Specific Reactivities of Pure Carbon of Diverse Origins

Marsh, H.; Díez, M.A.; Kuo, K.

doi:10.1007/978-94-011-3310-4_11

Cited by 9 publications

(6 citation statements)

References 15 publications

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“…The sizes of the catalyst particles are comparable to the widths of the mesopores. This result is in agreement with the activation mechanism suggested by Marsh et al [140], whereby metal particles catalyze gasification in their vicinity via pitting or channeling processes, resulting in the development of mesopores and macropores. Interestingly, alongside the catalytic formation of mesopores, non-catalytic gasification occurs, leading to micropore development.…”

Section: Activated Carbons For Edlcsupporting

confidence: 93%

Activated Carbons and Their Evaluation in Electric Double Layer Capacitors

Kierzek

Gryglewicz

2020

Molecules

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This review presents a summary of the manufacturing of activated carbons (ACs) as electrode materials for electric double layer capacitors. Commonly used techniques of open and closed porosity determination (gas adsorption, immersion calorimetry, X-ray and neutrons scattering) were briefly described. AC production methods (laboratory and industrial) were detailed presented with the stress on advantages and drawbacks of each ones in the field of electrode materials of supercapacitor. We discussed all general parameters of the activation process and their influence on the production efficiency and the porous structure of ACs. We showed that porosity development of ACs is not the only factor influencing capacity properties. The role of pore size distribution, raw material origin, final carbon structure ordering, particles morphology and purity must be also taken into account. The impact of surface chemistry of AC was considered not only in the context of pseudocapacity but also other important factors, such as inter-particle conductivity, maximal operating voltage window and long-term stability.

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Section: Activated Carbons For Edlcsupporting

confidence: 93%

Activated Carbons and Their Evaluation in Electric Double Layer Capacitors

Kierzek

Gryglewicz

2020

Molecules

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“…The CO 2 -reactivity reaches a maximum value (R max ) at 1000 • C at the end of the dynamic step (21-24 min), decreasing as the reaction progresses in the isothermal step at 1000 • C in the oven and tending towards stability with gasification time due to less available sites per residual mass and more resistant to the CO 2 action. Such overall behavior obeys the well-known patterns of porous coal-based materials that depend on the access of CO 2 to the internal surface area of the in situ chars and the presence of catalytic species [44,45]. Figure 7 compares the reactivity and conversion profiles of the chars, and Table S6 reflects the differences and similarities of the different blends and coke by the most relevant CO 2gasification parameters derived from the mass change during the dynamic and isothermal steps.…”

Section: Co 2 -Gasification Behavior Using Thermogravimetrysupporting

confidence: 59%

Exploring Hydrochars from Lignocellulosic Wastes as Secondary Carbon Fuels for Sustainable Steel Production

Amado-Fierro,

Centeno,

Diez

2023

Materials

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This study investigates the suitability of different lignocellulosic sources, namely eucalyptus, apple bagasse, and out-of-use wood, for injection into blast furnaces (BFs). While wastes possess carbon potential, their high moisture renders them unsuitable for direct energy utilization. Additionally, the P and K impurities, particularly in apple bagasse, can pose operational and product quality challenges in BF. Thus, different thermochemical processes were performed to convert raw biomass into a more suitable carbon fuel. Low-temperature carbonization was selected for eucalyptus, yielding a biochar with properties closer to the low-rank coal. Hydrothermal carbonization was chosen for apple bagasse and out-of-use wood, resulting in hydrochars with enhanced fuel characteristics and fewer adverse inorganic species but still limiting the amount in binary PCI blends. Thermogravimetry evaluated the cause–effect relationships between coal and coal- and bio-based chars during co-pyrolysis, co-combustion and CO2-gasification. No synergistic effects for char formation were observed, while biochars benefited ignition and reactivity during combustion at the programmed temperature. From heat-flow data in combustion, the high calorific values of the chars were well predicted. The CO2-gasification profiles of in situ chars revealed that lignin-rich hydrochars exhibited higher reactivity and conversion than those with a higher carbohydrate content, making them more suitable for gasification applications.

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“…X-ray diffraction provides information regarding the extent of char crystallinity, in particular regarding the size of the carbon crystallites. Carbon crystal structure is known to be affected by heat treatment, with X-ray diffraction measurements showing increases in crystallite size as the heat treatment temperature of the char increases. ,, Furthermore, the proportion of char in a crystalline form has been shown to increase during isothermal reaction in oxygen . This is believed to be due to the preferential removal of the noncrystalline, more reactive components of the char matrix during reaction.…”

Section: Discussionmentioning

confidence: 99%

On the Effects of High Pressure and Heating Rate during Coal Pyrolysis on Char Gasification Reactivity

2003

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Effects of pyrolysis pressure on char reactivity remain a poorly understood aspect of the coal gasification process. In an attempt to address this problem, effects of pyrolysis pressure on char structure and reactivity are being investigated. In this paper, chemical reactivities to O2, CO2, and H2O of chars made from three Australian black coals were measured in a pressurized thermogravimetric analyzer, under conditions where chemical processes alone controlled reaction rates. These chars were prepared at a range of pyrolysis pressures, using pressurized flow reactors and an atmospheric pressure tube furnace, to ascertain any effects of devolatilization pressure and heating rate on the chemical reactivity of the resultant coal chars. It was found that while the apparent (as measured) reaction rate can be affected by pyrolysis pressure, the rate normalized to the char surface area (intrinsic rate) is much less affected, because of large effects of pyrolysis pressure on char micropore surface area. This finding was supported by measurements of char carbon crystallite dimensions that were unaffected by pyrolysis pressure increases. These results indicate that effects of pyrolysis pressure and heating rate on char gasification rates are more likely to be due to effects of structure and surface area and (depending on reaction conditions) the consequent effects on diffusion of reactants to the char surface, rather than on the intrinsic reactivity of the coal chars.

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Specific Reactivities of Pure Carbon of Diverse Origins

Cited by 9 publications

References 15 publications

Activated Carbons and Their Evaluation in Electric Double Layer Capacitors

Activated Carbons and Their Evaluation in Electric Double Layer Capacitors

Exploring Hydrochars from Lignocellulosic Wastes as Secondary Carbon Fuels for Sustainable Steel Production

On the Effects of High Pressure and Heating Rate during Coal Pyrolysis on Char Gasification Reactivity

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