Interim White Paper - Midwest RPO Candidate Control Measures
3/10/2006 Page 7
a preset value, a pressure switch activates a small compressor that draws off excess vapor-laden air. A portion of the hydrocarbon vapors condense and are returned to the tank as a liquid. The remaining hydrocarbons permeate the membrane and are returned to the tank as concentrated vapor. Air, stripped of of the hydrocarbons, is vented. In addition to eliminating hydrocarbon emissions, the unit pays for itself with the value of the recovered gasoline.
Measure SOLV7A – Adopt CARB EVR Stage I requirements. This control measure is based on the use of adoption of the CARB EVR Module 1 requirements that will increase the required control efficiency of Stage I vapor recovery systems from 90 to 98 percent in those counties with existing Stage I requirements. Optionally, the control measures could be extended to counties that currently do not have Stage I requirements.
Measure SOLV7B – Adopt CARB EVR Stage II requirements. This control measure is based on the use of adoption of the CARB EVR Module 2 requirements that will increase the required control efficiency of Stage II vapor recovery systems from 90 to 95 percent in those counties with existing Stage II requirements. Optionally, the control measures could be extended to counties that currently do not have Stage II vapor recovery requirements.
Measure SOLV7C – Require Add-on Control Devices on the UST Vent. This control measure is based on the use of an add-on control device (such as a membrane system, refrigeration unit, or carbon bed) to
reduce vapor nonattainment nonattainment
growth emissions from the UST vent by 90 percent.
It will be applied in all
counties. Optionally, the control measures areas counties in the MRPO region or to all
could be extended to counties counties in the region.
EXPECTED EMISSION REDUCTIONS
We calculated the approximate emission reductions expected from adopting the CARB EVR Stage I requirements and the continued phase-in of ORVR requirements in the following manner:
Obtained 2002 actual emissions from the EPA’s Draft 2002 NEI (Note: the LADCO inventory contained inconsistencies between states and did not have Stage II emissions Ohio);
Increased the Stage I overall reduction from uncontrolled in those counties with existing Stage I requirements from 72% (CE of 90%, RP of 80%) to 78.4% (CARB EVR CE of 98%, RP of 80%); applied a 78.4% (CARB EVR CE of 98%, RP of 80%) in all 8-hour nonattainment counties that do not currently have a Stage I requirement;
Applied an incremental percent reduction for 2009 for ORVR vehicle refueling emissions in all counties using control factors recently developed by E.H. Pechan;
Applied an incremental percent reduction of 50% for Stage II emissions in those counties with existing Stage II requirements (changing CE from existing 90% to 95% required by CARB EVR Module 2) on top of the reductions obtained from ORVR;
Apply a 90 percent reduction to underground storage tank (UST) breathing and emptying emissions.
Current emissions from gasoline distribution facilities and the expected emission reductions from the candidate control measure are summarized in Table 2.
Disclaimer: The control measures identified in this document represent an initial set of possible measures. The Midwest RPO States have not yet determined which measures will be necessary to meet the requirements of the Clean Air Act. As such, the inclusion of a particular measure here should not be interpreted as a commitment or decision by any State to adopt that measure. Other measures will be examined in the near future. Subsequent versions of this document will likely be prepared for evaluation of additional potential control measures.