scholarly journals Natural Clays of the Kazakhstan Deposits for Catalysts of Cracking

2017 ◽  
Vol 4 (2) ◽  
pp. 141
Author(s):  
N.A. Zakarina ◽  
L.D. Volkova ◽  
O.V. Chshukina
Keyword(s):  
Zeolite Y ◽  
Optical Emission ◽  
Acid Activation ◽  
Composite Catalysts ◽  
Oil Fraction ◽  
Before And After ◽  
Fixed Catalyst ◽  
Natural Clays ◽  
Thermal Stability Of ◽  
Cracking Catalysts

Presented paper is devoted to the construction of cracking catalysts based on H-form zeolite Y, modifying by heteropolyacids of 12 row decationzed forms of natural clays of Tagan and Narynkol deposits. Conditions of acid activation were compared for Tagan clay. Chemical composition of clays before and after activation was detected by optical emission spectral method; phase composition was detected with X-ray<br />diffraction. It has been shown that activities of composite catalysts are related to the concentration and sequence of HPA adding. From the results the conclusion was drawn that amount of adding HPA influenced the activity and thermal stability of catalysts prepared on the base of Tagan and Narynkol clays deposits. The synthesized catalysts were studied in a laboratory microimpulse catalytic set by the model reaction of isopropylbenzene cracking at temperature 350-500 °C. The optimum compositions of zeolite containing contacts served as the base of creation of cracking catalysts for real raw (kerosene-gas-oil fraction) into quartz reactor with a fixed catalyst bed. These prepared catalysts have demonstrated enhanced thermal<br />stability and high activity. Stronger cracking activity of catalysts prepared on the base of Narynkol clay has been shown.

Surface roughness measurements of vanadium-contaminated fluidized cracking catalysts by atomic force microscopy

1996 ◽  
Vol 54 ◽  
pp. 866-867
Author(s):  
H. Kinney ◽  
M.L. Occelli ◽  
S.A.C. Gould
Keyword(s):  
Surface Roughness ◽  
Zeolite Y ◽  
Atomic Level ◽  
Microporous Structure ◽  
Contact Mode ◽  
Force Microscopy ◽  
Atomic Force ◽  
Before And After ◽  
Roughness Measurements ◽  
Cracking Catalysts

For this study we have used a contact mode atomic force microscope (AFM) to study to topography of fluidized cracking catalysts (FCC), before and after contamination with 5% vanadium. We selected the AFM because of its ability to well characterize the surface roughness of materials down to the atomic level. It is believed that the cracking in the FCCs occurs mainly on the catalysts top 10-15 μm suggesting that the surface corrugation could play a key role in the FCCs microactivity properties. To test this hypothesis, we chose vanadium as a contaminate because this metal is capable of irreversibly destroying the FCC crystallinity as well as it microporous structure. In addition, we wanted to examine the extent to which steaming affects the vanadium contaminated FCC. Using the AFM, we measured the surface roughness of FCCs, before and after contamination and after steaming.We obtained our FCC (GRZ-1) from Davison. The FCC is generated so that it contains and estimated 35% rare earth exchaged zeolite Y, 50% kaolin and 15% binder.

scholarly journals Effect of wood biomass components on self-heating

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Nozomi Miyawaki ◽  
Takashi Fukushima ◽  
Takafumi Mizuno ◽  
Miyao Inoue ◽  
Kenji Takisawa
Keyword(s):  
Moisture Content ◽  
Inductively Coupled Plasma ◽  
Optical Emission ◽  
Chemical Oxidation ◽  
Spontaneous Ignition ◽  
Emission Spectrometry ◽  
Inductively Coupled ◽  
Self Heating ◽  
Inorganic Substances ◽  
Before And After

AbstractBiomass may ignite due to biological oxidation and chemical oxidation. If this phenomenon (spontaneous ignition) is controlled, it would be possible to produce biochar at a lower cost without the need for an external heat resource. We investigated if self-heating could be controlled by using sawdust and bark chips. When sawdust and bark chips were used under controlled conditions, the bark chips temperature increased to the torrefaction temperature. The ash content of bark chips was ~ 2%d.b. higher than that of sawdust; consequently, the inorganic substances contained in the bark chips might affect the self-heating. Self-heating was suppressed when inorganic substances were removed by washing with water. Therefore, the inorganic substances in the biomass might have affected self-heating. The inorganic element contents of the bark chips were measured by inductively coupled plasma optical emission spectrometry before and after washing. The potassium content of the bark chips was reduced remarkably by washing, and there was a possible influence of potassium on self-heating. Finally, the effect of moisture content on self-heating was investigated to obtain stable reactivity. Thus, at a moisture content of 40%w.b., a steady self-heating behavior may be realized.

scholarly journals Static and Dynamic Behavior of Polymer/Graphite Oxide Nanocomposites before and after Thermal Reduction

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1008
Author(s):  
Kiriaki Chrissopoulou ◽  
Krystalenia Androulaki ◽  
Massimiliano Labardi ◽  
Spiros H. Anastasiadis
Keyword(s):  
Graphite Oxide ◽  
Thermal Reduction ◽  
Polymer Chains ◽  
Solid Surfaces ◽  
Relaxation Processes ◽  
Thermal Transitions ◽  
Reduced Graphite Oxide ◽  
Before And After ◽  
Similarities And Differences ◽  
Thermal Stability Of

Nanocomposites of hyperbranched polymers with graphitic materials are investigated with respect to their structure and thermal properties as well as the dynamics of the polymer probing the effect of the different intercalated or exfoliated structure. Three generations of hyperbranched polyester polyols are mixed with graphite oxide (GO) and the favorable interactions between the polymers and the solid surfaces lead to intercalated structure. The thermal transitions of the confined chains are suppressed, whereas their dynamics show similarities and differences with the dynamics of the neat polymers. The three relaxation processes observed for the neat polymers are observed in the nanohybrids as well, but with different temperature dependencies. Thermal reduction of the graphite oxide in the presence of the polymer to produce reduced graphite oxide (rGO) reveals an increase in the reduction temperature, which is accompanied by decreased thermal stability of the polymer. The de-oxygenation of the graphite oxide leads to the destruction of the intercalated structure and to the dispersion of the rGO layers within the polymeric matrix because of the modification of the interactions between the polymer chains and the surfaces. A significant increase in the conductivity of the resulting nanocomposites, in comparison to both the polymers and the intercalated nanohybrids, indicates the formation of a percolated rGO network.

scholarly journals Investigation of activated Al-pillared clay efficiency in vegetable oil purification

2004 ◽  
pp. 31-36 ◽  
Author(s):  
Gizela Lomic ◽  
Erne Kis ◽  
Etelka Dimic ◽  
Ranko Romanic
Keyword(s):  
Surface Area ◽  
Vegetable Oil ◽  
Total Pore Volume ◽  
Textural Properties ◽  
Sample Surface ◽  
Pillared Clay ◽  
Acid Activation ◽  
Micropore Surface Area ◽  
Natural Clays ◽  
Oil Purification

This paper represents a contribution to the applicability of natural clays and their derivates as adsorbents in the process of purification of vegetable oil. Investigation of textural properties of raw and purified clay samples reveals that during acid activation and Al-pillaring, BET and micropore surface area increases significantly. However, bleaching capacity of clay and its derivates is not determined by using sample surface area, but rather sample total pore volume. Surface area, especially micropore surface area contributes to removal of smaller molecules. This was confirmed by successful elimination of moisture and volatile materials by samples with an appropriate micropore structure. Used samples of clay and its derivates do not significantly influence acid and peroxide values of raw sunflower oil during its treatment.

scholarly journals Polystyrene/Montmorillonite Nanocomposites: Study of the Morphology and Effects of Sonication Time on Thermal Stability

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Mashael Alshabanat ◽  
Amal Al-Arrash ◽  
Waffa Mekhamer
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
Solution Method ◽  
Sonication Time ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Polystyrene Matrix ◽  
Before And After ◽  
Silicate Layers ◽  
Thermal Stability Of

Polymer nanocomposites of polystyrene matrix containing 10% wt of organo-montmorillonite (organo-MMT) were prepared using the solution method with sonication times of 0.5, 1, 1.5, and 2 hours. Cetyltrimethylammonium bromide (CTAB) is used to modify the montmorillonite clay after saturating its surface with Na+ions. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were used to characterize the montmorillonite before and after modification by CTAB. The prepared nanocomposites were characterized using the same analysis methods. These results confirm the intercalation of PS in the interlamellar spaces of organo-MMT with a very small quantity of exfoliation of the silicate layers within the PS matrix of all samples at all studied times of sonication. The thermal stability of the nanocomposites was measured using thermogravimetric analysis (TGA). The results show clear improvement, and the effects of sonication time are noted.

scholarly journals Graphene Nanoplatelets-Based Ni-Zeolite Composite Catalysts for Heptane Hydrocracking

2020 ◽  
Vol 6 (2) ◽  
pp. 31
Author(s):  
Roba Saab ◽  
Kyriaki Polychronopoulou ◽  
Nikolaos Charisiou ◽  
Maria A. Goula ◽  
Andreas Schiffer
Keyword(s):  
Water Adsorption ◽  
Catalyst Surface ◽  
Zeolite Y ◽  
Graphene Nanoplatelets ◽  
Bet Surface Area ◽  
Composite Catalysts ◽  
Texture Characteristics ◽  
Hydrophobic Nature ◽  
Two Temperatures ◽  
Zeolite Composite

This paper examines the effect of incorporating graphene nanoplatelets (GNPs) in an Ni-based/Zeolite-Y catalyst on the hydrocracking of heptane fuel at two temperatures, 350 and 400 °C. Specifically, reduced GNP/NiO-ZY and NiO-ZY catalysts, each with a 5 wt. % Ni loading, were compared in this study. The results show that the reduced GNP/NiO-ZY enhanced the conversion percentage by 31% at 350 °C and by 6% at 400 °C as compared with the reduced NiO-ZY, and the GNP/NiO-ZY also showed superior stability, reporting a less than 2% drop in conversion over 20 h of time-on-stream. The enhancement in performance is linked to the surface and texture characteristics of both catalysts. Although the calcined GNP/NiO-ZY possessed a lower Brunauer–Emmett–Teller (BET) surface area of 458 m2/g compared with 536 m2/g for the calcined NiO-ZY, it showed a more hydrophobic nature, as deduced from the water adsorption profiles, which corroborates the hypothesis that the increased affinity between the catalyst surface and heptane molecules during the reaction leads to an improved catalytic activity.

scholarly journals Effect of Acid Activation-Hydrophilic-Modified Sepiolite on Comprehensive Properties of Oil-Well Cement

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Yihang Zhang ◽  
Miao He ◽  
Mingbiao Xu ◽  
Peng Xu
Keyword(s):  
Cement Paste ◽  
Oil Well ◽  
Acid Activation ◽  
Cement Slurry ◽  
Comprehensive Properties ◽  
Oil Well Cement ◽  
Before And After ◽  
Sepiolite Fiber ◽  
Well Cement ◽  
Agent Treatment

In this paper, sepiolite was treated by acid activation, coupling agent treatment, and sulfonation modification. The purpose of this study was to explore the changes in the fluidity and mechanical properties of sepiolite cement slurry before and after modification. Therefore, the comprehensive properties of unmodified sepiolite fiber (HPS) and acid activation-coupling agent treatment-sulfonated sepiolite fiber (S-O-H-HPS) in oil-well cement slurry were evaluated. FT-IR and microscopic mechanism of cement paste fracture surface before and after sepiolite modification were analyzed. The results showed that HPS can effectively improve the toughness of cement paste, but when the content of HPS was more than 1%, the fluidity of cement paste deteriorated sharply and the compressive strength decreased gradually. The addition of S-O-H-HPS can significantly improve the fluidity and stability of HPS slurry. Without affecting the compressive strength, it can effectively improve the flexural strength and impact strength and reduce the elastic modulus of cement paste. The mechanism analysis showed that S-O-H-HPS can not only form network structure in cement paste but also improve the toughness of cement paste by forming a bridge. This also explains why the strength of S-O-H-HPS cement paste does not decrease significantly with the increase of S-O-H-HPS.

scholarly journals Evolving optical polarisation of the black hole X-ray binary MAXI J1820+070

2019 ◽  
Vol 623 ◽  
pp. A75 ◽  
Author(s):  
Alexandra Veledina ◽  
Andrei V. Berdyugin ◽  
Ilia A. Kosenkov ◽  
Jari J. E. Kajava ◽  
Sergey S. Tsygankov ◽  
...  
Keyword(s):  
Black Hole ◽  
Optical Emission ◽  
Position Angle ◽  
Stokes Parameters ◽  
X Ray ◽  
Before And After ◽  
Stokes Vectors ◽  
The Magnetic Field ◽  
Optical Polarisation ◽  
Polarisation Measurements

Aims. The optical emission of black hole transients increases by several magnitudes during the X-ray outbursts. Whether the extra light arises from the X-ray heated outer disc, from the inner hot accretion flow, or from the jet is currently debated. Optical polarisation measurements are able to distinguish the relative contributions of these components. Methods. We present the results of BVR polarisation measurements of the black hole X-ray binary MAXI J1820+070 during the period of March-April 2018. Results. We detect small, ∼0.7%, but statistically significant polarisation, part of which is of interstellar origin. Depending on the interstellar polarisation estimate, the intrinsic polarisation degree of the source is between ∼0.3% and 0.7%, and the polarisation position angle is between ∼10 ° −30°. We show that the polarisation increases after MJD 58222 (2018 April 14). The change is of the order of 0.1% and is most pronounced in the R band. The change of the source Stokes parameters occurs simultaneously with the drop of the observed V-band flux and a slow softening of the X-ray spectrum. The Stokes vectors of intrinsic polarisation before and after the drop are parallel, at least in the V and R filters. Conclusions. We suggest that the increased polarisation is due to the decreasing contribution of the non-polarized component, which we associate with the the hot flow or jet emission. The low polarisation can result from the tangled geometry of the magnetic field or from the Faraday rotation in the dense, ionised, and magnetised medium close to the black hole. The polarized optical emission is likely produced by the irradiated disc or by scattering of its radiation in the optically thin outflow.

A Description of the Kinetics and Mechanisms which Control the Release of Hlw Elements from Synroc

1990 ◽  
Vol 212 ◽  
Author(s):  
K. L. Smith ◽  
K. P. Hart ◽  
G. R. Lumpkin ◽  
P. McGlinn ◽  
P. Lam ◽  
...  
Keyword(s):  
Emission Spectroscopy ◽  
Optical Emission Spectroscopy ◽  
Optical Emission ◽  
Effect Of Temperature ◽  
Secondary Phases ◽  
Surface Layers ◽  
Before And After ◽  
Bicarbonate Solutions ◽  
Icp Mass Spectrometry ◽  
Kinetics Of

ABSTRACTLeaching tests were carried out on well-characterised Synroc C specimens containing 10 wt% simulated HLW. The effect of temperature and leachant composition on the mechanisms and kinetics of leaching were investigated by leaching Synroc specimens in deionised water at 70°C and 150°C, and in silicate and bicarbonate solutions at 70°C. SEM and TEM were used before and after leaching to characterise the primary and secondary phases in and on the Synroc samples, and to describe the morphological and chemical changes which occurred. Leachants were analysed using ICP/optical emission spectroscopy and ICP/mass spectrometry.Titaniferous surface layers were observed on the surface after exposure to leachants. Analysis of the leaching data has established that these surface layers can reduce the release of HLW elements from Synroc and that variations in temperature and leachant composition can hinder or promote the formation of secondary phases.

Thermal Stability of Thermal Interface Pastes, Evaluated by Thermal Contact Conductance Measurement

2000 ◽  
Vol 123 (3) ◽  
pp. 309-311 ◽  
Author(s):  
Xiangcheng Luo, ◽  
Yunsheng Xu, and ◽  
D. D. L. Chung
Keyword(s):  
Sodium Silicate ◽  
Thermal Contact ◽  
The Other ◽  
Thermal Contact Conductance ◽  
Conductance Measurement ◽  
Thermal Interface ◽  
Contact Conductance ◽  
Before And After ◽  
Heating Up ◽  
Thermal Stability Of

Thermal interface pastes based on silicone, lithium doped polyethylene glycol (PEG), and sodium silicate were evaluated in their performance before and after heating up to 120°C. The thermal contact conductance of any of the pastes between copper disks decreased after heating, such that the fractional decrease was less for the silicone-based paste than the PEG-based and sodium-silicate-based pastes. Nevertheless, the conductance was lower for the silicone-based paste than the other pastes both before and after heating up to 100 cycles.

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