AST Stakeholder Meeting

AST Stakeholder Meeting

California Air Resources BoardStakeholder MeetingFebruary 17, 2005 1927 13th Street, Room 20210:00 a.m. - 12:00 p.m.

AST Stakeholder MeetingAgenda

• Welcome and Introductions • Overview of AP-42 emission estimation approach• Discuss the comments received by stakeholders• Results from small scale studies• Future Plans• Contact Information

AST Stakeholder Meeting

Welcome and Introductions

AST Stakeholder Meeting

Overview of AP-42 Emission Estimation Approach

AP-42 Emission Estimation Approach

• Purpose:

– Use AP-42 approach to calculate statewide emission estimate for Aboveground Storage Tanks (ASTs)

AP-42 Emission Estimation Approach

• Statewide Emission Estimate For ASTs:

– Sum of emissions calculated for 16 regions in CA.– Emissions from each region are calculated based

on the tank size and configuration.

Emissions = Tank Population x Emission Factor

AP-42 Emission Estimation Approach

• Tank Population:

– Number of tanks in a region by size, type, and vapor recovery configuration.

– Determined from a statewide survey of fuel haulers.

AP-42 Emission Estimation Approach

• Survey Status:

– Contacted 187 companies– 62 companies responded– Extrapolated results determined the presence of

approximately 9,300 tanks statewide– Survey portion is completed

AP-42 Emission Estimation Approach

• Emission Factor:

– It is an estimated amount of hydrocarbon emissions emitted into the atmosphere in a given period of time.

– Calculated on a monthly basis.

AP-42 Emission Estimation Approach

• AP-42 Methodology:

– Developed by American Petroleum Institute (API)– Is approved by the U.S. EPA– Widely used by industry– Calculates Total losses/emissions from ASTs

Emissions = Standing Storage or Breathing Loss + Working Loss

– Applies only to tanks vented through small orifices or pressure relief valves.

AP-42 Emission Estimation Approach

• Standing Storage or Breathing Loss (Ls)

– It is a loss due to evaporation. Heating of the tank by the sun causes the fuel to volatilize and vent to the atmosphere.

LS = nVVWVKEKS

– Please review pages 2 - 5 of the AP-42 document

AP-42 Emission Estimation Approach

• Working Loss (Lw) :

– This loss occurs when mass of vapors are emitted to the atmosphere during the:

• Transfer of gasoline from cargo tank to AST (Deliveries)• Transfer of gasoline from AST to vehicle (Dispenses)

Lw = Lw(Deliveries) + Lw(Dispenses)

– Please review pages 6 and 7 of the AP-42 document.

AP-42 Emission Estimation Approach

• Sacramento Case Study

– Used AP-42 methodology to calculate emission factors for 751 - 1000 gallon tank with various configurations.

– Intend to apply this calculation methodology to different tank sizes and configurations for all 16 regions in California.

– Methodology uses reasonable assumptions.

AP-42 Emission Estimation Approach

• Assumptions Used:

– Tank is half full on average.– Fuel surface temperature range is derived from

the ambient temperature range.– Phase I or Phase II vapor recovery controls

• Tanks with controls have a P/V valve at 2” WC • Tanks without controls have no P/V valve

– Working loss emissions assumes 2 deliveries per year and 95% control for both Phase I and Phase II vapor recovery systems.

AP-42 Emission Estimation Approach

Type ofVapor Recovery Standing Working Working Yearly Total Daily Avg.System Loss, LS Loss, LW (Deliveries) Loss, LW (Dispenses) Loss LossNone 218.30 9.07 9.07 236.44 0.65Phase I 197.22 0.45 9.07 206.74 0.57Phase I&II 197.22 0.45 0.45 198.13 0.54

Type ofVapor Recovery Standing Working Working Yearly Total Daily Avg.System Loss, LS Loss, LW (Deliveries) Loss, LW (Dispenses) Loss LossNone 52.42 9.07 9.07 70.56 0.19Phase I 31.35 0.45 9.07 40.87 0.11Phase I&II 31.35 0.45 0.45 32.25 0.09

Insulated Tanks

Total Emissions from Aboveground Storage Tanks (lbs)Using Modified AP- 42 ApproachSacramento, 751-1000 Gallons

Non- Insulated Tanks

Comments Received

• Approach seems reasonable.• Deliveries for some styles of tanks may be

greater than two per year.• Assumption of no P/V valves for tanks with no

Phase I or Phase II controls needs to be investigated.

• Additional comments?

Small Scale Studies(AP-42 Bias)

• How well does AP-42 predict actual emissions from open tanks?– Web search found two AST studies that measured

emissions from open tanks without pressure relief valves.

– ARB performed some initial observations on small one gallon tanks with various vent openings.

Small Scale Studies(Published Literature)

British Coumbia Ministry of Agriculture 38 L 11 L 3

University of Nebraska 34 L 11 L 3

Average 3

Under Estimated by a factor

of

Predicted AP-42 Loss

Publisher Measured Loss

AP-42 Versus Volumetric Loss(Summer Monthly Loss for a 1200 L Tank, No Pressure Relief Valve)

Small Scale Study(ARB Initial Observations)

1/8 Inch 2.5 g 0.43 g 63/8 Inch 7.3 g 0.36 g 20

1 1/2 Inch 36.4 g 0.32 g 114Average 47

Under Estimated

by a Factor of

Predicted AP-42 Loss

Opening Measured Loss

AP-42 Versus Gravimetric Measurement

(16 Degree F Temperature Increase)

Small Scale Study

• Conclusions:– AP-42 method significantly under estimates

emissions on open systems without pressure relief valves.

– Need to refine method to measure emissions from open systems.

Future Plans

• AP-42 Correlation Study on 50 gallon AST• Control Technology Demonstration Using Two

Identical 50 gallon ASTs– One AST will serve as a control.– Second AST will be retrofitted with control

technology.– Emission reductions will be incrementally measured

with a carbon canister.

Need Volunteers• We need volunteers to give us access to

their full size AST, so further correlation studies can be done.

Contact InformationGeneral AST Information• Joe Guerrero (916) 324-9487 - jguerrer@arb.ca.gov

Stephanie Connelly (916) 445-9308 - saconnel@arb.ca.gov

Tank Population• Ranjit Bhullar (916) 322-0223 - rbhullar@arb.ca.gov

LaMar Mitchell (916) 445-9371 - lmitchel@arb.ca.gov

Emission Inventory• Jim Watson (916) 327-1282 - jwatson@arb.ca.gov• Pamela Gupta (916) 324-4458 - pgupta@arb.ca.gov

Contact Information

Need More Information?

• ARB Vapor Recovery Website:– www.arb.ca.gov/vapor/vapor.htm

• ARB Aboveground Storage Tank Website:– www.arb.ca.gov/vapor/ast/ast.htm