scholarly journals Synthesis of Carbon Nanotubes from Benzene in a Fluidised Bed Reactor

2020 ◽  
Vol 22 (3) ◽  
pp. 235
Author(s):  
G.T. Smagulova ◽  
B.B. Kaidar ◽  
N. Yesbolov ◽  
N.G. Prikhodko ◽  
N.R. Maxumzhanova
Keyword(s):  
Carbon Nanotubes ◽  
Gas Flow ◽  
Nickel Nanoparticles ◽  
Fluidised Bed ◽  
Optimum Temperature ◽  
Solution Combustion ◽  
Flow Rates ◽  
Method Of Solution ◽  
Fluidised Bed Reactor ◽  
Synthesis Of Carbon Nanotubes

The paper presents the results of carbon nanotubes synthesis from benzene in fluidised bed reactor. Al2O3 spheres with iron and nickel nanoparticles coating were used as a catalyst for the synthesis of carbon nanotubes. To deposit nickel nanoparticles on the surface of Al2O3 spheres, the method of solution combustion was used. Optimum temperature conditions and gas flow rates were worked out for each of the catalysts. It was found that the best efficiency in the synthesis of carbon nanotubes from benzene is shown by catalysts based on aluminium oxide coated with iron. The obtained carbon nanotubes were studied by scanning electron microscopy and Raman spectroscopy. It was found that at temperatures above 850 °C from benzene on Al2O3 spheres with Ni/NiO, carbon frame structures are formed.

scholarly journals Synthesis of carbon nanotubes on alumina-based supports with different gas flow rates by CCVD method

2006 ◽  
Vol 26 ◽  
pp. 135-138 ◽  
Author(s):  
R Aghababazadeh ◽  
A R Mirhabibi ◽  
H Ghanbari ◽  
K Chizari ◽  
R M Brydson ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Gas Flow ◽  
Flow Rates ◽  
Synthesis Of Carbon Nanotubes

Activation of Nanoflows for Fuel Cells

2012 ◽  
Vol 3 (2) ◽  
Author(s):  
Z. Insepov ◽  
R. J. Miller
Keyword(s):  
Carbon Nanotubes ◽  
Fuel Cells ◽  
Surface Waves ◽  
Traveling Waves ◽  
Gas Flow ◽  
Atomic Mass ◽  
Flow Rates ◽  
Selective Filter ◽  
Phase Velocities ◽  
Dynamics Simulations

Propagation of Rayleigh traveling waves from a gas on a nanotube surface activates a macroscopic flow of the gas (or gases) that depends critically on the atomic mass of the gas. Our molecular dynamics simulations show that the surface waves are capable of actuating significant macroscopic flows of atomic and molecular hydrogen, helium, and a mixture of both gases both inside and outside carbon nanotubes (CNT). In addition, our simulations predict a new “nanoseparation” effect when a nanotube is filled with a mixture of two gases with different masses or placed inside a volume filled with a mixture of several gases with different masses. The mass selectivity of the nanopumping can be used to develop a highly selective filter for various gases. Gas flow rates, pumping, and separation efficiencies were calculated at various wave frequencies and phase velocities of the surface waves. The nanopumping effect was analyzed for its applicability to actuate nanofluids into fuel cells through carbon nanotubes.

Gasification Kinetics of Victorian Brown Coal-Derived Char in Fluidised Bed Reactor

2021 ◽  
pp. 1-24
Author(s):  
Imtenan Sayeed ◽  
Mahmud Arman Kibria ◽  
Sankar Bhattacharya
Keyword(s):  
Activation Energy ◽  
Brown Coal ◽  
Gas Flow ◽  
Oxygen Carrier ◽  
Fluidised Bed ◽  
Co2 Partial Pressure ◽  
Fuel Reactor ◽  
Char Particle ◽  
Fluidised Bed Reactor ◽  
Kinetics Of

Abstract In a chemical looping combustion (CLC) system, gasification kinetics of char holds immense importance being the rate-limiting reaction in the fuel reactor. This paper studied the gasification kinetics of char derived from Victorian Brown Coal (VBC) in a fluidised bed reactor which mimics the fuel reactor conditions of a CLC process. Mass of char, char particle size and gas flow conditions were optimised to ensure the gasification reaction free from mass transfer limitations. Effect of oxygen carrier, hematite, being the bed material was also studied. The experiments were conducted in the temperature range of 800C-950C, which is a typical range for fuel reactor. The experimental results were modelled with the help of grain model (GM) and random pore model (RPM) to analyse the kinetic parameters. Activation energy was found to be around 177 kJ/mol in sand bed and 175.5 kJ/mol in the hematite bed. Reaction in hematite bed was found to be 42% faster on average compared to the reaction in a sand bed. Fastest total conversion of char took as low as 4.1 minutes in hematite bed at 950C. While catalytic effect of hematite was ruled out due to insignificant change in activation energy, it was concluded that increase in CO2 partial pressure at the vicinity of char particle enhanced the reaction rate in the case of hematite bed. This study has generated relevant information for the CLC of Victorian Brown Coal with hematite as the oxygen carrier.

Fluidised-bed CVD synthesis of carbon nanotubes on Fe2O3/MgO

2003 ◽  
Vol 12 (3-7) ◽  
pp. 780-785 ◽  
Author(s):  
Ph. Mauron ◽  
Ch. Emmenegger ◽  
P. Sudan ◽  
P. Wenger ◽  
S. Rentsch ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Fluidised Bed ◽  
Cvd Synthesis ◽  
Synthesis Of Carbon Nanotubes

Catalyst Assisted Synthesis of Carbon Nanotubes Using the V-Shaped Pyrolysis Flame Method

2009 ◽  
Vol 79-82 ◽  
pp. 2123-2126 ◽  
Author(s):  
Yuan Chao Liu ◽  
Bao Min Sun ◽  
Zhao Yong Ding
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Gas Flow ◽  
Hydrogen Gas ◽  
Catalyst Precursor ◽  
Shaped Body ◽  
Helium Gas ◽  
The Rich ◽  
Central Pipe ◽  
Synthesis Of Carbon Nanotubes

Flames offer potential for synthesis of carbon nanotubes(CNTs) in large quantities at considerably lower costs than that of other methods currently available. Synthesis CNTs from V-shaped pyrolysis flame is a kind of novel technique. This study aims to examine conditions for CNTs formation in V-shaped pyrolysis flame. Synthesis inner the V-shaped body and providing heat outer is distinct characteristic in the method. A premixed carbon monoxide/hydrogen gas diluted by helium gas flow was introduced into V-shaped body bottom centre. Simultaneously, as catalyst precursor, pentacarbonyl iron was entrained after ultrasonic atomization into the central pipe by helium gas flow. The rich acetylene/air premixed gas, providing heat source, was introduced into V-shaped body outside surface. Scanning electron microscopy and transmission electron microscopy images of the carbon products were examined. Large quantities of CNTs with the less carbon impurities were formed in the process. Carbon nanotubes can grow well when the sampling time was 5 minutes.A nanotube formation ‘window’ is evident with formation limited to fuel equivalence ratios between 1.6 and 1.8. Furthermore, temperature range was from 850°C to 950°C.Nanoparticles associated with nanotube bundles were identified as primarily ferric oxide.

scholarly journals Evaluation of a Humidified Nasal High-Flow Oxygen System, Using Oxygraphy, Capnography and Measurement of Upper Airway Pressures

2011 ◽  
Vol 39 (6) ◽  
pp. 1103-1110 ◽  
Author(s):  
J. E. Ritchie ◽  
A. B. Williams ◽  
C. Gerard ◽  
H. Hockey
Keyword(s):  
Healthy Volunteers ◽  
Airway Pressure ◽  
Gas Flow ◽  
Air Entrainment ◽  
High Flow ◽  
Positive Pressure ◽  
Mean Airway Pressure ◽  
Flow Rates ◽  
Oxygen Fraction ◽  
Airway Pressures

In this study, we evaluated the performance of a humidified nasal high-flow system (Optiflow™, Fisher and Paykel Healthcare) by measuring delivered FiO2 and airway pressures. Oxygraphy, capnography and measurement of airway pressures were performed through a hypopharyngeal catheter in healthy volunteers receiving Optiflow™ humidified nasal high flow therapy at rest and with exercise. The study was conducted in a non-clinical experimental setting. Ten healthy volunteers completed the study after giving informed written consent. Participants received a delivered oxygen fraction of 0.60 with gas flow rates of 10, 20, 30, 40 and 50 l/minute in random order. FiO2, FEO2, FECO2 and airway pressures were measured. Calculation of FiO2 from FEO2 and FECO2 was later performed. Calculated FiO2 approached 0.60 as gas flow rates increased above 30 l/minute during nose breathing at rest. High peak inspiratory flow rates with exercise were associated with increased air entrainment. Hypopharyngeal pressure increased with increasing delivered gas flow rate. At 50 l/minute the system delivered a mean airway pressure of up to 7.1 cmH2O. We believe that the high gas flow rates delivered by this system enable an accurate inspired oxygen fraction to be delivered. The positive mean airway pressure created by the high flow increases the efficacy of this system and may serve as a bridge to formal positive pressure systems.

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