• Title/Summary/Keyword: Low temperature desorption

Search Result 130, Processing Time 0.029 seconds

A Study on the Performance Prediction of Low Temperature Thermal Desorption System (저온 수처리장치 열교환기의 열전달 특성에 관한 연구)

  • Lee, C.T.
    • Journal of Power System Engineering
    • /
    • v.13 no.6
    • /
    • pp.76-81
    • /
    • 2009
  • Thermal desorption systems are designed to remove organic compounds from solid matrices such as soils, sludges and filter cakes without thermally destroying them. It is a separation technology, not a destruction technology. Since it is a thermal process, there is a common belief that temperature is the only significant parameter to be monitored. While it is true that better removal efficiencies are usually achieved at higher temperatures, other factors must be considered. Since the process is governed by mass transfer, heating time and the amount of mixing are also key parameters in optimizing removal efficiency. Thermal desorption have been successfully used for just about every organic contaminant found to date. It has also been used to remove mercury. In the present study, the numerical simulation has been performed to investigate the characteristics of heat transfer of LTTD(low temperature thermal desorption). The commercial software, AMESIM was applied for analyzing the heat transfer process in the LTTD.

  • PDF

Effect of Temperature, Pressure, and Air Flow Rate on VOCs Desorption for Gasoline Vapor Recovery (유증기 회수를 위한 VOCs 탈착에 미치는 온도, 압력 및 공기유량의 영향)

  • Lee, Song-Woo;Na, Young-Soo;Kam, Sang-Kyu;Lee, Min-Gyu
    • Journal of Environmental Science International
    • /
    • v.22 no.9
    • /
    • pp.1131-1139
    • /
    • 2013
  • Desorption characteristics of VOCs were investigated for the effective recovery of gasoline vapor. The adsorption capacity and desorption capacity were excellent at relatively low temperatures. The differences in the desorption capacity were not large in the condition; desorption temperature $25^{\circ}C$, desorption pressure 760 mmHg, inlet air flow rate 0.5 L/min, but were relatively great in the condition; desorption temperature $0^{\circ}C$, desorption pressure 60 mmHg, inlet air flow rate 1.0 L/min. The desorption ability of pentane was increased to about 81.4%, and the desorption ability of hexane was increased to about 102%, also the desorption ability of toluene was increased to about 156.7% by changes of temperature, pressure, inlet air flow rate in the experimental conditions. The optimum desorption condition for the effective recovery of VOCs was in the conditions; desorption temperature $0^{\circ}C$, desorption pressure 60 mmHg, inlet air flow rate 1.0 L/min.

The Interaction of Hydrogen Atom with ZnO: A Comparative Study of Two Polar Surfaces

  • Doh, Won-Hui;Roy, Probir Chandra;Kim, Chang-Min
    • Proceedings of the Korean Vacuum Society Conference
    • /
    • 2012.02a
    • /
    • pp.249-249
    • /
    • 2012
  • The interaction of hydrogen with ZnO single crystal surfaces, ZnO(0001) and ZnO(000-1), has been investigated using a temperature programmed desorption (TPD) technique. Both surfaces do not interact with molecular hydrogen. When the ZnO(0001) is exposed to atomic hydrogen at 370 K, hydrogen is adsorbed in the surface and desorption takes place at around 460 K and 700 K. In ZnO(000-1), the desorption peaks are observed at around 440 K and 540 K. In both surfaces, as the atomic hydrogen exposure is further increased, the intensity of the low-temperature peak reaches maximum but the intensity of the high-temperature peak keeps increasing. In ZnO(000-1), the existence of hydrogen bonding to the surface O atoms and the bulk hydrogen has been confirmed by using X-ray photoelectron spectroscopy (XPS). When the Zn(0001) surface is exposed to atomic hydrogen at around 200 K, a new $H_2$ desorption peak has been observed at around 250 K. The intensity of the desorption feature at 250 K is much greater than that of the desorption feature at 460 K. This low-temperature desorption feature indicates hydrogen is bonded to surface Zn atoms. We will report the effect of the ZnO structure on the adsorption and bulk diffusion of hydrogen.

  • PDF

Adsorption of Atomic Hydrogen on ZnO Single Crystal Surfaces: A Study on the Impact of Surface Structure

  • Roy, Probir Chandra;Motin, Abdul;Kim, Chang-Min
    • Proceedings of the Korean Vacuum Society Conference
    • /
    • 2012.08a
    • /
    • pp.216-216
    • /
    • 2012
  • The interaction of hydrogen with ZnO single crystal surfaces, ZnO (0001), ZnO (000-1), and ZnO (10-10) has been investigated using temperature programmed desorption (TPD) and X-ray photoelectron Spectroscopy (XPS) techniques. When the ZnO single crystal surfaces are exposed to atomic hydrogen at 200 K, all three surfaces show hydrogen desorption at 450 K. ZnO (0001) surface shows hydrogen desorption feature at ~260 K as the hydrogen exposure is increased. The ZnO (10-10) surface shows low-temperature desorption feature first and the high-temperature desorption feature appears as the hydrogen exposure increases. The ZnO (000-1) surface does not show any lower temperature hydrogen desorption. We will report the adsorption configuration of hydrogen atoms on ZnO single crystal surfaces with different surfaces structures.

  • PDF

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
    • /
    • v.27 no.1
    • /
    • pp.79-84
    • /
    • 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.

Modeling of Absorption/Desorption of Fuel in Oil film on the Cylinder Liner in SI Engines (오일유막의 연료 흡수 및 방출에 관한 연구)

  • 유상석;민경덕
    • Transactions of the Korean Society of Automotive Engineers
    • /
    • v.7 no.9
    • /
    • pp.165-171
    • /
    • 1999
  • An oil layer fuel absorption /desorption modeling was developed. Multi-component fuel model has showed more reasonable condition than single component model. Henry's constant which is related to solubility is the most important variable in the oil layer absorption/desorption mechanism. The oil segments close to the top of the cylinder liner have more significant contribution to the fuel absorption and desorption process than other oil segments. At the warmed-up condition, the effect of the engine speed on the precent fuel absorbed/desorbed is minimal. But at low il film temperature, percent of fuel abosrbed/desorbed is decreased with increasing the engine speed because of low value of molecular diffusion coefficient of fuel. The amount of fuel trapped in the piston crevice is from 2 to 2.3 times larger than that of fuel in the oil fim. However, fuel form oil film slowly desorbs into the combustion chamber compared with fuel from the piston crevices when the engines is cold.

  • PDF

Adsorption and Desorption Characteristics of Carbon Dioxide at Low Concentration on Zeolite 5A and 13X (제올라이트 5A와 13X의 저농도 이산화탄소 흡착 및 탈착특성)

  • Cho, Young-Min;Lee, Ji-Yun;Kwon, Soon-Bark;Park, Duck-Shin;Choi, Jin-Sik;Lee, Ju-Yeol
    • Journal of Korean Society for Atmospheric Environment
    • /
    • v.27 no.2
    • /
    • pp.191-200
    • /
    • 2011
  • A way to adsorptively remove indoor carbon dioxide at relatively lower concentration under ambient temperature was studied. A small lab-scale carbon dioxide adsorption and desorption reactors were prepared, and 5A and 13X zeolites were packed in this reactors to investigate their adsorption and desorption characteristics. The inflow carbon dioxide concentration was controlled to 5,000 ppm, relatively higher concentration found in indoor spaces with air quality problems, by diluting carbon dioxide with nitrogen gas. The flow rate was varied as 1~5 L/min, and the carbon dioxide concentration after this reactor was constantly monitored to examine the adsorption characteristics. It was found that 5A adsorbed more carbon dioxide than 13X. A lab-scale carbon dioxide desorption reactor was also prepared to investigate the desorption characteristics of zeolites, which is essential for the regeneration of used zeolites. The desorption temperature was varied as $25{\sim}200^{\circ}C$, and the desorption pressure was varied as 0.1~1.0 bar. Carbon dioxide desorbed better at higher temperature, and lower pressure. 5A could be regenerated more than three times by thermal desorption at $180^{\circ}C$. It is required to modify zeolites for higher adsorption and better regeneration performances.

Effect of Low Temperature Plasma and DCCA treatment on the Dyeing Properties of Wool Fabric (DCCA 처리와 저온플라즈마 처리가 양모직물의 염색성에 미치는 영향)

  • Jung, Young-Jin
    • Textile Coloration and Finishing
    • /
    • v.20 no.4
    • /
    • pp.53-59
    • /
    • 2008
  • For the modification of wool surface, wool fabrics treated with oxygen low-temperature plasma(LTP) and dichloroisocyanuric acid(DCCA) were dyed with milling type acid dye. The difference of dyeing properties on modified and control wool fabric were investigated. DCCA treated wool showed that saturation dye uptake and dyeing desorption ratio were higher than LTP treated wool. Dyeing transition temperatures of DCCA and LTP treated wool fabrics were 20$^{\circ}C$ degree lower than control wool fabric. In light color fastness test, DCCA treated wool fabric was 1 grade lower than LTP or control wool fabric.

Optical Transmittance Change of Pd Thin Film by Hydrogen Absorption and Desorption (수소 흡수-방출에 의한 Pd 박막의 광투과도 특성변화)

  • Cho, Young sin
    • Transactions of the Korean hydrogen and new energy society
    • /
    • v.12 no.4
    • /
    • pp.287-292
    • /
    • 2001
  • The optical transmittance change of Pd thin film due to hydrogen absorption and desorption was examined at room temperature. Hydrogen absorption and desorption cycling effects on optical transmittance were measured 6 times in the pressure range between 0 and 640 torr. Optical transmittance of Pd film was increasing with increasing hydrogen pressure. Ratio of optical transmittance to the change of pressure at $\beta$ phase is bigger than that of low hydrogen pressure range.

  • PDF

Adsorption of Amine and Sulfur Compounds by Iron Phthalocyanine Derivatives (철 프탈로시아닌 유도체에 의한 아민 및 황 화합물의 흡착)

  • Lee, Jeong-Se;Park, Jin-Do;Lee, Hak-Sung
    • Journal of Korean Society for Atmospheric Environment
    • /
    • v.23 no.5
    • /
    • pp.575-584
    • /
    • 2007
  • The adsorption capability of iron phthalocyanine derivatives were investigated by means of X-ray diffractometor (XRD), IR (infrared) spectroscopy, scanning electron microscopy (SEM) and temperature programmed desorption (TPD). According to TPD results, iron phthalocyanine derivatives showed two desorption peaks at low temperature ($100{\sim}150^{\circ}C$) and high temperature ($350{\sim}400^{\circ}C$) indicating that there were two kinds of acidities. Tetracarboxylic iron phthalocyanine (Fe-TCPC) have a stronger desorption peak (chemical adsorption) at the high temperature and a weaker desorption peak (physical adsorption) at the low temperature than iron phthalocyanine (Fe-PC). The specific surface areas of Fe-TCPC and Fe-PC were $26.46\;m^2/g\;and\;11.77\;m^2/g$, respectively. The pore volumes of Fe-TCPC and Fe-PC were $0.14\;cm^3/g\;and\;0.06\;cm^3/g$, respectively. The adsorption capability of triethyl amine calculated by breakthrough curve at 220 ppm of equilibrium concentration was 29.2 mmoL/g for Fe-TCPC and 0.8 mmoL/g for Fe-PC. The removal efficiency of dimethyl sulfide of Fe-TCPC and Fe-PC in batch experiment of 225 ppm of initial concentration were 44.9% and 28.9%, respectively. The removal efficiency of trimethyl amine of Fe-TCPC and Fe-PC in batch experiment of 118 ppm of initial concentration were approximately 100.0% and 33.9%, respectively.