HEURTEY PETROCHEMARA 2016

Direct Fired HeatersCritical safety equipment

14/03/16

PART 1 PROCESS OVERVIEW

PROCESS OVERVIEW

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Process heater = direct fired heating equipment used to raise

the temperature of a feed flowing through the coil

Used in various industries

Jamnagar refinery (India) 50 Heurtey’s furnaces in operation

Total petrochemical complex (Belgium) Deok Yang hydrogen unit (South Korea)

REFINING PETROCHEMICAL SYNGAS

PROCESS OVERVIEW

Reheat process fluid without change in phase

HOT OIL FURNACES

CATALYTIC REFORMER

HYDROTREATER/HYDROCRACKER

Reheat a liquid with partial vaporization

COLUMN CHARGE (CDU, VDU, …)

COLUMN REBOILERS

Reheat a fluid with chemical reaction

VISBREAKING

STEAM CRACKER

STEAM REFORMER

EDC CRACKER

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TYPICAL ARRANGEMENT

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Breeching

Arch

Radiant

section

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PART 2 A DANGEROUS EQUIPMENT

LESSONS LEARNED

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Description: Rupture of a tube located in the shock zone due to combined corrosion by Polythionic acids (creating fractures), Oxydation/Sulfuration (reducing the wall thickness) and slow creeping due too very high local wall temperature (coking)

Main Reasons: Lack of local instrumentation (skin thermocouples to detect coking), poordesign resulting in high local heat flux

Acccident: Fire

Consequences: Economical loss and environmental damages

Date: June 26th 2004

Plant: Total Feyzin, Feyzin(France)

Unit: HDS

Heater: Reactor feed heater

Aria : Retour d’expérience sur les accidents technologiques

http://www.aria.developpement-durable.gouv.fr/accident/27459/

LESSONS LEARNED

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Description: The heater was in the process of being restarted and had been operated for several hours with a single burner. As additional burners were lit over a period of severalminutes, insufficient air resulted in oxygen-depleted/fuel rich mixture in the firebox. Subsequent opening of the individual burner air registers was followed by an explosion

Main Reasons: Defficient start-up/operating procedure

Acccident: Explosion & Fire

Consequences: 1 fatality, economicaldamage

Date: November 15th 2013

Plant: Pascagoula Chevron, USA

Unit: Catalytic cracking

Heater: Splitter Reboiler

US Chemical Safety Board (CSB)

www.csb.gov

PART 4 MITIGATING THE RISK

MITIGATING THE RISK OF…

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IMPROPER COMBUSTION

CAUSES CONSEQUENCES DESIGNSAFETY & CONTROL

OPERATION PROCEDURES

LOW/HIGH DRAFTUNSTABLE FLAME

(PULSATING/LIFTING)STACK DESIGN

DRAFT

MEASUREMENT

VISUAL

INSPECTION OF

FLAMES

LOW EXCESS AIRINCOMPLETE

COMBUSTION

BURNER DESIGN

MARGINS

FLUE GAS

ANALYZERS

(O2, CO, UNBURNT)

REDUCE FUEL

BUT DO NOT

INCREASE AIR

FUEL OUTSIDE OF

SPECIFICATION

INSUFFICIENT AIR

SUPPLY

DENSIMETER, WOBBE METER

Charles E Baukal

(2012). John Zink

Hamworthy

Combustion

Handbook

MITIGATING THE RISK OF…

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TUBE RUPTURE

CAUSES CONSEQUENCES DESIGN SAFETY & CONTROL

OPERATION PROCEDURES

FLAME IMPINGEMENT

(BURNER TO TUBES)HIGH LOCAL TEMPERATURE

AND ACCELERATED

DETERIORATION OF TUBES

BURNER

SPECIFICATIONS

TUBE SKIN

THERMOCOUPLES

VISUAL INSPECTION OF

FLAME SHAPES

COKING HIGH LOCAL TEMPERATURE

AND ACCELERATED

DETERIORATION OF TUBES

HEAT FLUX

HEATER GEOMETRY

PROCESS VELOCITY

TUBE SKIN

THERMOCOUPLES

REGULAR VISUAL

INSPECTION OF TUBES

(CHANGING COLOR, QUICK

TUBE SCALING)

CAPACITY EXCEEDING

DESIGN

OVERHEATING OF

TUBES/CAST PIECES AND

ACCELERATED DETERIORATION

FUEL PRESSURE, RADIANT

CHAMBER

TEMPERATURE & PRESSURE

(ESD TRIP)

Charles E Baukal (2012). John Zink

Hamworthy Combustion HandbookCharles E Baukal (2012). John Zink

Hamworthy Combustion Handbook

MITIGATING THE RISK OF…

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TUBE RUPTURE

CAUSES CONSEQUENCES DESIGN SAFETY & CONTROL

OPERATION PROCEDURES

SUPPORTING FAILURE TUBE BOWING AND BREAKING DESIGN MARGINS AND

APPROPRIATE

MATERIAL CHOICE

VISUAL

INSPECTION TO

LOOK FOR CRACKS

CORROSION

(FLUE GAS OR FLUID)ACCELERATED DETERIOTATION

OF TUBES/CAST PIECES

PROPER CHOICE OF

MATERIAL

PROPER DESIGN

TAKING CARE OF ACID

DEW POINT

INSTRUMENTATION & CONTROL

International standards give recommendationsfor instrumentation and control such as:

EN746

API556

NFPA86

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INSTRUMENTATION – MAIN LINE

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INSTRUMENTATION – HEATER

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Draftmeasurement

TTs & PTs linkedto alarm and trip

TSTK Radiant coil

TSTK Shockcoil

O2 & CO analyzers

SAFE START-UP PROCEDURE

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Fuel line leak testing Check tightness of the fuel valves Important to check potential deterioration of the valves

Purging Crucial for removal of possible remaining flammable from radiant chamber

prior to ignition EN746-2 advises to renew the radiant chamber volume 5 times prior to

ignition sequence For natural draft heaters, the atmosphere shall be check with explosimeter

Pilot/Main gas ignition Start on low fuel pressure Pilots must be ignited one by one Pilot flame presence shall be proved by flame detection Only burners whose pilot is lit can then be ignited

Ramp up Heater firing shall be increased slowly 50°C/h to avoid damaging the

refractory and cast pieces Air flow shall be increased prior to fuel flow

PREVENTIVE MAINTENANCE

Casing thermography to identify hot spots and potential failure of refractory. Rapid repair must be done.

Tubes bowing or sagging gives indication of uneven temperature distribution, flame impingement or supporting problem or support failure. Replacement of the defective supports will help ensuring a long lifetime of the coil

Tube external diameter (tape) and thickness (ultrasonic) must be checked at every maintenance turnaround.

Tube skin scaling is the witness of corrosion under high temperature (slow process). If fast corrosion is locally observed, check for flame impingement/inside tube coking.

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Heater & coil thermography

www.Petroval.com

Tube UT

www.Olympus-ims.com

ADEQUAT MAINTENANCE

Burner tips / nozzles and all other surfaces exposed to radiated heat should be checked to be free of carbon, or heat erosion.

Burners must be cleared of debris

Tips alignement must be checked

Burner muffle block should be inspected for general condition and examined to be free of carbon deposit, or any other form of deterioration.

Pipework to be checked for leaks, particularly on flanges joints and connections ("bubble tested" for gas lines).

Instruments should be checked to be operative and if necessary, re-calibrated or replaced.

Increased pressure drop or increase of local skin temperature can be the result of high coking in the coils. Mechanical or steam air decocking to be performed

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Charles E Baukal (2012). John Zink

Hamworthy Combustion Handbook

HEURTEY PETROCHEM CAN HELP

Heater design

checking

Instrumentation

and control

optimization

Refinery staff

training

Furnace

inspection and

field survey

Spare parts

supply