198 Results Found

The nonideal behavior of polymeric membranes during separation of gas mixtures can be quantified via the solution-diffusion theory from experimental mixed-gas solubility and permeability coefficients. In this study, CO2-CH4 mixtures were sorbed at 35...

This paper presents a novel method for transient and steady state mixed gas permeation measurements, using a quadrupole residual gas analyser for the on-line determination of the permeate composition. The on-line analysis provides sufficiently quick...

The most widely used method to measure the transport properties of dense polymeric membranes is the time lag method in a constant volume/pressure increase instrument. Although simple and quick, this method provides only relatively superficial, averag...

The exchange of CH4 by CO2 in gas hydrates is of interest for the production of natural gas from methane hydrate with net zero climate gas balance, and for managing risks that are related to sediment destabilization and mobilization after gas-hydrate...

The effect on the gas transport properties of Matrimid®5218 of blending with the polymer of intrinsic microporosity PIM-EA(H2)-TB was studied by pure and mixed gas permeation measurements. Membranes of the two neat polymers and their 50/50 wt % blend...

This study presents the development of a robust numerical model for simulating underground hydrogen storage (UHS) in salt caverns, with a particular focus on the interactions between original gas-methane (CH4) and injected gas represented by hydrogen...

Membrane-based processes are taking a more and more prominent position in the search for sustainable and energy-efficient gas separation applications. It is known that the separation performance of pure polymers may significantly be improved by the d...

Despite the outstanding chemical, thermal and transport properties of amorphous and glassy perfluorinated polymers, only few works exist on the preparation and transport properties of perfluoropolymer/molecular sieves mixed-matrix membranes (MMMs), p...

A triptycene-based diamine, 1,3,6,8-tetramethyl-2,7-diamino-triptycene (TMDAT), was used for the synthesis of a novel solution-processable polyamide obtained via polycondensation reaction with 4,4′-(hexafluoroisopropylidene)bis(benzoic acid) (6...

For industrial CO2 utilization, the supply of concentrated CO2 within a continuous, high-volume stream at high temperatures remains a substantial requirement. Membrane processes offer a simple and efficient method to provide CO2 in this form. While s...

Fluorinated polyimides incorporated with triptycene units have gained growing attention over the last decade since they present potentially interesting selectivities and a higher free volume with respect to their triptycene-free counterparts. This wo...

Reinforced thermoplastic composite pipes (RTPs) have been widely used for oil and gas gathering and transportation. Polyvinylidene fluoride (PVDF) has the greatest potential as a thermoplastic liner of RTPs due to its excellent thermal and mechanical...

Regarding the use of SF6 in medium voltage switchgear (MVS), a review of alternatives was encouraged by the European Parliament in Regulation No 517/2014. This is aimed at a new regulatory change, that is expected soon, which will include its prohibi...

Carbon dioxide (CO2)-enhanced coalbed methane recovery involves a complex process of mixed-gas adsorption, desorption, and diffusion–transport. The literature suggests that an appropriate range of CO2 injection pressure and an optimal injection...

This work illustrates the potential of using atomistic molecular dynamics (MD) and grand-canonical Monte Carlo (GCMC) simulations prior to experiments in order to pre-screen candidate membrane structures for gas separation, under harsh conditions of...

As kerogen is the main organic component in shale, the adsorption capacity, diffusion and permeability of the gas in kerogen plays an important role in shale gas production. Based on the molecular model of type II kerogen, an organic nanoporous struc...

In this paper, using the numerical simulation analysis software MATLAB and Fire Dynamics Simulation (FDS), the corresponding gas leakage diffusion model and turbulence leakage diffusion module were used to study the diffusion law and fire hazard of v...

Mixing of carbon dioxide dissolved in a multicomponent gas mixture at different pressures was researched. It was found that the mechanical equilibrium of the ternary gas mixture 0.4163H2 (1) + 0.5837CO2 (2) − N2 (3) is violated at a pressure of p = 0...

With the breakthrough in mixing hydrogen into natural gas pipelines for urban use, the widespread application of hydrogen-blended natural gas (HBNG) in energy delivery is imminent. However, this development also introduces significant safety concerns...

The grain boundary diffusion process employing a mixed diffusion source, comprising heavy rare-earth elements and low-melting metals, significantly enhances the coercivity (Hcj) of sintered Nd-Fe-B magnets. In the present study, Tb and Ga were deposi...

This paper establishes a mathematic model of a CO2 two-phase ejector to investigate flow distribution in the components of a mixing chamber and diffuser. The suction chamber was modeled using the characteristic line method to describe the development...

Gas transport parameters such as gas diffusivity (Dp/D0), air permeability (ka), and their dependency on void space (air-filled porosity, ε) in a waste body govern convective air and gas diffusion at solid waste dumpsites and surface emission of vari...

Even bubble column reactors (BCR) and airlift reactors (ALR) have been developed in terms of various related aspects towards mass transfer enhancement, the effective analysis of gas diffuser types on mass transfer and gas–liquid hydrodynamic characte...

A cushion gas is an indispensable and the most expensive part of underground natural gas storage. Using CO2 injection to provide a cushion gas, not only can the investment in natural gas storage construction be reduced but the greenhouse effect can a...

The gas desorption behavior of coal is a key basis for guiding gas parameter determination, optimizing gas extraction, and preventing gas-related disasters. Coal in mine working faces typically exhibits a mixed particle size distribution. However, re...

Polysulfone-based mixed matrix membranes (MMMs) incorporated with silica nanoparticles are a new generation material under ongoing research and development for gas separation. However, the attributes of a better-performing MMM cannot be precisely stu...

The existence of various native or nonnative species/fluids, along with having more than one phase in the subsurface and within the integrated production and injection systems, generates unique challenges as the pressure, temperature, composition and...

The objective of this study was to optimize the design of the injection nozzle hole of the fuel injector of a model MGT engine. To achieve a higher combustion efficiency of the mixed gas in the combustion chamber, first, well-mixed homogeneous gas sh...

Thermal barrier coatings serve as thermal insulation and antioxidants on the surfaces of hot components. Different from the frequent thermal cycles of aero-engines, a heavy-duty gas turbine experiences few thermal cycles and continuously operates wit...

The uniformity of secondary air (SA) in large-scale CFB boilers has an important influence on gas-solid flow and combustion, but was seldom considered in previous studies. Numerical simulation based on the Eulerian–Eulerian and RNG k-ε turbulence mod...

Conical diffusers are widely used in technical devices (gasifiers, turbines, combustion chambers) and technological processes (ejectors, mixers, renewable energy). The perfection of flow gas dynamics in a conical diffuser affects the intensity of hea...

CO2-enhanced tight oil production can increase crude oil recovery while part of the injected CO2 is geologically sequestered. This process is influenced by factors such as gas injection rate, oil/gas viscosity ratio, and contact angle. Understanding...

Volatile organic compounds (VOCs) are important sources of atmospheric pollutants on account of their high recycling value. The membrane of dense silicone rubber polydimethylsiloxane (PDMS) has wide-ranging prospects for the separation and recovery o...

The length and pattern of air–fuel mixing plays a significant role in the uniformity, flame temperature, and emission characteristics, which can lead to a superior product quality in a non-oxidizing direct fired burner for a cold-rolled steel plate f...

In this paper, the Weather Research and Forecasting (WRF) model is coupled with the computational fluid dynamics (CFD) model to study the diffusion model of the accidental leakage of hazardous gas under different atmospheric stability conditions. Fir...

This study discusses the influence of the composition of a ternary gas mixture on the possibility of occurrence of convective instability under isothermal conditions due to the difference in the diffusion abilities of the components. A numerical stud...

Direct-methanol fuel cell (DMFC) systems are comparatively simple, sometimes just requiring a fuel cartridge and a fuel cell stack with appropriate control devices. The key challenge in these systems is the accurate determination and control of the f...

Gas fuel direct injection (DI) technology can improve the control precision of the in-cylinder mixing and combustion process and effectively avoid volumetric efficiency reduction in a compressed natural gas (CNG) engine, which has been a tendency. Ho...

This study analyzes the geochemical characteristics of natural gas composition, carbon isotope, and light hydrocarbon in the eastern belt around the Penyijingxi sag of the Junggar Basin. The result shows the that natural gas content is dominated by a...

A novel experimental method for the lateral mixing of binary solids in bubbling fluidized beds was developed based on the capacitance probe technique. The evolutions of local mixing ratios in a fluidized bed which can be assumed as one mixing cell we...

Anaerobic membrane bioreactors (AnMBRs) require biogas recycling to stir the mixed liquid and flush particles away from the membrane surfaces for stable operation. With the fixed gas cycling rate, gas diffuser configuration is an important factor tha...

In order to address the problem of sulfur gas and other odors released in the process of using sewage sludge as a construction material, this study prepared multiscale composite particles with a “large scale-medium scale-small scale-micro scale...

In the middle and late stages of offshore carbon-rich gas reservoir development, insufficient reservoir energy poses significant challenges and difficulty in improving gas recovery. Injecting CO2 back into the reservoir is a promising development app...

In the production process of electrical steel, with respect to the industrial RH (Ruhrstahl–Heraeus), the steel producers must balance the high-circulation flow rate (operating efficiency) and the frequent cleaning of cold steel in the vacuum c...

In this paper, we investigate the effect of Pd thickness and heat treatment on Pd/Ni/Au/p-GaN metal contacts. The as-deposited samples exhibit a smooth morphology and non-linear I–V characteristics. Heat treatment in a N2 atmosphere leads to de...

Numerous combustion applications are concerned with the stabilization of diffusion flames formed by injecting gaseous fuels into a co-flowing stream containing an oxidizer. The smooth operation of these devices depends on the attachment and lift-off...

In recent years, the C4F7N mixed gas has attracted considerable attention for its outstanding insulation and arc-extinguishing capabilities, positioning it as a potential substitute for sulfur hexafluoride, SF6. However, there remains a limited under...

Based on a multi-gas solution-diffusion problem for a dense symmetrical membrane this paper presents a transient theory of a planar, membrane-based sensor cell for measuring gas from both initial conditions: dynamic and thermodynamic equilibrium. Usi...

In the petroleum industry, multiphase transport pumps are a crucial technology for petroleum extraction. Therefore, the pressure fluctuation and internal-flow characteristics of multiphase transport pumps with different inlet-gas-volume fractions (IG...

Arc brazing is an alternative joining technology well-suited for processing thermally sensitive materials and to produce mixed material connections. Due to the technological similarities of gas metal arc brazing to gas metal arc welding, it can be as...