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Predictive Emission Monitoring (PEM):Suitability and Application in View of U.S. EPAand European Regulatory Frameworks

Thomas EisenmannDr. Roland Bianchin

David Triebel

CEM 2014 - Istanbul, 14th May 2014

PEMS provide a reasonable alternative to CEMS (AMS) where there is

a reliable and predictable correlation between plant operating

conditions and emissions.

Predictive Emission Monitoring Systems (PEMS) are used for

continuous monitoring of emissions at stationary sources as an

alternative and backup for ‘Continuous Emission Monitoring

Systems’ (CEMS, in Europe usually AMS - Automated Monitoring

System).

PEMS define the relationship between a number of characteristic

process parameters of an emission source and the corresponding

emission concentration.

Introduction

This is generally applicable to gas and oil

fired plants, e.g. Boilers

Turbines

Reciprocal Internal Combustion Engines

(RICE)

Heaters

Furnaces

Ships

Just to name a few

Introduction

Introduction

Control Building

Fuels: Gas, Oil etc.

Fuel FlowEmission

Source

NOx, CO, O2

etc.

DCS

DAHS plus Emissions Model

Inputs (read only)

Data Interface by bus

systems (Modbus,

Profibus, OPC etc.)

Control

D-DAS 2010 D-PEMS

DAHS: Data Acquisition &

Handling System

DCS: Distributed Control System

CEMS as well as PEMS in the USA and countries

following U.S. Environmental Protection Agency (EPA)

regulations are mainly governed by

40 C(ode)F(ederal)R(egulation) Part 60 (Part 63) and

40 CFR Part 75.

PEMS as Alternative Monitoring Method (AMS) is

specifically addressed in

Part 60 Performance Specification PS-16 and

Part 75 Subpart E Alternative Monitoring Methods.

Regulatory Framework – U.S. EPA

New Source Performance Standard - NSPS,

promulgated first 1971

US EPA Part 60

Subparts for each type of source with e.g. subpart D covering boilers, GG

covering stationary gas turbines and J Petroleum Refineries

Requires Continuous Monitoring of Primary Pollutants (NOx, SO2, CO,

Opacity and VOC)

Part 60 is flanked by a series of test methods for emission measurements

and 13 (17) Performance Specifications

Industrial Units >100 mmBTU (about 29 MW), in some case also to smaller

sources (e.g. Subpart Dc covering small industrial boilers)

Performance Specifications

www.epa.gov/ttn/emc

• Performance specifications are used for evaluating the

acceptability of CEMS (and PEMS) at the time of or soon after

installation and whenever specified in the regulations;

• Quality assurance procedures in 40 CFR Part 60 Appendix F

are used to evaluate the effectiveness of quality control (QC)

and quality assurance (QA) procedures and the quality of data

produced by any CEMS / PEMS.

Continuous Emission Monitoring, originally published in 1993

US EPA Part 75

Continuous Emission Monitoring (CEM) and reporting requirements under EPA’s

Acid Rain Program (ARP), instituted in 1990 under Title IV of the Clean Air Act

ARP regulates electricity generating units (EGUs) that burn fossil fuels and that

serve a generator > 25 megawatts

It requires continuous monitoring and reporting of SO2 mass emissions, CO2 mass

emissions, NOx emission rate, and heat input

Included is a cap and trade program as market-based approach to reducing

emissions

Emissions data must be reported for each operating hour, without exception

Each CEMS or PEMS must be equipped with an automated DAHS

Regulatory Framework – Europe

PEMS in compliance with

prEN 264153 (WG 37) “PEMS Standard”

IED 2010/75/EU

The Large Combustion Plant Directive LCPD (2001/80/EC)

EN 15267. Applicability of minimum requirements as per Part 3 needs to

be reviewed.

EN 14181. Applicability of QAL1?

The Waste Incineration Directive WID (2000/76/EC)

CEN / TC 264 WG 37 “PEMS Standard”

• CEN (European Committee for Standardization) established

within the Technical Committee (TC) 264 „Air Quality“ the

working group WG37

• Main stimulus came from the Netherlands. They use PEMS in

particular for refinery / petrochemical applications

• The normative work started of from a Dutch draft and is

entitled

prEN 264153 Predictive Emission Monitoring

Systems (PEMS) – Applicability Execution and

Quality Assurance• Legal basis is the EU directive 2010-75-EU for industrial

emissions

• Four Task Groups:

Building a PEMS

QA of PEMS

Validation of a PEMS

Generic example of execution and QA of a PEMS.

• WG37 standard must accommodate the one-of-a-kind

uniqueness of PEMS for a specific plant;

• This is a particular challenge for dealing with EN15267 Part 3

and the array of questions concerning type tests;

• Detailed suitability of QAL2 test schemes of EN14181 will be

investigated

CEN / TC 264 WG 37 “PEMS Standard”

U.S. EPA

Part 60 (PS-16) as well as

Part 75 (Subpart E)

focus primarily on a

certification for a specific plant (initial RATA).

VGB PEMS Project

R&D project funded by VGB Power Tech, the European technical association for

power and heat generation:

“Evaluation of the application of Predictive Emissions

Monitoring Systems (PEMS) in Europe taking into account the

boundary conditions of the Standards EN 14181 and EN 15267“

Conducted at two combined cycle power plants in Germany

Major objective was to compare PEMS with plant CEMS and the results of a

QAL2 conducted by an independent, accredited stack tester

Lessons learned gave good insight, where improvements can be achieved and

what needs to be observed to successfully conduct the PEMS implementation

process

A detailed assessment of performance criteria in EN15267 Part 3 with respect to

their applicability for PEMS can be found in the final report of TUEV Rheinland

Some Other PEMS Relevant Activities

Another working group, WG 9 “Quality assurance of automated

measuring systems (Amendment to EN14181:2004)” within TC 264

is related to WG 37. It is working on a draft standard for data

acquisition and handling systems (DAHS).

To address communication and digital interfaces, a quite significant

issue also for PEMS and their integration in plant-wide IT networks,

the Association of German Engineers VDI has published a series of

guideline documents as VDI 4201, Part1-4

Practical Minimum Performance Requirements I

Units: Any unit wanted by the operator or stipulated by environmental

regulation (ppm, mg/Nm3, g/GJ, etc.).

Best model selectable and application specific to provide the best fit

to a plant process and the most economical way.

Components: NOx / O2 / CO / SO2 / CO2 / NH3 / HC / VOC / HCHO /

others as needed. Model parameters individual per component

Ranges only limited by used analyzer for the training data set. Model

building incorporating data from multiple analyzers and multiple

ranges. Ranges fully adjustable.

Sensor Validation System: Determination of defective and erroneous

process sensors and inputs. PS-16 requires it daily, recommended is

once per minute. Redundant sensors and analysis of reliable inputs.

Accuracy and precision as per PS-16 /Subpart E / CEMS standard

Response time: 99,9 % less than 1 sec.

Executable on standard server and workstation hardware

Visualization (graphic user interface - GUI) By means of a data

acquisition systems, but also own (simple graphic representation)

Prevention of data manipulation and unauthorized reproduction of

licenses, e.g. log file recording immutably all modification of software

or model, model encryption, new revision number, license key etc.

All standard interfaces, e.g. OPC, ModBus, Profibus etc.

Data availability 99 % +

Measurement frequency 1 sec.

Practical Minimum Performance Requirements II

Quality Assurance

PEMS is an Analyzer!

Measure Frequency

Sensor Validation Once per minute, minimum daily

Relative Accuracy Audit RAA Quarterly / Monthly

Relative Accuracy Test Audit RATA Annual

EN 14181 QAL1 Uncertainty: PEMS Model Building

EN 14181 QAL 2 Initial calibration

EN 14181 QAL 3 Periodic checks at regular intervals

EN 14181AST Annual

Initial

certification

Sensor

Validation

Quarterly

RAAs

Subsequent

RAAsYearly RATA

Yearly Relative Accuracy

Test Audit (RATA):

Minimum 9-runs at the

normal operating level.

According PS-16

(continual

compliance):

Minimum 27-run

(9 runs at three

operating levels

of “the key

parameter that

most affects

emissions”)

relative accuracy

test (RAA).

Minimum daily

check,

recommended

once per minute

or once per

monitoring

cycle.

RAAs in the first

year after initial

certification:

At least three 30-

minute portable

analyzer or

reference method

(RM)

determinations*.

All quarterly RAAs

passed in the first

year and the RATA

in the second year:

One may elect to

perform a single

mid-year RAA in

the second year.

Quality Assurance EPA Part 60

*The average of the portable analyzer or Reference Method

determinations must not differ from the PEMS average value

by more than 10 percent or the test is failed

Step 3

Step 1

Step 2

Step 4

Step 5

Quality Assurance EPA Part 75

Subpart E

Approval

720 operating hour

demonstration that

the AMS has same

or better precision,

reliability,

accessibility, and

timeliness (PRAT) as

a CEMS

Alternative Monitoring System (AMS)

Compliance

Data Availability

Valid paired data for

at least 90 % of the

minimum 720

operating hours

Reliability

Valid one-hour

averages for

minimum 95.0 % of

operating hours for

one year

Sensor Validation

System

shall include an alarm

to inform the operator

when sensors need

repair and when the

PEMS is out-of-

control. Sensor failure

test.

RAA & RATA

Semi-annual or annual

RATA

3-run (minimum) RAAs

in every month in

which the unit operates

for at least 56 hours

(may be only for ozone

season May-

September or waived

for a three-month RAA)

Normal operating

levels

Summary and Comparison PEMS – CEMS

Common

FeaturesCEMS / PEMS

ContinuousBoth methods can be used for continuous emissions

monitoring.

Plant

TypesFor all oil- and gas-fired sources.

Accuracy /

Precision

Accuracy and precision are comparable provided that the

same quality assurance is applied.

Quality

assurance

Securing data quality with procedures of EN14181 /

requirements of EN 15267 (EU) as well as Part 60 / Part 75

RATA / RAA (USA)

Data

Acquisition

For data representation and reporting of monitoring results,

use of data acquisition and handling systems.

Summary and Comparison PEMS – CEMS

Differences CEMS PEMS

Hardware

• Gas Analyzers

• Accessories like probes, heated

lines, racks, shelters etc. needed

• Standard server hardware with means

for data back-up and securing data

integrity

Application

CEMS more universally applicable:

• Plants fired with variable solid

fuels

• Components like particulate

matter and Hg

• Basically not suitable for solid,

moisture absorbing fuels

• Not applicable at e.g. waste

incinerators

• Restricted for coal-fired plants

Cost

• Capital cost: Approximately 50 % of a comparable CEMS. In case of model

transferability or for ex-proof areas, cost difference may even be much higher

• Operations and maintenance: Approximately 10-20 % of CEMS cost

• Quality assurance: No cost difference

Quality

assurance

• EU: Type approval

• U.S. Daily Zero and Span Check

(Part 60)

• EU: EN15267-3 may not be reasonably

applicable due to the plant specific, one-

of-a-kind characteristic of PEMS

• U.S. Sensor Validation System (PS-16,

Subpart E). Resilience to input failures.

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Predictive Emission Monitoring (PEM):Suitability and Application in View ofU.S. EPA and European Regulatory Frameworks

CEM 2014 - Istanbul, 14th May 2014