Viktória B. Kovács| Pollutant formation | © 2015 BMEGEENAG51 | D218 | 2015-16-1 | 1 EMISSION...


EMISSION MEASUREMENT

Harmful components Emission measuring systems

– In-situ: (in-stack, cross-stack) measurement– Ex-situ: extractive measurement: „analyzers with a

measuring probe” Requirements of analyzers Reference methods: Analyzers at D.E.E

– NDIR (CO, CO2, CH4, ….) Servomex 1400B4 SPX O2/CO2

Thermo 48C CO

– (H)CLD (NO, NOx,) Thermo 42C NO-NO2-NOx

– FID (THC, CxHy, VOC) Bernath Atomic Modell 9900 THC

– PMD (O2) Servomex 1400B4 SPX O2/CO2

Measuring Cell Chromatography Older techniques


HARMFUL COMPONENTS OF FLUE GAS CO2: GHG CO: poisonous (suffocating from ~700ppm) THC (VOC, PAH)

– depends on molecule: – Methane: GHG, but PAH carcinogenic, etc.

NOx: acid rain SOx: acid rain (Dioxin, furans: teratogenic, mutagenic)


IN-SITU MEASUREMENT

NOx reduction with SCR_SICK.mp4:https://www.youtube.com/watch?v=pxiRC44tN70

Optic grid

UV detector

UV transmitter lamp

Condenser lens

mirror lens

windowMeasuring

section

Triple reflector

mirror

Beam splitting mirror

Evaluation unit Measuring unit

Advantages– Direct and immediate measurement in

process– Non-contact measurement: suitable for

aggressive or corrosive gases– Very short response time– Very low maintenance requirements

Disadvantages– More expensive– Simultaneously measurement of more

component is critical– Humidity causes problems


EX-SITU MEASURMENT

Advantages– For applications with high dust concentration– Measurement is possible far from the emission source– More components can be measured simultaneously– Low concentration is measurable– Suitable for difficult measurement tasks

Disadvantages– More units– High response time– Corrosion risks– Condensation risk– Soot deposit („pipe remembers”)

P

E le m z õ kM in ta e lõ k é sz ítõ

h ű tőM in ta

K a lib rá ló g á z o k

F ű tö tt m in ta v e v ő

Analyzers

Standard gases

heated pipe

Sample

Sample conditioning

system


REQUIREMENTS OF ANALYZERS

1. Physical working principle2. Fast (reaction time under sec.)3. Stable in time4. High sensitivity5. High selectivity6. Low inter-sensitivity7. Linear characteristic8. Independent from ambient condition9. Protected from ambient 10. Cheap


IR SPECTROSCOPY

deals with the infrared region of the electromagnetic spectrum

it can be used to identify and study chemicals molecules absorb specific frequencies that are

characteristic of their structure the frequency of the absorbed radiation matches the

transition energy of the bond or group that vibrates passing a beam of IR light through the sample: when

the frequency of the IR is the same as the vibrational frequency of a bond, absorption occurs

λ: 780 nm –1000 μm (f: 300 GHz – 384 THz) IR_1.avi:https://www.youtube.com/watch?v=DDTIJgIh86E


VIBRATION OF CH2 IN A CH2X2 GROUP

Symmetricalstretching

Antisymmetricalstretching Scissoring

Rocking Wagging Twisting


NDIR (NON-DISPERSIVE INFRARED ABSORPTION)

http://www.tsi.com/iaq/appnote/ndir_co2.shtmlNDIR.avi:https://www.youtube.com/watch?v=a2dEYmW0xys



http://www.signalinstruments.com


NDIR (NON-DISPERSIVE INFRARED ABSORPTION)IR SPECTRUM

http://www.mdpi.com/1424-8220/13/6/7079/htm


NDIR – CO2

IR_3.avi:https://www.youtube.com/watch?v=FR9DFkenWUU

http://www.raesystems.com


FTIR - FURIER TRANSFORMED IR SPECTROSCOPY measurement technique that allows one to record

IR spectra Infrared light is guided through an interferometer

and then through the sample (or vice versa). A moving mirror inside the apparatus alters the

distribution of infrared light that passes through the interferometer.

The signal directly recorded, called an "interferogram", represents light output as a function of mirror position.

A data-processing technique called Fourier transform turns this raw data into the desired result (the sample's spectrum): Light output as a function of infrared wavelength (or equivalently, wavenumber).

The sample's spectrum is always compared to a reference.


NDIR/ FTIR COMPARISONGas Filter Correlation IR Narrow frequency range defined

by the filter One filter for one component More component more filter More filters more calibrations

Fourier Transform Infrared (FTIR)• "Fellgett's advantage" or the "multiplex advantage„

– information at all frequencies is collected simultaneously– improving both speed and signal-to-noise ratio

• "Jacquinot's Throughput Advantage„ - higher light levels • Better wavelength accuracy• Lower stray light sensitivity• More components are observable simultaneously

IR_2.avihttps://www.youtube.com/watch?v=DDTIJgIh86E

Kertész Károly: Folyamatos gázelemzés


THERMO 48C CO ANALYZER (D.E.E.) GFC IR

http://www.ierents.com/Spec%20Pages/Thermo%2048C%20CO.pdf


CHEMILUMINESCENCE

Nitric oxide (NO) and ozone (O3) react to produce a characteristic luminescence with an intensity linearly proportional to the NO concentration.

NO+O3 → (1-n)·NO2+ n·NO2*+O2

IR light emission results when excited NO2 molecules decay to lower energy states.

NO2* → NO2+ hv Nitrogen dioxide (NO2) must be first

transformed into NO before it can be measured with chemiluminescent method.


CLD (CHEMILUMINESCENT DETECTOR)

Principle: NO+O3→NO2*+O2

www.emersonprocess.comChemiluminescence magic.mp4:https://www.youtube.com/watch?v=8_82cNtZSQE


THERMO 42C NO-NO2-NOX ANALYZER (D.E.E.)CLD

Converter - efficiency depends on temperature: molybdenum heated to approximately

325°C- consists of an insulated housing, heater, replaceable cartridge, and a type K

thermocouple

NO+O3→NO2*+O2 http://www.thermo.com.cn/Resources/200802/productPDF_20998.pdf


FID - FLAME IONISATION DETECTOR

In a flame, oxygen and hydrogen are burned.

When in a hydrogen flame other molecules pass, these will burn also and increase the amount of ions.

The ions generated by the flame are attracted to the positive side of an electrical field in the detector cell.

The electrical current in the detector cell changes, this change is measured and has a direct correlation with the concentration.


FID- FLAME IONISATION DETECTORCH + O CHO+ +

e-

- Measurable current : 10-12A - Without sample: 10-14A - Detector response~ measurable

*107

- Sensitivity 10-2 compared to TCDFid.swfhttp://www.chromedia.org/dchro/swf/ZsxnjdeIW.swf


FID - FLAME IONIZATION DETECTOR

CH + O CHO+ + e-


PMD (PARAMAGNETIC DETECTOR) Oxygen is attracted into a strong magnetic field. Most other

gases are not. A focused magnetic field is created. Any oxygen that is

present will be attracted into the strongest part of the magnetic field.

Two nitrogen filled glass spheres are mounted on a rotating suspension within a magnetic field.

A mirror is mounted centrally on the suspension. Light is shone onto the mirror. The reflected light is directed onto a pair of photocells. Oxygen attracted into the magnetic field will displace the nitrogen filled spheres, causing the suspension to rotate. The photocells will detect the movement and generate a signal.

The signal generated by the photocells is passed to a feedback system. The feedback system will pass a current around a wire mounted on the suspension. This causes a motor effect, which will keep the suspension in its original position. The current measured flowing around the wire will be directly proportional to the concentration of oxygen within the gas mixture.


PMD (PARAMAGNETIC DETECTOR)


PMD (PARAMAGNETIC DETECTOR)

www.fic-net.co.jp

O2 +100 Nitrogen -0.42

Air +21 (száraz)

Chlorine -0.13

CO2 -0.61 Hydrogen -0.12

Argon -0.58 Acetylene

-0.38

Ammonia

-0.58 N2O -0.58

Ethane -0.83 NO +43.8

Methane -0.37 NO2 +28.0

Cross contamination


ALTERNATIVE O2 MEASUREMENT:ELECTROCHEMICAL METHOD

Oxygen Sensor.avi:https://www.youtube.com/watch?v=Fl3aD1qJrEg&list=UUycARi6zsqrcC0M90gdve5A

1- air; 2- exhaust gas; 3- sensor; 4- electrolyte (zirconium dioxide);

5- exhaust side; 6-reference side; 7- span


MEASURING CELL TESTO 350

CO SO2 NO NO2 H2S

CO 100 65 30 -60 340

SO2 2 100 0 -100

200

NO 0 5 100 15 18

NO2 -1 -5 5 100 20

H2S 7 20 0 -20 100

Cross contamination

I

D iffu z ió s g á tM érő e lek tró d (an ó d )

E lek tro lit

D iffu z ió s g á tM érő e lek tró d (k a tó d )

M in ta

2 H +

2 e -

2 e -

C O 2

1 /2 O 2

C O

R efe re n c ia g á z

sample gas

reference gas

diffusion barrier

diffusion barrier

electrolyte

Probe (anode)

Probe (cathode)

–SO2 activated carbon, gold

- CO, platinum

–platinum


GAS CHROMATOGRAPHY

GC Columns.avi:https://www.youtube.com/watch?v=q0pM-k0SvOQ

http://web.mit.edu/12.000/www/finalpresentation/experiments/gcms.html


CHROMATOGRAM


QUESTIONS

What are the harmful components of exhaust gas? Why are they harmful?

Describe cross-stack measuring technique! (advantages, disadvantages)

Describe extractive measuring technique! (advantages, disadvantages)

What are the requirements of analyzers? Describe NDIR! (working principle, detected

components) Describe CLD! (working principle, detected

components) Describe FID! (working principle, detected

components) Describe PMD! (working principle, detected

components)


THANK YOU FOR YOUR ATTENTION!

Viktória Barbara KOVÁCS

Build. D room 207B06 1 463 2592

[email protected]

Viktória B. Kovács| Pollutant formation | © 2015 BMEGEENAG51 | D218 | 2015-16-1 | 1 EMISSION...

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Transcript of Viktória B. Kovács| Pollutant formation | © 2015 BMEGEENAG51 | D218 | 2015-16-1 | 1 EMISSION...