### EPA **HCl Performance Specification Draft Conference Call Summary**  **Thursday July, 21 from 1:30**

**- 2:30 EDT.**  **Call in Conference Number 1** 

**- 866** 

**- 299** 

**- 3188,**  **code is 9195415511.**

**Stakeholder Discussion Topic:**  **What are the best approaches for in the field QC/recovery checks.**

**1) Welcome** 

**– Introduction**  a) EPA plans to have stakeholder calls on various topics at a frequency of once every two weeks b) We will work from the list of issues previously sent to the stakeholder. The specific topic from the list will be announced by email prior to the meeting to allow everyone to prepare. We will try to limit discussion to the announce topic so stakeholders can choose which conference calls to attend. We plan to cover all of the topics in our original summary and may add topics that arise from our ongoing discussions with stakeholders. c) EPA will start working on a draft of the performance standard in August based in part on the information from the stakeholder calls. Over the next six weeks stakeholders (Table 1) participating in this call will start seeing draft sections of the Performance specification and is associated procedure. Comments on the drafts are welcome so we can get your input well before we have a com

plete draft. d) Our timing remains to have the first full draft for Stakeholder review by the end of the calendar year (2011).

2) Field QC Topics Discussion

- In field hot wet through the probe spiking

When area source tests were performed for cement plants, Jim Peeler

- Emissions Monitoring Inc. used Method 321Measurement of Gaseous Hydrogen Chloride Emissions At Portland Cement Kilns by Fourier Transform Infrared (FTIR) Spectroscopy. This method requires through the probe spikes, including specifications for the maximum amount of spike introduced through the probe , and the relative concentration of spike that can be used. This QC approach provides an evaluation of the measurement system since it demonstrates that you can successfully transport a known concent ration of gaseous HCl through the probe and filter cake into the heated instrument cell . For cement kiln HCl measurement, the filtered particulate matter is comprised solids that react with HCl. Through the probe spiking provides an assessment of both th e sampling/analysis system and it tests the mathematical algorithms used in some equipment to correct for interferences in the sample matrix.

a) The spike is limited to a maximum of 10% of the sample gas stream. The concentration target for through the probe spiking is the approximate concentration of the gas stream or 5 ppm is the gas tested is less than 5 ppmv. For example, spiking a gas stream of 5 ppm involves using a certified gas at 50 ppmv HCl which is diluted 10/1 resulting in the addition of a sp ike of 5 ppm in addition to the stack gas HCl . The measured concentration of native plus spike is approximately double the concentration of the native HCl. In this approach the spike gas dilutes the native concentration by approximately 10%. b) The sample gas flow rate and the spike gas flow rate must be measured very accurately or the tester can inject a known concentration of tracer such as SF 6 to determine the exact dilution.c) The calibration gas standard is also delivered directly to the measurement devi ce to determine

response of the standard gas without sampling system or sample matrix bias. This QC check is the relative concentration or relative indicator used to determine spike recovery. Direct instrument measurement of the spike gas provides the ex act response of the spike gas regardless of the absolute concentration of the certified gas cylinder. d) Spike recovery can be determined in different ways as described in the ASTM FTIR
measurement procedure for Stationary S ource s

. Recovery based requirements permit the measurement procedure to be performance based rather than the more restrictive performance requirements of a prescriptive procedure. i) Spike recovery can be based on the total expected response for the native plus the spike or ii) Spike recovery can be based on the incremental response resulting from the spike addition to the native concentration. e) For sources with highly variable HCl emissions there is a question of whether two analysis units are required so the instantaneous native HCl can be sep arated from the through the probe spike response. In both the ASTM procedure and Method 321, there are cautions about spiking when the process is not stable. One alternative useful for highly variable sources is calculating the average of native concentration just prior and just after the spike interval. Furthermore, if a the QC spike check fails and the tester believes the cause is temporal variation of the source, the spike can be repeated when the source is relatively constant. Since the measurements are continuous, a simple statistical test on process variability may be useful to identify when the measurements are out of control or the failure is due to process variability. f) EPA has a guideline document for monitoring non

- criteria pollutants that addre sses these issues. g) Allen Ri lling

- ABB: The spiking system through the probe identifies sampling system bias. What is the issue spiking at the analyzer once the initial performance of the system is verified. Jim Peeler: Through the probe spiking is valid for a period of time until the accumulation of material on the filter from the process biases the results. For cement kilns the filter collects calcium oxides and other material that reacts with HCl. Sulfur Oxides compete for adsorption sites on the filtered material so through the probe spiking needs to be done periodically to confirm the measurement system meets bias requirements. During measurement programs for HCl, testers are required to verify the in strument performance before and after each test run. The measurements requirement seems excessive for a continuous monitoring system but is standard for periodic measurement programs. However, periodic through the probe is necessary to determine when suff

icient material was accumulated on the filter to significantly bias the monitoring results. h) Robin Segall

- EPA : suggests that if daily calibration checks are required as system calibration versus an analyzer calibration. A daily calibration check through the filter will provide information on the bias caused by the filtered solids as opposed to an instrument only calibration check that provides information on instrument drift and span. System calibration through the filter should be done daily but there’s not enough information on cement kiln continuous monitoring to evaluate how often the analyte spike should be performed. Lime plants, downstream of limestone scrubbers and cement kilns are probably the worst case examples for needing through the probe analyte spikes. i) Jim Peeler: If daily system calibration checks are required then the job of the analyte spike technique performs is the same as the function of a RATA. That is to detect excessive samplingsystem bias and measurement interferences. Currently he does accuracy assessment on a

quarterly basis . He suggests doing initial certification including a series of through the probe spikes during a seven day certification period and then quarterly thereafter. j) Robin Segall: Question, are you proposing to substitute analyte spiking for a RATA against a reference method? Jim Peeler: Yes, thus avoiding the issue of using reference Method 321 for HCl based on FTIR to evaluate an FTIR CEM. If a facility failed the quarterly through the probe analyte spike th en there could be a requirement to do the spiking more frequently. k) Jim Peeler: Agreed that calibration checks include the entire system for regulatory programs and the requirement in this PS should be consistent wi th that practice. If a system calibration check fails, testers would immediately run an analyzer calibration check to eliminate drift or response changes as the cause of the system calibration check failure. l) Allen Rilling : shared his concern about the amount of gas required to perform system cal ibration checks through the probe. If quarterly checks verified no system bias, he asked if direct instrument calibration checks would be adequate. m) Laura Kenner: For cement kilns, quarterly through the probe QC checks seem too infrequent. Allen Rilling: Once you’ve built up a history of passed QC checks, then less frequent through the probe QC checks seem to make sense and would reduce costs for calibration gas as well as increase uptime for source monitoring. n) There was some discussion of needing to do a direct instrument and a system calibration check sequentially to ensure that changes in the calibration gas concentration did not bias the QC check. This assumes that the calibration is not stable and that issue will be discussed on a separate call. o) Robin Segall: Using HCl CEMS in a compliance mode will require performing system calibration checks on a relatively consistent basis. The starting point would probably be a daily calibration check since EPA established this frequency for our other compliance programs. p) Allen Rilling: Once you have an analyzer that demonstrates unbiased measurement for a year then you have support for performing less frequent calibration checks. He asked if it was possible to base the frequency of system calibration checks o n a past experience history for a specific monitor installation. q) Robin Segall: If we wrote such a Performance Specification , the data from an interval between a failure and the previous passed system calibration check would be invalid data. r) Jim Peeler: Appendix F invalidates data from the time a QC check or audit is failed forward and does not retroactively invalidate data because a source operator might be encourage to fail a test to invalidate data the facility did not “like”. For systems like FTIR th at measure multi

components, if the system is measuring one component correctly the instrument is probably measuring the other components that get to the analyzer correctly. That would mean a calibration check for one component would assure that the instr ument was operating correctly for all components. The most reactive component being measured might serve as a surrogate for the rest of the multi

- component measurements and that component will probably be HCl. 3) Alternatives to hot

– wet

– through the probe QC checks a) Rich Brown

– Altech: Is the performance specification we are discussing an update of the FTIR procedure or is it a general HCl monitoring performance specification? Candace Sorrell

- EPA: The performance specification will be generally applicab le to all technologies measuring HCl including all current HCl stack monitors and future technologies that serve this purpose. Altech uses Perma

- Pure nafion dryer technology at the probe location followed by dry delivery to amultigas NDIR filter based mo nitor. This system is not hot wet since the sample is dried at the

sampling probe/sampling location. Altech does not use an all heated system after the dryer. The system is an extractive system that brings dry cool sample to the analyzer. The stack gas hot (180

 C and filtered prior to the dryer. There is no issue with spiking in the hot wet zone in front of the filter. That means this sampling design would not be excluded from using a hot wet HCl performance spike. Jim Peeler: We’ve successfully performed hot, wet field spikes with HCl using the Altech system. 

### b) Laura Kenner

- Emission Monitoring Inc .: It seems that hot wet spiking should work for extractive systems. In

- situ monitoring systems may require a different approach. c) Keith Crab

- Cemtech Environmental: Cemtech offers an in

- situ tunable diode laser cross stack monitoring system . Cemtech uses a flow through cell in the optical measurement path that can be spiked with calibration gas to check instrument performance. The cell functions in a similar manner to the hot wet spike since it is an additive spike to the measurement path. The cell can be mounted on the stack or at the instrument. The flow through cell seems to be a valid test of the instrument performance that can be practically tested. Higher concentration gases appropriate to the path length would be required for flow through cell spiking. This technology lends itself to multipoint QC or calibration checks. At the end of a QC cycle the cell is flushed with nitrogen until the basel ine before spiking is reached. The cell remains in place during measurements and calibration checks. There is no practical way of doing a cross stack zero measurement insitu. Zero and span checks will be discussed in a separate stakeholder call. The temperature and pressure of the gas cell and the stack gas must be included in the calculation of gas concentration. Cemtech’s flow through cell is not heated and equilibrates to the temperature at its location. Lorentzian line shape is used in the calculation of concentration. d) Cemtech is also investigating an extractive dynamic probe TDL system that could be spiked with HCl through the probe similar to other extractive systems

**. 4)**  **Concentration of spikes** a) Jim Peeler: With emission standards approaching 3 ppm f or cement kilns there are issues because plants that include inline raw mills will cycle between mill off high concentrations and mill on low concentrations. What’s the best concentration to spike and is it reasonable to assume that if spikes at low concentrations are recovered successfully then higher spike concentrations will also be recovered successfully? Periodic testing supports this conclusion. b) Low concentration spikes are more a concern during calibration checks when 100 % gas (flooding the system with calibration gas) is being tested. Dynamic, hot wet spiking is not performed at no more than 10% of the volume of gas sampled which means the spike gas can be a higher concentration. The spike gas should not be the same gas as the calibration check standard gas. This hot wet dynamic spike is similar to quarterly cylinder gas audits used in other
programs. c) Luc Sevrette

– Gasmet: Are we talking about a representative daily check, and if so a calibration check going through the system dry would take mo re than an hour to equilibrate. He recommends a daily hot wet spike through the probe but not a daily calibration check with low level standards that must equilibrate through the system dry

. d) Allen Rilling : We typically spike at 75% of the measure emission level. The new compliance limits present additional bias opportunities since the concentration is so low that the deliverysystems may affect how accurately the HCl can be delivered to the probe. Optio ns to consider are

daily zero and span or daily through the probe spike

. e) Also to be considered is the possibility of using a tracer gas to verify the dilution ratio of the spike gas delivery system in place of relying on mass flow controllers or rotameters for flow measurements. This may be an option for multi

- component monitors but may be a issue for narrow wavelength or single component systems that only measure HCl. If the definition of tracer gas is left flexible, then manufacturers will have to solve this issue on an instrument specific basis.

**Table 1: Conference Call Attendees and Contact Information**

**Stak eholder Name**  **Affiliation Interest**  **Em ail**  **Present** Rachael Agnew EPA/OAQPS/SPPD/MPG EPA agnew.rachael@epa.gov Joe Aldina Covanta Energy Facility j aldina@covantaenergy.com Collin Boswell EPA/OAQPS/SPPD/MPG EPA boswell.collin @epa.gov Rich Brown Altech Equip Vendor Y Gary Catchatory Tyco Environmental Systems Equip Vendor Kieth Crab Cemtech Environmental Equip Vendor Y Edul Chikhliwala EcoChem Analytics Equip Vendor chikli@ecochem.biz Michael Corvese Thermofisher Equip Vendor mic hael.corvese@thermofisher.com Bob Davis AirGas Gas Vendor bob.davis@airgas.com Jason Dewees EPA/OAQPS/AQAD/MTG EPA dewees.jason@ epa.gov Frank Duckett Thermofisher Equip Vendor f rank.duckett@thermofisher.com Andy Edwards Ash Grove Cement Facility Gerri Garwood EPA/OAQPS/SPPD/MPG EPA garwood.gerri@epa.gov Fred Grunewald MKS I nstruments I

nc. Equip Vendor fred.grunewald@mksinst.com Des irea Haggard Cal P ortland Facility dhaggard@calportland.com Y Jeff Harrington Tyco Environmental Systems Equip Vendor Malik Hatar Altech Equip Vendor Mike Hayes Linde Gas Gas Vendor Andre Hegre Gas Technologies, Finland Equip Vendor Stephen Johnson Thermofishter I nc. Equip Vendor Stephen.Johnson@thermosisher.com Dan Kietzer Sick

- Maihak Equip Vendor dan.kietzer@sickmaihak.com Laura Kenner Emission Monitoring I nc. Tester lkinner@mindspring.com Y Dieter Kita Thermofisher Equip Vendor dieter.kita@thermofisher.com Bill McMaster PermaPure Equip Add

- on Y Barbara Marshick MKS I nstruments Equip Vendor Barbara_Marshik@mksinst.com Ray Merrill EPA/OAQPS/AQAD/MTG EPA merrill.raymond@epa.gov Y Barrett Parker EPA/OAQPS/SPPD/MPG EPA parker.barrett@epa.gov Ashmud Patel Ethyl Smith Automation Jim Peeler Emission Monitoring I nc. Tester jimpeeler@mindspring.com Y Allan Rilling ABB Equip Vendor allan.j.rilling@ca.abb.com Y Ralph Roberson RMB Consulting Tester Roberson@mb

- consulting.com Matthew Rutledge La farge Facility Robin Segall EPA/OAQPS/AQAD/MTG EPA segall.robin@@epa.gov Lu c Sevrette Gasmet Equip Vendor luc.sevrette@gasmet.com Ty Smith Cemtech Environmental Equip Vendor Candace Sorrell EPA/OAQPS/AQAD/MTG Regulatory Agency sorrell.candace@epa.gov Y

Martin Spartz Prism Analytical technology Tester m.spartz@pati

- air.com Bob Vantuyl Ash Grove Cement Facility bob.vantuyl@ashgrove Henry Veger CEM Specialties Equip Vendor Dave Vigowax Marantee Tile Facility Bethany White RMB Consulting Tester Y James Willis Titan America Facility jwillis@titanamerica.com Hector Ybanez, Holcim I nc. Facility hybanez@gmail.com Musa Zada Altech Equip Vendor Peter Zemek MKS I nstruments Equip vendor Peter_Zemek@mksinst.com Y Y= Higlighted attendance indicates first time participants.