• Title/Summary/Keyword: Desorption gas

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A Study on Cleaning Process for Benzene Recovery in Activated Carbon Bed (활성탄을 충전한 흡착탑에서 벤젠 회수를 위한 세정공정의 연구)

  • Kang, Sung-Won;Min, Byong-Hoon;Suh, Sung-Sup
    • Journal of the Korean Applied Science and Technology
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    • v.19 no.2
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    • pp.108-116
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    • 2002
  • Experimental Study was carried out for benzene desorption by purge gas or evacuation in an activated carbon bed. As purge gas flow rate increased, desorption rate increased due to the higher interstitial linear gas velocity. For various purge gas flow rates, desoption curves almost got together if they were plotted against dimensionless time. At a higher flow rate, mass transfer zone became narrower. Temperature drop in the bed was more fast and severe at higher flow rates and higher outer temperature. It was found out that desorption was almost completed when the temperature in the drop of the bed returned to the initial temperature before temperature drop. Desorption by vacuum purge was completed in shorter time than desorption by purge gas. Countercurrent purge was more effective than cocurrent purge.

Sorbent Thermal Desorption/Gas Chromatography/Mass Selective Detection Method for Determination of Gaseous Polycyclic Aromatic Hydrocarbons in Indoor Air

  • Dai, Shugui;Zhang, Lin;Zhu, Tan
    • Analytical Science and Technology
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    • v.8 no.4
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    • pp.753-758
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    • 1995
  • Thermal desorption/gas chromatography/mass selective detection method using Tenax cartridges for the determination of gaseous polycyclic aromatic hydrocarbons(PAH) is described. Glass fiber filter can collect only PAH in particulate. Gaseous PAH may penetrate the filter. Glass cartridge packed Tenax-GC was uses fur adsorption of gaseous PAH. The air of inhalation zone was collected fur 2-10 hours. Cartridges were thermally desorbed in the reverse direction to sample flow. The desorption conditions were as follows; desorption temperature; $300^{\circ}C$; desorption time; 20min; column head pressure; 30psi; inlet split vent; closed during desorption.

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Adsorption and Desorption Dynamics of Ethane and Ethylene in Displacement Desorption Process using Faujasite Zeolite (제올라이트(faujasite)를 이용한 치환탈착공정에서 에탄, 에틸렌의 흡, 탈착 동특성)

  • Lee, Ji-In;Park, Jong-Ho;Beum, Hee-Tae;Yi, Kwang-Bok;Ko, Chang-Hyun;Park, Sung Youl;Lee, Yong-taek;Kim, Jong-Nam
    • Korean Chemical Engineering Research
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    • v.48 no.6
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    • pp.768-775
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    • 2010
  • Adsorption dynamics of ethane/ethylene mixture gas and desorption dynamics during the displacement desorption with propane as a desorbent in the column filled with faujasite adsorbent were investigated experimentally and theoretically. The simulation that adopted heat and mass balance and an ideal adsorbed solution theory (IAST) for the multicomponent adsorption equilibrium well predicted the experimental breakthrough curves of the adsorption and desorption. At the adsorption breakthrough experiments, roll-ups of ethane increased as the adsorption pressure increased and the adsorption temperature decreased. During the displacement desorption with propane in the column saturated with ethane/ethylene mixture gas, almost 100% of ethylene was obtained for a certain time interval. The adsorption strength of the desorbent greatly affected the adsorption and re-adsorption dynamics of ethylene. The re-adsorption capacity for ethylene has been greatly reduced when iso-propane, which is stronger desorbent than propane, was used as desorbent. It was found from the simulation that the performance of the displacement desorption process would be superior when the ratio of ${(q_s{\times}b)}_{C_2H_4}/{(q_s{\times}b)}_{C_3H_s}$ was 0.83, that is, the adsorption strengths of ethylene and the desorbent were similar.

Manufacture of the Hydrophobic HY-type Zeolite-honeycomb and Its Adsorption/Desorption Characteristics for the Benzene, o-xylene, and MEK (소수성 HY-형 제올라이트제 하니컴의 제조 및 그 하니컴의 벤젠, o-xylene, MEK에 대한 흡.탈착특성)

  • Mo, Se-Young;Jeon, Dong-Hwan;Kwon, Ki-Seung;Sohn, Jong-Ryeul
    • Journal of Korean Society for Atmospheric Environment
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    • v.23 no.1
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    • pp.84-96
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    • 2007
  • We performed the experiments to manufacture the hydrophobic $200cells/in^2$-zeolite honeycomb using HY-type zeolite of Si/Al ratio of 80 for separating and removing the VOCs emitted from small and medium size-plants by adsorption and to determine the drying method for the honeycomb at $105^{\circ}C$ without cracking, then measured performances of the honeycomb to adsorb the benzene, o-xylene, and MEK and to desorb the benzene and MEK saturated on the honeycomb by the nitrogen gas as the desorption gas. As a results, the good honeycomb was formed and the honeycomb was not cracked when the mixing ratio of the zeolite to bentonite to methyl cellulose to polyvinyl alcohol to glycerine to water is 100 : 8.73 : 2.18 : 4.19 : 1.38 : 126 and dried the honeycomb at $105^{\circ}C$ for 24 hours in the drying oven. The shape of the dried honeycomb was not changed after calcination, and the compressive strengths of the honeycomb after drying and calcination were 6.7 and $0.69kg/cm^2$, respectively. The adsorption efficiencies of the honeycomb for benzene, o-xylene, and MEK were $92{\sim}96%$ at the room temperature. The desorption efficiency at $180^{\circ}C$ was higher than that at $150^{\circ}C\;by\;1.5{\sim}13.8%$ depending on the flow rate of the nitrogen gas, and it was found that desorption efficiency is higher than 85% at $180^{\circ}C$ and 1.0L/min of the nitrogen gas. At $180^{\circ}C$ and 0.2 L/min, the concentration of the benzene and MEK in the used desorption gas are higher than 40,000 and 50,000ppm, respectively, so it be used as the fuel for preheating the desorption gas fed into the column in desorption cycle.

Heat Energy Diffusion Analysis in the Gas Sensor Body with the Variation of Drain-Source Electrode Distance (드레인-소스 전극 간극의 변화에 따른 Gas Sensor의 열에너지 확산 해석)

  • Jang, Kyung-Uk
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.30 no.9
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    • pp.589-595
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    • 2017
  • MOS-FET structured gas sensors were manufactured using MWCNTs for application as NOx gas sensors. As the gas sensors need to be heated to facilitate desorption of the gas molecules, heat dispersion plays a key role in boosting the degree of uniformity of molecular desorption. We report the desorption of gas molecules from the sensor at $150^{\circ}C$ for different sensor electrode gaps (30, 60, and $90{\mu}m$). The COMSOL analysis program was used to verify the process of heat dispersion. For heat analysis, structure of FET gas sensor modeling was proceeded. In addition, a property value of the material was used for two-dimensional modeling. To ascertain the degree of heat dispersion by FEM, the governing equations were presented as partial differential equations. The heat analysis revealed that although a large electrode gap is advantageous for effective gas adsorption, consideration of the heat dispersion gradient indicated that the optimal electrode gap for the sensor is $60{\mu}m$.

Composition and Evaluation of the Thermal Desorption-Gas Chromatographic System for the Measurement of Volatile Organic Compounds in Air (공기 중 휘발성 유기화합물의 측정을 위한 열탈착-분석시스템의 구성 및 평가)

  • 이수형;송희남;김희갑
    • Environmental Analysis Health and Toxicology
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    • v.17 no.1
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    • pp.63-71
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    • 2002
  • The thermal desorption-gas chromatographic (TD-GC) system has been constructed for the measurement of volatile organic compounds. The thermal desortion unit is composed of four major parts: 1) the control part; 2) the thermal desorption part; 3) the focusing part; and 4) the injection part. The peltier element was introduced to the focusing part for the temperature of the focusing tube to reach-35$^{\circ}C$. The system was tested for the linearity of the calibration curves and reproducibility of instrumental analyses using some disinfection by-products (DBPs) and BTXs (benzene, toluene and p-xylene). The coefficients of determination (r$^2$) for all the calibration curves made were higher than 0.998, and the coefficients of variation (CV) for triplicate measurements were all within 10%. The system also has been tested for field applicability. The analysis of field samples showed that there was no breakthrough problem in the sampling system and that the system could be applied to field measurements.

Characteristics of Desorption for Benzene in Activated Carbon and Zeolite 13X Packed Bed (벤젠에 대한 활성탄 및 제올라이트 13X를 충진한 흡착탑에서 탈착 특성)

  • Kang, Sung-Won;Suh, Sung-Sup;Min, Byung-Hoon
    • Applied Chemistry for Engineering
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    • v.17 no.2
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    • pp.201-209
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    • 2006
  • Various desorption methods were investigated for an activated carbon and zeolite 13X packed bed after benzene adsorption. Desorption experiments using hot steam, purge gas, and evacuation were performed. As a result, the desorption with hot steam showed the best performance. Hot steam makes the temperature in the adsorption column increase and gives arise to the desorption. Drying process should be accompanied to increase the efficiency because steam vapor prevents the adsorption later. The vacuum desorption showed poor performance and it reveals that temperature swing operation is more effective than pressure swing operation. In the purge gas desorption, good performance was achieved using evacuation.

The Study of Crude Oil Contaminated Soil Remediation by Indirect Thermal Desorption (간접열탈착방식을 이용한 원유오염토양 정화효율 평가)

  • Lee, In;Kim, Jong-Sung;Jung, Tae-Yang;Oh, Seung-Taek;Kim, Guk-Jin
    • Journal of Soil and Groundwater Environment
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    • v.21 no.3
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    • pp.14-20
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    • 2016
  • Remediation of crude oil contaminated soil is complicate and hard to apply traditional methods because of its persistency, durability, and high viscosity. Therefore, in this study, the efficiency of crude oil contaminated soil remediation was tested by developing a pilot-scale thermal desorption system using the indirect heating method with an exhaust gas treatment. Under optimal condition drawed by temperature and retention time, the remedial efficiency of crude oil contaminated soil and treatability of exhaust gas were analyzed. Total Petroleum Hydrocarbon (TPH) concentration of crude oil contaminated soil was decreased to 69.7 mg/kg on average and the remedial efficiency was measured at 99.60%. Through the exhaust gas, 86.0% of Volatile Organic Compounds (VOC) was degraded and 97.16% of complex malodor was reduced under the suggested optimum operation condition. This study provides important basic data to be useful in scaling up of the indirect thermal desorption system for the remediation of crude oil contaminated soil.

Characteristics of Low Temperature Desorption of Volatile Organic Compounds from Waste Activated Carbon in Cylindrical Cartridge (원통형 활성탄 카트리지 내 폐활성탄의 휘발성 유기화합물 저온 탈착 특성)

  • Kang, Sin-Wook;Lee, Seongwoo;Son, Doojeong;Han, Moonjo;Lee, Tae Ho;Hong, Sungoh
    • Clean Technology
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    • v.27 no.1
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    • pp.79-84
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    • 2021
  • In this study, the waste activated carbon used in the painting process was filled into a cylindrical cartridge and the characteristics of desorption by low temperature gas were investigated. Adsorption and desorption experiments of toluene with activated carbon were conducted to determine the flow rate of desorption. In an experiment where desorption was performed while changing conditions at flow rates of 1, 2 and 4 ㎥ min-1, it was determined that 2 ㎥ min-1 was appropriate due to the high THC concentration and desorption time. In the early stage of the desorption of waste activated carbon, 2-butanone and MIBK (methyl isobutyl ketone) with a low boiling point were generated at a high rate in the gas component, and after that, the concentration of THC decreased and the BTX was desorbed at a high rate. The total calorific value of the gas component generated during the desorption of waste activated carbon was 316 kcal kg-1. From repeating the regeneration of waste activated carbon with toluene five times, it was observed that the iodine value and the specific surface area were relatively lower than that of new activated carbon. In the desorption experiment where two cylindrical cartridges were connected in series, the maximum THC concentration was about 470 ppm.

Catalyst-aided Regeneration of Amine Solvents for Efficient CO2 Capture Process

  • Bhatti, Umair H.;Sultan, Haider;Cho, Jin Soo;Nam, Sungchan;Park, Sung Youl;Baek, Il Hyun
    • Journal of Energy Engineering
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    • v.28 no.4
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    • pp.8-12
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    • 2019
  • Thermal amine scrubbing is the most advanced CO2 capture technique but its largescale application is hindered due to the large heat requirement during solvent regeneration step. The addition of a solid metal oxide catalysts can optimize the CO2 desorption rate and thus minimize the energy consumption. Herein, we evaluate the solvent regeneration performance of Monoethanolamine (MEA) and Diethanolamine (DEA) solvents without and with two metal oxide catalysts (TiO2 and V2O5) within a temperature range of 40-86℃. The solvent regeneration performance was evaluated in terms of CO2 desorption rate and overall amount of CO2 desorbed during the experiments. Both catalysts improved the solvent regeneration performance by desorbing greater amounts of CO2 with higher CO2 desorption rates at low temperature. Improvements of 86% and 50% in the CO2 desorption rate were made by the catalysts for MEA and DEA solvents, respectively. The total amount of the desorbed CO2 also improved by 17% and 13% from MEA and DEA solvents, respectively. The metal oxide catalyst-aided regeneration of amine solutions can be a new approach to minimize the heat requirement during solvent regeneration and thus can remove a primary shortfall of this technology.