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/R Incorporated Providing Environmental Technical Support Since 1989

501 Eastowne Drive, Suite 250  Chapel Hill, North Carolina 27514

Telephone: (919)484-0222  Fax: (919) 484-0122

MEMORANDUM

Date: May 28, 2010

Subject: Site visit report for the PSNC Energy Compressor Station in Ruffin, N.C.

From: Robert Vogt, EC/R Incorporated

Phil Norwood, EC/R Incorporated

To: Bruce Moore, EPA/OAQPS/SPPD/CCG

I. INTRODUCTION

The purpose of this memorandum is to summarize the Environmental Protection Agency 

(EPA) site visit to the Public Service Company of N.C. (PSNC) compressor station in Ruffin, 

North Carolina. 

II. LOCATION AND DATE

PSNC Energy – Ruffin Field Station

Ruffin, North Carolina

February 23, 2010

III. ATTENDEES

PSNC

David Knott, Supervisor, Transmission & Compression, Durham Region

Douglas G. Hobson, AECOM Environmental Project Manager

Robert T. Sievers, Manager, Engineering, System Design

Tucker Bullock, Manager, Operations, Durham Region

U.S. Environmental Protection Agency (EPA)

Alex MacPherson

Bruce Moore

David Salman

Jodi Howard

Nick Parsons

Rachel Agnew

EC/R Incorporated

Heather Brown

Phil Norwood

Robert Vogt
IV. OVERVIEW OF SITE VISIT

The purpose of this visit was to gather information about the PSNC facility and its 

processes, with a focus on the air emissions and equipment, practices and controls that reduce 

these emissions. Prior to the visit, EPA mailed PSNC a letter1 which included an outline of 

information of interest for the site visit. During the site visit, PSNC provided the EPA with 

information in response to this outline (See Attachment 1).

Upon arrival at the site, Mr. Moore provided a summary of the purpose of the visit and 

introductions were made. This was followed by a tour of the facility led by Mr. Sievers. During 

this tour, photographs were taken of facility equipment. These photographs are included as

Attachment 2.

V. SITE AND PROCESSES

PSNC is a wholly owned subsidiary of Scana Energy. The PNSC Ruffin station is a 

natural gas compressor station. It is one of several compressor stations along the pipeline 

between the transcontinental pipeline and the natural gas customers in the Raleigh-Durham, 

North Carolina area. The station, which is an unmanned facility controlled from the PSNC 

office in Gastonia, North Carolina, operates on a seasonal basis.

The PNSC Ruffin station began operations in the early 1960s, and originally housed two 

1200 horsepower natural gas-fired compressor turbines. The facility was renovated between 

2008 and 2009, and the existing compressor turbines were replaced with two electric-start,

Saturn 20-1600 natural gas-fired turbines with a nominal power rating of 1425 hp and a heat 

input of 17.45 MMBtu/hr each.

VI. EMISSION SOURCES, PERMITS, AND REGULATIONS

Air pollutants generated by this facility include PM, NOx , VOC, CO, SO2, and HAPs. 

Detailed emissions data and permit conditions for this facility can be found in the attached North 

Carolina Department of Environment and Natural Resources (NCDENR) Air Quality Permit (see 

Attachment 3). Two natural gas-fired compressor turbines are the most significant emissions 

sources from this facility. Both turbines C3 and C4 are subject to NSPS subpart KKKK, 

Standards of Performance for Stationary Combustion Turbines. This NSPS covers emissions of 

NOx and SO2. 

These turbines have an emission limit of 0.060 lb SO2 per million Btu. This standard is 

met by ensuring that fuel for the turbines meets specified fuel quality characteristics, which is 

verified via tariff sheets.

These turbines have a NOx emission limit of 100 ppm at 15% O2. Compressor C3 was 

tested in July 2008 and had a NOx emission rate of 43.83 ppm, and compressor C4 was tested in 

January 2009 and had a NOx emission rate of 73.73 ppm. The facility has no applicable 

 

1 Letter from Hustvedt, Kent C., Coatings and Chemicals Group, Office of Air Quality Planning and Standards, 

United States Environmental Protection Agency, Research Triangle Park, NC, to Sievers, Robert, Public Service 

Company of North Carolina, Gastonia, NC. Confirmation of Site Visit. February 17, 2010.
emissions limits on CO and PM. The facility does not maintain an integrated LDAR (Leak 

Detection and Repair) program for VOC emissions reduction.

In addition to compressor turbines, a 280 kW natural gas-fired emergency generator is 

located at the facility (Emissions source ID: E-1). This generator is subject to the requirements 

under NSPS subpart JJJJ. The unit was installed prior to January 1, 2009 and is not subject to 

NSPS subpart ZZZZ. The generator is operated once per month on a testing basis.

Insignificant/unpermitted air emissions sources at this facility include compressor station 

blow downs at shutdown, and a 250,000 Btu/hr natural gas-fired heater used to preheat natural 

gas fuel entering the combustion turbine. This small gas heater is not listed in the permit. 

Methane is the primary pollutant emitted by these sources. 

In addition to the routine process operations and emissions, startup and shutdown events 

were also discussed. The facility logged 40 shutdowns of compressor C-3 and 35 shutdowns of 

compressor C-4 over a twelve month period prior to the site visit. PSNC maintains a log of startup and shutdown events. PSNC staff reported that equipment malfunctions were rare, and were 

typically isolated to fail-to-start malfunctions. 

Note: Following the visit, Mr. Sievers confirmed that there was no information discussed during 

the visit that PSNC considered confidential business information (CBI). A copy of this email 

confirmation is included as Attachment 4.