Staff recommend that the Board take the following actions:

1. Adopt proposed amendments to District Regulation 8, Rule 10: Process Vessel Depressurization;
2. Approve a Negative Declaration pursuant to the California Environmental Quality Act (CEQA) for this rule-making activity.

Proposed amendments to District Regulation 8, Rule 10: Process Vessel Depressurization implement control measure SS-17: Improved Process Vessel Depressurization Rule from the 2001 San Francisco Bay Area Ozone Attainment Plan (2001 OAP).   Process vessels in refineries and chemical plants are typically large vessels where organic compounds are fractionated, distilled, chemically reacted, purified or otherwise processed.  As with all process equipment, process vessels must be periodically shut down and emptied for maintenance and repair.   The process of shutting down a unit and depressurizing vessels involves venting vapors to an abatement device.   Rule 10 requires abatement until the partial pressure of hydrocarbons inside the vessel is no more than 1000 mm Hg (4.6 pounds per square inch).   Once the process vessel complies with this requirement, it may be opened and purged with air until the interior is safe for personnel to enter.

Control measure SS-17 in the 2001 OAP calls for abatement of emissions to a more stringent standard than currently required, or abatement until the atmosphere in the interior of the vessel reaches a lower pressure than currently required, or abatement until the hydrocarbon concentration in the vessel reaches a minimal point.   Staff, in development of the proposed amendments, reviewed other district rules and refinery practices and considered similar rules that establish allowable concentration or emission limit standards.   Also, staff formed a workgroup that included representatives from industry, environmental groups, and the California Air Resources Board (CARB).   The workgroup met three times to discuss technical issues and proposals, and staff presented draft language at a workshop in Crockett on the evening of October 28, 2003.

The proposed amendments will supplement the existing control options with a concentration standard and a mass emission limit.  

The proposed amendments to Regulation 8, Rule 10 will:

• Significantly expand the number of process vessels covered by this rule by including all but the smallest of these vessels and make the requirements apply during all vessel depressurizations, not just during refinery turnarounds;
• Retain the internal pressure requirement, but also prohibit process vessels from venting to the atmosphere unless the emissions of organic compounds are reduced to a concentration below 10,000 parts per million (ppm);
• Allow a limited number (no more than 10% over a 5 year period) of vessels that cannot meet the 10,000 ppm limit to be opened to atmosphere, however, limit those vessels to emissions of less than 15 pounds per day;
• Prohibit the opening of vessels that cannot meet the 10,000 ppm limit during Spare the Air days;
• Add two exemptions, for very small vessels and batch processes.   These units were not subject to the previous standards, but became so by the proposed change in the definition of “process vessel”; and
• Add monitoring, recordkeeping and reporting requirements.

In addition, the proposed amendments change, clarify, add definitions, delete obsolete language, add a reference to a test method, and clarify that vessels used in operations subject to other rules, such as paint or pharmaceutical manufacturing, are subject to existing standards in those rules.

To allow regulatory flexibility, the proposed amendments will also allow connections to be placed on the non-repairable list. Connections are solid or flanged fittings that have been subject to the same stringent leak standards as valves since 1998.   Connections may be placed on the non-repairable list for valves at a ratio of one connection for two valves.   This prevents expansion of the total number of components allowed on the list.

 A question was raised at the Board's Stationary Source Committee meeting about process vessel venting during emergency situations.   Regulation 8, Rule 10 addresses planned or anticipated process vessel openings for repair and maintenance.   Unforeseen emissions from emergency situations or unanticipated equipment failures are addressed by District Regulation 1, Section 112: Breakdown.   This section provides relief from any District rule should it be necessary, provided that the emissions were not the result of negligence, disregard or failure to properly maintain equipment.

The proposed amendments fulfill the requirements of control measure SS-17 of the 2001 OAP, and will reduce emissions of organic and other pollutants, including toxic compounds.   Because vessel depressurizations are infrequent events, emissions on an average daily basis are small, however, they may be significant on a given day.   The amended rule will codify best refinery practices and reduce the allowable emissions by approximately 200 pounds per day.   Staff have estimated a total implementation cost of approximately $24,500 per year and a cost effectiveness of approximately $70 per ton of organic compound emissions reduced.   In addition, the socioeconomic analysis prepared for this rule found that there would not be an adverse economic effect on refineries or other industry.

Pursuant to the California Environmental Quality Act (CEQA), the District prepared an initial study to determine the potential environmental impacts of proposed Regulation 8, Rule 10.   The study concluded that the proposed rule would not result in any significant environmental impacts.   No comments on the proposed CEQA negative declaration were received.

Staff suggest two minor changes to the proposed rule to correct an improper cross reference and make a minor editorial change.   In the publicly-noticed rule, Section 8-10-401 requires annual submittal of a report that includes elements required by Section 8-10-502.   This reference should have been to Section 8-10-503.   The proposed change to the reference reflects staff intent as was presented during the rule workshop and as was understood by all parties.   A minor editorial change is proposed for Section 8-10-302.   The revised language is shown in Sections 8-10-302 and 401 of the rule as double strikethrough and double underlined text.   The changes are not significant, and do not require continuation of the public hearing.

  Respectfully submitted,

Jack P. Broadbent
Executive Officer/APCO