scholarly journals A Review of Reactor Designs for Hydrogen Storage in Clathrate Hydrates

2021 ◽  
Vol 11 (2) ◽  
pp. 469
Author(s):  
Mohammad Reza Ghaani ◽  
Judith M. Schicks ◽  
Niall J. English
Keyword(s):  
Hydrogen Storage ◽  
Large Scale ◽  
Three Dimensional ◽  
Pilot Scale ◽  
Clathrate Hydrates ◽  
Dimensional Network ◽  
Future Challenges ◽  
Industrial Use ◽  
Pilot Scale Reactor ◽  
And Storage

Clathrate hydrates are ice-like, crystalline solids, composed of a three-dimensional network of hydrogen bonded water molecules that confines gas molecules in well-defined cavities that can store gases as a solid solution. Ideally, hydrogen hydrates can store hydrogen with a maximum theoretical capacity of about 5.4 wt%. However, the pressures necessary for the formation of such a hydrogen hydrate are 180–220 MPa and therefore too high for large-scale plants and industrial use. Thus, since the early 1990s, there have been numerous studies to optimize pressure and temperature conditions for hydrogen formation and storage and to develop a proper reactor type via optimisation of the heat and mass transfer to maximise hydrate storage capacity in the resulting hydrate phase. So far, the construction of the reactor has been developed for small, sub-litre scale; and indeed, many attempts were reported for pilot-scale reactor design, on the multiple-litre scale and larger. The purpose of this review article is to compile and summarise this knowledge in a single article and to highlight hydrogen-storage prospects and future challenges.

Carbon Capture, Utilization, and Storage: An Update

SPE Journal ◽  
2018 ◽  
Vol 23 (06) ◽  
pp. 2444-2455 ◽  
Author(s):  
Franklin M. Orr
Keyword(s):  
Oil Recovery ◽  
Carbon Capture ◽  
Large Scale ◽  
New Technologies ◽  
Research Effort ◽  
Pilot Scale ◽  
Project Finance ◽  
Separation Processes ◽  
Carbon Dioxide Co2 ◽  
And Storage

Summary Recent progress in carbon capture, utilization, and storage (CCUS) is reviewed. Considerable research effort has gone into carbon dioxide (CO2) capture, with many promising separation processes in various stages of development, but only a few have been tested at commercial scale, and considerable additional development will be required to determine competitiveness of new technologies. Processes for direct capture of CO2 from the air are also under development and are starting to be tested at pilot scale. Transportation of CO2 to storage sites by pipeline is well-established, though substantially more pipeline capacity will be required if CCUS is to be undertaken at a large scale. Considerable experience has now been built up in enhanced-oil-recovery (EOR) operations, which have been under way since the 1970s. Storage in deep saline aquifers has also been achieved at scale. Recent large-scale projects that capture and store CO2 are described, as are current and potential future markets for CO2. Potential effects of changes in the US tax code Section 45Q on those markets are summarized. Future deployment of CCUS will depend more on cost reductions for CO2 separations, development of new markets for CO2, and the complexities of project finance than on technical issues associated with storage of CO2 in the subsurface.

A FORMULATION OF THE FAST MULTIPOLE BOUNDARY ELEMENT METHOD (FMBEM) FOR ACOUSTIC RADIATION AND SCATTERING FROM THREE-DIMENSIONAL STRUCTURES

2008 ◽  
Vol 16 (02) ◽  
pp. 303-320 ◽  
Author(s):  
Z.-S. CHEN ◽  
H. WAUBKE ◽  
W. KREUZER
Keyword(s):  
Boundary Element Method ◽  
Boundary Element ◽  
Large Scale ◽  
Acoustic Radiation ◽  
Three Dimensional ◽  
Efficient Computation ◽  
Fast Multipole ◽  
Head Related Transfer Function ◽  
And Storage ◽  
Element Method

Compared to the traditional boundary element method (BEM), the single level fast multipole boundary element method (SLFMBEM) or the multilevel fast multipole boundary element method (MLFMBEM) reduces the computational complexity of a job from O(n2) to O(n3/2) or O(n log 2n), respectively with n being the number of unknowns; this means a dramatical reduction in terms of CPU-time and storage requirement. Large scale problems, unsolvable with the traditional BEM, can be solved by using the FMBEM. In this paper, the traditional BEM, SLFMBEM, and MLFMBEM are formulated within the framework of the Burton–Miller Collocation BEM for acoustic radiation and scattering from 3D structures. Attention is especially paid to the practical aspects of the method in order to get a reliable and efficient computation code. The performance of the method is tested with practical examples, including one for computing the head-related transfer function (HRTF) between 1000 and 18 000 Hz.

Development of Mucoadhesive Buccal Drug Delivery System of Propranolol Hydrochloride Using Aster ericoides Mucilage

2020 ◽  
Vol 10 (2) ◽  
pp. 133-148
Author(s):  
Ankaj Kaundal ◽  
Pravin Kumar ◽  
Rajendra Awasthi ◽  
Giriraj T. Kulkarni
Keyword(s):  
Buccal Cavity ◽  
Three Dimensional ◽  
Hot Water ◽  
Fickian Diffusion ◽  
Aster Ericoides ◽  
Dimensional Network ◽  
Buccal Tablet ◽  
Significant Difference ◽  
Volunteer Group

Aim: The study was aimed to develop mucoadhesive buccal tablets using Aster ericoides leaves mucilage. Background : Mucilages are naturally occurring high-molecular-weight polyuronides, which have been extensively studied for their application in different pharmaceutical dosage forms. Objective: The objective of the present research was to establish the mucilage isolated from the leaves of Aster ericoides as an excipient for the formulation of the mucoadhesive buccal tablet. Method: The mucilage was isolated from the leaves of Aster ericoides by maceration, precipitated with acetone and characterized. Tablets were prepared using wet granulation technique and evaluated for various official tests. Results: The mucilage was found to be non-toxic on A-431 and Vero cell lines. It was insoluble but swellable in cold and hot water. The results indicate that mucilage can form a three-dimensional network. The pH of the mucilage (6.82 ± 0.13) indicated that it might be non-irritant to the buccal cavity. The mucilage was found to be free from microbes. The release of drug was by Fickian diffusion. The in vivo buccal tablet acceptance was 80%. No significant difference between the diastolic blood pressure of standard and Aster tablets treated volunteer group was recorded. Conclusion: The mucilage was found to be non-toxic on A-431 and Vero cell lines. It was insoluble but swellable in cold and hot water. The results indicate that mucilage can form a three-dimensional network. The pH of the mucilage (6.82 ± 0.13) indicated that it might be non-irritant to the buccal cavity. The mucilage was found to be free from microbes. The release of drug was by Fickian diffusion. The in vivo buccal tablet acceptance was 80%. No significant difference between the diastolic blood pressure of standard and Aster tablets treated volunteer group was recorded. Other: However, to prove the potency of the polymer, in vivo bioavailability studies in human volunteers are needed along with chronic toxicity studies in suitable animal models.

scholarly journals Crystal structure of K[Hg(SCN)3] – a redetermination

2014 ◽  
Vol 70 (9) ◽  
pp. i46-i46 ◽  
Author(s):  
Matthias Weil ◽  
Thomas Häusler
Keyword(s):  
Crystal Structure ◽  
Room Temperature ◽  
Three Dimensional ◽  
Lattice Parameters ◽  
Bond Lengths ◽  
Dimensional Network ◽  
Anisotropic Displacement Parameters ◽  
Precision And Accuracy ◽  
Standard Deviations ◽  
Atomic Coordinates

The crystal structure of the room-temperature modification of K[Hg(SCN)3], potassium trithiocyanatomercurate(II), was redetermined based on modern CCD data. In comparison with the previous report [Zhdanov & Sanadze (1952).Zh. Fiz. Khim.26, 469–478], reliability factors, standard deviations of lattice parameters and atomic coordinates, as well as anisotropic displacement parameters, were revealed for all atoms. The higher precision and accuracy of the model is, for example, reflected by the Hg—S bond lengths of 2.3954 (11), 2.4481 (8) and 2.7653 (6) Å in comparison with values of 2.24, 2.43 and 2.77 Å. All atoms in the crystal structure are located on mirror planes. The Hg2+cation is surrounded by four S atoms in a seesaw shape [S—Hg—S angles range from 94.65 (2) to 154.06 (3)°]. The HgS4polyhedra share a common S atom, building up chains extending parallel to [010]. All S atoms of the resulting1∞[HgS2/1S2/2] chains are also part of SCN−anions that link these chains with the K+cations into a three-dimensional network. The K—N bond lengths of the distorted KN7polyhedra lie between 2.926 (2) and 3.051 (3) Å.

scholarly journals Construction of the Cellulose Nanofibers (CNFs) Aerogel Loading TiO2 NPs and Its Application in Disposal of Organic Pollutants

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1841
Author(s):  
Kang Li ◽  
Xuejie Zhang ◽  
Yan Qin ◽  
Ying Li
Keyword(s):  
High Efficiency ◽  
Sol Gel ◽  
Cellulose Nanofibers ◽  
Three Dimensional ◽  
Good Mechanical Property ◽  
Polar Groups ◽  
Dimensional Network ◽  
Natural Polysaccharide ◽  
Valuable Method ◽  
Adsorption Capability

Aerogels have been widely used in the adsorption of pollutants because of their large specific surface area. As an environmentally friendly natural polysaccharide, cellulose is a good candidate for the preparation of aerogels due to its wide sources and abundant polar groups. In this paper, an approach to construct cellulose nanofibers aerogels with both the good mechanical property and the high pollutants adsorption capability through chemical crosslinking was explored. On this basis, TiO2 nanoparticles were loaded on the aerogel through the sol-gel method followed by the hydrothermal method, thereby the enriched pollutants in the aerogel could be degraded synchronously. The chemical cross-linker not only helps build the three-dimensional network structure of aerogels, but also provides loading sites for TiO2. The degradation efficiency of pollutants by the TiO2@CNF Aerogel can reach more than 90% after 4 h, and the efficiency is still more than 70% after five cycles. The prepared TiO2@CNF Aerogels have high potential in the field of environmental management, because of the high efficiency of treating organic pollutes and the sustainability of the materials. The work also provides a choice for the functional utilization of cellulose, offering a valuable method to utilize the large amount of cellulose in nature.

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