Berthold Andres

Consulting für Emissions- und Prozessmesstechnik

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New Requirements

for the Measurement of

Ammonia Emissions

CEM 2014 / 14. May 2014

Dr. Berthold Andres

Consulting für Emissions- und Prozessmesstechnik

63599 Biebergemünd, Hufeisenstrasse 9

Germany

Berthold Andres

Consulting für Emissions- und Prozessmesstechnik

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Content

Requirement for ammonia emission monitoring in the last

BREF draft for certain large combustion plants (LCP)

was the motivation for this paper

Requirements in BREF draft for LCPs

Measurement of ammonia in a DeNOx plant

AMS for emission and process monitoring of ammonia

MCERTS and UBA/TÜV certified AMS for ammonia

Comparison of different measuring principles

Summary

Berthold Andres

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Draft BREF for LCP from June 2013

In June 2013 the European IPPC Bureau published the

draft 1 for the Best Available Techniques Reference

Document (BREF) for large combustion plants

The draft BREF requires the measurement of ammonia

(NH3) as slip control for LCPs using DeNox

technologies SNCR and SCR

Proposed BAT-AEL (best available technology -

associated emission limit value) is both 5 mg/m³ or less

as yearly average for existing and new plants in most

LCP applications

SCR = Selective catalytic reduction (reduction of NOx with catalyst)

SNCR = Selective non-catalytic reduction (reduction of NOx without catalyst at about 800 to 1.000°C)

Berthold Andres

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Backgound for Ammonia Measurment

Limit ammonia slip in LCPs with DeNOx abatement

Emission of ammonia is not a result of the combustion

of fossil fuels, but of incomplete reaction of ammonia in

the de-nitrification process

Ammonia or Urea is used to reduce NOx produced by

the combustion process:

4 NO + 4 NH3 + O2 → 4 N2 + 6 H2O

Ammonia slip at SCR and SNCR installations rises with

an increasing NH3/NOx ratio, but also with decreasing

catalyst activity

Ammonia concentration is usually kept below 5 mg/m³

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Measurement of Ammonia in DeNOx

Plants

Source: Siemens AG, Industry Automation Division

Process

Emission

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Advantages for Ammonia slip control at DeNOx

Ammonia slip causes following problems High ammonia concentrations in the flue gas cause build-up of

ammonia bisulfat (NH4HSO4) blockage of abatement system

higher maintenance

Higher concentration of (NH4HSO4) reduces quality of the fly ash

Bad smell of the flue gas in surrounding areas

Avoidable too high cost for ammonia for the abatement system

Ammonia slip measurement directly after DeNOx gives

additional information on the abatement performance,

depending systems used Efficiency of SCR catalyst

Reaction conditions in SNCR

Target is reduction of ammonia slip with controlled

process conditions

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Requirements for NH3

Measuring Principles

Salt formation and high water solubility of ammonia

are a big challenge for ammonia measurement in

required very low concentrations of few mg/m³

Hot extractive or in-situ AMS to avoid loss of ammonia in the

sampling system

Salt formation (especially NH4HSO4) must be avoided

Hot measurement & sampling > 180°C required

Fast measurement for process control

AMS for regulated sources require certification according to EN

15267 (resp. “Bekanntgabe” through the German UBA)

Standardization of the measuring result requires for hot

measurements additionally the determination of the water content in

the sampling gas

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Common Measuring Principles for NH3

FTIR (Fourier Transform Infra Red spectroscopy)

NDIR Photometer with GFC (Gas filter correlation)

CLD (Chemiluminescence Detector) with NH3 converter

TDLS (Tunable Diode Laser Spectroscopy)

Berthold Andres

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FTIR (Fourier Transform IR Spectroscopy)

FTIR are usually hot extractive AMS

For the measurement of NH3 as very water soluble component it is

absolutely required to maintain at least 180°C within the complete

system

Source: ABB Automation GmbH

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FTIR – Advantages and Limitations

Advantages Field proven solution with > 1.000 installations in Europe (not all NH3)

Simultaneous measurement of NO, SO2, HCl, NH3, CO, CO2, CH4,

etc. as required at waste incinerators, resp. large combustion plants

Extractive system allows devices for the verification of zero and span

according to EN 14181 QAL3

cost effective and simple solution instead of calibration gases

Limitations FTIR are rather expensive AMS

limits the use of FTIR – at least today – to few emission

monitoring applications (multi component, demanding components)

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NDIR Photometer with Gas Filter Correlation

Measurement is hot extractive, similar to FTIR AMS

Same requirements for hot sampling and measurement > 180°C

Source: Sick AG

Berthold Andres

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NDIR with GFC – Advantages and Limitations

Advantages

As for FTIR, these AMS allows devices for the verification of zero

and span according to EN 14181 QAL3

cost effective and simple solution instead of calibration gases

Lower cost compared to FTIR

Limitations

Some components like HF can not be measured with required

sensitivity

additional AMS for these components increase complexity

and cost for this measuring principle

Berthold Andres

Consulting für Emissions- und Prozessmesstechnik

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TDLS (Tunable Diode Laser Spectroscopy)

In-situ measurement direct at the stack

Source Siemens AG, Industry Automation Division

Berthold Andres

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TDLS - Advantages and Limitations

Advantages Direct measurement in stack reduces substantially loss of ammonia

Suitable for fast process measurement

Simple system design without sampling system

Some designs allow multipoint measurement with one analyzer

Simultaneous measurement of ammonia and water content

(standardization to reference conditions)

Limitations No multicomponent measurement possible

individual AMS increases system complexity

Some components cannot be measured with required sensitivity

QAL3 testing for complete system rather difficult

removal of AMS from stack may be required

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CLD with Ammonia Converter

Step 1: Conversion of ammonia to NO at the probe

Step 2: Alternating measurement with bypass

Total NOx incl. NH3 through the converter path

Original NOx content in sampling gas via bypass

NH3 concentration is the difference of both measurements

Currently ISO TC 146 SC1 generates new Standard for ammonia AMS

Mainly used in Japan and in the US

Berthold Andres

Consulting für Emissions- und Prozessmesstechnik

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CLD& Converter - Advantages and Limitations

Advantages Direct conversion of NH3 to NO is major advantage

no loss due to high water solubility

Conventional sampling system with cooler eliminates the requirement

for water content measurement

Limitations Small signal for ammonia in high NOx background

Is overall uncertainty sufficient?

Alternating measurement results in higher response time

Complex system with sampling switching and two converters for NH3

and NO2

Only very limited experience in Europe

Currently no EN 15267 certified AMS based on this measuring principle

Berthold Andres

Consulting für Emissions- und Prozessmesstechnik

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Certified Emissions Monitoring Systems

IED 2010/75/EU, national regulations and EN 14181

require certified AMS at regulated sources

Based on EN 15267 and EN 14181 there are two

certification systems for AMS in Europe UBA / TÜV certification in Germany

MCERT / Sira certification in UK

Both systems are very similar and are accepted as alternatives

nearly by all EU countries

But: UK and Germany require their own certification

Revised EN 14181 will require for new installations

certified AMS according to EN 15267

older national MCERTS & UBA/TÜV certificates

will only be valid for installed AMS!

Berthold Andres

Consulting für Emissions- und Prozessmesstechnik

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Comparison of Ammonia Measuring Principles

Performance criteria FTIR TDLS NDIR with

GFC

CLD with

converter

No NH3 loss in sampling system (e.g. insitu, >

180°C or conversion) +*) + + +

Suitable for multi component systems + - + -Suitable for single component systems - + - +Suitable for process measurement (fast, high

dust and water vapor load) 0 + 0 0

Suitable for emission monitoring (with

certification acc. EN 15267 or national) + + + -

Simple extension with additional measuring

components + - 0 -

Suitable for additional HF measurements for e.g.

waste incinerators + + - -

Simple use of test gas for QAL3 + - + +Use of other reference materials for QAL3

instead of test gases + - + -

*) „+“ means suitable, „0“ means suitable with restrictions, „-“ means less or not suitable”

Berthold Andres

Consulting für Emissions- und Prozessmesstechnik

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Summary

BREF draft from June 2013 requires the measurement of

ammonia emissions for certain large combustion plants for

ammonia slip control

There are several AMS available for ammonia with a lowest

certified range of 0 to 10 mg/m³, resp. 0 to 15 mg/m³, but some

certificates are based on older national certification systems

Requirements from the BREF draft for ammonia can be fulfilled

with commercially available and EN 15267 certified AMS

In-situ TDLS measurement systems are rather the preferred

solution for process control

As multicomponent AMS, hot extractive FTIR or NDIR/GFC are

rather the preferred solution for tail-end emission monitoring

Berthold Andres

Consulting für Emissions- und Prozessmesstechnik

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Thank you very much for your attention!

Dr. Berthold Andres

Consulting für Emissions-

und Prozessmesstechnik

Hufeisenstrasse 9

D - 63599 Biebergemünd

Tel. ++49 (0) 6050 – 90 98 626

berthold.andres@euro-analytics.de

www.euro-analytics.de