sound. The DHT 11 sensor will monitor the temperature and humidity percentage. Then the Wemos d1 mini will send the value to the BLYNK database and will be displayed in the application using Kodular. This research is expected to contribute to the field of IoT-based monitoring systems, improving the safety and comfort of the kitchen environment.

A Dual Mode Ultrasonic Method for Measuring Gas Volume Fraction in Two-Phase Slug Flows

A Dual Mode Ultrasonic Method for Measuring Gas Volume Fraction in Two-Phase Slug Flows

Why we should care about gas pockets in online adaptive MRgRT: a dosimetric evaluation.

Contouring of gas pockets is a time consuming step in the workflow of adaptive radiotherapy. We would like to better understand which gas pockets electronic densitiy should be used and the dosimetric impact on adaptive MRgRT treatment. 21 CT scans of patients undergoing SBRT were retrospectively evaluated. Anatomical structures were contoured: Gross Tumour Volume (GTV), stomach (ST), small bowel (SB), large bowel (LB), gas pockets (GAS) and gas in each organ respectively STG, SBG, LBG. Average HU in GAS was converted in RED, the obtained value has been named as Gastrointestinal Gas RED (GIGED). Differences of average HU in GAS, STG, SBG and LBG were computed. Three treatment plans were calculated editing the GAS volume RED that was overwritten with: air RED (0.0012), water RED (1.000), GIGED, generating respectively APLAN, WPLAN and the GPLAN. 2-D dose distributions were analyzed by gamma analysis. Parameter called active gas volume (AGV) was calculated as the intersection of GAS with the isodose of 5% of prescription dose. Average HU value contained in GAS results to be equal to -620. No significative difference was noted between the average HU of gas in different organ at risk. Value of Gamma Passing Rate (GPR) anticorrelates with the AGV for each plan comparison and the threshold value for GPR to fall below 90% is 41, 60 and 139 cc for WPLANvsAPLAN, GPLANvsAPLAN and WPLANvsGPLAN respectively. GIGED is the right RED for Gastrointestinal Gas. Novel AGV is a useful parameter to evaluate the effect of gas pocket on dose distribution.

Partial Differentiation and the Coefficient of Thermal Expansion: A Multivariable Calculus Activity Connecting with Chemistry

We describe the components and implementation of an activity for multivariable calculus featuring applications to the field of chemistry. This activity focuses on the isobaric thermal expansion coefficient found using partial differentiation of the volume of an ideal gas with respect to temperature as pressure is held constant. Broader goals of this activity include enhancing calculus conceptual understanding, encouraging further interdisciplinary study and exploration, and cultivating mathematicians and scientists with broader and deeper backgrounds.

Direct numerical simulation of bubble collision, bounce and coalescence in bubble-induced turbulence

A direct numerical simulation study has been carried out to better understand the dynamics of deformable bubbles in bubble-induced turbulence. A mathematical model for bubble collision, bounce and coalescence is developed based on the Volume-of-Fluid (VoF) method. A surface-tension-holding film thickness δc is introduced to determine whether the bubbles will coalesce or bounce after collision. Bubbly flows with the gas volume fractions αg=5.6% (low), 11.2% (medium) and 22.1% (high) are considered in the study. The DNS results show that the dissipation of turbulent kinetic energy in the cases under consideration takes place when the wavenumber κ is smaller than twice the wavenumber for the bubble diameter 2κd. The bubble-induced turbulence is anisotropic at the length scales close to the bubble diameter due to the elongated turbulent structures in the bubble-rising direction. The bubbles collide intensively with each other when they are in a cluster surrounded by the liquid with low pressure. Parallel clustering of bubbles is found when the gas volume fraction has a low or medium value. Three-dimensional clustering is found when the bubbles are densely populated. Two different mechanisms of bubble collision have been identified from the DNS results, termed parallel collision and vertical collision. Parallel collision is often observed when bubbles are sparsely populated. In a parallel collision, the relative velocity of the bubbles slows down as two bubbles approach each other due to the jet flow between them, while the relative velocity increases sharply after the bounce. In a vertical collision, by contrast, the relative velocity of bubbles accelerates as two bubbles approach each other, while it slows down during the collision. Vertical collisions occur when the bubbles are more densely populated. The numerical results also show the significant effects of δc on bubble coalescence.

Analysis of different Explosive substance

Explosive wing: An explosion is a chemical reaction which is basically exothermic in nature, the products get heated up to extremely high temperature and exert high pressure that shatters the confining walls. The explosion reactions are rapid, and are associated with oxidation reaction. Releasing heat, light and large volume of gas. Explosive material: Consists of chemical compounds or their mixture which when subjected to sudden shock (mechanical or thermal) get oxidised, Releases huge amount of energy in a extremely short period of time (which can be observed in the form of explosion)

Effect of Postoperative Trendelenburg Positioning in Reducing Shoulder Pain after Laparoscopic Cholecystectomy

Background and Objective: Shoulder pain is one of the most common complaints of patients after laparoscopic cholecystectomy, which seems to be closely related to the residual volume of carbon dioxide gas used during surgery. Therefore, this study was conducted with the aim of investigating the effect of Trendelenburg positioning after surgery in reducing shoulder pain in patients. Materials and Methods: This study was conducted as a randomized clinical trial in 58 patients who were eligible for laparoscopic cholecystectomy. Patients were enrolled in the study by simple random sampling and randomly assigned to supine (control) and Trendelenburg (intervention) positions. After complete awakening in the recovery room, the patients in the intervention group were placed in the Trendelenburg position (30 degrees), while the patients in the control group were placed in the supine position for 30 minutes. The level of pain was measured 6, 12, 24and 48 hours after completion of the procedure using the NRS scale. Data analysis was performed using SPSS version 24 software. Results: The results of this study show that there is a significant difference between the pain intensity 6, 12, 24and 48 hours after the end of the intervention between the two intervention and control groups (P >0.05). The pain in the intervention group is therefore lower than in the control group. Conclusion: As a simpleeffective, and inexpensive technique, the Trendelenburg position can reduce shoulder pain in patients undergoing laparoscopic cholecystectomy

Multi-criteria site selection workflow for geological storage of hydrogen in depleted gas fields: A case for the UK

Underground hydrogen storage (UHS) plays a critical role in ensuring the stability and security of the future clean energy supply. However, the efficiency and reliability of UHS technology depend heavily on the careful and criteria-driven selection of suitable storage sites. This study presents a hybrid multi-criteria decision-making framework integrating the Analytical Hierarchy Process (AHP) and Preference Ranking Organisation Method for Enrichment of Evaluations (PROMETHEE) to identify and select the best hydrogen storage sites among depleted gas reservoirs in the UK. To achieve this, a new set of site selection criteria is proposed in light of the technical and economic aspects of UHS, including location, reservoir rock quality and tectonic characteristics, maximum achievable hydrogen well deliverability rate, working gas capacity, cushion gas volume requirement, distance to future potential hydrogen clusters, and access to intermittent renewable energy sources (RESs). The framework is implemented to rank 71 reservoirs based on their potential and suitability for UHS. Firstly, the reservoirs are thoroughly evaluated for each proposed criterion and then the AHP-PROMETHEE technique is employed to prioritise the criteria and rank the storage sites. The study reveals that the total calculated working gas capacity based on single-well plateau withdrawal rates is around 881 TWh across all evaluated reservoirs. The maximum well deliverability rates for hydrogen withdrawal are found to vary considerably among the sites; however, 22 % are estimated to have deliverability rates exceeding 100 sm3/d, and 63 % are located within a distance of 100 km from a major hydrogen cluster. Moreover, 70 % have access to nearby RESs developments, with an estimated cumulative RESs capacity of approximately 181 GW. The results highlight the efficacy of the proposed multi-criteria site selection framework. The top five highest-ranked sites for UHS based on the evaluated criteria are the Cygnus, Hamilton, Saltfleetby, Corvette, and Hatfield Moors gas fields. The insights provided by this study can contribute to informed decision-making, sustainable development, and the overall progress of future UHS projects within the UK and globally.

A Pragmatic Approach to the Economic Assessment of Green Synthetic Methane Power in the Baltics

The synthesis of methane from hydrogen and carbon dioxide creates an energy resource that is suitable for long-term storage. Once this process is powered by renewable electricity, it produces a clean fuel for producing electricity and heat and supports large-scale renewable energy deployment, energy transition and climate change mitigation. This paper proposes a pragmatic approach to assessing the economic potential of synthetic methane-based power. Today, natural gas plays an important role in the Baltic region due to the existing infrastructure, which includes a transmission and distribution pipeline network, gas power plants and a large underground storage reservoir. Replacing natural gas with synthetic methane would fulfil carbon emission reduction ambitions. In this paper, we simulate electricity producers’ actions at market conditions and consider the generation portfolio in the Baltics and the interconnections with Scandinavia and Poland operating in the NORDPOOL electricity market. As a result of these calculations, we obtain the volume of the synthetic gas, the production costs, the volume of gas storage, the installed capacity of the gas power plant, and the investments required to ensure energy transition and system adequacy. These results are essential for the informed decisions made by policymakers, investors and system operators.

Harvesting of Dunaliella salina using electrocoagulation with helix electrode and producing HHO gas as promising Hydrogen fuel

<p>Biofuels obtained from renewable sources are the only alternative in the global economy from a sustainable point of view. Microalgae have shown tremendous potential as a major source of biomass production that can be used as biofuels. At the same time, gas hydrogen is a non-polluting energy source because it is produced from renewable sources. This study aims to analyze the harvesting efficiency of Dunaliella salina using electrocoagulation with a helix electrode and having HHO gas as hydrogen fuel. D salina harvesting using an EC reactor made of acrylic is done on a batch scale. Helix-shaped type 304 stainless steel is the cathode, and solid cylindrically-shaped Fe is the anode. The voltage set is 20 Volts, while the electrolysis time is varied between 1. 5. 10. 15. 20. 25 and 30 minutes. The harvesting efficiency of D salina using electrocoagulation with a helix electrode was the highest at 84.74%. The highest concentration of dissolved hydrogen gas was 1.753 ppm. The highest volume of HHO gas was 1978 mL resulting from a 30-minute electrocoagulation with a helix electrode, 20-volt voltage. Nanoscale glovaries are formed on the electrode through heterogeneous nucleation at the solid-liquid interface. After nucleation, the nanobubbles grow, and the buoyancy forces of the growing bubbles cause gas release from the cathode surface. This process continues until it causes many bubbles to produce 1978 mL HHO gas for 30 minutes. During the study, the convex HHO gas formed helped remove coagulated D salina floc through electro-flotation. When the time of D salina harvesting using electrocoagulation with a helix electrode significantly affects D salina harvesting efficiency, gas HHO volume, pH, and temperature, harvesting time has no significant effect on dissolved hydrogen gas concentration and ORP.</p>

A study for hydrogen evolution on Pt–MnCu electrocatalyst

Electrocatalysts to be used in electrolysis, which is one of the hydrogen production methods, are very important. The development of electrocatalysts is related to the internal structure of combinated more than one metal. In the present work, the graphite substrate is coated with manganez (C/Mn), manganez-copper (C/MnCu) and this surface is modified with platinum nanoparticles (C/MnCu–Pt) using the electrodeposition method. Prepared electrocatalysts are used for characterization, hydrogen evolution reaction (HER) and stability using cyclic voltammetry (CV), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), X-ray diffraction (XRD), cathodic current-potential curves, electrochemical impedance spectroscopy (EIS) and chronoamperometry (CA). Hydrogen gas is measured in a basic environment by establishing an experimental electrolysis setup on these electrocatalysts. Results showed that binary MnCu enhances the characteristic current density of Tafel curves, reduces the polarization resistance and enhances the hydrogen gas volume compared to graphite substrate and single Mn coating. Apart from that, much more effective results are obtained on the C/MnCu–Pt electrocatalyst. Namely, a very high exchange current density (io = 5.50 mA cm−2), a very low polarization resistance (3.2 Ω cm2) and a very low overpotential (50 mV) at 10 mA cm−2 are obtained on the C/MnCu–Pt electrocatalyst. In addition to high performance, C/MnCu–Pt electrocatalyst exhibits good stability in alkaline medium.