Evtf
Greenhouse Gas Technology Verification Center
A USEPA Sponsored Environmental Technology Verification Organization
Testing and Quality Assurance QA Plan for the
France Compressor Products
Emissions Packing
Prepared By:
Southern Research Institute
Greenhouse Gas Technology Verification Center
Research Triangle Park, NC USA
Telephone: 919/403-0282
For Review By:
France Compressor Products 1^1
ANR Pipeline Company 1^1
The Oil and Gas Industry Stakeholder Group 1^1
USEPA Quality Assurance Team ^
July 1999
1^1 indicates comments are integrated into Plan
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TABLE OF CONTENTS
Page
1.0 BACKGROUND AND INTRODUCTION 1
2.0 TECHNOLOGY DESCRIPTION AND VERIFICATION APPROACH 3
2.1. EMISSIONS PACKING SYSTEM DESCRIPTION 3
2.2. VERIFICATION PARAMETERS AND THEIR DETERMINATION 5
2.2.1. Approach 5
2.2.2. Phase I Emissions Packing Evaluation 10
2.2.3. Phase II Emissions Packing Evaluation 13
2.2.4. Generalization of Results 16
2.3. SITE SELECTION, DESCRIPTION, AND EMISSIONS PACKING
INSTALLATION 17
2.3.1. Site Selection and Description 17
2.3.2. Emissions Packing Installation and Operation 18
2.4. FIELD TEST OVERVIEW 18
2.4.1. Rod Packing Leak Rate Measurements 18
2.4.2. Component Leak Rate Measurements 19
2.5. SCHEDULE 01 ACTIVITIES 22
3.0 DATA QUALITY OBJECTIVES 22
3.1. ROD LEAK MEASUREMENTS 23
3.2. COMPONENT LEAK RATE MEASUREMENTS 23
3.3. PROJECTIONS 24
4.0 DATA QUALITY INDICATORS 25
5.0 SAMPLING/ANALYTICAL AND QA/QC PROCEDURES 25
5.1. ROD LEAK MEASUREMENTS 25
5.2. COMPONENT LEAK RATE MEASUREMENTS 26
5.2.1. Blow-down Valve, and Pressure Relief Valve 27
5.2.2. Miscellaneous Components 28
5.2.3. Unit Valves 28
5.3. DATA ACQUISITION 29
6.0 DATA REDUCTION, VALIDATION, AND REPORTING 31
6.1. DATA REDUCTION 31
6.1.1. Rod Leak Measurements 31
6.1.2. Component Measurements 32
6.1.3. Gas Savings and Payback period 32
6.1.4. Unit Conversions 32
6.2. DATA REVIEW AND VALIDATION 32
6.3. DATA ANALYSIS AND REPORTING 34
7.0 AUDITS 35
8.0 CORRECTIVE ACTION 35
9.0 PROJECT ORGANIZATION 36
TABLE OF CONTENTS
(continued)
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Page
10.0 TEST PROGRAM HEALTH AND SAFETY 37
11.0 REFERENCES 38
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1.0 BACKGROUND AND INTRODUCTION
The Environmental Technology Verification (ETV) program was established by the United States
Environmental Protection Agency (EPA) in response to the belief that there are many viable
environmental technologies which are not being used for the lack of credible third-party
performance testing. With the performance data developed under the program, technology buyers
and permitters in the United States and abroad will be better equipped to make informed
environmental technology purchase decisions. In late 1997, EPA selected the Southern Research
Institute to manage one of twelve ETV verification entities: The Greenhouse Gas Technology
Verification Center (the Center). Eleven other ETV entities are currently operating throughout the
United States conducting third-party verification in a wide range of environmental media and
industries.
In March of 1997, the Center met with members of the Executive Stakeholder Group. In that
meeting, it was decided that the oil and gas industries were good candidates for third-party
verification of methane mitigation and monitoring technologies. As a consequence, in June 1998,
the Center hosted a meeting in Houston, Texas with operators and vendors in the oil and natural
gas industries. The objectives of the meeting were to: (1) gauge the need for verification testing in
these industries, (2) identify specific technology testing priorities, (3) identify broadly acceptable
verification and testing strategies, and (4) recruit industry stakeholders. Industry participants
voiced support for the Center's mission, identified a need for independent third-party verification,
and prioritized specific technologies and verification strategies. Since the Houston meeting, a 19
member Oil and Gas Industry Stakeholder Group was formed, vendors of GHG mitigation devices
were solicited in several top-rated technology areas, and verification testing of several compressor
leak mitigation and other devices has begun.
France Compressor Products (Coltec Industries, Inc.) has committed to participate in a long-term
independent verification of their static sealing technology. The France Emissions Packing is
designed to reduce methane leaking from compressor rod seals during periods of compressor
shutdown without full depressurization. There are over 13,000 natural gas compressors operating
in the United States alone, a significant number of them experiencing frequent shutdowns. When
the compressor remains pressurized during these periods, rod leaks continue at rates similar to or
higher than those that occur during normal operation. According to the Gas Research
Institute/Environmental Protection Agency study "Methane Emissions from the Natural Gas
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Industry ("GRI Study"), compressor rod seal leaks during periods of shutdown represent a major
source of methane emissions, and a significant loss of economic and natural resources.
A test of the Emissions Packing will be carried out at a compressor station operated by ANR
Pipeline Company (ANR) of Detroit, Michigan. This Test Plan describes the technology to be
tested, and outlines the Center's plans to conduct the verification in a field setting.
Field testing of the Emissions Packing is scheduled to begin at the ANR site in July 1999, and will
continue for up to 4 months. After initial installation and testing is complete, the Center will issue
a Phase I Report, containing installation and initial verification measurements data (October 1999).
After all testing is complete, a Phase II Report will be issued which contains longer-term technical
and economic performance verification data (2 months after-completion of the field evaluation).
The specific verification parameters associated with the Phase I and Phase II efforts are listed
below. Determination of each parameter is discussed in Section 2.2.
Phase I Emissions Packing Evaluation:
Document initial gas savings for primary baseline operating conditions (Case 1
and Case 2 see Section 2.2)
Document capital, installation, and shakedown requirements and costs
Phase II Emissions Packing Evaluation:
Document annualized gas savings for primary baseline conditions
Document methane emission reduction
Calculate and document Emissions Packing payback period
Phase I goals will be achieved through observation, collection and analysis of direct gas
measurements, and use of site operator logs and vendor supplied cost information.
A primary goal of Phase II is determination of the Emissions Packing payback period. As a
practical matter, the Center cannot conduct direct testing for the several years that would be
required to determine payback. Thus, several Phase II goals will be accomplished through a
combination of medium-term measurements (several months), data extrapolation, and collecting
and presenting data adequate to calculate payback for various operating/shutdown scenarios.
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Extrapolation and other assumptions will be transparent in the final report, allowing readers to
make alternate assumptions and assessments as needed.
2.0 TECHNOLOGY DESCRIPTION AND VERIFICATION APPROACH
2.1. EMISSIONS PACKING SYSTEM DESCRIPTION
The France Emissions Packing is a modification of a conventional rod packing which has the result
of reducing or eliminating emissions during idle periods. It is a simple design. A spring-loaded
plate is added to the final packing cups in a conventional rod packing case. This plate keeps the
sealing surfaces of the conventional sealing rings in contact during idle periods - reducing or
eliminating leaks.
The emissions packing for the ANR test site is a common type and contains 8 cups (see Figure 1).
The first cup or groove is occupied by the breaker ring (Figure la) whose function is to reduce the
pressure on the packing rings by providing an orifice restriction to flow. A second function 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.
LAPPED
DRILL 1.125 DU 1
OH * 9.000 B.B.C.
8 PLACES
GASKET
584-0037-03702-110
PLAIN PLATE
186-0400-07330
revision
I84-0400-07329-
GASKET CUP
&CKED
114-0400-98381-112
DESCRIPTION
Figure 1. France Emissions Packing
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PRESSURE-*
Cup #1
Breaker Ring
Cups #2-6
| Cup #7
61!
a
2
u
«
0-
£
Spring
Plate
Cup #8
Spring
Plate
Conventional
Ring Sets
Figure la. France Emissions Packing - Ring Detail
Cups 2 through 6 are occupied by conventional three-ring packing sets consisting of a radial cut, a
tangent cut ring, and a backup ring (see Figure la). A more detailed description of this and other
common sealing arrangements is given in GRI's report documenting existing compressor rod
packing technology and emissions (GRI 1997). During the discharge stroke, pressure is exerted on
the seals which (1) forces the mating faces together and (2) constricts the tangent cut seal against
the rod. During the intake stroke, the pressure is rapidly reduced in the cylinder and gas flows
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from around the sealing rings back toward the cylinder. During this cycle, the rings are free to
move back and forth within the cups (more or less so depending on how much differential pressure
they experience and the movement of the rod). Most rings seal only on the compression faces, but
some rings seal on both faces. The tangent cut ring is pressed against the rod once each cycle at the
start of the compression stroke, and can move away during the intake stroke. During idle periods
(with the unit remaining pressurized at station suction pressure), the pressure equalizes around the
rings and they can float within the cups - potentially compromising the seal.
With the France emissions packing, a spring-loaded pressure plate is added to the ring assemblies
in the final cups (7 and 8). This plate keeps pressure on the sealing faces of the rings, maintaining
the seal when the unit is idle. France currently has over 30 installations where pressure plates have
been added to the final cups to effect static sealing. Sealing performance is claimed to be very
good. In these cases, to fit the pressure plates into a conventional packing case, the backup ring
was removed. In a few instances, there has been some extrusion of the ring material due to the
absence of the backup plate. For the ANR test, the packing case was modified to allow room for
both the pressure plate and the backing ring. This modified system should provide static sealing
and prevent extrusion. The modification was accomplished by removing the final three sealing
cups and replacing them with a France "T-cup" which contains the pressure plate and the ring
assembly. The Emissions Packing contains one less ring set than the packing being replaced in
order to allow room for the addition of the pressure plates. France does not expect this
modification to influence running or idle emissions; however, both of these will factors be
quantified as part of the test.
2.2. VERIFICATION PARAMETERS AND THEIR DETERMINATION
2.2.1. Approach
The Emissions Packing is designed to provide sealing during shutdown periods. Therefore, the gas
savings depend on the number and duration of shutdown periods. In addition, changes in operating
procedures associated with installation of the static seal must be considered in determining net gas
savings.
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Normal compressor shutdown procedures vary from station to station. In general, the following
procedures are used:
Depressurize/blow-down all pressure (except a small residual pressure to
prevent air in leakage) and vent the gas, either partially or completely, to the
atmosphere,
Maintain pressure, either with or without the unit isolation valves open,
Depressurize to a lower pressure, either venting the gas to the atmosphere or to
the station fuel system, or
A combination of these procedures.
Adding an Emissions Packing to a compressor will result in varying levels of net gas savings and
emission reductions depending on the current shutdown procedure. Evaluation of net emission
reductions for Emissions Packing operation requires quantifying any significant leak rate changes
resulting from normal Emissions Packing operation and related changes in operating procedures.
A station that currently leaves compressors pressurized during shutdown will realize net savings
simply from the decrease in the rod packing leak rate due to the action of the static seal. If a station
that currently blows down its compressors during shutdown were to add static seals, it is presumed
that the station would change to a pressurized shutdown condition. In this case, the savings result
from the eliminated blow-down and the unit valve leak (the unit valves are prevented from leaking
because the unit now remains pressurized). There is also the potential for increases in emissions at
components now exposed to pressure during shutdown.
Table 1 shows the relationship between operating procedures and emission changes at other leak
sources in the compressor system for common shutdown scenarios.
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Table 1. Common Shutdown Scenarios and Emissions Changes with Static Seals
ch4 source
CASE #1
CASE #2
CASE #3
CASE #4
CASE #5
Current
shutdown
procedure
Pressurized
shutdown with
unit valves open
Blow-down/
100% vent to
atmosphere
Pressurized
shutdown with
unit valves
closed
Depressurize to a
lower pressure
a. Vent to
atmosphere
b. Vent to fuel
system
Depressurize/ vent
to fuel system,
then vent to the
atmosphere
Procedure with
static seal
n/c
Pressurized
shutdown
n/c
Pressurized
shutdown
Pressurized
shutdown
Emissions Changes with Static Seal
Rod seals
decrease
small increase?
decrease
small increase?
small increase?
Blow-down
volume
n/c
decrease
n/c
a. decrease
b. decrease
Decrease
Unit valves
n/c
decrease
n/c
a. decrease
b. n/c
decrease
Blow-down
valve (fugitive
leaks)
n/c
increase
n/c
a. increase
b. increase
increase
Pressure relief
valve (fugitive
leaks)
n/c
increase
n/c
a. increase
b. increase
increase
Misc. valves,
fittings, flanges,
etc. (fugitive
leaks)
n/c
increase
n/c
a. increase
b. increase
increase
NOTES: n/c - no change/effectively no change
The evaluation of the Emissions Packing performance at ANR Pipeline Company will focus on two
shutdown scenarios, (1) pressurized when idle (Case 1) and (2) de-pressurized (blow-down) when
idle (Case 2). These two operating procedures represent the most common approaches to
compressor shutdown. Based on data contained in the GRI methane study (GRI 1996), about 57
percent of idle transmission compressors are maintained at operating pressure and 38 percent are
blown-down to atmospheric. A smaller percentage (less than 5 percent) are blown-down to a lower
pressure (in some cases venting to the fuel system). The following discussion highlights the
verification issues for each case and outlines measurements and data collection activities needed to
implement the verification test.
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Case 1: The baseline for this case is a compressor that normally maintains full operating pressure
during idle periods. The addition of the Emissions Packing should reduce or eliminate leaks that
occur during idle periods and cause little or no change in the leak rate while the compressor is
operating.
Emissions reductions will be determined by comparing uncontrolled emissions with emissions
controlled by the Emissions Packing. It is not possible to obtain a direct measurement of
uncontrolled emissions since the Emissions Packing cannot be disabled. Therefore, uncontrolled
emissions will be characterized based on measurements of emissions during idle periods from a
second rod (the control rod) on the same engine using a new conventional packing. This
arrangement will be repeated on two separate engines in order to provide a more reliable and robust
data set.
Leak rate measurements on the control rods during idle and operation periods will be used as a
baseline for verifying the emissions reductions during idle periods, and any change in running
emissions that may occur due to the Emissions Packing.
Because the unit pressure is essentially unchanged during both operating and idle periods, all other
component leak rates (pressure relief valve, blow-down valve, unit valves, and miscellaneous
flanges, valves, and fittings) can be anticipated to remain constant after installation of the
Emissions Packing. This will be verified by manual measurements before and after installation.
Case 2: The baseline for this condition is a compressor that normally blows down from operating
pressure to a minimum pressure level during idle periods. At such times, the pressure on
compressor components is reduced to near zero and any rod packing, pressure relief valve and
blow-down valve leaks cease. However, any leaking gas from the unit valves isolating the
compressor is lost. The gas leaks into the compressor system, and passes to the atmosphere
through the open blow-down valve to the open-ended blow-down line. Based on available data, the
loss from the unit valves can be substantial (see Table 2). To address this, unit valve leak rates will
be measured. This gas will be considered a savings associated with the use of the Emissions
Packing.
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In addition, the compressed gas contained in the compressor lines is lost during the blow-down.
This gas will also be considered a savings associated with the Emissions Packing. This will be
calculated based on known volumes of compressor components and operating pressure.
In order to determine net gas savings, any increase in leaks from the pressure relief valve, blow-
down valve, and various flanges, connectors, and valves due to leaving the unit pressurized must be
measured. The sum of any increase in leaks from these components offsets the gas savings
described above.
Components that require quantification of gas leak rate during the evaluation are identified in Table
2. The table also presents estimates of the leak rate for each component based on GRI studies (GRI
1996) and indicates gas savings or loss associated with each component for each test scenario.
Table 2. Leak Sources, Emissions, and Gas Savings
Emissions Sources
Notes
Gas Savings/Loss Associated with
Emissions Packing (Mcf/yr)
Gas Savings/Loss
High
Low
Avg.
Compressor Seal
Unit Idle, Pressurized
2,212
84
670
Case 1 Savings
Compressor Seal
Unit Operating
(0)
(0)
(0)
Case 1 Loss
2.212 X4 f.^0 * !IS£ 1 y (,!IS
Sa\ niiis
Blow-down Volume
Loss eliminated due to
change in operating
procedure associated
with static seal
2,750
220
825
Case 2 Savings
Unit Valves
Loss eliminated due to
change in operating
procedure associated
with static seal
2,916
67
1,491
Case 2 Savings
Blow-down Valve
Unit Idle, Pressurized
(587)
(235)
(436)
Case 2 Loss
Pressure Relief Valve
Unit Idle, Pressurized
(256)
(0)
(149)
Case 2 Loss
Misc. Components
Unit Idle, Pressurized
(75)
(52)
(64)
Case 2 Loss
Compressor Seal
Unit Idle, Pressurized
(0)
(0)
(0)
Case 2 Loss
Compressor Seal
Unit Operating
(0)
(0)
(0)
Case 2 Loss
4.74X 0 I.M.K ( i,S^ 2 C'ilS
Sa\ nigs
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2.2.2. Phase I Emissions Packing Evaluation
Document Initial Gas Savings for Baseline Operating Conditions (Case 1. Case 2)
Initial gas savings will be determined and reported in the Phase I Report based on three sets of
manual measurements conducted at roughly equal intervals (beginning, middle, and end) over a 4
week period of operation. Table 2 (above) lists the components for which emissions measurements
will be made. Net gas savings will be determined separately for Case 1 and Case 2 as discussed
above.
For Case 1, the savings consist solely of the gas prevented from leaking from the rod packing
during idle periods. This is the difference between the leak rate without the Emissions Packing
(measured on the control rods) and the leak rate (if any) with the Emissions Packing. In addition, if
it is determined that the Emissions Packing causes any increase in emissions during operation,
these emissions must be subtracted from the gas savings. The following formulas (Equations 1 and
la) state how gas savings will be calculated.
G1j = [Qu - Qs] * t (Eqn. 1)
Where,
G1 = Gas savings for each idle period (Case 1), cf
Qu = uncontrolled leak rate (control rod), scfm
Qs = leak rate during shutdown, scfm
t = shutdown period, minutes
The total gas savings for the test period is
G1 = S G1j - Vm (Eqn. 1a)
where Vm is the increase in operating emissions (if any) over the test period due to the Emissions
Packing. Vm is the difference between emissions for the test and control rods.
For the Phase I evaluation, cumulative gas savings during idle periods will be calculated and
reported as Case 1 gas savings. Details of the measurement methods, tests to be conducted,
QA/QC and schedule are given in Section 5.
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For Case 2, gas savings consists of the blow-down volume (times the number of idle periods) and
the unit valve leak rate (times the duration of idle periods). In addition, there are gas losses due to
leakage from the blow-down valve, pressure relief valves and miscellaneous components (see
Table 2). An additional loss is any gas that escapes past the Emissions Packing (since the baseline
for this case is a blown-down compressor, rod packing leakage would be zero). For Case 2, the gas
savings for each idle period will be calculated as follows.
G2j = BDV + Quv * t [Qprv Qbdv Qmisc Qs] * t (Ec|n. 2)
Where,
G2 = gas savings for each idle period (Case 2), cf
BDV = blow-down volume, cf
Quv = unit valve leak rate, cfm
Qprv = pressure relief valve leak rate, cfm
Qbdv = blow-down valve leak rate, cfm
Qmisc = aggregate leak rate for miscellaneous components, cfm
Qs = rod leak rate (cfm)
t =shutdown period, minutes
The total gas savings for the test period is
G2 = SG2j-Vm (Eqn. 1b)
where Vm is (once again) the total increase in operating emissions (if any) over the test period due
to the Emissions Packing.
Note that these calculations (for both Case 1 and Case 2) are for each idle period that occurs during
the test period. Since results will be based on periodic manual measurements, there will likely be
idle periods for which there are no direct measurements. To account for this, a trend line will be
developed for emissions results spanning the direct measurement periods, and values from this
trend line will be applied to corresponding idle periods to calculate gas savings. Information on
start/stop times for the test engines will be obtained from the ANR site data acquisition system.
The blow-down volume for the test unit has been calculated by ANR personnel to be 200 cf at 800
psi or roughly 55,000 scf. For the other components, manual leak rate measurements will be
needed. These measurements will be made during intensive measurement periods at the start,
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middle and end of the Phase I evaluation. Details of the measurement methods, tests to be
conducted, QA/QC and schedule are given in Section 5.
Document Capital. Installation, and Shakedown Requirements and Costs
The Emissions Packing will be installed by ANR site personnel, with supervision and guidance
provided by a France engineer. Center personnel will be on-site throughout the installation and
shakedown process, and will document any modifications made or difficulties encountered. The
Center will also document key decisions made regarding placement of equipment or adjustments
made for site-specific conditions.
France will provide written instructions as needed on start-up activities and routine monitoring and
maintenance requirements. The Center will document any problems encountered or changes made
to the start-up and shakedown activities, and report the final procedures in the Verification Report.
To determine the payback period, it will be necessary to document Emissions Packing capital and
installation costs. The cost for a new packing case for the ANR test compressor is $1,972.77 and
the packing ring set is $1,390.31, for a total cost of $3,363.80. A customer could modify their
existing packing cases, if they had spares, and effectively reduce the cost of buying a new case by
as much as 50 percent. Labor for installation is expected to be about 2 hours per rod (two
mechanics). This is a preliminary estimate. France may add or delete items necessary to
accommodate site specific conditions. ANR site personnel will provide information on labor and
other costs associated with the installation, operation and maintenance of the emissions packing.
The Center will obtain the "as-built" equipment list from France after installation is complete, and
will document total equipment and installation costs based on invoices and labor logs. The Center
will multiply the logged hours by the hourly rates charged by all participating contractors and ANR
staff to calculate total installation cost. The sum of the capital equipment costs and installation
costs will represent the net Emissions Packing initial cost. This cost will not include the capital or
installation costs associated with the flow monitors and other devices required for the verification
test.
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2.2.3. Phase II Emissions Packing Evaluation
The Phase II evaluation represents an extended period of performance testing and includes trends
analysis to project emissions beyond the period of the field test. Calculation of the payback period
based on these measurements and analysis is another key element of Phase II. Phase II will
represent up to 4 months operation with the emissions packing and include a total of 5 intensive
periods of manual measurements. A discussion of verification issues and actions for each Phase II
verification parameter are given in the following sections.
Document Annualized Gas Savings for Primary Baseline Operating Conditions
Case 1 and Case 2 gas savings for each idle period during the entire field test will be computed in
the same manner as for the Phase I testing (see Equations 1 and 2). Since the test may not span the
entire payback period, it will be necessary to project gas savings over this longer period. The most
direct method would be to simply compute an average gas savings over the study period (for Case
1 and Case 2) and multiply by the number of expected idle hours during a year. However, this
approach could yield an overly conservative estimate of annual gas savings - especially for Case 1
(see the "Average Gas Savings" in Figure 2).
It is expected that rod packing emissions (and possibly the leak rates for other components) will
increase over time. Since Case 1 gas savings are due entirely to eliminating rod packing leaks
during idle periods, neglecting an increasing leak trend would lead to an underestimate of gas
savings over an extended period of time. It is also possible that leak rates for components
contributing to Case 2 gas savings and losses could change over time. Thus, it is necessary to
consider any trend in emissions from all the components of interest that is revealed by the test data.
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To determine annual gas savings, an increasing trend in gas savings in the test data will be
projected in two straightforward ways: a conservative case, and a likely case. The conservative
case assumes that the gas savings rate after the test will not be lower than the gas savings rate at the
end of the test (unless a component is repaired or replaced). The likely case attempts, based on
available data, to project future increases in emissions, and take this into account in calculating gas
savings (see Figure 2).
Shaded areas represent gas savings
Study average gas savings
Measured during study
I I Other idle periods occuring during study
I I Conservative Projection
I I Likely Projection
~ Engine Running
P roj ec te d
S av i n g s
Measu red
Savings
a.
Sta rt Test
End of
E nd of
Payback
Ph ase 1 P hase 2
Figure 2. Methods of Projecting Gas Savings
Document Methane Emission Reduction
The net methane emission reduction is simply the cumulative gas savings calculated as described in
the previous sections. The measured leak rates for the major components will be reported to allow
users to assess the trends observed, use alternate assumptions and data interpretations, and apply
results of this evaluation to differing operating conditions as needed.
Calculate and Document Emissions Packing Payback Period
Payback occurs when the capital and operating costs (including cost of money) of the Emissions
Packing are balanced by the value of the gas saved. The operating and maintenance costs for the
Emissions Packing system are expected to be minimal, but will be documented and included in
payback calculations.
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Complete O&M logs on both the Emissions Packing and the compressor will be maintained. This
will include selected monitored parameters for the engine/compressor system, and manual logs of
key O&M activities. Table 3 lists the operational and maintenance parameters that will be
collected.
Table 3. Operational and Maintenance Data to be Collected During Testing
Description
Source of Data
Compressor, and Engine Operating Parameters Logged:
Engine rpm
Operating
Station
Data
Time
Rod temperature (both rods)
Unit discharge pressure
Unit discharge temperature
Unit suction pressure
Maintenance Requirements Logged:
Labor required to start/stop the system, conduct routine leak
checking on the entire Emissions Packing assembly, repair leaks,
respond to malfunctions, and perform Emissions Packing
adjustments
Operator logs
Equipment replacement or repair costs for failed units
Labor required to replace or repair failed units
Compressor/Engine downtime costs caused by failures in the
Emissions Packing apparatus
In the event that any of the Emissions Packing components fail and need repair or replacement,
ANR site personnel will log the purchase cost of each component, and the time and materials
expended in installing and checking the new components. Although unlikely, if failure in the
Emissions Packing system causes malfunctioning of the compressor or the engine, ANR site operators
will be consulted to help quantify the costs associated with the failure.
The procedure for calculating payback is outlined below.
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1. Total cost will be determined by adding the Emissions Packing capital costs, installation costs,
and O&M costs determined as outlined above. Capital costs will be amortized over the
payback period assuming a discount rate of return of 10 percent. Payback is achieved when the
total amortized cost = the value of the gas saved.
Total Cost = (Gas Savings) * (GP) (Eqn. 3)
Where: Total Costs = sum of capital, installation, O&M costs and cost of money
Total Gas Saved = net volume of methane (SCF) required to achieve payback
GP = gas price ($2/MCF)
2. Total gas savings over the payback period will necessarily include measured and projected values.
Savings will be projected in the same manner as described for determining annual gas savings. For
each case,
Total Gas Saved = Gas Saved Test + Gas Saved Est (Eqn 4)
Where: Gas SavedTest = total measured net volume of gas saved during the test period.
Gas SavedEst = total estimated net volume of gas to be saved after the test period.
The payback projections will include a conservative and a likely case. These will be calculated just
as described for projecting annual emissions reductions - except over the payback period.
2.2.4. Generalization of Results
The results of this test will be specific to the host site. In an effort to generalize the results to a
broader segment of the industry, the data collected during this verification will be used to estimate
the payback period for sites with emissions rates that differ from those encountered at the host site.
This will also provide a framework that others can use to determine Emissions Packing
performance for their site conditions.
To accomplish this, the Center will compile data from several studies of compressor emission
measurements including the GRI/EPA study discussed earlier (GRI, 1997), ongoing compressor
emissions characterizations being conducted by the Center, and more recent studies conducted by
Radian corporation and others. These data will be used to determine a range of emissions
characteristics for compressor rods, both running and idle, and other components examined in the
study. These data, along with the sealing performance measured at the host site (i.e., percent
reduction), will be used to determine payback estimates for 2 to 3 cases which span the range of
emissions observed in the industry.
16
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2.3.
SITE SELECTION, DESCRIPTION, AND EMISSIONS PACKING INSTALLATION
2.3.1. Site Selection and Description
The natural gas transmission engine/compressor selected to host this evaluation is operated by
ANR Pipeline Company. This station operates six Cooper-Bessemer engines (8 cylinder, 2000
Hp), each equipped with two reciprocating compressors operating in series (4,275 cubic inch
displacement, 4-inch rods). Geographic location was not seen as a significant factor in the
evaluation, but extremes of environment, very hot or very cold, were avoided.
The low speed engines at the test 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 functionality as most reciprocating compressors used now and planned for use in the future
within the transmission sector. Reciprocating compressors are the dominant types in use, although
newer compressor designs, such as screw-type, are beginning to be placed into service. The rod
packing system used at this station is typical of those being built or retrofitted within the industry.
The rod packing is essentially a dry seal system, using only a few ounces of lubricant per day.
Traditionally, wet seals, which use high-pressure oil to form a barrier against escaping gas, have
been employed. According to the natural Gas STAR partners, dry seal systems have come into
favor recently 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 seals.
In order to provide necessary experimental controls (see Section 2.2), the Emissions Packing will
be installed on one compressor on each of two engines. The packing on the second rod on each
engine will be replaced with a new packing at the same time that the Emissions Packing is
installed. The two engines are the same age and have similar operating hours (this is part of ANR's
operating practice). Actual operating hours on each engine will be logged at installation. ANR's
operation and maintenance practices are the same for each of the units.
2.3.2. Emissions Packing Installation and Operation
The host site presents a typical installation for the Emissions Packing system and no application
specific engineering is required. The Emissions Packing system is designed to accommodate the
17
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conditions (rod size, pressure, existing sealing system) at the test site. The Emissions Packing will
be installed in a modified packing case with new seals. A representative of France has confirmed
all necessary requirements. Once the Emissions Packing is installed, it should operate without
further attention. During the test, continuous monitors should indicate any change in capture
efficiency.
2.4. FIELD TEST OVERVIEW
The field testing will consist of periodic intensive periods of manual measurements which will be
correlated with idle periods that occur during the test period. Measurements of the rod leak rate on
the test and control rods will be used to quantify the gas savings from the rod packing leaks due to
the action of the Emissions Packing. These measurements allow quantification of the Case 1 gas
savings (for a compressor that remains pressurized while shut down). Additional manual
measurements are necessary to quantify leak rates for the unit valves, blow-down valve, pressure
relief valve and miscellaneous components that make up additional data needed to quantify Case 2
gas savings (for a compressor that would normally blow-down prior to installing the Emissions
Packing).
2.4.1. Rod Packing Leak Rate Measurements
At the test compressor, emissions from the packing case vent and fugitive emissions from around
the rod are both vented into the distance piece or doghouse and then vented to atmosphere through
the doghouse vent. The doghouse vent and oil drain are the only paths by which the leaking gas
can leave the doghouse. For the test, the doghouse drain will be sealed using a liquid trap so that
all emissions will be forced out the doghouse vent.
To measure these emissions, flow meters will be installed on the doghouse vent lines for each of
the compressors to be tested. The meters must present a minimal restriction to flow in order not to
influence the leak rate. They must also have a wide range, and be resistant to oil vapor present in
the emissions. The meters selected for the test are a type of rate meter (similar to a rotameter)
designed for measuring methane emissions from sludge digesters, landfills, and other low pressure
applications. They have wide range (25:1 turndown), a very low pressure drop (2 inches water)
and should not be affected by oil mist present in the emissions. The meters are factory calibrated
18
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and scaled to provide a direct reading in cfm methane. The Center will check the calibration of the
meters against a certified laminar flow element standard before and after each intensive
measurement period. The meter reading will require correction to standard conditions (scftn). This
will be based on ambient pressure and gas temperature readings obtained concurrent with the
measurements. During installation and during periodic intensive measurement periods, the
methane concentration of the gas leaking from the doghouse will be measured with a portable
hydrocarbon analyzer.
2.4.2. Component Leak Rate Measurements
Manual measurements will be made of leak rates for the unit valves, blow-down valve, pressure
relief valve and miscellaneous components.
Figure 3. Unit Valve Sampling Port
The leak rate for the unit valves will be measured at an existing port located immediately
downstream of the unit valve in the suction line to the compressor (see Figure 3). With the
compressor shutdown and blown-down, any unit valve leak will exit through the opened port. The
19
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leak rate will be measured using a standard pitot mounted in a flow tube (see Section 5 for details
of operation and calibration).
The leak rates for the blow-down valve and pressure relief valve will be made with the unit shut
down and pressurized. The leak rate for the blow-down valve will be measured at the flange
located at the exit of the valve (see Figure 4). To make this measurement, it will be necessary to
unbolt the flange. The flange will then be separated about 1 inch, and a disk will be inserted and
clamped into place. The disk will capture the leak and direct it outward. The disk will be made of
high-density polyethylene about 1 inch thick and machined to fit the flange. A borehole will be
provided radially into the disk that will allow any leaking gas to escape for measurement using the
flow tube.
Blowdown
Vailve Flange
Jr
Figure 4. Blow-down Valve Sampling Location
20
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The pressure relief valve normally vents through a 4 inch standpipe extending to the roof of the
compressor building. The simplest way to measure the leak rate is to cap the standpipe, allowing a
port to channel emissions for measurement using a flow tube.
The miscellaneous components at the test site consist of metering ports and valves used to recover
gas to the fuel system during shutdowns (the host station normally vents to the fuel system during
shutdowns). Significant leaks are not expected at these locations; however, all components will be
soap screened and any leaks identified will be quantified using the EPA protocol tent/bag method.
The manual leak rate measurements will require scheduled shutdowns that proceed as follows:
Unit shutdown - remains pressurized, leak rates for the pressure relief valve,
blow-down valve and miscellaneous components will be measured (several
hours)
Measure rod packing leak rates on test and control rods
Unit blown-down, unit valve leak rate measured (about one hour)
Unit brought back on line
Nearly one full day will be needed to conduct this suite of measurements.
The station has agreed to a limited number of scheduled shutdowns for the purpose of conducting
the measurements described above. These will only be used to characterize the quantities as
discussed above, and will not contribute to the gas savings - which will be based on idle periods
during normal operation. It is proposed to conduct 3 such scheduled shutdowns during the first
week of the test, after installation of the Emissions Packing and after the packing has had time to
stabilize (approximately 48 hours). In order to address changes over time, this series of
measurements will be repeated on four other occasions at approximately 2 weeks, 1 month, 2
months, and 4 months after installation. Thus, the manual measurements will be repeated a total of
9 times in Phase I, and a total of 15 times for Phase I and Phase II combined in order to capture the
magnitude and variability of the various quantities involved.
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2.5.
SCHEDULE OF ACTIVITIES
A site survey visit has been completed and preliminary emissions measurements have been
obtained. Field testing is scheduled to begin in June of 1999. Allowing time for data analysis to be
completed, a draft Phase I Report should be available for review in late August, 1999. All field
activity should be completed by October of 1999. A draft Phase II Report should be available no
later than December 31, 1999. A final Phase I Report should be available for distribution in
November, 1999 and a final Phase II Report should be available for distribution in February, 2000.
3.0 DATA QUALITY OBJECTIVES
Data quality objectives state the values of key data quality indicators for each measured quantity.
These objectives must be achieved in order to draw conclusions from the measurements with the
desired level of confidence. The process of establishing data quality objectives for measurements
starts with determining the desired level of confidence in the primary verification parameters (e.g.,
confidence level in the verified payback period).
The next step is to identify all measured values impacting the primary verification parameters, and
determine the error allowed. Formal error propagation techniques can help to systematize these
determinations. With error propagation, the cumulative effect of all measured variables on the primary
data quality objective can be estimated. This allows individual measurement methods to be chosen
which perform well enough to satisfy the data quality objective for the primary verification parameter.
A primary quantitative objective for this study is to establish the payback period associated with
installation and use of the France emissions packing. Based on meetings with the Stakeholders, a
payback period of three years would represent acceptable performance. An error in this value of
about + 3 to 4 months, or about 10 percent, is used as a basis in determining the data quality
requirements.
Payback occurs when the total cost of the Emissions Packing (amortized capital and installation
costs, and operation and maintenance costs) equals the savings that the system provides (net gas
loss prevented). For the field test, the costs will be based on actual costs and the errors are zero.
Gas loss reduction will be measured directly during the study, then projected for the periods
immediately before and after the test is done. Specific data quality objectives address the error in
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the direct measurements only; however, a discussion of the errors in the projections is also
provided below.
3.1. ROD LEAK MEASUREMENTS
For a three year payback to occur for Case 1, the gas savings rate would have to average about 3.8
cfm - or 1.9 cfm per rod (assuming $4,000 total cost for two rods, gas value of $2/MCF, and 33
percent downtime). This implies a minimum gas savings rate of interest of about 0.2 cfm per rod
(-10 percent of 1.9 cfm). However, based on survey measurements, the running leak rates could be
as low as 0.1 scfm or less. In order to adequately quantify these baseline emissions, more sensitive
meters are required. To span the full range of interest (up to at least 2 scfm per rod), dual sets of
meters (high range and low range) will be required.
The low range meters span 0.75 to 22.5 scfh (0.01 to 0.375 scfm) methane. The high range meters
span 7.5 to 187.5 scfh (0.125 to 3.125 scfm) methane. The maximum error in both meters is + 2
percent. As discussed above (see Equation 1), the gas savings for each idle period will be taken as
the difference between the leak rate on the test and control rods. By error propagation, the total
error in the difference is the sum of the absolute error in each measurement (in measured units).
Thus, the total error in low range differences is 0.9 scfh (0.015 scfm) methane. The total error in
high range differences is 7.5 scfh (0.12 scfm) methane. For comparisons between high range and
low range measurements, the total error is 4.05 scfh (0.07 scfm) methane.
These errors are all below the minimum leak rate of interest and meet the 10 percent data quality
objective for a three year payback. The low range measurements provide additional capability to
meter very small emissions.
3.2. COMPONENT LEAK RATE MEASUREMENTS
Measurements of the leak rate for the blow-down valve, pressure relief valve and unit valves will
be made using a calibrated flow tube. For the miscellaneous components, it may not be possible to
effectively channel the leaking gas to the flow tube. In such cases, EPA's protocol tent/bag method
will be used to quantify the leak rate.
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The flow tube consists of a 0.125 inch standard pitot (Dwyer model 166-12) mounted in the center
of a 1 inch diameter straight run of pipe. The differential pressure across the pitot is proportional to
velocity and is metered by a precision digital manometer. The minimum flow velocity that can be
measured is 25 fpm. This corresponds to a flow of about 0.15 cfm in the 1 inch pipe. The entire
apparatus will be calibrated specific to methane against a certified laminar flow element transfer
standard (traceable to NIST). The calibration curve thus generated will be used to obtain flow
values from the raw pressure differential readings. The precision and accuracy of the flow tube
will be based on the calibrations. Estimated accuracy (based on nominal values) is + 2 percent of
reading.
EPA's tent/bag method is nominally accurate to within + 20 percent (EPA 1993), but has been
shown to be capable of better than + 10 percent when carefully applied (SRI 1996). Thus, the
methods should be capable of producing data at or near the desired level of confidence.
As a practical matter, the real limitation on the accuracy and the representativeness of the manual
measurements is their relative infrequency. To counteract this, the manual measurements will be
repeated in triplicate during each of the three intensive measurement periods planned for the
overall test (Phase I and Phase II).
The other quantity to be considered for Case 2 is the blow-down volume. This will be quantified
based on the volume of piping and manifolds in the compressor system and will be accurate within
the piping specifications and pressure sensor accuracy. Unit pressure (measured at the station) will
be used to convert the volume to scfm.
3.3. PROJECTIONS
As discussed above (Section 2.2), projections beyond the test period will include a conservative
case and a likely case. In both cases, estimates for the number and duration of idle periods will be
based on the previous year's operation for the test unit. In the conservative case, emissions
projections are straight lined from the end of the test period and the uncertainties are small - no
more than uncertainty in the final set of measurements used for the projected value. In the likely
case, projections will be based on the trends in the measured data. In this case, the uncertainty may
be estimated based on the fit of the projected curve to the measured data.
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4.0 DATA QUALITY INDICATORS
This section specifies data quality indicators that will be used as measures of data quality for the
test data and states how values for each indicator will be determined through calibrations, QC
checks, and other appropriate measures. This is presented in Table 6.
Table 6. Data Quality Indicators
Measurement
Method
Range
Completeness/
Frequency
Precision/
Accuracy
How Verified/
Determined
Doghouse Vent
Emissions (Rod
leaks)
Variable area
rate meters
(MEM
Rangemaster)
0.01 to 0.375 scfin
(low range)
0.125 to 3.125
scfin (high range)
15 total
measurements
(5 sets of 3)
2 % FS
Calibration check
against NIST
traceable LFE
Unit Valve Leak
Rate
Flow Tube
0.1 to 4 scfin
methane
15 total
measurements
(5 sets of 3)
5 %
Calibration against
NIST traceable LFE
Blow-down
valve leak rate
Flow Tube
0.1 to 4 scfin
methane
15 total
measurements
(5 sets of 3)
5 %
Calibration against
NIST traceable LFE
Pressure relief
valve leak rate
Flow Tube
0.1 to 4 scfin
methane
15 total
measurements
(5 sets of 3)
5 %
Calibration against
NIST traceable LFE
Misc.
components leak
rate
EPA Tent/Bag
0.1 to 4 scfin
methane
15 total
measurements
(5 sets of 3)
10 to 20%
Repeat
measurements
5.0 SAMPLING/ANALYTICAL AND QA/QC PROCEDURES
5.1. ROD LEAK MEASUREMENTS
Emissions Packing leak prevention is determined using a flow meter on each doghouse vent to
measure any leaks. The meters selected for the test are a type of rate meter (similar to a rotameter)
designed for measuring methane emissions from sludge digesters, landfills, and other low-pressure
applications. Since they are rate meters, they will require external temperature and pressure
correction to obtain flow readings at standard conditions. Since the meters will be vented to
atmosphere, local barometric pressure data will be used to correct for pressure. The temperature of
the sampled gas will be checked during each measurement and used to correct for temperature.
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The flow meters will be factory calibrated against a primary volume standard (spirometer).
Calibration certificates will be supplied. The meters are rugged and reliable and should not require
re-calibration over the duration of the study In addition. The calibrations will be checked before
each intensive measurement period.
5.2. COMPONENT LEAK RATE MEASUREMENTS
A general description of the manual measurements of the leak rates for the unit valves, blow-down
valve, pressure relief valve, and miscellaneous components is given in Section 2.4. The manual
leak rate measurements will require scheduled shutdowns that proceed as follows:
Unit shutdown - remains pressurized. Leak rates for the pressure relief valve,
blow-down valve and miscellaneous components will be measured (several
hours). The gas recovery system will be disabled for the testing.
Measure rod packing leak rates on test and control rods (one hour)
Unit blown-down, unit valve leak rate measured (about one hour)
Unit brought back on line
Nearly one full day will be needed to complete this suite of measurements. The station has agreed
to a limited number of scheduled shutdowns. It is proposed to conduct three such scheduled
shutdowns during the first week of the test, after installation of the Emissions Packing and after the
new packings have had time to stabilize (approximately 48 hours). In order to address changes
over time, this series of measurements will be repeated on two other occasions in Phase I (at 2
weeks and 4 weeks), and 2 additional occasions during Phase II (at 2 months and 3 months). The
manual measurements will be repeated a total of 15 times in order to capture the magnitude and
variability of the various quantities involved.
Detailed procedures for each type of measurement follow.
5.2.1. Blow-down Valve, and Pressure Relief Valve
The leak rates for the blow-down valve and pressure relief valve will be made with the unit shut
down and pressurized. The leak rate for the blow-down valve will be measured at the flange
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located at the exit of the valve (see Figure 3). To make this measurement it will be necessary to
unbolt the flange. The flange will then be separated about 1 inch and a disk will be inserted and
clamped into place. The disk will capture the leak and direct it outward radially. The disk will be
made of high-density polyethylene about 1 inch thick and machined to fit the flange. A borehole
will be provided radially into the disk that will allow any leaking gas to escape for measurement
using the Flow Tube. The procedure is as follows:
Shutdown the unit, leaving pressurized. Vent gas recovery system should be
disabled.
Record suction and discharge line pressures (obtain from station operator).
Unbolt the flange and jack up the blow-down vent pipe approximately 1-2
inches.
Insert the leak capture disk and clamp into place.
Complete measurement of leak rate.
Log all results in the field data log.
The pressure relief valve normally vents through a standpipe extending to the roof of the
compressor building. The simplest way to measure the leak rate is to cap the standpipe, allowing a
port to channel emissions for measurement using the Flow Tube. The procedure is as follows:
The unit should still be shut down and pressurized.
Record suction and discharge line pressures (obtain from station operator).
Ascend to the roof of the compressor building - observing station safety rules
(tie offs).
Cap vent pipe with ported sampling cap.
Complete measurement of leak rate.
Log all results in the field data log.
Quality control for the blow-down and pressure relief valve measurements consists of calibrating
the flow tube prior to each series of measurements. The flow tube calibration is a direct
comparison against a NIST traceable laminar flow element, specific to methane, conducted at no
fewer than 5 points spanning the flow range of interest (0.15 scfin to 5 scfin methane).
Documentation of all calibrations will be maintained on file.
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5.2.2. Miscellaneous Components
The miscellaneous components at the test site consist of metering ports, the bypass valve and the
vent gas recovery system used to recover gas to the fuel system during shutdowns (the host station
normally vents to the fuel system during shutdowns). These tests will be conducted with the unit
shut down and fully pressurized. Significant leaks are not expected at these locations; however, all
components will be soap screened and any leaks identified will be quantified using the EPA
protocol tent/bag method (EPA 1993). Sampling/analytical and QA/QC procedures for this method
are published elsewhere (EPA 1993). The basic principle is to measure the methane concentration
in a known volume of clean air and compute the leak rate as the product of the methane
concentration and the sampling rate.
A Bascom-Turner CGI-201 methane analyzer will be used to determine methane concentration.
The CGI-201 is very stable and need only be calibrated prior to each set of intensive
measurements. Calibration will be done in the Center's Research Triangle Park, NC laboratory
facility using certified methane standards at 2.5, 25, 50, and 100 percent methane. Field checks
consist of an automated zero cycle conducted prior to each set of measurements.
5.2.3. Unit Valves
After the leak rates for the blow-down valve, pressure relief valve, and miscellaneous components
have been measured, the unit will be blown-down to measure the combined leak rate from both unit
valves. Whenever the unit is shut down, the suction and discharge lines are connected via a bypass
valve and line. The combined leak rate for the unit valves will be measured at an existing port
located immediately downstream of the suction side unit valve. With the compressor blown-down,
the combined leak from both unit valves will exit through the sampling port. The leak rate will be
measured with the flow tube. The procedure is as follows.
Blow-down the unit (station operator).
Open the sampling port.
Complete measurements of the leak rate.
Log all results in the field data log.
Quality control for the unit valve measurements is the same as for the other manual measurements
using the flow tube for quantification.
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5.3. DATA ACQUISITION
Direct field measurements will be conducted manually and results will be logged on field data
forms (see Table 7).
In addition to the direct measurements, data on engine and compressor operation that relate to the
test are stored in the station computer and will be retrieved and transmitted to the Center
periodically. Table 8 lists all parameters that will be collected and stored and their purpose.
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Table 7. Field Data Form
Field Data Form - France Emissions Packing Measurements
Rod Packing Leaks - MEM
Rangemaster
Enc
ine 1
Eng
ine 2
Test Rod
Control Rod
Test Rod
Control Rod
Range Low/High
Gas Temp (C)
Bar. Pressure (mmHg)
Leak Rate (cfm)
Leak Rate (scfm)
Measure with Unit Pressurized - Running
Rod Packing Leaks - MEM
Rangemaster
Eng
ine 1
Engine 2
Test Rod
Control Rod
Test Rod
Control Rod
Range Low/High
Gas Temp (C)
Bar. Pressure (mmHg)
Leak Rate (cfm)
Leak Rate (scfm)
Measure with Unit Pressurized - Idle
Component Leaks - Flow
Tube
Blow Down Valve
Pressure Relief Valve
Unit Valves (combined)
Engine 1
Engine 2
Engine 1
Engine 2
Engine 1
Engine 2
Gas Temp (C)
Bar. Pressure (mmHg)
Velocity (fpm)
Leak Rate (scfm)
Measure with Unit Pressurized - Idle
Unit De-pressurized - Idle
Misc. Components - Tent/Bag
Component Desc./ Engine
No.
Amb. Temp
(C)
Press.
(mmHg)
Bag flow
(Ipm)
Cone. (%
methane)
Leak Rate
(Ipm)
Leak Rate
(scfm)
Measure with Unit Pressurized - Idle
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Table 8. Data Record Contents and Significance
PARAMETER
SIGNIFICANCE
Date
Time
Rod Seal #1 Leak Rate
Leak rate
Rod Seal #1 Gas Temperature
Temp. Correction for #1 leak rate
Rod Seal #2 Leak Rate
Leak rate
Rod Seal #1 Gas Temperature
Temp. Correction for #2 leak rate
Barometric pressure
Pressure correction for #l/#2 leak rates
Engine RPM
Unit on/off status
Unit Suction Pressure
Unit operating status
Unit Discharge Pressure
Unit operating status
6.0 DATA REDUCTION, VALIDATION, AND REPORTING
6.1. DATA REDUCTION
This section documents calculations that will be used to obtain final results from raw
measurements.
6.1.1. Rod Leak Measurements
The flow meters used to measure rod emissions will be calibrated specific to methane at 70 degrees
F. and 1 atmosphere pressure. To adjust for variations in gas temperature and pressure and correct
to standard conditions.
scfin = cfm * (P/760 * 294.26/T)A0.5
where P is the absolute barometric pressure (torr) at the site and T is the gas temperature (in
Kelvins). The exponent of 0.5 (square root) is necessary due to the physics of rate meters.
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6.1.2. Component Measurements
Leak rates for the blow-down valve, pressure relief valve, and unit valves are determined using the
flow tube which measures sample flow and concentration. The flow will be calibrated specific to
methane in the laboratory and the calibration parameters (slope and intercept) will be used to
convert directly from the output (fpm) to flow rate (in scfm) as follows.
scfm = v * m + b
where v is the pitot output, m is the slope of the calibration curve, and b is the intercept.
If miscellaneous components are found to be leaking (using soap solution), then the leak rates will
be quantified using EPA protocol (Method 21) tent/bag method. The leak rate is found as the
product of the methane concentration and the sampled flow rate. The methane concentration will
be read directly from a Bascom-Turner CGI-201 analyzer calibrated specific to methane.
6.1.3. Gas Savings and Payback period
Formulae for calculating gas savings (Case 1 and Case 2) and for determining the payback period
are given in Section 2.2 of this plan.
6.1.4. Unit Conversions
Engineering units in common use at the test site and within the host industry will be used for
reporting and summarizing results. For pressure, the units are psi or inches water column. For
flow, the units are cfm and scfm (1 atmosphere, 70 degrees F or 294.26 K). For gas velocity, the
units are fpm. For concentration, percentage by volume or ppm are used.
6.2. DATA REVIEW AND VALIDATION
Calibrations and quality control checks for each measurement are described in Section 5 -
Sampling and Analytical Procedures. Table 9 summarizes the calibrations and quality control
checks to be performed. Upon review, all data collected will be classified as either valid, suspect,
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or invalid. In general, valid results are based on measurements meeting data quality objectives.
All data are considered valid unless a specific performance limit is exceeded or operational check
is failed.
It is often the case that anomalous data are identified in the process of data review. All outlying or
unusual values will be investigated as fully as possible using test records and logs. Anomalous
data may be considered suspect if no specific operational cause to invalidate the data are found. All
data - valid, invalid, and suspect will be included in the final report. Report conclusions will be
based on valid data only. The reasons for excluding any data will be justified in the report. Suspect
data may be included in the analyses, but may be given special treatment as specifically indicated.
All continuous sensor data will be reviewed on a daily basis. All anomalous or outlying values will
be identified and investigated to find a cause for the unusual condition. Manual measurements data
will be reviewed in the field as they are collected and any anomalous conditions will be
documented in field log book and, if possible, corrected.
Table 8. Summary of Calibrations and QC Checks
Measurement
Cal/QC Check
When Performed/
frequency
Expected or
Allowable
Result
Response to Check
Failure or Out of
Control Condition
Rod Leak Rate
MEM Meter
Calibration
Check
Prior to each
measurement period
±5 %
Identify cause of
discrepancy and correct
MEM Meter
Calibration
Prior to shipping
Initial calibration
Replace meter
Component Leak
Rates
Flow Tube
Calibration
Prior to each
measurement period
Obtain
calibration slope
and intercept
Identify cause of any
problem and correct
EPA Method 21
Methane
Analyzer
Calibration
Prior to each
measurement period
Set to standard
N/A
Flow System
Calibration
Prior to each
measurement period
Obtain
calibration slope
and intercept
N/A
Flow System
Leak Check
Each measurement
No leak
Identify cause of any
problem and correct
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6.3.
DATA ANALYSIS AND REPORTING
After data reduction, review and validation, the primary Phase I data analyses will include the
following:
Document initial gas savings (methane emission reduction) for primary
baseline operating conditions
The gas savings and methane emission reduction is the amount of gas that is prevented
from leaking to the atmosphere either by the static seals themselves (Case I) or by the
seals and changes in shut down procedure associated with installation of the seals
(Case II).
Document capital, installation, and shakedown requirements and costs
This is a broad assessment of effort and costs required to install the Emissions Packing
and ensure that it is operating properly. Any problems encountered during installation
and shakedown - and their resolutions will be described. Capital and installation costs
will be based on the actual installed cost for the system. For the test, flow sensors are
being installed that might not be installed in a normal situation. Once the system is
operational, host site personnel will be interviewed to determine whether flow sensors
to document gas savings would be considered necessary in a permanent installation.
The following is a preliminary outline of the content of the Phase I Verification Report.
Preliminary Outline
France Emissions Packing Seal System
Phase I Verification Report
Verification Statement
Section 1 Verification Test Design and Description
Emissions Packing Description
Site Selection, Description, and Emissions Packing Installation
Verification Parameters and Their Determination
Initial gas savings (methane emission reduction) for primary baseline
operating conditions
Installation and Shakedown Requirements
Initial Capital and Installation Costs
Sampling and Analytical Procedures
Continuous Measurements
Manual Measurements
Data Acquisition System
Quality Assurance and Quality Control Measures
Calibration Procedures
Quality Control Checks, Audits, and Corrective Actions
Data Reduction
Data Validation
Data Analysis and Reporting
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Section 2 Phase I Verification Results and Evaluation
Initial gas savings (methane emission reduction) for primary baseline
operating conditions
Installation and Shakedown Requirements
Initial Capital and Installation Costs
Data Quality Assessment
Section 3 Additional Technical and Performance Data From France
References
The Phase II report will include key data from the Phase I report. The Phase II report will
incorporate the results from the entire evaluation process, and will focus on longer-term
performance of the system and the payback period. Phase II verification parameters include:
Annualized gas savings for primary baseline conditions
Methane emission reduction
Calculate Emissions Packing payback period
7.0 AUDITS
An internal systems audit is planned for this test. The audit will be conducted by SRI's
independently managed QA staff. This will include field verification, procedural, and
documentation components using this plan as the basis for the audit. An external audit may be
performed at EPA's discretion by EPA QA staff or a qualified contractor. A performance audit on
sensors used in the study is not considered necessary since all devices will be laboratory certified
before each intensive measurement period. An internal audit of data quality will be conducted
once data collection and analyses are complete. The final report will contain a summary of results
from all audits.
8.0 CORRECTIVE ACTION
Table 9 in Section 6.2 lists allowable values for each of the calibrations and quality control checks
and also indicates actions to be taken in response to an out of control condition. Other issues may
arise that require corrective actions or plan changes to ensure that data quality objectives are met.
SRI's quality management plan provides general procedures for corrective action that will be
followed in such instances.
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9.0 PROJECT ORGANIZATION
Southern Research Institute's Greenhouse Gas Technology Verification Center has overall
responsibility for planning and ensuring successful implementation of the verification test. France
is providing the Emissions Packing technology, equipment, and engineering for the test installation.
ANR Pipeline is providing access to the host site, and logistical and manpower assistance in the
installation and operation of the Emissions Packing. Good working relationships have been
established between the Center, France, and ANR which have proved valuable in the planning up
to this stage. All parties have signed a formal agreement (documented in the Letter of
Commitment and associated documents) specifying details of financial, technical, and managerial
responsibilities.
EPA's APPCD is the sponsor of the ETV Greenhouse Gas Pilot and is providing broad oversight
and QA support for the project. The project organization is presented in Figure 5.
France Compresor Products
Jim Maholic
ANR Pipeline
Earle Prince
Mark Romzek
Southern Research Institute
QA Staff
Scott Bell
Southern Research Institute
ETV GHG QA Coordinator
Brian Phillips
Southern Research Institute
ETV GHG Technical Staff
Eric Ringler
Bill Chatterton
EPA
ETV GHG Pilot Manager
EPA - APPCD
David Kirchgessner
EPA
ETV GHG QA Manager
EPA - APPCD
Kaye Whitfield
Southern Research Institute
QA Manager
Leslie Schnoll
Southern Research Institute
ETV GHG Center Director
Stephen Piccot
ETV GHG Center Deputy Director
Sushma Masemore
Figure 5. Project Organization
10.0 TEST PROGRAM HEALTH AND SAFETY
This section applies to Center personnel only. Other organizations involved in the project have
their own health and safety plans - specific to their roles in the project.
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SRI staff will comply with all known ANR, state, local, and Federal regulations relating to safety at
ANR's Celestine compressor station. This includes use of personal protective gear (flame resistant
clothing, safety glasses, hearing protection, safety toe shoes) as required and completion of site
safety orientation (site hazard awareness, alarms and signals, etc.).
Other than normal industrial hazards, the most significant hazard at the Station is the potential for
explosive concentrations of natural gas. SRI plans to use only intrinsically safe apparatus in the
compressor building. Should use of any equipment not so rated be required, SRI will not use this
equipment until advised by site personnel that it is safe to do so.
Some test procedures will require that special safety precautions be observed. In particular, when
conducting manual sampling of the blow-down valve leak rate, the automated blow-down valve
control should be disabled to prevent a blow-down during sampling.
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11.0 REFERENCES
US Environmental Protection Agency. Appendix A, NSPS Test Methods. 40CFRPart60. 1999.
US Environmental Protection Agency. Natural Gas STAR Program. World Wide Web
(www, epa.gov. gasstar).
US Environmental Protection Agency. Protocol for Equipment Leak Emissions Estimates, EPA-
453/R-93-026, June 1993.
Gas Research Institute/US Environmental Protection Agency. Methane Emissions from the
Natural Gas Industry. GRI-94/0257-EPA-600/R-96-080. June, 1996.
Gas Research Institute. Documentation of Existing Rod Packing Technology and Emissions. GRI-
97/0393. December 1997.
Howard, Touche. Methane Emissions from Natural Gas Customer Meters: Screening and
Enclosure studies. Indaco Air Quality Services, July 1992.
Hummel, Kirk E., Lisa M. Campbell, and Matthew R. Harrison. Methane Emissions from the
Natural Gas Industry, Volume 8: Equipment Leaks. GRI-94/0257.25. Gas Research Institute.
Chicago, IL. June 1996.
Lott, R.A., Howard, T., and Webb M. New Technology for Measuring Leak Rates. American Gas
Association Operating Proceedings. 1995.
Lott, Robert A., Indaco Air Quality Services, Inc. GRI Hi-FlowTM Sampler for Leak Detection
and Measurement, June 1998.
Southern Research Institute. Evaluation of the High Volume Collection System (HVCS) for
Quantifying Fugitive Organic Vapor Leaks, EPA/600/SR-95/167, February 1996.
Southern Research Institute. Environmental Technology Verification Greenhouse Gas Technology
Verification Quality management Plan. Research Triangle Park, NC. October, 1998.
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