evaporative emission control for gasoline boat fuel systems

Evaporative Emission Control for Gasoline Boat Fuel Systems

Mike Samulski

U.S. Environmental Protection Agency

International Boatbuilders’ Exhibition & Conference

October 20, 2005

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Evaporative Emissions from Boats

Refueling and spillage Diurnal, hot soak, and running loss

Permeation through fuel tank and hoses

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EPA’s Role

Clean Air Act (amended 1990)– section 213 applies to nonroad engines/equipment– “...greatest degree of emission reduction achievable

through the application of technology...”– consider cost, lead time, safety, energy

Past Efforts– implemented exhaust emission standards for the

majority of nonroad engines– evaporative emission standards for some applications

recreational vehicles, Large SI (>25 hp)

– originally proposed evaporative emission standards for marine in August 2002, but have not finalized

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Rulemaking Plans

Scope– exhaust and evaporative emissions– gasoline-powered engines/vessels– build on 2002 NPRM

Schedule– anticipate proposal this spring– final rule ~ 1 year later

Marine Evaporative Emissions– tank permeation– hose permeation– diurnal breathing losses

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Rulemaking Process

gather information meet with stakeholders

Pre-Proposal

NPRM PublicComment

ImplementFRM

public hearing written comment period

publish “Notice of Proposed Rulemaking”

publish “Final Rulemaking”

lead time certification

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Tank Permeation Control

High Density Polyethylene (HDPE)– portable, PWC, and some installed fuel tanks– fluorination, sulfonation, Selar, multi-layer,

alternative materials Cross-Link PE

– installed fuel tanks (low volume production)– barrier coating, multi-layer roto-molding,

alternative materials, alternative constructions Fiberglass

– built-in installed fuel tanks– multi-layer construction

(Metal does not permeate)

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Hose Permeation Control

Multi-layer fuel hose– barriers used today in non-marine applications

(Teflon, THV, FKM, etc.)– marine barrier hose available as well– can add barriers to current marine constructions– > 95% reduction in permeation possible

Evaluating contribution of vapor versus fuel hose

rubber

barrier layer

cover

reinforcement

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Diurnal Breathing Loss Control

Portable fuel tanks– currently have manual seal without pressure relief– could use self sealing caps (1 way valve)

PWC– already have sealed systems with pressure relief valves– 1 psi ~ 50% reduction in-use from an open system

Larger fuel tanks– carbon canister in vent line

> 60% reduction with passive purge negligible back-pressure

– other technologies include bladder fuel tanks active purge canisters

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Other Evaporative Emissions

Venting emissions– running loss, hot soak, effusion– also reduced somewhat by

diurnal control systems

Refueling emissions– vapor displacement– spillage

both air and water pollution issue could be reduced through fuel system design configure fill neck for fuel shut-off before overflow valve to prevent liquid fuel from entering vent line

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Questions?

Mike Samulski

samulski.michael@epa.gov

www.epa.gov/otaq/marinesi.htm