POWER July 2016 - 29

ENVIRONMENTAL ISSUES
Table 2. Range of costs for purchasing and maintaining PM systems.
Source: TRC Companies Inc.
Option
Quarterly stack monitoring
Task
Using PM as a surrogate for non-Hg
metals HAPs
Testing for total non-Hg metals
HAPS or individual non-Hg metals
HAPs
Using PM as a surrogate for
non-mercury (Hg) metals hazardous
air pollutants (HAPS),
installing a PM monitor, and
using it as a continuous emission
monitor (CEMS). Use of
monitor as CEMS would require
certification (correlation curve)
by PS-12.
Annual PM monitor maintenance
Develop PS-12 correlation curve
(minimum of 15 test runs across
three specific grain loading conditions)
Fly
ash spiking to generate grain
loading conditions needed to build a
correlation curve that meets PS-12
guidelines
Annual Relative Response Audit
(RRA). The RRA is three test runs
to determine compliance with the
MATS limits and determine if the
resulting PM is still predicted accurately
by the correlation curve.
Using PM as a surrogate for
non-Hg metals HAPS, installing
a PM monitor and using
it as a continuous parameter
monitoring system (CPMS).
Use of monitor as CPMS would
require setting a source-specific
operating limit (monitor
output signal) that would not be
exceeded by the 30-day rolling
average output.
Purchase and install PM monitor
Annual PM monitor maintenance
Initial testing to determine compliance
with MATS and set the sourcespecific
operating limit
Annual testing to determine compliance
with MATS and reset the
source-specific operating limit
If source exceeds the source-specific
operating limit with the 30-day
rolling monitor output and corrective
action is needed, the source
will need to conduct testing to determine
compliance with MATS and
reset the source-specific operating
limit
plant operators to consider with respect to
demonstrating compliance with the nonmercury
metal HAP limit using PM as a
surrogate.
Most have followed periodic manual testing
or the use of a PM continuous monitor
as a PM CEMS. But the time has come to
take another look at the overlooked option of
using a PM continuous monitor in a CPMS
mode.
What's needed to get started?
To begin, the facility must determine
the PM limit from MATS. PM limits vary
based on fuel type and whether the source
is new or existing. MATS allows PM to be
measured and reported in lb/MMBtu or
lb/MWh, and the EGU should select the
July 2016 | POWER
Cost
$7K-$10K per quarter
$15K-$18K per quarter
Purchase and install PM monitor Depends on type of monitor and
installation contractor
Depends on type of monitor and
plant maintenance crew
$24K-$30K, assuming the three
specific grain loading conditions
can be easily provided
$50K-$100K, depending on how
many attempts are made at generating
the required grain loading
condition
$7K-$10K
■ Set a source-specific operating limit based
on these results.
■ Operate
and
maintain equipment to
achieve a 30-day PM CPMS average that
does not exceed the established operating
limit. (MATS allows the monitor output
signal that correlates to the highest 1-hour
CPMS output for existing units only; for
new EGUs it is the average output.)
■ Reset the source-specific operating limit
annually.
Depends on type of monitor and installation
contractor
Depends on type of monitor and
plant maintenance crew
$7K-$10K
$7K-$10K
$7K-$10K
The mechanism selected for determining
the source-specific operating limit will depend
on the results of the performance tests.
Once again, the source has choices. Under
MATS, if a PM monitor is being used as a
CPMS, setting the source-specific operating
limit is different for a new source than it is for
an existing source. For a new source, if the
performance tests indicate PM emissions are
less than 75% of the MATS limit, the sourcespecific
operating limit can be extrapolated
to equal 75% of the MATS limit. Only new
sources are eligible for this extrapolation.
If the performance test results are greater
than or equal to 75% of the MACT limit, the
average PM CPMS output value (milliamps)
will be the source-specific operating limit.
If the 30-day rolling average output of the
PM CPMS exceeds the source-specific operating
limit, the source must take corrective
actions as follows:
■ Within 48 hours of an exceedance, a visual
inspection of the air pollution control
device (APCD) must be performed. If the
inspection identifies the cause, corrective
action must be taken and the PM CPMS
must be returned to operation.
most favorable reporting option. The facility
will then need to conduct performance
testing using EPA Reference Methods to
demonstrate compliance with the MATS
PM emission limit.
The next step is to establish a source-specific
operating limit. To do this, the facility
will need to perform the following tasks:
■ Conduct a performance test.
■ Record all CPMS output values (milliamps
or other signal).
■ Determine 1-hour average CPMS output
readings (milliamps) during the performance
test. (Note: If you perform three
3-hour test runs, you generate nine 1-hour
CPMS averages.)
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■ Within 30 days of the exceedance, or at
the time of the annual performance (compliance)
tests, whichever comes first, a
PM performance test must be conducted
to demonstrate compliance with the PM
MACT limit and to reestablish the sourcespecific
operating limit.
■ The compliance demonstration and reset
of the operating limit must be implemented
within 45 days of the exceedance.
■ Additional testing is not required for any
exceedance that occurs between the initial
exceedance and the performance test triggered
by that exceedance.
Before devising a strategy for setting
source-specific operating limits make sure
you:
■ Apply the proper PM MACT limit based
on the source type.
■ Have an instrument that indicates the presence
of and changes in PM in the exhaust.
29
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POWER July 2016

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