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무회분 석탄 생산을 위한 온순조건 용매추출 공정의 경제성 분석
최호경 ( Ho Kyung Choi ),김상도 ( Sang Do Kim ),유지호 ( Ji Ho Yoo ),전동혁 ( Dong Hyuk Chun ),임정환 ( Jeong Hwan Lim ),임영준 ( Young Joon Rhim ),이사훈 ( Si Hyun Lee ) 한국화학공학회 2012 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.50 No.3
Economic feasibility of the process for a coal extraction under mild condition, which will produce ash-free coal at a temperature lower than that of coal softening, was analyzed. To this end, the plant of 6000 t/d in capacity was assumed to be constructed near a coal mine in Indonesia, and the IRR, NPV, B/C ratio, and DPP of the plant were calculated based on $96 million investment cost and 15 years service life. The IRR, NPV, B/C ratio, and DPP of the plant were calculated to be 31%, $87 million, 1.08, and 3.9 years, respectively, and which satisfied the evaluation criteria of investment. The economic feasibility of the plant was mainly dependent on the price of the coal initially fed and the residue coal remaining after the extraction, according to sensitivity analysis.
감압건조, 희석침전, 분무건조 방식으로 제조된 무회분석탄의 특성
권호중 ( Ho Jung Kwon ),최호경 ( Ho Kyung Choi ),조완택 ( Wan Taek Jo ),김상도 ( Sang Do Kim ),유지호 ( Ji Ho Yoo ),전동혁 ( Dong Hyuk Chun ),임영준 ( Young Joon Rhim ),임정환 ( Jeong Hwan Lim ),이시훈 ( Si Hyun Lee ),이영우 ( You 한국화학공학회 2016 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.54 No.2
Solid ash-free coal (AFC) samples recovered from solvent-extracted solution by vacuum drying, dilution precipitation and spray drying methods were compared in terms of physical properties and chemical structure. AFC was prepared by using Kideco coal (Indonesian sub-bituminous coal) and polar N-methyl-2-pyrrolidone (NMP) solvent as raw materials. The physical properties of the AFCs were characterized with proximate, ultimate, and calorific value analysis. In analyzing the chemical structure, FTIR and NMR were used. the proximate analysis showed much reduced ash in the AFCs compared to parent raw coal. The FTIR result showed that the extraction solvent was not fully removed from the AFC prepared by vacuum drying. However, the solvent was not detected in the AFC recovered by using dilution precipitation. Dilution precipitation has advantages over the other two methods, since it can be done at relatively low temperature and separate ash-free coal from extraction solvent more effectively.
상온에서의 용매 처리를 통한 저등급 석탄의 표면물성 및 자연발화 특성 변화
조완택 ( Wan Taek Jo ),최호경 ( Ho Kyung Choi ),김상도 ( Sang Do Kim ),유지호 ( Ji Ho Yoo ),전동혁 ( Dong Hyuk Chun ),임영준 ( Young Joon Rhim ),임정환 ( Jeong Hwan Lim ),이시훈 ( Si Hyun Lee ) 한국화학공학회 2013 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.51 No.5
This study investigated the spontaneous combustion behavior of solvent-treated low rank coals. Indonesian lignite (a KBB and SM coal) and sub-bituminous (a Roto coal) were mixed with non-polar 1-methyl naphthalene (1MN) either by mechanical agitation or ultrasonication. The property change associated with 1MN treatment was then analyzed using proximate analysis, calorific value analysis, Fourier transform infrared (FT-IR), X-ray photoelectron spectroscopy and moisture re-adsorption test. Susceptibility to spontaneous combustion was evaluated using crossingpoint temperature (CPT) measurement along with gas analysis by GC. A FT-IR profile showed that oxygen functional groups and C-H bonding became weaker when treated by 1 MN. XPS results also indicated a decrease of the oxygen groups (C-O-, C=O and COO-). Increased hydrophobicity was found in the 1MN treated coals during moisture readsorption test. A CPT of the treated coals was ~20 oC higher than that of the corresponding raw coals and the ultrasonication was more effective way to enhance the stability against spontaneous combustion than the agitation. In the gas analysis less CO and CO2 were emitted from 1MN treated coals, also indicating inhibition of pyrophoric behavior. The surface functional groups participating in the oxidation reaction seemed to be removed by the ultrasonication more effectively than by the simple mechanical agitation.
엘리트 쇼트트랙 스피드 스케이팅 선수들의 스포츠 손상에 대한 역학 연구
김은국(Kim, Eun-Kuk),최호경(Choi, Ho-Kyung) 한국체육과학회 2017 한국체육과학회지 Vol.26 No.2
The purpose of this study was to investigate sports injuries which were developed by Korean elite short track speed skaters. Seventeen elite skaters who belonged to S-City Team were enrolled in this study. The epidemiologic data were collected by an interviewer-administered questionnaire based on injury report form of the International Olympic Committee. A total of 53 injuries were reported, and 25 injuries and 28 injuries were developed in adolescents and adult skaters, respectively. In adolescent skaters, incidence rate (IR) of all injuries was 3.28 injuries/1000 athlete exposures (AEs), and the IR of the knee injuries was the highest (3.64 injuries/10000AEs). Injuries during training comprised 96% of all injuries and contact injuries were 48%. Serious injuries that needed to be absent from trains or competitions more than one day were 40% and 44% of all injures were still inducing pain with exercise. In adult skaters, total IR was 4.59 injuries/1000AEs and the highest IR was 4.13 injuries/1000AEs in knee joint. Injuries during training comprised 82.1% of all injuries and contact injuries were 53.6%. Serious injuries were 28.6% and 28.6% were still inducing pain with exercise. In conclusion, the results of this study demonstrated IRs and characteristics of sports injuries, which could be helpful to provide useful information for preparing preventive measures against the sports injuries in elite short track speed skaters.
연구 논문 : 온순조건과 고온조건에서 용매 추출한 석탄의 특성 비교
박근용 ( Keun Yong Park ),최호경 ( Ho Kyung Choi ),김상도 ( Sang Do Kim ),유지호 ( Ji Ho Yoo ),전동혁 ( Dong Hyuk Chun ),임영준 ( Young Joon Rhim ),임정환 ( Jeong Han Lim ),이시훈 ( Si Hyun Lee ),나병기 ( Byung Ki Na ) 한국공업화학회 2012 공업화학 Vol.23 No.6
본 연구에서는 온순조건에서 용매 추출된 석탄의 물성과 추출특성을 고온조건에서 추출된 석탄의 것과 비교하였다. 석탄의 용매 추출 특성을 알아보기 위해 추출실험에는 아역청탄(Kideco 탄)과 극성 용매인 N-methyl-2-pyrrolidinone (NMP)을 사용하였다. 온순조건과 고온조건에서 석탄의 용매 추출 특성을 알아보기 위해 추출온도 변화, 용매 재사용에 따른 추출 특성 변화에 대한 실험을 하였다. 실험결과 추출온도가 증가할수록 추출수율과 추출탄의 발열량은 증가하였고, 회분농도는 감소하였다. FT-IR 분석 결과 고온조건(350 ℃)에서 추출한 추출탄의 표면에 C=O 아미드 결합, 방향족 에테르, 그리고 지방족 에테르 그룹들이 온순조건(150∼300 ℃)에서 추출한 것에 비해 증가하는 것으로 나타났다. MALDI-TOF/MS 분석 결과 온순조건에서는 300∼500 m/z 범위 이하의 작은 분자들이 주로 추출되었고, 고온조건에서는 500∼1500 m/z 범위에 걸쳐 상대적으로 큰 분자들까지 추출됨을 확인하였다. In this study, we compare various physicochemical properties of solvent extracted coals obtained at both mild and high temperature conditions. In order to characterize the extraction behavior, experiments were performed using a sub-bituminous coal (Kideco) and a polar solvent (N-methyl-2-pyrrolidinone, NMP), where the extraction temperature and the effect of solvent recycling were evaluated. As the extraction temperature increased up to 350 ℃, an extraction yield and a calorific value of the extracted coal increased, while an ash content of the extracted coal decreased. FT-IR results revealed that the surface of the coal extracted at 350 ℃ was found to contain more amide, aromatic ester, and aliphatic ether groups than that at the lower temperatures. The result of MALDI-TOF/MS analysis confirmed that the smaller molecules with 300∼500 m/z were extracted at a mild condition, while the bigger molecules in the range of 500∼1500 m/z were extracted at the high temperature.
한국체육대학교 학생들의 도핑에 대한 지식, 믿음 및 성향
김은국 ( Eun-kuk Kim ),최호경 ( Ho-kyung Choi ) 한국체육대학교 체육과학연구소 2015 스포츠사이언스 Vol.32 No.2
In the strategy for the doping control, attitudes and beliefs are considered an index of doping behaviour, relating the use of banned substances to greater leniency towards doping. The aim of this study was to quantitatively measure the doping related attitudes, beliefs and knowledge among non-elite students attending Korea National Sport University. Data were collected by questionnaires among the students (n=190). Outcome measures included doping knowledge, behavior and attitude (Performance Enhancement Attitude Scale; PEAS). PEAS scores were 41.11±13.82, in which there was no significant difference between sexes. About eighty-seven percent of students were unaware of banned substances. A few male students admitted the past use of doping knowingly or inadvertently and 5 students reported that they knew others doping, and they demonstrated higher PEAS scores. Most students demonstrated negative attitudes toward doping in 14 items among 17 PEAS questionnaires. This study may provide Sport University students with educational strategy for effective anti-doping program.