Selective Hydrogenation of PyGas over Palladium Catalysts

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1 Selective Hydrogenation of PyGas over Palladium Catalysts S David Jackson Centre for Catalysis Research, Dept of Chemistry, University of Glasgow, Glasgow, UK.

2 Jean-Marc Bader and Gildas Rolland, (Axens), International Petroleum Refining, July 2013

3 Pyrolysis Gasoline by-product of high temperature naphtha cracking, highly unsaturated mixture (carbon range ~C 5 -C 12 ). Typical composition of Pyrolysis Gasoline PyGas Components Weight percent (wt %) Benzene, toluene and xylenes Olefins and dienes Styrene and other aromatics Paraffins and naphthenics

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5 Jean-Marc Bader and Gildas Rolland, (Axens), International Petroleum Refining, July 2013

6 Pyrolysis Gasoline Composition Composition of our model Pyrolysis Gasoline PyGas Components Weight percent (wt %) Toluene Styrene 1-pentene Cyclopentene 1-octene Heptane Decane

7 Reaction Conditions Continuous flow fixed bed reactor Reaction Temperature: 140 C C Hydrogen Pressure : 1-20 barg WHSV: 4 h -1 Catalysts: 16 wt.% Ni/Al 2 O 3 1 wt.% Pd/Al 2 O 3 Catalyst weight: 0.5 g

8 Potential reactions of PyGas 1-Pentene 2-Pentene Cyclopentene Cyclopentane Pentane 2-Octene 1-octene 3-Octene Styrene Ethyl Benzene Ethylcyclohexane 4-Octene Octane Toluene Methycyclohexane

9 2.5E-06 Rate of formation ( r ) Moles g -1 s E E E E-07 Praffins Internal olefins EB Saturated compound from aromatics (MCH, ECH) 0.0E Hydrogen pressure ( P H2 ) barg

10 1 0.8 Yield ( % ) [ MCH ] Toluene(Conv) MCH Time of Reaction ( Hours ) Conv ( % ) [ Toluene ]

11 Carbon Balance Pd/Al 2 O 3 Percent Carbon Balance of each species in synthetic PyGas hydrogenation Reaction Temperature: 140 C C Hydrogen Pressure : 20 bar WHSV: 4 h -1

12 Carbon Balance Pd/Al 2 O 3 Percent Carbon Balance of each species in synthetic PyGas hydrogenation Hydrogen Pressure : 1-20 bar Reaction Temperature: 140 C WHSV: 4 h -1

13 Time FLOW YIELD 100 % 100 % 90% 10%

14 FLOW GC/TPO GC/TPO

15 Pd/Al 2 O 3, WHSV 4h -1, 140C, 5barg H E E 09 Temperature (C) E E E 10 Ion current E E Time (min) Temp CO2 H2O

16 Pd/Al 2 O 3, WHSV 4h -1, 140C, 5barg H 2 Ion Current ( n A) 3.5E E E E E E E 12 78, benzene 92, toluene 104, styrene 106, EB Temperature (C) 0.0E Time ( mins) Temp

17 Pd/alumina, cyclopentene E E-04 Derivative weight (%/C) E E E E-04 Ion current (a.u.) E E Temperature [C] Deriv weight m/e 44

18 Carbon laydown Toluene 0.0E E Ion Current (ma) -2.0E E E Derivaitve Weight (%/oc) E E Temperature (oc) m/e 44 Deriv weight

19 Carbon laydown Toluene 4000 Raman Spectra for Pd/alumina after Toluene Intensity (arb. units) Raman Shift (cm 1 )

20 5 barg H 2 WHSV 4 h Toluene(Conv) MCH 0.8 Conv ( % ) [ Toluene ] Yield ( % ) [ MCH ] Time of Reaction ( Hours ) 0

21 5 barg H 2 WHSV 4 h -1 Yield (%) [ Octane ], Conv (%) [ 1-octene ] octene(Conv) Trans-2-octene Trans-4-octene Octane Cis-2-octene Trans/Cis-3-octene & Cis-4-octene Yield (%) [ Trans/Cis-octenes ] Time of Reaction ( Hours ) 0

22 5 barg H 2 WHSV 8 h octene(Conv) Octane Trans-2-octene Cis-2-octene Trans-3-octene Cis-3-octene Trans-4-octene Cis-4-octene 35 Conv ( % ) [ 1-octene ] Yield ( % ) [ Octane, Trans/Cis-octenes ] Time of Reaction ( Hours ) 0

23 1bargH 2 WHSV 4 h octene(Conv) Octane Trans-2-octene Cis-2-octene Conv ( % ) [ 1-octene ] Trans-3-octene Cis-3-octene Trans-4-octene Cis-4-octene Yield ( % ) [Octane, Trans/Cis-octenes ] Time of Reaction ( Hours )

24 1-alkene reacts at edges/corners 2-alkene reacts on faces

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26 For ring hydrogenation, the ring prefers a flat, parallel adsorption mode rather than an edge-on adsorption

27 Reactions Orders of reactions wrt H 2 Reactants Products P H2 (1-5 barg) P H2 (5-20 barg) 1-pentene Pentane pentene Trans-2-pentene pentene Cis-2-pentene octene Octane octene Trans-2-octene octene Cis-2-octene Cyclopentene Cyclopentane

28 Reactions Orders of reactions wrt H 2 Reactants Products P H2 (1-20 barg) Styrene Ethyl benzene 0.1 P H2 (1-5 barg) P H2 (5-20 barg) Toluene Methylcyclohexane Ethylbenzene Ethylcyclohexane - 2.9

29 Reactants Reactions Products Orders of Reactions wrt PyGas (WHSV PyGas 4-8 h -1 ) P H2 = 5 barg, P T = 20 barg (25% hydrogen gas) P H2 = 10 barg, P T = 20 barg (50% hydrogen gas) 1-pentene Pentane pentene Trans-2-pentene pentene Cis-2-pentene octene Octane octene Trans-2-octene octene Cis-2-octene Cyclopentene Cyclopentane Styrene Ethylbenzene Ethylbenzene Ethylcyclohexane - - Toluene Methylcyclohexane - -

30 Stream cracker plant Hydrogenated PyGas (saturated paraffins + saturated compounds of aromatics) H-PyGas-III PyGas PyGas for aromatics extraction (aromatic + saturated paraffins) H-PyGas-II PyGas for gasoline pool (aromatic + internal olefins) Aromatic H-PyGas-I Gasoline pool

31 H-PyGas-I gives a high octane mixture which can be utilised as a gasoline blending mixture mild reaction parameters [T 140 o C, P T 20 barg, P H2 1-5 barg, WHSV PyGas 4-8 h -1 ]. Reactive species like styrene and alkadienes are selectively hydrogenated. High selectivity to internal olefins No significant hydrogenation of the aromatic compounds.

32 H-PyGas-II gives a feed for aromatics extraction. Uses moderate reaction conditions [T 140 o C, P T 20 barg, WHSV PyGas 4 h -1, P H barg]. Selective hydrogenation of styrene and olefins No hydrogenation of aromatics.

33 H-PyGas-III gives a low aromatic gasoline pool mix. Uses more forcing hydrogenation reaction conditions [P H2 20 barg, P T 20 barg, WHSV PyGas 4 h -1 T o C]. Can be coupled to acid catalyst to get ring opening and iso-alkanes for the production of the high-octane components (iso-alkanes) for the gasoline pool mixture.

34 1-alkene reacts at edges/corners 2-alkene reacts on faces

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37 Acknowledgements Javed Ali Martin MacIntosh Kohat University of Science and Technology (KUST), Kohat, Pakistan

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