In this recent conference presentation, TRC's Tom Dunder compared various emissions testing strategies to provide the most accurate and useful data to coal-fired facilities undertaking dry sorbent injection studies.

1. Use of Advanced StackTesting
Technologies to Perform DSI
Evaluation Studies
Thomas A. Dunder, Ph.D.
Principal Scientist - FTIR Emissions Testing
TRC Environmental Corporation
EUEC Paper C5 -1, February 4, 2014
Phoenix, Arizona
1

2. The Challenge – Accurate, Real-
Time, Multi-Location Data
2
 Dry sorbent injection (DSI) is an option for utilities to
control SO2, acid gases (HCl, HF) and mercury (Hg)
emissions. There are numerous sorbent options
specifically for SO2/acid gases or Hg control
 DSI must be evaluated at each facility to determine
optimal sorbents, injection rate, and injection points.
 DSI studies require accurate and sensitive real-time
emissions/removal efficiency data to identify the
ideal sorbent parameters. There are testing options
that vary in cost and data quality.
 Costly decisions are made based on a DSI
evaluation so quality data is critical.

3. Consideration for DSI Evaluation –
Testing Prospective
 Sorbent (Lime, SBC, Trona (Acid Gas/SO2),
PAC (Hg), newly developed sorbents)
◦ Vary in cost, effectiveness
 Injection Rate to meet MATS limits
 Injection Location
◦ Maximize gas-particle interaction
 Sorbent Particle Size – on-site mill?
 Sorbent Interaction
◦ Sorbent-Sorbent (PAC/Acid Gas Sorbents)
◦ NH3/SO3 added to gas stream
3

4. DSI Evaluation Data Requirements
 Removal efficiency for HCl, HF, SO2 and Hg
as a function of sorbent and injection rate
 Extended test periods to ensure stable
plant and sorbent equilibration conditions
 On-site data to evaluate DSI effectiveness
and modify injection rates as needed
 Mapping of removal efficiency over a
range of injection conditions to ensure MATS
compliance now and in the future
 Detailed test plan with close coordination
between plant, DSI vendor, and test team
4

5. What needs to be measured?
 Acid Gases (HCl, HF) – removal efficiency
 Mercury (elemental, oxidized, particle bound)
– removal efficiency
 Sulfur Dioxide - removal efficiency
 Particulate Matter – demonstrate no
emissions impact due to sorbent
 O2/CO2 – emission rate determination
 Fuel Analysis – F Factor for lb/MMBtu
emission rate (cannot use ppmin vs ppmout)
5

6. What are the Testing Options?
 Multiple test methods available for acid
gases, mercury, SO2
◦ “manual” methods- impinger, sorbent tube
◦ real-time instrumental technologies
 Data collection points
◦ Measure at stack only (DSI off=baseline)
◦ Measure upstream/downstream of DSI
injection for true removal efficiency
◦ Stack-only data assumes no variation in
plant emissions/DSI rates to determine
removal efficiencies. 6

7. DSI Source Testing Demonstration Options
Option Benefit Risks/Challenges
Testing at Stack Only
with Manual Sampling
(M26A, M30B) and M6C
(SO2)
Lower Cost Composite samples - no real-time,
on-site data. Sensitivity issues.
No data on source/DSI variation
No true removal efficiency data
Testing at Stack Only
using Instrumental
Methods (M320, M30A)
Real-time, on-site data Increased cost. Specialized
equipment and personnel needed.
No data on source/DSI variation
No true removal efficiency data
Upstream/Downstream
Testing using
Instrumental Methods
Real-time, on-site data
including removal
efficiency. Detect
plant/DSI variations.
Select optimal, stable
time periods
Increased cost. Specialized
equipment and personnel needed.
7

8. Testing Diagram
8
Fabric Filter
or ESP
Coal-Fired Boiler
Sorbent Injection
(Economizer
Outlet, Air Heater
Inlet or Outlet)
Inlet Sample
Stack
Sample
Hg, FTIR
Analyzers

9. Testing Options – Acid Gases
 EPA Method 320
◦ FTIR (Fourier Transform Infrared)
◦ Instrumental Test Method with real-time
data (typically 1 minute response)
◦ Multicomponent detection (coal-fired
utility: HCl, HF, CO, CO2, H2O, NO, NO2,
N2O, SO2, HBr…)
◦ High sensitivity (~50 ppb HCl detection
limit)
◦ All spectral data archived for reanalysis
9

10. TRC FTIR Lab – Paired FTIRs,
Heated Sampling System
10

11. Mercury Testing Options
 Mercury can be measured by sorbent tube
(M30B) or real-time analyzer (M30A)
 Instrumental analysis gives speciated
(elemental/oxidized Hg) and continuous, 24
hour/day data
 Sorbent tubes can be analyzed on site for
same day data
 Equipment costs higher for instrumental
analysis, manpower costs higher for
sorbent tube
11

12. Real-Time Inlet/Outlet Testing
 Simultaneous data allows determination of:
◦ Plant stability
 Conditions like load change, plant upset, and
soot blow are not appropriate to determine DSI
efficiency
◦ DSI Stability
 Variable injection rate or injection interruption
conditions not appropriate
 Allow DSI to equilibrate – can take hours
 Equilibration critical for Fabric Filters
◦ Select data from stable plant/DSI time
periods to calculate efficiency 12

13. DSI Stability – Impact on Data
Quality
13
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
0
50
100
150
200
250
300
7:05 8:11 9:18 10:24 11:30 12:36 13:42 14:49 15:55 17:01
HClppmvw
SO2ppmvw
Axis Title
SO2, HCl Inlet/Outlet Data During Sorbent Injection
SO2 Outlet SO2 Inlet HCl Outlet HCl Inlet
SO2 Inlet
SO2 Outlet
HCl Inlet
HCl Outlet
DSI Rate 1 DSI Rate 2
DSI Rate 3DSI Injection Failure

14. Plant Instability – Impact on Data
Quality
0
20000
40000
60000
80000
100000
120000
140000
0
50
100
150
200
250
300
350
400
7:12:00 AM 9:36:00 AM 12:00:00 PM 2:24:00 PM
H2O,CO2ppmvw
SO2,NOppmvw
Time
Stack Measurements - Plant Instability
SO2 NO
CO2 H2O
Steam Drum Leak Causes
Oscillating Emisions
Sorbent Off
14
Instability detected by FTIR – Control Room unaware

15. Sorbent Stabilization: Consecutive
4-Hour Test Periods
0
80
160
240
320
400
0%
20%
40%
60%
80%
100%
1 2 3 4 5 6
SO2ppmvw
%RemovalHCl,SO2
4-Hour Time Period
Consecutive 4-Hour SBC Injection Periods (2500 lb/hr)
HCl % Removal SO2 % Removal SO2 ppm In SO2 ppm Out
% HCl Removal
% SO2 Removal
SO2 Inlet ppmvw
SO2 Outlet ppmvw
15

16. Sorbent Stabilization: Consecutive
4-Hour Test Periods
0.0
0.2
0.4
0.6
0.8
1.0
0%
20%
40%
60%
80%
100%
1 2 3 4 5 6
SO2ppmvw
%RemovalHCl,SO2
4-Hour Time Period
Consecutive 4-Hour SBC Injection Periods (2500 lb/hr)
HCl % Removal SO2 % Removal HCl ppm In HCl ppm Out
% HCl Removal
% SO2 Removal
HCl Inlet ppmvw
HCl Outlet ppmvw
HCl and SO2 removal not
correlated
16

17. HCl % Removal vs. Injection Rate
-40%
-20%
0%
20%
40%
60%
80%
100%
0.0E+00
5.0E-04
1.0E-03
1.5E-03
2.0E-03
2.5E-03
0 1000 2000 3000 4000
%HClRemoval
lb/MMBtuHClEmissionRate
lb/hr Sorbent Injection Rate
HCl Emissions Versus Sorbent Injection Rate (SBC)
HCl lb/MMBtu
HCl MATS Limit
HCl % Removal
Below MATS Limit
without DSI
Limited reduction above
1600 lb/hr
17

18. SO2 % Removal vs. Injection Rate
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0 1000 2000 3000 4000
%SO2Removal
SO2lb/MMBtu
lb/hr Sorbent Injection Rate
SO2 Emissions Versus Sorbent Injection Rate
SO2 lb/MMBtu
SO2 MATS Limit
SO2 % Removal
18

19. QA Considerations for DSI
Evaluations (FTIRTesting)
 Primary focus of testing is long term,
extended measurements with minimal
downtime for QA procedures
 Generally follow EPA Method requirements
with addition of:
◦ Measure one source with both FTIRs
simultaneously to verify inter-agreement
◦ Compare Plant CEMS data with FTIR (CO2, CO,
NOx, SO2)
◦ Compare FTIR data with other methods (M5
moisture)
19

20. DSI Study QA – Comparison with
Plant CEMS
0
50
100
150
200
250
5/28/2013 14:24 6/2/2013 14:24 6/7/2013 14:24 6/12/2013 14:24 6/17/2013 14:24
ppmvwSO2
Time
Comparison of Plant CEMS, FTIR SO2 Data
M320 SO2 CEM SO2
Average % Difference = 1.7%
20

21. Practical Testing Considerations
 Extended test- continuous 24/7
◦ Instrument/Sampling System Reliability
 Sampling System Issues
◦ Long sample lines @ 350 oF
◦ Inlet sampling – high particulate
 Monitor pump vacuum, utilize blowback
 Potential inlet scrubbing due to PM in probe filter
 Data reduced daily to select stable time
periods and reduce data (wet-dry, lb/MMBtu
calculation, % removal determination) to
provide feedback to EGU and DSI vendor 21

22. Test Data Feeds Into DSI Selection
 Test firm provides daily on-site data
summaries and final data (removal
efficiency, emission rate) to EGU and DSI
vendor
 EGU and DSI vendor process data to
compare sorbents and determine optimal
injection conditions
 Convert data to NSR (normalized
stoichiometric ratio) basis to allow sorbents
to be compared
22

23. Final Data: NSR Curve of SO2
Removal with SBC vs Trona
23

24. Conclusions
 Advanced instrumental stack testing
technologies like FTIR and Mercury CEMS
provide the time resolved, speciated data
needed for DSI evaluation
 Challenge for emissions testing firms to
provide advanced technology
instrumentation and perform the data-
intensive analysis, including on-site results
24

25. 25
Thanks for your attention
Any questions?
Thomas A. Dunder, Ph.D.
919.256.6242
tdunder@trcsolutions.com
www.trcsolutioons.com