Gas Reactions of Carbon

Walker, P.L.; Rusinko, Frank; Austin, L.G.

doi:10.1016/s0360-0564(08)60418-6

Cited by 601 publications

(344 citation statements)

References 82 publications

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“…Iron is known to influence the oxidation behavior of carbon materials because of its catalytic activity. 44,45 Previous experiments have shown that the oxidation temperature of carbon black can be reduced by ¾100°C by adding 1-2% iron particles. 46 Graphitized MWCNTs are more resistant against oxidation than the as-received MWCNTs.…”

Section: Resultsmentioning

confidence: 99%

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Monitoring oxidation of multiwalled carbon nanotubes by Raman spectroscopy

Osswald

Havel

Gogotsi

2007

J Raman Spectroscopy

569

367

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Multiwalled carbon nanotubes (MWCNTs) were oxidized in air and acids while varying the treatment time and/or temperature. The goal of this approach was to create the highest density of carboxyl groups with moderate sample loss, which is necessary for nanocomposite applications. In situ Raman experiments allowed real-time observation of the structural changes in MWCNTs upon oxidation. The ratio of the Raman intensities of the D and G bands was used to estimate the concentration of defects. It was found that while an oxidation for 6 h in H 2 SO 4 /HNO 3 provided the strongest effect, a 'flash oxidation' in air (15 min at 550°C) also leads to an efficient functionalization in a cost-effective and environmentally friendly way. Transmission electron microscopy, Fourier-transform infrared (FTIR) spectroscopy, thermogravimetric analysis and electrophoretic mobility analysis were used to study the oxidized nanotubes.

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Section: Resultsmentioning

confidence: 99%

“…This can be explained by the fact that the maximum catalytic effect of iron is reached at ¾1-3 wt.%, while a further increase in the iron concentration does not affect the reaction kinetics. 44,45 This iron can be removed by a subsequent HCl treatment.…”

Section: Resultsmentioning

confidence: 99%

Monitoring oxidation of multiwalled carbon nanotubes by Raman spectroscopy

Osswald

Havel

Gogotsi

2007

J Raman Spectroscopy

569

367

View full text Add to dashboard Cite

show abstract

“…Finally, the char activation (steam gasification) was performed to produce the final carbon products at 800-860°C in a 50% steam in nitrogen atmosphere. Gasification reaction at this temperature range is believed to be in the carbon-gas reaction Zone I1 (Walker, 1959)' that means activated carbon with fairly high surface area would be produced within a short period of reaction time.…”

Section: Carbon Productionmentioning

confidence: 99%

Novel carbons from Illinois coal for natural gas storage. Technical report, September 1--November 30, 1994

Rostam-Abadi¹,

Sun²,

Lizzio³

et al. 1994

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The goal of this project is to develop a technology for producing microengineered adsorbent carbons from Illinois coal and to evaluate the potential application of these novel materials for storing natural gas for use in emerging low pressure, natural gas vehicles (NGV). The focus of the project is to design and engineer adsorbents that meet or exceed the performance and cost targets established for low-pressure natural gas storage materials. Potentially, about two million tons of adsorbent could be consumed in natural gas vehicles by year 2000. If successful, the results obtained in this project could lead to the use of Illinois coal in a growing and profitable market that could exceed 6 million tons per year.During this reporting period, a pyrolysis-gasification reactor system was designed and assembled. Four carbon samples were produced from a -20+ 100 mesh size fraction of an Illinois Basin Coal (IBC-106) using a three-step process. The three steps were: coal oxidation in air at 250"C, oxicoal (oxidized coal) devolatilization in nitrogen at 425" C and char gasification in 50% steam-50% nitrogen at 860" C. These initial tests were designed to evaluate the effects of pre-oxidation on the surface properties of carbon products, and to determine optimum reaction time and process conditions to produce an activated carbon with high surface area. Nitrogen-BET surface areas of the carbon products ranged from 700-800 m2/g. Work is in progress topfurther optimize reaction conditions in order to produce carbons with higher surfacgare. G m z * PA few screening tests were made with a pressurized thermgravimetric sal-r a m an (PTGA) to evaluate the suitability of this instrument for obtaining qeth&& m+ adsorption isotherms at ambient temperature and pressures ranging from ow>to.&l G z atmospheres. The preliminary results indicate that PTGA can be used for b&h t g mm

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“…Mims et aln) have shown that the oxygen exchange is catalyzed by the potassium catalyst and occurs at the same sites as shown by Eqs. (19) and (20) in the case of uncatalyzed gasification. Also, product inhibition of gasification occurs through reversal of the oxygen exchange of actual site attacked by hydrogen.…”

Section: Effect Of Catalyst Content and Correlations Of Kinetic Parammentioning

confidence: 99%

Potassium catalyzed steam gasification of coal char in a pressurized stream of H2O-H2-CO mixture gas.

Tone

Kimura

Hino

et al. 1985

J. Chem. Eng. Japan

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Activated carbon produced from lignite char was impregnated with potassium carbonate and gasified with steam in an H2O-H2-CO mixture gas at total pressure of 1.5MPaand in the range of temperatures from 973 to 1073K.The gasification rate changed with the progress of carbon conversion and showed a maximumvalue at a carbon conversion around 0.3-0.4. The ratio of the gasification rate at any conversion to the initial rate could be correlated with the extent of carbon conversion by a relation which took into account the structural change of pores constructed in char filled with catalyst. The initial rate of gasification could be represented by a LangmuirHinshelwood type equation of single site mechanismincluding adsorption terms of H2Oand H2. The rate constant was found to be roughly proportional to the atomic ratio of potassium to carbon. The apparent activation energy was 97.8 kJ/mol, independently of the potassium content and carbon conversion.

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Gas Reactions of Carbon

Cited by 601 publications

References 82 publications

Monitoring oxidation of multiwalled carbon nanotubes by Raman spectroscopy

Monitoring oxidation of multiwalled carbon nanotubes by Raman spectroscopy

Novel carbons from Illinois coal for natural gas storage. Technical report, September 1--November 30, 1994

Potassium catalyzed steam gasification of coal char in a pressurized stream of H2O-H2-CO mixture gas.

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