أجهـــزة الرصـــــد والمراقبــة emission monitoring equipment

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أجهـــزة الرصـــــد

والمراقبــة

Emission Monitoring Equipment

مهندس / ماهــر عـزيــز استشارى الطاقة والبيئة وتغير المناخ

9795-368-0122( 2)موبايل : < : اليكترونى <[email protected]بريد

العربية الدول جامعةالعرب الوزارء لمجلس الفنية واألمانة للكهرباء العربى الوزارى المجلس أمانة

البيئة - شئون عن المسئولينكهرماء ) ( والماء للكهرباء القطرية العامة الموسسة

آسيا ) لغربى واالجتماعية االقتصادية ( ESCWAاللجنةللبيئة ) المتحدة األمم (UNEPبرنامج

التدريبية طرق حول " الدورة فى األساسية المبادئالعربية " الدول فى الكهرباء بقطاع للبيئة الملوثة االبتعاثات حساب

الدوحة – / قطر 2012مايو 31- 29دولة

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Air Quality Continuous Emission

Monitoring for Power Station

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GENERAL

• The Erection of New Power Stations requires the assessment

of the Environmental Impact of the said power station on the

Surrounding Environment

• The assessment requires the Real Time Continuous Air Quality

Monitoring of the main criteria air pollutants

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GENERAL (Contd.)

• The Main Criteria Air Pollutants are:

o SO2

o NO, NO2, NOx

o CO

o PM-10 & TSP

Wind Direction, Wind Speed, Sigma Theta, and Temperature

are also measured on a Real Time basis

• The Air Quality Measurements Starts one year before firing

and one year after firing.4

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GENERAL (Contd.)

• After firing; it is mandatory to have Continuous

Emission Monitoring CEMS for each stack

• The CEMS are intended to measure source

pollution and not Ambient Air Quality

Monitoring.

• The type of analyzers used for the Continuous

Emission Monitoring have higher ranges than

those used for Ambient Air Quality because of

the higher concentrations that are measured.5

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GENERAL (Contd.)

• There are different internationally approved methodologies used

for conducting these measurements

• Air Quality Monitoring:

− Chemiluminescence• NO, NO2, NOx, NH3 Gas Analysis

− Pulsed Fluorescence

• SO2 and H2S Gas Analysis

− Non destructive IR Gas filter wheel correlation• CO so also CO2and HCL Gas Analysis

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GENERAL (Contd.)

– UV absorption

• O3 Gas Analysis

– Flame ionization detection

• Methane, Non-Methane and Total

Hydrocarbons Gas Analysis

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Main components of an Ambient air quality monitoring system:

• Gas analyzers

• Air Sample Intake and Sample Manifold

• Particulate monitors

• Meteorological sensors

• Data acquisition/logger and software

• Calibration system

• Environmentally Controlled shelter

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Measurement Principles

1. Nitrogen Oxides (NO-NO2 – NOx)

Chemiluminescence Principle:

• This method depends on the principle that nitric oxide

(NO) and ozone (O3) react to produce a characteristic

luminescence with intensity that is linearly proportional to

the NO concentration. Infrared light emission results when

electronically excited NO2 molecules decay to lower

energy states.

NO + O3 → NO2 + O2+ hv

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Measurement Principles (Contd.)

• Specifically, Nitrogen dioxide (NO2) must first be

transformed into NO before it can be measured using the

chemiluminescent reaction. NO2 is converted to NO by a

molybdenum NO2-to-NO converter heated to about 325 °C.

• An ozonator is used to generate the ozone needed for the

chemiluminescent reaction. At the reaction chamber, the

ozone reacts with the NO in the sample to produce excited

NO2 molecules. A photomultiplier tube (PMT) housed in a

thermoelectric cooler detects the luminescence generated

during this reaction.10

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• In the (NO mode) the sample routes directly to

the reaction chamber as shown in Figure-1 and

the output of the reaction represent the NO

concentration in the sample.

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• In the (NOx mode) the sample routes through the

NO2-to-NO converter and then to the reaction

chamber and the output of the reaction

represents the NOx concentration in the sample.

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• The difference between the concentrations "NOx mode"

and the "NO mode" is used to calculate the NO2

concentration. The analyzer outputs NO, NO2, and NOx

concentrations.

• Typical NO - NO2 – NOx analyzer using

Chemiluminescence

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2. Carbon Monoxide & Dioxide CO & CO2Gas Filter Correlation using Non-Destructive Infrared (NDIR) Principle:

• This method uses a variation of infrared (IR) absorbance

spectroscopy. With this technique, the concentration of

individual pollutants in the sample is measured based on

that compound’s capacity to absorb infrared energy of a

specific wavelength. It uses band-pass optical filters rather

than a diffraction grating or prism to create an IR beam

with a limited range of wavelengths.

• CO and CO2 have an IR spectrum with a fine structure.

This allows them to be used in a gas cuvette as a specific

and highly selective optical filter to sensitize the analyzer

to just that gas.

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2. Carbon Monoxide & Dioxide CO & CO2Gas Filter Correlation using Non-Destructive Infrared (NDIR) Principle (Contd.):

• Gas Filter Correlation is based on a differential measurement between

the transmissions of two beams of light. Light is passed through a

sample gas first via a measure gas filter containing nitrogen and then

via a reference gas filter containing the target gas.

• When the target gas filter is in the beam, IR energy is pre-absorbed at

only the target gas wavelengths. With a measurement sample

containing the target gas in the cell, most of the energy at the specific

target wavelengths has already been absorbed, so little extra

absorption can occur. This gives an almost unchanged signal at the

detector.

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Sample cell

IR Source

Detector

Filter wheelwith gas filters

Target gasfilter

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• When the nitrogen filter is in the beam, no IR energy is

pre-absorbed. The signals for the two filters are balanced

electrically. With a measurement sample containing the

target gas in the cell, absorption occurs at the specific

target wavelengths. The reference signal at the detector is

strongly reduced.

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2121

Sample cell

IR Source

Detector

Filter wheelwith gas filters

Nitrogenfilter

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• The resulting difference between signals produces a very

sensitive measurement output for the target gas. Potential

cross-interfering gases do not match up exactly to the

target gas fine structure, and therefore cause equal

reduction in both gas and nitrogen signals. Optical

degradation also causes equal losses.

• Since the signals are reduced equally there is no

difference and therefore no interference and no optical

effects.

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3. Sulfur Dioxides (SO2)

Fluorescence Principle:

• This method operates on the principle that SO2 molecules

absorb ultraviolet (UV) light and become excited at one

wavelength, then decay to a lower energy state emitting

UV light at a different wavelength.

SO2 + hv1 → SO2* → SO2 + hv2

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3. Sulfur Dioxides (SO2) (Contd.)

• The sample is drawn into the analyzer through the sample

bulkhead. The sample flows into the fluorescence chamber, where

pulsating UV light excites the SO2 molecules. The condensing lens

focuses the pulsating UV light into the mirror assembly. The mirror

assembly contains four selective mirrors that reflect only the

wavelengths which excite SO2 molecules.

• As the excited SO2 molecules decay to lower energy states, they

emit UV light that is proportional to the SO2 concentration. The

band pass filter allows only the wavelengths emitted by the excited

SO2 molecules to reach the photomultiplier tube (PMT). The PMT

detects the UV light emission from the decaying SO2 molecules.

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Typical SO2 analyzer using fluorescence principle is shown:

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4. Particulates (PM-10 & TSP)

Beta Ray Attenuation Principle

• On-line Particulate Monitor uses the beta attenuation

principle for measuring the growing particle mass during

sampling. This mode of operation permits a real time

measurement and an on-line output of the mass

concentration of the suspended particulate in ambient air.

• Due to this process very high measurement stability is

achieved. The air mass change in the active volume by

temperature and pressure is corrected.

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4. Particulates (PM-10 & TSP) (Contd.)

• A new section of the filter tape moves into the measuring

position (2). Ambient air is sucked through the inlet and the

sample tube. The airborne dust particles are deposited on the

filter.

• A single filter spot principle is used. This single filter spot

remains in the "chamber for particulate collection and

measurement" (2) until it is full loaded (typ. 1500 μg) Then the

full filter section moves out and a fresh filter section moves in

the measuring position (automatic filter change).

• A new cycle starts with an automatic zero adjustment of the

mass signal.

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• The „chamber for particulate collection and measurement“ (2)

and the filter is located between source (4) and detector (1). The

beta rays pass through the filter and the accumulated dust layer.

The intensity of the beta rays is attenuated with increasing dust

mass load, leading to a decreasing count rate R from the

detector. From the current count rate the filter load is calculated.

• During dust sampling (2), an increasing number of particles are

deposited. This dustlayer is growing up continuously. At any time

the signal output display the sampled mass on the filter spot.

This system is a so-called "direct observer" of the dust mass at

point (2).

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• All the time the mass value (in μg) on the filter spot is known, and

the speed the particle sampling is observed. The detector is also

sensitive for the natural alpha- and beta activity, which is absorbed

in the particles. This additional count rate results in an error of the

particulate mass determination.

• This error may be (in C-14 devices) as high as actual dust

concentration, especially after filter change or when the natural

activity concentration changes.

• The FH 62C14 has implemented a procedure to determine

separately the natural activity on the filter and to eliminate this

error. A compensated mass signal is the result.

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• From the temporal increase of the dust mass and the measured air

flow rate, the particulate mass concentration is calculated and

displayed.

• Using size-selective inlets (PM-10, cyclone, PM-2.5) the flow rate

has to be constant for preventing a cutpoint shift. Therefore a

RPM-regulated vacuum pump is used. The rotating speed is

controlled by the FH62C14 to keep the air flow rate constant.

• The influence of humidity in ambient and the danger of water

condensation in the sampling tube can be prevented using the

suction tube heater. This possible influence is only important to

consider at high humidity in the summer or at foggy days

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Gas Analyzers

• Main Advantages of the Gas Analyzers Used :

o High selectivity/negligible interference’s

o High accuracy/sensitivity

o Long term stability

o Minimal Consumables

o Easily Maintained

o Wide range of I/O available• Analog Outputs• Digital Inputs• Status Relays

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Particulate Monitors

• Methodologies used to measure TSP, PM10,

PM2.5, PM1:

o β-ray attenuation

o Oscillating micro balances

o Old Gravimetric technique

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β-ray attenuation

• Main Features& Advantages:

o Most Commonly Used

o Real-time, Continuous; measuring during sampling

o Low detection limit, high accuracy, and good resolution

o Automatic zero adjustment

o Accurate mechanical operation

o Volumetric air flow rate at the inlet with volumetric or

standard conditions concentration data output

o Processor controlled calibration of all sensors

o Detector Life ~10 years

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Meteorological Sensors

• The Meteorological Weather Parameters Measured

For Air Quality Applications are:

o Wind speed

o Wind direction

o Ambient temperature

o Relative humidity

o Barometric pressure

o Precipitation

o Solar & Net radiation

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Data acquisition/logger and software

• The Data Logger Consists of Data Storage &

Control Modules:

o Analog input modules

o Digital input modules

o Relay output modules

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Data acquisition/logger and Software Station

• Station Manager software that Provides a full interface of

the station: o Data display & processing

o Manual Calibration

o Automatic zero/span checks

o Power failures log

o Station Visit Log

• The Control System for the EMC Station Manager is the

EMC System Manager software that provides full interface

between different stations:

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Data acquisition/logger and Software Station

• The Control System for the

EMC Station Manager is

the EMC System Manager

software that provides full

interface between different

stations:

o Manual/Automatic data

polling

o Data display & processing

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Data acquisition/logger and software

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Calibration System

• Any Gas analyzer needs at least 2 point calibration to

linearize it’s response.

• The main components of a calibration system:

o Zero air generator

o Dynamic Gas calibrator

o Standard gas cylinders

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Environmental Controlled Shelter

• The shelter is designed to

have the following features :o Fixed or Mobile (mounted on a

trailer) depending on the required

application

o Air Sampling manifold and Intake

assembly

o Efficient thermal insulation

suitable for local weather

conditions

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Environmental Controlled Shelter

o Automatic fire fighting system

with two smoke detector types

o Instrument rack mounts for

easy handling

o Properly sized air conditioning

units

o Electric Power Supply

stabilization

o In shelter temperature

monitoring

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Continuous Emissions Monitoring Systems (CEMS)

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CEMS Basic Types

Cross StackIn Stack

• In-situ Monitoring

Chiller Others

• Extractive

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In-situ Monitoring: Cross Stack

• Opacity Monitoring

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In-situ Monitoring: In Stack

• Zirconia

• O2

• Catalytic Sensor

• Combustibles (COe –Carbon

monoxide equivalent)

• Laser diode spectroscopy

• CO, CO2, CO (low conc.) , CO2

(low conc.), O2, HCL, H2S, HF,

NO, N2O, H2O, NH3, HCN, CH4,

C2H2, C3H6, CH3l, CH3OH

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Extractive: Chiller System Main Features

Suitable for most applications

Suitable for a wide variety of pollutants

Especially good for saturated conditions

Dry Basis Measurement

Cannot be used to measure water soluble

components such as NH3

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Extractive: Flow Diagram Chiller System

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Extractive: Main Components Chiller System

• Sample conditioning system

• Gas analyzers

• Data logger and software

• Calibration system

• Environmental Controlled shelter

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Extractive: Sampling System Chiller System

• Sampling probe

• Heated sample

line

• Filters

• Cooler

• Pump

• Flow meters

• Pressure

regulators49

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Extractive: Gas Analyzers Chiller System

• Paramagnetic

o O2

• Infrared Gas Filter Correlation

(GFC)

o CO, SO2, NO.

• Infrared Single Beam Single

Wavelength (SBSW)

o CO2

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Extractive: Gas Analyzers Chiller System (Contd.)

• Non-Destructive Infrared

(NDIR)

o CO, SO2, NO, NO2, CO2

• Chemiluminesence

o NO, NO2, NOx..

• Flame ionization detection

o Methane, Non-Methane

and Total Hydrocarbons

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Extractive: Data Logger and Software Chiller System

• The Data logger offers data

storage and control modules:

o Analog input modules

o Digital input modules

o Relay output modules

• Can be Easily integrated with

Allen-Bradely-Like PLCs

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• The Station manager

software offers a full

interface of the station:o Complies with 40 CFR Part 60 and

40 CFR Part 75


o Manual Calibration

o Automatic zero/span checks

o Power failures log

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Extractive: Data Logger and Software Chiller System (Contd.)

• The System manager

software offers a full

interface between different

stations:

o Manual/Automatic data polling


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Extractive: Calibration System Chiller System

• NIST traceable Standard

Gases

• Supplied complete with dual

stage pressure regulators for

accurate controlling of gas

output

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Extractive: Environmentally Controlled Shelter• The shelter is designed to have the

following features:o Efficient thermal insulation suitable for

local weather conditions

o Automatic fire fighting system with two

smoke detector types

o Instrument rack mounts for easy

handling

o properly sized air conditioning units

o Electric Power Supply stabilization

o In shelter temperature monitoring

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Ambient Air Quality Monitoring Stations

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Ambient Air Quality Monitoring Station

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Ambient Air Quality Monitoring Station

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THANK YOU61

أجهـــزة الرصـــــد والمراقبــة emission monitoring equipment

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