• Journal of the Korean Solar Energy Society
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• v.23 no.3
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• pp.7-14
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• 2003

Absorption potential of desiccant solution significantly decreases after absorbing moisture from humid air, and a regeneration process requires a great amount of energy to recover absorption potential of desiccant solution. In an effort to develop an energy efficient regenerator, this study examines a regeneration process using hot air heated by solar radiation to recover absorption potential by evaporating moisture in liquid desiccant. More specifically, this study is aimed at finding the optimum operating condition of the regenerator by utilizing a well-established statistical tool, so-called response surface methodology(RSM), which may provide a functional relationship between independent and dependent variables. It is demonstrated that an optimization model to find the optimum operating condition can be obtained using the functional relationship between regeneration rate and affecting factors which is approximated on the basis experimental results.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.6
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• pp.168-175
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• 2008

In-use light duty diesel vehicles are considered as one of major sources of particulate emissions in many cities, and the start of the retrofit program for the light duty diesel vehicles is expected in near future in Korea. One of the problems of the retrofit of the light duty diesel vehicles is that the exhaust gas temperature is too low to apply passive regeneration DPF systems. This study introduces a catalytic combustor as a new active DPF regeneration technology. This study shows the principle and characteristics of DPF regeneration by the catalytic combustor and suggests it's proper control method for better regeneration.

• Clean Technology
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• v.16 no.4
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• pp.272-276
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• 2010

Adsorption process for the removal of acetylene, especially 2-butyne, from isoprene was studied with zeolite as an adsorbent. In this work, zeolite 5A was selected to investigate the effects of various regeneration conditions by repeated adsorption experiments. The effect of regeneration temperature and desorption pressure was investigated to identity the optimum regeneration conditions. Repeated adsorption and desorption experiments were carried out for 10 cycles to confirm the efficiency of regeneration process under temperature of 423 K and desorption time of 16 h.

• Journal of Environmental Science International
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• v.20 no.5
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• pp.647-653
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• 2011

Sediment cell is renewable energy which produces electric energy using immanent ingredients or reducing power of marine sediment as natural resources. Also the cell has an advantage that environmental pollution can be reduced through conversion of organic and inorganic contaminants into inert matter with generation of the energy. In this paper, we compared characteristics of electricity generation of the two different sediment cells, and investigated the regeneration effect of the sediment cells with manipulation of the sediment such as mixing and re-positioning. The results showed that 14.1 $W/m^2$ of power was obtained with the aluminum electrode, and the mixing of the sediment could increase the power by 4 $W/m^2$ compared to the control. Also, mixing the sediment has kept electricity for 4 weeks at a relatively constant level, which implied 'fuel regeneration effect'. Meanwhile, the sediment cell was proved to be effective in reduction of COD, which was up to 28.6%.

• Bulletin of the Korean Chemical Society
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• v.18 no.8
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• pp.811-814
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• 1997

An oxidative thermal regeneration process was developed and evaluated for its potential applicability in several environmental areas. The feasibility of the process is affected strongly by the gradual carbon loss, energy consumption, physical changes of carbon, and effective destruction efficiency of adsorbed materials during the regeneration. The aim of the study is to determine the optimum conditions to maintain acceptable destruction efficiency for adsorbed organics, controlling oxidant flow rate. Prior to its applications, various preliminary tests were carried out to determine the effects of experimental parameters on the process. The tests performed were reaction temperature, carbon loss, surface area, surface structure, and adsorptive property. The results of these tests show that the parameters are dependent on oxidant flow rate, and suggest that the process is comparable and, in some ways, possibly superior to conventional regeneration techniques because the oxidative process is a single step and less energy intensive.

• Bulletin of the Korean Chemical Society
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• v.20 no.12
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• pp.1447-1450
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• 1999

Countercurrent oxygen reaction (COR) was developed and evaluated for regeneration of exhausted activated carbon. Whether the regeneration technique is feasible or not is affected strongly by gradual loss and physical changes of activated carbon, energy consumption, and effective removal of adsorbed materials during the process. Various parameters such as reaction temperature, the loss of activated carbon, surface area, pore volume, surface structure, adsorptive property, etc. were examined to determine the effectiveness of COR. The results of these tests showed that the parameters were strongly dependent on oxidant flow rate, and suggest that the newly developed COR is comparable and, in some ways, possibly superior to conventional regeneration techniques because the overall process runs in a single step and is less energy intensive, and also because the adsorptive capacity of exhausted activated carbon was completely recovered.

• Journal of Energy Engineering
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• v.7 no.1
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• pp.73-80
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• 1998

Zinc titanate sorbents were prepared and regeneration of used sorbents for high temperature desulfurization of fuel gases was studied. Zn/Ti molar ratio of prepared sorbents was 1.5 and quartz fixed-bed reactors with 1 cm and 3 cm diameters were used. Regeneration of zinc titanate sorbents at high temperature is exothermic reaction; that brings about deterioration of sorbents. Therefore, we experimented regeneration reaction of zinc titanate sorbents for the purpose of obtaining the most suitable regeneration conditions by changing experimental parameters such as reaction temperature, oxygen concentration, flow rate and steam content. $H_2S$ and $SO_2$ breakthrough curves were obtained during desulfurization-regeneration. Also, properties of the sorbents before and after regeneration were analyzed using SEM, XRD, Hg-porosimetry and BET method. From such results, we obtained the most suitable regeneration conditions including regeneration temperature of 650$^{\circ}$C, $O_2$ content of 5% and steam content of 10% in the gas stream.

• Transactions of the Korean hydrogen and new energy society
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• v.24 no.5
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• pp.428-436
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• 2013

Attrition characteristics of $CO_2$ absorbents for pre-combustion $CO_2$ capture were investigated to check attrition loss of those absorbents and to determine solid circulation direction and the better $CO_2$ absorbent. The cumulative attrition losses of two absorbents increased with increasing time. However, attrition loss under a humidified condition was lower than that under a non-humidified condition case. Between two absorbents, attrition loss of PKM1-SU absorbent was higher than that of P4-600 absorbent. The average particle sizes of the attrited particles were less than $2.5{\mu}m$ for two absorbents under a non-humidified condition case, and therefore, we could conclude that the main mechanism of attrition for two absorbents is not fragmentation but abrasion. Based on the results from the test for the effect of humidity on the attrition loss, we selected solid circulation direction from SEWGS reactor to regeneration reactor because the SEWGS reactor contains more water vapor than regeneration reactor. Attrition loss and make-up rate of two absorbents were compared based on the results from $CO_2$ sorption capacity tests and attrition tests. Required make-up rate of P4-600 absorbent was lower than that of PKM1-SU absorbent. However, more detail investigation on the optimum regeneration temperature, manufacturing cost, solid circulation rate, regeneration rate, and long-term sorption capacity should be considered to select the best $CO_2$ absorbent.

• Journal of Environmental Science International
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• v.17 no.5
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• pp.493-500
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• 2008

This paper describes the adsorption/desorpton efficiency of a modified activated carbon by irradiated microwave to treat toluene. By employing microwave energy, the regeneration time was considerably shortened compared with conventional thermal heating regeneration. New adsorbent called ACB (Activated Carbon-Bentonite) was prepared from powder activated carbon with mixing bentonite as a binder. Specific surface area, average pore size and total pore volume of ACB were calculated from the nitrogen adsorption/desorption isotherm. The surface of ACB was characterized with scanning electron microscope(SEM). The results showed that the specific surface area, total pore volume, average pore size of ABC was not influenced by regenerating cycle with microwave irradiation. Toluene was adsorbed onto ACB which desorbed by MW irradiation. Absorption capacity of ACB was 0.117 $g_{toluene}/g_{ACB}$. Desorption efficiency of toluene increased as higher microwave output was applied.

• 한국태양에너지학회:학술대회논문집
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• 2009.04a
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• pp.155-161
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• 2009

Desiccant systems have been proposed as energy saving alternatives to vapor compression air conditioning for handling the latent load. Use of liquid desiccants offers several design and performance advantages over solid desiccants, especially when solar energy is used for regeneration. The liquid desiccants contact the gas inside the packed column and the heat transfer and mass transfer will occur. This proposal is try study the mass transfer and heat transfer inside the packed column of dehumidifier and regenerator systems. And later on, the rates of dehumidification and regeneration that were affected by desiccant flow rates, air temperature and humidity, and desiccant temperature and all that variation will influence the performance of the systems.