scholarly journals A Review on the Technology of Size Reduction Equipment

2020 ◽  
Vol 13 (1) ◽  
pp. 48-54
Author(s):  
A. Kumar ◽  
R. Yedhu Krishnan
Keyword(s):  
Surface Area ◽  
Mechanical Force ◽  
Size Reduction ◽  
Unit Operation ◽  
Widespread Application ◽  
Consequent Reduction

Size reduction or comminution is among the most comprehensively used unit operation of widespread application in chemical and other related industries. Subjugation of the materials to stress and consequent reduction in the size of larger solid units into smaller or finer unit masses is called as comminution. The transmission of stress is through the application of mechanical force to the larger solid unit. The most common methods utilized in industries include the use of crushers and mills. The concept of comminution is not novel as it has been utilized by man since time immemorial. Even though many different size reduction machines are available currently the key is the knowledge on the properties of the material to be processed. Size reduction offers advantages like increased surface area and separation of entrapped components.

scholarly journals Development of A Novel Corrugated Polyvinylidene difluoride Membrane via Improved Imprinting Technique for Membrane Distillation

Polymers ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 865 ◽  
Author(s):  
Normi Izati Mat Nawi ◽  
Muhammad Roil Bilad ◽  
Nurazrina Zolkhiflee ◽  
Nik Abdul Hadi Nordin ◽  
Woei Jye Lau ◽  
...  
Keyword(s):  
Surface Area ◽  
Membrane Surface ◽  
Water Flux ◽  
Cross Flow ◽  
Membrane Distillation ◽  
Effective Surface Area ◽  
Effective Surface ◽  
Widespread Application ◽  
Polyvinylidene Difluoride ◽  
Term Operation

Membrane distillation (MD) is an attractive technology for desalination, mainly because its performance that is almost independent of feed solute concentration as opposed to the reverse osmosis process. However, its widespread application is still limited by the low water flux, low wetting resistance and high scaling vulnerability. This study focuses on addressing those limitations by developing a novel corrugated polyvinylidene difluoride (PVDF) membrane via an improved imprinting technique for MD. Corrugations on the membrane surface are designed to offer an effective surface area and at the same time act as a turbulence promoter to induce hydrodynamic by reducing temperature polarization. Results show that imprinting of spacer could help to induce surface corrugation. Pore defect could be minimized by employing a dual layer membrane. In short term run experiment, the corrugated membrane shows a flux of 23.1 Lm−2h−1 and a salt rejection of >99%, higher than the referenced flat membrane (flux of 18.0 Lm−2h−1 and similar rejection). The flux advantage can be ascribed by the larger effective surface area of the membrane coupled with larger pore size. The flux advantage could be maintained in the long-term operation of 50 h at a value of 8.6 Lm−2h−1. However, the flux performance slightly deteriorates over time mainly due to wetting and scaling. An attempt to overcome this limitation should be a focus of the future study, especially by exploring the role of cross-flow velocity in combination with the corrugated surface in inducing local mixing and enhancing system performance.

scholarly journals Synopsis of Factors Affecting Hydrogen Storage in Biomass-Derived Activated Carbons

2021 ◽  
Vol 13 (4) ◽  
pp. 1947
Author(s):  
Al Ibtida Sultana ◽  
Nepu Saha ◽  
M. Toufiq Reza
Keyword(s):  
Surface Area ◽  
Storage Temperature ◽  
Activated Carbons ◽  
Energy Content ◽  
High Surface ◽  
High Energy ◽  
Heat Of Adsorption ◽  
Morphological Properties ◽  
Potential Cost ◽  
Widespread Application

Hydrogen (H2) is largely regarded as a potential cost-efficient clean fuel primarily due to its beneficial properties, such as its high energy content and sustainability. With the rising demand for H2 in the past decades and its favorable characteristics as an energy carrier, the escalating USA consumption of pure H2 can be projected to reach 63 million tons by 2050. Despite the tremendous potential of H2 generation and its widespread application, transportation and storage of H2 have remained the major challenges of a sustainable H2 economy. Various efforts have been undertaken by storing H2 in activated carbons, metal organic frameworks (MOFs), covalent organic frameworks (COFs), etc. Recently, the literature has been stressing the need to develop biomass-based activated carbons as an effective H2 storage material, as these are inexpensive adsorbents with tunable chemical, mechanical, and morphological properties. This article reviews the current research trends and perspectives on the role of various properties of biomass-based activated carbons on its H2 uptake capacity. The critical aspects of the governing factors of H2 storage, namely, the surface morphology (specific surface area, pore volume, and pore size distribution), surface functionality (heteroatom and functional groups), physical condition of H2 storage (temperature and pressure), and thermodynamic properties (heat of adsorption and desorption), are discussed. A comprehensive survey of the literature showed that an “ideal” biomass-based activated carbon sorbent with a micropore size typically below 10 Å, micropore volume greater than 1.5 cm3/g, and high surface area of 4000 m2/g or more may help in substantial gravimetric H2 uptake of >10 wt% at cryogenic conditions (−196 °C), as smaller pores benefit by stronger physisorption due to the high heat of adsorption.

scholarly journals Spectroscopic study on peculiarities of fumed silica hydridesilylation with triethoxysilane under fluidized bed conditions

2021 ◽  
Vol 12 (4) ◽  
pp. 314-325
Author(s):  
P. O. Kuzema ◽  
◽  
A. V. Korobeinyk ◽  
V. A. Tertykh ◽  
◽  
...  
Keyword(s):  
Fluidized Bed ◽  
Surface Area ◽  
Fumed Silica ◽  
Silica Surface ◽  
High Surface ◽  
Space Filling ◽  
Silica Sample ◽  
Widespread Application ◽  
Silanol Groups ◽  
Heating Mode

Fumed silica has found widespread application in industry due to variety of fascinating properties. Owing to its specific manufacturing process, it consists of finely dispersed particles and is featured with large specific surface area covered by profoundly reactive silanol groups which are available for chemical grafting. Spherical shape of fumed silica particles and lacking porosity provides a space-filling structure. These characteristics implement the fume silica’s utilization as high-surface-area carriers for various catalysts, i.e. metallic nanometer-sized particles, organic moieties, etc. Currently a great attention is called to on-surface grafting to improve the silica-based carrier. Most of research is carried out in area of liquid phase chemistry involving an abundance of expensive and often toxic solvents while the space-filling properties of silica are favoring reactions in fluidized bed conditions. In current research fumed silica (A-300) was a subject for hydridesilylation with triethoxysilane under fluidized bed conditions. In all synthesis reported in current research the insignificant amount of solvent (1.00 wt. % of the amount used in typical wet-chemical modifications method) was spent for the silica surface silylation. While the mass ratio of silica/TES was kept constant, other conditions, i.e. solvent/catalyst presence, surface pretreatment, additional treatment with water, and the fluidized bed heating mode have been varied. FTIR spectroscopy revealed the interaction between groups of triethoxysilane and silica surface silanol groups and demonstrated the effect of modification conditions on the density of the hydridesilyl groups coverage. The results of FTIR spectroscopic studies have confirmed the presence of grafted silicon hydride groups on the surface of modified silica, as well as the presence of ethoxy and/or silanol groups – either intact or formed due to hydrolysis of the ethoxy groups. Titrimetric and spectrophotometric analysis was performed to estimate the concentration of grafted SiH groups (in all samples prepared under fluidized bed conditions their concentration ranged within about 0.28–0.55 mmol/g as dependent on the reaction conditions). Other important aspects of fluidization such as the presence of solvent and/or hydrolyzing agent, bed heating mode and the effect of the silica sample thermal pre-treatment are also discussed.

Modeling Size Reduction and Fractionation for Cellulosic Feedstock

2015 ◽  
pp. 1-26
Author(s):  
Ladan J. Naimi ◽  
Shahab Sokhansanj ◽  
Xiaotao T. Bi ◽  
C. Jim Lim ◽  
Anthony Ka-pong Lau ◽  
...  
Keyword(s):  
Renewable Energy ◽  
Surface Area ◽  
Material Properties ◽  
Woody Biomass ◽  
Size Reduction ◽  
Biofuel Production ◽  
Unit Operations ◽  
Feedstock Preparation ◽  
Cellulosic Feedstock

Biomass has attracted attention as a source of renewable energy. It is available in different forms such as lignocellulosic stalks of herbaceous and woody biomass. These forms of biomass should be prepared to go through bioconversion process or biofuel production. One of the major unit operations for preparation is size reduction, which increases the surface area available and breaks the structure of biomass. Size reduction is energy intensive and an expensive step of feedstock preparation. The characteristics of ground particles are the result of interactions between material properties and the modes of size reduction like shear, impact, and attrition. The fundamentals of size reduction of fibrous biomass are not well understood. This chapter summarizes the latest studies on modeling of size reduction of lignocellulosic and woody biomass.

scholarly journals One-Pot Decoration of Cupric Oxide on Activated Carbon Fibers Mediated by Polydopamine for Bacterial Growth Inhibition

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1158
Author(s):  
Hangil Moon ◽  
Young-Chul Lee ◽  
Jaehyun Hur
Keyword(s):  
Antimicrobial Activity ◽  
Activated Carbon ◽  
Surface Area ◽  
Bacterial Growth ◽  
Photoelectron Spectroscopy ◽  
Cupric Oxide ◽  
Activated Carbon Fiber ◽  
One Pot ◽  
Widespread Application ◽  
X Ray

Despite the widespread application of activated carbon fiber (ACF) filters in air cleaning owing to their high surface area and low price, they have certain limitations in that they facilitate bacterial growth upon prolonged use as ACF filters can provide favorable conditions for bacterial survival. The deposition of cupric oxide (CuO) on ACFs can be an effective way of resolving this problem because CuO can inhibit the proliferation of bacteria owing to its antimicrobial properties. However, finding a new method that allows the simple and uniform coating of CuO on ACF filters is challenging. Here, we demonstrate one-pot CuO deposition mediated by polydopamine (PD) to realize an ACF filter with antimicrobial activity. Scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS) analyses reveal that CuO and PD are uniformly deposited on the ACF surface. The amount of CuO formed on the ACFs is measured by thermogravimetric analysis (TGA). Finally, the changes in surface area, pressure drop, and antimicrobial activity after coating PD-CuO on the ACFs are evaluated. The use of PD-CuO on the ACFs effectively suppresses the growth of bacteria and enhances the mechanical properties without significantly sacrificing the original characteristics of the ACF filter.

Analysis of particle size reduction on overall surface area and enzymatic hydrolysis yield of corn stover

2014 ◽  
Vol 38 (1) ◽  
pp. 149-154 ◽  
Author(s):  
Hanjie Li ◽  
Chenlin Ye ◽  
Ke Liu ◽  
Hanqi Gu ◽  
Weitao Du ◽  
...  
Keyword(s):  
Particle Size ◽  
Enzymatic Hydrolysis ◽  
Surface Area ◽  
Corn Stover ◽  
Size Reduction ◽  
Particle Size Reduction ◽  
Hydrolysis Yield

scholarly journals The Effect of Wet Milling and Cryogenic Milling on the Structure and Physicochemical Properties of Wheat Bran

Foods ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1755
Author(s):  
Yamina De Bondt ◽  
Inge Liberloo ◽  
Chiara Roye ◽  
Erich J. Windhab ◽  
Lisa Lamothe ◽  
...  
Keyword(s):  
Particle Size ◽  
Physicochemical Properties ◽  
Surface Area ◽  
Wheat Bran ◽  
Large Scale ◽  
Size Reduction ◽  
Laboratory Scale ◽  
Wet Milling ◽  
Particle Size Reduction ◽  
Cryogenic Milling

Wheat bran consumption is associated with several health benefits, but its incorporation into food products remains low because of sensory and technofunctional issues. Besides, its full beneficial potential is probably not achieved because of its recalcitrant nature and inaccessible structure. Particle size reduction can affect both technofunctional and nutrition-related properties. Therefore, in this study, wet milling and cryogenic milling, two techniques that showed potential for extreme particle size reduction, were used. The effect of the milling techniques, performed on laboratory and large scale, was evaluated on the structure and physicochemical properties of wheat bran. With a median particle size (d50) of 6 µm, the smallest particle size was achieved with cryogenic milling on a laboratory scale. Cryogenic milling on a large scale and wet milling on laboratory and large scale resulted in a particle size reduction to a d50 of 28–38 µm. In the milled samples, the wheat bran structure was broken down, and almost all cells were opened. Wet milling on laboratory and large scale resulted in bran with a more porous structure, a larger surface area and a higher capacity for binding water compared to cryogenic milling on a large scale. The extensive particle size reduction by cryogenic milling on a laboratory scale resulted in wheat bran with the highest surface area and strong water retention capacity. Endogenous enzyme activity and mechanical breakdown during the different milling procedures resulted in different extents of breakdown of starch, sucrose, β-glucan, arabinoxylan and phytate. Therefore, the diverse impact of the milling techniques on the physicochemical properties of wheat bran could be used to target different technofunctional and health-related properties.

Experimental Study of Evaporator Surface Area Influence on a Closed Loop Pulsating Heat Pipe Performance

2012 ◽  
Author(s):  
Mohammad Hadi Tabatabaee ◽  
Mahshid Mohammadi ◽  
Mohammad Behshad Shafii
Keyword(s):  
Experimental Study ◽  
Heat Source ◽  
Heat Pipe ◽  
Flow Regime ◽  
Surface Area ◽  
Closed Loop ◽  
Heat Removal ◽  
Working Fluid ◽  
Pulsating Heat Pipe ◽  
Widespread Application

Pulsating Heat Pipes are an effective mean for heat removal with the potential for a widespread application in electronic packaging. An experimental study a Closed Loop Pulsating Heat Pipe (CLPHP) constructed of copper tubes formed into four meandering turns is presented. Once configured in a vertical orientation the lower portion of the CLPHP comes in contact with a heat source (called the evaporator) from which it will remove heat through the pulsating action of the two-phase mixture contained within the initially evacuated copper tubes eventually transfer the heat to a heat sink (known as the condenser). Heat fluxes can be measured using temperature data gathered from experiments. Thermocouples connected to the copper tubes at several locations provide this data. Experiments were conducted using deionized water as the working fluid. The surface area of the tubing which comes in contact with the heat source at the evaporator affects the heat removal rates. This effect was studied by varying the surface area in contact with the heat source while providing the same power input. Experiments were conducted using different filling ratios of working fluid (20–70%) for each case. The heat source (heating elements wound around the tubes) was supplied with different power inputs ranging from 10 to 40 W. Results indicate the surface area affects the pulsating action differently for each configuration because of its dependency on the flow regime. These results are presented for each flow regime. The results can be used to optimize the CLPHP according to the flow regime which it will be working in.

Preparation and characterisation of vanadium pentoxide supported rhodium catalyst

1988 ◽  
Vol 46 ◽  
pp. 946-947
Author(s):  
A. Legrouri
Keyword(s):  
Aqueous Solution ◽  
Thermal Decomposition ◽  
Physicochemical Properties ◽  
Surface Area ◽  
Vanadium Pentoxide ◽  
High Purity ◽  
Gas Adsorption ◽  
Rhodium Catalyst ◽  
Optical Methods ◽  
Reducible Oxides

The industrial importance of metal catalysts supported on reducible oxides has stimulated considerable interest during the last few years. This presentation reports on the study of the physicochemical properties of metallic rhodium supported on vanadium pentoxide (Rh/V2O5). Electron optical methods, in conjunction with other techniques, were used to characterise the catalyst before its use in the hydrogenolysis of butane; a reaction for which Rh metal is known to be among the most active catalysts.V2O5 powder was prepared by thermal decomposition of high purity ammonium metavanadate in air at 400 °C for 2 hours. Previous studies of the microstructure of this compound, by HREM, SEM and gas adsorption, showed it to be non— porous with a very low surface area of 6m2/g3. The metal loading of the catalyst used was lwt%Rh on V2Q5. It was prepared by wet impregnating the support with an aqueous solution of RhCI3.3H2O.

Cell morphology, volume, and surface area determinations from multilevel contouring within HVEM micrographs of serial sections and whole-cell mounts

1987 ◽  
Vol 45 ◽  
pp. 588-589
Author(s):  
M. Marko ◽  
A. Leith ◽  
D. Parsons
Keyword(s):  
Surface Area ◽  
Electron Micrographs ◽  
Cell Morphology ◽  
Individual Variation ◽  
Serial Section ◽  
Stereo Pair ◽  
Complex Structures ◽  
Serial Sections ◽  
Surface Areas ◽  
Computer Based

The use of serial sections and computer-based 3-D reconstruction techniques affords an opportunity not only to visualize the shape and distribution of the structures being studied, but also to determine their volumes and surface areas. Up until now, this has been done using serial ultrathin sections.The serial-section approach differs from the stereo logical methods of Weibel in that it is based on the Information from a set of single, complete cells (or organelles) rather than on a random 2-dimensional sampling of a population of cells. Because of this, it can more easily provide absolute values of volume and surface area, especially for highly-complex structures. It also allows study of individual variation among the cells, and study of structures which occur only infrequently.We have developed a system for 3-D reconstruction of objects from stereo-pair electron micrographs of thick specimens.

Sign in / Sign up

Export Citation Format

Share Document