scholarly journals Investigation of carbon deposition induced by pyrolytic decomposition of ethylene

RSC Advances ◽  
2017 ◽  
Vol 7 (47) ◽  
pp. 29639-29644 ◽  
Author(s):  
Ling Lin ◽  
Meishuang Lai ◽  
Haifang Li ◽  
Fei Tian ◽  
Yulong Chen ◽  
...  

We employed Raman spectroscopy to characterize the formed carbon deposits under different conditions inside a built-in U-shape quartz tube for unravelling mechanism of carbon deposition on stainless steel.

2021 ◽  
Author(s):  
YiRan Zhang ◽  
Jianfen Li ◽  
Bolin Li ◽  
Zeshan Li ◽  
Yun He ◽  
...  

Abstract The developed Ni-La/Al2O3-CeO2-Bamboo charcoal (ACB) catalyst was applied to the co-pyrolysis of straw and plastic to produce hydrogen in a horizontal quartz tube pyrolysis furnace. In this study, the effects of the mixing ratio of straw and plastic, the presence and stability of the catalyst on the co-pyrolysis hydrogen production were investigated. Experiment showed that the addition of PE can increase the yield of H2 within a certain range, and the best mass ratio of 5:5 was found. In the co-pyrolysis process with the participation of the catalysts, the macromolecular tar can be cracked into combustible gases such as H2, and the H2 yield could be increased to 332.2ml/g (Ni-La/ACB) is much higher than 68.87ml/g without catalyst. Compared with Ni/ACB, Ni-La/ACB had been increased the alkalinity by adding La element and enhanced the carbon deposition resistance of the catalyst, which makes the catalyst maintain higher stability. This was also confirmed in stability test experiments.


1971 ◽  
Vol 25 (1) ◽  
pp. 80-82 ◽  
Author(s):  
Arvin S. Quist

A captive liquid, or windowless cell has been developed for laser–Raman spectroscopy of molten fluorides. This all-metal cell, [Formula: see text] in. o.d. and [Formula: see text] in. long, is contained in a 6 mm i.d., 8 mm o.d. quartz tube which has an optical flat fused to one end. There is no direct contact between the fused salt and the quartz container. Cells of this design, constructed either from nickel or copper, have been used for Raman studies of molten fluorides to 800°C.


2006 ◽  
Vol 524-525 ◽  
pp. 957-962 ◽  
Author(s):  
Gabrielle Hilson ◽  
Keith R. Hallam ◽  
Peter E.J. Flewitt

Raman spectroscopy has been used by various workers to provide a measure of the stresses within the oxides grown on metal substrates at high temperatures. In this paper, we consider thermally grown oxides produced on a Type 316 austenitic stainless steel and an iron 3% silicon ferritic steel. The oxides were grown in air at temperatures of 950oC and 650oC respectively over a range of times. These oxides have been characterised by producing cross-sections using focused ion beam milling. The variation of the Raman spectra wave number (He, Ne laser; λ = 633nm) for the oxides produced on the polycrystalline austenitic stainless steel and the ferritic steel were measured as a function of oxide thickness. This shift in wave number was a function of stress. For a fixed oxide thickness on the stainless steel substrate the specimen has been subject to a bending force. A back face strain gauge fixed to the metal substrate provided a measure of the applied strain. The peak wave number varied with applied strain. The results are discussed with respect to the potential to characterise the stresses produced in thermally grown oxides and as a tool to monitor applied stress.


2021 ◽  
Author(s):  
Rubens W.S. Lima ◽  
Thiago L.R. Hewer ◽  
Rita M.B. Alves ◽  
Martin Schmal

Abstract We studied and identified compounds adsorbed or deposited on the catalysts surface of the Ni-Mo supported on alumina and SBA-15, before and after hydrodeoxigenation of a bio-oil model (guaiacol). Marked differences were observed on both catalysts through DRIFTS and Raman spectroscopy showing that the alumina-supported catalyst contains deposits of aromatic and oxygenated organic substances, while the carbon deposits on the SBA-15 as aliphatic simple molecules. TPO analyses confirm that the carbon deposited on the NiMo/SBA-15 catalyst were light polymer types, mainly nanotubes and nano fibers, while on the alumina catalyst the mainly carbon species formed were graphite type and heavier carbons. Post reaction analysis of the catalysts showed coke formation and carbon deposition rate of 1.14 mgcoke.gcat−1 h− 1 for NiMo/SBA-15 and the deactivation was 44 % higher for the NiMo/Al2O3 with 1.65 mgcoke.gcat−1 h− 1of carbon deposition rate.


Metals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1347
Author(s):  
Hany S. Abdo ◽  
Asiful H. Seikh

The electrochemical behavior of 304 austenitic stainless steel (304ASS) was studied by different methods such as potentiodynamic polarization, EIS, SEM, and Raman spectroscopy. Potentiodynamic polarization data suggest that 304 ASS could be more susceptible to corrosion due to the presence of H2S. The coexistence of H2S and Cl−-type ionic species in 304 ASS lead to a decrease in the corrosion resistance as compared to the H2S-free condition. It is seen that CO2 helps form a passive layer on the metallic surface, which eventually decreases its corrosion rate. Raman spectroscopy analysis shows that the passive layer developed under different condition consists of FeCO3, FeS2, Fe2O3, Fe(OH)2, etc. SEM images further confirm that elemental S− and Cl− can infiltrate the passive film and cause the passive film to deteriorate.


2010 ◽  
Vol 160-162 ◽  
pp. 1394-1398
Author(s):  
Jin Song Lei ◽  
Zhao Qiang Zhang ◽  
Yong Yao

In this paper, we report the deposition of nano-crystalline silicon flexible solar cells on stainless steel (SS) substrates for application in solar roof. The influence of substrate treatment on the properties of material and the solar cells was studied by Raman spectroscopy, scanning electron microscope, current-voltage (I-V), and Quantum efficiency (QE) measurements. Results suggest that the properties of the Si:H thin films and solar cells were greatly improved by the substrate treatment with surface polishing and the followed Ag/ZnO electrodes deposition.


Author(s):  
Valérie Eveloy

Anode fuel and steam recycling are explored as possible mitigation strategies against carbon deposition in an internal methane reforming solid oxide fuel cell (IR-SOFC) operated at steam-to-carbon ratios (S:Cs) of 0.5–1. Using a detailed computational fluid dynamics model, the cell behavior and spatial extent of carbon deposits within the anode are analyzed based on a thermodynamic analysis accounting for both the cracking and Boudouard reactions for fuel and steam recycling fractions of up to 90% (mass percent). At temperatures close to 1173 K, 50% fuel recycling is found to be an effective mitigation strategy against carbon deposition, with only a minor portion of the cell inlet affected by coking. Steam recycling reduces the extent of carbon deposits by a magnitude comparable to that obtained using fuel recycling, provided that recycling ratios on the order of 25% higher than that for fuel recycling are applied. Steam recycling could therefore be considered advantageous in terms of reduced overall mass flow. The mitigating effect of fuel recycling on the susceptibility to coking at the cell inlet is found to be through the direction of the cracking reaction, while steam recycling has a positive (but slightly less effective) impact on both the Boudouard and cracking reactions. The results suggest that partial anode gas recycling could help extend the operational range of IR-SOFCs to lower fuel humidification levels than typically considered, with reduced thermal stresses and risks of carbon deposits, while reducing system cost and complexity in terms of steam production.


2016 ◽  
Vol 48 (1) ◽  
pp. 119-125 ◽  
Author(s):  
Aaran T. Lewis ◽  
Riana Gaifulina ◽  
Martin Isabelle ◽  
Jennifer Dorney ◽  
Mae L. Woods ◽  
...  

2014 ◽  
Vol 996 ◽  
pp. 906-911 ◽  
Author(s):  
Souhail Benafia ◽  
Delphine Retraint ◽  
Benoit Panicaud ◽  
Jean Luc Grosseau-Poussard

In this paper, the effects of Surface Mechanical Attrition Treatment on the high-temperature oxidation of AISI 316L austenitic stainless steel are investigated. Samples treated with different conditions were oxidized at 650°C in order to study the effect of this type of nanocrystallisation on the oxidation resistance of the alloy concerned. X-ray diffraction and in-situ Raman spectroscopy were used to identify the oxides formed at the surface. The results indicate the presence of hematite and chromium oxides. Experimental results obtained by Raman spectroscopy were also used to study the stress evolution in Cr2O3films during isothermal conditions.


1997 ◽  
Vol 496 ◽  
Author(s):  
D. S. Ginley ◽  
J. D. Perkins ◽  
J. M. McGraw ◽  
P. A. Parilla ◽  
M.L. Fu ◽  
...  

AbstractWe report on the use of pulsed laser depositon (PLD) to grow thin films of LiCoO2 on a number of low cost substrates including SnO2 coated Upilex, stainless steel and SnO2 coated glass. Highly textured (001) films grown on CVD deposited SnO2 films on 7059 glass, were obtained at 200 to 500 mTorr O2 and a temperature of 500 C. Similar texture was not obtained on the stainless or Upilex however dense films from crystalline to amorphous were obtained. The films were characterized by x-ray diffraction and Raman spectroscopy.


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