SRI/USEPA-GHG-VR-08
September 2000
Environmental Technology
Verification Report
C. Lee Cook Division, Dover Resources, Inc.
Static-Pac™ System
Phase II Report
Prepared by:
Southern Research Institute
Under a Cooperative Agreement With
SERA U.S. Environmental Protection Agency
ElVetVetV
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EPA REVIEW NOTICE
This report has been peer and administratively reviewed by the U.S. Environmental Protection Agency,
and approved for publication. Mention of trade names or commercial products does not constitute
endorsement or recommendation for use.
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SRI/U SEP A-GHG-VR-08
September 2000
Greenhouse Gas Technology Verification Center
A U.S. EPA Sponsored Environmental Technology Verification Organization
C. Lee Cook Division, Dover Resources, Inc.
Static-Pac™ System
Phase II
Technology Verification Report
Prepared By:
Southern Research Institute
Greenhouse Gas Technology Verification Center
PO Box 13825
Research Triangle Park, NC 27709 USA
Under EPA Cooperative Agreement CR 826311-01-0
U.S. Environmental Protection Agency
Office of Research and Development
National Risk Management Research Laboratory
Air Pollution Prevention and Control Division
Research Triangle Park, NC 27711 USA
EPA Project Officer: David A. Kirchgessner
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TABLE OF CONTENTS
Page
ACKNOWLEDGMENTS iv
1.0 INTRODUCTION 1-1
1.1 BACKGROUND 1-1
1.2 THE STATIC-PAC TECHNOLOGY 1-2
1.3 VERIFICATION GOALS 1-6
2.0 TECHNICAL BACKGROUND AND VERIFICATION APPROACH 2-1
2.1 METHANE EMISSIONS FROM NATURAL GAS COMPRESSORS 2-1
2.2 DESCRIPTION OF THE TEST SITE AND STATIC-PAC INSTALLATION 2-2
2.3 VERIFICATION APPROACH 2-2
2.3.1 Determining Gas Savings and Payback 2-3
2.3.1.1 Case 1 2-4
2.3.1.2 Case 2 2-5
2.3.1.3 Impact on Normal Running Emissions 2-7
2.3.1.4 Annual Gas Savings and Payback Period 2-7
2.3.2 Emission Measurements and Calculations 2-9
2.3.2.1 Rod Leak Rate Measurements 2-10
2.3.2.2 Component Leak Rate Measurements 2-12
2.3.2.3 Natural Gas Composition Measurements 2-13
2.3.2.4 Blowdown Volume Determination 2-13
2.3.3 Engine Operational Data 2-13
3.0 RESULTS 3-1
3.1 ROD PACKING KYIISSIONS 3-1
3.1.1 Emissions During Idle/Shutdown 3-1
3.1.2 Emissions During Compressor Operation 3-4
3.2 OTIIKR EMISSION SOURCES 3-8
3.2.1 Valve Leaks and Blowdown Volume 3-8
3.2.2 Miscellaneous Fugitive Sources 3-8
3.3 NET GAS SAVINGS 3-10
3.3.1 Compressor Operational Characteristics 3-10
3.3.2 Case 1 and Case 2 Gas Savings During the Verification Period 3-10
3.4 ANNUAL GAS SAVINGS 3-13
3.4.1 Annual Case 1 and Case 2 Gas Savings 3-13
3.4.2 Estimated Annual Gas Savings For Other Compressors and Engines 3-15
3.5 STATIC-PAC PAYBACK PERIOD 3-17
3.5.1 Capital, Installation, and Operation and Maintenance Costs 3-17
3.5.2 Payback Period for the Test Engines 3-19
3.5.3 Payback Period for Other Compressors and Engines 3-20
3.5.4 Limitations to the Verification Conclusions 3-21
4.0 DATA QUALITY 4-1
4.1 BACKGROUND 4-1
4.2 ROD PACKING EMISSION RATE MEASUREMENTS 4-1
4.2.1 Unit Valve, Blowdown Valve, and Pressure Relief Valve 4-6
4.2.2 Gas Composition 4-8
4.2.3 Blowdown Volume 4-9
4.3 OVERALL UNCERTAINTY IN THE MEASUREMENTS, NET GAS
SAVINGS, AND METHANE EMISSIONS VALUES 4-9
5.0 REFERENCES 5-1
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APPENDICES
Page
APPENDIX A Example Payback Calculations For Case 1 A-l
APPENDIX B Engine Operating Schedule for Phases I and II B-l
APPENDIX C Static-Pac Operator's Manual - Automatic Control System C-l
LIST OF FIGURES
Page
Figure 1-1 Schematic of a Gas Compressor Engine and Rod Packing 1-3
Figure 1-2 Rod Packing Cutaway with Static-Pac 1-4
Figure 1-3 Static-Pac Actuation and Deactuation Process 1-5
Figure 2-1 Compressor/Engine Configuration and Emissions Sources 2-6
Figure 2-2 Flow Tube Calibration - Vane Anemometer (12/10/99) 2-11
Figure 3-1 Static-Pac Performance Over Time 3-4
Figure 3-2 Operating Emissions 3-5
Figure 3-3 Emission Reduction Performance at Varying Rod Leak Rates 3-16
Figure 4-1 Flow Tube Calibration - Vane Anemometer 4-4
Figure 4-2 Flow Tube Calibration - Thermal Anemometer 4-4
Figure 4-3 Compressor Rod Emissions Data 4-5
Figure 4-4 Emission Reduction Determinations for Static-Pacs 4-6
Figure 4-5 Flow Tube Calibration - Vane Anemometer at High Flows 4-8
LIST OF TABLES
Page
Table 2-1 Common Shutdown Scenarios and Emissions 2-4
Table 2-2 Anemometer Range of Detection in Flow Tube 2-10
Table 3-1 Rod Seal Leak Rate (Units Idle and Pressurized) 3-2
Table 3-2a Rod Packing Leak Rates, Engine 801 - Operating 3-6
Table 3-2b Rod Packing Leak Rates, Engine 802 - Operating 3-7
Table 3-3 Component Leak Rates 3-9
Table 3-4 Average Leak Rates Used to Compute Gas Savings 3-11
Table 3-5a Case 1 Gas Savings for the Test Period 3-12
Table 3-5b Case 2 Gas Savings 3-12
Table 3-6 Operating and Idle Hours for Engines 801 and 802 - 1999/2000 3-13
Table 3-7a Annual Gas Savings for Case 1 (February 1999 to January 2000) 3-14
Table 3-7b Annual Gas Savings for Case 2 (February 1999 to January 2000) 3-14
Table 3-8 Case 1 Annual Gas Savings Matrix for Varying Rod Leak Rates
and Engine Idle Periods 3-17
Table 3-9a Static-Pac Equipment and Installation Costs 3-18
Table 3-9b Summary of Findings for Static-Pac Operation and
Maintenance Costs 3-19
Table 3-10 Case 1 Payback Period Matrix 3-20
Table 4-1 Data Quality Indicator Goals 4-2
Table 4-2 Summary of Flow Tube Calibrations (Low Flows) 4-3
Table 4-3 Summary of Flow Tube Calibrations (High Flows) 4-7
Table 4-4 Summary of Errors Associated With Key Measurement Variables 4-10
Table 4-5 Error Propagation and Overall Measurement Uncertainty 4-10
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ACKNOWLEDGMENTS
The Greenhouse Gas Technology Verification Center wishes to thank the following staff of ANR Pipeline
Company for their invaluable service in hosting this test: Curtis Pedersen, Dwight Chutz, Marilyn
Wenzel, and Ron Sander. They provided the compressor station to test this technology, gave technical
support during the installation and shakedown of the technology, and provided key station operating data.
Thanks are also extended to Gary Swan of CMS Panhandle Eastern Pipeline Company, and to the
Center's Oil and Natural Gas Industry Stakeholder Group for reviewing and providing input on our
testing strategy and this report.
IV
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1.0 INTRODUCTION
1.1 BACKGROUND
The U.S. Environmental Protection Agency's Office of Research and Development (EPA-ORD)
operates a program to facilitate the deployment of innovative technologies through performance
verification and information dissemination. The goal of the Environmental Technology
Verification (ETV) program is to further environmental protection by substantially accelerating
the acceptance and use of improved and innovative environmental technologies. The ETV
program is funded by Congress in response to the belief that there are many viable environmental
technologies that are not being used for the lack of credible third-party performance data. With
performance data developed under this program, technology buyers, financiers, and permitters in
the United States and abroad will be better equipped to make informed decisions regarding
environmental technology purchase and use.
The Greenhouse Gas Technology Verification Center (the Center) is one of 12 independent
verification organizations operating under the ETV program. The Center is managed by EPA's
partner verification organization, Southern Research Institute (SRI), and conducts verification
testing of promising GHG mitigation and monitoring technologies. This Center's verification
process consists of developing verification protocols, conducting field tests, collecting and
interpreting field and other data, obtaining independent peer review input, and reporting findings.
Performance evaluations are conducted according to externally reviewed Verification Test Plans
and established protocols for quality assurance.
The Center is guided by volunteer groups of Stakeholders. These Stakeholders offer advice on
specific technologies most appropriate for testing, help disseminate results, and review test plans
and verification reports. The Center's Executive Stakeholder group consists of national and
international experts in the areas of climate science, and environmental policy, technology, and
regulation. It also includes industry trade organizations, environmental technology finance
groups, various governmental organizations, and other interested groups. The Executive
Stakeholder Group helps identify and select technology areas for verification. For example, the
oil and gas industry was one of the first areas recommended by the Executive Stakeholder Group
as having a need for high quality performance verification.
To pursue verification testing in the oil and gas industries, the Center established an Oil and Gas
Industry Stakeholder Group. The group consists of representatives from the production,
transmission, and storage sectors. It also includes technology vendors, technology service
providers, environmental regulatory groups, and other government and non-government
organizations. This group has voiced support for the Center's mission, identified a need for
independent third-party verification, prioritized specific technologies for testing, and identified
broadly acceptable verification strategies. They also indicated that technologies that reduce
methane leaks from compressor rod packing are of great interest to technology purchasers. In the
natural gas industry, interstate gas pipeline operators use large gas-fired engines to provide the
mechanical energy needed to drive pipeline gas compressors. In the U.S., fugitive natural gas
leaks from these compressors represent a major source of methane emissions, and a loss of
economic and natural resources.
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To pursue verification testing on compressor rod packing technologies, the Center placed formal
announcements in the Commerce Business Daily and industry trade journals to invite vendors of
commercial products to participate in independent testing. C. Lee Cook Division of the Dover
Resources, Inc. responded, and committed to participate in a medium-term independent
verification of their static sealing technology. The technology is referred to as the Static-Pac™
and is designed to reduce methane leaks from compressor rod seals during periods when the
compressor is in a standby and pressurized state.
Performance testing of the Static-Pac was carried out at a compressor station operated by ANR
Pipeline Company (ANR) of Detroit, Michigan. The verification test was planned to be executed
in two phases where: Phase I evaluates short-term gas savings and documents installation costs;
and Phase II addresses additional performance parameters including medium-term technical and
economic performance factors. The Phase I performance results are documented in a separate
report titled Environmental Technology Verification Report for the C. Lee Cook Division, Dover
Corporation Static-Pac™ System - Phase I (SRI 1999/ The Phase I report may be downloaded
from the Center's Web site at www.sri-rtp.com. This report presents the results of the Phase II
test, using data collected during both phases of testing spanning the period of July 15, 1999 to
January 24, 2000.
Details on Phase I and II verification test design, measurement test procedures, and Quality
Assurance/Quality Control (QA/QC) procedures can be found in the Testing and Quality
Assurance Plan for the C. Lee Cook Division, Dover Corporation Static-Pac™ System (SRI
1999/ It can be downloaded from the Center's Web site. The Test Plan describes the rationale
for the experimental design, the testing and instrument calibration procedures planned for use,
and specific QA/QC goals and procedures. The plan was reviewed and revised based on
comments received from C. Lee Cook, ANR Pipeline, selected members of the Oil and Gas
Industry Stakeholder Group, and the EPA Quality Assurance Team. The plan meets the
requirements of the Center's Quality Management Plan (QMP), and conforms to EPA's standard
for environmental testing. In some cases, deviations from the Test Plan were required. These
deviations, and the alternative procedures selected for use, are discussed in this report.
The remainder of this section describes the Static-Pac technology and the goals of the
verification. Section 2 describes methane emissions from natural gas compressors, and describes
the test site and measurement system employed. Section 3 presents Phase II test results, and
Section 4 assesses the quality of the data obtained.
1.2 THE STATIC-PAC TECHNOLOGY
One of the largest sources of fugitive natural gas emissions from compressor operations is the
continuous leakage associated with operating and idle-mode compressor rod packing. When a
compressor is in standby mode, natural gas can leak into the atmosphere from the packing case
and other compressor emission sources. Based on an EPA/GRI study, reciprocating compressors
in the gas transmission sector were operating 45 percent of the time in 1992, but were in standby
or off-line mode for the remaining 55 percent (Hummel et al., 1996). If rod leaks during standby
operations are reduced or eliminated, significant gas savings and emissions reductions could
occur. The C. Lee Cook Static-Pac device is intended to provide this benefit.
In general, compressor packing provides a seal around the rod shaft, keeping high-pressure gas
contained in the compressor from leaking out into the atmosphere. A typical compressor packing
case is shown in Figure 1-1 (location No. 3). It consists of one or more sealing rings contained
within a case that serves several functions. These functions include: lubrication, venting,
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purging, cooling, temperature and pressure measurement, leakage measurement, rod position
detection, and on occasion, sealing for standby mode operations (GRI 1997). In conventional
packing, the sealing rings are configured in series to successively restrict the flow of gas into the
distance piece between the compressor and the engine. The sealing rings are held in separate
grooves or "cups" within the packing case, and are free to move laterally along with the rod and
"float" within the grooves. The distance piece, shown between locations 3 and 4 in Figure 1-1, is
sealed and typically vents rod packing leaks to the atmosphere.
Location of
Breaker Ring
Compressor
Engine
Compressor
Rod
Distance Piece
1 Compressor Valves and Unloaders
2 Piston & Rider Rings
3 Packing Rings & Case
4 Oil Wiper Rings & Cases
A conventional packing case usually contains seven to nine cups. Each cup houses one or more
seal rings, which restrict the flow of natural gas into the distance piece. Each ring seals against
the piston rod and also against the face of the packing cup. The first cup is occupied by the
breaker ring (Figure 1-1), designed to reduce the pressure on the packing rings by providing an
orifice restriction to flow. A second function of the breaker ring is to regulate the reverse flow of
gas from the packing case into the cylinder. This reverse flow occurs as the piston begins the
intake stroke, and the pressure is rapidly reduced in the cylinder.
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The remaining cups are occupied by conventional three-ring packing sets which consist of a
radial cut ring, a tangent cut ring, and a backup ring and are designed to reduce the amount of gas
leaking from the compressor into the distance piece. The final cup houses a vent control ring
which can be used to transport the leaking gas for subsequent use or discharge into the distance
piece. A detailed description of rod packing is given in GRI's report documenting existing
compressor rod packing technology and emissions (GRI 1997).
During idle periods on units that remain pressurized, rod packing leaks usually continue when the
rod motion has stopped. The leakage encountered during idle periods can be due to the loss of
lubrication oil which normally fills the leak paths, changes in the shape of the ring as it cools, and
changes in rod alignment as the temperature changes (GRI 1997).
The Static-Pac is a gas leak containment device designed to prevent rod packing leaks from
escaping into the atmosphere during compressor shutdown periods. The Static-Pac system is
installed in a conventional packing case by typically replacing two cups in the low-pressure side
of the packing case (Figure 1-3). When the compressor shuts down, an automatic actuation valve
is opened, admitting pressurized gas behind the internal piston. As shown in Figures 1-2 and 1-3,
the movement of the piston wedges a lip seal into contact with the rod. When the actuating
pressure is lowered during compressor startup, the piston retracts, causing the Static-Pac seal to
lift from the rod surface.
Figure 1-2. Rod Packing Cutaway with Static-Pac
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1-4
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To allow room for the addition of the Static-Pac, a packing case with the Static-Pac contains one
less ring set than conventional packing. It is speculated that this "missing seal" can cause
increases in rod emissions while the compressor is in operating mode. However, industry
experience suggests that the Static-Pac should not affect normal sealing during compressor
operation. The Center was unable to locate reliable data to verily this claim. Therefore, the
verification test approach, described in Section 2.2, assesses the effect (if any) of the Static-Pac
on normal sealing performance during compressor operation. This was accomplished by fitting
one rod on a test engine with a Static-Pac and the second rod with new conventional packing. A
second engine was fitted in the same manner to provide duplicate measurements.
Figure 1-3. Static-Pac Actuation and Deactuation Process
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GAS INLET
STATIC-PAC
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PACKING CASE I
SEAL f$ ACTUATED ONLY WHEN ROD IS AT REST
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WHEN ACTIVATED, SEAL CONTACTS ROD.
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"Static-Pac" is a registered trademark of C. Lee Cook
covered by Patent No. 4469017.
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1.3
VERIFICATION GOALS
Compressor shutdown and standby procedures vary from station to station. Some operators
depressurize and blow down all pressure from a compressor before placing the unit into standby
mode. Others depressurize the compressor to a lower but elevated pressure, while still others
maintain full pressure during standby. Adding the Static-Pac to a compressor may result in
varying levels of net gas savings and emission reductions depending on the shutdown procedure
used.
The evaluation of the Static-Pac focused on two shutdown procedures that represent the most
common approaches to compressor shutdown: remain pressurized during idle; and depressurized
(blowdown) before idle. These shutdown modes are discussed in Section 2.1. The Phase I and II
verification goals and parameters associated with these two compressor shutdown scenarios are
outlined below.
Phase I Evaluation:
Verify gas savings
Verify installation and shakedown requirements
Verify capital and installation costs
Phase II Evaluation:
Verify annual gas savings
Verify annual methane emission reduction
Calculate and document Static-Pac payback period
Phase I goals were achieved through observation, collection and analyses of direct gas
measurements, and the use of site logs and vendor supplied cost and operational data. The
evaluation was completed after about a 3-week period of measurements. Gas savings were based
on two sets of manual emission measurements. The number and duration of shutdowns were
determined from site records provided by ANR Pipeline Company for the testing period.
Measured emission rates, site operational data, estimated gas savings, and installation
requirements were documented and verified in the Phase I report.
The primary goal of the Phase II evaluation was to determine the Static-Pac payback period. As a
practical matter, the Center could not conduct testing for the number of years that would be
required to determine payback from direct measurements. Thus, the Phase II goals were
accomplished through a combination of the measurements conducted during the Phase I test
period and 3 additional months of Phase II measurements.
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2.0 TECHNICAL BACKGROUND AND VERIFICATION APPROACH
2.1 METHANE EMISSIONS FROM NATURAL GAS COMPRESSORS
Fugitive natural gas emissions from compressor stations account for a significant loss in revenue
and natural resources. These emissions also contribute to the release of methane, a potent
greenhouse gas, into the atmosphere. Prior EPA and Gas Research Institute studies estimated that
reciprocating compressors emitted approximately 21 percent of the total gas emissions (314 x 109
ft3) from the natural gas industry in 1992 (Harrison et al., 1996).
Methane emissions from compressors are liberated from a variety of different sources. These
sources include leaks from the rod packing, unit valves, blowdown valve, pressure relief valve,
and miscellaneous valves, fittings, and other devices. Emissions are also significant from blow-
down operations that occur prior to placing a compressor into standby mode or taking it off-line.
Fugitive natural gas emissions associated with compressor rod packing occur from operating
compressors, but emissions also occur when some compressors are placed into a standby or idle
mode while remaining pressurized.
According to an ongoing, multiyear fugitive emissions study conducted by the Pipeline Research
Committee (PRC), very little difference was observed between compressor rod packing emissions
during normal operations and during pressurized standby or idle mode operations. The overall
average leak rate was approximately 1.86 cfm per rod (GRI 1997). This emission rate is higher
than the 0.86 cfm per rod reported previously in an EPA/GRI study (Hummel et al., 1996). The
PRC results are based on data collected from nine compressor stations, containing 56
reciprocating compressors and readings taken at 365 individual rod packing, compared to 135
measurements at six compressor stations in the EPA/GRI study. Nevertheless, both data sets are
very useful in quantifying average rod emission rates throughout the natural gas industry.
Fugitive emissions from standby or idle mode compressors are affected by the compressor
shutdown mode. This varies from station to station and, in general, the following procedures are
used:
• Maintain full operating pressure when idle (either with or without the unit
isolation valves open),
• Depressurize and blow down all pressure when idle (except a small residual
pressure to prevent air in-leakage) and vent the gas, either partially or
completely, to the atmosphere,
• Depressurize to a lower pressure, venting the gas either to the atmosphere or
to the station fuel system, or
• A combination of these procedures.
Based on the EPA/GRI study, the first two operating procedures represent the most common
approaches to compressor shutdown (Harrison et al., 1996). The study estimated that about 57
percent of idle transmission compressors are maintained at operating pressures and 38 percent are
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blown down to the atmosphere. A smaller percentage (less than 5 percent) are blown down to a
lower pressure, in some cases venting to the station's fuel system.
2.2 DESCRIPTION OF THE TEST SITE AND STATIC-PAC INSTALLATION
Reciprocating compressors are the type most commonly used within the gas industry, and are a
primary source of compressor-related emissions. Thus, the Static-Pac verification was conducted
at a transmission station that uses reciprocating compressors. ANR Pipeline Company expressed
interest in hosting the verification, and assisted the Center in identifying an appropriate
compressor station within their pipeline system. ANR reviewed its operations and identified
facilities where: the Static-Pac was not currently used; at least one compressor operates in a
shutdown mode several times a year; and site operators could cooperate in support of the short-
and long-term evaluations.
The natural gas transmission station selected to host the Static-Pac verification operates six
Cooper-Bessemer engines (8-cylinder, 2000 hp), each equipped with two reciprocating
compressors operating in series (4,275 in.3 displacement, 4-inch diameter rods). The low-speed
engines at the site are typical of many used in the industry, but may not be typical of newer, high-
speed engines in use. The rods and packing cases have the same basic design and function as
most reciprocating compressors currently used and planned for use in the future in the
transmission sector. The rod packing is essentially a dry seal system, using only a few ounces of
lubricant per day. Wet seals, which use high-pressure oil to form a barrier against escaping gas,
have traditionally been employed. According to the Natural Gas STAR partners, dry seal systems
have recently come into favor because of lower power requirements, improved compressor and
pipeline operating efficiency and performance, enhanced compressor reliability, and reduced
maintenance. The STAR industry partners report that about 50 percent of new seal replacements
consist of dry seal systems.
Two engines, designated as Engines 801 and 802, were selected to verify the performance of the
Static-Pac system. These two engines are the same age and have similar operating hours. Actual
operating hours on each engine are logged continuously. Each engine contains two compressor
rods, and nine cups are contained in each packing case. All rods are made of chrome-plated steel.
The Static-Pac was installed on one compressor rod on each of the two engines and included a
new packing case and seals. This rod is referred to as the Test Rod. The packing material on the
second rod on each engine was replaced with new packing at the same time the Static-Pac was
installed. The second rod used conventional packing and served as a Control Rod against which
Static-Pac performance could be compared. The conventional packing normally used at the site
is manufactured by C. Lee Cook. The comparisons were conducted both for idle periods and
while the engine was running to determine if the elimination of one of the seals in the Static-Pac
design affects normal sealing performance during compressor operation.
2.3 VERIFICATION APPROACH
According to C. Lee Cook, the Static-Pac can provide static sealing during idle periods, provided
the compressor remains pressurized while idle. The gas savings achieved by the rod packing
depend on the emission characteristics of the compressor's packing, both before and after
installation of the Static-Pac. Savings also depend on the shutdown procedures used, and the
number and duration of shutdowns experienced. A station that currently leaves compressors
pressurized during shutdown will achieve net savings from the decrease in rod packing leaks
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during idle periods. Alternatively, a station that currently blows down compressors before
shutdown would change to a pressurized shutdown procedure, and this change in operating
practice would result in both increases and decreases in emissions from various compressor
components. A likely scenario for such a change would be that the station wishes to eliminate
blowdown emissions, and employs a static sealing system at the same time to reduce or eliminate
any additional emission from the newly pressurized, rod packing. In this case, gas savings occur
by eliminating blowdown emissions and unit valve leaks. However, there is a potential for
increases in emissions from components now exposed to high pressure during shutdown,
including the rod packing.
This section presents the approach used to calculated gas savings associated with the Cook Static-
Pac for Engines 801 and 802. Two base-case shutdown/idle modes are assumed. Case 1
represents the original use of a pressurized shutdown (same as Static-Pac requires), and Case 2
represents the original use of compressor depressurization and blowdown. As a result of
changing the packing, and possibly the shutdown/idle mode, a variety of emission changes
occurred in both cases. Each change was quantified during the verification through measurement
of the values listed below:
• Case 1 rod seal savings while idle;
• Case 1 rod seal losses due to emissions increases while running;
• Case 2 rod seal increases while idle;
• Case 2 rod seal losses due to emissions increases while running ~ same as in
Case 1;
• Blowdown volume savings;
• Blowdown valve leak losses;
• Unit valve leak savings; and
• PRV and miscellaneous component losses.
2.3.1 Determining Gas Savings and Payback
For the two most commonly used compressor shutdown scenarios described in Section 2.1, Table
2-1 shows the relationship between compressor shutdown procedures and emissions. Because
use of the Static-Pac system is associated with pressurized compressor standby operation, the
table indicates how compressor emissions may change from the emissions that occurred during
the original standby mode. Using this table as a guide, a verification plan was developed to
characterize all the emissions changes that may occur with the installation of the Static-Pac and
the possible adoption of a different shutdown procedure.
The evaluation of the Static-Pac performance at ANR Pipeline Company focused on the two
shutdown scenarios that collectively represent practices employed by about 95 percent of the
transmission compressors (Shires and Harrison 1996). Case 1 represents compressors that remain
pressurized when idle, and Case 2 represents compressors that completely depressurize and blow
down all gas. The host site was asked to follow these practices during testing, although their
normal practice is to maintain idle pressures of about 120 psig and recover all blowdown gas into
the engine fuel system. The following discussion highlights the verification issues for each case
and outlines measurements and data collection activities implemented in the verification test.
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2.3.1.1
Case 1
The baseline for Case 1 is a compressor that normally maintains full operating pressure during
idle periods. For this case, a change in emissions was anticipated to occur only at the rod packing
due to the static sealing action of the Static-Pac. To quantify this potential change in rod packing
leaks, direct gas emission rate measurements were conducted on the distance piece or doghouse
vent pipes associated with the Control Rods and Test Rods for each of the two engines. Because
the unit pressure is essentially unchanged during both operating and idle periods, all leak rates
from other components (pressure relief valve, blowdown valve, unit valves, and miscellaneous
flanges, valves, and fittings) can be assumed to remain constant after installation of the Static-
Pac. The idle-mode emissions from the two Control Rods are compared to idle-mode emissions
from the two Test Rods. The difference between these two values is determined, and used to
quantify the static sealing abilities of the Static-Pac.
Table 2-1. Common Shutdown Scenarios and Emissions
Matrix of Shutdown Procedure Changes
Shutdown Procedure or
Emission Source
CASE 1
CASE 2
Current shutdown
procedure
Pressurized shutdown with
unit valves open or closed3
Blowdown/100% vent to
atmosphere
New procedure with
Static-Pac
n/cb
Pressurized shutdown
Matrix of Possible Emissions Changes Due to Shutdown Procedure Changes or
Installation of the Static-Pac
Rod seals
Decrease
Little or no increase
Blowdown volume
n/c
Decrease
Unit valve seat (via open
blowdown line)
n/c
Decrease
Blowdown valve
n/c
Increase
Pressure relief valve
n/c
Increase
Misc. valves, fittings,
flanges, stems etc.
n/c
Increase
a Most sites leave the unit valves closed for safety reasons (i.e., sites may not want problems in the shutdown
engine to affect the integrity of the entire station).
b n/c - no change/effectively no change.
For Case 1, the savings consist solely of gas prevented from leaking from the rod packing during
idle periods. This is the difference between the average leak rate without the Static-Pac
(measured for the Control Rods) and the average leak rate with the Static-Pac (measured for the
Test Rods). Average uncontrolled leak rate is defined as the average of all measurements made
on the two Control Rods and average controlled leak rate is the average of all measurements
made on the two Test Rods. Equation 1 states how gas savings will be calculated for each test
engine.
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G1 = [Qu - Qs] * t
(Eqn. 1)
where,
G1 = average gas savings for each engine (Case 1), scf
Qu = average uncontrolled leak rate while idle (Control Rods), scfm
Qs = average controlled leak rate while idle (Test Rods), scfm
t = total shutdown or idle time during verification period, minutes
2.3.1.2 Case 2
The baseline for Case 2 is a compressor that normally blows down from operating pressure to a
minimum pressure during idle periods. At such times the pressure on compressor components is
reduced to near atmospheric. Consequently, leaks from rod packing, pressure relief valves, and
blowdown valves cease to exist. However, leaks from the unit valves, which are closed to isolate
the compressor from the pipeline, are liberated into the atmosphere. This gas leaks past the unit
valves, into the compressor system, and out into the atmosphere via the open blowdown valve.
Figure 2-1 is a simplified diagram of these emission sources. Because emissions associated with
leaking unit valves can be substantial, measurements were made to quantify these emissions after
blowdown was completed. In addition, the compressed gas contained in the compressor and
associated piping is lost during blowdown. These savings were calculated based on known
volumes of compressor components, the measured operating pressure, and the measured gas
composition. All of these emission savings are added together to calculate a total gas savings as a
result of changing from a blowdown practice to remaining pressurized.
2-5
-------
Figure 2-1. Compressor/Engine Configuration and Emissions Sources
Blowdown Valve and Vent
Compressoi
Doghouse
Pressure Relief Valve
and Vent
.Unit Isolation
Valves
Doghouse
Vent
^ Main Station Suction
Line (inlet)
Main Station Discharge
Line (outlet)
In contrast, emissions can increase from several components that are now exposed to high
pressure. This includes increase in leaks from the pressure relief valve, blowdown valve, various
flanges, connectors, and valves, and the rod packing where the Static-Pac is installed. The Static-
Pac serves to reduce the increase in rod packing emissions relative to a conventional packing
when the unit remains pressurized when idle. Ultimately, these leaks decrease the total gas
savings associated with the blowdown practice. To verify the emission contribution of these
sources, gas emission rate measurements were conducted (during pressurized idle-mode) on all
components newly exposed to elevated pressures. Emissions from these devices are subtracted
from the total savings above, to yield the net savings associated with changing the operating
practice and installing a Static-Pac.
For Case 2, gas savings consist of the blowdown volume (times the number of blowdown events)
and the unit valve leak rate (times the duration of idle periods). In addition, there could be gas
leakage from the blowdown valve, pressure relief valves, and miscellaneous components.
Additionally, any gas that escapes past the Static-Pac is lost (i.e., pressurized conditions may
result in packing case leaks which are essentially zero during non-pressurized/blowdown
conditions). For Case 2, the gas savings for each idle period were calculated as follows.
G2 = BDV + Quv * t - [Qprv + Qbdv + Qmisc + Qs] * t (Eqn. 2)
where,
2-6
-------
G2 = gas savings for each engine (Case 2), scf
BDV = blowdown volume times the number of blowdowns during the verification
period, scf
Quv = unit valve leak rate, scfm
t = idle time over the verification period, minutes
Qprv = pressure relief valve leak rate, scfm
Qbdv = blowdown valve leak rate, scfm
Qmisc = aggregate leak rate for miscellaneous components, scfm
Qs = rod leak rate with Static-Pac, scfm
2.3.1.3 Impact on Normal Running Emissions
With the Static-Pac system, the packing case is modified, resulting in one less set of rings than
conventional packing cases. With this change, there is a potential to alter the emission sealing
performance of the overall packing system (i.e., cause an increase or decrease in packing
emissions compared to the standard packing). To address this, measurements were conducted on
the Test and Control Rods during normal operations and the emission rates were then compared.
It is assumed that, after installation of the Static-Pac, the unit valve position (i.e., closed or open)
would remain the same as before the Static-Pac was installed.
If the Static-Pac caused any increase in emissions during normal compressor operation, these
emissions were subtracted from the gas savings. The following equation states how the total gas
savings were calculated for each case. The total gas savings, G1T and G2T, for Case 1 and Case
2, respectively, are given in Equations 3 and 4.
G1t — G1 - Vm (Eqn. 3)
Where, Vm is any increase in operating emissions that occurred over the test period due to the
Static-Pac. Vm is the difference in operating emissions (i.e., emissions during non-idle periods)
between the Test and Control Rods, times the number of minutes the compressor operated during
the verification period.
G2j = G2 - Vm (Eqn. 4)
2.3.1.4 Annual Gas Savings and Payback Period
Annual Gas Savings
Case 1 and Case 2 gas savings rates for the verification period are computed using Equations 1
and 2. Since the test did not span an entire year, it was necessary to project gas savings over this
longer period. During the development of the Test Plan, it was expected that compressor rod
emission rates would increase over time due to wear on the packing. To account for this, the
initial testing strategy proposed extrapolating the measured data to project increasing leak rate
trends over time. The projected annual gas savings rate was to be projected as a likely case and a
conservative case. The likely case would extrapolate future increases in leak rates based on
2-7
-------
increases observed during the test period. The conservative case assumes that the gas savings rate
will not follow an increasing trend, but will be the same as the rate measured at the conclusion of
the test.
As discussed in Section 3.4.2, the measurements data collected during the test did not reveal
increasing trends in rod leak rates over time. As a result, the initially planned extrapolation
routine for the likely case could not be executed, and the conservative approach was followed.
The annual gas savings rate was determined as the average gas savings rate (Control Rod minus
Test Rod) measured during the testing period (July 14, 1999, to January 26, 2000). This average
savings rate was multiplied by the average annual engine idle time as reported by ANR. The
monetary value associated with the use of the Static-Pac for Case 1 was calculated by multiplying
this average saving by an assigned value of $2 per 1,000 ft3 of gas saved.
Annual Methane Emission Reductions
The calculated annual gas savings were also used to determine annual methane emission
reductions. This was accomplished by multiplying the natural gas savings (discussed above) with
the average methane content of the natural gas at the site. The methane content data were
obtained from gas sampling analyses routinely collected by ANR.
Static-Pac Payback Period
The Center's Stakeholder group has identified payback as an indicator of economic performance
for technologies verified under the ETV program. Under the payback method of analysis,
purchases with shorter payback periods are ranked higher than those with longer paybacks. The
theory is that devices with shorter paybacks are more liquid, and thus less risky (i.e., they allow
initial investment to be recouped sooner such that the money can be reinvested elsewhere).
Projects with longer payback periods can bring uncertainty in economics over time due to
potential changes in market conditions, interest rates, or the economy. Generally, a payback
period of less than 3 years is considered favorable by the gas industry stakeholders, and the
chances of its implementation are high. If the payback is less than 5 years, the technology is
likely to receive some consideration.
Payback is the expected length of time required for the future cash inflows from a capital
investment to fully repay the original capital cost. Future incomes and expenses are discounted to
the beginning of the analytical period, using an interest rate that represents the minimum
acceptable rate of return for the industry. The stakeholders have identified this rate of return to be
10 percent. Payback is calculated using Equation 5 as follows:
(1) Estimating the costs (capital investment in the beginning year; operations,
maintenance, overhead, etc. in all later years) and benefits (cost savings, revenues
earned, etc.) for each year of the device's useful life.
(2) Discounting each year's net value (benefits minus costs) to the beginning year
using an appropriate discount rate and formula.
(3) Sequentially adding each year's discounted value of its cash flows to the beginning
year value until the discounted net present value of the device is no longer
negative.
(4) Identifying the year that causes the aggregated net present value in (3) to be zero or
greater as the payback period.
2-8
-------
Appendix A displays the payback calculation in tabular form. Payback is one of many ways of
examining the economic viability of a technology, including internal rate of return and net present
value over the life of the device. Unlike the latter two methods, payback has several drawbacks.
First, it ignores any additional costs that may be incurred after the payback period, so a
technology that has a shorter useful life may be favored over a technology that lasts longer but
has a longer payback period. Payback also ignores additional benefits that may occur after the
payback period.
..m, „ . , Gas Savings in Year t _
NPV = Capital Cost - ^^ 6 (Eqn. 5)
Payback Period (yrs) = first year when PV >0
Where :
NPV = net present value
t = year
r = discount rate of return, 10%
2.3.2 Emission Measurements and Calculations
The following discussion provides an overview of the measurements made, instruments used,
field procedures followed, and key calculations made in the Phase I and II tests. For more detail
on these topics, the reader should consult the Test Plan titled Testing and Quality Assurance Plan
for the C. Lee Cook Division, Dover Corporation Static-PacIM System (July 1999). It can be
downloaded from the Center's web site at www sri-rtp.com.
To characterize the running emissions and Case 1/Case 2 idle emissions, manual emission
measurements were collected on the following sources: doghouse vent, unit valve seat (via the
open blowdown line), pressure relief valve vent, blowdown valve vent, and miscellaneous
components (e.g., fittings, connections, valve stems). The measurements made and operating
conditions under which testing was performed are listed below. One full day was needed to
conduct this suite of measurements on both engines.
• With both units shut down and pressurized: natural gas leak rates for the
pressure relief valve, blowdown valve, miscellaneous components, and rod
packing vents (test rod and control rod)
• With both units blown down: natural gas leak rates for the unit valve and unit
valve stem
• With both units running: natural gas leak rates for the rod packing vents (Test
Rod and Control Rod)
Measured natural gas leak rates were converted to methane leak rates using natural gas
compositional measurements provided by ANR Pipeline (about 97 percent methane). The
2-9
-------
measurements are conducted using a gas chromatograph located along the pipeline at 4-hour
intervals.
The station agreed to a limited number of unscheduled shutdowns for the purpose of conducting
the measurements described above. Results from these tests were used to characterize emission
rates at the time of testing, and to characterize emissions differences between Cases 1 and 2,
above. Net gas savings were calculated based on the number and duration of idle periods
encountered at the site for the test period.
2.3.2.1 Rod Leak Rate Measurements
Emissions from the packing case vent and leaking rod seals are both vented into the distance
piece or doghouse described in Section 1.2. Both emission sources vent gas that has escaped the
sealing action of the packing, and are included together when measuring emissions. After
emissions are discharged into the doghouse, they are vented to the atmosphere through the
doghouse vent. Soap screening all doghouse seals and connections, and monitoring the long-term
compositional trends of the gas exiting the doghouse, was done to ensure that no other gas was
entering the doghouse during the testing. The doghouse vent and oil drain are the only paths by
which emissions escape into the atmosphere and for the test, the doghouse oil drain was sealed
using ball valves. This forced all emissions to exit through the doghouse vent.
To measure these emissions, a Flow Tube was used to measure vent gas velocity, and a
hydrocarbon analyzer was used to measure vent gas total hydrocarbon (THC) concentration
before flow measurement started. In the original Test Plan, sensitive, low-pressure-drop
continuous flow meters were planned for use, but after their installation, it was determined that
the pressure in the doghouse vents was so low that reliable flow detection could not be
established. With this discovery, the decision was made to proceed with manual testing, and to
use sensitive manual methods to conduct the measurements.
The Flow Tube consists of a sensitive 1-inch vane anemometer mounted on the inside walls of a
polyvinyl chloride (PVC) tube that measures 30 inches in length and 1 inch in diameter. During
the Phase I testing, it was determined that idle emissions with the Static-Pac engaged were
sometimes below the level of detection of the vane anemometer (which is approximately 0.12
scfm natural gas). Therefore, the vane anemometer in the Flow Tube was replaced with a thermal
anemometer for Phase II testing and used in cases where emissions were below the detectable
level of the vane anemometer. The thermal anemometer is an intrinsically safe device capable of
detecting low level flow rates (detection limit of approximately 0.01 scfm). Table 2-2 provides
the ranges of the two types of anemometers used for the testing.
Table 2-2. Anemometer Range of Detection in Flow Tube
Type of
Anemometer
Lower Detection Limit
Upper
Range3
fpm
scfmb
fpm
scfmb
Vane
60
0.12
6800
20
Thermal
25
0.01
NA
NA
a The thermal anemometer was only used at or near its lower detection limit.
b The scfm values are for methane and represent the average flow rates determined through laboratory calibrations
using methane (99.9 percent pure).
2-10
-------
Before each manual measurements campaign at the site, the Flow Tube was laboratory-calibrated
using a NIST-traceable Laminar Flow Element and a wide range of simulated gas flow rates (99
percent methane, 0.3 to 4 scfm for the vane anemometer and 0.02 to 1 scfm for the thermal
anemometer). These calibrations were used to generate calibration curves that spanned the range
of flow rates anticipated for the site. These curves were used to select a gas flow rate based on
the indicated velocity from the flow tube. An example calibration chart is shown in Figure 2-2
for a flow tube equipped with the vane anemometer.
Serial No: 40-90-09690 (12/10/99)
1.80
1.60
y = 0.003x-0.0055
R2 = 0.9986
1.40
1.20
E
4—
o
«. 1.00
|
il 0.80
to
ns
O
0.60
0.40
0.20
0.00 *
0
100
200
300
400
500
600
Gas Velocity (fpm)
X 12/10 run 1
Linear (12/10 run 1)
For each doghouse vent, one testing event consisted of a minimum of 10 separate gas velocity
readings measured with the Flow Tube. These readings were made after the doghouse emissions
were observed to stabilize (15 to 20 minutes after the vents were opened). In most cases, the 10
readings showed stable emissions. Each reading represents a 16-second average value and, after
completion, all values were averaged to yield an overall average total gas flow rate in feet per
minute. Using this value, a natural gas flow rate was selected from the flow tube calibration
curve.
With the thermal anemometer inserted in the Flow Tube, the device had a Lower Detectable
Limit (LDL) of 0.010 scfm (i.e., flow rates below this value cannot be reliably detected with the
instrument). When gas flows lower than the LDL were encountered, a gas flow rate equal to half
the LDL (0.005 scfm) was assigned.
It should be noted that, after opening the doghouse vent for measurement, air typically enters and
mixes with the natural gas leaking from the rod packing. Just before taking velocity readings, the
hydrocarbon concentration in the doghouse vent was measured using a portable hydrocarbon
2-11
-------
analyzer. The analyzer used was a Bascom-Turner CGI-201, with a 4-100 percent total
hydrocarbon range, and an accuracy of 2 percent of the measured concentration. The CGI-201
measures all primary hydrocarbon compounds found in natural gas including methane, ethane,
propane, and butane (over 90 percent is methane).
Given sufficient time, the rod leaks would completely purge all air from the doghouse, allowing
direct measurement of pure natural gas with the Flow Tube. As a practical matter, this could not
be done routinely. Based on the Center's experience with characterizing doghouse vent
emissions at several compressor facilities, it is believed that the rod packing leak and vent is the
driving force which results in gas escaping through the vents (i.e., only one outlet stream is
present for the gas to escape and no other gas can enter the doghouse). As such, it is assumed that
the flow rate measured during testing is representative of the flow rate of pure natural gas leaking
from the packing. This assumption was verified by monitoring composition on two vents over
time (about 1 hour), and verifying that the composition eventually reached 92 to 94 percent THC.
2.3.2.2 Component Leak Rate Measurements
Manual measurements were made for the pressure relief valve, unit valve, blowdown valve, and
miscellaneous components on each engine. The Center was unable to obtain a license to use the
GRI Hi-Flow device as described in the Test Plan. Consequently, the Flow Tube, proven to be
reliable on other similar measurements conducted by the Center, including the Phase I test, was
used for the Phase II testing.
The pressure relief valve vents through a 6-inch diameter standpipe extending to the roof of the
compressor building. Access to the roof was limited, and posed a hazard to the testing personnel.
Thus, a hydrocarbon analyzer was first used to determine if leaks were present and if detected, the
Flow Tube was to be used to quantify the gas flow rates. With the exception of making a direct
connection to the 6-inch standpipe outlet, the sampling and calibration procedures described in
the previous section apply to this emission source as well.
For the unit valves, flow measurements were conducted at an existing port, located immediately
downstream of the unit valves in the suction line of each compressor. During compressor
shutdown, any leaks from the seats of the unit valves will exit through this opened port. The leak
rate for the unit valves was the highest flow measured at the host site. The leak rate was
measured using the same Flow Tube applied to the rod packing vents. The anemometer mounted
within the tube has the capacity to measure the high flows that occurred (e.g., a maximum of
6,800 fpm or about 20 cfm of natural gas could be measured). A different calibration chart with a
greater range was used to determine emission rates at the higher flows encountered with unit
valves leaks (Section 4 has additional information on calibration).
During the Phase I testing, the leak rate for the blowdown valve was measured at the flange
located at the exit of the valve. To make this measurement, it was necessary to unbolt the flange,
then separate the two sides by about 1 inch and then insert a disk. A sensitive low-flow-rate
rotameter (Dwyer VB Series, 0 to 1000 mL/min with a published accuracy and precision of +3
percent) was used to measure flows. No leaks were detected from either unit during Phase I.
Because this measurement required significant host facility labor and leak rates were consistently
found to be negligible, the measurements were not repeated during Phase II. It is assumed that
the blowdown valves were not leaking.
2-12
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The miscellaneous components at the test site consist of pressure and temperature metering taps,
fittings that connect the taps to data transmitters, and valves used to recover gas for the fuel
recovery system. The host station normally vents to a specially designed gas recovery system
during shutdown, but performed a blowdown procedure for this verification, allowing an
assessment of the Case 1 and Case 2 shutdown scenarios described above. Significant leaks were
not expected at these locations; however, all components were soap screened and any leaks
identified were to be quantified using the EPA protocol tent/bag method.
2.3.2.3 Natural Gas Composition Measurements
On-site natural gas compositional analysis is performed by ANR personnel. The site operators
use a gas chromatograph (Daniel Model #2251) to determine the concentration of methane,
hydrocarbons, and inert gas species present in the pipeline gas. The gas chromatograph is
capable of measuring 0 to 100 percent methane, with an instrument accuracy and precision of
+0.02 percent of full range. The instrument is calibrated each month using 97.0 percent certified
methane gas.
The Center obtained copies of the fuel gas analyses results and their calibration records that
corresponded to the Phase II measurements. An average methane concentration was calculated
for those days when sampling was conducted.
2.3.2.4 Blowdown Volume Determination
The blowdown volume represents gas contained in the test compressor, engine, auxiliary piping,
and all components located downstream of the unit valves. Based on records obtained from ANR,
the total volume present in this equipment is 176 ft3. ANR engineers determined that at 600 psig
blowdown pressure, 9,200 scf of natural gas occupies this volume (corrected for the methane
compressibility factor). Because it is not feasible or safe to directly measure blowdown volume,
9,200 scf was used to represent the total gas released into the atmosphere each time the test
compressor is depressurized from 600 to 0 psig.
2.3.3 Engine Operational Data
The number and duration of shutdown/idle periods must be specified to calculate the gas savings
that occurred during the test period, and to estimate total idle hours anticipated at the site during a
single year. Site records, provided by ANR pipeline from January 1999 through March 2000,
were used to determine the number and duration of shutdowns for the test period and throughout
a typical year. The ANR records identify daily compressor operating hours and the total hours
the compressor was available (i.e., scheduled shutdown for maintenance is not included in the
available hour values). Subtraction of the total available hours from the total operating hours
yields the number of hours each unit was in standby or idle mode operations. Because the
number and duration of shutdowns were manipulated by the Center to ensure collection of the
necessary measurements, those shutdowns that occurred at the Center's request were subtracted.
The number of blowdowns was determined by accounting for each occurrence of an idle period.
It should be noted that this is an estimated value because the test site does not normally blow-
down, but rather maintains a minimum pressure of 120 psig on the compressors during idle
periods. The number of blowdown occurrences assigned for the Case 2 evaluation was
determined based on the average number of engine shutdown occurrences for the two engines
during the verification period.
2-13
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3.0 RESULTS
The verification testing was conducted during five separate visits to the station beginning on July
15, 1999, and ending on January 26, 2000. Results of all of the tests conducted during both
Phases of the verification are presented in this section and include:
Section 3.1 - Rod Packing Emissions
Section 3.2 - Other Emission Sources
Section 3.3 - Net Gas Savings
Section 3.4 - Annual Gas Savings
Section 3.5 - Payback Period
Each of the results sections presents the results of the verification and the performance of the
Static-Pac as measured on the test engines. As the results will show, the uncontrolled rod leak
rates on the test engines were much lower than the industry averages reported in past GRI studies
(Section 2.1). Moreover, the test engines were equipped with only two compressors while the
GRI study found the industry average to be 3.3 rods per engine (GRI 1997). The overall gas
leaking from the two test engines was unusually low. To provide a representative assessment of
Static-Pac performance, Sections 3.4 and 3.5 also include projected annual gas savings and
payback for industry average rod leak rates using the GRI data.
Variability in these measurements was determined using a student t distribution test based on a
confidence coefficient of 95 percent and the variability is reported with each of the average
measurement results reported. Section 4.0 discusses Data Quality and will show that the
variability was primarily a result of process variability (and not instrument or procedure related).
3.1 ROD PACKING EMISSIONS
3.1.1 Emissions During Idle/Shutdown
Table 3-1 presents the measured rod packing leak rates for Engines 801 and 802 during
pressurized idle states. The table includes all data collected during Phase I and three more field
campaigns conducted during the Phase II testing. Each campaign consisted of approximately 3
days of testing each. These data span a time range of just over 6 months and include the period
from when the packing was first installed to about 4,000 hours of wear. Measurements were
generally started 20 minutes after shutdown occurred, and required about 30 minutes to complete.
Thus, the values reported below are representative of average emissions that occurred within
about 45 minutes of compressor shutdown (unless the engine had been shut down overnight).
For all of the Phase II tests, the thermal anemometer was used in the Flow Tube to detect
emissions from the Test Rod with the Static-Pac engaged. Idle emissions from the Control Rods
were detectable with the vane anemometer. For all but one of the Test Rod measurements, the
anemometer detected flows of 0.028 scfm or less.
3-1
-------
Table 3-1. Rod Seal Leak Rate
(Units Idle and Pressurized)
Date
Approx. Run Time
on New Seals (hrs)
Control Rod / Test
Rod
Engine Idle,
Pressurized @ -600 psi
Difference
Between
Control
Road and
Test Rod,"
scfm
natural gas
Natural
Gas
Emissions
Reduction
(%)
Control Rod With
Conventional
Packing, scfm
natural gas
Test Rod With
Static-Pac,
scfm natural gas
ENGINE 801
7/15/99
17/1340
0.920
0.020
0.900
97.8
7/16/99
37/ 1365
0.720
0.020
0.700
97.2
8/4/99
520/ 1850
0.020b
0.010b'd
na
na
8/5/99
540 / 1870
0.020b
0.010M
na
na
8/6/99
563 / 1893
0.500
0.010d
0.490
98.0
9/21/99
1206 / 1536
0.527
0.022
0.505
95.8
9/21/99
1209 / 1539
0.634
0.024
0.610
96.2
9/22/99
1230 / 1560
0.507
0.024
0.483
95.3
12/7/99
2502 / 3833
0.581
0.023
0.558
96.0
12/7/99
2505 / 3836
0.544
0.023
0.521
95.8
12/8/99
2512 /3842
0.036b
0.024b
na
na
12/9/99
2526 / 3856
0.226
0.022
0.204
90.3
12/9/99
2528 / 3858
0.021b
0.021b
na
na
1/26/00
3186 /4516
0.686
0.021
0.665
96.9
1/26/00
3187 /4517
0.740
0.019
0.721
97.4
1/26/00
3189 /4519
0.755
0.018
0.737
97.6
1/27/00
3191 / 4521
0.592
0.020
0.572
96.6
801 Average
0.610
0.020
0.590
96.2
801 Standard Deviation
0.170
0.004
0.170
2.0
801 Confidence Coefficient1
0.101
0.002
0.101
ENGINE 802
7/16/99
19/19
0.790
0.020
0.770
97.5
8/4/99
509 / 509
0.020b
0.020b
na
na
8/5/99
533 / 533
1.130
0.010d
1.120
99.1
8/6/99
559 / 559
0.400
0.010d
0.390
97.5
9/22/99
1527 / 1527
0.318
0.025
0.293
92.1
9/22/99
1529 / 1529
0.365
0.016
0.349
95.6
9/23/99
1537 / 1537
0.497
0.027
0.470
94.6
9/23/99
1539 / 1539
0.535
0.023
0.512
95.7
12/7/99
2885 / 2885
0.287
0.030
0.257
89.5
12/8/99
2900 / 2900
0.431
0.005d
0.426
98.8
12/8/99
2903 / 2903
0.490
0.011
0.479
97.8
1/25/00
3597 / 3597
0.349
0.014
0.335
96.0
1/25/00
3599 / 3599
0.369
0.028
0.341
92.4
1/25/00
3602 / 3602
0.373
0.010
0.363
97.3
1/26/00
3605 / 3605
0.288
0.019
0.269
93.4
1/26/00
3607 / 3607
0.301
0.017
0.284
94.4
1/26/00
3609 / 3609
0.316
0.013
0.303
95.9
802 Average
0.452
0.017
0.435
95.5
802 Standard Deviation
0.220
0.008
0.220
2.6
802 Confidence Coefficient1
0.118
0.004
0.119
(continued)
3-2
-------
Table 3-1. Rod Seal Leak Rate (continued)
(Units Idle and Pressurized)
Date
Approx. Run Time
on New Seals (hrs)
Control Rod / Test
Rod
Engine Idle,
Pressurized @ -600 psi
Difference
Between
Control
Road and
Test Rod,"
scfm
natural gas
Natural
Gas
Emissions
Reduction
(%)
Control Rod With
Conventional
Packing, scfm
natural gas
Test Rod With
Static-Pac,
scfm natural gas
Overall Average
0.523
0.019
0.504
95.8
Overall Standard Deviation
0.210
0.006
0.210
2.4
Overall Confidence
Coefficient1
0.080
0.002
0.080
a Difference = (Control Rod Leak Rate - Test Rod Leak Rate).
b Anomalous measurements were not used to calculate averages.
c Student t distribution statistical analyses were used. Results are reported at 95% confidence level.
d Represents Non-detectable values. For these samples, a Lower Detectable Limit of 0.010 scfm for the vane
anemometer and 0.005 for the thermal anemometer was assigned.
Four of the tests conducted on Engine 801 and one on 802 were invalidated because the emission
rates measured on the control rods were extremely low compared to the overall data set and were
considered atypical for these compressors. These tests were not used in calculating the overall
average emissions, emission differences, and percent emission reductions reported in Table 3-1.
The average leak rate for the conventional rod packing was determined to be 0.61 scfm for
Engine 801 and 0.45 for Engine 802. The Static-Pac equipped test rod reduced these leaks to
0.02 scfm for both engines. Variability in the measurements data was determined using a student
t distribution test based on a confidence coefficient of 95 percent. All data, with the exception of
percent emission reductions, were found to be normally distributed. The average emission
reduction with the Static-Pac on Engine 801 and 802 was 0.590 +/- 0.083 scfm and 0.44 +/- 0.10
scfm, respectively. This equates to an overall emission reduction efficiency of 96 percent for
both engines.
As discussed in Section 2, the Center was unable to conduct continuous monitoring for Control
and Test rods as originally planned due to low leak rates encountered at the test site. In lieu of
continuous measurements, the number of manual measurements conducted by the Center was
increased to achieve a larger data set. Figure 3-1 illustrates the percent reduction in leak rates
achieved through use of the Static-Pac. The figure illustrates that leak reductions due the Static-
Pac are relatively consistent for both engines, and its performance and leak rate variability over
time are adequately captured by the manually measured data. The figure illustrates that, over a
series of 13 to 16 different measurement samples (sampling over a 6 month period), a wide range
of Control Rod leak rates were encountered (0.23 to 1.13 scfm natural gas). At each one of these
leak rates, the Static-Pac reduced a minimum of 90 percent of the rod packing leak rates. It is
believed that further sampling would not alter these conclusions.
3-3
-------
Figure 3-1. Static-Pac Performance Over Time
1.200
100
1.000
¦•70
g 0.800
0.400
-30
0.200
oortd rod (801)
"10
0.000
1 2 3 4 5 6 7 8 9 10 11 12 13
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
IVfeasueret Series
As described in Section 2.3.1, the approach for determining emission reductions was to compare
the average Control Rod emissions to the average Test Rod emissions with the Static-Pac
engaged. During all of the tests, the Static-Pac was manually disengaged allowing the
comparison of emissions in both the engaged and disengaged position. However, since the
Static-Pac requires the removal of the last set of rings from the packing case, the disengaged
emissions may not be fully representative of conventional packing emissions. The data collected
with the Static-Pac disengaged are not presented in this report for simplicity, but analysis of the
data resulted in an average emissions reduction of 96 percent, the same that was measured using
the Control Rod data.
3.1.2 Emissions During Compressor Operation
Tables 3-2a and 3-2b present the measured packing vent leak rates for Engines 801 and 802
during compressor operation. These data were collected to evaluate if removal of the last set of
rings (to accommodate the Static-Pac) had an effect on emissions during operation. As before,
these data were collected during five trips to the facility and span the range of time of just over 6
months and up to about 4000 hours of wear on the packing.
3-4
-------
For Engine 801, the Static-Pac equipped packing had leak rates while running that averaged 1.31
scfm of natural gas lower than the conventional packing. Conversely, on Engine 802, the Static-
Pac equipped packing had running leak rates that were about 0.23 scfm of natural gas higher than
the conventional packing. Figure 3-2 plots the running leak rates for both engines. The running
leak rates on the 801 control rod are much higher than those observed during Phase I indicating
that the standard packing is starting to leak more during engine operation, while the leak rate with
the Static-Pac equipped rod remained relatively stable. This trend is not present for Engine 802.
Here, both rods are following the same general trend in emission rates over time.
Clearly, removal of the last set of rings would not cause emissions to be lower as indicated on
Engine 801. This suggests that variation in emissions, caused by inherent differences between
compressors such as rod alignment and the condition or effectiveness of primary seals, is more
important than the missing seal associated with the Static-Pac. Some increase in emissions was
measured on Engine 802, although the increase was slight. When the variability of these
measurements is taken into account, the increase in emissions is within the range of measurement
error. The Center therefore concluded that there is not strong evidence suggesting that removal of
the last set of rings causes a significant increase in emissions and for this reason, a running
emissions increase of 0 was used to calculate Case 1 gas savings.
Figure 3-2. Operating Emissions
Control Rod
Sampling Dates
3-5
-------
Table 3-2a. Rod Packing Leak Rates
Engine 801 - Operating
Date
Approx. Run
Time on New
Seals, hrs
Control Rod /
Test Rod
Engine Running @ ~700 psi
Difference Between
Control Rod and
Test Rod,3
scfm natural gas
Control Rod With
Conventional Packing,
scfm natural gas
Test Rod With Static-Pac,
scfm natural gas
ENGINE 801
7/15/99
17/1340
0.87
0.43
0.44
7/16/99
37/ 1365
0.71
0.38
0.33
8/4/99
520 / 1850
0.48
0.01
0.47
8/5/99
540 / 1870
0.42
0.01
0.41
8/6/99
563 / 1893
0.49
0.01
0.48
9/14/99
1038 /2368
1.30
0.05
1.25
9/14/99
1040 / 2370
1.54
0.05
1.49
9/14/99
1042 / 2372
1.55
0.05
1.50
9/14/99
1044 / 2374
1.59
0.05
1.55
9/21/99
1206 / 1536
1.08
0.06
1.02
9/22/99
1230 / 1560
2.35
0.06
2.29
9/22/99
1232 / 1562
1.70
0.06
1.64
9/23/99
1254 / 2584
1.21
0.06
1.15
9/23/99
1256 / 2586
1.30
0.07
1.23
12/7/99
2502 / 3833
1.52
0.26
1.26
12/8/99
2510 /3840
1.60
0.33
1.27
12/8/99
2512 /3842
1.70
0.24
1.46
12/8/99
2514 /3844
1.89
0.18
1.71
1/25/00
3163 /4493
2.07
0.30
1.77
1/25/00
3166 /4496
2.22
0.28
1.94
1/25/00
3168 /4498
2.31
0.29
2.02
1/26/00
3186 /4516
1.57
0.26
1.31
1/27/00
3191 / 4521
2.28
0.20
2.08
801 Average
1.47
0.16
1.31
801 Standard Deviation
0.59
0.13
0.57
801 Confidence
Coefficient"
+0.26
+0.06
+0.25
a Difference = (Control Rod Leak Rate - Test Rod Leak Rate), positive values indicate gas savings are achieved.
b Student t distribution statistical analyses were used. Results are reported at 95% confidence level.
3-6
-------
Table 3-2b. Rod Packing Leak Rates
Engine 802 - Operating
Date
Approx. Run
Time on New
Seals, hrs
Control Rod /
Test Rod
Engine Running @ ~700 psi
Difference Between
Control Rod and
Test Rod,3
scfm natural gas
Control Rod With
Conventional Packing,
scfm natural gas
Test Rod With Static-Pac,
scfm natural gas
7/15/99
l/lb
1.67
2.35
-0.68
7/16/99
19/19
0.92
1.06
-0.14
8/4/99
509 / 509
0.06
0.70
-0.64
8/5/99
533 / 533
0.76
1.35
-0.59
8/6/99
559 / 559
0.47
0.68
-0.21
9/14/99
1348 / 1348
0.05
0.48
-0.42
9/14/99
1350 / 1350
0.04
0.46
-0.41
9/14/99
1352 / 1352
0.04
0.48
-0.43
9/21/99
1517 / 1517
0.36
0.47
-0.11
9/21/99
1519/1519
0.36
0.49
-0.13
9/22/99
1527 / 1527
0.35
0.45
-0.10
12/7/99
2883 / 2883
0.40
0.55
-0.15
12/7/99
2885 / 2885
0.39
0.56
-0.17
12/7/99
2887 / 2887
0.40
0.58
-0.18
12/9/99
2910/2910
0.43
0.52
-0.09
12/9/99
2912/2912
0.40
0.60
-0.20
1/25/00
3597 / 3597
0.35
0.46
-0.11
1/27/00
3609 / 3609
0.43
0.41
0.02
1/27/00
3612 /3612
0.31
0.41
-0.10
802 Average
0.36
0.60
-0.23
802 Standard Deviation
0.23
0.24
0.19
802 Confidence
Coefficient1
+0.11
+0.12
+0.09
Overall Average (801
and 802 Combined)
0.98
0.35
0.63
Overall Standard
Deviation
0.72
0.29
0.89
Overall Confidence
Coefficient1
+0.23
+0.09
+0.28
a Difference = (Control Rod Leak Rate - Test Rod Leak Rate), positive values indicate gas savings are achieved.
b Due to insufficient packing break-in time, this test was not included in the averaging.
c Student t distribution statistical analyses were used. Results are reported at 95% confidence level.
3-7
-------
3.2 OTHER EMISSION SOURCES
3.2.1 Valve Leaks and Slowdown Volume
Measurements were conducted to quantify the leaks associated with the closed and pressurized
blowdown valve, pressure relief valve, and unit valves. Seven measurements were made on the
pressure relief and unit valves on each engine. Three measurements were conducted on each of
the blowdown valves. These measurements represent the natural gas leaking past the valve seats
on each device. Estimates of natural gas venting associated with compressor blowdown
operations are also presented, and are based on ANR-supplied gas pressures and equipment
volumes. The sources addressed in this section are among the most significant fugitive emission
sources associated with compressor operations. Measurements associated with the remaining
minor sources (e.g., valve stems, fittings, and other minor fugitive sources) are addressed in
Section 3.2.2.
The results of these measurements are presented in Table 3-3. There were no detectable leak
rates for both the blowdown valve and the pressure relief valve. Natural gas leak rates for the
unit valves ranged from 1.99 to 6.46 scfm. The overall average unit valve leak rate between the
two test engines was 4.48 +0.91 scfm. As with the rod leak rate measurements, variability in the
unit valve measurements was assessed using the student t test. The blowdown volume is constant
(9,200 scf/event) because the operating pressure and equipment volume remained the same.
3.2.2 Miscellaneous Fugitive Sources
Once each trip, miscellaneous fugitive emission sources were soap screened to identify
components that were leaking significantly and in need of leak-rate measurement. Seven
screenings were conducted on each engine. The types of components screened include:
• Valves, meters, pipes, and flanges
• Miscellaneous fittings (tees, elbows, couplings, drains, ports, small valves)
• Blowdown gas recovery system components
The soap screening revealed no leaking components. This is not surprising, because most of
these components are located in confined working areas, and any leaks could result in a
significant safety hazard or triggering of the gas detection alarm system located at the site.
3-8
-------
Table 3-3. Component Leak Rates
Date
Blowdown
Valve, scfm
natural gas
Pressure Relief
Valve,
scfm natural gas3
Unit Valve,b
scfm natural
gas
Blowdown
Volume,0
scf natural
gas/event
ENGINE 801
7/15/99
0.00
0
3.31
9,200
8/4/99
0.00
0
6.22
9,200
8/5/99
od
0
6.46
9,200
8/6/99
od
0
5.39
9,200
9/21/99
0.00
0
6.03
9,200
12/9/99
od
0
6.06
9,200
1/26/00
od
0
4.78
9,200
801 Average
na
na
5.46
na
801 Standard
Deviation
na
na
1.11
801 Confidence
Coefficient'
na
na
+1.03
na
ENGINE 802
7/16/99
0.00
0
2.82
9,200
8/4/99
0.00
0
5.49
9,200
8/5/99
0d
0
5.00
9,200
8/6/99
0d
0
4.20
9,200
9/22/99
0.00
0
2.43
9,200
12/8/99
0d
0
1.99
9,200
1/25/00
0d
0
2.50
9,200
802 Average
na
na
3.49
na
Standard
Deviation
na
na
1.39
802 Confidence
Coefficient1
na
na
±1.29
na
802 Overall
Average
na
na
4.48
na
Overall
Standard
Deviation
na
na
1.58
Overall
Confidence
Coefficient'
na
na
+0.91
na
3 Zero leak rates are assigned because screening with a hydrocarbon analyzer did not detect
measurable levels.
b Represents total leak rates from both unit valves on the engine.
c Based on calculations performed by ANR engineers. This value represents the total volume of
gas present in the test compressor, piping, and all equipment located downstream of the unit
valves (at 700 psig).
d Zero values were assigned based on previous measurements.
e Student t distribution statistical analyses were used. Results are reported at 95% confidence level,
na Not applicable
3-9
-------
3.3 NET GAS SAVINGS
The primary verification parameters for the Phase II evaluation are annualized gas savings and
payback period. Both are based on the net gas savings measured throughout the Phase I and II
testing. The Phase II test period began on September 21, 1999, after about 1,200 hours of
operation on Engine 801 seals and about 1,500 hours on 802. Phase II testing ended on the last
day of sampling (January 27, 2000). Net gas savings for the entire test period were calculated for
the Case 1 and Case 2 baseline shutdown scenarios based on the engine specific average leak
rates presented in Sections 3.1 and 3.2 and engine operational data presented in the next section.
3.3.1 Compressor Operational Characteristics
To calculate net gas savings for the verification period, the operational characteristics of both
engines were determined on a daily basis. These operating characteristics include the number of
shutdowns, the number of hours in the idle mode, and the number of hours in the running or
operating mode. These operating characteristics, presented in Appendix B, were defined for
Engines 801 and 802 using data supplied by ANR Pipeline. All periods when the station was off-
line or the engines were in the out-of-service mode (i.e., non-idle-mode such as maintenance and
repair) were not included in the determination of gas savings. The gray areas in the table
correspond with sampling conducted by the Center, and operating or idle periods on these days
are also not included in the verification. Although several engine shutdowns occurred on these
days, they are not included in the determination of gas savings because these shutdowns were
performed at the request of the Center. During the Phase I and II test period, Engine 801 was idle
about 32 percent of the time, while Engine 802 was idle about 23 percent of the time.
3.3.2 Case 1 and Case 2 Gas Savings During the Verification Period
This section presents calculated gas savings associated with the Cook Static-Pac for Engines 801
and 802. Savings are computed by comparing compressor rod leak rates when the Static-Pac is
installed, with compressor rod leak rates without the Static-Pac. The Static-Pac requires that a
pressurized shutdown/idle mode is used, and the shutdown and idle mode operations used prior to
installing the Static-Pac will affect the gas savings achieved. As discussed in Section 3.1, it was
determined through direct measurement of uncontrolled emissions that leak rates on the Control
Rods were significantly lower than the industry average. This issue will be addressed in Sections
3.5 and 3.6 where annual gas savings and payback periods are presented.
Two base-case compressor standby operating modes are evaluated. Case 1 represents the original
use of a pressurized shutdown (same as Static-Pac requires), and Case 2 represents the original
use of compressor depressurization and blowdown practice. As a result of changing the packing,
and possibly the shutdown/idle mode, a variety of emission changes will occur in both cases.
Each change is quantified here, and the bullets below describe how each value is determined.
The emission factors referred to below were described in Sections 3.1 and 3.2, and are
summarized in Table 3-4.
3-10
-------
CASE 1 (no change in shutdown/idle mode; i.e., pressurized shutdown practice continues):
• Rod seal savings while idle:
Description: Rod packing leaks that are reduced by the Static-Pac during idle periods
Calculation: Idle hours*(Control Rod leak rate - Test Rod leak rate)
CASE 2 (change from blowdown mode to a pressurized mode):
• Rod seal leaks increase while idle:
Description: Idle-mode rod packing leak rates from Static-Pac (with new pressurized
shutdown/idle mode, these leaks, although very low, must now be added)
Calculation: Idle hours*(Test Rod leak rate)
• Blowdown volume savings:
Description: Gas contained in the compressor and piping released during shutdown (with
new pressurized shutdown/idle mode, these emissions are no longer released)
Calculation: Number of shutdowns*(blowdown volume emission factor)
• Blowdown valve emission increases:
Description: Gas released from the closed blowdown valve (with new pressurized
shutdown/idle mode, these emissions must now be added)
Calculation: Idle hours*(blowdown valve leak rate)
• Unit valves leak savings:
Description: Gas released from the closed unit valves (with new pressurized
shutdown/idle mode, these emissions are no longer released)
Calculation: Idle hours*(unit valves leak rate)
• PRV and miscellaneous component losses
Description: Gas released from the pressure relief valve and miscellaneous fugitive
sources (with new pressurized shutdown/idle mode, these leaks must now be added)
Calculation: Idle hours*(PRV + Miscellaneous component (leak rates)
Table 3-4. Average Leak Rates Used to Compute Gas Savings
(scfm natural gas)
Engine 801 Control Rod ,die/nressur,zed
0.610
Engine 802 Control Rod ldie/PreSSunzed
0.452
Engine 801 Test Rod idle/pressurized
0.020
Engine 802 Test Rod idle/pressurized
0.017
Blowdown Volume
9,200 scf / shutdown event
Blowdown Valve
0.00
Unit Valve
4.48
Pressure Relief Valve and Misc.
Components
0
Tables 3-5a and 3-5b present the actual Case 1 and 2 gas savings, respectively, that occurred
during the entire verification test period from July 15, 1999, to January 27, 2000. Gas savings
were calculated using average leak rates summarized in Table 3-4 and the engine operating data
3-11
-------
for the period as summarized in Appendix B. The Case 1 and Case 2 savings are reported on a
per engine basis assuming that Static-Pacs are applied to each of the two engine's compressors.
Total natural gas savings for both engines under Case 1 were calculated to be 148,780 scf of
natural gas, or savings of about 31 scf natural gas/standby hour for each Test Rod. These gas
savings occurred because the Static-Pac reduced emissions by 96 percent during idle mode and
the engines averaged 28 percent idle time during the verification.
Total natural gas savings for both engines under Case 2 were calculated to be 1,129,603 scf of
natural gas. For this case, changing from a base case or blowdown practice to a pressurized
condition resulted in significant gas savings from the blowdown volume and unit valves (Table 3-
5b). However, the change in operating practice also resulted in emission increases from other
components now exposed to high pressures. This includes packing leaks from the Static-Pac
equipped rod. With the Static-Pac, some leaks are occurring from the engaged Static-Pac, but it
is still inhibiting higher leak rates (total of 148,780 scf) that would have occurred if it was not
installed.
Table 3-5a. Case 1 Gas Savings for the Test Period
(scf natural gas)
CASE 1
Rod Seal Savings
While Idle
Rod Seal Increases
While Running
Total Savings
Engine 801
97,107
0
97,107
Engine 802
51,673
0
51,673
Total
148,780
0
148,780
Table 3-5b. Case 2 Gas Savings
(scf natural gas)
Gas Savings Due To Change From Blow-Down Mode To Pressurized Mode
Blow-
down
Volume
Savings
Unit Valve
Leak
Savings
Blowdown
Valve Emission
Increases
Pressure Relief Valve
And Misc. Comp.
Increases
Rod Seal Increases
(Static-Pac Installed
and Engaged)3
Total
Savings Minus
Emission
Increasesb
Engine
801
257,600
362,853
0
0
-3,078
617,375
Engine
802
248,400
266,085
0
0
-2,257
512,228
Total
506,000
628,938
0
0
-5,335
1,129,603
Note: Base case scenario is defined as a compressor that changes from a blowdown practice to a pressurized practice.
a The rod packing continues to leak slightly with the Static-Pac installed, but it is still inhibiting higher leak rates that would have
occurred if the Static-Pac was not installed. Had Static-Pac not been installed, an additional increase of 154,115 scf of natural gas
would be liberated.
b Total gas savings are a result of elimination of blowdown and unit valve releases, not the Static-Pac. The rod seal increases emissions
slightly because it is now exposed to pressurized conditions. However, the increase with the Static-Pac is lower than the increase
without the Static-Pac.
3-12
-------
From a greenhouse gas emissions standpoint, the natural gas savings and emission increases cited
above were converted into methane savings/increases by using natural gas compositional data
routinely measured by ANR pipeline (Section 2.3.2.3). An average methane composition of
97.28 percent was measured during the Phase I and II test periods by ANR and, based on this
value, total methane savings were:
Case 1: Net methane decrease of144, 733 scf for both engines
Case 2: Net methane decrease of 961,216 scf from eliminating the blowdown practice and not installing a
Static-Pac, and net methane decrease of 1,098,878 scf from eliminating the blowdown practice
and installing a Static-Pac.
3.4 ANNUAL GAS SAVINGS
3.4.1 Annual Case 1 and Case 2 Gas Savings
One of the goals of the Phase II testing was to calculate the gas savings associated with the use of
the Static-Pac on an annual basis. Section 2.3.1.4 discussed in detail the procedures used for this
determination. As mentioned, the data collected during Phases I and II of this verification
indicated that there was no trend in increases in idle mode emissions over time as initially
expected. Therefore, the conservative approach was used in annualizing gas savings by using the
engine-specific average control rod leak rates minus the average emission rates from the Static-
Pac observed throughout the entire test period. This average gas savings rate was used to
calculate annual savings for an engine with two compressor rods equipped with the Static-Pac by
multiplying it by the expected number of idle hours during a typical calendar year.
Table 3-6 summarizes the running and idle hours for the 1999 and early 2000 operating period.
Also included in the table is the total number of shutdowns logged for each engine.
Table 3-6. Operating and Idle Hours for Engines 801 and 802 - 1999/2000
Month
Engine 801
Engine 802
Running
Idle
Shutdowns
Running
Idle
Shutdowns
February
442
230
3
345
327
2
March
661
83
0
282
462
3
April
159
561
1
262
458
3
May
159
585
3
262
482
3
June
618
102
1
236
484
1
July
572
172
1
440
304
1
August
418.6
190.7
6
526.5
83.8
5
September
430
218
2
572.2
75.8
3
October
605
91
6
583
113
5
November
425
295
6
614
106
6
December
586.1
85.9
3
394.7
277.3
3
January
164.6
411.4
34
412.7
163.3
3
Total
5240.3
3025
35
4930.1
3336.2
38
Percent of
Total
63.4
36.6
59.6
40.4
3-13
-------
The data do not include periods of station shutdowns, engine maintenance, or verification testing.
All data were obtained from ANR records.
Engines 801 and 802 averaged approximately 63.4 and 59.6 percent operating time, respectively,
corresponding to an overall average idle time for both engines of 38.5 percent. The two engines
averaged 37 shutdowns during the 12-month period. Using the average idle time of 38.5 percent,
each rod would average a total of 3,373 idle hours per year. The annual gas savings for Case 1
and Case 2 operating scenarios are summarized in Tables 3-7a and 3-7b, respectively. Briefly,
the Case 1 annual savings are 204,000 scf per engine or 102,000 scf per compressor rod. The
Case 2 annual savings are 1,239,372 scf per engine. It should be noted that the majority of the
Case 2 savings are due to the elimination of blowdown volume and unit valve emissions, not the
Static-Pac.
TABLE 3-7a. Annual Gas Savings for Case 1 (February 1999 to January 2000)
(scf natural gas)
CASE 1
Rod Seal Savings
While Idle
Rod Seal Increases
While Running
Total Savings
Engine With Two Compressor Rods Equipped
With Static-Pac s
204,000
0
204,000
Table 3-7b. Annual Gas Savings for Case 2 (February 1999 to January 2000)
(scf natural gas)
Gas Savings Due To Change From Blowdown Mode To Pressurized Mode
Blowdown
Volume
Savings
Unit Valve
Leak
Savings
Blowdown
Valve
Emission
Increases
Pressure Relief
Valve And Misc.
Comp. Increases
Rod Seal
Increases
(Static-Pac
Installed and
Engaged)3
Total
Savings Minus
Emission
Increasesb
Engine with two
compressor rods
equipped with
Static-Pac s
340,400
906,662
0
0
-7,690
1,239,372
Note: Base case scenario is defined as a compressor that changes from a blowdown practice to a pressurized practice.
a The rod packing continues to leak slightly with the Static-Pac installed, but it is still inhibiting higher leak rates that would have
occurred if the Static-Pac was not installed. Had Static-Pac not been installed, an additional annual increase of 211,690 scf natural gas
would be liberated.
b Total gas savings are a result of elimination of blowdown and unit valve releases, not the Static-Pac. The rod seal increases emissions
slightly because it is now exposed to pressurized conditions. However, the increase with the Static-Pac is lower than the increase
without the Static-Pac.
3-14
-------
3.4.2 Estimated Annual Gas Savings For Other Compressors and Engines
The natural gas emission rates encountered at the test site were lower than the typical emission
rates reported for rod packing leaks in the natural gas industry. Specifically, an EPA/GRI study
reported an average leak rate of about 0.9 scfim per rod (Hummel et al., 1996). A study conducted
by the Pipeline Research Committee (PRC) reported an average leak rate of about 1.9 scfim per
rod (GRI 1997). These studies suggest that rod leak rates can vary significantly from one site to
another and that the compressor leak rates tested under this verification are atypical. For this
reason, the rod leak rate data collected under this verification program are believed to represent
sites with low leak rates, and additional gas savings could be achieved for rods with industry
average leak rates. To provide results more useful to the industry, annual gas savings for rods
exhibiting industry average leak rates are estimated.
The measurements data collected during the test provide an understanding of Static-Pac
performance for a range of rod leak rates, and allow extrapolation of measured data to industry
average leak rates. The uncontrolled rod leak rates encountered at the site ranged between 0.23
and 1.13 scfim. The data collected clearly show that emissions from Static-Pac equipped rods do
not vary over the range of uncontrolled emission rates observed at the site. As shown in Table 3-
1 and Figure 3-1, the Static-Pac performance was relatively consistent, with emission reductions
ranging from 89.5 to 99.1 percent (average reduction of 96 percent). Based on this, it is
reasonable to assume that rods leaking at the GRI published industry average leak rate of 0.9
scfim are likely to achieve a 96 percent reduction in emissions.
Direct measurements data were not available for the PRC published industry average leak rate of
1.9 scfim. The highest uncontrolled leak rate measured at the site was 1.13 scfim, and the emission
reduction associated with this leak rate was 99.1 percent. This one data point does not indicate
performance output at the PRC reported leak rate. However, a plot of leak rate versus emission
reduction (see Figure 3-3) clearly shows that Static-Pac leak reduction potential continues to
improve at higher leak rates. For the PRC reported leak rate, it is assumed this trend continues,
and the 96 percent emission reduction verified during the test can be extrapolated to the 1.9 scfim
industry average leak rate. The reader is cautioned with limitations with this assumption because
it is based on observed trends in the data.
3-15
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Figure 3-3. Emission Reduction Performance at Varying Rod Leak Rates
l«Enareeoi •ErxnsSCel
4
~
~
•V
• ~
t
90 92 94 96 98 100
Emission Reduction (%)
Different compressor stations will also vary in average annual engine standby times. To account
for such variability, annual gas savings were estimated for two engine standby rates: the rate of
38.5 percent that was determined during this test, and the rate of 55 percent that was cited as the
average in the GRI study (Hummel et al., 1996). The number of compressors on an engine can
also affect gas savings and payback. The test engines were equipped with only two compressor
rods. The average number of compressor rods per unit tested in the PRC study was 3.3 (GRI
1997).
In the annual gas savings matrix presented in Table 3-8, annual gas savings are estimated for each
of these variations in idle time and number of compressors using each of the varying rod leak
rates referenced above (0.523, 0.9, and 1.9 scfm). The matrix assigns a Static-Pac emission
reduction rate of 96 percent to each of the rod leak rates. The intent of the matrix is to provide a
representative assessment of Static-Pac performance based on leak rates and engine operational
data documented by the gas transmission industry at a wide range of gas processing facilities.
3-16
-------
Table 3-8. Case 1 Annual Gas Savings Matrix for Varying Rod Leak Rates
and Engine Idle Periods
Conventional
Packing Case Leak
Rate (cfm Natural
Gas)
Annual Natural Gas Savings per Engine (Mscf)b
2 Compressors per Engine
3 Compressors per Engine
38.5 % Idle
55 % Idle
(Industry Avg.)
38.5 % Idle
55 % Idle
(Industry Avg.)
0.523
(Test Site)
204a
290
305
435
0.9
(GRI Industry
Average)
350
500
525
749
1.9
(PRC Industry
Average)
738
1,055
1,107
1,582
a Actual gas savings measured during this verification
b Mscf = thousand standard cubic feet
3.5 STATIC-PAC PAYBACK PERIOD
3.5.1 Capital, Installation, and Operation and Maintenance Costs
Table 3-9a presents the equipment and labor costs for the Control Rod packing material and all
costs related to the Static-Pac system. These costs were obtained from C. Lee Cook and station
operators. On a per-rod basis, the capital cost for the Static-Pac system was $4,088 in 1999. This
is about $2,638 higher than the conventional packing case installed on the Control Rod. The
Static-Pac system required 48 hours to install on each Test Rod (about 13 hours more than the
Control Rod). Installation of the Static-Pac seals was similar to that of a conventional packing
case, with the exception that the conventional packing case is modified to accept Static-Pac
components. This involves milling/modifying the last cups to enable the Static-Pac seals and
piston apparatus to be accommodated in the packing case. The costs associated with this activity
(5 labor hours) are a one-time requirement that are accrued as a result of upfitting a conventional
packing case. This task is not repeated during routine maintenance and operation, because the
packing case is already modified to accept replacement Static-Pac seals. In addition to this, an
automatic activator system is installed to provide pressurized gas to the piston. The installation
and operating procedures, as submitted by C. Lee Cook, are provided in Appendix C as a
reference. No deviations from these procedures were observed in the field.
Based on the data presented in Table 3-9a, the difference in costs for a rod equipped with the
Static-Pac and a rod equipped with a conventional packing case is $3,483 for an engine with one
compressor rod and one system actuator. The engines tested have two compressors and rods.
Normally, Static-Pacs would be installed on both rods and be controlled by one common actuator
at a cost of $4,808. This scenario is applicable to the host site and is used to calculate payback.
The industry average for number of compressors on a single engine is three. This scenario (one
3-17
-------
actuator and three rods equipped with Static-Pacs) has a cost increase of $6,133 and is also used
to estimate payback.
Table 3-9a. Static-Pac Equipment and Installation Costs
Test Rod
Control Rod
Increase in Packing
Case Cost for
Upgrading to a Static-
Pac
$ / rod
Description
Cost
$
Description
Cost
$
Capital Equipment
Packing Case with
Static-Pac
2,200
Conventional
Packing Case
1,450
750
Automatic Actuator
System
1,638
-
-
1,638
Miscellaneous
Materials
250
-
-
250
Installation Labor
Packing Case With
Static-Pac
2,600a
(40 hrs)
Conventional
Packing Case
2,275a
(35 hrs)
325
Actuator System
520a
(8 hrs)
-
-
520
Total Capital Cost
$7,208
$3,725
$3,483
a Installation costs of $65 per hour are assumed.
Note: For multiple rod installations, only the costs for packing case and miscellaneous materials are increased by the
number of rods (i.e., actuator costs remain the same).
Static-Pac Operation and Maintenance (O&M) cost assumptions are based on observations at the
ANR host site and discussions with two other ANR operators. Table 3-9b contains a summary of
O&M cost findings for the three ANR sites which collectively represent a history of 57 Static-
Pacs operating between 1 and 16 years. No repairs, replacement parts, or maintenance were
needed on either of the Static-Pac systems tested throughout the test period. In addition,
discussions with ANR operators at two other sites indicate that O&M costs for the Static-Pac
were negligible for representative compressors experiencing normal operation. Specifically, 83
percent of the Static-Pacs installed experienced negligible O&M costs. Based on this and
similarities observed between the three sites, annual O&M costs for the test site are assumed to be
negligible.
The remaining 17 percent of the Static-Pacs installed at the two sites were found to require
replacement parts in the latter years, mostly due to malfunctioning compressors. It is likely that
other factors are causing this, but sufficient information was not available to form definitive
conclusions. This small population of compressors are included in the payback analyses using
O&M cost findings reported in Table 3-9b. For rods that begin to misalign, excessive wear in the
packing case seals can occur. Under these conditions, any worn or damaged conventional seals
and the last two Static-Pac seals are usually replaced. The capital costs for a one-time
replacement are reported to range from $500 to $800/rod. Both site operators reported that these
costs occurred in years 10 through 15. No additional labor costs were reported by ANR operators
because replacing the Static-Pac seals required the same amount of time as replacing
3-18
-------
conventional packing seals that would be present if the Static-Pac was not there. The payback
calculations assume that O&M costs are negligible in years 1 through 10 and increase to
$160/rod/yr for years 11 through 15 (average of the $800 figure over a 5-year period).
The Static-Pac O&M cost assumptions outlined above are considered representative of ANR type
facilities. The reader is cautioned to use these data for unrepresentative compressors, and is
encouraged to apply their site specific cost assumptions to develop payback estimates.
Table 3-9b. Summary of Findings for Static-Pac Operation and Maintenance Costs
ANR Test Site
ANR Defiance Station
ANR Meade Station
No. of Static-Pacs In Place
2
36
29
Age of Static-Pacs In Place
1 yr
15 yrs
15 yrs
Routine Inspection Costs
Static-Pac inspection
conducted
simultaneously with
other seals in packing
case; no additional
labor hours expended
Static-Pac inspection conducted
simultaneously with other seals in
packing case; no increase in labor
was reported
Static-Pac inspection conducted
simultaneously with other seals in
packing case; no additional labor
hours expended
Parts Replacement Costs
No O&M costs
occurred
For about 6 Static-Pacs
Year 1-10: O&M costs were
"essentially negligible3"
Year 11-15: one time cost of
$600/rodc
For 5 Static-Pacs
Year 1-10: 0 to $1.60/yr/rodb
Year 11-15: one time cost of
$500 to $800/rodc
For remaining 30 Static-Pacs
Year 1-15: O&M costs were
"essentially negligible8"
For remaining 24 Static-Pacs
Year 1-15: 0 to $1.60/yr/rodc
Proposed O&M Cost
Factors for Payback
Calculations
Paybacks will be discussed for 2 scenarios:
• Well maintained, properly functioning compressors: costs are negligible
• Compressor rods that malfunction: Year 1-10 costs are negligible; Year 11-15 costs are
$160/rod/yr
a Site operators defined negligible as being so small that records were not maintained
b Consists of $1.50 for springs and $0.10 for O-rings. Site reports that these parts were replaced as a precautionary measure, not
because of failures in Static-Pac components
c Due to compressor malfunctioning, damage to Static-Pac seals occurred. New Static-Pac seals were added at the same time
new conventional seals were replaced.
3.5.2 Payback Period for the Test Engines
Payback was determined for Case 1 only, which represents compressors that normally maintain
full operating pressure during idle periods. Payback for Case 2 was not determined due to
concerns raised by several peer reviewers. The reviewers indicated that readers could
inappropriately associate all of Case 2 savings to the Static-Pac, where in actuality, significant
savings are occurring due to a change in the operating practice (i.e., converting from blowdown
practice to pressurized conditions). Using the equations specified in Section 2.3.1.4, the
annualized gas savings measured at the test facility, the initial costs outlined in Table 3-9a, and
O&M costs assumptions discussed above, the Case 1 payback period is greater than 30 years for
the test site.
3-19
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3.5.3 Payback Period for Other Compressors and Engines
As mentioned earlier, uncontrolled rod leak rates at this facility were much lower than industry
averages. Thus, the economic performance for a low-emitting site that remains pressurized is not
favorable, but acceptable paybacks can be achieved for sites with industry average leak rates. In
order to determine Static-Pac payback period for more typical facilities, the same data sources
used to estimate potential gas savings (Section 3.4.3) were used to develop Table 3-10. All of the
payback periods were calculated using the procedures presented in Section 2.3.1.4 and include the
10 percent discount rate of return on capital. These tables summarize potential payback periods
for each of the gas savings scenarios presented in Table 3-8.
Table 3-10. Case 1 Payback Period Matrix
Conventional
Packing Case Leak
Rate (cfm Natural
Gas per Rod)
Payback Period (years)
2 Compressors per Engine
3 Compressors per Engine
38.5 % Idle
(Test Site)
55 % Idle
(Industry Avg.)
38.5 % Idle
(Test Site)
55 % Idle
(Industry Avg.)
0.523
(Test Site)
>30a
18.5
>30
12.8
0.9
(Industry Avg.)
12.2
6.9
9.2
5.5
1.9
(Industry Avg.)
4.1
2.7
3.4
2.3
a Actual payback estimated for test site
As shown in Table 3-10, the Case 1 payback period can vary significantly depending on an
engine's standby rate, rod packing leak rates, and number of compressors. The extremely low gas
leak rates measured at the test facility, combined with the assumed 10 percent rate of return
discount on capital, make payback essentially unattainable under those conditions. However,
with higher leak rates more typical of conventional rod packing, reasonable payback periods can
be achieved depending on average engine idle times. A payback period of less than 4 years can
be achieved when the rod leak rates are near the PRC-reported industry average of 1.9 scfm and
the engine standby rate is greater than 38 percent. If these compressor rods require Static-Pac
replacement parts as stated in the O&M cost discussion, the payback period increases by about 3
months. The user is cautioned that gas savings associated with this leak rate are based on
extrapolation of measured data, and potential for alternate gas savings exists. This means that
payback estimates for the 1.9 leak rate could be lower or higher than the values reported in Table
3-10.
3-20
-------
3.5.4
Limitations to the Verification Conclusions
In the Phase I report, the Center reported that the continuous emissions monitoring originally
planned for this verification could not be conducted because of the low leak rates encountered at
the test site. In lieu of continuous measurements, the Center increased the number of manual
measurements to achieve a larger data set. Nevertheless, the data set collected is much smaller
than originally planned. In addition to the small data set, uncontrolled leak rates at the test
facility were somewhat atypical when compared to the industry average in that they were much
lower than emissions documented for many other gas transmission stations.
Because the uncontrolled rod packing leaks at the test site were low, the calculated emission
reductions achieved by the Static-Pac were also low. As explained earlier, the percent decrease in
emissions measured at the test site was extrapolated to apply to average compressor emissions
documented in other studies. The data collected during this study showed that emission
reductions were steady throughout the range of uncontrolled leak rates measured. In most cases,
emission reductions were highest when uncontrolled emissions were highest because emissions
with the Static-Pac engaged did not increase proportionally to uncontrolled emissions. It was on
this basis that the data were extrapolated to the industry average. However, since no actual
measurements were conducted at the higher industry average leak rates, and the data set presented
in this report is much smaller than originally planned, the payback periods presented in the
payback matrix are estimates only.
3-21
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4.0 DATA QUALITY
4.1 BACKGROUND
Information on data quality is used to characterize the level of uncertainty in measured values and
verification parameters. The process of establishing data quality objectives starts with
determining the desired level of confidence in the primary verification parameters. A primary
parameter was the establishment of idle-mode gas savings for the Static-Pac. These gas savings
were used to help quantify the primary Phase II verification parameter which is the Static-Pac
payback period. The data quality objective that was established for the payback period is based
on input from gas industry and other Stakeholder Group members and allows for an error in
payback values of about +3 to 4 months, or approximately 10 percent of a favorable payback
period of 3 to 4 years. This objective was used to set data quality indicator goals for the
following key measured values: rod packing emissions; valve emissions (unit, blowdown, and
pressure relief valves); miscellaneous source emissions; and natural gas quality measurements.
This section identifies the data quality indicator goals and discusses whether they were met to
satisfy the data quality objectives.
Table 4-1 summarizes the data quality indicators assigned for primary measurement variables.
Throughout the test period, field and laboratory measurements were collected in an effort to
quantify instrument and sampling errors associated with these measured values. For example, the
accuracy and precision of the Flow Tube measurements were quantified with frequent
calibrations and replicate samples, and these data were used to quantify uncertainty in the rod
packing emission rates. The resulting data sets were analyzed to determine if significant
variability was present. The instrument calibrations and replicate sample results, along with
accuracy and precision data provided by instrument vendors, were used to determine if the data
quality indicator goals were met, and thus, the data quality objective was satisfied. The following
subsections discuss the data quality assessment of the primary measurement variables, and the
overall uncertainty associated with the final results.
4.2 ROD PACKING EMISSION RATE MEASUREMENTS
The continuous flow metering devices initially planned for use on the doghouse vents did not
function properly in the field. As a result, these meters were replaced by manual Flow Tube
measurements. The maximum instrument error anticipated for the Flow Tube was +2 percent
according to manufacturer specifications. The error due to sampling (i.e., configuring the
anemometers inside the flow tube) was established through laboratory calibration of the Flow
Tube. A combined error of 5 percent was anticipated, which would have allowed the
achievement of the data quality objectives set for the payback period. The error due to variability
encountered in the process (i.e., rod leak rate for each compressor) was not addressed in the Test
Plan because such data were not available to establish reasonable bounds. The uncertainty
associated with the process was discussed in Section 3.0. The following paragraphs discuss
whether data quality indicator goals (i.e., accuracy, precision, completeness) were met, and how
these affected the overall quality of the Static-Pac performance data.
4-1
-------
Table 4-1. Data Quality Indicator Goals
Measurement
Method
Range
Instrument and
Sampling Error
How Determined
Frequency
Goal
Accuracy
Precision
Rod Packing
(Doghouse
Vent)
Emissions
Flow Tube
with Vane
Anemometer
0.20 to 3.0
scfm
0.18 scfm
10%
Calibration against
certified laminar
flow element
90 % of
hourly data
over test
period
Flow Tube
with Thermal
Anemometer
0.02 to 0.10
scfm
0.006
scfm
20%
Calibration against
certified laminar
flow element
Unit Valve
Leak Rate
Flow Tube
with Vane
Anemometer
0.30 to 6.0
scfm
0.36 scfm
10%
Calibration against
certified laminar
flow element
9 Repetitions
Leaks From
All Other
Components
THC
Detector
Dual range:
0.05 to 4.0 %
4 to 100 %
2 % of
reading
Not
Specified
Certified
Calibration Gases
9 Repetitions
Four Flow Tubes were used to measure rod leak rates during the testing. Three of these were
vane anemometers (two were damaged during testing and replaced by new anemometers) and the
fourth contained the low-flow thermal anemometer. The Flow Tubes were calibrated with a
laminar flow element (LFE), which itself was calibrated with an NIST-traceable primary
standard. Table 4-2 summarizes calibration results for the Flow Tubes, and shows the accuracy
and precision values developed from these data.
The average Flow Tube accuracy values presented for each run were calculated from the
individual measurements in a run. Each run consisted of a series of comparisons at five or six
different flow rates ranging from 0 to 3.0 scfm methane (see Figure 4-1 for an illustration of a
calibration curve for the vane anemometer). Individual measurement accuracy values were
calculated by determining the absolute value of the difference between the Flow Tube and LFE
flow rates (Flow Tube minus LFE), and averaging this value over the rates of each calibration
run. As the table shows, the average accuracy of the Flow Tubes equipped with vane
anemometers ranged from 0.012 to 0.086 scfm. The overall average accuracy with regards to
sampling error for all three tubes used was 0.040 scfm, or 1.35 percent of the calibration range.
4-2
-------
Table 4-2. Summary of Flow Tube Calibrations (Low Flows)
Calibration
Flow Tube
Calibration
Calibration Range
Accuracy
Precision
Date
ID
Run No.
(scfm)
(scfm)
(%)
6/2/99
ID-1
1
0.34 to 2.75
0.036
0.24
Vane
2
0.34 to 2.75
0.037
7/2/99
ID-1
1
0.35 to 3.47
0.028
0.66
Vane
2
0.36 to 3.46
0.037
7/23/99
ID-1
1
0.38 to 2.75
0.031
2.8
Vane
2
0.38 to 2.75
0.049
8/11/99
ID-1
1
0.39 to 2.69
0.037
0.23
Vane
2
0.39 to 2.69
0.038
8/11/99
ID-2
1
0.18 to 1.55
0.086
0.87
Vane
2
0.18 to 1.55
0.012
11/9/99
ID-3
1
0 to 1.63
0.032
0.07
Vane
2
0 to 1.63
0.020
12/10/99
ID-3
1
0 to 1.63
0.052
0.12
Vane
2
0 to 1.63
0.048
2/2/00
ID-3
1
0 to 2.42
0.038
0.09
Vane
2
0 to 2.67
0.066
12/13/99
Thermal
1
0 to 0.08
0.0049
1.5
2
0 to 0.07
0.0029
1/21/00
Thermal
1
0 to 0.10
0.0029
4.8
2
0 to 0.10
0.0022
2/2/00
Thermal
1
0 to 0.09
0.0015
3.6
2
0 to 0.08
0.0040
2/24/00
Thermal
1
0 to 0.10
0.0007
1.9
2
0 to 0.10
0.0015
The calibration curves for the thermal anemometer are not linear, but when the nonlinear
calibration is applied, average accuracy over the calibration range was 0.0026 scfm,
corresponding to 2.6 percent of the calibration range. Because the thermal anemometer was used
to measure only extremely low flow rates in the range of 0.01 to 0.03 scfm, the sampling errors
corresponding to these rates are very small. The thermal anemometer was first used in the field in
September 1999, but was not calibrated prior to that sampling episode. The calibration curve
from the December calibration was used for the September tests. This was considered acceptable
after documenting that the calibrations are very consistent through February 2000 and measured
flow rates (with Static-Pac engaged) were also consistent throughout the test period.
Conducting two replicate calibrations each time the flow tubes were calibrated assessed precision
and/or repeatability. The calibration curves developed from replicate calibration series were
compared at several velocity readings over the calibration range. Precision is calculated as the
average of the CV (coefficient of variation which, for paired measurements, is equivalent to 0.707
4-3
-------
times the absolute value of the difference divided by the mean value of the pair) at each of the
velocity values for the run. Figures 4-1 and 4-2 are examples of Flow Tube calibrations
Figure 4-1. Flow Tube Calibration - Vane Anemometer
Serial No: 40-90-09690
3.00
2.50
y = 0.0034X - 0.0334
R2 = 0.9974
2.00
E
4—
o
to
V = 0.0034X - 0.0307
Ft = 0.996
u_
1.00
0.50
0.00
0
100
200
300
400
500
600
700
800
900
Gas Velocity (fpm)
X
2/2/00 run 1
~
2/2/00 run 2
—
Linear (2/2/00 run 1)
Linear (2/2/00 run 2)
Figure 4-2. Flow Tube Calibration - Thermal Anemometer
Serial No: 91070385
0.10
0.08
0.06
0.04
0.02
X 1/21/00-1
~ 1/21/00-2
Poly. (1/21/00-1)
Poly. (1/21/00-2)
y = 9E-06X + 0.0002X
R2 = 0.9898
40 50 60
Gas Velocity (fpm)
y = 9E-06X1 + 0.0003X
R2 = 0.9996
4-4
-------
with both a vane anemometer (Figure 4-1) and a thermal anemometer (Figure 4-2). Through
previous laboratory tests conducted by the Center, it has been determined that the precision using
two calibration curves is similar to precision results that would be obtained with three separate
calibration curves. The calibration results indicate that close agreement between replicate
readings can be achieved and show the close agreement of example replicate calibration runs. The
means of the precision values in Table 4-2 are 0.64 percent for the vane anemometer runs, and
2.95 percent for the thermal anemometer runs.
In conclusion, the data quality indicator goals for accuracy and precision were met for all rod leak
rate measurements.
Similar to the Phase I test, the original completeness goal for rod packing emissions
measurements required the completion of 90 percent of hourly measurements using continuous
flow monitoring throughout Phase II. As discussed in Section 3.1, continuous measurements
were not feasible, and an alternate method of manual sampling was used. The manual
measurement data collected during Phases I and II represent 14 days of sampling, and cover a 6-
month period. Clearly, the data set collected is much smaller than originally planned, and the
completeness goals were not met as a result of changing the sampling procedure from continuous
to manual sampling. Close examination of the data set collected reveals that emission reductions
due to the Static-Pac are relatively consistent for both Control rods, indicating that both
performance and emission rate variability over time are adequately captured in the data set.
Figures 3-1, 4-3, and 4-4 illustrate that, over a series of 13 to 16 different measurement samples
taken, a wide range of control rod emission rates were encountered. At each of these emission
rates, the test rod with the Static-Pac consistently reduced leaks by at least 90 percent. Further
sampling within these intervals would likely not alter verification conclusions.
3.00
2.50
O
c
o
'
tfl
E
LD
T3
Si
2.00
1.50
1.00
c
O 0.50
0.00
Figure 4-3. Compressor Rod Emissions Data
r 0.50
¦¦ 0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
¦¦ 0.05
¦¦ 0.00
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17
Measurement Series
1 Control Rod (801) ¦—
— - A- - Static-Pac (801) — X—
Control Rod (802)
Static-Pac (802)
4-5
-------
Figure 4-4 Emission Reduction Determinations For
Pacs
r
~ Engine 801
~ Engine 802
ii i i i i i i i
i
Measurement Series
4.2.1 Unit Valve, Slowdown Valve, and Pressure Relief Valve
The Test Plan specified using the Hi-Flow device and/or EPA's protocol tent/bag method for
manual testing of the blowdown valve, pressure relief valve, and unit valves. As discussed
earlier, the Center was unable to obtain a license in time to use the Hi-Flow device, and the
tent/bag procedure would not have provided the desired level of accuracy needed at this facility.
Therefore, measurements were made using the Flow Tube equipped with a vane anemometer. In
all cases, the data quality achieved with the Flow Tube was better than the 10 percent accuracy
and precision goals set for the Hi-Flow device. QA results for the three flow tubes used for these
measurements are summarized below. Data quality considerations for the estimated blowdown
volume are also discussed.
The pressure relief and unit valve leak rates were measured using the same Flow Tubes discussed
earlier. Because flow was not detected for any pressure relief valves, QA and calibration data are
not presented for them. For the unit valves, gas velocities higher than those measured during rod
leak measurements were recorded. For this reason, a high-flow calibration chart was developed
to convert measured gas velocities into natural gas flow rates. The same Flow Tube calibration
procedures described for the rod packing vent measurements were followed here, and the
calibration data developed at high flows are presented in Table 4-3.
4-6
-------
Table 4-3. Summary of Flow Tube Calibrations (High Flows)
Calibration
Date
Flow
Tube ID
Run No.
Calibration Range (scfm)
Accuracy
(scfm)
Precision
(%)
8/11/99
1
1
2.14 to 7.59
0.065
1.16
2
0.60 to 6.61
0.043
8/12/99
2
1
0.32 to 6.72
0.075
0.12
2
0.33 to 6.67
0.057
9/27/99
2
1
0.26 to 3.31
0.041
2.81
2
0.26 to 3.66
0.027
12/2/99
3
1
1.67 to 5.43
0.034
2.17
2
1.79 to 5.47
0.064
1/20/00
3
1
1.65 to 5.36
0.034
0.64
2
1.76 to 5.39
0.028
A high flow calibration chart, similar to the Flow Tube calibration chart presented in Section 2
for the rod packing vent measurements, is shown in Figure 4-5. The average Flow Tube accuracy
(0.047 scfm) and precision (1.38 percent) at high-flow regimes were found to be comparable to
the values observed at lower flow regimes. Figure 4-5 clearly shows that the natural gas flow rate
is linearly proportional to the gas velocity measured with the Flow Tube. The accuracy and
precision of the Flow Tube exceeded the goals set for high flows such as those encountered with
the unit valves. The completeness goal for the unit valve measurements was nine measurements
(three sets of three). Unit valve leak rate measurements were made on 3 consecutive days in
August 1999 and revealed little variability on consecutive days. Therefore, only one
measurement was made during every subsequent visit to the site (to minimize blowdown gas
losses) for a total of seven unit valve leak rate measurements. Further sampling within these
intervals or continuous sampling would likely not alter the average leak rates determined through
manual sampling.
4-7
-------
Figure 4-5. Flow Tube Calibration - Vane Anemometer at High Flows
Serial No: 40-98-11431/5960
8.00
7.00
6.00
y = 0.0033x-0.1391
R2 = 0.9993
5.00
4.00
y = 0.0033x-0.1488
R2 = 0.9999
3.00
2.00
1.00
0.00
0
500
1000
1500
2000
2500
Gas Velocity (fpm)
* 8/12 run 1
~ 8/12 run 2
Linear (8/12 run 1)
Linear (8/12 run 2)
The Flow Tube was originally planned for use on blowdown valve leaks as well. However, Phase
I field results suggested that the flow rates from the blowdown valve leaks were very low and
well below the detectable limits of the flow tubes. Therefore, a low-flow rotameter was used to
conduct measurements on the blowdown valves. Those tests indicated that the blowdown valve
leak rates were either zero or an extremely low level that was negligible with respect to the
verification goals. Additionally, the test location required separation of a flange that was very
labor intensive and had to be conducted using host facility resources. For these reasons, the
blowdown valve leak rates were measured only once during Phase II of the verification.
For the miscellaneous components such as flanges and valve stems, it was not possible to
effectively channel the leaking gas to the flow tube. For these types of fugitive sources, soap
screening was used to identify significant leaks and, when flow rate determination was needed,
EPA's protocol tent/bag method was planned for use. Since significant leaks were not found, the
tent/bag method was not applied, and the data quality information is not presented.
The average accuracy values presented here are used in Section 4.3 to assess how these measured
values may contribute to overall uncertainty in the natural gas savings estimated for Cases 1 and
2.
4.2.2 Gas Composition
Based on average gas compositional data supplied by ANR, the average methane concentration in
the natural gas for the Phase I and II testing was determined to be 97.28 percent. The average
was calculated based on daily average values that were provided for each day that testing was
conducted (14 total). The reported daily averages were a function of the readings made by ANR
at 4-hour intervals. The accuracy of these readings was determined by ANR using calibration
gases and was reported to be 0.12 percent.
4-8
-------
4.2.3
Slowdown Volume
Blowdown volume was quantified based on the volume of piping and manifolds in the
compressor system, and is accurate to within the piping specifications (assumed to be 100 percent
accurate). The unit pressure, which was measured at the station by ANR engine monitors, was
used to convert the calculated volume into a volume of natural gas at standard conditions.
Generally, the host site operated at about 600 psig suction pressure. Unfortunately, calibration
records for the pressure monitor are not maintained by ANR, so accuracy estimates for this
measured parameter could not be determined. However, the accuracy of the pressure sensor was
not required because the blowdown volume was calculated based on a typical suction pressure of
600 psig.
4.3 OVERALL UNCERTAINTY IN THE MEASUREMENTS, NET GAS SAVINGS, AND
METHANE EMISSIONS VALUES
The errors associated with key measurement variables for this verification were determined and
are summarized in Table 4-4. The data quality indicator goals listed in Table 4-1 address the
desired accuracy of the measurement instrumentation and sampling procedures. However, the
pretest accuracy goals do not incorporate errors associated with process variability. As discussed
in Section 3.1, variability analyses were conducted on all of the compressor rod and unit valve
leak rate measurements to account for process variability. The net measurement errors
summarized in Table 4-4 include the instrument/sampling errors and the process variability.
Reviewing the data in Table 4-4, it is clear that the sampling errors documented for the testing are
all well within the data quality objectives specified in the plan. For the control rod and unit valve
measurements, the total net errors were 15 and 20 percent, respectively when the process
variability is included.
Table 4-5 propagates the measured instrument/sampling error and process variability to obtain the
overall uncertainty in the primary verification parameters. The primary objective of the
verification was to determine the payback period with an uncertainty of 10 percent. Sampling
errors and process variability were propagated based on the verification parameters listed in Table
4-5. Specifically, the average errors (from Table 4-4) associated with each of the measurements
used to determine the verification parameters were totaled to determine the overall uncertainty
due to instrument error. These errors were then combined with the process variability to obtain
overall measurement uncertainty for each of the verification parameters.
4-9
-------
Table 4-4. Summary of Errors Associated With Key Measurement Variables
Measurement
Variable
Instrument and Sampling Errors (%)
Net Error (includes instrument, sampling,
and process variability)
Goal
Actual
Performance
Range
Error (%)
Control Rod
(Idle)
2% of full scale
(0.06 scfm)
1.34% of
calibration range
(0.04 scfm)
0.523 + 0.080 scfm
15
Test Rod (Idle)
2% of full scale
(0.002 scfm)
2.95 % of
calibration range
(0.0026 scfm)
0.019 + 0.002 scfm
13
Unit Valve
10% of full
scale (0.40
scfm)
-0.78 % of
calibration range
(0.047 scfm)
4.48 + 0.91 scfm
20
Gas
Chromatograph
NA
0.12 % of reading
97.28 + 0.12%
0.12
Table 4-5. Error Propagation and Overall Measurement Uncertainty
Verification Parameter
Uncertainty Due to Instruments and
Sampling
Net Uncertainty (includes instrument,
sampling, and process variability)
Performance Range
Error
(%)
Performance Range
Error
(%)
Natural Gas Emission Reductions
96 +0.05 % reduction
0.05
95.8 j^0.90 % reduction
0.94
Methane Emission Reductions
96 +0.05 % reduction
0.05
95.8 j^0.90 % reduction
0.94
Annual Gas Savings - Case 1
204,000+28,529 scfa
1.39
81,642+ 13,029 scfa
16
Annual Gas Savings - Case 2
617,213+2,407 scfa
0.39
617,375 +74,417 scfa
12
Payback period - Case 1 b
2.42 +.0.08 years
3.30
2.26 j^0.42 years
18
3 Based on gas savings measured on Engine 801 during the verification test period.
b Based on the Case 1 payback scenario of an average rod leak rate of 1.9 scfm and an average engine standby
rate of 55 percent where the payback period was 2.26 years.
4-10
-------
As shown in the table, the overall sampling and instrumental errors for all of the parameters were
very low and well within the 10 percent goal. Incorporation of process variability was not
included in the Data Quality Objectives, but was conducted to achieve a better understanding of
measurement uncertainty. Once process variability is factored into the uncertainty analyses, the
payback period errors exceed the objective.
Documentation of the uncertainty in the Case 1 payback period determinations was further
complicated because, as reported in Section 3.5, Case 1 payback was unobtainable on the test
engines due to the extremely low leak rates measured on the Control Rods. Therefore, the error
in payback was calculated based on the hypothetical typical industry case where rod emissions
average 1.9 scfm per rod, the engines are configured with three compressors, and engine standby
averages 55 percent (Table 3-8). The 16 percent uncertainty in the current Engine 801 Case 1 gas
savings measurements was applied to this hypothetical case to calculate the payback uncertainty.
The data quality of results corresponding to the 1.9 scfm industry average leak rate is not certain
because directly measured data were not available at the higher leak rates. The trends observed in
Static-Pac performance as a function of rod leak rate suggest that the extrapolation performed
based on measured data is legitimate. Nevertheless, the user is cautioned with potential
limitations for higher leak rate rods.
In summary, all of the data quality objectives were met with regards to the instrumentation and
sampling procedures used throughout the verification. Variability in the processes tested could
not be predicted prior to conducting the testing and therefore were not included in the data quality
objectives. The variability was determined through posttest data analyses and presented to
provide overall verification uncertainty.
4-11
-------
5.0 REFERENCES
GRI 1997. Documentation of Existing Rod Packing Technology and Emissions. GRI-97/0393,
Gas Research Institute, Chicago, IL, December 1997.
Harrison, Matthew R., Lisa M. Campbell, Theresa M. Shires, and R. Michael Cowgill 1996.
Methane Emissions from the Natural Gas Industry, Volume 2: Technical Report, EPA-600/R-96-
080b, (NTIS PB97-142939), U.S. Environmental Protection Agency, National Risk Management
Research Laboratory, Research Triangle Park, NC, June 1996.
Hummel, Kirk E., Lisa M. Campbell, and Matthew R. Harrison 1996. Methane Emissions from
the Natural Gas Industry, Volume 8: Equipment Leaks, EPA-600/R-96-080h, (NTIS PB97-
142996), U.S. Environmental Protection Agency, National Risk Management Research
Laboratory, Research Triangle Park, NC, June 1996.
Shires, Theresa M. and Matthew R. Harrison 1996. Methane Emissions from the Natural Gas
Industry, Volume 7: Blow and Purge Activities. EPA-600/R-96-080g, (NTIS PB97-142988),
U.S. Environmental Protection Agency, National Risk Management Research Laboratory,
Research Triangle Park, NC, June 1996.
SRI 1999. Testing and Quality Assurance Plan for the C. Lee Cook Division, Dover Corporation
Static-Pac™ System, SRI/USEPA-GHG-QAP-04, Greenhouse Gas Technology Verification
Center, Southern Research Institute, Research Triangle Park, NC, July 1999.
5-1
-------
APPENDIX A
Example Payback Calculations For Case 1
A-l
-------
Appendix A. Example Payback Calculations For
Case 1 (2 compressors per engine, 55% idle time)
Total Capital Cost (Year 0)
$4,808
from Table 3-9
Discount Rate (r)
10
%
Annual O&M Costs
$0
Annual Natural Gas Emissions Reduced
290,000
std. ft3/yr, from Table 3-8
Gas Cost
2.00
$/1000 std. ft3
Annual Gas Savings
$580
Net
Annual
Annual Gas
Net Annual
Discount Annualized
Present
Year O&M Costs
Savings
Savings
Factor
Savings
Value
t
1/(1+r)At
1
$0
$580
$580
0.91
$527
$4,281
2
$0
$580
$580
0.83
$479
$3,801
3
$0
$580
$580
0.75
$436
$3,366
4
$0
$580
$580
0.68
$396
$2,969
5
$0
$580
$580
0.62
$360
$2,609
6
$0
$580
$580
0.56
$327
$2,282
7
$0
$580
$580
0.51
$298
$1,984
8
$0
$580
$580
0.47
$271
$1,714
9
$0
$580
$580
0.42
$246
$1,468
10
$0
$580
$580
0.39
$224
$1,244
11
$0
$580
$580
0.35
$203
$1,041
12
$0
$580
$580
0.32
$185
$856
13
$0
$580
$580
0.29
$168
$688
14
$0
$580
$580
0.26
$153
$535
15
$0
$580
$580
0.24
$139
$396
16
$0
$580
$580
0.22
$126
$270
17
$0
$580
$580
0.20
$115
$155
18
$0
$580
$580
0.18
$104
$51
19
$0
$580
$580
0.16
$95
-$44
20
$0
$580
$580
0.15
$86
-$130
<—payback (between
years 18 and 19)
Using Microsoft Excel, "NPER" function:
Payback:
18.5
A-2
-------
APPENDIX B
Engine Operating Schedule for Phases I and II
B-l
-------
Engine Operating Schedule for Phase 1 and II
Date
Engine 801 Operational Data
(Hrs)
Engine 802 Operational Data (Hrs)
Shut-
downs
Running
Out of
Service
Idle
Shut-
downs
Running
Out of
Service
Idle
15-Jul
Testing
Testing
16-Jul
Testing
Testing
17-Jul
24
0
0
0
0
24
18-Jul
24
0
0
1
0
0
24
19-Jul
1
15.2
0.1
8.7
0
0
24
20-Jul
13.8
2.8
7.4
14
0.1
9.9
21 -Jul
24
0
0
24
0
0
22-Jul
24
0
0
24
0
0
23-Jul
24
0
0
24
0
0
24-Jul
24
0
0
24
0
0
25-Jul
24
0
0
24
0
0
26-Jul
24
0
0
24
0
0
27-Jul
1
13.9
0
10.1
24
0
0
28-Jul
9.7
6.4
7.9
24
0
0
29-Jul
23.7
0.3
0
24
0
0
30-Jul
24
0
0
24
0
0
31 -Jul
24
0
0
24
0
0
1-Aug
24
0
0
24
0
0
2-Aug
24
0
0
24
0
0
3-Aug
24
0
0
24
0
0
4-Aug
Testing
Testing
5-Aug
Testing
Testing
6-Aug
Testing
Testing
7-Aug
1
13.6
0
10.4
10.2
0
13.8
8-Aug
24
0
0
0
0
24
9-Aug
24
0
0
0
0
0
10-Aug
1
20.8
0
3.2
11.1
0
12.9
11-Aug
24
0
0
1
7.9
0
16.1
12-Aug
24
0
0
15
0
9
13-Aug
24
0
0
24
0
0
14-Aug
24
0
0
24
0
0
15-Aug
24
0
0
24
0
0
16-Aug
1
19.2
0
4.8
24
0
0
17-Aug
0
0
24
24
0
0
18-Aug
0
0
24
24
0
0
19-Aug
9.6
0
14.4
24
0
0
20-Aug
1
10
0
14
24
0
0
21-Aug
24
0
0
24
0
0
22-Aug
1
9.3
14.7
0
1
10.3
13.7
0
23-Aug
0
24
0
0
24
0
24-Aug
16.2
0
7.8
1
16.5
0
7.5
25-Aug
24
0
0
23.5
0
0.5
26-Aug
24
0
0
24
0
0
27-Aug
1
7.9
0
16.1
24
0
0
28-Aug
0
0
24
24
0
0
29-Aug
0
0
24
24
0
0
30-Aug
0
0
24
24
0
0
31-Aug
0
0
24
24
0
0
(continued)
B-2
-------
Engine Operating Schedule for Phase 1 and II (continued)
Date
Engine 801 Operational Data
(Hrs)
Engine 802 Operational Data (Hrs)
Shut-
downs
Running
Out of
Service
Idle
Shut-
downs
Running
Out of
Service
Idle
1-Sep
10.1
0
13.9
24
0
0
2-Sep
1
11.3
0
12.7
24
0
0
3-Sep
0
0
24
24
0
0
4-Sep
0
0
24
24
0
0
5-Sep
0
0
24
24
0
0
6-Sep
0
0
24
24
0
0
7-Sep
0
0
24
24
0
0
8-Sep
0
0
24
24
0
0
9-Sep
0
0
24
24
0
0
10-Sep
12.7
0
11.3
24
0
0
11-Sep
24
0
0
24
0
0
12-Sep
24
0
0
24
0
0
13-Sep
24
0
0
24
0
0
14-Sep
24
0
0
24
0
0
15-Sep
24
0
0
1
23.7
0
0.3
16-Sep
24
0
0
24
0
0
17-Sep
24
0
0
24
0
0
18-Sep
24
0
0
24
0
0
19-Sep
24
0
0
24
0
0
20-Sep
24
0
0
24
0
0
21-Sep
Testing
Testing
22-Sep
Testing
Testing
23-Sep
Testing
Testing
24-Sep
24
0
0
1
9.1
0
14.9
25-Sep
24
0
0
0
0
24
26-Sep
24
0
0
0
0
24
27-Sep
24
0
0
12.3
0
11.7
28-Sep
24
0
0
24
0
0
29-Sep
24
0
0
24
0
0
30-Sep
1
11.8
0
12.2
1
23.1
0
0.9
1-Oct
0
24
0
0
24
0
2-Oct
0
24
0
0
24
0
3-Oct
24
0
0
24
0
0
4-Oct
1
9.7
0
14.3
1
18.3
0
5.7
5-Oct
0
0
24
0
0
24
6-Oct
16.1
0
7.9
16.3
0
7.7
7-Oct
24
0
0
24
0
0
8-Oct
24
0
0
24
0
0
9-Oct
1
22.6
0
1.4
1
22.3
0
1.7
10-Oct
1
9.8
0
14.2
12.3
0
11.7
11-Oct
11.3
0
12.7
24
0
0
12-Oct
24
0
0
24
0
0
13-Oct
24
0
0
24
0
0
14-Oct
1
16.4
0
7.6
24
0
0
15-Oct
16.4
0
7.6
24
0
0
16-Oct
24
0
0
24
0
0
17-Oct
24
0
0
24
0
0
18-Oct
24
0
0
24
0
0
19-Oct
24
0
0
24
0
0
20-Oct
24
0
0
24
0
0
(continued)
B-3
-------
Engine Operating Schedule for Phase 1 and II (continued)
Date
Engine 801 Operational Data
(Hrs)
Engine 802 Operational Data (Hrs)
Shut-
downs
Running
Out of
Service
Idle
Shut-
downs
Running
Out of
Service
Idle
21-Oct
24
0
0
24
0
0
22-Oct
24
0
0
24
0
0
23-Oct
24
0
0
24
0
0
24-Oct
24
0
0
24
0
0
25-Oct
24
0
0
24
0
0
26-Oct
24
0
0
24
0
0
27-Oct
24
0
0
1
11.6
0
12.4
28-Oct
24
0
0
5.4
0
18.6
29-Oct
24
0
0
24
0
0
30-Oct
24
0
0
1
13.2
0
10.8
31-Oct
1
22.3
0
1.7
11
0
13
1-Nov
12.3
0
11.7
24
0
0
2-Nov
1
20.1
0
3.9
24
0
0
3-Nov
24
0
0
24
0
0
4-Nov
24
0
0
24
0
0
5-Nov
1
15.7
0
8.3
1
15.7
0
8.3
6-Nov
0
0
24
0
0
24
7-Nov
0
0
24
0
0
24
8-Nov
14
0
10
13.5
0
10.5
9-Nov
24
0
0
24
0
0
10-Nov
24
0
0
24
0
0
11-Nov
1
9.2
0
14.8
1
8.4
0
15.6
12-Nov
0
0
24
8.5
0
15.5
13-Nov
0
0
24
1
10.7
0
13.3
14-Nov
8.3
0
15.7
0
0
24
15-Nov
24
0
0
10.8
0
13.2
16-Nov
24
0
0
24
0
0
17-Nov
1
23.1
0
0.9
1
18.5
0
5.5
18-Nov
24
0
0
24
0
0
19-Nov
24
0
0
24
0
0
20-Nov
1
17.9
0
6.1
24
0
0
21-Nov
0
0
24
1
20.1
0
3.9
22-Nov
13.1
0
10.9
13.2
0
10.8
23-Nov
24
0
0
24
0
0
24-Nov
1
14.5
0
9.5
24
0
0
25-Nov
0
0
24
24
0
0
26-Nov
0
0
24
1
23.6
0
0.4
27-Nov
0
0
24
0
0
24
28-Nov
12.5
0
11.5
14.8
0
9.2
29-Nov
24
0
0
24
0
0
30-Nov
24
0
0
24
0
0
1-Dec
24
0
0
24
0
0
2-Dec
1
4.6
0
19.4
24
0
0
3-Dec
10.3
0
13.7
24
0
0
4-Dec
24
0
0
24
0
0
5-Dec
24
0
0
24
0
0
(continued)
B-4
-------
Engine Operating Schedule for Phase 1 and II (continued)
Date
Engine 801 Operational Data
(Hrs)
Engine 802 Operational Data (Hrs)
Shut-
downs
Running
Out of
Service
Idle
Shut-
downs
Running
Out of
Service
Idle
6-Dec
1
0.6
0
23.4
24
0
0
7-Dec
Testing
Testing
8-Dec
Testing
Testing
9-Dec
Testing
Testing
10-Dec
23.9
0
0.1
24
0
0
11-Dec
24
0
0
24
0
0
12-Dec
24
0
0
24
0
0
13-Dec
24
0
0
24
0
0
14-Dec
24
0
0
24
0
0
15-Dec
24
0
0
24
0
0
16-Dec
24
0
0
24
0
0
17-Dec
24
0
0
24
0
0
18-Dec
24
0
0
24
0
0
19-Dec
24
0
0
1
12.6
0
11.4
20-Dec
1
20.3
0
3.7
0
0
24
21-Dec
0
0
24
0
0
24
22-Dec
22.4
0
1.6
1
22.1
0
1.9
23-Dec
24
0
0
0
0
24
24-Dec
24
0
0
0
0
24
25-Dec
24
0
0
0
0
24
26-Dec
24
0
0
0
0
24
27-Dec
24
0
0
0
0
24
28-Dec
24
0
0
0
0
24
29-Dec
24
0
0
0
0
24
30-Dec
24
0
0
0
0
24
31-Dec
24
0
0
0
0
24
1-Jan
1
23.3
0
0.7
0.3
0
23.7
2-Jan
2.8
0
21.2
1
22.6
0
1.4
3-Jan
24
0
0
24
0
0
4-Jan
24
0
0
24
0
0
5-Jan
1
22.8
0
1.2
24
0
0
6-Jan
0
0
24
24
0
0
7-Jan
0
0
24
24
0
0
8-Jan
0
0
24
24
0
0
9-Jan
0
0
24
24
0
0
10-Jan
15.1
0
8.9
1
8.9
0
15.1
11-Jan
24
0
0
15.9
0
8.1
12-Jan
1
17
0
7
24
0
0
13-Jan
0
0
24
24
0
0
14-Jan
0
0
24
24
0
0
15-Jan
0
0
24
24
0
0
(continued)
B-5
-------
Engine Operating Schedule for Phase 1 and II (continued)
Date
Engine 801 Operational Data
(Hrs)
Engine 802 Operational Data (Hrs)
Shut-
downs
Running
Out of
Service
Idle
Shut-
downs
Running
Out of
Service
Idle
16-Jan
0
0
24
24
0
0
17-Jan
0
0
24
24
0
0
18-Jan
0
0
24
24
0
0
19-Jan
0
0
24
1
14
0
10
20-Jan
0
0
24
0
0
24
21-Jan
0
0
24
0
0
24
22-Jan
0
0
24
0
0
24
23-Jan
0
0
24
0
0
24
24-Jan
11.6
0
12.4
15
0
9
25-Jan
Testing
Testing
26-Jan
Testing
Testing
27-Jan
Testing
Testing
Totals
27
2944.8
96.3
1350.9
22
3292.3
85.8
989.9
B-6
-------
APPENDIX C
Static-Pac™ Operator's Manual
Automatic Control System
C-l
-------
STATIC-PAC - Cer.pnsasr Rod Packing Shuo-tfcwn Sealing Sy»toa Paga '¦
*urou?:c Conrad system - craving ^-3328-3
IKSTiLUTION AJaC GLJE RATIO"
A. 1VS TALL&TION
T>,e $i.jt,ic-?as Automatic Csntrol is resigned to 'ae used wish s ?r.e
6r.gi.ne asntrc-I ay aim wiiefc includes a pr.#y»atioaliy cpt!*»ted crwleini air
valve, pneusRcio ignition switch, ar.d/sr 3 pnttinaiically sperated f'j«l gas
valve.
The Svj: Ic-Pbc eonirsl will automatically engage und disengage the sera pressor
packing Static-Pasis) «ith ccn-inei fror. -,r.« engir.s scr.tr ci system vrien
prcpwly iastsiltd.
tr.e starting air cost, and signal froa the engine eor.tral s*«'«s is ts be
diJ3onneCv« frca t'r.a pilot of fna starring sir valve and e«r,r!«jUd to
bvligieaa no, .5 of the Statin-Pac sont-rcl. 7;ie pilot of tins starting air v«lv»
insula b*> iTr.iac^ea to &ulkr.Raa r,a. t of the Static-Pac cor.trcl. Install a
tee fitting in fr.e ignition cs-msng lins fr«r, w»e s-ngine sor.trsl farsl and
connect the branch of tr.e tee to "Bulkhead r.a. 3 of the Sia-ic-?aa control (If
an Ignitisn-ON ccircar.c si jr.si is r-Crt avaiistla, tr.c fu»l~ON signal cart Us^ ua«d
initea-a), Cor.r.sst huIWneas -a. 2 to pficr. (operator! sf high pressure valve
"CO-*,; corniest r.igr. pressure gas supply to b! iz/.ei inlet part of valve 15S— <,.
ec-fteat Stati=-?ic(sJ to oppsslte pcrr., s;p6 third port (vent) to s «fe,
•.nrsstfriatcri vena sysisni to atr.osphers, Connect frglyfteyi ho. '* to i'<31-3 a tor
I ??-' , after insteicor nas b-een positioned ir. cicsirec l«c»Sios. C&nnee* 65 to
*15 ssig filtered z-jpply air to fc'.fi'cteac «•. 6, Installation is ee«;ste.
s, gfESATIOg
EriSir.s/acraprssssr is stepped. Supply air ar.d engine panel Skirting Air arid
Isnitior. ( zr f'jelj :o~»r3 signals art senneored to Static-Pao corfcrci. Hi jr.
pressure 30S is eonresceii to t'ne Lnl01 sf central valvt 13C-1 *riio" Is pipad
to Stntic-fsoi s) ana ws vent,
Sjjply air enters through b-jl^ead ns. -5 t» tha inlet sf valve,,.?-'.- If 3~"> i#
Kiit* mmually latched alcstd, air pass?® thrcjgh 9-1 to b-j'khfw: no. 2 a-.e.
h'Jlt&ee* nc. «!~ pressure frost c-jlkheas no. Z wst«ges allot (operator) sf
7Hv« -i-O-'. sr.ifii5 vulva so that hign pres'stire ?ss passsa '^rgegh valve to
St»t,ic-?«oU} on cgsr.pressor, causing the* v> engage, frm«r« frsa baljettad
no, ^ is ro'jtid ta ts ir.dlsatsr '9R-' , shifting it to tha red pesiticr, to stow
that i-ne St8tie-?ao; a) art ^r;a?ec .
Cerroratisn/I. ~'®e Caok Hlvisicn LsuisvllLs, K#r,ty«Ky Jufie 3, 9s3
C-2
-------
5TAII2-FAC - Compress.";" S.nc Packing S'rtJi~.icwn Stalin; Systsrt P=gg
AIJTMAr:c :CfJI3X s^sra - Di-swing u'-nzz-i
'4b,e.r. ;he engine ;cntrcl syi-.er: sends the at.irtisg air cos a and aisnal to
Sul^ntaa -10, H, sir will flaw to shuttle vaiv» ' = ^'- ,jr;S or thrs-jgh flow
sontrci valve "\-2 in th» »"re stritt.ee direction w i«-eri iataly fill vol '.mo
shsnogr 2Q-2, ars'ifsiRg valve . Vulva g-1 vftun xtified vtr.ts fccikheaes ?. i,
aUcvi-g valve 100-1 to vent the .S&atia-FatKs) ann indisatcr whter.
retj-n& ts tns Disc/ poaittsr,, Trie Static-PacCs"? are nsw disengiftsa,
Sir.yltar.Huysly, a I? is flowing flew cc.-.trol -/nlve In ~r.e
"Ictftc dir^c.-inn tc a.Ow.y fill vol'^.t chamber 20-' wrich Is conr.sct^c to
the pile; of valve d"l. Valv» is aejustsd "for a 15 seaonc selay after
v.'iisf, valvg 5-'i shifts to the open position, ellcwirj pressure fcn ilov thresh
i'-jiXiaac no. 1 ts the pilot of starting air valve, cranking the engxri*. Tna
bis; a 3Hay insures that trie Statie-F,ic{ s) are dlser.jaged befgre trie ergir„a
rails. At the proper tine, t'ns engine csortroi panel will send a Icriuion-OS
Inr fjel-OS) sign?.! to Ststie-Pao control ^>i.l.tf-.«*o no, 3, 7nis signal -vi.'l
ra-,g:n „t;iie englr:» is rursniRg «nd ttxougts sfeu&i* valve '§-•• -«tll keep ai^nsl
to jl-.t.Q't valve '>0-1 vented, kscpir.g Static-Pasva) os era-renscr oisengnged.
Siarti.-j^ air signal sfc &ul ten art no. 5 will 5e ver.tea after sifir.e r.as attained
firing speed and valve I-;, will return ts fcha norm.il";;,• closed position,
tiie pilot a;" tf-.e istsrtin? sir valve, stopping all crenkir.g., Cn*sk
vel-/s ^Q-1 iTisyrss t»>t pilot air is ventee frsn t^e star tin?, sir valve
i-."9C-«-.e-y ,ie ths I535 of tne starting sir ac-nard signal, tr,« »r.gi~e Is new
running wit ft iha Ststio-rscl •! on the compressor c:se'P.j:»i .
rt'Ssn -ne engine control sy'stae signp; 5 a shut dowr. by venting pressure fror,
bulV* *?ac! .no, 3, tht sir trapped in ydim* sr.amfcgr g"-.1: will be slowly veasasi
tn..-3'jgr. flow octroi valvij i;-a m the rastrtctea dirceticn and an tr,r-;-jgh
stt'jv.ia vglva 15-!_ to kneafl nu 3. Vslve '3-3 is ? vS flow
tr.rougn frs.ti b>j._Khiaad no. S ts tylkh^ada ns cauair.g valvg *QQ~" re
acpiv pressure ts tha Sistio-Pi-sla) and "5" i;v51cst*3r 19H-1 r»:.i:rii;r.? 13 to
the red ,r»sitior, "STATIC-? AC Is) E.'iC-Al-E;" .
The S;acis-?aa .-sr.trol ntn Sa operates nsninnlly tt aisengsge t.ts ccnprcss&r
Ststi£~?ae(s) fr>r Eair.tsr-anci v
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