Electrolytic Generation of Nano-Scale Carbon Phases with Framework Structures in Molten Salts on Metal Cathodes

2008 ◽  
Vol 63 (7-8) ◽  
pp. 467-474 ◽  
Author(s):  
Inessa A. Novoselova ◽  
Nikolai F. Oliinyk ◽  
Anastasiya B. Voronina ◽  
Sergei V. Volkov
Keyword(s):  
Carbon Dioxide ◽  
Molten Salts ◽  
Internal Diameter ◽  
Outer Diameter ◽  
Excessive Pressure ◽  
Carbon Particles ◽  
Ece Mechanism ◽  
Solid Phases ◽  
Cathodic Deposits ◽  
Crystalline Graphite

An electrochemical study of mechanisms of electrodeposition of carbon solid phases from halide melts (Na,K|Cl; Na,K,Cs|Cl), saturated with carbon dioxide under an excessive pressure of up to 1.5 MPa, has been carried out in the temperature range 550 - 850 °C by cyclic voltammetry. It has been found that the cathode process occurs in three steps at sweep rates of less than 0.1 Vs−1, and its electrochemical-chemical-electrochemical (ECE) mechanism is suggested. It has furthermore been found that cathodic deposits contain nano-sized carbon particles of different forms and structure: blocks of amorphous carbon, crystalline graphite, carbon nanotubes (CNT), and nanofibres. The outer diameter of the tubes is 5 - 250 nm, and the internal diameter is 2 - 140 nm. A correlation between the product structure and yield against electrolysis conditions and regimes has been established.

scholarly journals Continuous-flow Heck synthesis of 4-methoxybiphenyl and methyl 4-methoxycinnamate in supercritical carbon dioxide expanded solvent solutions

2013 ◽  
Vol 9 ◽  
pp. 2886-2897 ◽  
Author(s):  
Phei Li Lau ◽  
Ray W K Allen ◽  
Peter Styring
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Methyl Acrylate ◽  
Heck Reaction ◽  
Continuous Flow ◽  
Flow Reactor ◽  
Product Distribution ◽  
Internal Diameter ◽  
Palladium Metal ◽  
Supercritical Carbon

The palladium metal catalysed Heck reaction of 4-iodoanisole with styrene or methyl acrylate has been studied in a continuous plug flow reactor (PFR) using supercritical carbon dioxide (scCO2) as the solvent, with THF and methanol as modifiers. The catalyst was 2% palladium on silica and the base was diisopropylethylamine due to its solubility in the reaction solvent. No phosphine co-catalysts were used so the work-up procedure was simplified and the green credentials of the reaction were enhanced. The reactions were studied as a function of temperature, pressure and flow rate and in the case of the reaction with styrene compared against a standard, stirred autoclave reaction. Conversion was determined and, in the case of the reaction with styrene, the isomeric product distribution was monitored by GC. In the case of the reaction with methyl acrylate the reactor was scaled from a 1.0 mm to 3.9 mm internal diameter and the conversion and turnover frequency determined. The results show that the Heck reaction can be effectively performed in scCO2 under continuous flow conditions with a palladium metal, phosphine-free catalyst, but care must be taken when selecting the reaction temperature in order to ensure the appropriate isomer distribution is achieved. Higher reaction temperatures were found to enhance formation of the branched terminal alkene isomer as opposed to the linear trans-isomer.

Electrolytic synthesis of carbon nanotubes from carbon dioxide in molten salts and their characterization

2008 ◽  
Vol 40 (7) ◽  
pp. 2231-2237 ◽  
Author(s):  
I.A. Novoselova ◽  
N.F. Oliinyk ◽  
S.V. Volkov ◽  
A.A. Konchits ◽  
I.B. Yanchuk ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Carbon Nanotubes ◽  
Molten Salts ◽  
Synthesis Of Carbon Nanotubes

Numerical and Experimental Analysis of Twisted Tape Insert in Circular Tube

2019 ◽  
Author(s):  
V. S. Chandratre ◽  
A. A. Keste ◽  
N. K. Sane
Keyword(s):  
Heat Flux ◽  
Experimental Analysis ◽  
Test Section ◽  
Circular Tube ◽  
Uniform Heat Flux ◽  
Internal Diameter ◽  
Twisted Tape ◽  
Outer Diameter ◽  
Nusselt Numbers ◽  
Area Of Concern

Abstract Energy is a major area of concern for many industrial and engineering applications. For the development of energy efficient heat exchangers, heat transfer enhancement by passive inserts have growing research potential. The present study gives the numerical and experimental analysis of twisted tape insert in a circular tube for the range of Reynolds number between 5000 to 15000 with heat flux variation from 500W/m2 to 1.5 kW/m2 with air as working medium. A circular tube of 52.5 mm internal diameter, 60 mm outer diameter and 1000 mm length is used as test section with uniform heat flux. Twisted tape used is of Aluminum material having a pitch of 100 mm. Outside surface temperatures are measured at different locations on test section. Two ‘T’ type thermocouples are used to measure air temperature at inlet and outlet of test section. From numerical and experimental analysis it is observed that the Nusselt number increases for twisted tape as compared to smooth bare tube by 2.2–3.1 times. Again the Nusselt numbers obtained for smooth tube is compared with Dittus-Boelter and Gnielinski correlation and it is observed that the error is within acceptable limit of 10% variation. An error of 10% variation is observed in friction factor obtained by experimental analysis and Blasius and Petukov correlations.

scholarly journals Synthesis of highly dispersed calcium carbonate at excessive pressure of carbon dioxide

2019 ◽  
Vol 1348 ◽  
pp. 012038
Author(s):  
S Yu Bogoslovskii ◽  
A G Mechandin ◽  
V S Boldyrev ◽  
A S Kovalenko
Keyword(s):  
Carbon Dioxide ◽  
Calcium Carbonate ◽  
Excessive Pressure ◽  
Highly Dispersed

Experimental Study of the Reforming of Methane with Carbon Dioxide over Coal Char

2008 ◽  
Vol 6 (1) ◽  
Author(s):  
Yanbing Li ◽  
Rui Xiao ◽  
Baosheng Jin ◽  
Huiyan Zhang
Keyword(s):  
Carbon Dioxide ◽  
Flow Rate ◽  
Fixed Bed ◽  
Coke Oven ◽  
Fixed Bed Reactor ◽  
Internal Diameter ◽  
Generation System ◽  
Coke Oven Gas ◽  
Surface Areas ◽  
Conversion Of Methane

As one of the fundamental issues of the new poly-generation system on the basis of gasification gas and coke oven gas, carbon dioxide reforming of methane experiments have been performed over coal chars derived from different parent coals in a lab-scale fixed-bed reactor (internal diameter 12 mm, length 700 mm). The char derived from TongChuan coal exhibited higher activity than other samples employed under the same conditions. After the reforming reaction, the char samples were covered with different amounts of carbon deposition which resulted in the surface areas decrease. As the flow rate of feed gas increased from 200 ml/min to 600 ml/min over the Xuzhou char sample at 1050 degrees Celsius, the conversion of methane decreased from 52.7% to 17.5% and the H2 /CO dropped from 0.75 to 0.55. While maintaining the flow rate of CO2 at 20ml/min at 1050 degrees Celsius, the mole ratio of reactants CH4/CO2 was varied from 1 to 1.75 which led to the H2/CO ratio increase from 0.75 to 1.2.

A New Technology for Efficient, High Yield Carbon Dioxide and Water Transformation to Methane by Electrolysis in Molten Salts

2016 ◽  
Vol 1 (6) ◽  
pp. 1600092 ◽  
Author(s):  
Hongjun Wu ◽  
Deqiang Ji ◽  
Lili Li ◽  
Dandan Yuan ◽  
Yanji Zhu ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Molten Salts ◽  
New Technology ◽  
High Yield

scholarly journals RELAP5-3D Code Includes ATHENA Features and Models

2006 ◽  
Author(s):  
Richard A. Riemke ◽  
Cliff B. Davis ◽  
Richard R. Schultz
Keyword(s):  
Carbon Dioxide ◽  
Carbon Monoxide ◽  
Gas Phase ◽  
Molten Salts ◽  
Working Fluid ◽  
Hydraulic Systems ◽  
Sodium Potassium ◽  
Working Fluids ◽  
Noncondensable Gases ◽  
Magnetohydrodynamic Model

Version 2.3 of the RELAP5-3D computer program includes all features and models previously available only in the ATHENA version of the code. These include the addition of new working fluids (i.e., ammonia, blood, carbon dioxide, glycerol, helium, hydrogen, lead-bismuth, lithium, lithium-lead, nitrogen, potassium, sodium, and sodium-potassium) and a magnetohydrodynamic model that expands the capability of the code to model many more thermal-hydraulic systems. In addition to the new working fluids along with the standard working fluid water, one or more noncondensable gases (e.g., air, argon, carbon dioxide, carbon monoxide, helium, hydrogen, krypton, nitrogen, oxygen, sf6, xenon) can be specified as part of the vapor/gas phase of the working fluid. These noncondensable gases were in previous versions of RELAP5-3D. Recently four molten salts have been added as working fluids to RELAP5-3D Version 2.4, which has had limited release. These molten salts will be in RELAP5-3D Version 2.5, which will have a general release like RELAP5-3D Version 2.3. Applications that use these new features and models are discussed in this paper.

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