scholarly journals One-step ethylene production from a four-component gas mixture by a single physisorbent

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jian-Wei Cao ◽  
Soumya Mukherjee ◽  
Tony Pham ◽  
Yu Wang ◽  
Teng Wang ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Binding Sites ◽  
Selective Adsorption ◽  
Diphenyl Ether ◽  
Gas Mixtures ◽  
Single Step ◽  
Gas Mixture ◽  
One Step ◽  
Breakthrough Experiments ◽  
Insight Into

AbstractOne-step adsorptive purification of ethylene (C2H4) from four-component gas mixtures comprising acetylene (C2H2), ethylene (C2H4), ethane (C2H6) and carbon dioxide (CO2) is an unmet challenge in the area of commodity purification. Herein, we report that the ultramicroporous sorbent Zn-atz-oba (H2oba = 4,4-dicarboxyl diphenyl ether; Hatz = 3-amino-1,2,4-triazole) enables selective adsorption of C2H2, C2H6 and CO2 over C2H4 thanks to the binding sites that lie in its undulating pores. Molecular simulations provide insight into the binding sites in Zn-atz-oba that are responsible for coadsorption of C2H2, C2H6 and CO2 over C2H4. Dynamic breakthrough experiments demonstrate that the selective binding exhibited by Zn-atz-oba can produce polymer-grade purity (>99.95%) C2H4 from binary (1:1 for C2H4/C2H6), ternary (1:1:1 for C2H2/C2H4/C2H6) and quaternary (1:1:1:1 for C2H2/C2H4/C2H6/CO2) gas mixtures in a single step.

scholarly journals Molecular Simulations of CO2/CH4, CO2/N2 and N2/CH4 Binary Mixed Hydrates

2021 ◽  
Vol 83 (3) ◽  
pp. 372-378
Author(s):  
A. A. Sizova ◽  
S. A. Grintsevich ◽  
M. A. Kochurin ◽  
V. V. Sizov ◽  
E. N. Brodskaya
Keyword(s):  
Carbon Dioxide ◽  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Gas Hydrates ◽  
Molecular Simulations ◽  
Gas Mixtures ◽  
Gas Mixture ◽  
Grand Canonical Monte Carlo ◽  
Multicomponent Gas ◽  
Grand Canonical

Abstract Grand canonical Monte Carlo simulations were performed to study the occupancy of structure I multicomponent gas hydrates by CO2/CH4, CO2/N2, and N2/CH4 binary gas mixtures with various compositions at a temperature of 270 K and pressures up to 70 atm. The presence of nitrogen in the gas mixture allows for an increase of both the hydrate framework selectivity to CO2 and the amount of carbon dioxide encapsulated in hydrate cages, as compared to the CO2/CH4 hydrate. Despite the selectivity to CH4 molecules demonstrated by N2/CH4 hydrate, nitrogen can compete with methane if the gas mixture contains at least 70% of N2.

scholarly journals Dobór wydajności gazów propan-butan dodawanych w celu wspomagania efektywnego spalania gazu ziemnego niskometanowego z użyciem flary

Nafta-Gaz ◽  
2021 ◽  
Vol 77 (1) ◽  
pp. 26-32
Author(s):  
Paweł Budak ◽  
◽  
Tadeusz Szpunar ◽  
Keyword(s):  
Carbon Dioxide ◽  
Flow Rate ◽  
Gas Mixtures ◽  
Gas Mixture ◽  
Gas Reservoirs ◽  
Empirical Relationships ◽  
Complete Combustion ◽  
Toxic Gases ◽  
Butane Mixture ◽  
Propane Butane

The paper discusses the problems related to the burning of gas mixtures containing flammable and non-flammable gases using a flare. Before being burned, such a gas mixture must be “enriched” with other flammable gases before it can be directed to the flare. In the case of some Polish gas reservoirs such as Cychry or Sulęcin, the composition of the gas mixture doesn’t make it possible to burn it using the flare because the content of inflammable components is too high and the gas mixture is inflammable. The gas from the reservoirs mentioned above contains above 90 percent of nitrogen and small percentages of flammable components. Sometimes, besides nitrogen, the gas mixture contains other inflammable gases like carbon dioxide, helium, and oxygen. Usually, the propane/butane is used for that purpose. The possibility of burning the gas mixture using the flare is particularly important if the toxic gases are present in the mixture – hydrogen sulfide in particular. The propane/butane gases are added to the stream of gas mixture meant for burning using a special appliance. The typical arrangement of a gas-burning installation (i.e. the flare) is shown and the destination of its components is discussed. The empirical formula is provided which allows us to recognize if the gas mixture is flammable or not. The composition of the gas mixture must be known to calculate the propane/butane flow rate, including percentages of flammable and inflammable components. The algorithm constructed for calculating the propane/butane flow rate is presented, which must be maintained to assure the flammability of the gas mixture destined for burning using the flare. The results of the calculations for four gas mixtures from the Polish gas reservoirs are provided. The presented method of determining the flammability of gas mixtures (or its inability to be burned) and the flow rate of the propane/butane mixture required for complete combustion is based on empirical relationships, which are provided in the paper and may be helpful in planning the assisted combustion of low methane gases (not suitable for further use) using a flare.

A microporous MOF with a polar pore surface exhibiting excellent selective adsorption of CO2 from CO2–N2 and CO2–CH4 gas mixtures with high CO2 loading

2017 ◽  
Vol 46 (44) ◽  
pp. 15280-15286 ◽  
Author(s):  
Arun Pal ◽  
Santanu Chand ◽  
Syed Meheboob Elahi ◽  
Madhab C. Das
Keyword(s):  
Flue Gas ◽  
Selective Adsorption ◽  
Landfill Gas ◽  
Gas Mixtures ◽  
Gas Mixture ◽  
Pore Surface ◽  
High Co2 ◽  
Selective Sorption ◽  
Adsorption Of Co2

A microporous MOF (IITKGP-5) with polar pore surface exhibits highly selective sorption of CO2 from flue gas as well as landfill gas mixture with IAST selectivity for 435.5 and 151.6 at 273 K/100 kPa respectively.

An Efficient Method for Modeling Radiative Transfer in Multicomponent Gas Mixtures With Soot

2000 ◽  
Vol 123 (3) ◽  
pp. 450-457 ◽  
Author(s):  
Vladimir P. Solovjov ◽  
Brent W. Webb
Keyword(s):  
Carbon Dioxide ◽  
Radiative Transfer ◽  
Narrow Band ◽  
Gas Mixtures ◽  
Distribution Functions ◽  
Individual Species ◽  
Gas Mixture ◽  
Weighted Sum ◽  
Multicomponent Gas ◽  
The Individual

An efficient approach for predicting radiative transfer in high temperature multicomponent gas mixtures with soot particles is presented. The method draws on the previously published multiplication approach for handling gas mixtures in the spectral line weighted-sum-of-gray-gases (SLW) model. In this method, the gas mixture is treated as a single gas whose absorption blackbody distribution function is calculated through the distribution functions of the individual species in the mixture. The soot is, in effect, treated as another gas in the mixture. Validation of the method is performed by comparison with line-by-line solutions for radiative transfer with mixtures of water vapor, carbon dioxide, and carbon monoxide with a range of soot loadings (volume fractions). Comparison is performed also with previously published statistical narrow band and classical weighted-sum-of-gray-gases solutions.

scholarly journals A crossover trial investigating the atmospheric content of improvised respirators

2021 ◽  
pp. 175114372098871
Author(s):  
Paul R Greig ◽  
Clarissa Carvalho ◽  
Suniel Ramessur ◽  
Jan Schumacher ◽  
Kariem El-Boghdadly
Keyword(s):  
Carbon Dioxide ◽  
Crossover Study ◽  
Crossover Trial ◽  
Gas Mixtures ◽  
Gas Mixture ◽  
Moisture Exchange ◽  
Carbon Dioxide Concentrations ◽  
Full Face ◽  
Heat And Moisture ◽  
Oxygen Concentrations

Introduction This study was designed to determine the respiratory safety of improvised respirators based on modified full-face snorkel masks, making comparisons with a purpose-designed mask Methods This is a prospective crossover study conducted on ten recruits. Volunteers wore snorkel masks mated to an anaesthetic heat and moisture exchange filter. The system was worn at rest then during exercise. Gases were sampled from the mask at 5-min intervals. Results The modified snorkel was satisfactory in seven participants. For three carbon dioxide concentrations were >1%. Two participants exposed to excessive CO2 also experienced oxygen concentrations <19%. All participants exposed to unsatisfactory gas mixtures were non-white. Conclusions Modifying snorkel masks changes the way that gases circulate through the system. These modifications increase the risk of rebreathing in some users, which may yield an unsafe gas mixture. These improvised masks cannot be recommended as a substitute for purpose-designed equipment.

Microbial Flora of Cod Fillets (Gadus morhua) Stored at 2°C in Different Mixtures of Carbon Dioxide and Nitrogen/Oxygen

1985 ◽  
Vol 48 (7) ◽  
pp. 585-589 ◽  
Author(s):  
INGA-MAJ STENSTROM
Keyword(s):  
Carbon Dioxide ◽  
Shelf Life ◽  
Gadus Morhua ◽  
Storage Period ◽  
Co2 Concentration ◽  
Gas Mixtures ◽  
Gas Mixture ◽  
Pseudomonas Spp ◽  
Fluorescent Pseudomonas ◽  
Lactobacillus Spp

Cod fillets were stored in different combinations of carbon dioxide and oxygen/nitrogen at 2°C and the development of the microflora was studied during storage. The shelf life, expressed as the time for the microflora to reach 1 × 106 CFU/g, successively increased as the CO2 concentration increased. No significant effects were noted whether oxygen or nitrogen was used together with CO2 to comprise the gas mixtures. In 100% CO2, the total aerobic count did not exceed 1 × 106 CFU/g during the storage period. The microflora of the fresh cod fillets consisted of Flavobacterium spp., Alteromonas putrefaciens, Moraxella-like organisms and Pseudomonas spp. After 6 d of storage in air, the total aerobic count had reached 5 × 107 CFU/g and the microflora was dominated by A. putrefaciens (62%) and non-fluorescent Pseudomonas spp. (28%). After 26 to 34 d of storage, Lactobacillus spp. and A. putrefaciens dominated the spoilage flora in the different gas mixtures and the total count amounted to 3 × 105 to 2 × 107 CFU/g. The ratio of Lactobacillus spp. at the termination of storage in the different gas mixtures increased in the order of air &lt;50%CO2/50%N2 &lt;50%CO2/50%O2 &lt;90%CO2/10%N2 &lt;100%CO2 &lt;90%CO2/10%O2, whereas the ratio of A. putrefaciens decreased in the same order. Considering the technical difficulties in using an atmosphere at 100% CO2 and the microflora developing during storage in the different gas mixtures, it is suggested that a suitable gas mixture for retail packages should be 50% CO2/50% O2.

Effect of Lipoprotein(a) and LDL on Plasminogen Binding to Extracellular Matrix and on Matrix-dependent Plasminogen Activation by Tissue Plasminogen Activator

1996 ◽  
Vol 75 (03) ◽  
pp. 497-502 ◽  
Author(s):  
Hadewijch L M Pekelharing ◽  
Henne A Kleinveld ◽  
Pieter F C.C.M Duif ◽  
Bonno N Bouma ◽  
Herman J M van Rijn
Keyword(s):  
Extracellular Matrix ◽  
Endothelial Cells ◽  
Plasminogen Activator ◽  
Binding Sites ◽  
Umbilical Vein ◽  
Single Step ◽  
Plasminogen Activation ◽  
Structural Homology ◽  
Tissue Plasminogen ◽  
Umbilical Vein Endothelial Cells

SummaryLp(a) is an LDL-like lipoprotein plus an additional apolipoprotein apo(a). Based on the structural homology of apo(a) with plasminogen, it is hypothesized that Lp(a) interferes with fibrinolysis. Extracellular matrix (ECM) produced by human umbilical vein endothelial cells was used to study the effect of Lp(a) and LDL on plasminogen binding and activation. Both lipoproteins were isolated from the same plasma in a single step. Plasminogen bound to ECM via its lysine binding sites. Lp(a) as well as LDL were capable of competing with plasminogen binding. The degree of inhibition was dependent on the lipoprotein donor as well as the ECM donor. When Lp(a) and LDL obtained from one donor were compared, Lp(a) was always a much more potent competitor. The effect of both lipoproteins on plasminogen binding was reflected in their effect on plasminogen activation. It is speculated that Lp(a) interacts with ECM via its LDL-like lipoprotein moiety as well as via its apo(a) moiety.

Synthesis of Polycycles and Oxacycles by Tandem Metathesis of endo–norbornene Derivatives

Synthesis ◽  
2021 ◽  
Author(s):  
Sambasivarao Kotha ◽  
Sunil Pulletikurti ◽  
Ambareen Fatma ◽  
gopal dhangar ◽  
gonna somu Naidu
Keyword(s):  
Natural Products ◽  
Metal Complex ◽  
Carbonyl Group ◽  
Single Step ◽  
Time Dependent ◽  
Computational Studies ◽  
Nmr Studies ◽  
Tricyclic Compounds ◽  
One Step ◽  
Norbornene Derivatives

Here, we have demonstrated that the presence of a carbonyl group at C7 position is preventing the olefin metathesis of endo-norbornene derivatives due to the complexation of the metal alkylidene. Time-dependent NMR studies showed the presence of new proton signals in the metal alkylidene region, which indicate the formation of metal complex with the carbonyl group of the substrate. These observations were further proved by ESI-MS analysis. Whereas, computational studies provided that the catalyst was interacting with the C7 carbonyl group and aligned perpendicular to that of norbornene olefin. Later, these endo-keto norbornene derivatives were reduced to hydroxyl derivatives diastereoselectively. Ring-rearrangement metathesis (RRM) of these hydroxyl derivatives, produced the [6/5/6], and [5/6/5] carbo-tricyclic cores of the natural products in one step. Whereas the RRM of O-allyl derivatives, delivered the oxa-tricyclic compounds in a single step with excellent yields.

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