FLEXICOKINGFLEXICOKINGatat

Esso Esso RotterdamRotterdam

06 October 2003

TU Delft

Aad Rooijmans

Esso Nederland BVFlexicokerRotterdam Refinery

Summary

Market demand and crude oil supply Location Flexicoker in refinery flowsheet Conversion : light products out of vacuum residu Flexicoking process description

Reactor Heater Gasifier Coke transfer between vessels

Reliability prevails over the last ton thruput

Market demand and crude oil supply

LPG/Gas

Nafta/Gasoline

Kero/Jet

Diesel

Fuel Oil

44

17

ArabianLight

LPG/GasNafta/GasolineKero/JetDieselFuel Oil

Market demand and crude oil supply

Market demand and crude oil supply

44 4431

1719

24

Arabian Light 1970 1985

LPG/GasNafta/GasolineKero/JetDieselFuel Oil

44 4431 28

1519

24 27

ArabianLight

1970 1985 2005

LPG/GasNafta/GasolineKero/JetDieselFuel Oil

Market demand and crude oil supply

44 4431 28

55

1519

24 27

12

ArabianLight

1970 2005 ArabianHeavy

LPG/GasNafta/GasolineKero/JetDieselFuel Oil

Market demand and crude oil supply

Esso Rotterdam Refinery

GasolineAromaticsLPG Powerformer

APS

VPS

Crude JetDieselHeating oil

LPGNaftaJetDiesel

Flexicoker GasCokes

LPGNaftaJetDiesel

Hydrocracker

to Le Havre

to Antwerp

Vacuum Residue Conversion Processes

Considerations:

z Market demands for light products

z Environmental legislation for cleaner products

z Stricter regulations on refinery emissions

z Vacuum residue contains a lot of carbon and little hydrogenbut also 3-5% sulphur, nitrogen and metals like vanadium and nickel

Vacuum Residue Conversion Processes

Two routes for vacuum residue conversion :

Hydrogen addition processes : Residfining, Hycon high temperature, high hydrogen pressure rapid catalyst deactivation requires large reactors or moving

catalyst sensitive for metal contaminants products do not need any further treating

Carbon rejection by thermal cracking : Delayed Coking, FLUID andFLEXICOKING high temperature, low pressure, no hydrogen no catalyst, abundant coke insensitive to contaminants low refinery SO2 emissions products need after treatment in conventional hydrofiners

Flexicokers

All build 1980 - 1990, investment > 1 billion $$

Rotterdam NL ExxonMobilBaytown USA-Tx ExxonMobilMartinez USA-Ca ShellTOA Japan State-ownedAmuay Venezuela State-owned

Why only 5 Flexicokers in the world ? Initial investment Mechanical cost (mainly in Turnaround) Runlength

FLEXICOKING Process Description

Reactor

Oil is cracked in Reactor and does not travel to Hx or Gx

600 ton fluidized bed of 50 - 300 micron coke particles at 510 - 530C 7 meters diameter, 70 meters high fluidization by steam and product vapors

Reactor is fed at 6 elevations; several feed nozzles per ring

Product yields Gas and LPG 10 - 15 % Naphtha and gasoils 55 - 65 % Coke 25 - 30 %

FLEXICOKING Process Description

Reactor

Heat input via coke transport from heater, 2000 ton/hr, dT= 100 C

Tight temperature control reactor too hot : liquid yield loss due to over cracking reactor too cold : more wall coke or even bogging

Reactor products leave reactor via cyclones to scrubber entrained coke particles are scrubbed with liquid feed in scrubber preheat feed and control FBP heavy gasoil product / recycle

FLEXICOKING Process Description

Reactor

What to watch for during operation ?

Bogging (too low Reactor temperature) Blockage of coke transport to/from heater Coke entrainment / sticky coke High vessel wall temperature Hydrocarbon carry under

FLEXICOKING Process Description

Heater

600 - 630C bed, fluidized by LJG from Gasifier

Cools LJG and transfers heat to cold reactor coke

Temperature fine tuning with a little bit of air

Mechanically complicated vessel many transfer lines and 14 two stage cyclones internal gas distribution/bed support grid exposed to high temperatures quench tee and sugar scoop

FLEXICOKING Process Description

Heater Maintenance ChallengesGrid Can Orifice Erosion

Orifices center caps plug with coke lumps Orifices of outer caps erode in 1 run Replace entire can is quickest repair option Repairs on critical path of site turnaround Splash plates and birdcages Grid redesign idea

FLEXICOKING Process Description

Heater Maintenance ChallengesCarburization of Stainless Steel

All internals stainless steel : 18% Cr/ 8% Ni Temperature range 590 - 635C Gas contains H2, CO and H2S CO reacts with Cr to chromium carbides H2S corrosion of steel due to reduced Cr content Cyclones replaced in last turnaround

FLEXICOKING Process Description

Gasifier

900 - 950 C, 7 meter high fluidized bed, 16 meter diameter

Coke gasification / combustion C + O2 -> CO exo C + H2O -> CO + H2 endo C + CO2 -> 2 CO endo

Gasifies approx. 85-90% of reactor coke production Low Joule Gas contains 50% nitrogen and H2, CO, CO2, H2S and NH3 Temperature control with steam

Coke circulation for heat transfer and prevents too small coke particles

Hot spots

FLEXICOKING Process Description

Coke Transfer lines

Guess how many ? Rx-Hx 3x Hx-Gx 2x Hx-Qx 1x

How can you transfer coke against the pressure ?

Successes and Disappointments over 17 years

Significant (33%) capacity creep at low cost Runlength doubled; reliability is high priority 6 out of 7 runs completed as scheduled

Air Blower problems 1 year after initial start-up Severe fouling in Heater Overhead Exchangers Gasifier Hot Spots Heater maintenance challenges

Reliability and thruput history

Run Ton/hr Days on oil1 202 5912 229 6083 254 5704 258 6845 262 10486 265 10637 269 1195

Reliability and thruput history

Reliability increases effective thruput ! Good process follow-up and stable operation key to success DMC controller installed in 2001 Some hardware changes essential too:

spare heat exchangers, material upgrading, instrumentation upgrading, design changes to reduce turnaround time

Plan for current run is to increased from 3.5 to 4 years

1988-2003 debottlenecks minor Fluid Solids changes 2 new destillation towers replaced a number of pumps diverted LPG from LPG/coker naphtha hydrofiner

Stretch run length with care :Unplanned turnaround has high debits

MEuro contractors ask more money for same scope 1.5 contractors need 14 days to mobilize

result is additional downtime 4 turnaround cost spread over shorter run 3.5 coker down means Pipestill down

jet and diesel to be purchased on spot market 3.5 next run more conservative approach 2.5

total additional cost of unplanned turnaround 15

Partial reactor bog terminated run 2 prematurely

Air Blower problems 1 year after initial start-up

High bearing temperature reading made entire organization nervous

Serious problem or not ? Repair required or do we reach turnaround ? How to operate the coker and rest of the refinery ? How to minimize risk and costs ?

2 day case study chemical + mechanical engineers

FLEXICOKING

Questions ?

FLEXICOKING at Esso RotterdamMarket demand and crude oil supplyMarket demand and crude oil supplyMarket demand and crude oil supplyMarket demand and crude oil supplyMarket demand and crude oil supplyFLEXICOKING Process DescriptionFLEXICOKING Process DescriptionFLEXICOKING Process DescriptionFLEXICOKING Process DescriptionFLEXICOKING Process Description Heater Maintenance ChallengesFLEXICOKING Process Description Heater Maintenance ChallengesFLEXICOKING Process DescriptionFLEXICOKING Process DescriptionSuccesses and Disappointments over 17 yearsReliability and thruput historyReliability and thruput historyUnplanned turnaround has high debitsAir Blower problems 1 year after initial start-upFLEXICOKING