• Title/Summary/Keyword: fixed carbon

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Study on the Dissolution Characteristics of Liquid $CO_2$ Released by Fixed Pipeline (고정 파이프라인에서 분사된 액체 이산화탄소 용해특성 연구)

  • 김남진;김종보
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.16 no.9
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    • pp.863-871
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    • 2004
  • The use of fossil fuels like coal, oil and natural gases around the world causes an increase of the carbon dioxide content in the atmosphere. In order to reduce the concentration of the greenhouse gas, the idea of carbon dioxide sequestration in the ocean is proposed to be an effective mitigation strategy to counteract potential global warming due to the greenhouse effect. Therefore, in the present study, calculations of the dissolution behavior of carbon dioxide when liquid carbon dioxide is released at 1,000m and 1,500m in depth by fixed pipeline are performed. The results show that carbon dioxide droplets change to carbon dioxide bubbles in gas phase around 500m in depth, and the droplets are completely dissolved below 500 m in depth if the liquide carbon dioxide is released both at 1,000 m in depth with the initial diameter of 0.007m or less and at 1,500m in depth with the diameter of 0.011m or less.

Analysis of Breakthrough Curves and Mass Transfer Resistance for Phenol Adsorption in a Fixed-bed Process Packed with Activated Carbon (활성탄을 충전한 고정층에서 페놀 흡착에 따른 파과곡선과 물질전달저항 해석)

  • You, Hae-Na;Kam, Sang-Kyu;Lee, Min-Gyu
    • Journal of Environmental Science International
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    • v.23 no.1
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    • pp.53-60
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    • 2014
  • Adsorption of phenol on activated carbon in a fixed bed was studied. The effects of fixed-bed length, superficial velocity (flow rate) and particle size of adsorbent on fixed-bed performance were investigated. Some characteristic parameters such as the breakthrough time ($t_{0.05}$), saturation time ($t_{0.95}$), length of mass transfer zone ($L_{MTZ}$), adsorptive capacity (W), and adsorption rate constant ($K_a$) were derived from the breakthrough curves. Adsorbent particle sizes significantly affected the shape of the breakthrough curve. Larger particle sizes resulted in an earlier breakthrough, a longer $L_{MTZ}$ and a lower adsorption rate. Superficial velocity was a critical factor for the external mass transfer during fixed-bed adsorption process. The external mass transfer resistance was dominant as increasing superficial velocity.

Adsoption Removal of PCBs by Activated Carbon (활성탄에 의한 PCBs의 흡착제거)

  • Yu, Yong-Ho;Lee, Jong-Jig
    • Journal of the Korean Society of Safety
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    • v.21 no.1 s.73
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    • pp.59-64
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    • 2006
  • In this study, adsorption characteristics of PCBs on granular activated carbon were experimentally investigated in a batch reactor and in a fixed bed reactor. Granular activated carbon removed above 98.4% of initial concentration, 1000mg/L, of PCBs. It was estabilished that the adsorption equilibrium of PCBs on granular activated carbon was more successfully fitted by Freundlich isotherm equation in the concentration range from 1 to 1000mg/L. Because Freundlich parameter, ${\beta}$ is 0.346, removall treatment of PCBs by activated carbon accounts for the fact that toxicity reduction can be achieved through this process. Appearance time of breakthrough curve is faster with the increase flow rate and inflow concentration of liquid. The utility of granular activated carbon is enhanced with the increase of bed height and with the decrease of inflow rate.

Study on Adsoption Characteristics of Tharonil on Activated Carbon Fixed Bed (활성탄 고정층에 대한 Tharonil의 흡착특성에 관한 연구)

  • Lee, Jong-Jip;Yu, Yong-Ho
    • Journal of the Korean Society of Safety
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    • v.17 no.1
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    • pp.54-60
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    • 2002
  • To obtain the breakthrough characteristics for the design of fixed bed adsorption plant, adsorption experiment on granular activated carbon was performed with tharonil in the fixed bed. The pore diffusivity and surface diffusivity of tharonil estimated by the concentration-time curve and adsorption isotherm were $D_s=2.825{\times}10^{-9}cm^2/s,\;D_p=1.26{\times}10^{-5}cm^2/s$, respectively. From comparison of the pore diffusivity and surface diffusivity, it was found that surface diffusion was controlling step for intrapaticle diffusion. The breakthrough curve predicted by constant pattern-linear driving force model were shown to agree with the experimental results. The surface diffusivity and film mass transfer coefficient had no effect on the theoretical breakthrough curve but the adsorption isotherm had fairly influence on it. Appearance time of breakthrough curve is faster with the increase flow rate and inflow concentration of liquid. The utility of granular activated carbon is enhanced with the increase of bed height and with the decrease of inflow rate.

Removal of Phenol by Granular Activated Carbon from Aqueous Solution in Fixed-Bed Adsorption Column : Parameter Sensitivity Analysis (충진층 흡착관 내에서 입상활성탄에 의한 페놀 제거 : 매개변수 감응도 해석)

  • 윤영삼;황종연;권성헌;김인실;박판욱
    • Journal of Environmental Science International
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    • v.7 no.6
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    • pp.773-782
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    • 1998
  • The adsorption experiment of phenol(Ph) from aqueous solution on granular activated carbon was studied in order to design the fixed-bed adsorption column. The experimental data were analyzed by unsteady-state, one-dimensional heterogeneous model. Finite element method(FEM) was applied to analyze the sensitivity of parameter and to predict the fixed-bed adsorption column performance on operation variable changes. The prediction model showed similar effect to mass transfer and intraparticle diffusion coefficient changes suggesting that both parameter present mass transfer rate limits for GAC-phenol system. The Freundlich constants had a greater effect than kinetic parameters for the performance of fixed-bed adsorption column. FEM solution facilitated prediction of concentration history in solution and within adsorbent particle.

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Breakthrough Characteristics for Lithium Ions Adsorption in Fixed-bed Column Packed with Activated Carbon by Modified with Nitric Acid (질산으로 개질한 활성탄을 충전한 고정층에서 리튬이온 흡착시의 파과특성)

  • Kam, Sang-Kyu;You, Hae-Na;Lee, Min-Gyu
    • Journal of Environmental Science International
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    • v.23 no.6
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    • pp.1143-1149
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    • 2014
  • The adsorption experiments of lithium ions were conducted in the fixed bed column packed with activated carbon modified with nitric acid. Effect of inlet concentration, bed hight and flow rate on the removal of lithium ions was investigated. The experimental results showed that the removal and the adsorption capacity of lithium ions increased with increasing inlet concentration, and decreased with increasing flow rate. When the bed height increased, the removal and the adsorption capacity increased. The breakthrough curves gave a good fit to Bohart-Adams model. Adsorption capacity and breakthrough time calculated from Bohart-Adams model, these results were remarkably consistent with the experimental values. The adsorption capacity was not changed in the case of 3 times repetitive use of adsorbent.

Quality Comparison of Activated Carbon Produced From Oil Palm Fronds by Chemical Activation Using Sodium Carbonate versus Sodium Chloride

  • MAULINA, Seri;HANDIKA, Gewa;Irvan, Irvan;ISWANTO, Apri Heri
    • Journal of the Korean Wood Science and Technology
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    • v.48 no.4
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    • pp.503-512
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    • 2020
  • Using Na2CO3 versus NaCl as chemical activator, we compared the quality of activated carbon produced from oil palm fronds as raw material. These activators were selected for comparison because both are readily available and are environmentally friendly. In the manufacturing, we used Indonesian National Standard (SNI 06-3730-1995) parameters. For the quality comparison, we determined activated-carbon yield, moisture, ash, volatiles, and fixed-carbon contents; and adsorption capacity of iodine. The best characteristics, assessed by morphological surface analysis and Fourier transform infrared (FTIR) spectral analysis, were observed in the carbon activated by Na2CO3 at an activator concentration of 10% and carbonization temperature of 400 ℃. The results were as follows: activated-carbon yield, 84%; water content, 8.80%; ash content, 2.20%; volatiles content, 14.80%; fixed-carbon content, 68.60%; and adsorption capacity of iodine, 888.51 mg/g. Identification using the FTIR spectrophotometer showed the presence of the functional groups O-H, C=O, C=C, C-C, and C-H in the Na2CO3-activated carbon.

Adsorption and Thermal Regeneration of Toluene and Benzene on the Fixed Bed Packed with Activated Carbon and Activated Carbon Fiber

  • Kim, Jong-Hwa;Oh, Ok-Kyun;Haam, Seung-Joo;Lee, Chang-Ha;Kim, Woo-Sik
    • Carbon letters
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    • v.2 no.1
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    • pp.44-54
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    • 2001
  • The characteristics of adsorption and desorption of benzene and toluene were investigated at a fixed bed packed with the activated carbon and activated carbon fiber. Through breakthrough experiments under various feed concentration conditions, it was found that the slope of mass transfer zone and the tailing in the breakthrough curves were different from the feed conditions due to different heats of adsorption. In hot nitrogen desorption, the regeneration time and mass transfer zone of the toluene desorption curve were longer than those of the benzene desorption curve because of the difference in adsorption affinity. With an increase in the regeneration temperature, the height of roll-up and the sharpness of desorption curves increased but the regeneration times decreased. The adsorption capacities of the activated carbon and activated carbon fiber after three-time thermal regenerations decreased about 25% and 37% for benzene and 18% and 25% for toluene, respectively. To investigate the effect of the regeneration temperature on the energetic efficiency, the characteristic desorption temperatures of toluene and benzene were investigated by calculating purge gas consumption and temperature.

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Numerical Study on the Ocean Sequestration of Liquid $CO_2$ (액체 이산화탄소 해양 고정화에 대한 수치적 연구)

  • Kim Nam-Jin;Chun Won-Gee;Kim Chong-Bo
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.18 no.3
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    • pp.270-278
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    • 2006
  • The idea of carbon dioxide sequestration in the ocean is proposed to be an effective mitigation strategy to counteract potential global warming due to the greenhouse effect. Therefore, in the present study, calculations of the dissolution behavior of carbon dioxide when liquid carbon dioxide is released at 1,000m and 1,500 m in depth. by fixed pipeline are peformed. The results show the liquid $CO_2$ injected in the ocean becomes $CO_2$ bubble at between 350m and 500m in depth, and the injection from a moving ship is a more effective method of dissolution than through a fixed pipeline. It so also noted that the ultimate plume generated from $CO_2$ bubbles repeats expansion and shrinking due to the peeling from a fixed pipeline.

Effect of Two-step Surface Modification of Activated Carbon on the Adsorption Characteristics of Metal Ions in Wastewater II. Dynamic Adsorption

  • Lee, Jae-Kwang;Park, Geun-Il;Ryu, Seung-Kon;Ki, Joon-Hyung
    • Carbon letters
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    • v.4 no.1
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    • pp.14-20
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    • 2003
  • Based on the previous results of the equilibrium and batch adsorptions, the removal efficiency of the two-step surface-modified activated carbon ($2^{nd}AC$) for heavy metal ions such as Pb, Cd, and Cr in fixed column was evaluated by comparing with that of the as-received activated carbon (AC) and the first surface-modified activated carbon ($1^{st}AC$). The order of metal removal efficiency was found as $2^{nd}AC$ > $1^{st}AC$ $\gg$ AC, and the efficiency of the $2^{nd}AC$ maintained over 98% from the each metal solution. Increase of the removal efficiency by the second surface modification was contributed to maintain favorable pH condition of bulk solution during adsorption process. The removal of the heavy metals on the $2^{nd}AC$ was selective with Pb being removed in preference to Cr and Cd in multicomponent solutions and slightly influenced by phenol as the organic material.

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