CODEL
Total Solutions - Total Confidence
CODEL International LtdStation Road, Bakewell,Derbyshire DE45 1GEEnglandTel : +44 (0) 1629 814 351Fax : +44 (0) 8700 566 307e-mail : [email protected] : www.codel.co.uk
CODEL
Continuous Emissions Monitoring
Customer requirements for continuous emissions monitoring
• Measurement of all pollutant gases
• Measurement of solids emissions
• Measurement of complementary parameters
• Measurement to comply with legislation
• Secure data presentation
• Maximum reliability
• Low cost of ownershipCODEL
• Fully integrated system
• Seven gas species in a single analyser
• Particulate measurement
• Pollutant gas flow measurement
• Automatic data normalisation
• Five-year data logging & reporting
• Automatic calibration verification
CODEL
CODEL SmartCEM
Gaseous species• Carbon monoxide CO• Nitric oxide NO• Nitrogen dioxide NO2• Sulphur dioxide SO2• Hydrogen chloride HCl• Methane CH4• Carbon dioxide CO2• Water vapour H2O
CODEL
Available techniques for continuous gas analysis
• Infrared spectroscopy• Ultraviolet spectroscopy• Electrochemical cell• Solid electrolyte cell• Paramagnetic • Tuneable diode laser• Chemiluminescence• Flame ionisation devices
CODEL
Infrared spectroscopy
CODEL
Suitable for measuring many different species
wavenumber = 1/wavelength in cm = 10000/wavelength in μm
Infrared spectroscopy
CODEL
Suitable for measuring many different species
wavenumber = 1/wavelength in cm = 10000/wavelength in μm
H2OH2O and CO2
Infrared spectroscopy
CODEL
CO
Suitable for measuring many different species
wavenumber = 1/wavelength in cm = 10000/wavelength in μm
H2OH2O and CO2
Infrared spectroscopy
CODEL
CO NO
Suitable for measuring many different species
wavenumber = 1/wavelength in cm = 10000/wavelength in μm
H2OH2O and CO2
Infrared spectroscopy
CODEL
SO2 CO NO
Suitable for measuring many different species
wavenumber = 1/wavelength in cm = 10000/wavelength in μm
H2OH2O and CO2
Infrared spectroscopy
CODEL
SO2 CO2 CO NO
Suitable for measuring many different species
wavenumber = 1/wavelength in cm = 10000/wavelength in μm
H2OH2O and CO2
Infrared spectroscopy
CODEL
SO2 CO2 CO NO
Suitable for measuring many different species
wavenumber = 1/wavelength in cm = 10000/wavelength in μm
CH4
H2OH2O and CO2
Infrared spectroscopy
CODEL
HCl SO2 CO2 CO NO
Suitable for measuring many different species
wavenumber = 1/wavelength in cm = 10000/wavelength in μm
CH4
H2OH2O and CO2
Infrared spectroscopy
CODEL
CH4NO2 HCl SO2 CO2 CO NO
Suitable for measuring many different species
wavenumber = 1/wavelength in cm = 10000/wavelength in μm
H2OH2O and CO2
Carbon Monoxide CO
CODELwavenumber = 1/wavelength in cm = 10000/wavelength in μm
Live and Reference measurements
• Particles in the gas
• Variations in the transmitted energy
• Contaminated optical surfaces
CODEL
It is necessary to separate the infrared energy absorbed by the measured gas from the energy modified by other effects such as:
Multiple measurements in a single analyser
infrared detector
Pairs of live and reference optical filters are positioned sequentially in front of the detector
Multiple measurements in a single analyser
infrared detector
Pairs of live and reference optical filters are positioned sequentially in front of the detector
Multiple measurements in a single analyser
infrared detector
Pairs of live and reference optical filters are positioned sequentially in front of the detector
Multiple measurements in a single analyser
infrared detector
Pairs of live and reference optical filters are positioned sequentially in front of the detector
Application of IR spectroscopy
• Conventional cold extractive
• Conventional hot extractive
• Extractive with permeation dryer
• Open path cross-duct
• In-situ diffusion probe
• Heavy duty hot extractive
CODEL
Conventional cold extractiveSimple probe with pre-filtersCondensate removed
at probeSimple sample linesx Some gases are absorbed
in the condensatex Long sample lines can freezex Major maintenance required
if any water or solids reach the delicate analysers
CODEL
CO
NO
NO2
Dryers & filters
SO2
Condensate drain
Free-standing analyser cabinet in control room
Conventional hot extractiveHeated probe with pre-filtersGases held above dewpoint
in heated sample line Analyser cabinet must be
in control room with long expensive sample lines
Major maintenance required if heated sample lines fail and any water or solids reach the delicate analysers
CODEL
CO
NO
NO2
Final filters
SO2
Free-standing analyser cabinet in control room
Extractive with permeation dryerProbe with pre-filter and
integral permeation dryerWater vapour removed
at probeSimple sample lines Requires clean compressed
air dried to -20degC Major maintenance if water or
solids reach the analysers No water vapour measurement
for normalisationCODEL
CO
NO
NO2
Final filters
SO2
Dry air in
Wet air out
Tx Rx
Open path cross-ductSimple installationNo corruption of gasesSingle or multiple species Performance cannot be
audited against test gases Performance depends on
available measurement path Variations in dust level and optical
alignment can limit measurement sensitivity
CODEL
TxRx
CODEL in-situ diffusion probeFiltered measurement chamber
suitable for high dust levelsSimple installationNo corruption of gasesSingle or multiple species
plus H2OPerformance can be audited
against test gasesFixed optical alignmentMaximum reliability
CODEL
CODEL
CODEL G-CEM4000 gas analyser
CODEL heavy duty hot extractive In-duct probe with pre-filterGases held above dewpoint
in heated sample lineMultiple species plus H2O
Performance can be audited against test gases
Robust folded beam analyser requires minimal pre-conditioning
Increased measurement sensitivityMaximum reliability CODEL
Free-standing field-mounted analyser
CODEL G-CEM4100 gas analyser
Particulate measurement
Particles emitted from a combustion process include smoke, soot, ash & carried-over process materials (such as cement).
All of these particles are visible. They can be measured by looking at how much they absorb and scatter visible light.
CODEL
Particulate legislation
• Ringelmann number
• Opacity
• Smoke density
• Extinction
• Dust density in mg/m3
Requirements for expressing the amount of solids emitted from a process can vary dramatically for different processes and in different countries
CODEL
RingelmannA simple manual assessment of the appearance
of the plume against a standard chart graded white to black in 6 steps (Ringelmann 0 – 5)
CODEL
Continuous measurementsFor continuous measurement the energy
absorbed and scattered by the particles inside the exhaust duct can be expressed as:
Transmittance T = Ir/Io
Transmitted energy Io
Received energy Ir
CODEL
Opacity/Smoke densityThis is the simplest continuous measurement.
It is the opposite of transmittance expressed as a percentage. %opacity = (1-T)x100
This is the measurement preferred by US EPA
Transmitted energy Io
Received energy Ir
CODEL
Opacity
With a uniform dust concentration the opacity measured depends on the measured path.
CODEL
% opacity
% opacity
% opacity
Continuous dust monitoring techniques
CODEL
• Single pass transmissometer
• Double pass transmissometer
• Double beam transmissometer
• Optical scatter
• Triboelectric probe
Single pass transmissometer
Simple low cost techniqueHigh efficiency air purges to keep windows clean Cannot differentiate between gas-borne particles
and window contamination Cannot detect misalignment errors
CODEL
Beam splitter
Light source
Control detector
Measurement detector
Double pass transmissometer
CODEL
Auto-collimating
reflectorLight source
Detector
Zero point reflector
Air purges to keep windows cleanZero check reflector in transceiver unit Window contamination check on transceiver only Non-linear due to back scatter from the particles Cannot detect misalignment errors
Mirror
Double beam transmissometer - measuring
CODEL
High efficiency air purges keep windows cleanAlternate, bi-directional measurement provides
automatic misalignment checkMeasures across entire duct section
Rotary valve with integral mirror
Light source Detector
Mirror Beam splitter
Double beam transmissometer - contamination check
CODEL
Protected mirrors check individual contamination on both transceivers
Rotary valves protect transceivers during purge air or power failure
Mirror rotated into optical path
Light source Detector
Mirror Beam splitter
Light source
Detector
Back, forward or side scatter
CODEL
High sensitivityCan be built into a probe Measures in a very small
zone – local to duct wall Measured zone not
consistently representative In-duct reflections cause zero errors Unsuitable for large ducts or high levels
Measures light reflected from illuminated particles
Triboelectric probe
CODEL
Simple low cost probeHigh sensitivityEasy to install Highly cross-sensitive to
many operating parameters Measurement is flow-dependent Unsuitable for large ducts
Measures electrical charge transfer as particles collide with the probe
Hot gas velocity measurement techniques
CODEL
• Pitot tube
• Thermal anemometer
• Bi-directional ultrasonic
• Triboelectric correlation
• Infrared correlation
Pitot tube
CODEL
Simple manual techniqueSingle or multi-point Automated systems are
prone to blockage Unsuitable for irregular,
cyclonic or angular flow Unsuitable with high level
particulates or aerosols Complex installation
Type ‘L’ Pitot tube
Differential pressureVelocity
pressure
Static pressure
Measures the velocity pressure produced at an orifice facing into the flow.
Thermal anemometer
CODEL
Flue gases cool a hot wire held in the gas stream. The amount of cooling is a function of the gas temperature, gas composition and velocity.
Simple installationSingle or multi-point Unsuitable for ducts with
high spatial variations Affected by condensates
and dust build-up Non-linear outputs need site
calibration
Bi-directional ultrasonic
CODEL
Measures the difference between the transit time of sonic pulses transmitted upstream and downstream Average measurement across
entire duct Transceivers must be purged
to keep them cool and clean Complex install and service
– especially on large ducts Complex end effects Errors due to secondary
reflections and vibration
Correlation velocity measurement
CODEL
Measures the offset (equal to the transit time T) between signals from 2 separated detectors.
time
Τ Τ
Triboelectric correlation
CODEL
Measures the transit time between signals from two close-coupled triboelectric probes
Simple installation Unsuitable for ducts with high
spatial variations Affected by condensates
and dust build-up Unsuitable for turbulent flow Unsuitable for large ducts Close-coupled probes prone to
bridging with high dust burdens
Infrared correlation
CODEL
Measures the transit time between signals from two separated bulk infrared detectors
Simple installationAverage across entire ductSuitable for high temperatures High efficiency air purgesUnaffected by condensates
and dust build-upSuitable for turbulent flowSuitable for large or small ducts
CODEL
CODEL V-CEM 5000 flow monitor
Data normalisation
CODEL
• Changes in temperature • Changes in absolute pressure• Excess air• Water vapour
International legislation demands that any dilution at the point of measurement must be corrected. The measurement can be diluted by:
It is necessary to measure these complementary parameters and apply the appropriate correction. This is known as normalisation. Normalised values are in mg/Nm3
Data formats
CODEL
Gases• ppm• mg/m3
• mg/Nm3
• kg/hr
With the necessary complementary measurements CODEL analysers can present data in the following formats to suit all legislative and plant requirements
Particulates• opacity• extinction• mg/m3
• mg/Nm3
• kg/hr
System integrationIn any CEM system it is vital that normalisation and operating data are shared by all analysers.
CODEL analysers are designed to communicate with each other using a series of robust bi-directional data highways.
One highway distributes data between all analysers on the same stack. Another highway can be connected to a remote station for central data & diagnostic presentation and control via a PC.
This central PC can be interrogated and controlled via a telephone modem or broadband internet link.
CODEL
Typical CODEL SmartCEM layout
CODEL
Typical CODEL SmartCEM layout
CODEL SmartCEM data loggingMeasured and normalised data in many formats
CODEL
• Real time values • All data formats• Digital & analogue
presentation• Normalisation data• User-configurable
spans & alarms• Up to 12 channels in
up to 12 groups
CODEL
CODEL SmartCEM data loggingHistorical data in many formats
• Instant access to >5yrs historical data
• Customised reports• 3 levels of security• User-configurable
spans and alarms• Multi-user networking• System diagnostics• QAL3 reporting
CODEL
Total Solutions - Total Confidence
CODEL International LtdStation Road, Bakewell,Derbyshire DE45 1GEEnglandTel : +44 (0) 1629 814 351Fax : +44 (0) 8700 566 307e-mail : [email protected] : www.codel.co.uk