Catalytic Applications for Enhanced Catalytic Applications for Enhanced

Production of Transportation FuelsProduction of Transportation Fuels

Soni O. OyekanSoni O. OyekanReforming & Isom TechnologistReforming & Isom Technologist

Marathon OilMarathon Oil2009 NOBCCHE Percy L. Julian 2009 NOBCCHE Percy L. Julian

LectureLectureApril 14, 2009April 14, 2009

Lecture OutlineLecture Outline

• Introduction and Acknowledgement• Overview of Oil Refining Processes • Hydroprocessing and Hydrogen • Catalytic Reforming Process• Staged Platinum/Rhenium Catalysts• Two Stage Reduction of Platinum Catalysts• Summary

Introduction & AcknowledgementsIntroduction & Acknowledgements• Dr. Percy L. Julian’s pioneering work that led to

foam, paint, hormones and cortisone• ExxonMobil and Dr George Swan, co-inventor, on

US Patent 4,436,612 and for work on Pt/Re studies in the late 1970s in Baton Rouge, LA

• Engelhard for catalytic reforming work in the 1980s in Edison, NJ

• Marathon for opportunities to apply my expertise to oil refining processes in the past 10 years and support of my professional organization activities

• The catalytic studies were conducted between 1977 and 1984 and the ideas have been incorporated into hundreds of catalytic reformers

Overview of Oil Refining Processes

CRUDE OIL

GASOLINE

DIESEL

ASPHALT

Oil Refiners 6-3-2-1 Crack Spread A Crude Oil Crack Spread = {(Revenue from 3 barrels of

gasoline + 2 barrels of diesel + 1 barrel of asphalt) – (Cost of 6 barrels of crude oil)}/6 3-2-1 Crude Oil Crack Spreads are based on gasoline & diesel only

A Simplified Refinery Flow DiagramA Simplified Refinery Flow Diagram

NHTCatalytic Reformer

Gas Recovery

SulfurPlant

FCCU

H/C

CokerUnit

GasolineBlending

DHTDistillate

Fuels

AtmUnit

VacUnit

Coke

Asphalt

Diesel Fuels

Gasoline

Sulfur

LPG, C3=Hydrogen

CrudeOil

Marathon Garyville CCR Platformer

Hydroprocessing and Hydrogen

A Typical Hydrotreater Flow DiagramA Typical Hydrotreater Flow Diagram

Hydroprocessing ReactionsHydroprocessing Reactions Sulfur, Nitrogen and Oxygenates Removal

– Hydrodesulfurization is the major reaction in hydroprocessing– Hydrodenitrogenation is essential in FCC and hydrocracker feed

pre-treatment– Hydrodeoxygenation is not common, except in the processing of

synthetic (coal, shale) oils and with rerun streams (MTBE, EtOH)

Olefins and Aromatics Saturation– Olefin saturation for product stability and color– Aromatic saturation for solvents, transportation fuels production

and FCC feed pretreatment.

Hydrocracking like FCC is used for conversion of gas oils to gasoline, diesel, heating oil and jet fuel

Hydroprocessing reactions consume significant amounts of hydrogen

Refinery Process HRefinery Process H22 Consumption Consumption

0

500

1000

1500

2000

2500

H2, SCF/B

LSR H/TNHTDHT LPGO H/TDHT HPH/C

H2 consumption is a function of: Process type Feed boiling range Composition Sulfur Nitrogen Metals Oxygenates Unit pressure Unit temperature

Avg. H2 price ~ $4/MSCF

H2 consumption for a 70 MBPD Hydrocracker ~ $220 MM/yr

Catalytic Reforming Processes

Catalytic Naphtha Reforming BasicsCatalytic Naphtha Reforming Basics

• Upgrade the octane of a naphtha feed to produce– High octane gasoline blending component– Hydrogen– Aromatics

• Platinum containing catalysts– Pt/Al2O3/Cl, Pt/Re/Al2O3/Cl, Pt/Sn/Al2O3/Cl

– Dual functionality• Hydrogenation/dehydrogenation• Acidic/isomerization

Catalytic Naphtha Reforming BasicsCatalytic Naphtha Reforming Basics• Hydrotreated Naphtha Feed

– Sulfur < 0.3 wppm– Nitrogen < 0.2 wppm – Metals < 10 ppb– Paraffins, naphthenes and aromatics– Carbon range of C6 to C11

• Typical Process Conditions– 35 to 300 psig, 900 to 1000 F, LHSV 1.0 to 4.0, – H2/HC molar ratio of 1.5 to 6

• Principal Reactions– Naphthenes Dehydrogenation– Naphthenes isomerization– Paraffin dehydrocyclization– Paraffin hydrocracking– Hydrodealkylation of aromatics– Hydogenolysis

Semi Regen & CCR ReformersSemi Regen & CCR Reformers

Platinum/Rhenium CatalysisPlatinum/Rhenium Catalysis• First assignment in Exxon was to determine the

mode of promotion of Rhenium for Pt/Re catalysts• Fundamental Pt/Re catalysis an naphtha reforming

process• Cleaned a 4 reactor Hydrotreating catalyst sulfiding

unit for “clean sulfur” platinum/rhenium naphtha reforming studies

• Isopropyl alcohol was used to clean the unit in 8 weeks!

• 4 reactors shared a common heater• Developed close working relationship with other

Exxon researchers and surface characterization specialists

Catalytic Reforming Reactions Catalytic Reforming Reactions

Paraffin Dehydrocyclization

4H2

Adapted from G. A Mills, H. Heinemann, T. H. Milliken and A. G. Oblad, Ind. Eng. Chem. 45, 134 (1953)

C-C-C-C-C-C-C

+C2H5

C2H5

CH3

Coke

M/A

M/A

A

M

A

M

CH3

M metal sitesA acid site

C2H5

Heptane, 0 RON

Toluene, 120 RON

Staged Platinum/Rhenium Catalysts

Catalyst Test ProgramCatalyst Test Program• Assess rhenium effects at various rhenium concentrations• Make catalysts with varying rhenium content on a constant

Pt catalyst – 0.3 %Pt/0.3 %Re, O.3 % Pt/0.6 % Re, relative Re/Pt ratios– 0.3 % Pt/Al2O3, 0.3 % Re/Al2O3,

• Activate catalysts and characterize for start of run (SOR) coke, chloride and sulfur

• Conduct test runs in a common sand bath heater with four separate reactor and product separation systems

• Use the same operating conditions and naphtha feed– 935 F, 200 psig, 5000 SCF/B H2/HC

• Obtain C5+, H2 and light gases (C1 – C4) yields• Characterize spent catalysts for coke, chloride and sulfur• Conduct model compound reforming studies with Heptane

and methyl cyclopentane.

Isothermal Unit Evaluation of Pt/Re Isothermal Unit Evaluation of Pt/Re CatalystsCatalysts

Rel Re

C5+, vol. %

Catalyst Activity

EOR Coke

EOR Sulfur

1.0 70.8 85.0 8.4 0.03

1.5 71.2 83.0 9.2 0.05

2.0 70.7 81.0 8.5 0.07

2.7 70.3 95.0 7.3 0.12

3.9 69.9 109.0 7.3 0.14

Test Summary Lower coke make with higher Rhenium Lower C5+ and H2 yields Higher sulfur retention Higher activities with Rhenium content Different H/C ratios for the coke Shift in aromatics to BTX

Feed: P, 69.1 vol. %; N + A, 30.9, vol. %

Process Conditions;935 F, 200 psig, H2 rate of 5000 SCF/B

Rel. Re = wt % Re/wt % Pt in catalyst

Commercial Simulation Unit DataCommercial Simulation Unit Data

Catalyst Cat A Cat B Delta

Activity, No

72.0 96.0 +24

C5+, vol. %

72.0 69.3 -2.7

Cat A 0.3 % Pt/0.3 % ReCat B 0.3 % Pt/0.6 % Re

Cat B = Rel 2

Feed: Light Arabian Naphtha

Process Conditions:950 F, 175 psig, 3000 SCF/B, 102 RON

Test Summary• 2.7 vol. % lower C5+ for B • Lower H2 yield • Higher C1 to C4 gas • Lower coke make

Combination/Staged Catalyst DataCombination/Staged Catalyst DataCatalyst Low Rhenium

0.3 Pt/0.3 Re (A)CombinationCatalyst A & Catalyst B

Delta

Activity 77.0 92.0 +15

H2 yield, wt. % 2.26 2.31 +0.05

C1 – C4, wt. % 18.82 17.86 -0.96

C5+ yield, vol. % 74.30 75.50 +1.2

• Production gains for C5+ (gasoline) and H2 • $5+ MM dollars a year for a 40 MBPD Platformer• Introduced staged Pt/Re catalyst systems based on Rel. Re• Combination Pt/Re catalyst systems are now used worldwide• Determined that rhenium promoted platinum catalysis via minimization of steric hindrance for intermediate compounds• Studies led to KX-160, US Patent 4,436,612 & other 8 patents

Paraffin Dehydrocyclization

4H2

Rhenium modifies sterically hindered intermediate compounds

C-C-C-C-C-C-C-C-C

+C4H9

C4H9

C4H9

C3H7

COKE

M/A M

A

M

A

M

, X

M metal sitesA acid site

Where X is CH3, or C2H5

Two Stage Reduction of Platinum Catalysts

Reforming Catalyst ReactivationReforming Catalyst Reactivation

• Burn coke off spent catalyst– CXHy + (x+y/4) O2 xCO2 + (y/2)H20

• Re-disperse agglomerated platinum and promoter metal sites

• Reduce platinum and promoter– Manage water evolution– Manage reactions with hydrocarbons – Optimize reduction of platinum and promoter – Manage catalyst chloride loss

• Sulfide Pt/Re catalysts to temper hyperactive sites

Platinum & Rhenium ReductionPlatinum & Rhenium Reduction

Past work had shown the following:

• Platinum is reduced at 600 F• Rhenium reduction is not facile and requires temperatures > 1100 F

Scelza et. al: TPR work shown here

Hypothesis:Use reduced Platinum to catalyze the reduction of rhenium oxide or a promotermetal oxide

PtO2 + 2H2 Pt + 2H2O

Re2O7 + 7H2 2Re + 7H2O

Two Stage ReductionTwo Stage ReductionEnhances Gasoline and H2 YieldsEnhances Gasoline and H2 Yields

Standard Red.

2 Stage Red.

Delta

H2, wt. % 2.44 2.52 +0.08

C1, wt. % 1.27 1.18 -0.09

C2, wt. % 1.81 1.65 -0.16

C3+C4, wt. %

6.87 5.63 -1.24

C5+, vol. % 82.54 83.77 +1.23

Novel activation involves:US Patent 4,539,307

(1)Reduction at a temp between 600 F and 750 F(2)Nitrogen purge to remove water(3)Another reduction at temp between 900 F and 1000 F

Feed: P/N/A 46.9/37.0/16.1Process conditions: WHSV 4 200 psig, H2/HC 3, 98 RON

SummarySummary

• Pt/Re catalysis work by Soni Oyekan and George Swan of Exxon led to increased production of hydrogen and gasoline blending components for oil refiners

• The Pt/Re studies led to use of terms such as equi-molar, balanced, unbalanced and skewed by technology providers and oil refiners

• Two stage reduction of platinum containing catalysts is now used worldwide in over 120 high performance catalytic reformers

• Platinum catalyst inventions have led to enhanced economic benefits for oil refiners through increased production of hydrogen, gasoline, diesel and jet fuel

• Other catalytic reforming process contributions led a better assessment of the impact of feed sulfur for platinum containing catalysts

Thank You For Your Time2005 Marathon Garyville Refinery