Determining the Accuracy of SO 3 /H 2 SO 4 Measurements: Development of a Field Spiking Procedure...

Determining the Accuracy of SO3/H2SO4 Measurements:

Development of aField Spiking Procedure

Presented at Electric Utilities Environmental Conference (EUEC)Phoenix, AZ

February 3rd, 2010Presented byDaniel Roesler

Principal Investigator and Field EngineerClean Air Engineering, Inc.

Determining the Accuracy of SO3/H2SO4 Measurements: Development of a Field Spiking Procedure

Copyright 2010 Clean Air Engineering, Inc. EUEC 2010

Why Spike?

• SO3/H2SO4 difficult to measure

• SO3/H2SO4 validation sources don’t exist

• Measurement Techniques– Based on theory– Have not been validated– May contain biases for

common situations

SO3H2SO4 (vapor) H2SO4 (mist)

Dale A. Lundgren, Paul Urone and Thomas Gundersn, "A Stack Gas Sulfate Aerosol Measurement Problem", In Workshop Proceedings on Primary Sulfate Emissions from Combustion Sources, Volume 1, EPA-600/9-78-02tia, (August 1978), pp. 161-178



Measurement Techniques

Manual Methods, Including Controlled Condensation

(8, 8A, CleanAir 8B, etc.)

Continuous Methods (TDL, FTIR, etc.)



Dynamic Spiking Concept

• Dual controlled condensation sampling trains:– One Spiked– One Unspiked

• Generate SO3 on demand using platinum catalyst

• Inject a known amount of SO3 into spiked train probe tip

• Compare spiked train recovery to unspiked train recovery• Determine method bias based on spike recovery



SO3 Generation

• SO3 generation via platinum catalyst• Catalyst contained inside probe• SO3 generated just prior to injection



SO3 Generation Testing



SO3 Generation Conditions



Spiking Probe



FTIR Detection of SO3

• SO3/H2SO4 reacted with FTIR windows, creating buildup of interference that overshadowed SO2 and SO3 peaks

• Only relative accuracy and stability measurements

• Lacked reference spectra for low concentrations of SO3



Spike Recovery



Conclusion

Yes!We can reliably generate a known amount

of SO3 spike within a ±20% range.

Yes!We can capture that SO3 spike using

controlled condensation in a field setting.



What’s Next

• Make dynamic spiking available for SO3/H2SO4 testing immediately (patent pending)

• Further develop alternative catalyst– Shrink the ±20% recovery range to ±5%– Remove the need for seasoning and pre-ramping

• Create low level SO3 reference spectra for FTIR

• Validate other SO3/H2SO4 measurement techniques using SO3 generation and spiking system, such as new ASTM SO3/H2SO4 method



Questions?

Special Thanks

This presentation will be available online athttp://www.cleanair.com/SO3

Determining the Accuracy of SO 3 /H 2 SO 4 Measurements: Development of a Field Spiking Procedure...

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