EPA Project Report No. 73-SFA-3B
CD
AIR POLLUTION
EMISSION TEST
O
ifi,
FINAL REPORT
MISSISSIPPI CHEMICAL CORPORATION
PASCAGOULA, MISSISSIPPI
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
Office of Air and Waste Management
Office of Air Quality Planning and Standards
Emission Measurement Branch
f Research Triangle Park, North Carolina
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FINAL REPORT
CONTINUOUS MEASUREMENT OF
SULFUR DIOXIDE EMISSIONS
EPA Project Report No. 73-SFA-3
MISSISSIPPI CHEMICAL CORPORATION
PASCAGOULA, MISSISSIPPI
Prepared For
The Environmental Protection Agency
United States Government
Contract No. 68-02-0232
Task No. 26
ESE Project No. 73-011-026
environmental science and engineering, inc.
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FINAL REPORT
REPORT NO: . 73-SFA-3
PLANT TESTED: Mississippi Chemical Corporation
Pascagoula, Mississippi
EMISSIONS FROM: No. 2 Sulfuric Acid Plant
TESTOR:
Environmental Science and Engineering, Inc.
Post Office Box 13454
University Station
Gainesville, Florida 32604
CONTRACT NO: 68-02-0232, Task Order No. 26
environmental science and engineering, inc
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TABLE OF CONTENTS
Page Number
1.0 INTRODUCTION 1
2.0 PERFORMANCE AND MAINTENANCE OF THE CONTINUOUS
MONITORING SYSTEM 4
2.1 PERFORMANCE CHARACTERISTICS OF THE CON-
TINUOUS MONITOR 4
2.2 LONG-TERM PERFORMANCE AND MAINTENANCE OF THE
CONTINUOUS MONITORING SYSTEM 7
3.0 PROCESS OPERATION 10
4.0 OPERATIONAL COSTS 11
APPENDICES
APPENDIX A - PROCEDURES FOR DETERMINING ACTUAL
PERFORMANCE OF THE MONITORING SYSTEM
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LIST OF TABLES
Page Number
Table 1. Determination of Factor to Convert Monitoring
Units Into Units of the Applicable Emission
Standard. 5
Table 2. Performance of the Sulfur Dioxide Continuous
Monitor. 6
Table 3. Cost and Level of Effort Based Upon Procurement,
Installation, and Operation by a Service
Organization (e.g., an Engineering Consultant
Firm)9 12
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1.0 INTRODUCTION
As part of the Continuous Monitoring Project directed by the Emission
Measurement Branch, Office of Air Programs, U.S. Environmental Protec-
tion Agency (EPA), an evaluation of sulfur dioxide emissions from a
sulfuric acid plant and of a continuous sulfur dioxide monitor for
stationary sources was conducted by Environmental Science and Engineer-
ing, Inc. (ESE). The evaluations included conducting performance tests
on the continuous monitor and analyzing the long-term performance of
the plant over a six-month period.
The continuous sulfur dioxide measurement system evaluated was in oper-
ation at the No. 2 sulfuric acid plant of the Mississippi Chemical
Corporation (MCC) in Pascagoula, Mississippi. The system continuously
measures and records the sulfur dioxide concentration in the effluent
gases of the plant.
The purpose of the performance tests was to evaluate the operation of
the continuous sulfur dioxide measurement system in regard to certain
"performance specifications." General requirements for continuous
monitoring and recording of sulfur dioxide emissions from sulfuric
acid plants were initially published by the EPA in the Federal Register
(Vol. 36, No. 247, Subpart H, Section 60.84, December 23, 1971, Wash-
ington, D.C.). More recently, specific monitoring requirements, per-
formance specifications and procedures for determining whether a
continuous monitoring system meets the performance specifications
have been proposed by the EPA for monitors of sulfur dioxide emissions
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from stationary sources (Federal Register, Vol. 39, No. 177, Part II,
September 11, 1974, Washington, D.C.). The required performance tests
were conducted during the period from September 10-14, 1973, and as
such occurred before the suggested methods were published by EPA. The
testing procedure adhered to in the operational testing period was
very similar to that specified in the above Federal Register. However,
the performance specifications by which the sulfur dioxide monitor was
evaluated in the interim report have been significantly modified. To
determine the effects of these changes on the performance evaluation
of the continuous monitor, the monitor was re-evaluated according to
the new specifications, using the data contained in the interim report.
The re-evaluation is presented in this report.
A continuous sampling program utilizing the continuous sulfur dioxide
monitor was conducted for a 6-month period. The purpose of the con-
tinuous monitoring was to evaluate the long-term emission performance
of the MCC sulfuric acid plant and long-term performance and maintenance
requirements of the continuous monitor. The 6-month period extended
from September, 1973 through March, 1974.
Procedures, results and discussion of the performance testing are con-
tained in the interim report under this contract, entitled "Source
Test Report, Measurement of Sulfur Dioxide Emissions, Mississippi
Chemical Corporation, Pascagoula, Mississippi, Report No. 73-SFA-3."
The long-term performance of the sulfuric acid plant in regard to its
sulfur dioxide emissions will be presented in the "Data Summary Report"
for this project task order. Statistical and analytical data summaries
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will also be contained in this report. The long-term performance
characteristics and operational problems associated with the continuous
sulfur dioxide monitor are discussed herein.
The continuous sulfur dioxide monitor evaluation project, of which this
report is part, was in general a marked success. A wealth of knowledge
was gained concerning the instrument performance and maintenance, over
both the short- and long-term. The sulfur dioxide monitor proved to
be a reliable, low maintenance, easy to operate system and complied
with most of the new, more stringent, EPA performance guidelines.
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2.0 PERFORMANCE AND MAINTENANCE OF THE CONTINUOUS MONITORING SYSTEM
2.1 PERFORMANCE CHARACTERISTICS OF THE CONTINUOUS MONITOR
The interim report under this contract task order evaluated the con-
tinuous sulfur dioxide monitoring system in different terms than those
proposed in the aforementioned September 11, 1974 issue of the Federal
Register. Since these new specifications for the performance of con-
tinuous monitoring systems seem to be more stringent than the former
guidelines, it is of interest to compare and re-evaluate the system
in regards to the proposed guidelines.
The data contained in the interim report was used to determine the
actual performance of the sulfur dioxide monitor in terms of the pro-
posed EPA specifications. Since a portion of the specifications is
expressed as a percentage of the relevant emission standard, it was
first necessary to formulate a conversion factor relating output of
the continuous monitor, in parts per million (ppm), to emission rate,
expressed as pounds of sulfur dioxide per ton of sulfuric acid produced
(Ib/ton ^SO^). The pertinent parameters necessary for the conversion
and the conversion factor for each test period are listed in Table 1.
Averaging of all the testing period factors resulted in a conversion
factor of 0.01482 Ib/ton H^SO./ppm - ppm as read from the sulfur dioxide
analyzer. This factor was used in converting the monitoring data units
to units of the applicable standard.
Table 2 summarizes the actual performance of the sulfur dioxide analyzer.
The table also lists the proposed Federal EPA performance specifications,
and the pertinent parameters used in obtaining the performance figures.
The methods used in determining the performance specifications, including
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Table 1. Determination of Factor to Convert Monitoring Units
Into Units of the Applicable Emission Standard.
en
i
Date
9/11/73
9/12/73
9/13/73
ppm = parts
Average '
Manual Measured S02
Test Emissions
No. (ppm)
1
2
3
4
5
6
7
8
9
per million
317.0
342.5
303.0
358.5
338.5
310.0
392.5
402.5
362.5
Average
Flow Rate
(SCFM)
91252
86226
87933
81049
91445
88121
88442
88450
88469
Average S02
Emission Rate
(Ib/hr)
284
290
262
285
304
268
341
349
315
H2S04
Production
Rate
(tons/day)
1505
1505
1505
1507
1507
1507
1509
1509
1509
S02
Emission
Rate
(Ibs/ton H.S04)
4.53
4.62
4.17
4.54
4.84
4.27
5.42
5.56
5.01
Average
Continuous
Monitor
Reading
(ppm)
307
300
250
325
320
290
390
395
340
Adjusted0
S0? Emission
Rate
(Ib/ton H2S04
per ppm)
0.01475
0.01541
0.01668
0.01398
0.01512
0.01473
0.01390
0.01407
0.01473
,,_, 'b/ton HoSO,
SCFM = standard cubic feet per minute
a EPA Reference Method No. 8
Average of two simultaneous tests
c ppm as read from the continuous sulfur dioxide monitor
ppm
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Table 2. Performance of the Sulfur Dioxide Continuous Monitor.
en
Mean
Difference
1.
2.
3.
4.
5.
6.
7.
Parameter
Accuracy Train "A"
Accuracy Train "B"
Calibration Error (45
(245
(446
Zero Drift (2 hours)
Zero Drift (24 hours)
Calibration Drift (2
Calibration Drift (24
Response Time
(ppm)
ppm)
ppm)
ppm)
hrs)
hrs)
-19.
-28.
- 3.
-22.
2.
- 0.
- 4.
- 0.
- 6.
NA
2
3
2
5
5
4
0
9
0
95%
Confidence
Interval
(ppm)
23.
22.
6.
7.
8.
5.
—
16.
—
NA
7
7
0
7
4
0
4
12.
14.
20.
12.
2.
2.
6.
1.7
Actual
Performance
5%
5%
4%
3%
4%
0%
4%
of RMV
of RMV
(of each cali-
bration gas
(mixture value
of ES
—
of ES
--
minutes (max)
Proposed
Federal EPA
Performance
Specifications
<20% of
<20% of
fof
RMV
RMV
each cali-
< 5%-
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the major portions of the applicable Federal Register, are contained
in Appendix A.
As shown, the sulfur dioxide monitor performed within the EPA guidelines
for the majority of categories. Of major importance, the relative
accuracy of the instrument was well within the performance specifications.
The mid-range and low-range calibration error and 2-hour calibration
drift did not meet the EPA guidelines. Sufficient data was not avail-
able from the interim report to evaluate 24-hour zero and calibration
drift of the instrument. The available data do indicate the analyzer
system may have some inherent problems associated with it.
Although the accuracy of the monitor is more than adequate, the high
values for calibration error at the low and mid-ranges indicate a
possible scale problem. Thus, if plant S02 output dropped to these
lower concentration levels, the accuracy of the instrument might de-
crease. Further, the 24-hour zero and calibration drift could not
be quantified from the available data, but should be determined in
order to properly schedule routine calibration requirements of the instrument.
2.2 LONG-TERM PERFORMANCE AND MAINTENANCE OF THE CONTINUOUS MONITORING SYSTEM
The DuPont 460 continuous S02 monitoring system has proven to be an
adequate system,as was borne out by the one-week operational testing
and the 6-month monitoring period. Results of the one week operational
testing period are presented in the First Interim Report under this
contract, and also in this report, but in different terms. The results
are favorable and show the DuPont system performs within most of the
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guidelines prescribed by the EPA. The system performed exceptionally
during the 6-month monitoring period. The DuPont analyzer proved to
be an accurate, reliable instrument, with low maintenance requirements
during this time.
Normal maintenance performed for the monitoring system consisted of:
1) Daily calibration by manual injection of standard gases.
2) Cleaning of probe filter.
3) Routine replacement of spent system components.
f-
Daily calibrations normally involved injection of a zero gas into the
analyzer system followed by a calibration gas of 250 ppm. These daily
operations were sufficient to minimize the effects of drift of the in-
strument, which usually occurred 16 to 18 hours after calibration.
Thus, less than daily calibration of the DuPont system may be insuf-
ficient to maintain proper instrument performance.
The monitoring system probe is equipped with a screen filter to remove
large particulate matter before it enters the sample line. During
the 6-month study period, this filter plugged about once a week, causing
a reduction in flow rate to the analyzer. This would in turn necessitate
switching to a second probe, while the filter was being cleaned, in
order to avoid a lengthy interruption of monitoring. This second probe
was not equipped with a particulate filter, but the instrument operated
normally while sampling with the secondary line. This indicates the
filter may be unnecessary for short periods of time; however, over
longer periods, entrainment of sulfuric acid mist in the sampling line,
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due to the absence of a probe filter, may cause major problems in ana-
lyzer operation. The probe filter idea should probably be retained,
but a more practical filter should be employed to remove particulate
and ^564 mist from the sample gases.
Overall, the DuPont 460 continuous S02 monitoring system displayed ade-
quate performance characteristics, has a high degree of accuracy and
reliability, required a minimum amount of maintenance, and is easily
operated. The principal improvement that could be made in the present
monitoring system, besides those mentioned above, would be in providing
an automatic calibration system wherein no manual operations need be
performed, except for the turning of a switch. A system of this nature
can easily be devised with the use of a valve-timing system. The imple-
mentation of an automatic calibration system would free operator personnel
for other duties, and be more practical for performing calibrations on
a daily, routine basis.
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3.0 PROCESS OPERATION
Plant shutdowns and process upsets occur frequently at sulfuric acid
plants and are normally due to equipment failure, breakdown or normal
maintenance of the plant. MCC's sulfuric acid plant No. 2 recorded
frequent plant down times during the 6-month continuous monitoring
period. SOp emissions exceeding 1000 ppm were recorded a total of
eight times during the study period. Six of these occurrences were
during periods of plant start-up, the other two being associated with
plant upsets. Since the range of the DuPont analyzer and of the strip
chart recorder were both set at 1000 ppm, no visual output greater than
this concentration could be obtained. However, electrical output of
the analyzer was recorded on the Westinghouse magnetic tape. This data
indicated the highest 15-minute average S02 concentration during the
study period to be approximately 1500 ppm. The reliability of the DuPont
instrument is unknown for "off-scale" readings, therefore, it is ques-
tionable whether or not the readings over 1000 ppm are accurate. The
S02 analyzer displayed no noticeable effects of going off-scale.
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4.0 OPERATIONAL COSTS
Table 3 lists the level of effort and costs associated with the complete
continuous monitoring project. This table assumes that a consultant
obtains, installs, and operates the monitoring system under a turn-key
contract. The specifics of each category are listed under the "comments"
section. Note that under the given contractor situation, the source
plant personnel retain an active role in operating and maintaining the
monitoring system.
Cost estimates based on the source plant obtaining, installing, and
operating the continuous monitoring system were not available at the
time of this report. The estimates will hopefully be forthcoming
shortly after this report is submitted. However, the man-hours asso-
ciated with the monitoring task would probably not be significantly
different than those listed in the attached table, excluding travel
time. Dollar amounts might be quite different.
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TABLE 3.
ro
i
Source H?SO/t Plant, Miss. Chem. Corp.
lnstrument(5) DuPont 406 SO, Analyzer Attachment #1~COHTINUOUS MONITORING
Cost and Level of Effort Based Upon Procurement, Installation, and Operation by a Service Organization (e.g., an Engineering Consultant Firm)
1. Site Selection and
Preparation^
2. Instrument Selection
and Purchase
a. Monitoring Instrument
b. Data Recorder6
3. System Design
a. Monitor—Recorder
Interface
b. Calibration Systeitr
c. Enclosures (Shelters)
d. Other
4. Installation, Setup,
and Calibration
5. Check-out and Certification
(Manual Testing & Report)
6. Maintenance (one year)
7. Data Handling, Reduction
and Report Preparation
(one year)
8. Direct Administrative Cost
Level of Effort
Man-Hours Total Cost
24
NA
24
65Q.
NA
550
10
NA
NA
250
290
320
' 200
75
270
NA
NA
3750
3000
3100
3000
1150
Rental
Cost or
Service Charqe
(per year)
NA
$5300
(Semi-Automatic)
$1750
Travel
Number of
Round Trips
1
NA
NA
NA
Other Comments
(Gainesville, Fla. to Pasragonla,
(Performed by Source Personnel
(Instrument installed prior to EPA
(evaluations
(Westinghouse Adviser Tape Recorder
§onitor & Probe Supplied by DuPont
ecorder supplied by Westinghouse
ample Line supplied by Samuel Norse Co.
(Someone in.iects calibration gases daily
(Included in original purchase
NA
(Gainesville, Fla. to Pascagoula. Miss.
/ ii M ii n ii
(Personnel at plant maintain Instrument
( Westinghouse evaluates tapes on computer
NA
Assuming tue consultant obtains, installs and operates the monitoring system, under a turn-key contract.
Include all fees and overhead; assume one year on-line operation.
clndicate origin and destination under "Comment"; e.g., plant to vendor.
Additional costs not included in items 1 through 7.
eSpecify type.
Specify whether manual or automatic.
^Assu:ne scaffolding and other facilities for manual testing already exist.
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APPENDIX A
PROCEDURES FOR DETERMINING ACTUAL PERFORMANCE
OF THE MONITORING SYSTEM
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Procedure for Determining Mean Values
and 95% Confidence Intervals
MEAN VALUE
X = i=l
Where X = Mean Value
X.j = Individual Values
n = Number of Data Points
z = Sum of the Individual Values
95% CONFIDENCE INTERVAL
CI95 = ,/n (= *i2) - (l X.)2
Where CIg5 = 95% Confidence Level
X.,- = Individual Values
T} = Number of Data Points
z = Sum of the Individual Values
t Q7t. = t, a for n samples from a table of
• •/ / o i ~"y t
percentages of the "t" distribution
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32861
PROPOSED RULE*
. Date of Test _.
Span Filter
Analyzer Span Setting
1
Upscale 2
3
_ 1 Opacity
2 Opacity
seconds
seconds
seconds .
Downs cale
1
2
3
seconds
seconds
seconds
Average response
seconds
Figure 1-2. Response Tire Test
Zero Setting.
Sp*n Setting,
,(See paragraph 6.2.1)
Cite Zero Reading
end (Before cleaning
line end adjustment)
Span Reading Calibration
Zero Drift (After cleaning and zero adjustment Drift
(iZero) but before span Adjustment) (iSpan)
Zero Drift • [Mean Zero Drift* + Cl (Zero)
« Emission Standard] x TOO » .
Calibration Drift - [Kean Span Drift* + CI (Span).
» Enlsslon Standard] x TOO ».
Absolute value
Figure 1-3. Zero and Calibration Crlft Test
PERFORMANCE SPECIFICATION S—PERFORMANCE
SPECIFICATIONS AND SPrciPICATION TTST PRO-
CEDURES FOB MONITORS Or SO, AND NO, FROM
STATIONARY SOURCES
1. Principle and Applicability.
1.1 Principle. Oases are continuously sam-
pled In the stock emissions und analyzed for
either sulfur dioxide or oxides of nitrogen
by a continuously operating emission meas-
urement system. Sampling may Include either
the extractive or non-extractive (In aitu) ap-
proach.
1.2 Applicability. This method Is appli-
cable to the Instrument systems specified by
subparts for continuously monitoring oxides
of nitrogen and sulfur dioxide emissions.
Specifications for continuous measurement of
nitrogen oxides or sulfur dioxide nro given
In terms of performance specifications. Test
procedures are given to determine the capa-
bility of the measurement systems to conform
to the performance speculations prior to
approving the systems Installed by an atlccted
faculty.
2. Apparatus.
2.1 Calibration Oas Mixture. Mixture of a
known concentration of pollutant gas in
oxygen-free nitrogen. Nominal concentrations
of SO percent and 00 percent of *paa are
recommended. The 00 percent pas mixture Is
to be used to set and to check the span and
Is referred to as the span gas. The gas mix-
tures shall be analysed by the Applicable
reference method (See 5.1.1) within 2 weex.s
prior to use. or demonstrated to bo accurate
and stable by an alternate method subject
to approval of the Administrator.
2.2 Zero Oas. A gas containing less than 1
ppm of the pollutant gas.
2.3 Equipment for rr.exsurerr.ent of the
pollutant gas concentration using the ref-
erence method specified In the applicable
standard.
2.4 Chart necorder. Analog chart recorder,
Input voltage range compatible with analyzer
system output.
2.5 Continuous measurement system lor
SO, or XOi pollutants as applicable. -
3. Definition*.
3.1 Measurement System, The total equip-
ment required for the determination of a
pollutant gas concentration In a given source
effluent. The system consists ol three major
subsystems:
• 3.1.1 Sampling Interface — That portion of
the measurement system that performs one
or more of the following operations: delinea-
tion, acquisition, transportation, and con-
ditioning of a sample of the source eQuent
or protection of the analyzer from the hostile
Aspects of the sample or source environment.
3.1.2 Analyzer — That portion of the meas-
urement system which senses the pollutant
gas and generates a signal output that Is a
Junction ol the pollutant concentration.
3.13 Data Recorder— That portion of the
measurement system that provides a per-
manent record of the output signal In terms
of concentration units.
32 Span. The value of pollutant concen-
tration at which the measurement system Is
set to produce the maximum data display
output. For the purposes of this method,
the span shall be set at a sulfur dioxide or
nitrogen dioxide concentration equivalent to
1.5 times the relevant emission standard.
3.3 Accuracy (Relative). The degree of cor-
rectness with which the measurement system
yields the value of gas concentration of a
sample relative to the value given by a de-
fined reference method. This accuracy Is ex-
pressed In terms of error, which Is the dif-
ference between the paired concentration
measurements expressed as a percentage of
the mean reference value.
3.4 Calibration Error. The difference, be-
tween the pollutant concentration Indicated
by the measurement system and the known
concentration of the test gas mixture.
3.5 Zero Drift. The change In measurement
system output over a stated period of time of
normal continuous operation when the pol-
lutant concentration at the time for the
measurements Is zero.
3.6 Calibration Drift. The chanse In meas-
urement system output over a stated period
time of normal continuous operation when
the pollutant concentration at the time of
the measurements Is the^ame known upscale
value.
3.7. Response Tl.T.e. The time Interval from
a step change In pollutant concentration at
the Input to the measurement system to the
.time at which 95 percent of the correspond-
ing Qr.al value Is reached as displayed on the
measurement system data presentation de-
vice.
3.8 Operational Period. A minimum period
of time over which a measurement system
|j expected to operate within certain per-
formance specifications without unscheduled
maintenance, repair or adjustment.
4. Measurement System Performance
A measurement system must meet the per-
formance specifications In Tablo 2-1 to be
considered acceptable under this method.
HDERAl REGISTER. VOL 39, NO. 177—WEDNESDAY. SEPTEMBER 11, 1974
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PROPOSED RULES
32805
TABU 2-1.—PinronMANci SPZCOICATIOHS
' . Parameter gpedflcatlon
1. Accuracy* ..." . ......— :£20% of reference mean Talue.
3. Calibration error* — «£«% of each (60%. 80%) calibration gaa
• mixture, value.
3. Zero drift (2 hours) • ^£2% of emission standard,
4. Zero drift (21-hour)* —— —* 7c of emission standard.
6. Calibration drift (2 hours)* ._— £"2% of emission standard.
6. Calibration drift (24-hour)* ??67c of emission standard.
7. Response time 16 minutes maximum.
B. Operational period... 168 Lours minimum,
•Expressed as turn of absolute mean value plus 95 percent confidence Interval of a series
of tests.
6.12 The 6} percent confidence Interval
(two tided) is calculated according to equa-
tion 3-2.
6. Performance Specification Te.it Pro-
cedures. Trie following test procedures Bhnll
be used to determine coiilormance with the
requirements of paragraph 4:
6.1 Calibration test.
5.1.1 Analyze each calibration pas mixture
(50';t, SO1;}) using reference methods C for
sulfur dioxide and 7 for oxides of nitrogen.
and record the results on the example sheet
shown in Figure 2-1. This step may be omit-
ted for non-extractive monitors where dy-
namic calibration gas mixtures are not xiscd
(See 5.1.2).
6.1.2 Set tip and calibrate the complete
measurement system according to the man-
ufacturer's written Instructions. This may
be accomplished either In the laboratory or
' In the field. Make a scries of five non-contec-
utlve readings with span gas mixtures alter-
nately at each concentration (e.g., 50','. W.i,
6071. 90%, 50',c, etc.). For non-extractive
measurement systems, this test may be per-
formed using procedures and two or more
calibration gas concentrations differing by
a factor of two or more, certified by the man-
ufacturer. Convert the measurement system
output readings to ppm and record the re-
cults on the example sheet shown In Figure
2-2.
62 Field Test for Accuracy (Relative). Zero
Drift. Calibration, and Drift—Install and op-
erate the measurement system in accordance
with the manufacturer's written instructions
and drawings as fo)lo\vs:
6.2.1 Conditioning Period—Offset the zero
setting at least 10 percent of span so tbat
negative zero drift can be quantified. Operate
the system for au Initial 163-hour condition-
Ing period In a normal operational manner.
622 Operational Test Period—Operate
the. system for an additional 168-hour
period! The system shall monitor the source
effluent at all times except when being
eeroed, calibrated, or backpurged. For meas-
urement systems employing extractive
campling. It Is recommended that the meas-
urement system and the- probe tips be
placed adjacent to each other in the duct.
Record the reference methods test data and
measurement system concentrations on the
example dato sheet shown In Figure 2-3 for
the tests given as follows:
• 55.2.1 NO, Monitoring Systems. Make
twenty seven NO, concentration measure-
ments using the applicable reference
method. No more than three measurements
shall be performed In any one hour, and
any set of three measurements shall be
performed concurrently or within a 3-
mlnute Interval and the results averaged.
62.2.2 SO. Monitoring Systems. Make
nine SO. concentration measurements using
the applicable reference method. No more
than one measurement shall be performed
In nny one hour.
6.2.3 Field Test for Zero Drift and Cali-
bration Drill. Determine the values given by
rero nnd span (."as pollutant concentrations
at 2-hour Intervals until 15 sets of data are
obtained. Alternatively, for non-extrnctlve
. measurement systems, determine the values
given by an electrically or mechanically pro-
duced zero condition and by Inserting a
certified calibration gas concentration
equivalent to not less than 300 ppm Into the
measurement system. Record these readings
on the example Eheet shown in Figure 2—4.
These 2-hour periods need not be consecu-
tive but may cot overlap. The zero and span
determinations to be made under this para-
graph may be made concurrent with the
tests under 5.2.2. Zero and calibration cor-
rections and adjustments are allowed only
at 24-hour Intervals or at such shorter In-
tervals as the manufacturer's written In-
structions specify. Automatic corrections
made by the measurement system without
operator intervention or Initiation are al-
lowable at any time. During the entire 168-
hour operational test period, record the
values given by zero and span gas pollutant
concentrations before and after adjustment
at 24-hour intervals In the example sheet
shown in Figure 2-5.
6.3 Field Test for Response Time.
5.31 This test shall be accomplished using
the entire measurement system as Installed,
including sample transport lines U used,
Flow rates, line diameters, pumping rates,
pressures (do not allow the pressurized cali-
bration gas to change the normal operating
pressure in the sample line), etc., shall bo
at the nominal values for normal operation
as specified in the manufacturer's written
instructions. If the analyzer is used to
sample more than one pollutant source
(stack), this test shall be repeated for each
sampling point.
5.3.2 Introduce zero gas into the measure-
ment system sampling Interface or as close
to the sampling interface as possible. When
the system output reading has stabilized.
. switch quickly to a kno-.vn concentration of
pollutant gas at 70 to 90 percent of span.
Record the time from concentration switch-
ing to final stable response. After the sys-
tem response has stabilized at the upper
level, switch quickly to a zero concentration
of pollutant cos. Record the time from con-
centration switching to final stable response.
Alternatively, for nonextractive monitors,
the highest available calibration pas con-
centration shall be switched into and out
of the sample path and response times
recorded. Perform this test sequence three
(3) times. For each test record the results
on the example sheet shown in Figure 2-6.
6. Calculation}, Data Analysis and Report-
ing.
6.1 Procedure for determination of mean
values and confidence intervals.
C.I.I The mean value of a data set Is cal-
culated according to equation 2-1.
' . " <•>» Equation 2-1
where:
x, = Individual values.
l' = sum of the individual values,
x = mean valvie. and
n = number of data points.
f»Vn— 1
Equation 2-2
where:
IX. = Bum of all data polnta,
='l— o/2. and
W=95 percent confidence Interval esti-
mate of the average mean value,
VAXUTB ron '.876
2 ....... r.. ......... - ............. 12.706
3 ................. - ............... 4.303
4 -. ...... . ........................ 3.182
6 .................... - ............ 2.776
6 _________________________________ 2.571
7 ............ - ................... . 2.447
8 .......... ______ ................. 2.365
9 ................................. 2.30S
10 - ............ - .......... _ ........ 2262
11 .................. _____ .......... 2.228
12 _____ . ............ - ....... - ...... 2.201
13 ........... ------------ .......... 2.179
14 _____________________ ............ 2.160
15 ........ . ........... - ............ 2.145
16 ........................ --- ...... 2.131
The values In this table are already cor-
rected for n-1 degrees of freedom. Use n equal
to the number of samples as data points.
62 Data Analysis and Reporting.
62.1 Accuracy (Relative) For each of the
nine reference method testing periods, de-
termine the average pollutant concentration
reported by the continuous measurement
system. These average concentrations shall be
determined from the measurement system
data recorded under 522 by integrating the
pollutant concentrations over each of the
time Intervals concurrent with each refer-
ence method test, then dividing -by the
cumulative time of each applicable reference
method testing period. Before proceeding to
the next step, determine the bases (wet or
dry) of the measurement system data and
reference method test data concentrations.
If the bases are not consistent, then a mois-
ture correction shall be applied to either the
reference method concentrations or the
measurement system concentrations as Is
appropriate. The correction factor shall be
determined by moisture tests concurrent
with the reference method testing periods.
The moisture test method and the correc-
tion procedure employed shall be reported.
For each of the nine test runs, subtract the
respective reference method test concentra-
tions (use average of each set of 3 measure-
ments for NO,) from the continuous moni-
toring system average concentrations. Using
these data, compute the mean difference and
the 95 percent confidence Interval using
equations 2-1 and 2-2. Accuracy is reported
as the sum of the absolute value of the mean
difference and the 95 percent confidence in-
terval expressed as a percentage of the mean
reference method value. Use the example
sheet shown in Figure 2-3.
62.2 Calibration Error — Using the data
from paragraph 5.1. subtract the measured
pollutant concentration determined under
paragraph 6.1.1 (Flfure 3-1) from the value
shown by the measurement system for each
of the 5 readings at each concentration meas-
ured under 6.1.2 (Figure 2-2). Calculate the
mean of these difference values and the 95
percent confidence Intervals according to
equations 2-1 and 2-2. The calibrntion error
Is reported as the sum of the absolute value
of the mean difference nnd the PS percent
confidence interval as a percentage of each
respective calibration pas concentration. Use
example sheet shown In Figure 2-2.
62.3 Zero Drift (2-hour) — Using the zero
concentration values measured each 2 hours
FEDERAl REGISTER, VOL. 39. NO. 177—WEDNESDAY, SEPTEMBER 11. 1974
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328GG
PROPOSED RULES
during th» Geld if at. calculate the dlfTerenccs
between coniemttvc 2-hovir rcucllngs express-
ed In ppm. Calculate the niton dlMercnce
And the confidence Interval using equation*
9-1 and 3-2. Report the yero drift M tli»
Bum of the absolute mean value and the
confidence Interval as a percentage of the
emission standard. Use example sheet shown
In Klguro 2-4.
6.2.4 Zero Drift (24-hour)—Using the zero
concentration values measured every 24
hours during the field tost, calculate the dif-
ferences between the rx?ro point after zero
adjustment and the zero \alue 24 hours later
Just prior to zero adjustment. Calculate tho
mean value of thcso points and Hie confi-
dence Interval using equations 2-1 and 2-2.
Report the zero drill (tho sum of the abso-
lute mean and confluence Interval) as a per-
centage of the emission standard. Use exam-
ple sheet shown In Figure 2-S.
6J2.5 Calibration Drift (2-hour)—Using
the calibration values obtained at 2-hour In-
tervals during the field test, calculate the
differences between consecutive 2-hour read-
Ings expressed as ppm- These values should
be corrected for the corresponding zero drift
during that 2-hour period. Calculate the
mean and confidence interval of these cor-
rected difference values us In; equations 2-1
and 2-2. Do not use the differences between,
non-consecutive readings. Report the cali-
bration drift as the sum of the absolute mean
end confidence interval as a percentage of
the emission standard. Use the example sheet
shown In Figure 2-4.
6.2.6 Calibration Drift (24-hour)—Using
the calibration values measured every 24
hours during the field test, calculate the
differences between the calibration concen-
tration reading after zero and calibration ad-
justment and the calibration concentration
reading 24 hours later after zero adjustment
but before calibration adjustment. Calculate
the mean value of these differences and the
confidence Interval using equations 2—1 and
2-3. Report the sum of the absolute mean
and confidence Interval as a percentage of
the emission standard. Use the example sheet
shown In Figure 2-5.
6.2.7 Response Time—Using the charts
from paragraph 5.3, calculate the time Inter-
val from concentration switching to 95 per-
cent to the final stable value for all upscale
and downscale tests. Report the mean of the
three upscale test times and the mean of
the three downscale test times. The two av-
erage times should not differ by more than
15 percent of .the slower time. Report the
Blower tune as the system response time.
Use the exafnple ihret shown In Figure 3-8.
8.3.8 Operational Test Period—During the
168-hour performance and operational test
period, the measurement nystem shall not
require any corrective maintenance or repair
or replacement or adjustment other than
that clearly specified as required In the op-
eration and maintenance manuals aa routine
and expected during a 1-week period. If the
measurement nystcm operates within the
specified performance parameters and docs
not require corrective maintenance, repair.
replacement or adjustment other than as
specified above durl.i" the ICO-hour test pe-
riod, the operational period will be success-
fully concluded. Failure of the measurement
to meet this requirement thall call for a
repetition of tho ICB-hour test period. Por-
tions of tho test which were satisfactorily
completed need not be repeated. Failure to
meet any performance specifications shall
call for a repetition of the 1-wcek perform-
ance test period and that portion of the
testing which U related to the failed speci-
fication. All maintenance and adjustments
required shall be recorded. Output readings
ehnll be recorded before and After all adjust-
ments.
7. Re/erentei.
7.1 Monitoring Instrumentation for the
Measurement of St/J/ur Die-ride in Station-
ary Source Emissions, Environmental Protec-
tion A;cncy. Research Triangle Pork, N.C.,
February 1073.
7.2. Instrumentation /or the Determina-
tion of Xitro*jen Oiidei Content o/ Station-
ary Source Emissions. Environmental Protec-
tion Agency. Research Triangle Park. N.C,
Volume 1. APTD-0047. October 1971; Volume
2, APTD-0042. January 1972.
7.3 Experimental Statistics. Department of
Corrunerce. Handbook 91. 19C3, p. 3-31. par-
agraphs 3-3.1.4.
7.4 Performance Specifications for Station-
ary-Source Monitoring Systems for Case*
and Visible Emissions. Environment*! Protec-
tion Agency, Research Triangle Park, N.C.
EPA-650/2-74-013. January 1974.
Reference Kethod Used
Date
K1d-Ranae'Cal1brat1on Gas "Mixture1
Sample 1
Sample 2
Sample 3
Average
ppn
ppm
ppn
ppm
man-Ranee (span) CaHEratlftfi GaS Hfxture
Sample 1 PPB • ' -•• '
Sample 2 ppa
Sample 3 j>pn
Average„ ppn
Figure 2-1. Analysis of Calibration Gas Mixtures
FEDElAl REGISTES, VOL 39, NO, 177—WEDNESDAY. SEPTlMBEg II, 1774
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