Finding Gems in the Rough

Soni O. Oyekan

Reforming & Isom Technologist

Marathon Oil

AIChE MAC William Grimes Award

November 17, 2008

A Simplified Refinery Flow Diagram

NHT Reformer

Gas

Recovery

Sulfur

Plant

FCCU

HC

Coker

Unit

Gasoline

Blending

DHTDistillate

Fuels

Atm

Unit

Vac

Unit

Coke

Asphalt

Fuels

Gasoline

Sulfur

LPG, C3=

Crude

Oil

LSRN

Naphtha Reforming Basics• Operating Goals

– Produce high octane gasoline blending component from low octane naphtha

– Produce hydrogen

– Produce aromatics

• Platinum and Bimetallic Catalysts

– Pt/Al2O3/Cl, Pt/Re/Al2O3/Cl, Pt/Sn/Al2O3/Cl

– Dual functional (hydrogenation/dehydro, acid)

• Hydrotreated Naphtha Feed

– paraffins, naphthenes and aromatics

– carbon range of C6 to C11

• Typical Process Conditions

– 100 to 300 psig, 900 to 1000 F, LHSV 1.0 to 4.0, H2/HC molar ratio of 3 to 8

• Hundreds of Reactions:– dehydrogenation, isomerization, dehydrocyclization,

hydrocracking, hydogenolysis, dehydroalkylation

1977 Assignment & Plan

• First assignment in Exxon was to determine the mode of promotion of Re in Pt/Re catalysis

• Immersed myself as much in understanding fundamental Pt, Pt/Re catalysis and the naphtha reforming process

• Worked on cleaning a Hydrotreating catalyst sulfiding unit for “clean sulfur” platinum/rhenium naphtha reforming studies

• Cleaning with Isopropyl alcohol took about 10 weeks!

• Developed a working network with fundamental researchers and surface characterization specialists, sought out mentors and worked diligently

• Was highly driven, challenged and wanted to succeed

Experimental Program

• Varied rhenium content on a constant Pt catalyst and used Pt and Re only catalysts– 0.3 % Pt, 0.3 % Re, 0.3 %Pt/0.3 %Re, O.3 % Pt/0.6 % Re

• Activated the catalysts in a dedicated unit and characterized catalysts for coke, chloride and sulfur

• Conducted test runs in the a common heater using four separate reactor and product separation systems

• Used same operating conditions and same naphtha feed– 950 F, 175 psig, H2/HC molar ratio of 5

• Completed data work up and compared product yields of C5+, H2 and light gases (C1 – C4)

• Characterized spent catalysts for coke, chloride and sulfur

• Conducted necessary catalyst surface characterizations

• Conducted model compound reforming studies with Heptane and methyl cyclopentane.

A Sample Set of Test Data

Catalyst

(wt. %)

Low Rhenium

0.3 Pt/0.3 Re (A)

High Rhenium

0.3 Pt/0.6 Re (B)

Activity, No 72.0 96.0

C5+ yield, vol. %) 72.0 69.3

• Data indicated 2.7 vol. % lower C5+ yield for B• Lower H2 yield • Higher C1 to C4 gas • Lower coke make• Different C/H ratios for catalyst coke• Sulfur was retained in proportion to Re content• Overall negative catalyst performance data for B• However, data and other factors provided valuable

information for developing a mechanism for rhenium promotion effects

Combo Catalyst Data

Catalyst Low Rhenium

0.3 Pt/0.3 Re (A)

Combo

A Catalyst / B Catalyst

Activity 77.0 92.0

H2 yield, wt. % 2.26 2.31

C1 – C4, wt. % 18.82 17.86

C5+ yield, vol. % 74.3 75.5

• Achieved greater than 1 vol % C5+ yield• About $3+ MM dollars a year for a 40 MBPD Platformer• Introduced new combination Pt/Re catalyst systems• Equi-molar, balanced, skewed, high rhenium terms introduced• Determined that rhenium promoted platinum catalysis via

minimization of steric hindrance for intermediate compounds• Combination Pt/Re catalyst systems now used worldwide• Studies led to 1 US and 9 patents from other countries

Continuous Catalyst Reforming Process

A Major Technology Advancement

• Key objective was getting longer cycle• Note performances of Pt/Sn and Pt were poor• Numerous oil and technology R&D centers discarded poor data

Platinum Catalysis in Naphtha Reforming

72.00

76.00

80.00

84.00

88.00

92.00

96.00

Time

C5+

, V

ol.

%

Pt/Re

Pt

Pt/Sn

UOP & IFP Found Gems In Effective Utilization of

Pt/Sn Catalysts

• UOP decided to capture the high C5+ yield edge of Pt/Sn over Pt and Pt/Re catalyst systems

• UOP introduced Platforming with continuous catalyst regeneration system – CCR Platforming in 1971

• Continuous catalyst regeneration systems required– Spherical catalysts for facile circulation

– A regenerator for coke burn and catalyst activation

• IFP later introduced its version of continuous catalyst regeneration reforming system

• UOP has about 225 units in commercial operations and Axens (IFP) has 60 units.

• Principal catalytic reforming technology in use for petroleum refining

CCRTM Platforming Unit at Marathon Detroit.

Summary

• Soni Oyekan and George Swan of Exxon used “negative” Pt/Re test data to advantage in fixed bed reforming

• I acknowledge the work of George Swan, Bill Baird, Harry Drushel, Chuck Mauldin, Ken Riley and many others for the Exxon work

• UOP used what many oil and technology companies considered “negative” Pt/Sn data to advantage to develop a major CCR reforming technology process

• Axens and UOP have capitalized on licensing CCR technologies to generate hundreds of millions of dollars for their companies.

• In your research studies, critically analyze and look for gems in “negative” data