Carbonaceous solids

Carbonaceous solids also reach Earth in the form of organic and icy materials that condensed in the cold outer regions of the solar nebula and also as organic materials preserved in interstellar grains. 

The beneficial effects are demonstrated of heterogeneous secondary pyrolysis reactions on the liquid products of PU pyrolysis. Pyrolysis volatiles are passed through a packed bed of carbonaceous solids that promote the secondary reactions. Activated carbon and reaction injection moulded PU (RIM) char were found to be suitable bed materials. The long-term object was to develop marketable solid products by pyrolysis of wastes, so obtaining high char yields. In addition to affecting the liquid products, RIM char also increased the total char... 

Carbonaceous solids appear as a result of retrogressive reactions, in which organic thermal fragments recombine to produce insoluble semi-cokes (59,65). Coke formation is observed during liquefaction of all coals and its extent can vary widely according to the coal, the reaction solvent, and reaction conditions. The predominant inorganic species produced during the process of coal... 

For these types of reactor solids, the carbonaceous solids content varies usually from about 20 to 40%. The components of these solids are listed in Table VII. Optical examination of the solids has shown that they are primarily composed of mixtures of semi-cokes formed during liquefaction by retrogressive reactions with chars derived from macerals. Unreacted macerals comprise only a small fraction of these solids (65,74,75). 

Once a carbonaceous solid or liquid material is converted to a gaseous state, undesirable substances such as sulfur compounds and ash may be removed from the gas. In contrast to combustion processes, which work with excess air, gasification processes operate at substoichiometric conditions with the oxygen supply controlled (generally 35 percent of the... 

Investigators have used the words carbon and soot to describe a wide variety of carbonaceous solid materials, many of which contain appreciable amounts of hydrogen as well as other elements and compounds that may have been present in the original hydrocarbon fuel. The properties of the solids change markedly with the conditions of formation and, indeed, several quite well-defined varieties of solid carbon may be distinguished. One of the most obvious and important differences depends on how the carbon is formed carbon may be formed by a homogeneous vapor-phase reaction it may be deposited on a solid surface that is present in or near the reaction zone or it may be generated by a liquid-phase pyrolysis. 

Demirbas, A. 2008b. Hydrogen production from carbonaceous solid wastes by steam reforming. Energy Sources Part A 30 924-931. 

Presented here is a concise description of surface immobilization of DNA, oligonucleotides, and DNA derivatives by adsorption onto carbonaceous materials, and the properties of the DNA layer adsorbed on carbonaceous solid phase. 

Biomass is another material that can produce a mixture of carbonaceous solid and liquid products as well as gas ... 

A typical firebox temperature is 1500°F. Thus, the heater tubes can reach 1300°F on loss of the process flow, even though the fuel flow has been immediately stopped. Tubes with a low chrome content may bend and distort as a result of such overheating. Even at 1000°F, residual liquid left in the tubes when flow is lost may thermally degrade to a carbonaceous solid or heavy polymer that fouls the interior of the tubes. 

Belford RL, Clarkson RB (1993) In Botto R, Sanada Y (eds) Techniques in Magnetic Resonance for Carbonaceous Solids, ACS Advances in Chemistry Series 229, American Chemical Society, Washington, p 107... 

Adachi, Y., and Nakamizo, M. 1993 In Magnetic Resonance of Carbonaceous Solids,... 

Jurkiewicz, A., Bronnimann, C. E., and Maciel, G. E. 1993 In Magnetic Resonance of Carbonaceous Solids, R. E. Botto and Y. Sanada (Editors). Oxford University Press, Oxford. 

In contrast to gas-phase carbonization, most thermosetting resins, such as phenol-formaldehyde and furfuryl alcohol, and also cellulose can be converted to carbon materials by solid-phase carbonization. When the carbonization of most of these precursors proceeds rapidly, the resultant carbon materials become porous. If the carbonization is performed so slowly that the resultant carbonaceous solids can shrink completely, the so-called glass-like carbons are produced, which contain a large number of closed pores. 

We successfully demonstrated that hydrogen could be efficiently produced by catalytic steam reforming of carbohydrate-derived bio-oil fractions in a fluidized bed reactor using a commercial nickel-based catalyst. Greater steam excess than that used for natural gas reforming was necessary to minimize the formation of char and coke (or to gasify these carbonaceous solids) resulting from thermal decomposition of complex carbohydrate-derived compounds. 

Effective engineering design of the cracking reactor for waste plastic processing is very important since the carbonaceous solid residue is one of the cracking products (levels up to 10% or more) and its continuous removal from the reactor is necessary to ensure profitable running. Stirred vessel reactors which have augers in the bases to facilitate continuous char removal are presented. 

This work focuses on the application of water adsorption to the characterisation of narrow microporosity (uitramicroporosity) on carbon molecular sieves (CMS). In addition, the mechanism of water adsorption in carbonaceous solids is analysed. Despite of the presence of surface groups in these materials, they present low adsorption at low relative pressures (P/Po <0.2), indicating the significant role of micropore size in the starting of water adsorption. Interestingly, it has been seen that water adsorbs even on samples, which do not present CO2 adsorption. 

In previous studies, we have investigated water adsorption in activated carbon fibres (ACFs), which are mainly microporous solids with a well-defined pore structure, and some activated carbons (AC) containing micro, meso and macroporosity [9,10]. On all these materials, we were able to show that water adsoiption in micropores depends on the micropore size, taking place gradually according to the pore size. It was concluded that adsorbed water in microporosity is in a solid, ice-like phase, with a density around 0.92 g.cm The present paper presents the results corresponding to the extension of this research to CMS, studying both the mechanism of water adsorption in carbonaceous solids and the suitability of water adsorption to characterise CMS. 

Energetics and Mechanism of Physical Sorption by Carbonaceous Solids Evaluation of surface area and porosity factors. 

---