The reasons for revamping heatersare many and include: extendingfired heater working life with

minimum investment; improvingefficiency (eg, increasing duty orefficiency by adding air preheat);reducing environmental impact to meetnoise and flue gas emission regulations,(such as NOx/CO2 reduction) andextending periods between shutdownsthrough improved availability andreliability.

The prolonged use of sulphurousfuels has often resulted in the corrosionof some components essential to theheater’s structural integrity. Where thesulphur compounds in the fuel have

precipitated out behind damagedrefractory layers, it is common for therefractory anchors to have been severelycorroded. This allows the refractory tomove away from the heater walls andthe acidic deposits to attack the steelcasing plate and main supportingcolumns. This frequently results in hotspots on the outer casing of the heater,which can be evidenced by peelingcasing paint or alternately, can bedetected early by using thermal imagingtechnology.

Other common problems that areencountered include:

• Dew point corrosion of cold endsurfaces and tubesheets of air pre-heaters

• Convection section extended surfacetubes clogged by ash, refractories,catalyst fines or unburned fuel,leading to thermal underperformanceof the convection section andsubsequent lower heater efficiency.Where air pre-heaters are installed,this can lead to an increase incombustion air temperature which, inturn, can produce long burner flamesin the radiant section

• Flame impingement on the radiantroof tubes and convection sectiontubes can, in time, cause prematurefailure of the cast tube supports,especially if the supports have alsobeen exposed to fuel contaminantssuch as vanadium and sodium

• Tube thinning and bowing• Damage from tramp air through

heater casing and header boxes.

Almost all heater component parts can and have been replaced onnumerous revamps over the past 40years. Safe, practical and economicsolutions have been delivered forreplacement pressure parts, removal andreinstallation of corroded steelwork, dis-investment of refractories containingasbestos, replacement of combustionequipment and addition of air preheatsystems.

PlanningWhen evaluating revamp projects toestablish their viability, it is wise torecruit the services of a consultantcompany with a proven track record ofactually delivering safe, successful andcost-effective revamps. Such a companywill have experienced heater thermaland mechanical engineers, as well asproject managers, estimators andplanners to undertake a thorough studyof the various possible options availablefor the plant owner to consider.

Intimate knowledge of heater designis essential, as many of the older heaterswere constructed in situ at the site andsafe removal or modification of thecorroded component parts is a skilledtask. Many of these older heaters haveasbestos materials in refractories and/orsealing tapes in joints, which have to beremoved under strict safety proceduresby specialist contractors. Factors such asplot space for lifting, piling for heavylift equipment, logistics for modules,access and egress for plant and heavyequipment, laydown areas and siteworking areas all need to be consideredduring the initial planning andevaluation phase as they will affect cost,schedule and practicality of the varioussolutions.

Another essential ingredient for asuccessful revamp project is the early participation of all relevantpersonnel who will be involved in orimpacted by the proposed work. It is important to involve inspection and safety personnel as well as the usual engineering, operational, andmaintenance groups. During thedefinition of the scope of work, andespecially during the planning, peergroup reviews help reveal any activitiesor requirements hitherto not consideredin the plan. Seemingly unrelatedshutdown activities from otherdepartments can have a crucial impacton the overall plan during shutdown soit is vital to ensure all groups ‘buy in’ tothe project as early as possible and fullydefine the scope of work. Late scopedefinition or significant changes canseverely impact on the shutdownschedule.

Developing options: Cost phase 1When estimating the overall costs andreturn on investment (ROI) of thevarious options under consideration,several aspects should be considered.Lowest in real cost but often the most

Reducing refinery heater revamp costs

The current condition of thousands of fired heaters built since the second half of the 20th century requires urgent attention. This article discusses theimportance of being able to deliver a safe, cost-effective heater revamp, in

the shortest possible shutdown

Tony TindallFoster Wheeler Energy Ltd

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38

When evaluating revampprojects to establish their

viability, it is wise to recruitthe services of a consultant

company with a proventrack record of actually

delivering safe, successfuland cost-effective revamps

Foster Wheeler 6/8/05 12:19 am Page 38

cost-effective overall, is the initial studyand detailed engineering and planning.It is during this phase that comparisonsbetween, say, in situ remedial work andmodular replacement will need to bemade: crucial decisions that will affectthe overall cost of the job. Innovation isessential to effect solutions to problemsthat may seem initially impractical(Figure 1).

Consideration must be given to suchmatters as the strength and integrity ofcorroded structures and the possibleways to handle these safely, or how to establish the presence of any asbestos and the procedures for its saferemoval within the minimum timeavailable. It is often possible to reducethe costs and schedule for dis-investment of materials, such asasbestos, by containing the materialswithin suitably strengthened and sealed modules for later safe disposal away from the immediate plot area. The relatively modestinvestment in thorough detailedengineering and planning made during this stage of the project is more than repaid during the shutdownand construction phase.

Materials, fabrication and logistics: Cost phase 2 The next cost to consider is that ofreplacement materials, off-site pre-shutdown fabrication, transportationand temporary equipment such asheavy lift equipment and manpower forthe shutdown.

The specialist heater contractor who has designed the replacementequipment is best equipped toundertake procurement and supervisionof pre-shutdown fabrication andmaterials to ensure these are availablein advance of the shutdown.

To minimise the possibilities ofoverrun on the shutdown, the bestdefence is good planning. If thecondition of vital components thatmight need replacement before theshutdown cannot be ascertained, or ifthey are at risk from damage during the dis-investment (eg, cast tubesheets), it is worth ‘taking outinsurance’ by replacing them anyway orby having them available. This isespecially wise for long lead itemssuchas pressure parts and castings. If the heater is 30 years old, then thesecomponents have already paid forthemselves anyway! In this phase, closeliaison between the various suppliers,fabricators and on-site shutdowncontractors is essential. Early selectionof contractors and establishment of site rules and conditions is also

critical to success. This is theresponsibility of the projectmanagement team, whether it be theowner themselves or an experiencedmanaging contractor.

The shutdown: Cost phase 3The final phase to consider, theshutdown, is probably the most costlyand often the one most easilyunderestimated. This is especiallyimportant where activities such asremoval of asbestos-type materials isconsidered, as safety will take

precedence over time, and any potentialproblem not carefully considered duringcost phase 1 will invariably extend theshutdown with the possibility that thecost of the project will soar.

While the daily cost of lostproduction and demurrage on salescontracts varies with each refinery, inthe event that the planned shutdown isextended for any reason, these costs canrapidly outweigh the original budgetedengineering and materials cost of therevamp.

Unplanned extended mobilisation ofsite contractors and hire of temporaryequipment such as scaffolding andheavy lift equipment will again drive upthe final cost of the project. The firedheater specialists should be on hand tosupervise the overall site installation, orat least to act as advisors to providespeedy solutions to any unforeseenproblems of the kind that often onlymanifest themselves during the actualshutdown.

Note: This article is based on an articlethat was originally published inHydrocarbon Asia.

Tony Tindall is in business developmentwith Foster Wheeler Energy Limited,Reading, Berkshire, UK.E-mail: tony_tindall@fwuk.fwc.com

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39

Figure 1650-tonne replacementvacuum heater beingmoved onto itspermanent foundationsusing a stainless steel railand sliding pad systemdeveloped by FosterWheeler engineers. Theinstallation, includingdemolition of the existingheater, took just 22 days.

Seemingly unrelatedshutdown activities fromother departments can

have a crucial impact on the overall plan during

shutdown so it is vital toensure all groups ‘buy in’

to the project as early as possible and fully

define the scope of work

Foster Wheeler 6/8/05 12:20 am Page 39