• Title/Summary/Keyword: Tetrafluoromethane

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The Investigation of CF4 Decomposition in Methane Premixed Flames on Oxygen Enrichment (산소부화된 메탄 예혼합 화염에서 CF4 분해에 대한 연구)

  • Lee, Ki Yong
    • Journal of the Korean Society of Combustion
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    • v.22 no.4
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    • pp.51-56
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    • 2017
  • The decomposition of tetrafluoromethane has been investigated with the reaction mechanism proposed for freely propagating $CH_4/CF_4/O_2/N_2$ premixed flames on the oxygen enrichment. The factors affecting on the removal efficiency of tetrafluoromethane were analyzed. The increase in flame temperature due to oxygen enrichment has a great influence on the removal efficiency of tetrafluoromethane. At the same oxygen enrichment condition, the removal efficiency in the rich flame is higher than one in the lean flame. The increase of the F/H ratio leads to decrease the flame temperature and the removal efficiency of tetrafluoromethan is decreased at the flame temperature of 2600 K or lower, The elementary reactions that dominate the consumption of tetrafluoromethane are (R1) $CF_4+M=CF_3+F+M$ and (R2) $CF_4+H=CF_3+HF$. (R1) has the greatest effect on the consumption of tetrafluoromethane under the oxygen enhanced flames.

Decomposition Characteristics of Tetrafluoromethane Using a Waterjet Plasma Scrubber (워터젯 플라즈마 스크러버 사불화탄소 분해 특성)

  • Lim, Mun Sup;Chun, Young Nam
    • Journal of Climate Change Research
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    • v.8 no.1
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    • pp.63-71
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    • 2017
  • It is recognized that tetrafluoromethane ($CF_4$) has a great influence on global warming. The $CF_4$ is known to have a large impact on climate change due to its large global warming index. In this study, a waterjet plasma scrubber (WPS) was designed and manufactured for the $CF_4$ decomposition. The WPS is a novel technology which is combined a gliding arc plasma and water injection at the center of the plasma discharge. This can give an innovative way for $CF_4$ decomposition by achieving larger plasma columnand generating OH radicals. A performance analysis was achieved for the design factors such as waterjet flow rate, total gas flow rate, consumption electric power, and electrode gap. The highest $CF_4$ decomposition and energy efficiencies were 64.8% and 6.43 g/kWh, respectively; Optimal operating conditions were 20 mL/min of waterjet flow rate, 200 L/min total gas flow rate, 5.3 kW consumption electric power, and 4.4 mm electrode gap. As for the 2 stage reactor of the WPS, the $CF_4$ decomposition efficiency improved as the 85.3% while the energy efficiency decreased as the 5.57 g/kWh.

CHARACTERIXATION OF PLASMA ION IMPLANTED SURFACES USING TIME-OF-FLIGHT SECONDARY ION MASS SPECTROMATRY

  • Lee, Yeon-Hee;Han, Seung-Hee;Lee, Jung-Hye;Yoon, Jung-Hyeon
    • Journal of the Korean institute of surface engineering
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    • v.29 no.6
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    • pp.880-883
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    • 1996
  • Plasma Source Ion Implantation (PSII) technique was used for the hydrophilization or hydrophobization of polymer surfaces. Polymers were modified with different plasma gases such as oxygen, nitrogen, argon, and tetrafluoromethane, and for varying lengths of treatment time. Plasma ion treatment of oxygen, nitrogen, argon and their mixtures increased significantly the hydrophilic properties of polymer surfaces. More hydrophobic surfaces of polymers were formed after the treatment with tetrafluoromethane. A study of plasma source ion implanted polymers was performed using contact angle measurements and Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS). The TOF-SIMS spectra and depth profile were used to obtain the information about the treated surfaces of polymers. The permanence of this technique could be evaluated with respect to ageing time. The surfaces treated with PSII gave better stability than other surface modification methods.

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Reduction of Tetrafluoromethane using a Waterjet Gliding Arc Plasma (워터젯 글라이딩 아크 플라즈마를 이용한 사불화탄소 저감)

  • Lee, Chae Hong;Chun, Young Nam
    • Korean Chemical Engineering Research
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    • v.49 no.4
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    • pp.485-490
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    • 2011
  • Tetrafluoromethane($CF_4$) has been used as etching and chamber cleaning gases for semiconductor manufacturing processes. These gases need to be removed efficiently because of their strong absorption of infrared radiation and long atmospheric lifetime which causes the global warming effect. We have developed a waterjet gliding arc plasma system in which plasma is combined with waterjet and investigated optimum operating conditions for efficient $CF_4$ destruction through enlarging discharge region and producing large amount of OH radicals. The operating conditions are waterjet flow rate, initial $CF_4$ concentration, total gas flow rate, specific energy input. Through the parametric studies, the highest $CF_4$ destruction of 97% was achieved at 2.2% $CF_4$, 7.2 kJ/L SEI, 9 L/min total gas flow rate and 25.5 mL/min waterjet flow rate.

Improving CO2 Adsorption Performance of Activated Carbons Treated by Plasma Reaction with Tetrafluoromethane (사불화탄소 플라즈마 반응에 의해 처리된 활성탄소의 CO2 흡착 성능 향상)

  • Chung Gi Min;Chaehun Lim;Seo Gyeong Jeong;Seongjae Myeong;Young-Seak Lee
    • Applied Chemistry for Engineering
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    • v.34 no.2
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    • pp.170-174
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    • 2023
  • CO2 is known as one of the causes of global warming, and various studies are being conducted to capture it. In this study, a tetrafluoromethane (CF4) plasma reaction was performed to improve the CO2 adsorption of activated carbons (ACs) through changes in surface characteristics, and the adsorption characteristics according to the reaction time were considered. After the reaction, the micropore volume increased up to 1.03 cm3/g. In addition, as the reaction time increased, the fluorine content on the surface increased to 0.88%. It was possible to simultaneously control the pore properties and surface functional groups of the ACs through this experiment. Also, the CO2 uptake of surface-treated ACs improved up to 7.44% compared to untreated ACs, showing the best performance at 3.90 mmol/g when the reaction time was 60 s. This is due to the synergy effect of the fluorine functional groups introduced on the surface of the ACs and the increased micropore volume caused by the etching effect. It was found that the micropore volume had a greater effect on CO2 adsorption in the region where the CO2 uptake was less than 3.67 mmol/g, while the added fluorine content had a greater effect in the region above that.

Removal of Hydrogen Fluoride from Waterjet Plasma Wastewater by Electrocoagulation (전해응집법에 의한 불화수소 함유 워터젯 플라즈마 폐수처리)

  • Lee, Chae Hong;Chun, Young Nam
    • Journal of Korean Society of Environmental Engineers
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    • v.34 no.10
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    • pp.702-708
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    • 2012
  • Tetrafluoromethane ($CF_4$) has been used as etching and Chemical Vapor Deposition (CVD) gases for semiconductor manufacturing processes. These gases need to be removed efficiently because of their strong absorption of infrared radiation and long atmospheric lifetimes which cause the global warming effect. Also, the wastewater including the fluorine is caused by of the ground water pollution. Long-term consumption of water containing excessive fluoride can lead to fluorosis of the teeth and bones. The wastewater including the fluorine among the by-product which is generated by using the waterjet plasma after destroying $CF_4$ by HF is generated. The system which can remove the hydrogen fluoride among the wastewater by using the electrocoagulation using this wastewater the aluminum electrode was developed. The operating condition such as initial pH, electrocoagulation time, wastewater flow rate, current density were investigated experimentally using a electrocoagulation. Through the parametric studies, the highest hydrogen fluoride destruction of 85% was achieved at 3.5 initial pH, 10 min electrocoagulation time, 10 mL/min wastewater flow rate and $159A/m^2$ current density.

Decomposition Characteristics of PFCs for Various Plasma Discharge Methods in Dielectric Barrier Discharge (DBD 반응기에서 플라즈마 방전형태에 따른 PFCs 가스의 분해 특성)

  • Kim, Kwan-Tae;Kim, Yong-Ho;Cha, Min-Suk;Song, Young-Hoon;Kim, Seock-Joon;Ryu, Jeong-In
    • Journal of Korean Society for Atmospheric Environment
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    • v.20 no.5
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    • pp.625-632
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    • 2004
  • Perfluorocompounds ($PFC_s$), such as tetrafluoromethane ($CF_4$) and hexafluoroethane ($C_2F_6$), have been widely used as plasma etching and chemical vapor deposition (CVD) gases for semiconductor manufacturing processes. Since these $PFC_s$ are known to cause a greenhouse effect intensively, there has been a growing interest in reducing $PFC_s$ emissions. Among various $CF_4$ decomposing techniques, a dielectric barrier discharge (DBD) is considered as one of a promising candidate because it has been successfully used for generating ozone ($O_3$) and decomposing nitrogen oxide (NO). Firstly, optimal concentration of oxygen for $CF_4$ decomposition was found to figure out how many primary and secondary reactions are associated with DBD process. Secondary, to find effective discharge method for $CF_4$ decomposition, a streamer and a glow mode in DBD are experimentally compared, which includes (i) coaxialcylinder DBD, (ii) DBD reactor packed with glass beads. and (iii) a glow mode operation with a helium gas. The test results showed that optimal concentration of oxygen was ranged 500 ppm~1% for treating 500 ppm of $CF_4$ and helium glow discharge was the most efficient one to decompose $CF_4$.

Effects of Operating Parameters on Tetrafluoromethane Destruction by a Waterjet Gliding Arc Plasma (워터젯 글라이딩 아크 플라즈마에 의한 사불화탄소 제거에 미치는 운전변수의 영향)

  • Lee, Chae Hong;Chun, Young Nam
    • Applied Chemistry for Engineering
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    • v.22 no.1
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    • pp.31-36
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    • 2011
  • Tetrafluoromethane ($CF_4$) has been used as the plasma etching and chemical vapor deposition (CVD) gas for semiconductor manufacturing processes. However, the gas need to be removed efficiently because of their strong absorption of infrared radiation and the long atmospheric lifetime which cause global warming effects. A waterjet gliding arc plasma system in which plasma is combined with the waterjet was developed to effectively produce OH radicals, resulting in efficient destruction of $CF_4$ gas. Design factors such as electrode shape, electrode angle, gas nozzle diameter, electrode gap, and electrode length were investigated. The highest $CF_4$ destruction of 93.4% was achieved at Arc 1 electrode shape, $20^{\circ}$ electrode angle, 3 mm gas nozzle diameter, 3 mm electrode gap and 120 mm electrode length.

CF4 Treatment Characteristics using an Elongated Arc Reactor (신장 아크 반응기를 이용한 CF4 처리특성)

  • Kim, Kwan-Tae;Lee, Dae-Hoon;Lee, Jae-Ok;Cha, Min-Suk;Song, Young-Hoon
    • Journal of Korean Society for Atmospheric Environment
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    • v.26 no.1
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    • pp.85-93
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    • 2010
  • $CF_4$ removal characteristics were investigated using an elongated arc reactor. The advantage of the elongated arc reactor includes direct use of treated gas as plasma operating gas and the enhancement of the removal reaction by using a thermo-chemistry and a plasma induced chemistry at the same time. Geometrical configurations, such as the length of the reactor and the shape of a throat, were tested to get an optimized removal efficiency with low power consumption. As results, over 95% of $CF_4$ removal was obtained with 300 lpm of total flowrate for various $CF_4$ concentration (0.1~1%). Corresponding specific energy density (SED), which means required electrical energy to treat the unit volume of treated gas, is about 3.5 kJ/L, The present technique can be applied to real applications by satisfying three major concerns, those are the high flowrate of treated gas, high removal efficiency (> 95%), and low power consumption (< 10 kJ/L).

Microwave Thermal Decomposition of CF4 using SiC-Al2O3 (SiC-Al2O3 촉매를 이용한 CF4의 마이크로파 열분해)

  • Choi, Sung-Woo
    • Journal of Environmental Science International
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    • v.22 no.9
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    • pp.1097-1103
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    • 2013
  • Tetrafluoromethane($CF_4$) have been widely used as etching and chemical vapor deposition gases for semiconductor manufacturing processes. $CF_4$ decomposition efficiency using microwave system was carried out as a function of the microwave power, the reaction temperature, and the quantity of $Al_2O_3$ addition. High reaction temperature and addition of $Al_2O_3$ increased the $CF_4$ removal efficiencies and the $CO_2/CF_4$ ratio. When the SA30 (SiC+30wt%$Al_2O_3$) and SA50 (SiC+50wt%$Al_2O_3$) were used, complete $CF_4$ removal was achieved at $1000^{\circ}C$. The $CF_4$ was reacted with $Al_2O_3$ and by-products such as $CO_2/CF_4$ and $AlF_3$ were produced. Significant amount of by-product such as $AlF_3$ was identified by X-ray powder diffraction analysis. It also showed that the ${\gamma}-Al_2O_3$ was transformed to ${\alpha}-Al_2O_3$ after microwave thermal reaction.