Determining the Variability of Continuous Mercury Monitors (CMMs) at Low Mercury Concentrations EUEC 2011 Phoenix, Arizona January 31 February 2, 2011 Dennis Laudal
Tekran Comments This presentation is the original except for the following. Slide 10 the probe labels were corrected Slide 15 The correct R and R 2 values are provided Other corrections for the EERC Research Report on the ICCI website can be found at http://www.tekran.com/wpcontent/uploads/2011/06/cmm-results-at-low-hg-conc.pdf
Program Partners Illinois Clean Coal Institute (ICCI) Dr. Francois Botha Electric Power Research Institute (EPRI) Mr. Charles Dene U.S. Department of Energy National Energy Technology Laboratory (DOE NETL) Mr. I. Andrew Aurelio Center for Air Toxic Metals (CATM ) Affiliates Program Mr. John Pavlish ThermoFisher Scientific Mr. Jeff Socha Tekran Instruments Mr. Karl Wilber OhioLumex Mr. Joseph Siperstein
Project Drivers U.S. Environmental Protection Agency (EPA) Maximum Achievable Control Technology (MACT) Regulations To meet regulations may require Hg control <1.0 µg/m 3. Compliance verification cannot be effected without accurate and traceable low-level Hg measurements. Hg Abatement System Control Accurate low-level Hg measurements are required to economically operate Hg reduction systems. Optimization of Coal Supply and Blending Strategies Will rely on accurate low-level Hg measurements (market acceptance of coal-fired plants may require measurement validation). Hg Abatement Research Low-level Hg measurements are required to properly assess new control technology performance.
Project Objectives The primary goal of the project is to determine the actual variability of CMMs at mercury concentrations <1.0 µg/nm 3. Determine the variability of the components of the mercuryspiking systems. Determine the zero-mercury concentration for the instruments. Based on true spiking values for Hg 0 and HgCl 2, determine the variability of the CMMs over a 4-hour time frame for three different mercury concentrations.
Project Objectives Compare the variability of carbon trap measurements using the OhioLumex and modified EPA Method 1631. Compare the variability results with and without acid gases (SO 2 and HCl) added to the flue gas. Determine the performance of the CMMs measuring low levels of mercury (<1.0 µg/nm 3 ) when firing coal.
Project Tasks Task 1 Design and build mercury-spiking systems and ensure all equipment is operating at the highest level. Task 2 Complete test plan firing natural gas (2-weeklong pilot-scale tests). Task 3 Complete test plan firing an Illinois (Knighthawk) bituminous coal.
Mercury Measurement Methods CMMs Tekran Model 3300 ThermoScientific Freedom System Sorbent trap method (EPA Method 30B), with traps to be supplied by OhioLumex Directly analyzed using the OhioLumex RA-915+ mercury analyzer with PYRO-915 attachment Analyzed by Frontier Geosciences using modified EPA Method 1631
Tekran ThermoScientific
Test Plan for Natural Gas Tests Test Condition Mercury Mercury Concentration, µg/nm 3 Blank 0 1 Hg 0 0.25 2 Hg 0 0.5 3 Hg 0 1.0 4 HgCl 2 0.25 5 HgCl 2 0.5 6 HgCl 2 1.0 7 Hg 0 and HgCl 2 0.25/0.25
Test Plan for Coal Test Pilot-Scale Test Firing a Knight Hawk Illinois Coal System Configuration: Boiler ESP Baghouse Wet FGD
Baseline Mercury Concentration Firing PTC on Natural Gas Date Time Sampled, min Hg on Trap, ng Sample 1 Sample 2 Measured Hg Conc., µg/nm 3 Hg on Trap, ng Measured Hg Conc., µg/nm 3 2/15/10 180 12.0 0.033 12.1 0.034 4/26/10 240 19.3 0.033 19.3 0.033 4/27/10 240 13.9 0.024 14.7 0.024 4/28/10 240 16.0 0.022 14.0 0.021 4/29/10 240 8.9 0.014 10.6 0.015 5/24/10 240 35.4 0.088 44.7 0.085 5/25/10 240 17.6 0.037 15.2 0.035 5/26/10 240 12.2 0.025 11.1 0.025 5/27/10 240 9.9 0.021 10.2 0.021 Ambient Air Background Hg = 12 ng/m 3 (0.012 µg/nm 3 )
Thermo Results, µg/nm 3 on a wet basis 1.2 1.1 1.0 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 Summary of Overall Results Sorbent Trap Data, µg/nm 3 on a wet basis Graph Error: Thermo R=0.863 and R 2 =0.745 Tekran R=0.995 and R 2 =0.990 R 2 = 0.863 Natural Gas - No SO 2 and HCl Natural Gas - with SO 2 and HCl Illinois Coal 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 Tekran Results, µg/nm 3 on a wet basis 1.2 1.1 1.0 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 R 2 = 0.995 Natural Gas - No SO 2 and HCl Natural Gas - with SO 2 and HCl Illinois Coal 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 Sorbent Trap Data, µg/nm 3 on a wet basis
General Observations Overall, the testing went well. The baseline mercury levels when firing natural gas were very low (at or near ambient mercury levels). Both the Tekran and Thermo CMMs worked well on natural gas with and without the addition of the acid gases. The Tekran has a lower detection limit than the Thermo system, although both were challenged during the baseline conditions (no mercury added). The quadtrain sorbent trap results for all the tests provided a high level of precision.
General Observations The calibrators used for both instruments was consistent and within 10% of the stated value. The Tekran has a lower detection limit than the Thermo system, although both were challenged during the baseline conditions (no mercury added). Although there was some variability in the mercury emissions, the mercury concentrations were consistent over the time each quadtrain sorbent trap sample was taken. When firing coal, the Tekran appeared to match the sorbent results, but the Thermo system did not perform as well as expected.
Future Testing ThermoScientific believes they have determined the problem and are planning a repeat test under Subtask 4.10. Testing to evaluate the effects of bromine addition when measuring low-level mercury concentrations. This project has the same partners except the Wyoming Clean Coal Program rather than ICCI.
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