The USEPA
has released an initial draft report concerning the long-term study of
several mercury continuous emissions monitoring systems (CEMS). Work was
conducted by the Midwest Research Institute at a coal fired utility boiler
burning eastern bituminous coal and equipped with SCR, an ESP and wet
scrubber.
The report
presents the results from certification and initial relative accuracy test
audit (RATA) testing of four mercury CEMS. Three CEMS were installed in
November 2004 and the fourth in February 2005. The RATA consisted of 12
paired-train runs using the Ontario Hydro method (ASTM D6784-02). Testing
was conducted under normal facility operations with the SCR bypassed.
Another RATA is planned with operation of the SCR.
EPRI was
also involved in the field studies. EPRI conducted a RATA using the paired
sorbent trap monitoring approach concurrent with EPA testing.
Initial
certification included a 7-day calibration error test, a measurement error
test, a linearity check, converter efficiency test, cycle time test and
zero/upscale drift tests. Instrument span was defined as 10 ug/m3.
The field
evaluation data are summarized in the following table. Note that results
from the Ontario Hydro method are not yet completed for the RATA evaluation.
|
Manufacturer: |
Forney/Genesis* |
Horiba/Nippon |
Tekran |
ThermoElectron |
|
Test |
Criteria |
|
|
|
|
|
7-Day Calibration Error Test |
<1 ug/m3 |
Test not completed.
0.2-0.3 ug/m3 (2 days) |
Passed.
0.1 to 0.5 ug/m3 |
Passed.
0.096 to 0.122 ug/m3 |
Passed.
0.04 to 0.09 ug/m3 |
|
Linearity |
<10% or
< 1 ug/m3
|
Test not performed. |
Test not completed.
Ran 1 cycle of low, mid and high.
Passed low; failed mid and high. |
Passed.
Met absolute difference (<1 ug/m3) at
low level and <10% at mid and high levels. |
Passed.
All levels <10%. |
|
Cycle Time |
<15 minutes |
Test not completed. |
Test not completed. |
Passed. |
Passed. |
|
Converter Efficiency |
<5% span |
Test not performed. |
Passed.
All levels: zero, mid and high. |
Passed.
All levels: zero, mid and high. |
Passed.
All levels: zero, mid and high. |
|
Measurement Error |
<5% span |
Test not performed. |
Test not completed.
Passed at zero level.
Failed at mid level. |
Passed.
All levels: zero, mid and high. |
Passed.
All levels: zero, mid and high. |
|
Zero and Upscale Drift |
<5% span |
Test not performed. |
Passed at zero and upscale.
Catalyst replaced twice during 7-day period. |
Passed at zero and upscale. |
Passed at zero and upscale. |
|
RATA
|
<20%
or <1 ug/m3for low emitters |
CEMS ug/m3
Run1:
Run2:
Run3:
Run4:
Run5:
Run6: 1.9
Run7: 1.7
Run8: 4.0
Run9: 2.3
Run10: 1.5
Run11: 1.6
Run12 2.0 |
CEMS ug/m3
Run1: 2.0
Run2: 2.0
Run3: 1.8
Run4: 1.9
Run5: 2.3
Run6: 1.8
Run7: 2.1
Run8: 1.4
Run9: 2.7
Run10: 2.5
Run11: 2.5
Run12 2.3 |
CEMS ug/m3
Run1: 2.639
Run2: 2.610
Run3: 2.335
Run4: 2.477
Run5: 2.870
Run6: 3.180
Run7: 2.791
Run8: 2.799
Run9: 2.909
Run10: 2.869
Run11: 2.910
Run12 3.317 |
CEMS ug/m3
Run1: 2.44
Run2: 2.53
Run3: 2.06
Run4: 2.10
Run5: 2.67
Run6: 2.70
Run7: 2.16
Run8: 2.15
Run9: 1.95
Run10: 1.71
Run11: 1.92
Run12 2.74 |
|
Sorbent Trap Data, ug/m3 |
Run1: 3.0
Run2: 3.4 |
|
Run1: 3.0
Run2: 3.8 |
Run1: 2.695
Run2: 3.325 |
|