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Exhaust ScrubbersWhat you need to know

What are the rules?

The International MaritimeOrganization (IMO) Annex VI of MARPOL 73/78stipulates the regulationsfor exhaust gas emissions(NOx, SOx, PM and CO2). The full text is available atwww.imo.org

The European Commissionhas published Directive2012/33/EU amendingCouncil Directive1999/32/EC as regards thesulphur content of marinefuels. http://eur-lex-europa.eu

Other regulations onemissions reductioninclude EC Directive2005(33), California AirResources Board (CARB),the US EPA, and localjurisdictions such as portadministrations. wwww.ecfr.govwww.arb.ca.gov

In simple terms, ships in IMO-designated Emission Control Areas (ECAs) and SulphurEmission Control Areas (SECAs) can only burn fuel with a sulphur content less than 0.1%mass per mass from January 1, 2015. There is currently a designated ECA around the UScoastline and parts of the Caribbean Sea and a SECA around The North Sea and the Baltic.There is currently a 0.1% limit in EU ports and around the Californian coastline. A global limit of 0.5% will apply to most ship types from 2020.

The IMO MARPOL regulations, the EU regulations and the US EPA regulations are alignedexcept on some points of detail. They all allow for equivalents and so permit the use ofExhaust Gas Cleaning Systems (EGCS), which are called scrubbers. They have to achieve thesame limits on Sulphur Dioxide (SOx) content of the exhaust whatever fuel is burnt as if theship was burning fuel with a sulphur content less than 0.1%. Each scrubber also has to beapproved as an equivalent by the flag administration of the vessel so some different flagstate requirements may apply.

The Californian regulations do not permit such an equivalent.

Exhaust Scrubbers - What you need to know | 1

From January 1, 2015 ships navigating indesignated areas globally will face very tightlimits on how much sulphur can be emittedin the ship’s exhaust. Most shipowners willbe affected and need to make difficultchoices now. The new limits can be met byburning fuel with a lower sulphur content orby fitting an exhaust gas scrubber. There aredifferent regulations in different areas and anumber of scrubber technologies. The decision on whether to fit a scrubber ornot, and which scrubber to fit, is complex. This brochure maps the regulations andchoices which face shipowners and showshow Bureau Veritas can help make the mosteffective choice.

©Wärtsilä

©Wärtsilä

Your choices?

The biggest decision is whether to fit a scrubber or not. It is a trade-off which depends onthe individual economic and operational specifics of each ship and trade. Fit the scrubberand the ship can continue to burn heavy fuel which is usually going to be both cheaper andmore readily available. However fitting a scrubber involves significant capital expenditure,crew training costs and ongoing costs in energy use, maintenance and possibly wasteremoval. Bureau Veritas’ expert teams can make a careful case specific analysis of eachship and trade to guide that crucial decision.

Bureau Veritas can help you with:

The initial analysis of if a scrubber makes sense for their ship and trade or not.The choice of scrubber system.Type approval of a Scheme A system.System and monitoring approval of a Scheme B system.Checking and approving the effect of the ship specific issues.Maintaining class after a retrofit.Maintaining or changing specific environmental notations such as CLEANSHIP.Allocation of a new additional notation EGCS-SCRUBBER.

The full requirements for documentation to be submitted for a scrubber newbuilding orretrofit and the tests required are available online at http://www.veristar.com/wps/portal

Bureau Veritas has the advantage ofwide experience with many differentship types and trades. Scrubbertechnology is in its infancy andexperience in service is limited. Flagstates, port states and equipmentmanufacturers only see part of thepicture. That makes the widerexperience of class extra valuablewhen considering scrubber fitment.

What can Bureau Veritas do to help?

The IMO EGCS guidelines www.egcs.com detail the requirements for the testing, survey,certification and verification of scrubbers to ensure that they will produce emissions levelsequivalent to the fuel sulphur content limits specified and are applicable to all fuel oilmachinery installed onboard ships.The Guidelines provide specific requirements for measuring the sulphur content in theexhaust gas and monitoring wash water discharge quality, including pH changes andcontaminant levels.

There are two compliance options described in the Guidelines:

Scheme A & B are statutory approvals. Class Societies have to provide unit approval aftermanufacturer’s request, approval of ship specific installation, independent verification(Class Type Approval) and verification of performance.

Scheme A

Type Approval: demands asignificant testing and approvalprocess resulting in a Type Approval.

Scheme B

Continuous Emissions Monitoring:requires the use of sophisticatedemissions monitoring equipment.

Note that according to the revised EU Sulphur Directive, ships using alternative emissionabatement methods shall continuously achieve reductions of SOx emissions that are at leastequivalent to the reductions that would be achieved by using compliant marine fuels.According to EMSA, this reference to continuously achieving reduction of SOx emissionsmeans that Scheme A cannot be used in practice. Shipowners whose ships are intended tooperate in European waters have to opt for Scheme B with continuous monitoring of CO2and SOx emissions.

Scheme A and B approval

Exhaust Scrubbers - What you need to know | 32 | Bureau Veritas

©Alfa Laval

©Wärtsilä ©Wärtsilä

Exhaust Gas

Scrubber

The regulations don’t say what a scrubber must be, they simply set the outcomerequirements it must deliver. So owners are free to design and fit their own systems, andequipment manufacturers have come up with a number of different technological solutions.These divide into three main types: open loop; closed loop and dry systems. The IMO regulations also distinguish between two types of approval: Scheme A which is a type approval and Scheme B which is based on continuous monitoring.

What types of scrubber are there?


Exhaust Gas

Exhaust Gas

Exhaust Gas

Circulating sea water pump

Water treatment module Sludge tank

Scrubber

Open loop system

An open loop system uses ambient seawater for exhaust gas scrubbing. The sea water is filtered forheavy metals and particulate matter and then discharged into the sea containing all the sulphurcleaned from the exhaust. These are simpler systems and do not require large amounts of wastestorage and handling on board but there are issues of water intake quality and more importantly someports and areas may not permit the discharge of the waste water containing sulphur.

Closed loop system

A closed loop system uses fresh water that is chemically treated usually by caustic soda injection toeffect scrubbing. Most of the scrubbing agent is re circulated with only minimal water intake andeffluent discharge. These systems avoid the issues of waste water discharge but are more complex,more costly to run, and create waste storage and handling issues on board.A variation on the closed loop system is a hybrid system which can operate as an open loop systemwhile outside special areas.

Water treatmentmodule

Buffer tank


Fresh water loop

Fresh water completion

Sludge tank

Heat exchanger

Na OH

The retrofitting of a scrubber system is complex and includes at least the following workonboard the ship:

Removal of:

Funnel structureDeck platforms and ladderExhaust gas pipes

Installation of:

Deck extension, pillars, ladder and platformsSludge tank (internal structure tank)Fresh water circulation tank (closed loop or hybrid system)NaOH safety measures and tank (closed loop or hybrid system)Scrubber itselfExhaust gas pipes, scrubber water pipesFunnel top structure

How big a job is installation?


Hybrid scrubbers

A combination of closed and open loop scubber in order to offer only the advantages of both solutionsthrough flexibility. It can operate as an open loop system while outside special area.

Exhaust Gas

Scrubber

Exhaust Gas

Water treatmentmodule

Buffer tank


Sea water configuration

Fresh water completion

Sludge tank

Heat exchanger

Na OH

Fresh water configuration

©Wärtsilä ©Alfa Laval


Frequently Asked Questions

How many units will be needed andwhich engines/auxiliaries/boilers willthey serve? What capacity is neededand how will shared scrubbersoperate in different modes? > Contact your engine manufacturerand local Bureau Veritas office forearly acknowledgement of commonscrubber, as Bureau Veritas hasspecific additional requirements forthat typical arrangement.

Knock on effects onexisting systemsand structure Is electrical powersufficient? Isseawater pumpingcapacity sufficient?Will the backpressure on theengines be affected?How will acidiccondensates bedealt with? > This is to be takeninto account at theearliest stage.

Sharing scrubbers Will you have onesystem for all the engines or individualunits? What about the potential backflowof exhaust gas from engines to theexhaust gas duct of another device whichis not in operation? That may pose safetyissues. What about increased backpressure when two or more combustiondevices are combined having differentexhaust gas flow rates, temperatures andpressure? Can the common scrubberoperate effectively at any flow rate over theentire range of exhaust gas of the differentcombinations of the combustion devices?> Contact your local Bureau Veritas office forearly acknowledgement of commonscrubber, as we have specific additionalrequirements for that typical arrangement.

TrainingIs there a need fora specific training?> Crew training forthe safe operationof the scrubber andhandling ofcorrosive chemicalsand waste waterhas to be provided.

Documentation Concerning type approval orapproval under Scheme B, what shall be provided?> Type-approved scrubbers require a specific systemtechnical manual which must meet the requirementsand be carried on board. Scheme B scrubbers do notrequire type approval; instead the monitoringequipment fitted must be approved by theadministration. There has to be a scrubber recordbook or logging system, a record of daily checks onthe monitoring system and each system alsorequires a technical manual in a specific format. AnOn-Board Monitoring Manual is also required foreach scrubber and each ship must have an approvedSOx Emissions Compliance Plan (SECP).

NaOH What is the impact on safety from usingcaustic soda onboard?> Reference Safety Data Sheet is giving the basicrequirement for handling NaOH with care. Thestorage must be carefully addressed, as NaOH isextremely corrosive, so specific appropriate coatingshall be considered for the storage capacity.

SCRs and NOx What about compatibility of SCRs/NOx emissions reduction technologies?> Where an SCR unit is installed to fulfil NOx emission Tier III regulations, compatibilitybetween the scrubber and SCR systems is to be ascertained, especially the temperature atthe scrubber outlet vs. temperature required at the SCR inlet.

Additional requirementsAre there maintenance andinspection additional specificrequirements?> The Planned MaintenanceScheme must be updated tocover the additionalmaintenance and inspectionrequired for exhaust gasscrubbers, pumping systemsand piping. Access to theequipment including inspectionmanholes is to be provided

Redundancy Except where low sulphur fuel oil can be used in case of failure of thescrubber, redundancy must be provided. Is a risk analysis of failure required?> There is no straight requirement for redundancy of scrubbers as this is not a matter of safety,however it is required that the scrubber will have full efficiency within SECA/ECA areas on thefull load range, otherwise an alternative way of fulfilling SOx requirement must be madeavailable onboard. Chech also local regulation such as CARB about the acceptance of scrubberas an alternative to low sulphur fuels.

Retrofitting scrubbers Is there enough space in theengine room casing/funnel to accommodate the exhaustgas scrubber, scrubbing water pumping/piping systemand effluent handling? If installed externally, the increase of the wind surfacearea has to be considered. In case of close loop scrubbersystems, provisions are to be made for the storage anddistribution of caustic soda. What effect does a heavyscrubber installed high in the ship have on the stability,deadweight and heel? Do the materials proposed takeinto account the acidity of the wash water?> Check with your local Bureau Veritas office the initialdesign and new arrangement for compliance with ourRules, specifically on stability, intact and damage. The extra power needed for running the scruber willhave to be taken into consideration, from a consumptionand electric balance point of view.

Specific rulesWhat do the flagadministration and theports to be visited permit? This governs the initialchoice of scrubber system.› Check if the local regulationallows any discharge in Port area or vicinity. Contact your local Bureau Veritasoffice for more information.

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Specific cases Are there any specificinspection and survey?> All the new equipment will be subjectto regular class, flag and port stateinspection and survey.

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Move Forward with Confidence

Bureau Veritas - Marine and Offshore Division67/71, boulevard du Château - 92200 Neuilly-sur-Seine - France

Landline: +33 (0) 1 55 24 73 43 - Mobile: +33 (0) 6 48 69 00 73 [email protected] - www.bureauveritas.com 03

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