The Experts below are selected from a list of 64842 Experts worldwide ranked by ideXlab platform
S T Kolaczkoski - One of the best experts on this subject based on the ideXlab platform.
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catalytic stationary gas turbine combustors a review of the challenges faced to clear the next set of hurdles chemical reaction engineering
Chemical Engineering Research & Design, 1995Co-Authors: S T KolaczkoskiAbstract:In response to the need to develop low NO x combustors, there has been renewed interest in catalytic combustion and a new sense of urgency in seeking to overcome the remaining hurdles and develop a commercial unit. Starting with an explanation of how the shape of a «light-off» curve for a Catalyst may vary, progress in the development of low, medium and High Temperature Catalyst systems is described. Since gas turbines need to be capable of operating at varying power loads, where the gas inlet conditions vary, hybrid systems have been developed. These are reviewed in this paper and the challenges faced by interdisciplinary teams working on system designs are described. In general, schemes have progressed on the lines of maximizing catalytic reactions until gas Temperatures exceed 800°C, at which point homogeneous reactions become significant. Since natural gas is an abundant and relatively clean fuel, it is used in many of the schemes described, and because of pressure drop constraints monoliths are favoured as Catalyst support systems. Practical advice is also provided on the use of mathematical modelling techniques which should proceed in parallel with system design, utilizing established knowledge in chemical reaction engineering in order to make progress. An overview of the reactions and transport processes taking place is described, and the difficulties of obtaining kinetic and transport/ physical property data are outlined. Despite the considerable progress that has been made, many challenges remain and a number of these centre on system design and how to cope with varying power loads. In addition, issues concerning Catalyst durability, fuel-air mixing, minimization of stresses, and start-up need attention
Vincent Jourdain - One of the best experts on this subject based on the ideXlab platform.
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processes controlling the diameter distribution of single walled carbon nanotubes during catalytic chemical vapor deposition
ACS Nano, 2011Co-Authors: Matthieu Picher, Eric Anglaret, Raul Arenal, Vincent JourdainAbstract:Single-walled carbon nanotubes are grown by catalytic chemical vapor deposition in various conditions of Temperature and carbon precursor pressure. Systematic analyses of the Raman radial breathing modes at two laser wavelengths are used to monitor the evolution of the diameter distribution. Two distinct domains with opposite influences of the Temperature and the precursor pressure on the diameter distribution are evidenced. Thanks to specially designed experiments made of two successive growths, three processes are identified to influence the diameter distribution during the nanotube growth: (i) at too low precursor pressure, nanotube nucleation cannot occur on the smallest Catalyst particles; (ii) at low Temperature and High precursor pressure, small Catalyst particles are preferably encapsulated by disordered carbon structures; (iii) at High Temperature, Catalyst coarsening causes the disappearance of the smallest Catalyst particles.
Jian Guo Jheng - One of the best experts on this subject based on the ideXlab platform.
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characterization of water gas shift reaction in association with carbon dioxide sequestration
Journal of Power Sources, 2007Co-Authors: Wei Hsin Chen, Jian Guo JhengAbstract:The characteristics of a water gas shift reaction (WGSR) in association with carbon dioxide sequestration under the effects of a High-Temperature Catalyst (HTC) and a low-Temperature Catalyst (LTC) are studied experimentally. With the condition of fixed residence time (0.1 s) for the reactants in the Catalyst bed, it is found that the reaction behaviors with the HTC are inherently different from those with the LTC. Specifically, for the WGSR with the HTC, the reaction can be divided into a rapid growth regime, a progressive growth regime and a slow growth regime with increasing reaction Temperature or steam/CO ratio. With regard to the WGSR with the LTC, three different regimes are also exhibited; however, they consist of a rapid growth regime, a progressive decay regime and a growth-frozen regime. According to the aforementioned characteristics, proper or better operation conditions using the HTC and the LTC for the application of fuel cells are suggested. When the product gas passes through a Ca(OH)2 solution, the obtained results reveal that CO2 removal efficiency increases with increasing solution concentration or steam/CO ratio for both the HTC and the LTC used in the WGSR. © 2007 Elsevier B.V. All rights reserved.
Feng Hou - One of the best experts on this subject based on the ideXlab platform.
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microstructure and properties of inter locked mullite framework prepared by the tba based gel casting process
Ceramics International, 2016Co-Authors: Shan Liu, Jiachen Liu, Feng HouAbstract:Abstract Inter-locked mullite frameworks (IM frameworks) were prepared by the tert butyl alcohol (TBA) -based gel-casting method. The inter-locked structure formed through fluorine-catalyzed gas-phase reaction. Inter-locked topaz structure first formed in the samples and then it transformed into inter-locked mullite structure. TBA's volatilization and gaseous reactants' running off, which acted as two kinds of “pore formers” in the gel-casting process, offered enough space for the mullite grains' anisotropic growth, and led to the porous structure's formation. The volume density, apparent porosity, specific surface area and compression strength of the samples that formed at 1100–1500 °C were found to be 0.53–0.59 g/cm 3 , 82.1–76.1%, 12.3–4.6 m 2 /g and 1.6–3.6 MPa, respectively, indicating that the IM frameworks are promising as High-Temperature Catalyst supports.
Matthieu Picher - One of the best experts on this subject based on the ideXlab platform.
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processes controlling the diameter distribution of single walled carbon nanotubes during catalytic chemical vapor deposition
ACS Nano, 2011Co-Authors: Matthieu Picher, Eric Anglaret, Raul Arenal, Vincent JourdainAbstract:Single-walled carbon nanotubes are grown by catalytic chemical vapor deposition in various conditions of Temperature and carbon precursor pressure. Systematic analyses of the Raman radial breathing modes at two laser wavelengths are used to monitor the evolution of the diameter distribution. Two distinct domains with opposite influences of the Temperature and the precursor pressure on the diameter distribution are evidenced. Thanks to specially designed experiments made of two successive growths, three processes are identified to influence the diameter distribution during the nanotube growth: (i) at too low precursor pressure, nanotube nucleation cannot occur on the smallest Catalyst particles; (ii) at low Temperature and High precursor pressure, small Catalyst particles are preferably encapsulated by disordered carbon structures; (iii) at High Temperature, Catalyst coarsening causes the disappearance of the smallest Catalyst particles.