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최석천(Seukcheun choi),이해종(Haejong Lee),김세현(Sehyun Kim),정한식(Hanshik Chung),이광영(Kwangyoung Lee),정효민(Hyomin Jeong) 한국자동차공학회 2003 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
In this study. a computer analysis has been developed for predicting the pipe pressure of the intake and exhaust manifold. To obtain the boundary conditions for a numerical analysis, one dimensional and non-steady gas dynamic calculation is performed by using the MOC(Method Of Characteristic). The main numerical parameters are the variation of the engine revolution to calculate the pulsating flow which the intake and exhaust valves are working. The comparison of exhaust pressure in case of numerical results is quite matched with in case of experimental results. When engine revaluation is increased, the pressure amplitude showed a high value, but the pressure frequency was decreased.<br/>
휘발성 유기 화합물 및 암모니아 직접 연소를 통한 배기가스 특성
김종수,최석천,정수화,목진성,김두범,Kim, JongSu,Choi, SeukCheun,Jeong, SooHwa,Mock, ChinSung,Kim, DooBoem 한국청정기술학회 2022 청정기술 Vol.28 No.2
The semiconductor process currently emits various by-products and unused gases. Emissions containing pollutants are generally classified into categories such as organic, acid, alkali, thermal, and cabinet exhaust. They are discharged after treatment in an atmospheric prevention facility suitable for each exhaust type. The main components of organic exhaust are volatile organic compounds (VOC), which is a generic term for oxygen-containing hydrocarbons, sulfur-containing hydrocarbons, and volatile hydrocarbons, while the main components of alkali exhaust include ammonia and tetramethylammonium hydroxide. The purpose of this study was to determine the combustion characteristics and analyze the NO<sub>X</sub> reduction rate by maintaining a direct combustion and temperature to process organic and alkaline exhaust gases simultaneously. Acetone, isopropyl alcohol (IPA), and propylene glycol methyl ether acetate (PGMEA) were used as VOCs and ammonia was used as an alkali exhaust material. Independent and VOC-ammonia mixture combustion tests were conducted for each material. The combustion tests for the VOCs confirmed that complete combustion occurred at an equivalence ratio of 1.4. In the ammonia combustion test, the NO<sub>X</sub> concentration decreased at a lower equivalence ratio. In the co-combustion of VOC and ammonia, NO was dominant in the NO<sub>X</sub> emission while NO<sub>2</sub> was detected at approximately 10 ppm. Overall, the concentration of nitrogen oxide decreased due to the activation of the oxidation reaction as the reaction temperature increased. On the other hand, the concentration of carbon dioxide increased. Flameless combustion with an electric heat source achieved successful combustion of VOC and ammonia. This technology is expected to have advantages in cost and compactness compared to existing organic and alkaline treatment systems applied separately.
화력발전 시스템 및 설비 개선 실증을 위한 열물질정산 공정모델 개발
안형준(Hyungjun Ahn),최석천(Seukcheun Choi),이영재(Youngjae Lee),김범수(Beom Soo Kim) 한국연소학회 2018 한국연소학회지 Vol.23 No.1
Heat and mass balance process modeling has been conducted for a coal-firing power plant to be used as a testbed facility for development of various plant systems and equipment. As the material and design of the boiler tube bundle and fuel conversion to the biomass have become major concerns, the process modeling is required to incorporate those features in its calculation. The simulation cases for two different generation load show the satisfying results compared to the operational data from the actual system. Based on the established process conditions, the hypothetical case using wood pellet has also been simulated. Additional calculations for the tube bundle has been conducted regarding the changes in the tube material and design.
머플러에 유입되는 배기가스의 유동 압력에 관한 수치해석
이중섭(Chungseub Yi),최석천(Seukcheun Choi),서정세(Jeongse Suh),정한식(Hanshik Chung),정효민(Hyomin Jeong),배태열(Taeyeol Bae) 한국자동차공학회 2004 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
This study represents Numerical study on the fluid flow characteristics of exhaust gas into the motorcycle muffler. Numerical analysis with Computational Fluid Dynamics(CFD) was carried out to investigate the exhaust gas that flow into the motorcycle muffler. The STAR-CD S/W used for the three dimensional steady state CFD analysis in a muffler. The Navier-Stokes Equation is? solved with the SIMPLE method with a general Cartesian coordinates system. RNG k-e and MARS(Monotone Advection and Reconstruction Scheme) were used for turbulence model and convection term, respectively.
미이용 바이오매스의 이산화탄소 활성화를 통한 바이오카본 생산: 포름알데하이드 및 아세트알데하이드 제거 특성
김종수(JongSu Kim),최석천(SeukCheun Choi),이은도(Uendo Lee),박은석(EunSeuk Park),정수화(Soohwa Jeong) 한국청정기술학회 2021 청정기술 Vol.27 No.4
본 연구에서는 미이용 바이오매스인 3급 목재펠렛 및 커피박을 이용하여 바이오카본을 생산하고 이를 통하여 저분자 극성 휘발성 유기화합물인 포름알데하이드 및 아세트알데하이드 제거 성능 실험을 수행하였다. 바이오카본 생산 실험은 이산화탄소를 활성화제로 사용하여 고정층 반응기에서 수행하였다. 활성화 실험 시 반응온도 900 ℃ 및 이산화탄소 1 L min<SUP>-1</SUP>으로 반응조건을 고정하여 진행하였다. 활성화 실험 결과 1급 목재펠렛으로부터 생산한 바이오카본의 BET 비표면적이 약 788 ㎡ g<SUP>-1</SUP>으로 가장 높음을 알 수 있었고 커피박으로부터 생산한 바이오카본이 약 544 ㎡ g<SUP>-1</SUP>으로 가장 낮게 나타났다. 본 실험을 통해 생산된 바이오카본은 대부분 마이크로 기공을 가진 것으로 나타났다. 바이오매스 원료 내 회분의 함량이 낮을수록 바이오카본의 비표면적이 높아지는 것으로 나타났다. 포름알데하이드 및 아세트알데하이드 제거 실험 결과 1급 및 3급 목재펠렛으로부터 생산한 바이오카본에 비해 커피박으로부터 생산한 바이오카본이 더욱 우수한 흡착 성능을 보여주었다. 추가적으로 상용 첨착 활성탄과 커피박으로부터 생산한 바이오카본의 비교 실험을 진행하였다. 포름알데하이드 제거 성능은 상용 첨착 활성탄이 우수한 반면 아세트알데하이드 제거에는 커피박으로부터 생산한 바이오카본이 우수한 것으로 나타났다. In this study, bio-carbons were produced by activation process from unused biomass (Grade 3 wood pellet and spent coffee grounds) to determine the removal performance of formaldehyde and acetaldehyde. The activation experiments were conducted in a fixed bed reactor using CO₂ as an activation agent. The temperature of the activation reactor and input of CO₂ were 900 ℃ and 1 L min<SUP>-1</SUP> for all the experiments. The maximum BET surface area of about 788 ㎡ g<SUP>-1</SUP> was obtained for bio-carbon produced from Grade 1 wood pellet, whereas about 544 ㎡ g<SUP>-1</SUP> was achieved with bio-carbon produced from spent coffee grounds. In all the experiments, the bio-carbons produced were mainly found to have micro-porous nature. A lower ash amount in raw material was favored for the high surface area of bio-carbons. In the removal test of formaldehyde and acetaldehyde, the bio-carbon produced from spent coffee grounds showed excellent adsorption performance compared with woody biomass (Grade 1 wood pellet and Grade 3 wood pellet). In addition, the comparative experiment of commercial impregnated activated carbon and bio-carbon produced from spent coffee grounds was conducted. In terms of formaldehyde removal performance, the commercial impregnated bio-carbon was excellent, while bio-carbon produced from spent coffee grounds was excellent in acetaldehyde removal.