공정 온도에 따른 사면체 비정질 카본 (ta-C) 코팅의트라이볼로지적 특성연구

강용진,김도현,김종국,장영준,류호준 한국트라이볼로지학회 2019 한국윤활학회지(윤활학회지) Vol.35 No.6

In this study, mechanical and tribological properties were investigated by varying the process temperature (50, 100, 125 and 150 oC) to reduce internal stress. The internal stress reduction by thermal dissociation ta-C coating film with increasing temperature is confirmed through the curvature radius of the ta-C coating according to the temperature of the SUS plate. As the coating temperature increased, the mechanical properties (hardness, modulus, toughness) deteriorated, which is in agreement with the Raman analysis results. As the temperature increased, the sp2 phase ratio increased owing to the dissociation of the sp3 phase. The friction and wear properties are related to the process temperature during ta-C coating. Low friction and wear properties are observed in high hardness samples manufactured at 50 oC, and wear resistance properties decreased with increasing temperature. The contact area is expected to increase owing to the decrease of hardness(72 GPa to 39 GPa) and fracture toughness with increasing temperature which accelerated wear because of the debris generated. It was confirmed that at process temperature of over than 100 oC, the bond structure of the carbon film changed, and the effect of excellent internal stress was reduced. However, the wear resistance simultaneously decreased owing to the reduction in fracture toughness. Therefore, in order to increase industrial utilization, optimum temperature conditions that reduce internal stress and retain mechanical properties.

미량오염물질 제거능 향상을 위한 생물활성탄 공정의 강화

손희종,정은영,염훈식,최상기,박홍기 대한환경공학회 2023 대한환경공학회지 Vol.45 No.12

목적 : 본 연구에서는 생물막 특성이 강화된 BAC 공정에서의 미량오염물질의 제거효율을 일반 BAC 공정과 비교·평가하여, 정수장의 BAC 공정에서 미량오염물질의 제거효율을 상승시킬 수 있는 방안을 제시하고자 하였다. 방법 : 대상 미량오염물질로는 dibromo-methylparaben (Br2-MP)를 선정하였다. 회분식 실험과 실험실 규모 컬럼 실험을 수행하여 일반 BAC 공정과 인(P) 및 과산화수소(H2O2)를 첨가하여 생물막 특성을 강화한 BAC에서 Br2-MP의 제거 효율을 평가하였다. 회분식 및 실험실 규모의 컬럼 실험 결과를 사용하여 생분해 동역학을 평가하였다. 결과 및 토의 : 동일한 생체량 조건(2.0±0.2×107 cells)에서 Br2-MP의 제거효율을 비교한 회분식 실험에서 생물학적 활성도가 높게 나타난 강화 BAC 공정의 생물분해 속도상수(kbio)는 일반 BAC 공정보다 1.2배 높았다(강화 BAC: 3.4±0.3 mg·C/g·hr, 일반 BAC: 2.9±0.4 mg·C/g·hr). 동일한 습중량(1 g) 조건으로 Br2-MP의 제거효율을 비교한 회분식 실험에서, 생체량 함량이 높은 강화 BAC 공정의 생물분해 속도상수(kbio)는 일반 BAC 공정보다 1.9배 더 높았다(강화 BAC: 3.5±0.4 µg·ATP/g·GAC, 일반 BAC: 2.3±0.2 µg·ATP/g·GAC). 회분식 실험을 통해 강화 BAC 공정은 부착된 박테리아의 생체량과 활성이 증가하여 Br2-MP 제거에 더 효율적이었다. 다양한 수온(5, 25℃)과 공탑 체류시간(EBCT: 5-40분) 조건에서 실험실 규모의 컬럼 실험을 진행한 결과, 전체 운전 기간 동안 일반 BAC 공정에 비해 강화 BAC 공정에서 Br2-MP의 제거효율이 더 높은 것으로 나타났다. 특히, 저온(5℃)과 짧은 EBCT(5분)에서 강화 BAC 공정과 일반 BAC 공정의 Br2-MP 제거효율은 큰 차이를 나타내었다. 5℃와 25℃에서 일반 BAC 공정의kbio는 각각 0.0229 min-1, 0.0612 min-1, 강화 BAC 공정의 kbio는 각각 0.0470 min-1, 0.1421 min-1로 강화 BAC 공정이 일반 BAC 공정에 비해 2배 이상 빠른 Br2-MP 생분해능을 나타내었으며, 이러한 결과는 회분식 실험결과와도 유사하였다. 또한, 하절기 잦은 EBCT 변경에 대한 영향을 시뮬레이션한 실험에서 강화 BAC 공정은 일반 BAC 공정에 비해 상대적으로 안정적인 Br2-MP 제거효율을 유지하였다. 결론 : 강화된 BAC 공정은 일반 BAC 공정에 비해 우수한 미량오염물질 생물분해능을 나타내었다. 다만 경제성(인산염과 과산화수소 비용 등)과 수질을 고려할 때 하절기와 같이 EBCT가 단축되거나 수온이 낮아지는 동절기에 한하여 간헐적으로 강화 BAC 공정을 운영하는 것도 효율적인 대안으로 평가되었다. Objectives : In this study, the removal efficiency of micropollutants in the biological activated carbon (BAC) process was investigated, and a method for improving the removal efficiency of micropollutants in the BAC process of water treatment plants was proposed.Methods : Dibromo-methylparaben (Br₂-MP) was selected as the target micropollutant. Batch and lab-scale column experiments were conducted to evaluate the removal efficiencies of Br₂-MP in the conventional BAC process and the BAC with enhanced biofilm properties by the addition of phosphorus (P) and hydrogen peroxide (H₂O₂). Biodegradation kinetics were evaluated using results from batch and lab scale column experiments.Results and Discussion : As a result of comparing the removal efficiency of Br₂-MP in a batch experiment with the same biomass concentrations (2.0±0.2×10⁷ cells), the biodegradation rate constant (<i>k</i>_bio) of the enhanced BAC process was found to be 1.2 times higher than that of the conventional BAC process due to its higher biological activity (enhanced BAC: 3.4±0.3 mg·C/g·hr, conventional BAC: 2.9±0.4 mg·C/g·hr). Comparison of removal efficiencies of Br₂-MP in batch experiments with the same wet weight of BAC (1 g) showed that the biodegradation rate constant (<i>k</i>_bio) of the enhanced BAC process was 1.9 times higher than that of conventional BAC process due to higher biomass (enhanced BAC: 3.5±0.4 µg·ATP/g·GAC, conventional BAC: 2.3±0.2 µg·ATP/g·GAC). Through the batch experiments, the enhanced BAC process was efficient in removing Br₂-MP via increasing both biomass concentrations and activity of attached microorganisms. Lab-scale column experiments conducted under different water temperatures (5 and 25℃) and empty bed contact time (EBCT: 5-40 min) conditions showed higher removal efficiency of Br₂-MP in the enhanced BAC process than the conventional BAC process throughout the entire period of operation. In particular, the removal efficiency of Br₂-MP between the enhanced and conventional BAC processes showed significant differences at low temperature (5℃) and short EBCT (5 min). At 5℃ and 25℃, the kbio of the conventional BAC process was 0.0229 min^-1 and 0.0612 min^-1, respectively, and the <i>k</i>_bio of the enhanced BAC process was 0.0470 min^-1 and 0.1421 min^-1, respectively, These results showed that the enhanced BAC process had two times higher biodegradability of Br₂-MP than the conventional BAC process. These results showed a similar trend to the results from the batch experiment. In an experiments simulating the impact of frequent EBCT changes during summer, the enhanced BAC process maintained a relatively stable removal efficiency of Br₂-MP compared to the conventional BAC process.Conclusion : The enhanced BAC process showed superior biodegradation of micropollutant compared to the conventional BAC process. Considering economic costs (e.g., costs of adding phosphate and hydrogen peroxide) and water quality, it appears to be an efficient alternative to operate the enhanced BAC process intermittently, limited to cases where EBCT is shortened, such as summer, or when water temperature is low, such as in winter.

숙련공에 의한 목탄제조과정 중 전통식 탄화로 내의 온도변화 (Ⅰ)

권구중(Gu-Joong Kwon),박형수(Hyung-Soo Park),이성재(Sung-Jae Lee),권성민(Sung-Min Kwon),이귀현(Gwi-Hyun Lee),김남훈(Nam-Hun Kim) 한국산림바이오에너지학회 2008 산림바이오에너지 Vol.27 No.1

숙련자에 의한 목탄제조과정 중 전통식 탄화로내의 온도변화와 목탄의 수율을 조사하였다. 온도 측정에는 플라티늄을 원료로한 R형의 열전지와 니켈을 원료로한 K형의 열전지를 이용하였다. R형의 온도측정범위는 0∼1600℃, K형은 0∼1200℃로 탄화로 내부는 R형을, 굴뚝부위는 K형을 사용하여 온도를 측정하였다. 탄화과정은 5일에서 6일 정도가 소요되었다. 탄재의 착화시 탄화로 내부의 온도는 약 700∼800℃였고 연통부위 온도는 약 80∼90℃였다. 목초액을 얻는 동안의 탄화로 내부온도는 약 600℃였고 굴뚝부위는 약 80∼90℃였다. 정련단계에 이르기까지 탄화로 내부온도는 증가하여 정련단계에서는 900∼1100℃의 고온에 달하였다. 정련단계에서 굴뚝의 온도도 크게 올라 약 600℃에 달하였다. 목탄의 수율은 9.8∼12.3%였다. 본 연구에서 전통식 탄화로를 이용한 숙련자의 목탄제조 과정 중의 온도변화 경과곡선과 목탄의 수율이 밝혀졌다. 얻어진 온도변화 경과곡선은 초심자의 제탄과정에서 지표의 하나로 이용될 수 있을 것이다. This study was performed to investigate the variation of temperature in a Korean traditional kiln controlled by an expert during carbonization process of wood. The yield of charcoal was also investigated. Two kinds of thermocouples, R-type and K-type, were used for measuring temperatures. Temperature tolerance of the R-type thermocouple prepared from platinum was from 0℃ to 1600oC and that of K-type thermocouple prepared from Nickel was from 0℃ to 1200℃. R-type was used for measuring temperature in the kiln while the K-type for measuring temperature in chimney. In this traditional kiln system, carbonization process was completed in five to six days. In the kiln, the ignition temperature was ranged from 700℃ to 800℃. During gathering wood vinegar, the temperature was kept around 600℃. And then the temperature were increased gradually prior to be refined. Finally, the temperature in refining process was reached to maximum point, 1000±10℃. In the chimney, the temperature was increased gradually from ca. 80℃ at ignition to ca. 600℃ at refining. The yield of wood charcoal was 9.8 to 12.3%. In this study, we showed the temperature profile through carbonization process in the traditional kiln and the yield of wood charcoal. The temperature profile can be used for beginner during carbonization process as a guideline.

Effect of carbonization temperature on electrical conductivity of carbon papers prepared from petroleum pitch-coated glass fibers

허건영,박수진,유윤종 한국공업화학회 2013 Journal of Industrial and Engineering Chemistry Vol.19 No.3

Carbon papers were prepared wet-laid process of pitch-coated carbonized glass fibers, and the electrical conductivity of conductive carbon paper was investigated based on the structural and morphology of pitch-coated carbonized glass fibers prepared by different carbonization temperature. The electrical conductivity of the carbon paper which made of pitch-coated carbonized glass fibers was decreased at 900 8C and 1000 8C of carbonization temperature of pitch-coated glass fibers. This is due to the low stacked crystalline structure of pitch-coated glass fibers which is resulting from a basal carbon loss, in situ gasification and pyrolysis of low molecular compounds of coated pitch, at high carbonization temperature.

Effect of carbonization temperature on electrical conductivity of carbon papers prepared from petroleum pitch-coated glass fibers

Heo, G.Y.,Yoo, Y.J.,Park, S.J. Korean Society of Industrial and Engineering Chemi 2013 Journal of industrial and engineering chemistry Vol.19 No.3

Carbon papers were prepared wet-laid process of pitch-coated carbonized glass fibers, and the electrical conductivity of conductive carbon paper was investigated based on the structural and morphology of pitch-coated carbonized glass fibers prepared by different carbonization temperature. The electrical conductivity of the carbon paper which made of pitch-coated carbonized glass fibers was decreased at 900<SUP>o</SUP>C and 1000<SUP>o</SUP>C of carbonization temperature of pitch-coated glass fibers. This is due to the low stacked crystalline structure of pitch-coated glass fibers which is resulting from a basal carbon loss, in situ gasification and pyrolysis of low molecular compounds of coated pitch, at high carbonization temperature.

탄소섬유강화복합소재의 고압수지이송성형공정에서 금형 내 캐비티의 압력 및 온도신호에 따른 성형특성

한범정(Beom-Jeong Han),정용채(Yong-Chai Jeong),김성렬(Sung-Ryul Kim),김노원(Ro-Won Kim),강명창(Myung Chang Kang) 한국기계가공학회 2017 한국기계가공학회지 Vol.16 No.6

The high-pressure resin transfer molding (HP-RTM) process has a very effective for the mass production of carbon fiber reinforced plastic (CFRP) for light weight in the automotive industry. In developing robust equipment, new process and fast cure matrix systems reduces significantly the cycle time less than 5 minutes in recent years. This paper describes the cavity pressure, temperature and molding characteristics of the HP-RTM process. The HP-RTM mold was equipped with two cavity pressure sensors and three temperature sensors. The cavity pressure characteristics of the HP-RTM injection, pressurization, and curing processes were studied. This experiment was conducted with selected process parameters such as mold cap size, maximum press force, and injection volume. Consequently, this monitoring method provides correlations between the selected process parameters and final forming characteristics in this work.

슬러지를 이용한 유기산 발효공정의 외부 탄소원으로 활용

김영규,김인배,김민호 한국환경보건학회 2001 한국환경보건학회지 Vol.27 No.4

The sludge wastes fermentation process reactors were operated to produce the VFAs(volatile fatty acids) as supplemental carbon sources and to determine the optimum operating conditions. The experiment was carried out by varied mixture ration of 400:0 350:30 300:100 200:200 and operating temperature 20℃ 30℃ and 40℃ The results were as follows: Higher VFAs production rate observed at higher mixed ratio of primary sludge. When the mixed ratio of primary sludge and return sludge were 400:0 350:50 300:100 200:200 respectively. VFAs production are were 829.6mg/l 944.2 mg/l 597.9mg/ml an d441.6 mg/l , respectively. the yield of VFAs increased with temperature, but decreased with initial TSS concentration Because fermented sludge has relatively low nitrogen and phosphorus and relatively high VFAs it can be used as a substitute for external carbon in biological nutrient removal process.

BAC 공정에서 파라벤 및 할로겐화 파라벤류의 생물분해 특성 및 동력학 평가

염훈식(Hoon-Sik Yoom),손희종(Hee-Jong Son),김희영(Hee-Young Kim),이윤호(Yun-Ho Lee),류동춘(Dong-Choon Ryu),김창원(Chang-Won Kim) 대한환경공학회 2018 대한환경공학회지 Vol.40 No.7

상수원수 중에 잔존하는 methylparaben류(MPs)가 정수처리 공정으로 유입되면 염소와 반응하여 할로겐화된 paraben 류가 생성된다. 본 연구에서는 할로겐화된 paraben류들의 생물활성탄 공정에서의 생물분해 제거 특성에 대해 평가하였다. Methylparaben (MP)와 할로겐화 MP류 5종의 생물분해능은 MP가 가장 높았으며, chloro-methylparaben (Cl-MP), bromomethylparaben (Br-MP), dichloro-methylparaben (Cl₂-MP), bromo,chloro-methylparaben (Br,Cl-MP) 및 dibromo-methylparaben (Br₂-MP) 순으로 나타났다. MP, Cl-MP 및 Br-MP는 수온 5℃에서도 empty bed contact time (EBCT) 5분에서 완전 제거되었으나, Cl₂-MP와 Br₂-MP의 경우는 EBCT 15분에서도 각각 79.8%와 65.3% 제거되었으며, 수온 25℃, EBCT 15분의 조건에서도각각 99.1% 및 94.6%의 제거율을 나타내어 BAC 공정에서 제어하기가 어려운 물질로 평가되었다. BAC 공정에서 수온 5℃~25℃에서의 Br₂-MP의 생물분해 속도상수(kbio)와 반감기(t1/2)는 각각 0.0671 min<SUP>-1</SUP>~0.2358 min<SUP>-1</SUP> 및 2.9 min~10.3 min이었으며, Cl₂-MP의 경우는 kbio와 t1/2이 각각 0.1005 min<SUP>-1</SUP>~0.3458 min<SUP>-1</SUP> 및 2.0 min~6.9 min이었다. Cl₂-MP, Br,Cl-MP 및 Br₂-MP의 생물분해 중간생성물질로 MP가 생성되며, BAC 공정 처리수 중에 MP가 잔존할 경우 후염소 처리에 의해 할로겐화-MP류의 재생성 가능성이 있어 이에 대한 추가적인 연구가 필요하였다. When the methylparabens (MPs) remaining in the raw water is introduced into the water treatment process, halogenated parabens are produced by reacting with chlorine. In this study, biodegradation characteristics of halogenated parabens in biological activated carbon (BAC) process were evaluated. The biodegradability of methylparaben (MP) and five halogenated MP species were highest in MP, followed by chloro-methylparaben (Cl-MP), bromo-methylparaben (Br-MP), dichloro-methylparaben (Cl₂-MP), bromo,chloro-methylparaben (Br,Cl-MP) and dibromo-methylparaben (Br₂-MP). MP, Cl-MP and Br-MP were completely removed under conditions of water temperature 5℃ and EBCT 5 min. In the case of Cl₂-MP and Br2-MP, 79.8% and 65.3% of removal rate were represented at EBCT 15 min and 99.1% and 94.6% of Cl₂-MP and Br₂-MP were removed under conditions of water temperature 25℃ and EBCT 15 min. These results indicate that these compounds are difficult to control the BAC process. The biodegradation rate constants (kbio) and half-life (t1/2) of Br2-MP at the water temperature of 5℃ to 25℃ in the BAC process were 0.0671 min<SUP>-1</SUP>~0.2358 min<SUP>-1</SUP> and 2.9 min to 10.3 min, respectively, and in case of Cl₂-MP, kbio and t1/2 were 0.1005 min<SUP>-1</SUP>~0.3458min<SUP>-1</SUP> and 2.0 min~6.9 min, respectively. MP is produced as a biodegradation intermediate of Cl₂-MP, Br, Cl-MP and Br₂-MP, and if MP remains in the BAC-treated water, the possibility of regeneration of halogenated-MPs by post-chlorination and further study is needed.

BAC 공정에서의 고지혈증 치료제 생물분해 특성

염훈식(Hoon-Sik Yoom),손희종(Hee-Jong Son),류동춘(Dong-Choon Ryu),유평종(Pyung-Jong Yoo) 大韓環境工學會 2017 대한환경공학회지 Vol.39 No.3

생물활성탄 공정과 안트라사이트를 여재로 사용한 biofilter에서 공탑 체류시간(EBCT)과 수온의 변화에 따른 8종의 고지혈증 치료제류(blood lipid regulator agents, BLLAs)의 생물분해 특성을 평가하였다. 수온 8℃, 16℃ 및 24℃에서 공탑 체류시간을 5분~15분까지 변화시켰다. 생물활성탄 공정에서 고지혈증 치료제류 8종의 생물분해 제거율은 공탑 체류시간과 수온의 변화에 많은 영향을 받았으며, 공탑 체류시간과 수온이 증가할수록 생분해 제거율이 증가하였다. 고지혈증 치료제류의 종류에 따른 생물활성탄 공정에서 생분해 제거율은 statin계의 경우 simvastatin이 가장 높았으며 다음으로 mevastatin, fluvastatin 및 atorvastatin 순이었다. 또한, Fibrate계 고지혈증 치료제들의 생물분해능은 fenofibrate가 가장 높았으며 다음으로 gemfibrozil, bezafibrate, clofibric acid순이었다. BAC 공정에서 생물분해 제거능이 가장 낮은 clofibric acid와 atorvastatin의 생물분해 속도 상수(Kbio)는 수온이 8℃에서 24℃로 상승하였을 경우, 각각 0.0075 min<SUP>-1</SUP>과 0.0122 min<SUP>-1</SUP>에서 0.0540 min<SUP>-1</SUP>과 0.0866 min<SUP>-1</SUP>으로 증가하여 각각 7.2배 및 7.1배 정도 증가하였다. In this study, We investigated the effects of water temperature and empty bed contact time (EBCT) on the biodegradability of 8 blood lipid lower agents (BLLAs) in biological activated carbon (BAC) process. Experiments were conducted at three water temperatures (8℃, 16℃ and 24℃) and three EBCTs (5 min, 10 min and 15 min). Increasing water temperature and EBCT increased the biodegradation efficiency of BLLAs in BAC process. Simvastatin and fenofibrate were the highest biodegradation efficiency, but atorvastatin and clofibric acid were the lowest. The kinetic analysis suggested a pseudo-first-order reaction model for biodegradation of 8 BLLAs at various water temperatures and EBCTs. The pseudo-first-order biodegradation rate constants (kbio) of clofibric acid and atorvastatin were 0.0075 min<SUP>-1</SUP> and 0.0122 min<SUP>-1</SUP> at 8℃, and were 0.0540 min<SUP>-1</SUP> and 0.0866 min<SUP>-1</SUP> at 24℃, respectively. By increasing the water temperature from 8℃ to 24℃, the biodegradation rate constants (kbio) were increased 7.1~7.2 times.

개량형탄화로를 이용한 제탄과정 중 탄화로 내,외벽 온도변화 및 목탄 특성

권구중 ( Gu Joong Kwon ),권성민 ( Sung Min Kwon ),장재혁 ( Jae Hyuk Jang ),황원중 ( Won Joung Hwang ),김남훈 ( Nam Hun Kim ) 한국목재공학회 2011 목재공학 Vol.39 No.3

The study was performed to investigate the characteristics of charcoal and temperature change of a kiln`s inner and outer walls in carbonization process using improved kiln. In this kiln system, carbonization process was completed in eight days In the kiln, the ignition temperature was kept about 720°C And then the temperature were increased gradually prior to be refined. Finally, the temperature in refining process was reached to maximum point, 1,000°C In the chimney, the temperature was increased gradually from 90°C at ignition to 750°C at refining. The temperature change of the kiln wall resembles a temperature change progress curve during a carbonization process The highest temperature of the kiln wall that appeared hy a carbonization process was around 500°C As a result of having measured an inner wall and the outer wall of the kiln using an infrared thermography camera, it was judged with there being considerable latent heat on kiln wall and ceiling. Fixed carbon contented of charcoal was 85.9~89.9%. Refining degree of charcoal, hardness, calorific value and pH were I, 12, 7,047- 7,456 kcal/kg, 9.0~9.9, respectively. The yield of wood charcoal was 138% and compared to conventional kiln`s yield increased 1.5%.