scholarly journals Effect of Pristine Palygorskite Powders on Explosion Characteristics of Methane-Air Premixed Gas

Energies ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2496 ◽  
Author(s):  
Yimin Zhang ◽  
Yan Wang ◽  
Ligang Zheng ◽  
Tao Yang ◽  
Jianliang Gao ◽  
...  
Keyword(s):  
Flame Propagation ◽  
Low Cost ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Flame Propagation Velocity ◽  
Explosion Pressure ◽  
Pyrolysis Characteristics ◽  
Explosion Suppression ◽  
Adsorption Desorption ◽  
Methane Explosion

In this study, pristine palygorskite powders were used as the inhibition materials to suppress the explosion of methane-air premixed gas for the first time. The composition, porosity and pyrolysis characteristics of the powders were tested by X-ray diffraction (XRD), energy dispersive spectrometry (EDS), N2 adsorption-desorption and Thermogravimetry-differential scanning calorimetry (TG-DSC) techniques. The effects of pristine palygorskite powders concentration on the explosion pressure and the average velocity of flame propagation of the 9.5% methane-air premixed gas were tested by a 20 L spherical explosion system and a 5 L pipeline explosion system. The results indicated the pristine palygorskite powders possess a considerable suppression property on methane explosion. When the mass concentration of pristine palygorskite powders was 0.20 g·L−1, the max-pressure of methane explosion was decreased by 23.9%. The methane explosion flame propagation velocity was inhibited obviously. Owing to the excellent inhibitory performance and the advantage of low-cost and environmental harmlessness, pristine palygorskite powders are potential new materials for the application on gas explosion suppression.

scholarly journals Suppression Effects of Hydroxy Acid Modified Montmorillonite Powders on Methane Explosions

Energies ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 4068 ◽  
Author(s):  
Yan Wang ◽  
Hao Feng ◽  
Yimin Zhang ◽  
Chendi Lin ◽  
Ligang Zheng ◽  
...  
Keyword(s):  
Functional Groups ◽  
Gluconic Acid ◽  
Pressure Rise ◽  
Experimental System ◽  
Hydroxyl Groups ◽  
Scanning Calorimetry ◽  
Suppression Effect ◽  
Explosion Pressure ◽  
Pyrolysis Characteristics ◽  
Explosion Suppression

In this paper, montmorillonite inhibitors modified with polyhydroxy functional groups by gluconic acid (GA) were successfully prepared. The particle size distribution, composition, surface functional groups, and pyrolysis characteristics of the pure montmorillonite powders (Mt) and the gluconic acid modified powders (G-Mt) were analyzed by using a laser particle analyzer, X-ray diffraction (XRD), Fourier transform infrared (FTIR) and thermogravimetry–differential scanning calorimetry (TG-DSC), respectively. The suppression effect of Mt and G-Mt on the 9.5% methane–air premixed gas was tested in a 20 L spherical explosion device and a 5 L pipeline experimental system. The results show that G-Mt displays a much better suppression property than that of Mt. The optimal explosion suppression effect concentration of Mt or G-Mt powders is about 0.25 g·L−1. In this concentration, for G-Mt, the maximum explosion pressure declined by 26.7%, the maximum rate of pressure rise declined by 74.63%, and the time for the flame front to reach the top of the pipe was delayed by 242.5%. On the basis of the experimental data, the better suppression effect of G-Mt than Mt might be attributed to the presence of more hydroxyl groups on the surface.

Crystallization of Amorphous Cu49.7Ti31.8Zr11.3Ni7.2 Alloy

2016 ◽  
Vol 869 ◽  
pp. 464-469 ◽  
Author(s):  
Carlos Triveño Rios ◽  
R. Contieri
Keyword(s):  
Low Cost ◽  
Centrifugal Casting ◽  
Amorphous State ◽  
Bulk Sample ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
High Fracture ◽  
Crystalline Materials ◽  
Thermal Crystallization ◽  
Arc Melting

Bulk metallic glasses are attractive materials for structural and functional applications when compared to crystalline materials. The Cu-based glasses exhibit particular interest due primarily to their relatively low cost and high fracture resistance. In this work the Cu49.7Ti31.8Zr11.3Ni7.2 alloy was prepared from the mixture of pure metals by arc melting and following the ingot was re-melted by centrifugal casting in wedge-section copper mould. The structure of wedge bulk sample was evaluated by a combination of X-Ray Diffraction (XRD) and Differential Scanning Calorimetry (DSC). The results show that the amorphous state is formed in the thinner region and it is maintained up to thickness of 3.5 mm in the wedge bulk-sample. The crystallization temperature was observed above 400 °C coinciding with the studies of thermal crystallization by XRD and DSC. Dynamical heating of the amorphous phase from room temperature up to 750°C showed the formation of CuTi, Cu10Zr7 e Cu2TiZr crystalline phases.

scholarly journals Photocatalytic and adsorption properties of TiO2-pillared montmorillonite obtained by hydrothermally activated intercalation of titanium polyhydroxo complexes

2018 ◽  
Vol 9 ◽  
pp. 364-378 ◽  
Author(s):  
Mikhail F Butman ◽  
Nikolay L Ovchinnikov ◽  
Nikita S Karasev ◽  
Nataliya E Kochkina ◽  
Alexander V Agafonov ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Nitrogen Adsorption ◽  
Degree Of Crystallinity ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
New Approach ◽  
Pillared Montmorillonite ◽  
Degussa P25 ◽  
Adsorption Desorption ◽  
High Degree

We report on a new approach for the synthesis of TiO2-pillared montmorillonite, where the pillars exhibit a high degree of crystallinity (nanocrystals) representing a mixture of anatase and rutile phases. The structures exhibit improved adsorption and photocatalytic activity as a result of hydrothermally activated intercalation of titanium polyhydroxo complexes (i.e., TiCl4 hydrolysis products) in a solution with a concentration close to the sol formation limit. The materials, produced at various annealing temperatures from the intercalated samples, were characterized by infrared spectroscopy, differential scanning calorimetry (DSC)/thermogravimetric analysis (TGA), X-ray diffraction, dynamic light scattering (DLS) measurements, and liquefied nitrogen adsorption/desorption. The photocatalytic activity of the TiO2-pillared materials was studied using the degradation of anionic (methyl orange, MO) and cationic (rhodamine B, RhB) dyes in water under UV irradiation. The combined effect of adsorption and photocatalysis resulted in removal of 100% MO and 97.5% RhB (with an initial concentration of 40 mg/L and a photocatalyst-sorbent concentration of 1 g/L) in about 100 minutes. The produced TiO2-pillared montmorillonite showed increased photocatalytic activity as compared to the commercially available photocatalyst Degussa P25.

scholarly journals Granulation Of Porous Materials with Phase Change Material (PCM)

2021 ◽  
Vol 20 (3) ◽  
pp. 135-144
Author(s):  
Tomasz Bien
Keyword(s):  
Mechanical Strength ◽  
Phase Change ◽  
Construction Industry ◽  
Phase Change Materials ◽  
Nitrogen Adsorption ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Method Of Production ◽  
Adsorption Desorption ◽  
Change Material

The paper describes the research on the method of production of granulated phase-change materials (PCM) used in construction industry for the accumulation of thermal energy. As mineral materials for the granules preparation zeolite from fly ash Na-P1 and natural diatomite dust were used which were impregnated with paraffinic filtration waste and granulated using a combined granulation method. Obtained granules were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), nitrogen adsorption/desorption isotherm, and differential scanning calorimetry (DSC). Mechanical strength of the materials was determined in a “drop strength” test. Performed analyses revealed that mineral composition and micromorphology of the diatomite and zeolite granules were varied, with zeolite granules having higher mechanical strength.

Assessment on the Synthesis and Performance of Low-Cost Chitosan-Coated Natural Zeolite Adsorbent for Post-Combustion Carbon Dioxide Capture

2018 ◽  
Vol 775 ◽  
pp. 383-389
Author(s):  
Dominique Jan Bacalso Tan ◽  
Bryan B. Pajarito
Keyword(s):  
Carbon Dioxide ◽  
Natural Zeolite ◽  
Carbon Dioxide Capture ◽  
Low Cost ◽  
Gravimetric Analysis ◽  
Scanning Calorimetry ◽  
Zeolite Adsorbent ◽  
And Performance ◽  
Adsorption Desorption ◽  
Good Retention

An adsorbent for post-combustion carbon dioxide capture was prepared using low-cost and sustainable natural zeolite coated with chitosan. An optimum adsorbent was identified from 3 levels of particle size of natural zeolite and 10 levels of chitosan loading. The optimum adsorbent was characterized using infrared spectroscopy, scanning electron microscopy, thermal gravimetric analysis and differential scanning calorimetry. The chemical and thermal properties of the adsorbent indicated successful coating of chitosan on natural zeolite. The adsorbent registered competitive dynamic adsorption capacity of 0.81 mmol g-1 with good retention, at least, up to 5 adsorption-desorption cycles.

scholarly journals Synthesis and Characterization of Nanocrystalline Aluminophosphate AlPO4-5 Molecular Sieve

2018 ◽  
Vol 24 (3) ◽  
pp. 161
Author(s):  
Asir Alnaama
Keyword(s):  
Molecular Sieves ◽  
Ammonium Hydroxide ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Good Thermal Stability ◽  
Synthesis Parameters ◽  
Bet Analysis ◽  
Xrd Patterns ◽  
Adsorption Desorption

Nanocrystalline aluminophosphate AlPO4-5 molecular sieves were synthesized by hydrothermal method (HTS). Synthesis parameters like time and temperature of crystallization were investigated. Type of template (R) and ratio of R/P2O5 were studied also. Characterization of the synthesized AlPO4-5 were done by powder X-ray diffraction (XRD), scanning electron microscopy (SEM/EDX), Fourier transform infrared (FTIR), differential scanning calorimetry-thermogravimetry analysis (DSC-TGA), and N2 adsorption-desorption BET analysis. XRD patterns results showed excellent crystallinity for two types of templates, di-n-propylamine (DPA) and tetrapropyl ammonium hydroxide (TPAOH) for alumminophosphate five (AFI) structure. Nano-level for particle size of 66 nm was revealed by AFM test. Good thermal stability was obtained in DSC-TGA results. Best time and temperature of crystallization of 24h and 190 O C were got. Optimum R/P2O5 for two kind of template was established.  

Mechanochemical Synthesis of Nanocrystalline CeO2: The Effect of Annealing Temperatures on the Particle Size

2006 ◽  
Vol 517 ◽  
pp. 252-256 ◽  
Author(s):  
Abdul Hadi ◽  
Iskandar Idris Yaacob ◽  
Lee Seok Ling
Keyword(s):  
Annealing Temperature ◽  
Gas Adsorption ◽  
Weight Ratio ◽  
X Ray Diffraction ◽  
Treatment Results ◽  
Scanning Calorimetry ◽  
Characterization Methods ◽  
X Ray ◽  
Annealing Temperatures ◽  
Adsorption Desorption

Cerium dioxide (CeO2) nanoparticles were synthesized by a novel mechanochemical process. The precursors of Ce2(CO3)3.xH2O and NaOH were mixed at a weight ratio of 4 to 1. The mixtures were milled using a planetary ball mill with ball to powder ratio of 10:1. The products were then characterized using a battery of characterization methods, including X-ray diffraction (XRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and gas adsorption-desorption measurement. The as-prepared particles were largely amorphous with an average specific surface area of about 119.94 m2/g. Nanocrystalline CeO2 with crystallite size of 4.5 nm was obtained when the sample was annealed in air at 350 oC. The heat treatment results showed that the crystallinity of nanocrystalline CeO2 increased with increasing annealing temperature.

scholarly journals Selective adsorption of PHC and regeneration of washing effluents by modified diatomite

2020 ◽  
Vol 81 (10) ◽  
pp. 2066-2077
Author(s):  
Zhuoqi Xu ◽  
Gengbo Ren ◽  
Yanying Zhu ◽  
Xiaodong Ma ◽  
Hongrui Li ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Selective Adsorption ◽  
Low Cost ◽  
Soil Washing ◽  
X Ray Diffraction ◽  
X Ray ◽  
Monolayer Adsorption ◽  
Pseudo Second Order ◽  
Adsorption Desorption ◽  
Modified Diatomite

Abstract Selective removal of petroleum hydrocarbons (PHCs) from soil washing effluents is the key to the surfactant-enhanced soil washing technology. In this study, the diatomite was modified by nonionic surfactant TX-100 and applied in the selective adsorption of PHCs in the soil washing effluents. The modified diatomites were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, N2 adsorption/desorption and X-ray photoelectron spectroscopy respectively. The adsorption process followed the pseudo-second-order model and the adsorption isotherms indicated that the interaction between PHCs and modified diatomite was monolayer adsorption. The important operating factors such as TX-100 dosage, adsorbent dosage, time and temperature were optimized. With the participation of the low-cost adsorbent TX3-Db with high adsorption capacity, the recovery efficiency of the washing effluents was still up to 78.9% after three cycles. A selective adsorption mechanism, based on steric hindrance and electrostatic repulsion, was proposed to explain the removal of PHCs from washing effluents.

scholarly journals Influence of Multiple Factors on the Explosion Characteristics of Flammable Gases in Municipal Sewage Pipelines

2020 ◽  
Vol 2020 ◽  
pp. 1-17
Author(s):  
Pengfei Lv ◽  
Jiaxu Zhang ◽  
Lei Pang ◽  
Kai Yang ◽  
Siheng Sun
Keyword(s):  
Flame Propagation ◽  
Propagation Velocity ◽  
Horizontal Well ◽  
Substantial Effect ◽  
Municipal Sewage ◽  
Flame Propagation Velocity ◽  
Explosion Pressure ◽  
Significant Difference ◽  
Pressure Peak ◽  
Oil Gas

Using the hydrodynamic software Fluidyn, a numerical model comprising a top-sealed vertical inspection well and a horizontal well with openings at both ends was built based on symmetry, to study the explosion propagation of flammable gases in typical municipal sewage pipelines. The vertical well had a diameter of 0.7 m and different depths (2 m, 4 m, and 6 m), and the horizontal well had a diameter of 0.8 m and a length of 20 m at both sides. The effects of different ignition positions, well depths, and gas compositions and concentrations on the explosion characteristics and rules governing the propagation of flammable gases in a municipal sewage pipeline were investigated. The findings suggest that different ignition positions (at the top, middle, and bottom of the inspection well) did not lead to a significant difference between peak explosion pressure and temperatures but had a substantial influence on the propagation velocity of the explosion flame near the corner of the junction between the vertical inspection well and the horizontal well. Different inspection well depths had no significant impact on the peak explosion pressure or temperature but had a substantial effect on the propagation velocity of the explosion flame at the bottom of the well. Compared with a methane (CH4) explosion at a concentration of 6%, the peak explosion pressure, peak explosion temperature, and flame propagation velocity of a CH4 and oil-gas mixture at a concentration ratio of 6% : 1% were found to be significantly higher. With increasing oil-gas concentrations (2%, 4%, and 6%), the peak pressure, temperature, and flame propagation velocity continued to decrease. The findings of this study can help prevent explosion accidents in municipal sewage pipelines and provide a reference to support the establishment of related standards.

scholarly journals Synthesis of Medium-temperature Protonic Conductor CsHSO4-Al2O3

2013 ◽  
Vol 16 (4) ◽  
pp. 273-278
Author(s):  
L.B. Yang ◽  
W.S. Ning ◽  
X.D. Wang ◽  
W. Liu ◽  
H.Y. Shen ◽  
...  
Keyword(s):  
Nitrogen Adsorption ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Medium Temperature ◽  
X Ray ◽  
Rotating Speed ◽  
Structures And Properties ◽  
Protonic Conductors ◽  
Desorption Isotherms ◽  
Adsorption Desorption

In this study, different methods are used to synthesize novel medium-temperature protonic conductors from CsHSO4 and mesoporous Al2O3. X-ray diffraction, scanning electron microscopy, thermogravimetric analysis and differential scanning calorimetry, and nitrogen adsorption-desorption isotherms are performed to investigate the structures and properties of CsHSO4-Al2O3 conductors. Results show that the proton conductivities of the prepared CsHSO4-Al2O3 conductors increase as temperature increases from 100 °C to 200 °C. The optimum method involves mixing the equimolar CsHSO4 and Al2O3 with 5 ml ethanol and subsequently ball milling at a rotating speed of 200 rpm for 2 h. The highest proton conductivity obtained in this study is 1.06×10-6 S·cm–1 at 200 °C.

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