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The potential for damage during the pyrolysis of phenolic/carbon composite material in the processing of carbon/carbon components is high. Accurately modeling the kinetics of the pyrolysis reaction could lead to improvements in processing. A mechanism for the pyrolysis of phenolic/carbon composite describing the reaction as occurring in three major regions is the foundation of a kinetic model. ...
The optical texture of cokes obtained at 500°C (60 minutes soak time) from a range of pitches, coal-tar and petroleum pitches and from the extrography fractions of three of the pitches, was related to the chemical composition of the parent material. Small differences observed in the amount of polyaromatic hydrocarbons and basic nitrogen polyaromatic compounds present in vacuum-distilled and thermally...
Microporous and activated carbons have numerous applications ranging from gas absorbers to liquid decolorizers and are often called carbon molecular sieves. Their properties depend critically on the size of their pores and pore openings. Their structures are very complex and have defied a description which can explain the structural changes which occur during the thermal or chemical treatments necessary...
Pyrolysis of acetylene over quartz plates coated with various metal catalysts resulted in the formation of all-carbon nanostructures which were observed directly by scanning electron microscopy (SEM). The nanotubes were studied in detail using transmission electron microscopy (TEM), and appear to grow as ultra-thin tubes with a central hollow core and considerable thickening due to secondary pyrolytic...
The SO 2 adsorption capacity of a series of chars obtained by N 2 pyrolysis at different temperatures from a low-rank coal with high ash content was assessed. The adsorption process was carried out at representative flue gas conditions (100°C adsorption temperature, 1 second residence time, 10% H 2 O v/v, 6% O 2 v/v, 1000 ppmv SO 2 ). Chars obtained by nitrogen...
A series of activated carbons has been prepared from the waste seed husks of the tropical multi-purpose tree Moringa oleifera, using a single-stage steam pyrolysis activation. Carbons were characterised by N 2 adsorption, CHN analysis and scanning electron microscopy. Nitrogen adsorption isotherms were analysed by the BET, t-plot and Horvath and Kawazoe methods. All the carbons were microporous,...
Spherical carbon nanobeads (solid and hollow) of two sizes of around 500–850 nm (large) and 250 nm (small) were synthesized by pyrolysing camphor vapour at 1000 °C in an argon atmosphere, using ferrocene, as catalyst, for the first time. The EEL spectrum suggests the carbon beads to be non-graphitic and these are covered by a graphitic shell of 80–100 nm, revealed by transmission electron microscopy...
Pyrolysis of benzene at ca 600–900 °C over Ni powder generated different types of carbon nanostructures possessing a wide range of morphologies. The effects of temperature and time on carbon nanotubes growth were evaluated. The deposited carbon yield was measured, and the quality of the nanotubes was analyzed by transmission electron microscopy (TEM).
High resolution electron microscopy (HREM) reveals that carbon nanotubes obtained by heating a polyethylene precursor in the presence of catalytic Ni particles have a structure consisting of stacked conical carbon layers. Two main types of nanotube structures were identified. When the conical angle along the tubes is in the range 16-35°, bamboo -shaped nanotubes are observed, characterized by...
Pyrolysis of hydrocarbon compounds on evaporated metal-based catalysts was used to produce carbon shells, hollow fibers and other hollow carbon forms. The carbon structures were investigated using transmission electron microscopy. A kinetic model for their formation and the mechanisms for obtaining different types of hollow carbons are proposed. In this model two competing processes, the linear...
Chars were prepared by heating rockrose (Cistus ladaniferus L) under dynamic and isothermal conditions between 200 and 1000 o C in nitrogen. Several techniques including chemical analysis, Fourier transform infrared (FTIR) spectroscopy, molecular simulation, density measurements, mercury porosimetry and adsorption were used to study the chemical structure and pore structure. The chars prepared...
The feasibility of preparing activated carbons from extracted oil palm fibre, an abundant oil palm waste, was studied. Preliminary tests were conducted to investigate the influences of different operating parameters, such as initial material size, inert gas flow rate, heating rate, pyrolysis temperature and hold time, on the properties of the pyrolysed chars. The pyrolysed chars were characterized...
Black liquor is a by-product which results from the pulping of wood in a solution of NaOH and Na 2 S, and accounts for a significant fraction of the total energy production in papermaking countries. Conventionally, the liquor is concentrated and burned in large recovery boilers, but pressurized gasification of black liquor is a promising alternative. A key concern for pressurized gasification...
A reactor is described for generating fullerenes from hydrocarbon gas or vapor. Distinguishing features are a thermal system in which the fullerene product is not exposed to destructive energetic photons (as in an arc) and ease of control. Acetylene was chosen as the first feedstock to reduce the hydrogen content. Argon is the carrier gas. The reactor is a radio-frequency induction heated cylinder...
Inter- and intra-layer disorder in a representative hard carbon derived from epoxy novolac resin at 1000°C have been investigated by comparing both the elastic structure factor S(Q) and radial distribution function obtained from pulsed neutron time-of-flight measurements with calculations from simple hypothetic systems with specific disorder characteristics. The spatial relationship between these...
The polymer was prepared by γ-ray induced polymerization in air and pyrolysis under argon at various temperatures in the range 600–900°C. The content in the carbon and oxygen increases at the expense of decreasing content in nitrogen and hydrogen. The ferromagnetic phase separated from the residue resulted by the pyrolysis of polyacrylonitrile has been analysed using Fourier transform infrared, X-ray...
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