HYDROCARBON PROCESSING GASOLINE COMPONENTS

Transcription

1 HYDROCARBON PROCESSING GASOLINE COMPONENTS English version based on the presentation of Prof. Dr. Jenő Hancsók, D.Sc. held on Vegyészmérnöki- és Folyamatmérnöki Intézet MOL Ásványolaj- és Széntechnológiai Intézeti Tanszék 8200 Veszprém, Egyetem u. 10. Pf Tel.: / Fax.:+36 88/ Pannon University MOL Crude Oil and Coal Technology Department

2 2 Motor gasolines blending components additives

3 3 Motor gasolines Reformate Blending components Isomerate Oligomer gasolines FCC gasoline Hydrocrack gasoline Straight rum gasoline Motor gasolines Alternative components Alkylate Oxygenate Gasolines formed as co-products Additives

4 Light naphtha isomerisation 4

5 Light naphtha isomerisation Light naphtha (~30-40/45-82 C) isomerisation products Light naphtha: C 5 -C 6 hydrocarbons (C7 <2%) or C 5 /C 6 fraction Phenomenon of ismerisation Jenő Hancsók: Hydrocarbon processing, BME, , Copyright 5

6 6 Goal of C 5 /C 6 fraction isomerisation Production of high octane light gasoline fractions (ΔRON: unit) Sometimes pure isopentane production as feed for isopreneproduction

7 Kísérleti oktánszám RON (KOSZ) Jenő Hancsók: Hydrocarbon processing, BME, , Copyright 7 Boiling point-ron correlation of different hydrocarbon types aromások aromatics n-paraffinok n-paraffins többszörös multi-branched elágazású izoparaffinok isoparaffins naftének naphthenes olefinek olefins Forráspont, Boiling point, C C

8 8 Thermodynamics of C 5 /C 6 paraffin isomerisation Paraffin hydrocarbon Reaction heat (25 C), kj/mol from n-pentane 2,2-dimethyl-propane -19,93 2-methyl-butane -8,04 from n-hexane 2,2-dimethyl-butane -18,39 2,3-dimethyl-butane -10,59 2-methyl-pentane -7,12 3-methyl-pentane -4,44

9 9 Equilibrium concentration of pentane and hexane isomers

10 RON Jenő Hancsók: Hydrocarbon processing, BME, , Copyright 10 RON of C 5 and/or C 6 hydrocarbons equilibrium mixtures (open chained) Kísérleti oktánszám C5-paraffinok paraffins C5/C6-paraffinok paraffins C6-paraffinok paraffins Temperature, Hőmérséklet, C C

11 11 Catalysts for C 5 /C 6 paraffin isomerisation Hydroisomerisation catalysts Temperature of favourable activity: High Medium Low 300 C Pt(0,5-0,6)/g-Al 2 O 3 /F F: 3-4% 200 C-300 C Pt(0,3-0,5)/H-Y zeolite Pt(0,3-0,5)/H-Mordenite 200 C Pt(0,3-0,4%)/Al 2 O 3 /chloride (7-10%) Pt/sulphated metal-oxide Mixed metal-oxide

12 12 General mechanism of n-c 5 /n-c 6 paraffins isomerisation on bifunctional catalysts -H 2 Diffúzió Diffusion +H + n-p n-o n-o n-c + fémes hely site Metallic savas hely Acidic site Cracked krakk termékek products +H 2 Diffúzió Diffusion -H + i-p i-o i-o i-c + n-p: n-paraffin; n-o: n-olefin; n-c+:n-carbenium-ion; i-c+: iso-carbenium-ion; i-o: iso-olefin; i-p: iso-paraffin

13 Classification of isomerisation processes According to operation temperature: Low (kb. 200 C) Medium (kb C) High (>300 C) After 1990, only these processes were implemented Jenő Hancsók: Hydrocarbon processing, BME, , Copyright 13

14 14 Adventages of low temperature isomerisation Feed and energy efficiency (CO 2 ) Higher isoparaffin yield Higher RON (2-5 unit) Lower hydrogen consumption (CO 2 )

15 Catalytic reforming 15

16 16 Catalytic reforming Goal: production of high octane blending components and/or production of hydrocarbon mixture suitable for individual aromatics recovery Feed: sulphur free( 1 mg S/kg) straight run and/or hydrocracking and/or other gasoline fractions

17 17 Main reactions I. Dehydrogenation Dehidrogénezés cikloparaffin aromás cycloparaffin aromatic Reaction Hőszínezet heat H= +205 kj/mol + 3 H 2 sűrűség, g/cm 3 0,7694 0,8669 KOSZ: 73,8 119,7 Specific gravity, g/cm3 RON: paraffin olefin H= +90 kj/mol sűrűség, g/cm 3 0,6838 0,7026 KOSZ: 0 89,8 Specific gravity, g/cm3 RON: + H 2

18 18 Main reactions II. Dehydrocyclisation Dehidrociklizáció H= +238 kj/mol + 4 H 2 sűrűség, g/cm 3 0,6838 0,8669 KOSZ: 0 119,7 Specific gravity, g/cm3 RON:

19 19 Main reactions III. Isomerisation Izomerizáció n-paraffin i-paraffin H= -4,4 kj/mol sűrűség, g/cm 3 0,6838 0,6871 KOSZ: 0 52,0 Specific gravity, g/cm3 RON: C5-cikloparaffin cycloparaffin C6 cycloparaffin C6-cikloparaffin sűrűség, g/cm 3 0,7913 0,7694 KOSZ: 100,4 73,8 Specific gravity, g/cm3 RON:

20 20 Side reactions I. Hydrocracking Hidrokrakkolás + H 2 C H 2 C 2 + C 3 + Hydrodealkylation Hidrodezalkilezés + H 2 C 1 +

21 21 Side reactions II. Alkylation Alkilezés + Disproportioning Diszproporcionálódás 2 + Coke Kokszképződés formation

22 22 Volume-yield correlation during different feed (fixed bed process)

23 23 Catalysts for reforming Megnevezés Catalyst Relative Relatív aktivitás activity Króm-oxid Chromium-oxide 1 Molibdén-oxid Molibdenum-oxide 10 Pt/Al 2 O 3 /Cl (1953) (Cl: 0,8-1,3%) Többfémes Multi metallic (1967) (1967) (Pt: 0,2-0,75%- és Re, Sn, Ir, Ge, Rh: 0,01-től 0,3-0,5%-ig) 100 Stabilabb More stable és and more szelektívebb selective

24 24 Process parameters Temperature: C Pressure: 5 20 bar LHSV: 1,5 3,0 m 3 /m 3 h H 2 /hydrocarbon molar ratio: 5:1 12:1

25 Industrial implementation of reforming Reactors number: 3-5 Fixed bed (radial lower pressure drop or axial flow) Moving bed (CCR continuous catalyst regeneration) Construction material: Resistant to reducing and oxidizing atmosphere temperature: 550 C - ig pressure: 5-25(35) bar Jenő Hancsók: Hydrocarbon processing, BME, , Copyright 25

26 26 Conventional (fixed bed) reformer process

27 27 Continuous catalyst regeneration process

28 Product yield structure and characteristics Products Yield, % Characteristics Hydrogen rich gas 7-10 fuel gas (C1-C2) 1-3 propane 3-5 butene 5-8 ~50% i-butane reformate Hydrogen concentration vol% RON: MON: FBP: C higher than the feed aromatic content: >60% specific gravity: 0,76-0,79 g/cm3 Jenő Hancsók: Hydrocarbon processing, BME, , Copyright 28

29 Alkylation 29

30 Chemistry of alkylation Közvetlen Direct processes eljárások C 3 = ic4 + C 4 = C 5 = HF vagy or H2SO4 H 2 4 Szupersavak szilárd hordozókon Indirect Közvetett processes Alkylate Alkilátum C 3 = ic4= + C 4 = + H 2 C 5 = katalizátor* Catalyst* katalizátor** Catalyst** Catalyst*: *katalizátor: phosphorous foszforsav acid szilárd on solid hordozón, support (acidic savas ioncserélő exchange gyanták resins Catalyst**: **katalizátor: olefin olefin hydrogenation hidrogénező (e.g. (pl. Pd/Al2O3, 2 NiMo/Al2O3 O 3, 2 O 3 ) Jenő Hancsók: Hydrocarbon processing, BME, , Copyright 30

31 31 Chemistry of alkylation Reactions: Via tertiary carbenium ion, chain mechanism Initiating step e.g. proton addition onto isobutene in the presence of strong acid C C C C C + H + C C C + Addition step + C C C C + C C C C C C C C C C C + C Chain producing reaction C C C C C C C + + C C C C C C C C C C C C + C C C C + C Chain closing reaction C C C + C C C C C + H + 2,2,4-TMP

32 Thermodynamics of alkylation Exothermic reactions (-630)-(-480) kj/kg alkylate (depending on the olefin) Temperature favouring production of higher octane C 7 -C 8 isoparaffins: ~ 10 C (H 2 SO 4 ) ~ 35 C (HF) Higher temperature polymerisation reaction boiling range increases RON decreases Jenő Hancsók: Hydrocarbon processing, BME, , Copyright 32

33 33 Process parameters of alkylation Parameter HF H 2 SO 4 Solid acid Reactor temperature, C Pressure, bar Isobutane: olefin ratio, vol%/vol% Acid concentration, % Acid in the mixture, % Acid consumption, kg/t alkylate 0,4-0, Main goal: suppress the reaction of olefins with each other

34 34 Products of alkylation Products Isoparaffins with carbon number of the sum of the starting isoparaffin and olefin Premium blending components Aromatic content 0 Olefin < 0,1% Good vapour pressure High RON ( 93) Low sensitivity [ +1 (-) +4 ]

35 35 Product composition and RON/MON of different alkylation process products 100% 80% 60% 40% C 9+ C 8 C 6 -C 7 C 5 20% 0% KOSZ: RON: MOSZ: MON: HF H 2 SO 4 Solid Szilárd acid sav 95,7 94,2 95,6 93,6 97,0 93,2

36 Indirect alkylation 36

37 37 Alkylation and hydrogenation of isobutylene and different butenes: octane number comparison Isobutylene reaction with Isooctane isomer RON MON 1-butene 2,2-dimethyl-hexane 72,0 77,5 1-butene 2,3-dimethyl-hexane 71,3 78,9 2-buttene 2,3,4-trimethyl-pentane 102,5 95,9 2-butene 2,3,3-trimethyl-pentane 106,0 99,4 2-butene 2,2,3-trimethyl-pentane 109,6 99,9 isobutene 2,2,4-trimethy-pentane 100,0 100,0

38 38 Theoretical scheme of process, using acidic ion exchange resin catalyst

39 Oligomerisation 39

40 Oligomerisation Gasoline blending components - dimerisation of propene and/or butenes Jet and diesel blending components - oligomerisation of propene/butene/pentene Petrochemical feedstock - C 7 -C 9 straight chain olefins (alcohol production) - high purity light olefins (e.g. ethylene 1-butene 1-octene) Jenő Hancsók: Hydrocarbon processing, BME, , Copyright 40

41 41 Feedstocks and preconditioning Feedstocks FCC C 3 -C 4 -C 5 olefins thermal cracking (viscosity breaking, delayed coking) light olefins Steam reformer C 3 -C 4 -C 5 olefins Preconditioning Hydrogen-sulphide removal: with amine scrubbing Mercaptans removal: caustic washing Basic materials removal (e.g. ammonia): water washing

42 Mechanism of olefin oligomerisation Via carbenium ion intermedier, which is formed during the reaction of the olefin and strong acid. Proposed dimerisation scheme of propene: Strong acid This intermedier is highly reactive, so it will rapidly react with an other propene molecule, forming a new carbenium ion Proton transmission (to an other propene) Similarly, from butene and propene-butene mixtures first C 7 and C 8 olefins will be formed, later C 9, C 12, C 16 olefins. Jenő Hancsók: Hydrocarbon processing, BME, , Copyright 42

43 43 Thermodynamics of catalytic oligomerisation Exothermic reaction (-920, kj/kg, butene, propene respectively) Necessary to cool the reaction mixture

44 44 Catalysts for oligomerisation Heterogeneous catalytic processes Phosphorous acid on inert support (e.g. SiO 2 ) zeolite Ion exchange resins Homogeneous catalytic processes Nickel and titan-coordination complex + aluminium-alkyl Ion liquids

45 45 Heterogeneous catalytic processes Temperature C Pressure bar

46 46 Scheme of polymerisation gasoline production (on solid catalyst) C 3 = Reactor Reaktor Depropanizer Propánmentesítő Nagynyomású Hűtővíz vízgőz Debutanizer Butánmentesítő Hűtővíz Quench Kvencs C 4 = C 3 = Propene visszavezetés recirculation C = = C C olefin 4 alapanyag feed Kisnyomású vízgőz Kisnyomású vízgőz fejlesztés Kisnyomású vízgőz Polimerysation Polimerbenzin gasoline

47 47 Catalytic polimerisation: yield and quality Feed Value Propene, % 21,4 Butene, % 36,3 Polymerisation gasoline Yield, % 52,9 Specific gravity, g/cm 3 0,735 RON 95,5

48 Oxygenates 48

49 49 Oxygenates Alcohols Ethers

50 50 Ether type gasoline blending components MTBE ETBE TAME Boiling point, C 55,2 71,7 86,1 Ignition point, C Oxygen content, % 18,2 15,7 15,7 RON MON Solubility in water comp. in water, v/v % water in comp., v/v % 4,3 1,4 2,0 0,6 0,6 0,6

51 Isobutene containing hydrocarbon streams Catalytic cracking (15%) Steam cracking (45%) Isobutane dehydrogenation (48%) n-butene isomerisation (17%) Fischer-Tropsch synthesis C 4 fraction (12 20%) ( ) izobutene content Jenő Hancsók: Hydrocarbon processing, BME, , Copyright 51

52 52 MTBE synthesis Catalyst: acidic ion exchange resin CH 3 C CH 3 CH2 + CH 3 OH CH 3 C O CH 3 CH 3 Exothermic, reversible reaction (-37 kj/mol) CH 3 Process parameters methanol/isobutene mol ratio: 1,1-1,2:1 temperature: C in main reaction area, C in the finishing reaction area pressure: 7-20 bar LHSV: 4-6 h -1

53 53 Scheme of the conventional MTBE synthesis

54 54 Ether production

55 Thank you for your attention! 55