أجهـــزة الرصـــــد والمراقبــة Emission Monitoring Equipment جامعة الدول العربية أمانة المجلس الوزارى العربى للكهرباء والأمانة الفنية لمجلس الوزارء العرب المسئولين عن شئون البيئة - الموسسة العامة القطرية للكهرباء والماء ( كهرماء ) اللجنة الاقتصادية والاجتماعية لغربى آسيا ( ESCWA ) برنامج الأمم المتحدة للبيئة ( UNEP ) الدورة التدريبية حول " المبادئ الأساسية فى طرق حساب الابتعاثات الملوثة للبيئة بقطاع الكهرباء فى الدول العربية " دولة قطر – الدوحة / مايو

2 2 Air Quality Continuous Emission Monitoring for Power Station 2 2

3 3 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 3 3

4 4 GENERAL (Contd.) The Main Criteria Air Pollutants are: o SO 2 o NO, NO 2, NO x 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 4

5 5 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 5

6 6 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 SO 2 and H 2 S Gas Analysis − Non destructive IR Gas filter wheel correlation CO so also CO2and HCL Gas Analysis 6 6

7 7 GENERAL (Contd.) – UV absorption O3 Gas Analysis – Flame ionization detection Methane, Non-Methane and Total Hydrocarbons Gas Analysis 7 7

8 8 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 8 8

9 9 Measurement Principles 1. Nitrogen Oxides (NO-NO 2 – 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 + O 3 → NO 2 + O 2 + hv 9 9

10 Measurement Principles (Contd.) Specifically, Nitrogen dioxide (NO 2 ) must first be transformed into NO before it can be measured using the chemiluminescent reaction. NO2 is converted to NO by a molybdenum NO 2 -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

11 Measurement Principles (Contd.) 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. 11

12

13 Measurement Principles (Contd.) 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. 13

14

15 Measurement Principles (Contd.) The difference between the concentrations "NOx mode" and the "NO mode" is used to calculate the NO 2 concentration. The analyzer outputs NO, NO 2, and NOx concentrations. Typical NO - NO 2 – NOx analyzer using Chemiluminescence 15

16

17 2.Carbon Monoxide & Dioxide CO & CO2 Gas 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 CO 2 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. 17

18 2.Carbon Monoxide & Dioxide CO & CO2 Gas 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. 18

19 2.Carbon Monoxide & Dioxide CO & CO2 Gas Filter Correlation using Non-Destructive Infrared (NDIR) Principle (Contd.) : 19 Sample cell IR Source Detector Filter wheel with gas filters Target gas filter

20 2.Carbon Monoxide & Dioxide CO & CO2 Gas Filter Correlation using Non-Destructive Infrared (NDIR) Principle (Contd.) : 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. 20

21 Sample cell IR Source Detector Filter wheel with gas filters Nitrogen filter

22 2.Carbon Monoxide & Dioxide CO & CO2 Gas Filter Correlation using Non-Destructive Infrared (NDIR) Principle (Contd.) : 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. 22

23 3.Sulfur Dioxides (SO 2 )  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. SO 2 + hv 1 → SO 2 * → SO 2 + hv 2 23

24 3.Sulfur Dioxides (SO 2 ) (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. 24

25 Typical SO 2 analyzer using fluorescence principle is shown: 25

26 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. 26

27 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 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. 27

28 4.Particulates (PM-10 & TSP) (Contd.) 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). 28

29 4.Particulates (PM-10 & TSP) (Contd.) 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. 29

30 4.Particulates (PM-10 & TSP) (Contd.) 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 30

31 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 31

32 Particulate Monitors Methodologies used to measure TSP, PM10, PM2.5, PM1: o β-ray attenuation o Oscillating micro balances o Old Gravimetric technique 32

33 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 33

34 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 34

35 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 35

36 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: 36

37 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 37

38 Data acquisition/logger and software 38

39 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 39

40 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 40

41 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 41

42 Continuous Emissions Monitoring Systems (CEMS) 42

43 CEMS Basic Types Cross Stack In Stack In-situ Monitoring Chiller Others Extractive 43

44 In-situ Monitoring: Cross Stack Opacity Monitoring 44

45 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 45

46 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 46

47 Extractive: Flow Diagram Chiller System 47

48 Extractive: Main Components Chiller System Sample conditioning system Gas analyzers Data logger and software Calibration system Environmental Controlled shelter 48

49 Extractive: Sampling System Chiller System Sampling probe Heated sample line Filters Cooler Pump Flow meters Pressure regulators 49

50 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 50

51 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 51

52 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 52

53 Extractive: Data Logger and Software Chiller System The Station manager software offers a full interface of the station: o Complies with 40 CFR Part 60 and 40 CFR Part 75 o Data display & processing o Manual Calibration o Automatic zero/span checks o Power failures log 53

54 Extractive: Data Logger and Software Chiller System (Contd.) The System manager software offers a full interface between different stations: o Manual/Automatic data polling o Data display & processing 54

55 Extractive: Data Logger and Software Chiller System 55

56 Extractive: Calibration System Chiller System NIST traceable Standard Gases Supplied complete with dual stage pressure regulators for accurate controlling of gas output 56

57 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 57

58 Ambient Air Quality Monitoring Stations 58

59 Ambient Air Quality Monitoring Station 59

60 Ambient Air Quality Monitoring Station 60

61 THANK YOU 61