| 1. |
- Abd Mutalib, Nor Fariza, et al.
(författare)
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A Prediction for the Conversion Performance of H2S to Elemental Sulfur in an Ionic-Liquid-Incorporated Transition Metal Using COSMO-RS
- 2022
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Ingår i: CHEMISTRY-SWITZERLAND. - : MDPI AG. - 2624-8549. ; 4:3, s. 811-826
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Tidskriftsartikel (refereegranskat)abstract
- In the present study, the conversion performance of hydrogen sulfide (H2S) to elemental sulfur in ionic-liquid-incorporated transition metals (ILTMs) is predicted using a conductor-like screening model for realistic solvents (COSMO-RS). The predictions were made via the establishment of a correlation between the conversion performance and solubility of H2S in ionic liquids (ILs). All molecules involved were optimized at the DFT/TZVP/M06 computational level and imported on the COSMOtherm program at equimolar conditions. For validation purposes, the solubility of ILs was predicted at 1 bar pressure. Simple regression analysis was used to establish a relationship between the solubility and conversion performance of H2S. The results indicate that the solubility prediction of ILs is accurate (R-2 = 93.40%) with a p-value of 0.0000000777. Additionally, the conversion performance is generally found to be dependent on the solubility value. Furthermore, 1-butyl-3-methylimidazolium chloride [bmim][Cl] was chosen as the base IL for incorporating the transition metal, owing to its solubility and selectivity to H2S. The solubility trend of ILTMs is found to follow the following order: [bmim][NiCl3] > [bmim][FeCl4] > [bmim][CoCl3] > [bmim][CuCl3]. According to the viscosity measurements of ILTMs, [bmim][NiCl3] and [bmim][FeCl4] exhibited the highest and lowest viscosity values, respectively. Therefore, [bmim][FeCl4] is a promising ILTM owing to its higher solubility and low viscosity for the application studied.
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| 2. |
- Idris, Alamin, et al.
(författare)
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A review on predictive tortuosity models for composite films in gas barrier applications
- 2022
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Ingår i: JCT Research. - : Springer. - 1547-0091 .- 2168-8028. ; 19, s. 699-716
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Tidskriftsartikel (refereegranskat)abstract
- Different types of impermeable fillers are usually incorporated into polymeric coating film to enhance the gas barrier properties. For instance, impermeable fillers are commonly used in barrier coating due to their larger surface, which in turn serve as barrier inclusions restricting the penetrant gas to diffuse through a longer tortuous pathway. Modeling gas transport in barrier coating can help determine the shelf-life of packaged food and reduce product development resources and time. In this paper, related tortuosity-based models corresponding to different filler geometries are outlined. This review emphasizes the emerging trends in modeling the tortuous pathway and the respective relative permeability model to predict the gas barrier performance in composite films used for barrier coating applications. We review models incorporating a range of factors, including different shapes, geometries, angular orientations, alignments, randomness in distribution, stacking, interspacing, and the polydispersity of fillers. The approaches employed to develop the tortuosity-based phenomenological models starting with simplified filler geometry and orientations to more complex morphological features of the composite films are elaborated.
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| 3. |
- Idris, Alamin, et al.
(författare)
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Grindability and abrasive behavior of coal blends : analysis and prediction
- 2022
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Ingår i: International Journal of Coal Preparation and Utilization. - : Taylor & Francis. - 1939-2699 .- 1939-2702. ; 42:4, s. 1143-1169
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Tidskriftsartikel (refereegranskat)abstract
- Low-grade coals are blended with high-quality coals to meet economic, environmental, and quality specifications. Hence, the grindability and abrasiveness of coal blends are crucial economic and operational parameters. This work evaluates, analyzes, and predicts the grindability and abrasive behavior of coal blends. Three binary coal blends with common low-grade coal were first prepared at various ratios. Blends 1 and 2 were composed of identical and similar ranks, whereas Blend 3 was composed of different ranks. The blends were analyzed using proximate, ultimate analyzers, and a Bomb calorimeter. The grindability and abrasive behavior of the blends were measured using Hardgrove grindability index (HGI) and Yancey, Geer, and Price methods, respectively. Further, the coarser (+75 mu m) and finer (-75 mu m) fractions of HGI experiment were characterized using proximate, ultimate and heating value analyses. The additivity of HGI values was observed for Blend 1 and Blend 2, whereas, the non-additive behavior was observed in Blend 3. Further, the blends' mineral matter contents and abrasiveness index were found to be additive. Several existing models were found to be inaccurate for HGI predictions. Therefore, a new cross-validated model using multi-linear regression was proposed. The model exhibited better HGI predictions of coal blends with a coefficient of determination R-2 = 0.9416.
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| 4. |
- Jamil, Asif, et al.
(författare)
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Novel CO2 Separation Membranes
- 2022
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Ingår i: Sustainable Carbon Capture. - Boca Raton : CRC Press. - 9781003162780 ; , s. 185-208
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Using membranes for CO2 capture has gained recent prominence in the global scientific community due to its lower capital cost and a quicker separation performance than the conventional separation methods. The membrane process features desirable properties, like compactness, energy efficiency, and environmental friendliness. Various polymeric and inorganic materials have been tested both as unique ingredients and blends to form CO2 separation membranes with a focus on increasing the performance but have had varying rates of success. For commercial viability, the membrane sector requires new techniques and testing materials to lower the cost of CO2 capture. Recently, thermally rearranged polymers, intrinsic microporous polymers, ionic liquid inclusion as fillers, and binary fillers have all emerged as novel trends, focusing on enhancing the working efficiency and sustainability of the membranes. This chapter explores the most recent advances in membrane technology and its future prospects as a sustainable solu ion towards carbon dioxide capture.
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| 5. |
- Joelsson, Tove, et al.
(författare)
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Fibre morphology affects the bonding and densification of hot-pressed thermomechanical pulp-based paper
- 2022
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Ingår i: Proceedings of the International Mechanical Pulping Conference. ; , s. 142-148
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- A successful way to increase the strength properties for pulps based on lignin-rich fibres is to compress the fibre structure at high temperature by means of hot-pressing technology. The fundamental knowledge of how the fi-bre morphology influences the mechanical properties when a paper sheet is hot-pressed is still scarce. Paper sheets based on thermomechanical pulp (TMP) produced with single disc and double disc refiners were compared. The effect of degree of refining was studied as well as the effect of fibre shapes by fractionating pulp with hydrocyclones. Additionally, the effect of fines was studied. All pulps were produced at the Holmen Bra-viken Mill, Norrköping, Sweden with Norway Spruce (Picea abies) as raw material. Handsheets (100 g/m2) with 62% ± 3 dryness were hot-pressed at temperatures up to 260°C at a pressure around 8MPa. The hot-press-ing increased both dry and wet strength for all pulps studied. This was true even for pulps with low fines con-tent and low refining energy. Even thick-walled fibres normally giving lower strength showed an increase of 100% when hot-pressed. In summary, hot-pressing technology can make it possible to use different TMPs to produce strong packaging materials for use in dry and wet conditions.
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| 6. |
- Khan, M. S., et al.
(författare)
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Effect of ammonium hydroxide-based ionic liquids' freezing point and hydrogen bonding on suppression temperature of different gas hydrates
- 2022
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Ingår i: Chemosphere. - : Elsevier BV. - 0045-6535 .- 1879-1298. ; 307
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Tidskriftsartikel (refereegranskat)abstract
- The study presents the effect of freezing point depression and hydrogen bonding energy interaction on four ammonium hydroxide-based ionic liquids (AHILs) of gas hydrate systems. The AHILs investigated are tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, and tetrabutylammonium hydroxide. The considered hydrate system includes methane (CH4), carbon dioxide (CO2), and three binary mixed gas hydrates (70-30 CO2 + CH4, 50-50 CO2 + CH4, 30–70 CO2 + CH4), which are often encountered in the flow assurance pipelines. The experimental temperature range is between 274.0 and 285.0 K, corresponding to pipeline pressures for different gas systems. The thermodynamic influence, i.e., average suppression temperature (ΔŦ) of the studied system, was reported for different mass concentrations (1, 5, and 10 wt%) and correlated with the freezing point depression and hydrogen bonding energy interaction of AHILs. The study also covers the structural impact of AHILs (in the form of alkyl chain variation) on the thermodynamic hydrate inhibition (THI) behaviour via freezing point and hydrogen bonding energy interactions. Findings revealed that the increased alkyl chain length of AHILs reduced the ΔŦ due to a decrease in hydrogen bonding ability. The highest THI inhibition (ΔŦ = 2.27 K) is attained from the lower alkyl chain AHIL, i.e., TMAOH (10 wt%) for the CO2 hydrate system. The freezing point depression of AHILs is a concentration-dependent phenomenon. Increased concentration of the AHILs in the system yielded lower freezing point temperature, positively influencing hydrate mitigation. Although the study provided the initial insight between the freezing point tendency and hydrogen bonding energies of AHILs on thermodynamic inhibition (ΔŦ). Based on the freezing point depression and hydrogen bonding energy interaction, a more generalized correlation should be developed to predict any potential ionic liquids regarded as promising hydrate inhibitors.
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| 7. |
- Mannan, Hafiz Abdul, et al.
(författare)
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Interfacial Tailoring of Polyether Sulfone-Modified Silica Mixed Matrix Membranes for CO2 Separation
- 2022
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Ingår i: Membranes. - : MDPI AG. - 2077-0375. ; 12:11
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Tidskriftsartikel (refereegranskat)abstract
- In this work, in situ polymerization of modified sol-gel silica in a polyether sulfone matrix is presented to control the interfacial defects in organic-inorganic composite membranes. Polyether sulfone polymer and modified silica are used as organic and inorganic components of mixed matrix membranes (MMM). The membranes were prepared with different loadings (2, 4, 6, and 8 wt.%) of modified and unmodified silica. The synthesized membranes were characterized using Field emission electron scanning microscopy, energy dispersive X-ray, Fourier transform infrared spectroscopy, thermogravimetric analyzer, and differential scanning calorimetry. The performance of the membranes was evaluated using a permeation cell set up at a relatively higher-pressure range (5-30 bar). The membranes appear to display ideal morphology with uniform distribution of particles, defect-free structure, and absence of interfacial defects such as voids and particle accumulations. Additionally, the CO2/CH4 selectivity of the membrane increased with the increase in the modified silica content. Further comparison of the performance indicates that PES/modified silica MMMs show a promising feature of commercially attractive membranes. Therefore, tailoring the interfacial morphology of the membrane results in enhanced properties and improved CO2 separation performance.
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| 8. |
- Rahman, Md Tauhidur, et al.
(författare)
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Effects of imidazolium- and ammonium-based ionic liquids on clay swelling : experimental and simulation approach
- 2022
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Ingår i: Journal of Petroleum Exploration and Production Technology. - : Springer Nature. - 2190-0558 .- 2190-0566. ; 12, s. 1841-1853
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Tidskriftsartikel (refereegranskat)abstract
- Water-based fracturing fluids without an inhibitor promote clay swelling, which eventually creates wellbore instability. Several ionic liquids (ILs) have been studied as swelling inhibitors in recent years. The cations of the ILs are crucial to the inhibitory mechanisms that take place during hydraulic fracturing. Individual studies were carried out on several ILs with various cations, with the most frequently found being ammonium and imidazolium cations. As a result, the goal of this study is to compare these two cations to find an effective swelling inhibitor. A comparison and evaluation of the clay swelling inhibitory properties of tetramethylammonium chloride (TMACl) and 1-ethyl-3-methylimidazolium chloride (EMIMCl) were conducted in this work. Their results were also compared to a conventional inhibitor, potassium chloride (KCl), to see which performed better. The linear swelling test and the rheology test were used to determine the inhibitory performance of these compounds. Zeta potential measurements, Fourier-transform infrared spectroscopy, and contact angle measurements were carried out to experimentally explain the inhibitory mechanisms. In addition, the COSMO-RS simulation was conducted to explain the inhibitory processes and provide support for the experimental findings. The findings of the linear swelling test revealed that the swelling was reduced by 23.40% and 15.66%, respectively, after the application of TMACl and EMIMCl. The adsorption of ILs on the negatively charged clay surfaces, neutralizing the charges, as well as the lowering of the surface hydrophilicity, aided in the improvement of the swelling inhibition performance.
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| 9. |
- Zhalehrajabi, Ehsan, et al.
(författare)
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Evaluation of hydrodynamic behavior of urea granules in a pseudo-2D fluidized bed using drag models and comparison with PIV technique
- 2022
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Ingår i: Powder Technology. - : Elsevier BV. - 0032-5910 .- 1873-328X. ; 406
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Tidskriftsartikel (refereegranskat)abstract
- The urea fluidized bed hydrodynamics were simulated using computational fluid dynamics (CFD) vs. image processing technique. To identify the suitable model, sensitivity analyses on time step, number of nodes, and drag force coefficient were performed, and accordingly, Gidaspow and Syamlal-O & PRIME;Brien drag models were selected to simulate the fluidized bed for -particles categorized under Geldart-D. The CFD data were validated against the determined particle velocity using an image processing technique. Results indicate that Gidaspow model predictions for particles velocity and granular temperature are in good agreement whereas the Syamlal-O'Brien model resulted in underestimated predictions. Further analysis using Gidaspow model, the particle velocity increased by 12.5%, when the air inlet velocity is increased from 2 to 3 m/s and decreased by 87.5% when the particle sizes are changed from 2 to 4 mm. Although the primary loading height and pressure showed no effect, but at high pressures, it is important to consider humidity to avoid the negative impact on the granulation performance.
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