1) Distillation 2) Conversion ( 전환, 전화 ) 3) Purification
1)Distillation ( 증류 ) 탄화수소의혼합용액인원유를그성분의비점또는휘발도차이를이용 일정한비점범위를가지는성분만으로구성된유분으로분리하는과정 (straight-run run process) 상압증류와감압증류가주로사용됨 가 ) 탈염 (desalting) 원유에는염화물, 황산염이안정한 emulsion 상태로존재 1 ( 염 ) 산- 장치부식 2 석출 ( 고체침전 ) 장치 blocking
micelle: aggregation of surfactant (5~6 nm) CMC: micelle 이형성되는농도 <CMC 를알수있는방법 > Surface tension Conductivity CMC Concentration C CMC Concentration C - 화학탈염범 : 항유화제 (alcohol, 무기화합물 ) 로 emulsion 파괴 - 전기탈염법 : 고압전기장으로 emulsion 파괴 - 효율 : 50 ~ 95%, 염분 > 15 g/1000 lit
나 ) 상압증류 (atmospheric P distillation or topping)
pipe still: pipe 속으로원유가보내져가열압력이걸려있어기화되지않은액상 fractionator: (bubble tower, 증류탑 ) 1 flash zone: 상압에서중질분을제외하고나머지는기화 2 tray zone: 45 ~ 90cm 간격의수십단의 trays ( 기화 / 액화반복 ) reflux: 탑상단온도조절, 증류도향상 stripper: 수증기이용, 다량의용매에용해된저비점유분을분리
유분 b.p ( ) 탄소수용도 gases -161 ~ 0.5 1 ~ 4 LPG, refining fuel 경질 naphtha (light distillate) 중질 naphtha (light distillate) 30 ~ 130 5 ~ 8 석유화학원료 (cracking) blending for gasoline (low ON) 80 ~ 170 7 ~ 12 catalytic reforming (ON 95) 등유 domestic fuel ( 실내등유 ) 150 ~ 280 9 ~ 19 (kerosine) 보일러용, jet fuel, tractor fuel 경유 diesel fuel 230 ~ 350 14 ~ 23 (diesel or gas oil) central heating fuel 잔사유 fuel for power station, ship, large > 350 >17 (residue) heating installation
중유 (heavy y or fuel oil, heavy distillate) 1 잔사유에서 asphalt 제거또는윤활유제조후잔사유등에등유또는경유혼합 2 산업용연료 :Bunker A 소형보일러 / 선박 Bunker B 중형 Bunker C 대형 3 B/C 는대도시사용불가 ( 산업체대형또는발전용 boiler용 )
다 ) 감압증류 (vacuum distillation unit) - 중질유분을고온에서증류하면열분해되어품질과수율이저하 - 가열관내코크스생성 / 부착에따른손상방지 - 감압 : 30~80 mmhg - 고비점유분 1vac. gas oil (VGO) 중질유분해또는 LBO 제조 2 vac. residue (VR) 탈황시설 상압잔사유와고비점유분
감압증류공정
라 ) Steam distillation - 전압을대기압으로유지 - 수증기를불어넣으면탄화수소의분압저하 - 중질유의비점이강하하여 - 낮은온도에서고비점유분유출이가능마 ) Azeotropic distillation 바 ) Extractive ti distillation
2) Conversion ( 전환, 전화 ) 유분을여러방법으로화학적변화를일으켜전보다성능이우수한새로운석유제품을얻는공정가. cracking - gasoline 증산 (Standard Oil, 1912) - cracked gasoline, unsaturated HC 제조나. Reforming - high ON gasoline 제조, aromatics 제조다. Others - isomerization, coking, (de)alkylayion,(de)hydrogenation, hydrotreating 등
가. Cracking - 큰분자에서 C 5 ~C 12 의 (gasoline range) 분자제조 - Saturated HC unsaturated HC (recently) - branched chain and aromatics 형성 (high ON)
가. Cracking ( 계속 ) - 반응 1 cracking of paraffin paraffin + olefin R-CH 2 -CH 2 -CH 2 -R R-CH=CH 2 +CH 3 -R (olefin) (paraffin) 2 dehydrogenation of paraffin R-CH 2 -CH 2 -R R-CH=CH-R + H 2 3 isomerization of paraffin R-CH 2 -CH 2 -CH 3 R-CH-CH 3 CH 3
4 dealkylation of cycloparaffin (in the case of naphthenic HC) +CH=CH 2 =CH-CH 3 CH 2 -CH 2 -CH 3
-process 1 thermal cracking ( 열분해법 ) cracking under high P and T high b.p HC cracked gasolin (gas oil, residue) e) (low b.p) low ON, 안정성문제, 악취 2 visbreaking process (viscosity breaking) 가솔린제조가주목적이아님 ( 열분해의일종, P = 12 ~ 25 kg/cm 2, T ~ 500 o C) AR, VR 의점도저하목적 ( 점도낮은경유등생산 )
3 delayed coking process 감압잔사유, 아스팔트, 열분해찌끼유 불포화화합물多 불안정 4 catalytic cracking ( >35% crude oil) ) largest volume catalytic process 등유이상의고비점유분 high ON gasoline (gasoline 배합 ) Catalysts - 1936 ~ World War II: Houdry clay catalyst - 1950s ~ 60s: synthetic silica-alumina alumina (FB) - since then: riser catalytic unit (zeolite) high T & shorter contact time
Fluidized Catalytic Cracking Process H 2 C 4 gas oil
510 o C Riser Catalytic Cracking Unit 650 ~ 710 o C
5 hydrocracking ( 수소화분해 ) catalytic cracking + hydrogenation purpose: -hydrogenate coke precursor on the catalyst to minimize coke formation and long life of cat. - convert objectionable S-, N-, O- compounds to volatile H 2 S, NH 3 and H 2 O
process - 1930 s: 군사용항공기연료 (Germany / England) (P > 20 MPa uneconomic) - 1959: Standard Oil of California, dual function catalyst (versatility of process) - modern process: to process high content of polycyclic y aromatic compounds * for high ON gasoline (T = 200 ~ 400 o C, P H2 = 1 ~ 10 MPa) - vac. gas oil, deasphalted vac. residue, - heavy gas oil from coking, catalytic cycle oil
mechanism 1thermal cracking (free radical scission) C : C C + C C:H C + H -olefin( 특히ethylene) 다량 - diolefin 비교적많음 -gas(c 1, C 2 ) 대량생성, 방향족은적게생성 - 반응성 : paraffin/olefin > naphthene > aromatics
ex) thermal cracking of n-decane (C 10) )
2 catalytic cracking (ionic fission) C : C C + + C : - C : H C + + H : - - 프로필렌, 부틸렌다량생성 - C 3 ~ C 6 branched (iso-) paraffin - 방향족많고 diolefin 거의없음 - 반응성 : olefin > paraffin ~ naphthene > aromatics
ex) catalytic cracking of n-decane (C 10 ) stable
ex) isomerization by catalytic cracking 1) n-butane
2) n-butylene in the presence of H +
열분해와접촉분해의비교 Thermal Cracking Catalytic Cracking Gas ethylene propylene (C 1, C 2 다량 ) (C 4 paraffin, olefin) more paraffin Main product more olefin than paraffin than olefin 분지지방족다량 ( 특히 C 3 ~ C 6 ) 방향족 적음 많음 코크스 / 타르 석출다량 적음 Diolefin 비교적많음 거의없음
2 visbreaking process (viscosity breaking) - 가솔린제조가주목적이아님 ( 열분해의일종, P = 12 ~ 25 kgf/cm 2, T ~ 500 o C) - AR, VR의점도저하목적 ( 나프타와분해경유소량생산 ) 3 delayed coking process - 감압잔사유, 아스팔트, 열분해찌끼유 - 가스오일이상의경질유와 cokes 부생 - 불포화화합물다량 불안정
정유사정제능력 (2009) SK ( 유공 ) LG-Caltex ( 럭키 Group) 인천정유 ( 한화 Group) S-Oil ( 쌍용정유 ) 현대 Oil Bank ( 현대정유 ) 설립년도 1962.10 1967.05 1968.09 1976.01 1965 가동개시 1964.04 1969.06 1971.06 1980.05 1965.03 공장소재지 울산 여천 인천 온산 부산대산 (1989) 시설능력 ( 천 BPSD) 초기 35 60 50 60 50 2000 810 600 275 443 310 기타사업 내용 석유화학 윤활유 윤활유발전윤활기유윤활유 합작선 ( 철수년도 ) GULF 1980 Caltex - Union Oil 1983 ARAMCO 쌍용양회합작 Shell 1977 시장점유율 39.1 28.7 10.4 12.5 5.8
나. Reforming gasoline range molecules are reconstructed or reformed without change in their C numbers to improve fuel quality (high ON의개질가솔린 ) principal source of aromatic chemicals (BTX) by dehydrogenation of both straight chain and cyclic aliphatics feed stock: a large quantity of straight chain paraffin (15~75%, ON < 50%) and a small amount of branched chain paraffin, naphthene, olefin, and aromatics
Octane Numbers (ON) of Pure Hydrocarbons Paraffins : n-butane 113 n-pentane 62 n-hexane 19 n-heptane 0 n-octane 19 2-Methylhexane 41 2,2-Dimethylpentane 89 223-Trimethylbutane 2,2,3 113 Naphthenes (cycloparaffins) : Methylcyclopentane 107 1,1-Dimethylcyclopentane 96 Cyclohexane 97 Methylcyclohexane 104 Ethylcyclohexane 43 Aromatics : Benzene 99 Toluene 124 1,3-Dimethylbenzene 145 Isopropylbenzene 132 1,3,5-Trimethylbenzene 171 Iso-octane (2,2,4-trimethyl pentane) 100
ON of HC 1동일계HC: b.p낮을수록on (1 pentene 91; 1 hexene 76) 동일탄소수 HC: aromatics > naphthene > olefin > paraffin 2 paraffin: 측쇄가많을수록 ON 3 olefin: 2 중결합이분자중앙에있을수록 ON 4 iso-paraffin > olefin > n-paraffin 5naphthene and aromatics: 측쇄가길수록 ON
Process 1 thermal reforming 경질 olefin 이많은가솔린과다량의가스발생 고분자의 HC가절단되어저분자의탄화수소생성 olefin 중합에따른고비점화합물생성 2 catalytic reforming (1950 UOP) most widely used refinery reaction (1/4 of crude oil in USA)
Reactions 1 isomerization of paraffin to branched chain molecules (iso paraffin) CH 3 n-c 7 H 16 H 3 CCH 2 CH 2 CCH 3 CH 3 2 dehydrocyclization of paraffin to cycloparaffin n-c 7 H 16 CH 3 + H 2 CH 3-3H 2 CH 2 CH 3 n-c 7 H 16 + H 2
3 hydrocracking of paraffin to paraffin n-c 9 H 20 + H 2 n-c 5 H 12 + n-c 4 H 10 4 hydroisomerization of olefin to iso-paraffin CH 3 Heptene-1 + H 2 H 3 CCH 2 CH 2 CH 2 CHCH 3 5 dehydrogenation of naphthenes to aromatics CH 3 CH 3 + 3H 2 (very rapid) CH 3 + 3H 2 (rapid)
6 hydrodealkylation of cyclic hydrocarbons CH 3 CH 3 C 2 H 5 + H 2 + C2H6 CH 3 + CH 3 2 CH 3 7 hydrodesulfurization of S-compounds S CH 3 + 4H 2 C 5 H 12 + H 2 S 8 hydrodenitrogenation of N-compounds + 3H 2 + H 2 + H 2 C 5 H 11 NH 2 C 5 H 12 + NH 3 N N H
Name Formula Structure Representative Heterocyclic Nitrogen Compounds Pyrrole C 4 H 5 N N H Indole C 8 H 7 N N H Carbazole Pyridine C 12 H 9 N 12 9 C 5 H 5 N N H N Quinoline C 9 H 7 N N Isoquinoline C 9 H 7 N N Acridine C 13 H 9 N N
Variation of Sulfur Content of Kuwait Crude Oil Fraction: boiling point range, ( ) Sulfur content, wt% Naphtha: C 4-150 (300) 0.02 Kerosene: 150-230 (300-450) 0.175 Furnace oil: 230-345 (450-650) 1.23 Heavy furnace oil: 345-370 (650-700) 2.37 Heavy gas oil: 350-550 (660-1020) 2.91 Residue: >370 (700) 4.22 Residue: >550 (1020) 5.12
Summary of Catalytic Reforming Hydrogenolysis Cracked products Isoparaffins Dehydrocyclization Isomer ization Isomer ization Alkylcyclopentanes (e.g., Methylcyclopentane) l t ) Isome erization Hydrogenolysis n-paraffins (e.g., n-hexane) Dehydrocyclization Cyclohexanes dual catalyst Dehydrogenation Aromatics (e.g., Benzene)
Catalytic Reformate Production Ratio versus US Chemicals Demand Chemical Reformate Production Chemicals Ratio (%) Demand (%) Benzene 11 56 Toluene 55 10 Xylene 34 34
Composition (wt%) of C 8 Fractions from Catalytic Reforming and Pyrolysis Gasoline Component Catalytic Pyrolysis End-Use Reforming (%) Gasoline (%) Requirement (%) Ethylbenzene 17-22 43-57 p-xylene 16-20 10-12 56 m-xylenes 40-45 23-26 4 o-xylene 17-22 16-19 16 Mixed xylenes (for solvents) 24
다. Other important conversion reactions in refining cracking to olefin and paraffin R-CH 2 -CH 2 CH 2 -R R-CH=CH 2 + CH 3 -R dehydrogenation of paraffin to olefin R-CH 2 -CH 2 R R-CH=CH-R R isomerization of paraffin to iso-paraffin R-CH 2 -CH 2 CH 3 R-CH CH 3 CH 3 or CH 3 H
alkylation by combining olefin with paraffin C C C- C + C= C C C C - - C- C C polymerization by combining low MW olefin C C C C C= C + C= C C-C-C= C-C C C C C C H 2 C- C- C - C- C C iso-octane
hydrotreating 1 to remove impurities 2 to reduce viscosity of heavy residue oil (add H 2 to heavy oil) coking (cokes 생성 ) 1 heavy fraction volatile + cokes 2 reverse of hydrotreating
Variation in S Content
9. 석유정제및전환 Petroleum Fractions Light: Petroleum feedstock Approximate boiling range ( ) Light gasoline < 80 Naphtha (reformer feed) 80-160 Kerosene (jet fuel) 150-230 Gas oil (diesel and heating oil) 170-370 Heavy: Residual oil (fuel oil) > 350
2) Reactions 고가의 H 2 사용, 효율적 ( 불순물처리, 폐기물처리불필요 ) C n H 2n + 2H 2 C n H 2n+2 RS + 3/2H 2 HR + H 2 S RN + 2H 2 HR + NH 3 ROH + H 2 HR + H 2 O (Ex: methyl thiophene and pyridine) CBE 4016