Replacing a Stack Gas Flow Hardware Device with PEMS

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PNWIS & AWMA 52nd Annual Conference | Portland, Oregon The Nines Hotel | November 7 through 9, 2012

Presented by:

Brian Swanson, President

CMC Solutions, L.L.C.

Replacing a Stack Gas Flow Hardware Device with PEMS

1


Introduction CMC Solutions was retained to perform a

demonstration of a statistical hybrid predictive emissions monitoring system (PEMS) under 40 CFR Part 75, Subpart E.

The PEMS was deployed in September of 2010 for stack gas flow and pollutant emissions.

The demonstration confirmed that the PEMS passes all the statistical tests for the 720 hour demonstration period.


PEMS Technology Early models included first principle theoretical

models by OEMs.

Commercial PEMS available on the market include first principles and empirical models.

Empirical models such as neural network and statistical hybrid have passed EPA requirements.

Hundreds of PEMS are used in the U.S. today for compliance monitoring under EPA rules.


Performance Testing Methods 40 CFR Part 75, Subpart E demonstration – 720 hours

of PEMS vs. CEMS data, 24 hours each additional fuel

PS-16 Relative Accuracy Test Audit (RATA)

27 runs (9 at each of three loads)

Relative Accuracy FLOW PEMS was 2 percent

F Test

Correlation

Data Availability


PS-16 RATA Testing 27 Run RATA Testing


PEMS QA Sensor validation – model envelope excursions for

empirical models

Sensor quality assurance and PEMS QA programming

Periodic Audits (RAA)

Annual recertification (RATA) tests

Model updates and tuning of empirical models


PEMS QA Programming QA Plan developed around input parameters

INPUT DESCRIPTION UNITS MIN MAX

Input24*

Unit Load Set Point

MW

2.34

99.92

Input56* Total Gas kscfh 0.60 1003.96

Input4 Boiler Feed-water flow kpph 0.00 748.10

Input22 Unit Megawatts MW 0.00 101.92

Input23 Unit Megawatt Demand MW 0.00 100.09

Input34 1st Stage Pressure psi 0.00 1371.40

Input37 Hot Reheat Steam Pressure psi 0.00 442.30

Input45 Top Wind-box Pressure inwc 1.20 37.60

Input46 MID Wind-box Pressure inwc 1.30 27.12

Input47 BTM Wind-box Pressure inwc 0.10 29.60

Input60 Auxiliary Steam Pressure DMD % 0.00 100.00

Input74 Steam Flow kpph 1.30 684.70

TABLE II - MODEL ENVELOPE


Results The raw minute data output from the CEMS data

acquisition system was quality assured. The PEMS was deployed in the September of 2010 for stack gas flow and pollutant emissions.

An X-Y plot of the PEMS values against the CEMS values is presented. Also included in the report is a graph of the percentage differences between the CEMS and PEMS for each hour record.


Performance Evaluation Statistical Hybrid PEMS met requirements.


Performance Evaluation Stack Gas Flow PEMS vs. CEMS XY Plot

0

50

100

150

200

250

300

350

400

450

500

0 50 100 150 200 250 300 350 400 450 500

Stac

k Fl

ow

-CEM

S kM

3/h

r

Stack Flow-PEMS kM3/hr


Performance Evaluation Stack Flow Rate PEMS vs. CEMS X-Y PLOT.

-250

-200

-150

-100

-50

0

50

100

150

200

250

1 51 101 151 201 251 301 351 401 451 501 551 601 651 701

Pe

rce

nta

ge

Dif

fere

nc

e C

EM

S v

s P

EM

S

Hours


Performance Evaluation Statistical Hybrid PEMS met requirements.

Test Value EPA Limit High/Low Limit Pass/Fail

F Test

0.845

<

0.88 High Limit Pass

Correlation

0.899

>

0.8 Low Limit Pass

Data Availability

0.97

>

0.9 Low Limit Pass

TABLE I – 720 HOUR STATISTICAL ANALYSIS


Conclusion CMC Solutions PEMS was capable of meeting the most

stringent requirements for monitoring stack gas flow on gas and oil fired boilers.

The PEMS was reliable and accurate.

The demonstration confirmed that the PEMS was accurate under both base-load and startup conditions along with transitional load periods.


Introduction

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Federal regulations require continuous monitoring of NOx , CO, SO2, O2 and/or CO2 from industrial processes in the United States

A statistical hybrid PEMS has been employed at a number of compliance sites in the United States

Brief History of CEMS/PEMS development PEMS have been used for compliance since the 70’s

Advantages of PEMS PEMS are less Costly PEMS are easier to maintain


CEMS Components / Maintenance

Sample Probe

Umbilical

Analyzers

Gases

Pumps

Filters

Controllers

Computer

Air Source

Spare Parts


Why consider PEMS?

SmartCEM® is a proven and patented product Guaranteed to meet U.S. EPA regulations Supported by a network of professionals Virtually no maintenance or operational costs PEMS model can be updated by owner

In addition, SmartCEM® can be setup quickly

The model is developed and retrained onsite Replaces your existing CEMS No spare parts, analyzer repairs, emergency service


PEMS History and Use in Compliance Monitoring for 40 CFR Regulations

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PEMS Design and History

PEMS are not new, they evolved … Introduced in the 1970s

Parametric and First Principles initially

First PEMS were NSPS (40 CFR Part 60)

OEM models, GE, Solar, others (~ 500 worldwide)

Empirical Methods introduced in the 1980s

PEMS on the market today are theoretical First Principles (Parametric) and Empirical (Neural Network, and Statistical Hybrid Methods)


Regulatory Selection Criteria Monitoring Primary Pollutants (NOx, SOx, CO)

PEMS may be used as an alternative to CEMS for all gas or oil-fired boilers and turbines

Parametric, PEMS, or CEMS approaches can be used for all smaller units (< 100 mmBTU)

CEMS must be used on some units that fire solid fuels such as municipal waste (> 250 mmBTU)

Local agencies may require monitoring of specific pollutants in non-attainment (SO2, NH3, CO or VOC PEMS optional measurements)


PEMS Regulatory Selection Matrix 40 CFR Part 75 Yes, as 40 CFR Part 75, Subpart E

P1, P2, and Subpart H alternate Electrical Generating Units

40 CFR Part 60 Yes 40 CFR Part 60, Appendix B, PS-16

Subpart Da, Db, Dc Boilers (All Fuels)

40 CFR Part 60 Yes 40 CFR Part 60, Appendix B, PS-16

Subpart GG or KKKK Turbines (Gas and Oil Fired)

Clean Air Interstate Rules Yes, as 40 CFR Part 75, Subpart E

CAIR alternate All Affected Units (All Types)

Maximum Achievable Technology Yes, as 40 CFR Part 60, Appendix B, PS-16

MACT alternate Boilers (All Fuels)

Continuous Assurance Monitoring Yes All Affected Units (All Fuels)

CAM

Voluntary Superior Monitoring Yes All Affected Units (All Fuels)

VSM


PEMS Classifications

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Parametric Systems

Predictive Systems

Theoretical “First principle” method

Empirical Neural network

Statistical hybrid


Parametric Systems

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Features of Parametric Systems

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Simple formulaic approach

Accuracy is very limited

No flexibility – if signal is lost, no prediction is available

Do NOT predict excess emissions

Are NOT certified as an alternative to CEMS

Acceptable for peaking units with less than 10% operating time in a given year


Theoretical Predictive Systems

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Features of Theoretical PEMS

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Complex formulaic approach

Accuracy is maintained when unit is operated as it was in the factory or under similar ambient conditions

No flexibility – if critical signals are lost, prediction is lost

Can only be verified against limited factory test data

Can be certified as an alternative to CEMS

Many implementations have been removed due to failure to meet ongoing quality assurance tests or respond to unit changes that are not reflected in the formula

Expensive to maintain and requires specialized staff


Empirical Neural Network Predictive Systems

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Features of Neural Network PEMS

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Complex neural network approach

Requires extensive up front testing with specialized staff onsite in an iterative process

Accuracy is maintained when unit is operated as it was in the initial setup or under similar ambient conditions

Can be certified as an alternative to CEMS

Some implementations have been removed due to expense and support required to pass QA audits

Expensive to maintain and requires specialized staff


Empirical Statistical Hybrid Model

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Features of the Statistical Hybrid

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Robust Model that is accurate across the full load of the unit including all normal operating conditions and during transitional states such as startup and shutdown

Equivalent accuracy as a CEMS with superior reliability

Flexibility to be implemented using existing instrumentation

Can certify as an alternative to CEMS

Systems in operation around the world today on gas turbines both in the U.S. and in the E.U.

Virtually no maintenance – no specialized staff required and can be maintained by operators or other staff onsite


Statistical Hybrid Advantages

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Requires no specialized staff to maintain

Model can be developed without a great deal of knowledge of the underlying process or chemistry

Highly reliable with options for data recovery

Minimize or eliminate monitor downtime

Can generate predictions with a variety of inputs

Can generate predictions with inputs that fail

Can be retrained by non-specialized staff


Features of the Statistical Hybrid

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Can be assessed using quality control procedures defined to meet the requirements of U.S. EPA

Can be developed and retrained by non-technical onsite staff or consultants using third party test data during normal operations

Can be tested against EPA reference methods and has been demonstrated at multiple sites on various gas turbine classes to meet 40 CFR Part 75, Subpart E


Example Applications

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Applications

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Gas and liquid fuel fired turbines

Gas and liquid fired boilers

Gas fired ethanol plant boilers

Petroleum refinery processes

Other continuous systems


Gas and Liquid Fired Turbines

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Applied to turbines from 60kW to 180 MW

Fuels included natural gas, deisel, and fuel oil

Equipped with a variety of control technologies including dry low NOx, steam and water injection, SoloNox, and post combustion SCR

Turbines were from a variety of manufacturers


NOx PEMS Time Plot

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NOx PEMS XY Plot

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Gas and Liquid Fired Boilers

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Applied to boilers from 100 mmBTU to 750 mmBTU

Fuels included natural gas, blast furnace gas, coke oven gas, refinery gas, and fuel oil

Equipped with a variety of control technologies

Boilers were from a variety of manufacturers

PEMS developed with existing instrumentation and input parameters readily available from distributed control system


Oil Fired Boiler O2/NOx Time Plot

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Oil Fired Boiler CO/CO2 Time Plot

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RATA Test Results

Relative Accuracy Test Audit (RATA) was conducted to certify the results

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RATA Test Procedures

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Uses U.S. EPA reference methods (RM)

The RM was compared to the PEMS predicted emissions

The process was tested under three operating loads

3 or 4 test runs conducted at each load with a duration of 21 minutes each


RATA Conducted on 3 Processes

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Ethanol plant boiler rated at 100 mmBTU/hr located in Western Iowa

170 MW combined cycle turbine at a power plant in Detroit, Michigan

750 mmBTU/hr boiler firing pipeline natural gas and blast furnace gas


RATA at Ethanol Plant

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0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

0.09

0.1

1 2 3 4 5 6 7 8 9 10 11 12

Test Run

NO

x lb

/mm

btu

RM

PEMS


RATA on Power Plant Turbine

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0.027

0.028

0.029

0.030

0.031

0.032

0.033

0.034

1 2 3 4 5 6 7 8 9

Test Run

NO

x lb

s/m

mb

tu

RM

PEMS


RATA at Power Plant Boiler

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0.000

0.020

0.040

0.060

0.080

0.100

0.120

0.140

0.160

1 2 3 4 5 6 7 8 9

Test Run

SO

2 l

b/m

mb

tu

RM

PEMS


PEMS Quality Assurance

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Instrumentation was subjected to annual QA

QA follows 40 CFR Part 75, Appendix B

QA manual is prepared and placed next to PEMS server for documenting all QC activity

System maintenance, database maintenance, and data backup procedures are instituted

All PEMS QC procedures and audits are documented in QA manual


Summary

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Statistical hybrid PEMS have been successful in meeting the requirements of the U.S. emission trading program

PEMS achieve very high accuracy levels

PEMS demonstrate superior reliability

PEMS are certified as an alternative to CEMS

PEMS are a cost-effective alternative to a CEMS


PEMS vs. CEMS XY Plot

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Concluding Remarks

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Advanced empirical PEMS have been used successfully in the U. S. for 40 CFR Compliance

PEMS achieve very high accuracy levels

PEMS demonstrate superior reliability

PEMS can be certified as an alternative to CEMS

Some PEMS require no specialized support making them ideal for offshore and remote applications

A robust statistical hybrid model is a cost-effective solution for continuous monitoring applications


Questions?

CEMS? , or … PEMS!

Which would you prefer, if you had a choice -

Engineering

Replacing a Stack Gas Flow Hardware Device with PEMS