• Resources Recycling
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• v.24 no.6
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• pp.3-8
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• 2015

Gasification characteristics and gas produced from a sewage sludge char were analyzed by using a thermobalance reactor, which is used for a reaction kinetic analysis by measuring weight change of materials at a desired temperature. Gasification reaction rate increased with increasing temperature and steam partial pressure due to the promotion of gasification reaction. Three models of gas-solid reaction were applied to the reaction kinetics analysis and modified volumetric reaction model was an appropriated model for the steam gasification of the sewage sludge char. Apparent activation energy and pre-exponential factors were evaluated as 155.5 kJ/mol and $14,087s^{-1}atm^{-1}$, respectively. The order of reaction on steam partial pressure was 0.68. Gas analysis was performed at $900^{\circ}C$ and hydrogen concentration was highest in the gas concentrations, which increased with increasing the steam partial pressure. Hydrogen concentration increased the most and hydrogen concentration in the produced gas was 2-4 times higher than that of carbon monoxide due to the gasification and water gas shift reaction.

• Proceedings of the Korean Fiber Society Conference
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• 2003.04a
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• pp.98-100
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• 2003

The efficiency of the adsorption of adsorbents depends on both pore size and shape. In other to adsorb hydrated ion in application of electric double layer capacitor (EDLC), mesopore is necessary[1,2]. Tamai et al.[3] reported that an increased portion of mesopore was introduced through addition of metal or organometallic compound in the precursor and following activation of the carbon fibers with steam. (omitted)

• Carbon letters
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• v.2 no.3_4
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• pp.176-181
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• 2001

A series of activated carbons were prepared from coconut shells and coal-tar pitch binder by physical activation with steam in this study. The effect of variable processes such as activation temperature, activation time and ratio of mixing was investigated for optimizing those preparation parameters. The activation processes were carried out continuously. The nitrogen adsorption isotherms at 77 K on pellet-shaped activated carbons show the same trend of Type I by IUPAC classification. The average pore sizes were about 19-21${\AA}$. The specific surface areas ($S_{BET}$) of pellet typed ACs increased with increasing the activation temperature and time. Specific surface area of AC treated for 90 min at temperature $900^{\circ}C$ was 1082 $m^2/g$. The methylene blue numbers continuously increased with increasing the activation temperature and time. On the other hand, iodine numbers highly increased till activation time of 60 min, but the rate of increase of iodine numbers decreased after that time. This indicates that new micropores were created and the existing micropores turned into mesopores and macropores because of increased reactivity of carbon surface and $H_2O$.

• Proceedings of the Korean Fiber Society Conference
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• 2001.10a
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• pp.303-305
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• 2001

Porous carbons have beef used as adsorbents, filters, catalyst supports, etc. due to well-development pore structure. Porous carbons can be prepared by two different activation processes i.e. physical activation by steam or CO$_2$, and chemical activation by KOH, H$_3$PO$_4$ etc. from various raw material. Recently, agricultural wastes such as rice hulls [1], coconut shell [2-31 and straws [4] are growing interest as precursors fur porous carbons due to its easy availability and cheapness. (omitted)

• Clean Technology
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• v.25 no.2
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• pp.129-139
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• 2019

Bamboo is an evergreen perennial plant, and it is known as one of the most productive and fastest-growing plants in the world. It grows quickly in moderate climates with only moderate water and fertilizer. Traditionally in Asia, bamboo is used for building materials, as a food source, and as versatile raw materials. Bamboo as a biomass feedstock can be transformed to prepare activated carbon using the thermal treatment of pyrolysis. The effect of process variables such as carbonization temperature, activation temperature, activation time, the amount of steam, and the mixing ratio of phosphoric acid and bamboo were systematically investigated to optimize the preparation conditions. Steam activation was proceeded after carbonization with a vapor flow rate of $0.8{\sim}1.8mL-H_2O\;g-char^{-1}\;h^{-1}$ and activation time of 1 ~ 3 h at $700{\sim}900^{\circ}C$. Carbon yield and surface area reached 2.04 ~ 20.59 wt% and $499.17{\sim}1074.04m^2\;g^{-1}$, respectively, with a steam flow rate of $1.4mL-H_2O\;g-char^{-1}\;h^{-1}$ for 2 h. Also, the carbon yield and surface area were 24.67 wt% and $1389.59m^2\;g^{-1}$, respectively, when the bamboo and phosphoric acid were mixed in a 1:1 weight ratio ($700^{\circ}C$, 2 h, $1.4mL-H_2O\;g-char^{-1}\;h^{-1}$). The adsorption of methylene blue into the bamboo activated carbon was studied based on pseudo first order and second order kinetics models. The adsorption kinetics were found to follow the pseudo second order model, which is governed by chemisorption.

• Transactions of the Korean hydrogen and new energy society
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• v.13 no.3
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• pp.214-223
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• 2002

Kinetic and effectiveness factors for methanol steam reforming using commercial copper-containing catalysts in a plug flow reactor were investigated over the temperature ranges of $180-250^{\circ}C$ at atmospheric pressure. The selectivity of $CO_2$/$H_2$ was almost 100%, and CO products were not observed under reaction conditions employed in this work. It was indicated that $CO_2$ was directly produced and CO was formed via the reverse water gas shift reaction after methanol steam reforming. The intrinsic kinetics for such reactions were well described by the Langmuir-Hinshelwood model based on the dual-site mechanism. The six parameters in this model, including the activation energy of 103kJ/mol, were estimated from diffusion-free data. The significant effect of internal diffusion was observed for temperature higher than $230^{\circ}C$ or particle sizes larger than 0.36mm. In the diflusion-limited case, this model combined with internal effectiveness factors was also found to be good agreement with experimental data.

• Journal of the Korean Society for Railway
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• v.13 no.4
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• pp.357-362
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• 2010

The railroad that represents modern industry began appearing in 1899. However, after the steam locomotive that provided water stopped the service, the water towers within the railroad station were useless. Suggestions presented in this study for activating the environment around the water towers that are designated as the cultural properties results are as followed: 1) The place where people can experience the vestiges of Korean War and the region that different novels accommodated. 2) A plaza 3) A facility for exhibition of industry inheritance and local products 4) A local landmark 5) Reproduction of the historical steam locomotive and water tower Local residents should participate in the activation process. And the designer should consider the environmental context. In addition, the activation of water towers should be designed under an urban plan.

• Transactions of the Korean hydrogen and new energy society
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• v.25 no.5
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• pp.459-467
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• 2014

The catalytic steam reforming of toluene, a major component of biomass tar, was studied using several catalysts at various temperatures $400-800^{\circ}C$, kind of metal, and metal loading content. Ru and K promoted Ni-base catalyst were prepared, and used for steam reforming of toluene with steam/toluene molar ratio of 25. Concentration of toluene in reactant flow is $30g/Nm^3$ that is usual content of tar from biomass gasifier. The result from experiments showed that $H_2$ content in product gas and toluene conversion increased with temperature. Where in high temperature range, CO and $CO_2$ content in product gas were affected mainly by Boudouard reaction. Ni/Ru-K(3wt%)/$Al_2O_3$ catalyst showed best performance on steam reforming of toluene than used catalysts in this study at whole temperature. Catalysts have been characterized by XRD, TG. XRD analysis displayed that Ni particle size on Ni/Ru-K (3wt%)/$Al_2O_3$ catalyst was 29.4nm. Activation energy of Ni/Ru-K (3wt%)/$Al_2O_3$ catalyst was calculated 36.8kJ/mol by Arrhenius plot.

• Transactions of the Korean hydrogen and new energy society
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• v.23 no.6
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• pp.647-653
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• 2012

We have investigated the kinetics and activity of waste catalysts for steam-lignite gasification. Waste catalysts I, II, III and reference $K_2CO_3$ were used and physical mixed with a coal. The gasification experiments were carried out with the low rank coal loaded with 1 wt% and 5 wt% catalyst at the temperature range from 700 to $900^{\circ}C$ using thermobalance reactor. It was observed that the carbon conversion reached almost 100% regardless of the kinds of catalysts at $900^{\circ}C$. The shortest time to reach the designated conversion was obtained for 1 wt% waste catalyst II and 5 wt% $K_2CO_3$ at $900^{\circ}C$. The gasification reaction rate constant increased with increasing the temperature. Highest rate constant was obtained with $K_2CO_3$ at $900^{\circ}C$. The lowest activation energy was 69.42 kJ/mol for 5 wt% waste catalyst II. The waste catalyst had an influence on the reduction of activation energy.

• Applied Chemistry for Engineering
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• v.20 no.1
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• pp.109-115
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• 2009

The purposes of this study are to treat sewage sludge that has increasingly become an issue and to recycle it as the adsorbent. The adsorbent was produced by carbonization and simultaneous steam activation, and its characteristics were studied. Parametric screening studies were carried out for the preparation of good adsorbent. Optimum operating conditions were confirmed as input carbonization-activated temperature of $840^{\circ}C$, feed steam flow rate of 70 g/min, carbonization-activated time of 30 min and feed dried sludge of 10.8 kg/day, respectively. At this time, the iodine adsorptivity was maximized as 328.1 mg/g. Pore development, structure, element compound and content were confirmed by using nanoPOROSITY, SEM (Scanning electron microscope), and EDS (Energy dispersive spectroscopy). Through this result, it was known that the adsorbent derived from sewage sludge could be used for the treatment of leachate in a landfill, VOCs (Volatile organic compounds), and so on.