제 6 장 오염물질의분석법 Prof. Byung-Chul Choi School of Mechanical Systems Engineering Chonnam Nat. Univ. 제동토크및제동동력 (1) Prony Brake l R q ds Ff Fw 회전체와고정자사이의마찰력 : 고정자에힘이작용 Work W, dw = Ff R dq ds Brake torque, T = Ff R = Fw l Brake power, P b = dw/dt = Ff Rdq/dt = FfRw = Fwlw = T w = T(N.m)(2pN(rps)) x 10-3 1
(2) 수동력계물의마찰력과교반력이용. - 마찰력 : 회전자와고정자사이의유체점성력이용. - 교반형 : 회전자의임펠러에서고정자의임펠러에유체가이동하는결합력사용 마찰력형 교반형 (3) 전기동력계 (a) DC Dynamometer (b) AC Dynamometer 측정정밀도가높고부하조절범위가높다. 2
(c) Eddy Current(EC) Dyno. - 케이싱에고정한환상의권선여자코일, 치차모양의회전자, 그사이의와전류링으로구성. - 여자코일에자로가형성, 회전자로자로를끊어주면, 와전류링에와전류가발생하여제동력을얻는다. - 와전류에의해열발생, 냉각수로냉각. - 토크는 Prony Dyno. 와같이케이싱의요동이용으로측정. EC Dynamometer 원리 Electro-magnetic 3
Dynamometer 성능비교 수동력계 전기동력계 AC DC EC 1. 기능 흡수 흡수 / 구동 흡수 / 구동 흡수 2. 조작성 양호 양호 양호 양호 3. 안정성 조금나쁨 양호 양호 조금좋음 4. 과도응답성 조금나쁨 양호 양호 조금좋음 5. 정밀도 조금나쁨 양호 양호 조금좋음 6. 전력회생 불가 가능 가능 불가 7. 유틸리티 냉각수 전원 전원 냉각수 8. 가격 저가 고가 고가 저가 자동차배출가스의샘플링장치 4
분광기분석법 Bear-Lambert Law A absorbation cell C diaphragm of capacitive sensor D detector E IR emitter F compensation cell M rotating modulator R reference cell S differential measurement signal (a) Positive-filter analyzer A absorbation cell C diaphragm of capacitive sensor D detector E IR emitter F compensation cell M rotating modulator I = e -kcl N cell containing gas to be analyzed S differential measurement signal (b) Negative-filter analyzer NDIR 분석기 k : 흡수계수 c : 가스농도 L : 셀길이 CO, CO 2 NDIR 분석기의구조 (Horiba 사 ) 5
반도체다이오드레이저분광기 C I - 단색광선발산 - 파장은조작온도로조절 - 가스농도 Bear-Lambert Law I = e -kcl k : 흡수계수 c : 가스농도 L : 셀길이 - 다성분동시분석, 실시간측정가스흐름에서직접측정 반도체다이오드레이저분광기 H 2 O spectra recorded during HCCI engine 6
FTIR 분광기원리 - 간섭계이용 : 2.5-14 μm 이용 적외선 -beamsplit- 두광 - 가동거울 1- 가동거울 2- 고정거울 - 반사 -beamsplit( 두가동거울동일축을중심으로회전 )- - 재입사한두적외선에광로차 (2) 연속스펙트럼파장은광로차가변할때간섭계에서맥동 (3) 광로차로위상이어긋난적외선이검출기에도달 (4)Interferogram (5)Fourier Transform(PC) 파장별적외선강도데이터 FTIR 분광기원리 (6) 간섭계를떠난빛이가스셀을통과 (7) 각기다른가스의흡수분광에상응하는분광요소흡수 (8) 정량 reference spectrum database (9) 성분별파장을미리결정 (10) 성분농도미지수 (11) 8+9+10 연립방정식연산 7
FTIR 계측예 CH 4 catalytic reaction spectra FTIR 계측예 CH 4 NO NO 2 8
화학발광법 (Chemiluminescence, CLD) NO + O 3 NO 2 + O 2 NO 2 NO 2 + hν (590-2500 nm) NOx=NO+NO 2 NOx NO 2 NO Ni cat. O 3 NO NO+NO 2 FID(Flame ionization Detector) THC 9
Individual HC 산소자기압력측정법 ΔP = 1/2 H 2. X. C H : 자계의강도, X : 상자성체의자화율, C: 상자성체의농도 10
산소센서및센서출력 Pt, Zr2O3 : 산소농도차검출, 고온상태에서소자의양면이산소농도차가있으면기전력발생 (-) V 배기가스 (+) 대기 다공질 Pt 층 Zr2O3 소자 세라믹코팅층 기전력 V 1 0 rich 산소센서표면의산소농도 lean Stoichiometric 질량분석계 (Mass spectrography) mv 2 /r = Hev H : 자기장세기 (N) V : 양이온속도 (m/s) M : 질량 (kg) e : 전하량 (Coulomb) 양이온을가속전압 v(n/s) 로가속운동에너지는 E K = 1/2 mv 2 = ev 양이온의질량 / 전하량 m/e = H 2 r 2 /(2V) m/e 는 r, H, V 의함수 m/e r, at H,V=const. 11
n-octane 의질량스펙트럼 Gas-Chromatograph 구조 12
Gas-Chromatography(GC) Theory (1) The Separation Process : Sample components are carried the by a mobile phase through a bed of stationary phase. Individual species are retarded by the stationary phase based on various interactions such as surface adsorption, relative solubility and charge. (2) Qualitative Analysis Chromatography is a blind method indicating the presence of a substance but what it is. Qualitative data can be obtained by using the retention data which is characteristics of a substance. Detector produce a response/unit concentration so standards must be used. Column and Detector of GC Column Packed Open(capillary) Bead column porous layer conventional Porous Layer Open Tube Wall Coated Open Tube Detector : Require the high sensitivity, rapid response and large linear range Thermal Conductivity Detector (TCD) : - Change in resistance of a wire based on variations in the thermal conductivity of the gas evolving from a column. - Peak response is a function the TC value for a species so you must standardize for each event of interest. Flame Ionization Detector (FID) - Combustible sample - Production of ions in a flame result in a current that can be measured. - Make-up gas required to maintain an optimum flow-capillary column. 13
TCD(Thermal Conductivity Detector) 휘이트스톤브리지 FID(Flame Ionization Detector) 14
Detector of GC Thermal Conductivity Detector Flame Ionization Detector pa 24 23 22 21 20 19 FID1 A, (KWJ\C-130000.D) Methane ethylene Ethane Propane propylene isobutane n-butane Area: 1.0941 Area: 0.375675 Trans-2-Butene 1-Butene 2,2-dimethylpropane Cis-2-butene 2-methylbutane Area: 8.18799 Area: 3.61275 n-pentane Area: 1.4918Area: Area: 1.37343 1.80732 Inlet of Cat. 1,3-butadiene Area: 5.03987 1-pentene 2,2-dimethylbutane 2-methylpentane Area: 7.68647 Area: 3.17896 n-hexane Area: 2.09559 Area: 1.61893 Ethyl Acetylene Area: 1.37098 Area: 0.70374 2 4 6 8 10 12 FID1 A, (KWJ\C-130005.D) pa 28 26 24 22 20 Methane Ethane ethylene Propane propylene isobutane n-butane Area: 2.95758 Area: Area: 1.20036 1.23162 Area: 0.390169 1-Butene 2,2-dimethylpropane Cis-2-butene 2-methylbutane n-pentane Area: 1.45129 Area: 1.69518 Area: 0.243463 1,3-butadiene 1-pentene 2,2-dimethylbutane Outlet of Cat. 2-methylpentane n-hexane Area: 4.36677 Area: 1.12722 Area: 0.203234 Area: 0.363125 Area: 7.52226 2 4 6 8 10 12 Chromatograms of LIHCs at inlet and outlet of Pd/Rh Catalyst 15
100 80 Conversion(%) 60 40 20 C1 C3 C5 C2 C4 C6 0 100 200 300 400 500-20 Temp( ) Conversion of Light Individual Hydrocarbons on catalyst ECD(Electron Capture Detector) 방사선동위원소자연붕괴 β 입자이용운반기체질소가검출기통과 63Ni 동위원소의붕괴로생성한 β 입자와충돌 이온화 2 차전자발생 à 고정전압으로조정된양극으로이동 à 기준전류 - 운반기체 N 2 + 용질 ( 전자포착 ) 전류감소 ( 량 ) 으로정량화 16
High Performance Liquid-Chromatograph Homework 3 1. 자동차배출가스규제를위한배기계측에서 CVS 법을채택하는이유는? 2. Bear-Lambert 법칙을설명하라. 3. 반도체다이오드레이저분광기의원리와 FTIR 분광분석기의원리의차이점을설명하라. 4. NDIR 분석기의원리를설명하고분석가능한성분을조사하라. 5. CLD 분석기의원리를설명하고분석가능한성분을조사하라. 6. GC 분석기의원리를설명하고분석가능한성분을조사하라. 17