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Advances in NOx Compliance Testing with

Portable Electrochemical Analyzers

LADCO Workshop:Emission Control and

Measurement Technology for Industrial SourcesMarch 24-25, 2009

Craig McKim, Emission Division Manager

Testo Inc. Sparta NJ 800-227-0729

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Summary

Testing and approvals - for portables States agency experiences with portables The technology – the good, the bad, and the

solutions Analyzer/technology description Data acquisition Application examples

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Last Night - State Roundtable Statement

OHIO – Identified an untapped source of NOx Reduction

Combustion tuning – where did it go? Nobody doing it.

Source testing – Once every 5 years, once/year…

This speaker- No measurement data – no reason for change/optimization Combustion is dynamic system – things change over time

Proposal – Implement periodic monitoring program for Combustion Tuning - for Compliance, for NOx reduction,

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History - Testing Programs for Portables

European TUV – Approval for official Source testing (NOx & CO) since early 1990s (yearly testing approvals)

1996 GRI tested 6 models of compliance level “Emission Analyzers”. Results of testing showed consistent laboratory performance, typically within 1%

Result = development of referenced-level test method

2000 EPA ETV tested seven multi-gas models 6 analyzers within about 1% of reference, 1 within 5%

http://www.epa.gov/etv/vt-ams.html#pmgea

Result of the ETV testing = ………

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EPA‘s – Revised Method 7E

Method 7E – DETERMINATION OF NITROGEN OXIDES EMISSIONS FROM STATIONARY SOURCES

(INSTRUMENTAL ANALYZE PROCEDURE)

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EPA‘s – Revised Method 7E

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What EPA said about Electrochemical Analyzers

In its Final Rule for the Update of Continuous Instrumental Test Methods, the EPA stated:

“The electrochemical analyzer has been shown capable of producing reliable results in an Environmental Technology Verification study and we do not believe special restrictions should be placed on this technology.”

Federal Register Vol 71/ No 93, Page 28084

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White Paper – 2009 Gas Machinery Conference - Atlanta

Title - Exhaust NO/NOx Ratio from Lean Burn Natural Gas Engines

NO2 to NO ratio can be significant with ultra lean conditions or when using oxidation catalyst.

Large NO2/NOx ratios may results in additional uncertainty in NOx Measurements since the most common technique chemiluminescence was developed for Low NO2/NOx ratios.

Three measurement technologies were tested - Chemiluminescence- Electrochemical cell- Fourier Transform Infrared (FTIR) Spectroscopy

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White Paper – 2009 Gas Machinery Conference - Atlanta

- Conclusions

“The portable analyzer with chemical cell technology was found to be the most accurate for measuring exhaust NOx with Large NO2/NOx ratios.”

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States Identify Compliance Problems

Numerous state agencies use portable electrochemical analyzers to identify non-compliance - three examples

Oklahoma - DEQ (stationary engines)

Texas – TCEQ – (stationary engines)

California - SCAQMD - (stationary engines & boilers)

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States Identify Compliance Problems

Oklahoma DEQ – Original intent to develop a one-year training program for inspectors. Included Spot checks with portable analyzer to better understand gas transmission market

Findings of program– Found approximately 75% of sources not meeting emission limit

Results – News quickly spread of agencies “spot checking” ability– 90% compliance after one year of spot checking.– Unintended - Companies developed new programs (i.e trained

employees to be engine analyst” & “emissions analyst”.

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States Identify Compliance Problems

Texas TCEQ – Used portable analyzers for spot checking sources. If source out of compliance, reason to cite and require immediate 3rd party source testing.

Findings of program– Similar to Oklahoma experience - Found approximately 75% of

sources not meeting emission limit – Tested a small V8 engine - found it comparable to title V source

Results – News quickly spread of agencies “spot checking” ability– Approximately 90% compliance after one year.– Companies developed new programs (i.e - engine analyst” &

“emissions analyst”.

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Draft 2007 AQMP - Sufficient emissions reductions had not been identifiedIdentify sources by unannounced emission tests by AQMD - Target Stationary Engines then Boilers

States Identify Compliance Problems

Rich-Burn Engines

Lean-Burn Engines

No. of Tests 215 11

No. of ICEs Tested 180 11

% of Tests on ICEs with BACT Limits

79% 91%

% Non-Compliance 51% 27%

% NOx Violations 40% 27%

% CO Violations 28% 0%

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Emission Exceedances

NOx CO

Rule 1110.2 Limits, ppm* 36-45 2000Typical BACT Limits, ppm* 11 70

Maximum Test Concentration, ppm* 850 12,500Average Violation Concentration, ppm* 137 2,520

Maximum % Over Limit 7,430% 18,400%Average % Over Limit 912% 1,830%

Tested Excess Emissions, Tons/Year 385 4,894* @ 15% O2

Major contributor for Non-Compliance

Engines loads change frequently. Many older air-to-fuel ratio (AFR) devices have difficulty controlling emissions with changing loads or detecting non-compliance operation

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Continuous Emission Monitoring – Put CO CEMS requirement back into rule (Require (CEMS for engines

with a combined rating of 1000 hp)

Amendments to Monitoring, Recordkeeping and Reporting

Increase frequency from every 3 years to every 2 years (or 8760 op. hrs) Multiple load tests No pre-test adjustment, no abort for non-compliance

• Required for engines with no CEMS• Determine parameter ranges for emission compliance over engine

load range (i.e.- O2 sensor voltage, cat. temps, reagent rate (if SCR), etc.

Source Testing Amendments

Inspection & Monitoring Plan

Compliance Amendment

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Daily monitoring and recording of engine and control equipment parameters, faults and alarms

Preventative and corrective maintenance and schedules Weekly Testing (or 150 hrs) using Portable Analyzer Monthly if three successive weekly tests – OK

Portable Analyzer Training Course Agency Certified Testers

Portable Analyzer Testing Protocol Developed Periodic Monitoring Protocol (for Boilers & Engines)

Amendments to Monitoring, Recordkeeping and Reporting

Inspection & Monitoring ( I & M ) Plan

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Technology - Nothing Measures Perfectly

All technologies have measurement variability in uncontrolled base forms.

• Temperature Influences (drift)• Cross-sensitivity (to other gases)• Flow sensitivity – must be controlled• Technology specific

• ..….saturation, sensor aging

• Manufacturer – expertise

Portable EC technology is no different.

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Manufacturing solutions - Analyzer design and manufacturing innovation help to eliminate measurement variability

ICAC Purchase Document GuidancePortable Analyzer for Combustion Emissions (PACE)

specifies analyzer requirements.

“Emission Grade Analyzers”

can eliminatemeasurement variability

Solution to Eliminate Measurement Variability

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Solutions to Eliminate Measurement Variability

Procedural solutions -Testing protocols• EPA Reference Method 7E• CTM - 030, ASTM D6522 (for reference level)• CTM-034 (for periodic monitoring) • State & Local protocols

Recommendation CA SCAQMD Periodic Monitoring Protocol

• 1110.2 for engines & 1146 for boilers • http://www.aqmd.gov/comply/formsbyrule.htm

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• Similar to Car Battery - Dissimilar metals set up potential current

• Electric current generated is proportional to gas concentration permeating through diffusion barrier (oxidization or reduction)

• Measured parameter is targeted through sensor chemistry

What is an Electrochemical sensor?

Tens of 10,000s used extensively Safety – Ambient air monitoring Combustion applications

Emissions & process monitoring

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Technology Specific – Solutions for Measurement Variability

Saturation (or over-exposure) of sensorAt extreme concentrations or long term exposure, the

electrolyte chemistry can be temporarily depleted. • Long-Term testing with low O2.

• Long term exposure to calibration gas (stability testing)

The fresh air purge is a process where the sensors “breath” ambient air to balance electrolyte.

• Extends sensor life & improves the accuracy.• Manufacturers’ recommended purge rates

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Methods to control temperature influence

Technology Specific – Solutions for Measurement Variability

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Methods to Prevent & Identify Cross-sensitive Responses

• Maintain Filters (scrubbers) - remove before depleted (i.e. NOx beads before the CO sensor)

• External filters – replace beads when color changes • Internal filters - remove interfering gases inside the

sensor

• Electronically cross compensate by measurement

• Identify cross sensitivity through the calibration procedure.

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EC sensors depend upon ambient conditions for proper diffusion into sensor. Extreme high or low sample flow rates (or pressure) can change diffusion rate.

Emission- Grade Analyzers - control flow rate through precision valves and/or orifice plates and flow rate through instrument is measured.

Flow Control and Monitoring

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EC sensors use chemistry for operation. The chemistry simply wears out, but wears out in linearly. No decrease in accuracy over time.

Solution for Aging Sensor

• Talk Louder

• Replace sensor• Plug & Play• New developments 3-year O2, 6-year other sensors

Sensor Aging

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Definition - Process of changing the hot, wet, dirty exhaust gas into a cool, dry, clean gas sample without loosing constituent concentration. Prime consideration in the design of an instrument to deliver accurate measurements

Electrochemical sensors require cool, dry gas delivered at proper flow and pressure.

Proper sample conditioning results in longer sensor life, higher accuracy and repeatability

Remove moisture continuously - Dry Basis for reporting

Sample Conditioning

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Sample Conditioning

Dry Basis Data – required by most permits Moisture acts as a diluent

Moisture reduces measured readingsWet Measurement may Result in False Compliance

Wet Basis Dry BasisOxygen 2.20% 2.53%

Carbon Dioxide 13.20% 15.23%Nitrogen 71.10% 82.05%

Carbon Monoxide 1.000% =10,000 ppm 1.115% = 11,150ppmOxides of Nitrogen 0.02% = 200 ppm 0.023% = 230 ppm

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Sample Conditioning

Ice Bath type

Peltier type

Heated Sample Lines

Permeation type

Peltier type

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Data acquisition has come a long way

•Look and remember it

•Chisel it into rock•1st binary code?

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Software has come a long way

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Software has come a long way

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SCR Sampling

Typical OutletGrid Setup

Data acquisition has come a long way

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Industrial NOx Testing applications

SCR Reactor Source: ABB Alstom Power

SCR Reactor Source: Riley Power Inc. 2000

Selective Catalytic Reduction (SCR)

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Principle of SCR Source: KAWASAKI HEAVY INDUSTRIES, LTD., 2004

Selective Catalytic Reduction (SCR)

Industrial NOx Testing applications

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NOx Tuning for Process Control (SCR)

Laptop - Controls analyzers – Simultaneously collects real-time emission data from up to 16 ports (from daisy-chained t350 analyzers)

Multiple (6 Point) Sampling Port

Samples from each point for ~ 1-2 minutes.

different depths of sample points

SCR Reactor

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“NOx” Instrument group

Calculation through a special program

Reactor profile Aim: Adjust Ammonia Whole area should be the same color (lowest NOx concentration here in blue)

NOx Tuning for Process Control (SCR)

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NOx Tuning for Marine Applications

NOx Technical code

TYPE Approval

GL Certificate approved

Exhaust Stack- Container Ship

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Benefits - Electrochemical-based Analyzers

Technology accepted by US EPA Accepted Periodic monitoring protocolsMeasures: NOX (NO, NO2), CO, CO2 & others

Cross Utilized for Process & Combustion OptimizationLower Cost Alternative $ 8 -12 K

Thank you for your time and attention

Testo Sparta NJ 800-227-0729

www.testo350.com

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Questions:

Testo Inc.40 White Lake Road,Sparta NJ 07871800-227-0729www.testo350.com

Thank you for you time and attention.