Pilot-Plant Performance Testing to Support Development of a Dilution Extractive HCl Monitoring System Ty Smith Cemtek Group Inc. and Ken Greaves Cemtek Instruments Inc.
Background Cemtek is researching the concept of using a trace level l HCl analyzer to measure HCl on existing coal fired boiler CEMS This is proposed to be an option for sources to comply with HCl monitoring requirements in the Portland Cement MACT and Electric Utility MATS rules Conducted at the EPA s ORD facility as part of EPA s performance testing to inform decision making. 2
Many Things to Consider HCl emissions i monitoring i is a new requirement with its own challenges Multiple l technologies are available with many fundamental differences and technical issues EPA is moving towards a performance based Performance Specification that t is inclusive i of these technologies Low level regulatory emission limits present technical challenges HCl CEMS Reference Methods (RMs) Quality and availability of Reference Gas Standards Practicality of associated procedures 3
EPA Research and Support Objectives Establish data supporting finalization of PS Evaluate commercial HCl CEMS (extractive only) as per Draft PS under controlled and representative emission environments Stack gas composition HCl emission i levelsl Demonstrate suitability of candidate RMs Demonstrate status and quality of available Gas Standards Provide environment for vendors to optimize their CEMS 4
Participating HCl CEMS 4 Commercially available, il extractive ti technologies in Test Program 2 Gas Filter Correlation (GFC) 1 FTIR 1 Dilution Extractive Trace HCl analyzer Span ranges: 0 5 ppm Over span measurement capabilities ( 100 ppm) 5
PS-18 Elements and ORD Testing Focus Interference Tests Limit of Detection (LOD) Tests 7 Day Drift Linearity RATAs Dynamic Spiking 6
Test Facility ORD s Multi-Pollutant Combustion Research Facility 4M Btu/h down-fired combustor firing coal and/or NG Multiple pollution control configurations possible SCR,ESP,FF,Wet Scrubber Duct injection of gases to control emission profiles and combinations HCl, SO 2, NO x, CH 4, CO, NH 3, H 2 O, CH 2 O All CEMS and RM measurements from same basic location 7
Reference Methods Method 26A (MATS only) Paired trains Static spiking? Methods 320/321 (ASTM D6348-12 too) Looking at 3 different high resolution FTIR analyzers Focus on DLs, measurement quality and RM performance at very low HCl levels Point of reference for HCl Gas Standards 9
Testing Status Still in early stages of testing due to extended facility maintenance All HCl CEMSs and RM FTIRs installed Vendors recently returned for final optimization Testing to date has focused on: FTIR RM measurement capabilities and performance Evaluating HCl Gas Standards d Preliminary interference tests Preliminary LOD tests Reference Method performance While while firing on NG with HCl injection Target HCl stack concentrations 0.2 2 ppm Coal combustion 20-40ppm HCl produced 10
Testing Mostly proof-of-concept at this time Learning and practicing Mostly NG with HCL injection at 0.5ppm Some coals, but HCl concentrations too high Dilution CEMS HCl performed well from 0.5ppm to 38ppm Slower response time due to in-stack style dilution probe used. Experience tells us that using an out-of-stack dilution probe will greatly speed response. RM FTIR sampled from dilution panel closely matched Trace HCl analyzer 11
Interference Testing What gases and concentrations to test? How practical is performing the test? How do individual vs. combined gases compare? The dilution HCL performed well when tested for formaldehyde interference and none was seen. No interference from other gasses due to HCl specific laser used in analyzer. 12
LOD Testing How well does the approach work? The results below are very promising below 2ppm when compared to the EPA s Reference FTIR. Reference FTIR HCl CEMS 0.5 ppm Point avg 061 0.61 057 0.57 std 0.03 0.02 LOD 0.08 0.05 2 ppm Point avg 2.00 1.99 std 0.04 0.01 LOD 0.12 0.04 0.2 ppm Point avg 0.19 0.19 std 0.02 0.01 LOD 0.06 0.04 13
3 2.5 2 1.5 1 05 0.5 0 Trend Data M321/ASTM M-26A Target FTIR HCl HCl Avg HCl CEMS "A" ppm ppmv / wet ppmv / wet ppmv / wet 0.2 0.19 0.27 0.19 0.5 0.59 0.58 0.57 20 2.0 198 1.98 201 2.01 199 1.99 3 Reference FTIR HCl CEMS "A" HCl Concentration ( ppm) 14:43:21 9:00:09 9:08: 18 9:16:30 9:24:45 9:32:51 9:41:06 9:49:21 9:57:27 10:05:45 10:13:48 10:22:03 10:30:09 10:38:24 10:46:39 10:54:54 11:03:02 11:11: 15 11:18:27 11:26:42 11:34:59 11:43:03 11:51: 18 11:59:33 12:07:39 12:15:54 12:24:09 12:32: 17 12:40:30 12:48:36 12:56:51 13:05:06 13:13: 12 13:21:27 13:29:44 13:37:48 13:46:03 13:54:09 14:02:24 14:10:39 14:18:54 14:27:00 14:35: 15 Time 14
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Gas Standards Gas Standards are needed as part of PS and on-going Quality Assurance operations Conventional compressed gases (dry), evaporative (wet), and humidification of dry gases being considered NIST traceable gas standards do not yet exist (but are in the works) Reference Gas quality at low concentrations and practicality of use a focus of our efforts 16
Test Status Unfortunately the Tiger Optics HCl analyzer sample cell was contaminated when the sample inlet was disconnected while still under high vacuum. This is potentially a major issue in the field. Tiger Optics Analyzer was removed from the test and shipped back to the factory for cleaning & recalibration. This process takes several weeks. The next phase of the test will be performed on site at a coal fired facility to test the system response on existing dilution probes and sample lines. The assumption is that dilution probes will need to be replaced with new silca coated probes. The sample lines may need to be replaced with silca coated SS sample lines but on site testing will confirm or rule this out. 17
Potential Issues For compliance reasons we are concerned about supplying or recommending an analyzer that can easily be contaminated on site if the sample inlet is disconnected. Several weeks to clean, realigning and recalibrating an analyzer is unacceptable for compliance applications. Not possible to clean this in the field. Analyzer does not have the option to calibrate zero & span on site. This is done at the factory. Analyzer communications need improving. Intermittent data lost when EPA DAS polled the Tiger Optic analyzer. Tiger Optic analyzer locked up several times and had to be rebooted. 18
Future Plans Expect to be testing through end of CY13 Sourcing additional trace HCl analyzer suppliers. These are however very limited at this time. We are evaluating 2 alternate suppliers. The goal is to have an analyzer that can be cleaned and serviced on site and wont cause a facility to be out of compliance for several weeks. We also need an analyzer a that will not be contaminated when the sample inlet is disconnected. 19
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