Using the XactTM Multi-Metals CEMS 

as a Mercury Monitor on a Coal-Fired 

Power Plant: A Feasibility Study

Cooper Environmental Services 1

Krag A. Petterson, John A. 

Cooper, Troy Pittenger, Mike 

Nakinishi

Cooper Environmental 

Services, LLC

Joe Doherty, Marty Ladner; 

Pall Corporation
Executive Summary

 Review of XactTM Design and Operation

 Goals of Feasibility Study

 Results of Laboratory Phase of Study

 Field Deployment and Performance Test Results

Cooper Environmental Services 2
The XactTM Multi-Metal CEMS

 Developed by Cooper 

Environmental Services (CES)

 Developed as a Multi-Metals 

CEMS

 Based on X-ray Flourescence 

Analysis (XRF) 

 Beta –gauge type reel-to-reel tape 

drive and sampling technology

 Can measure up to 20 metals 

simultaneously including Cr, As, 

Cd, Hg, and Pb

Cooper Environmental Services 3
Cooper Environmental Services 4

XactTM-CEMS

Control 

Module

Dilution 

Module

Sampling and 

Analysis Module

Flow Module

Connect to Probe and 

Transport Line

Main Flow From Stack

60 to 800 Lpm

Sub sample onto Tape ~1 LPM
Cooper Environmental Services 5

XACTTM SAMPLING AND ANALYSIS

X-Ray Tube

Filter Tape

Aerosol Deposit

Sample Flow

Analysis Area

Filter Tape
Determination of Stack Concentration

Cooper Environmental Services 6

CONC (μg/m3)

Mass

(XRF)

VOLUME

(MFM)

=
7

XactTM CEMS

EPA Method 301 

Validated for 

Multi-Metals 

AMP EPA 

Approved

EPA Site 

Certified

~6 Years OnStack Operations 

on Hazardous 

Waste Incinerator

May 2007 – EPA Clean Air 

Excellence Award
Key Goals of Feasibility Study

 Demonstrate Xact Operation on a Coal Fired Power 

Plant

 Can the Xact Meet the Mercury Monitoring (PS-12A) 

Requirements for Initial Certification Specified by the 

Clean Air Mercury Rule (CAMR)?

Cooper Environmental Services 8
PS-12A Initial Certification 

Requirements (2007) Current PS 12A 

Requirements Are In Red

Test Required 

Frequency

Required 

Standards

Passing Criteria

7- Day 

Calibration 

Check

1 x per day 

for seven 

days

• Zero

• Upscale

5% of Hg Span Value

-ORLess than 1 g/m3 difference

Linearity 

Check

Once Hg Standard at

Low, Mid and 

High Span Values

10% of reference value 

-ORLess than 1 g/m3 difference

3-Level 

System 

Integrity

Check

Once HgCl2 Standard

Low, Mid, High 

Span Values

5% of Span Value

Relative 

Accuracy 

Test 

(RATA)

Once • Ontario Hydro

• Method 30B 

(Sorbent Trap)

20% of Reference Method

-ORLess than 1 g/m3 difference

Cooper Environmental Services 9

Measurement 

Error

Span Value

10% of Span Value

5%
HgCl2 and Hgo Generator

 XactTM did not have a HgCl2 or Hgo Generator

 Used Commercially Available HovaCalTM

 HovaCalTM operates by evaporating a solution of HgCl2 on 

a heated surface 

 HgCl2 Solution of known concentration was metered at a 

measured flow rate into a measured air flow

 Hgois generated by chemically converting the HgCl2to 

elemental Hg (Hova Merc)

Cooper Environmental Services 10
Initial Laboratory Tests – XactTM

Calibration

 XRF Portion of the Xact Calibrated Using Thin Film 

Standards 

 These standards are typically used for calibration of XRF 

equipment for the analysis of Ambient Air Filters (EPA IO 

3.3)

 Flow Portion of the Xact Calibrated Using Reference Flow 

Meter

 Calibration for Multiple Metals Checked using 

Quantitative Aerosol Generator (QAG) 

 QAG Audit similar to that performed EPA Approved 

Alternative Monitoring Petition

Cooper Environmental Services 11

Xact Mercury Calibration is 

Completely Independent of 

the HgCl2 and Hgo Generator 

Used to Check It.
Initial Laboratory Tests With 

HovaCalTM

HgCl2 Linearity

Concentration 

Level

Nominal 

Concentration 

(mg/m3) # of Samples

Average Percent 

Difference (% of 

Span)

Pass Test 

Criteria?

Zero (DI Water) 0 6 0.40% Yes

Low 2 8 -2.37% Yes

Low Mid 4 6 -0.69% Yes

High Mid 11 6 -4.10% Yes

High 18 8 -4.17% Yes

Cooper Environmental Services 12

Also Passed Current 12A Criteria
Initial Laboratory Tests with 

HovaCalTM Elemental Hg Linearity

Concentration 

Level

Nominal 

Concentration 

(mg/m3) # of Samples

Average Percent 

Difference (% of 

Span) Pass Test Criteria?

Low 4 7 0.57% Yes

Mid 11 6 4.46% Yes

High 18 8 0.45% Yes

Cooper Environmental Services 13

Concentration Level

Nominal 

Concentration 

(mg/m3) # of Samples

Average Percent 

Difference (% of 

Reference)

Pass Test Criteria?

Low 4 7 2.66% Yes

Mid 11 6 8.69% Yes

High 18 8 0.45% Yes

With New PS12A Criteria

XactTM Met All Tested PS-12A 

Criteria During Laboratory 

Evaluation
Field Deployment

 XactTM installed at PGE’s Boardman Facility

 585 MW Facility, ESP Controls

 Lab XRF Calibration Used – Not Recalibrated in Field

 Installed and operating within

2 days

 Side by side comparison with

Thermo Mercury Freedom Unit

 Two week field deployment

 Performed initial performance 

specification including:

- 7 Day Calibration Check - Linearity Check

 - System Integrity Check - RATA – Method 30B

 

Cooper Environmental Services 14
Field Test Arrangement

Cooper Environmental Services 15
Seven Day Drift Test Results

Cooper Environmental Services 16

 Zero Drift Met on all Days – indicating little loss of Hg

 Difficulty Meeting Upscale – Problems with HovaCalTM
Field HgCl2 Linearity (System Integrity 

Check)

Cooper Environmental Services 17
Field Hgo Linearity

Cooper Environmental Services 18

Problems with HovaCal Conversion of 

HgCl2 to Hg0 Because of Low Temps in 

Converter 
Why we think there was a problem 

with HovaCalTM

 Visible Rust in Tubing Exiting HovaCalTM

 Problems Maintaining Heating – heater would frequently 

fail requiring the HovaCalTM to cool down and restart

 Were Using HovaCalTM at the Very High End of 

Recommended Emission Range

Cooper Environmental Services 19
Thermo Hg Freedom Comparison

Cooper Environmental Services 20
RATA Results

Cooper Environmental Services 21

0

1

2

3

4

5

6

7

8

9

1 0

0 1 2 3 4 5 6 7 8 9 1 0 1 1 1 2 1 3

Mercury Conc. ( g/dscm)

RATA Number

CES Xact

Method 30B

Thermo CMM

Thermo QA Period

3.53% RELATIVE 

ACCURACY FOR CES 

XACT
Conclusions

 CES Xact Can Accurately Measure Mercury in a Coal 

Fired Power Plant 

 If the XactTM had recalibrated to the mercury 

generator (HovaCalTM) as most Hg CEMS do – it 

would likely have failed the RATA

 It is feasible to use the Xact to Measure Mercury on a 

Coal Fired Power Plant

– Need a Mercury Generator Designed to Operate on XactTM

Flows

Cooper Environmental Services 22
Differences Between XactTM and AF 

Based Mercury Monitors

 XactTM Requires Longer Sampling Times (15 minutes 

versus 1 to 2 minutes)

 XRF Calibrations are very stable (1 year or more) AF 

needs to be recalibrated frequently

 XactTM is less dependant on the accuracy of the Hg 

generator

 Since XRF is Non Destructive Samples Can be Archived 

and Potentially Reanalyzed if Data needs to be validated

 XactTM could be used to monitor for other metals

– PM is a surrogate for HAP Metals

– If EPA requires PM CEMS on CFPP Xact could potentially be 

used for Hg and HAP metals

– Therefore 1 CEMS (multi-metals including Hg) instead of 2 Hg 

CEMS and PM CEMS

Cooper Environmental Services 23
QUESTIONS?

Krag Petterson

kragp@cooperenvironmental.com

Cooper Environmental Services 24