PETRONAS TECHNICAL STANDARDS DESIGN AND ENGINEERING PRACTICE
Guidelines on Selection and Installation of Continuous Emission Monitoring System (CEMS)
PTS 32.31.50.39 MARCH 2009
© 2010 PETROLIAM NASIONAL BERHAD (PETRONAS) All rights reserved. No part of this document may be reproduced, stored in a retrieval system or transmitted in any form or by any means (electronic, mechanical, photocopying, recording or otherwise) without the permission of the copyright owner
PTS Circular 2008- 1 PTS No: Publication Title: Base PTS Version:
32.31.50.39 Guidelines on Selection and Installation of CEMS New PTS
This new PTS 32.31.50.39 - Guidelines on Selection and Installation of Continuous Emission Monitoring System (CEMS) has been developed to streamline the design and implementation CEMS throughout PETRONAS group companies.
This PTS also includes PETRONAS Lessons Learnt and PETRONAS Best Practice for the subject matter Guidelines on Selection and Installation of CEMS
Document Approval
Revision History Date Version
Description of Updates
Author
PREFACE PETRONAS Technical Standards (PTS) publications reflect the views, at the time of publication,of PETRONAS OPUs/Divisions. They are based on the experience acquired during the involvement with the design, construction, operation and maintenance of processing units and facilities. Where appropriate they are based on, or reference is made to, national and international standards and codes of practice. The objective is to set the recommended standard for good technical practice to be applied by PETRONAS' OPUs in oil and gas production facilities, refineries, gas processing plants, chemical plants, marketing facilities or any other such facility, and thereby to achieve maximum technical and economic benefit from standardization. The information set forth in these publications is provided to users for their consideration and decision to implement. This is of particular importance where PTS may not cover every requirement or diversity of condition at each locality. The system of PTS is expected to be sufficiently flexible to allow individual operating units to adapt the information set forth in PTS to their own environment and requirements. When Contractors or Manufacturers/Suppliers use PTS they shall be solely responsible for the quality of work and the attainment of the required design and engineering standards. In particular, for those requirements not specifically covered, it is expected of them to follow those design and engineering practices which will achieve the same level of integrity as reflected in the PTS. If in doubt, the Contractor or Manufacturer/Supplier shall, without detracting from his own responsibility, consult the owner. The right to use PTS rests with three categories of users: 1) 2) 3)
PETRONAS and its affiliates. Other parties who are authorized to use PTS subject to appropriate contractual arrangements. Contractors/subcontractors and Manufacturers/Suppliers under a contract with users referred to under 1) and 2) which requires that tenders for projects, materials supplied or - generally - work performed on behalf of the said users comply with the relevant standards.
Subject to any particular terms and conditions as may be set forth in specific agreements with users, PETRONAS disclaims any liability of whatsoever nature for any damage (including injury or death) suffered by any company or person whomsoever as a result of or in connection with the use, application or implementation of any PTS, combination of PTS or any part thereof. The benefit of this disclaimer shall inure in all respects to PETRONAS and/or any company affiliated to PETRONAS that may issue PTS or require the use of PTS. Without prejudice to any specific terms in respect of confidentiality under relevant contractual arrangements, PTS shall not, without the prior written consent of PETRONAS, be disclosed by users to any company or person whomsoever and the PTS shall be used exclusively for the purpose they have been provided to the user. They shall be returned after use, including any copies which shall only be made by users with the express prior written consent of PETRONAS. The copyright of PTS vests in PETRONAS. Users shall arrange for PTS to be held in safe custody and PETRONAS may at any time require information satisfactory to PETRONAS in order to ascertain how users implement this requirement.
TABLE OF CONTENT 1. INTRODUCTION....................................................................................................1 2. REGULATORY REQUIREMENTS ........................................................................3 3. MONITORING TECHNOLOGY (SAMPLING SYSTEM) ........................................4 3.1
Extractive Sampling Systems Method ........................................................4
3.2
In-situ Systems ...........................................................................................8
4. ANALYTICAL TECHNIQUES...............................................................................11 5. CEMS INSTALLATIONS ......................................................................................12 6. ALTERNATIVE METHOD (PREDICTIVE EMISSIONS MONITORING)..............14 7. CEMS-DATA INTERFACE SYSTEMS (CEMS-DIS)............................................15 7.1
Hardware ..................................................................................................16
7.2
DIS Communication Hardware Requirement ...........................................16
8. REFERENCES.....................................................................................................18 APPENDICES Appendix 1 CEMS Monitoring Technology: Dilution Systems....................................19 Appendix 2 Typical Blow-back system for probe .......................................................20 Appendix 3 In-Situ Systems: Close-coupled Laser monitoring system......................21 Appendix 4 In-situ system: Path (cross-duct) systems (double-pass transmissometer) ...................................................................................................................................22 Appendix 5 Analyzers Technique ..............................................................................23 Appendix 6 CEMS-DIS ..............................................................................................26
PTS 32.31.50.39 March 2009 Page 1
1.
INTRODUCTION This PTS was established to specify requirements and give recommendations for the design and construction of Continuous Emissions Monitoring System (CEMS) in accordance to Environmental Quality (Clean Air) Regulations 2008 - Draft. This guide also describes the various methods used to continuously monitor pollutants emitted from stationary sources.
1.1
Definitions DOE
Department of Environment
PEFS
Process Engineering Flow Scheme.
Piping class
An assembly of piping components, suitable for a defined service and design limits, in a piping system. Piping classes for refining and chemicals are contained in PTS 31.38.01.12; piping classes for exploration and production are contained in PTS 31.38.01.15.
Nafion®
Nafion® is a DuPont™ copolymer of tetrafluoroethylene (Teflon®) and perfluoro-3, 6-dioxa-4-methyl-7-octene-sulfonic acid. Highly resistant to chemical attack, and it also exhibits highly selective absorption and transfer of compounds.
CEMS
Continuous Emissions Monitoring System
PEMS
Predictive Emissions Monitoring System
CEMS-DIS
CEMS Data Interface System
DCS
Distributed Control System
AMADAS
Analyzer Management and Data Acquisition System
CSV
Comma Separated Value. A file format is a particular way to encode information for storage in a computer file. Particularly, files encoded using the CSV format is used to store tabular data.
TDLAS
Tunable Diode Laser Absorption Spectroscopy. A new technology using tunable laser as optical source.
NIR
Near Infra-red is a spectroscopic method which uses the near infrared region of the electromagnetic spectrum (from about 800 nm to 2500 nm)
NDIR
Non-Dispersive Infra red uses a wider infra red region of the electromagnetic spectrum.
TPM
Total Particulate Meter
VOC
Volatile Organic Carbon
FID
Flame Ionization Detector
UV-VIS
Ultraviolet Visible
Process line
The piping used for transport of fluids (other than sample lines).
Sample
A representative portion of the product or process stream having all relevant properties of the product or the process stream itself.
Sample conditioning system
One or more devices that properly prepare a portion of the sample from the sample transport system for testing by the process analyzer to meet the requirements of the analyzer.
Sample line
The tube or pipe used for transporting the sample.
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Sample preconditioning system
Consists of one or more devices that condition the sample (pressure, temperature, flow, change of state) so that it is suitable to be transported to the sample conditioning system. The sample pre-conditioning system forms part of the sample take-off system.
Sample probe
A device (usually in the form of a special tube) that is inserted into a defined point in the bulk of the process stream to extract a small portion as a sample.
Sample recovery system
A system that collects waste sample and/or by-products from the analyzer system for the purpose to either return them to an assigned point of disposal or to a suitable point in the process.
Sample take-off connection
A piping connection for the extraction of the sample from the process line and through which a sample probe may be inserted into the process.
Sample take-off point
The exact location from where the sample is extracted in the process, i.e., the location of either the tip of the sample probe or the pipe wall connection from where the sample fluid leaves the process piping.
Sample take-off system
The system that includes the sample probe and downstream components up to the connection with the sample transport system.
Sample transport system
A system used to transport a sample from the sample takeoff,
Sampling system
The complete system that includes the sample take-off, sample transport and sample conditioning systems.
either to the sample conditioning system (and from there to the analyzer) or directly to the analyzer, and to return the waste sample, if any is collected, from the sample conditioning system, either to a suitable point in the process or to a suitable utility system.
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2.
REGULATORY REQUIREMENTS Refer to Environment Quality (Clean Air) Regulation 2008 - Draft. Table 1 is the summarized limits based on DOE regulation. This table is subject to change by DOE. Table 1 – DOE Regulatory Pollutants Limits Source Activities Heat & Power Generation
Source Capacity
Non-ferrous 1 metals Production & Processing
Oil & Gas industries: Refineries (all sizes) Non metallic industry
Palm Oil Mills (all sizes)
SO2 NO2 CO Total PM SO2 NO2 CO Total PM NO2 CO NO2 CO
≥ 10 MW
Solid & Liquid Fuels
Boiler
≥ 10 MW
Gaseous fuels
Source Capacity Sinter plants (waste gas from the sintering belt) Blast furnace (@ 3% O2 ) Basic Oxygen furnace Electric Arc Furnaces Sinter plants (waste gas from the sintering belt) Production of copper & zinc Production of lead or cadmium Primary Aluminum Secondary Aluminum Catalytic Cracking Calcination Cement kilns (all sizes) Glass furnaces ( ≥ 1 t/day) Ceramic furnaces (>10 t/day)
Waste incinerators (all sizes)
Pollutants
Boiler
Combustion turbines ≥ 10 MW Combustion turbines ≥ 10 MW Source Activities Iron & Steel Mills (all sizes) Production & Processing
Fuel Type
Gaseous fuels Liquid Fuels
Fuel Type
Limit Value (mg/m3) 500 500 200 50 35 350 50 5 150 100 200 100
Data Frequency ½ H Average ½ H Average ½ H Average ½ H Average ½ H Average ½ H Average ½ H Average ½ H Average ½ H Average ½ H Average ½ H Average ½ H Average
SO2 NO2 Total PM Total PM
Limit Value (mg/m3) 500 400 50 50
Data Frequency ½ H Average ½ H Average ½ H Average ½ H Average
Total PM Total PM SO2 NO2 Total PM Total PM
50 20 500 400 50 20
½ H Average ½ H Average ½ H Average ½ H Average ½ H Average ½ H Average
Total PM
10
½ H Average
Total PM Total PM Total PM SO2 Total PM
10 10 40 1200 40
½ H Average ½ H Average ½ H Average ½ H Average ½ H Average
NO2 Total PM SO2 NO2 Total PM SO2 NO2 Total PM Total PM NMVOC as Total C HCl HF SO2 NO2 CO Total PM Opacity (Smoke)
800 50 800 800 50 800 800 50 10 10
½ H Average ½ H Average ½ H Average ½ H Average ½ H Average ½ H Average ½ H Average ½ H Average ½ H Average ½ H Average
10 1 50 200 50 50 20%
½ H Average ½ H Average ½ H Average ½ H Average ½ H Average ½ H Average Minute average
Pollutants
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3.
MONITORING TECHNOLOGY (SAMPLING SYSTEM) Two main principles in monitoring pollutant emissions from stationary sources: 1) Extracting or locating a representative sample (Extractive) 2) Analyzing that sample directly (In-situ) The choice and design of CEMS depends on both the regulatory requirements and the types of pollutants and/or parameters that are to be monitored. The choice of sampling systems has to be compatible with the analyzers used to measure the analytes.
Types of continuous monitoring methods
Extractive
In-situ
Source level
Dilution
Dry
In-Stack
Single pass
Closed couple
Wet
Out-of-stack
Double pass
In-Stack Analyzer
Path
Point
Figure 1 Flow chart of Methods
3.1
Extractive Sampling Systems Method Extractive sampling systems is a system that extracts or withdraw sample from the stack and treat or condition samples to be analyzed. Extractive sampling systems shall be designed and operated in a manner that provides consistently representative samples to the analyzer. The design of the sampling system must eliminate, or at least minimize, any reactions or loss of the medium of interest before they reach the analyzer. There are two types of extractive methods: 1) Source level (Hot-Wet systems and Cold-Dry systems) 2) Dilution (in-stack and out-of-stack)
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3.1.1
Source level: - Hot-Wet (Hot and Wet) systems This type of sampling system design is not preferred as it usually requires high maintenance and limited flexibility to analyze multi component using one analyzer Hot-Wet systems are systems that maintain the sample temperature above its dew point throughout the sampling system and within the analyzer. With this system, the sample being measured is at hot and wet condition (i.e. there is no water removal /condenser unit prior to transporting the sample)
Figure 2 Typical Hot-Wet Systems This system should be considered only for water soluble samples such as HCl, NH3 and VOCs. The hot/wet systems design should take the following factors into consideration: 1) 2) 3) 4)
Water solubility of the samples, Adsorption capability of the samples or compounds, Participations in chemical reactions with other stack gas. Selected analyzer shall be able to withstand hot and wet sample and its measuring technology is insensitive to moisture content.
To minimize the effects of analytes adsorption into sample lines, the sampling lines material selection and operating temperature and pressure shall be considered. High flow rates and short sampling will reduce the effects of analytes adsorption by minimizing the residence time of the samples inside the line. All other accessories shall be selected meticulously to avoid adsorption or condensation. All cold spots within sampling lines such as connectors between heated lines segments shall be eliminated by heating the sample above the minimum dew point of the mixture. The effects of temperature changes between the stack and the analyzer shall be considered to reduce the impact of chemical reactions of gases due to temperature change.
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3.1.2
Source level: - Cold-Dry (Cold and Dry) systems In this design, representative sample of flue gas is withdrawn from the stack, dried by removing water from the sample and cooled to ambient temperature prior transporting sample for analysis by analysers. There are two options in drying the sample: i)
Water removal right after the take-off probe (before sample transport line): •
Drying by means of Nafion® dryer principle, for example, using dry instrument air and Nafion® permeable tubes. The objective of this application is to bring down the sample dew point to the level that heated sample transport line is not required since long heat traced sample line is costly and is known subject to failure and may result in subsequent problems.
•
The dryer has to be correctly sized to sufficiently remove the water to achieve the desired dew point. The design has to include certain protection feature whereby the wet sample will not be transported due to malfunction of the Nafion® dryer system. This is to avoid subsequent problem such as condensation and possibly blockage in the sample line due to sample crystallization. This could result in potential failure to analyzer measuring cell due to wet sample. Refer to Figure 3 below for a typical extractive (cold-dry) system using this method.
•
The moisture remover is recommended to be mounted not exceeding 5m from to the stack or duct and shall be thermal insulated.
•
Sample line shall be installed to carry the clean, dry and cool gas to the analyzer which can be located at ground level (refer figure 3). Note that, when applying this option, permanent maintenance access has to be provided to maintain the Nafion® dryer unit & its accessories at the stack.
Nafion® dryer
Pump
Heated
Analyzer Stack
Instrument Safe vent Figure 3 Typical extractive (Cold-dry): Moisture removal before sample transport line
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ii)
Water removal at ground level (after sample transport line): •
Water or moisture removal will be done after the heated sample transport line at the sample conditioning system by means of chiller or other means to condense the water in the sample and later knock out the condensed water (refer figure 4). Note that by using this method, water soluble analytes such as HCl, NH3, VOC, H2S, SO2 may be lost as part of water being knocked out from the condenser.
•
This method has disadvantages of high maintenance on heat trace sample line (due the design of the heat trace) and potential sampling clogging. Hence, it is not recommended to use this method if other option can be applied.
Safe vent
Probe Heat trace
Stack Sample drying via Nafion® dryer and/or
Analyzer
cooler Sample Pump Figure 4 Typical extractive (Cold-dry): Moisture removal after sample transport line
3.1.3
Dilution Systems This technique of extractive systems quantitatively dilute stack gas samples with clean dry air to reduce the sample dew point to eliminate need for heated sample transport lines or moisture removal unit prior to sample analysis by analysers. To reduce the sample dew point to an acceptable value will typically require dilution ratio within 50:1 to 100:1 depending on the moisture content and other components in the stack. Thus, when applying this method, the concentration of analytes left after being diluted shall still be able to be detected or measured by the analyzer (refer Figure 5 below). There are two types of dilution system available; 1) In-stack 2) Out-of-stack. In-stack dilutions probes shall use critical orifice to ensure the sample extraction flow rate is independence of the aspirator flow to give more constant sample flow rate and consistent dilution (refer figure 1 in the Appendix 1).
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Biases in monitoring results may occur where in-stack dilution probe is subjected to varying stack temperature, pressure, or molecular weight. These parameters may affect the sonic flow across the critical orifice thus the pressure drop across it. For the case of varying stack temperature, Out-of-stack dilution shall be used to eliminate or minimize the stack variations by putting the temperature control dilution box outside the stack and leaving only sample probe inside the stack (refer figure 2 in the Appendix 1).
Calibration gas
Dilution Diluted
Analyzer Stack
Dilution air
Zero air generator
Instrument air
Figure 5 Typical dilution system drawing
3.2
In-situ Systems In-situ systems measure the concentration of pollutants gas directly by placing the sensor within the stack or by projecting a light beam through a portion of the stack gas stream and analyzing various spectral phenomena. The probes shall be kept clean by using blowback function (refer to Appendix 2 for the typical drawing) There are various types of in-situ systems; namely point (close-coupled), path (cross-duct) or path (in-situ probe). They are further elaborated below:
3.2.1
Point (Close-coupled) systems. Close-coupled system is a method whereby the measuring sensor is placed as close as possible to the stack. However, the analyzers have to be able to tolerate stack heat and harsh environment (refer Figure 6). Typically the instruments consist of an electrochemical or electro-optical sensor. This method can be used when extractive cold-dry method cannot be applied due to high solubility of components of interest in water. Selection of suitable analyzer and accessibility issue shall be considered in selecting this type of system.
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Figure 6 Close-coupled Systems
3.2.1.1 In-stack (in-situ) CEMS sensor This method is a newer technology using specific wavelength light absorbance method. It can be used to measure multi components with single analyzer. Refer to Figure 7 below for typical In-situ CEMS sensor.
Figure 7 Sample of in-stack Analyzers Careful consideration by consulting the manufacturer shall be done when using this type of method because presence of background gas possibly will affect the analysis of the desired components. It is imperative that all gas component presence (including those that are not required to be measured) to be make known to the manufacturer to verify its suitability.
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3.2.2
Path (cross-duct) systems This method is basically an energy source projected across the stack from one side to the other with specified target gases absorb this energy at specific wavelength (refer to Appendix 4). For tough applications, Laser based or UV/IR In-situ systems shall be used. For example, NH3 measurement is required as part of the CEMS and due to NH3 being a sticky compound, (that tend to stick to extractive sampling system), cross stack in-situ system is preferred. Careful consideration by consulting the manufacturer shall be done when using this type of method because not all components can be measured using in-situ systems. An across-the-stack unit also applied for opacity/dust measurements.
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4.
ANALYTICAL TECHNIQUES PTS 32.31.50.12 (On-line Process Stream Analysis-Analysers) shall be referred for the selection of analyzers. Appendix 5 of this PTS can be referred for the various measuring principles of CEMS analysers. Methods used to measure air pollutants are summarized as per table 2. Selection of analyzers shall depend on type of gas monitored and DOE requirements. Table 2 can be used as a guide in selecting analyzers for CEMS system. Table 2: List of Pollutants and Measurement Techniques Pollutant
NDIR, TDLAS NDIR, TDLAS TDLAS, NIR, OPTICAL
Extractive or In-situ Extractive or In-situ Extractive or In-situ In-situ (path)
Typical Expected Concentration Range 2-12% 0-100ppmV 0-50ppmV 0-10%, PM10
Extractive, In-situ Extractive, In-situ
0-4000ppmV 0-1000ppmV
HC (up C ) VOC Mercury HF
NDIR, Chemiluminescence NDIR, UV-VIS, UVFluorescence FID FID UV-VIS TDLAS, NIR
0-50ppmV 0-50ppmV
NH3
TDLAS
H2S
UV-VIS, TDLAS, Lead acetate tape
Extractive Extractive Extractive Extractive, In-situ (path), Extractive, in- situ (path) Extractive, In-situ
CO2 CO HCl OPACITY / TPM NOx SO2
Note 1:
Measurement Technique
Typical Sampling system type
0-50ppmV 0-50ppmV 0-50ppmV
Analyzer sensitivity and resolution shall be able to detect the diluted sample normally 10-100 times lower than stack composition.
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5.
CEMS INSTALLATIONS Each analyzers and equipment installed as CEMS system should be in compliance with one or more of the international standards such as US-EPA, TUV and MCERTS. It is not necessary to meet all standards. The sampling location should be accessible for system maintenance and repairs and for stack installations of in-situ analyzers factors such as vibration, lightning, ambient atmosphere and temperature extremes must be considered (refer Figure 8 below). The desired the probe location would be (note 1): 1) Eight (8) equivalent internal stack/duct diameter downstream and two (2) equivalent internal stack/duct diameter (D) upstream of any flow disturbances. 2) An opacity monitor requires four (4) equivalent internal stack/duct diameters downstream and two (2) equivalent internal stack/duct diameters (D) upstream of any flow disturbances. The sample probe measurement point must be no closer than 30% of the stack wall or 45% farther than the stack diameter (refer Figure 9 below). Note 1:
Reference to DOE’s “Volume 1: Guideline for Installation and Maintenance of Continuous Monitoring Systems (CEMS) for Industrial Premises/Facilities”
2D Probe placement within this area
8D
In
Figure 8 Probe placement
PTS 32.31.50.39 March 2009 Page 13
< 30% from stack
< 45% of internal diameter
Figure 9 Probe point location
Flue gas emission contains a lot of particulates especially for incinerator stack emission. Therefore, it is necessary to have auto-cleaning features of the stack probe’s filter otherwise the probe’s filter will get clog easily. A typical self cleaning feature by means of auto blowback using instrument air is shown in Appendix 2. The solenoid valve’s open/close timer is preferably controlled by the plant DCS system or alternatively can be controlled using dedicated timer installed locally.
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6.
ALTERNATIVE METHOD (PREDICTIVE EMISSIONS MONITORING) Applying CEMS is costly and subject to maintenance and reliability issues. PEMS is another alternative method to hardware CEMS for monitoring emissions based on emission model to predict emission and uses process operation data and ambient condition to calculate (predict) the pollutant emitted. This method has been accepted internationally and has been used in many countries such as UK, Canada, Japan, Australia, USA etc. This is the cheapest and reliable method available thus far. Figure 10 below shows simplified PEMS model
Figure 10. PEMS modeling
PEMS can only predict certain pollutants. The most prevalent pollutants predicted are nitrogen oxides (NOx), followed by carbon monoxide (CO). Regulations generally require that emissions be normalized to a common oxygen (O2) or carbon dioxide (CO2) basis. Pollutants such as sulfur dioxide (SO2) or specific organic compounds are related to the sulfur content in fuels or the level of the organics in a material. The prediction of these pollutants is done by mass-balance calculations and to consult local authority on its application and approval for PEMS. It is imperative that DOE being consulted prior to applying this method because it is not yet being specified as an optional method under the Clean Air Act 2008 - Draft.
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7.
CEMS-DATA INTERFACE SYSTEMS (CEMS-DIS) CEMS-DIS (data interface system) is an on-line reporting and monitoring system for emission monitoring for DOE. With this system DOE will be able to monitor plant or facilities emission in real time. Typical layout of the system can be referred to figure 11.
Figure 11. Typical lay-out of CEMS-DIS
Plant database (i.e. DAS/AMADAS/Data logger)
WWW
DCS Via internet OR Via Plant Database System
Via dial up modem DOE Server DOE OFFICE
PLANT Legend:
DB
- Firewall - Alternate route - Modem/router
CEMS-DIS
DeMilitarized Zone (DMZ)
Emission data recorded and/or analyzed at industrial premises shall be at the interval of thirty (30) minutes for gases, one (1) minutes for opacity (smoke) or as required by DOE (note 2). Industrial operators or end-user must inform DOE of any incidence that may lead to incorrect or missing data, in accordance to and in conformance to data error coding as specified in DEO CEMS-DIS handbook (refer table 1 in the Appendix 6). Industrial premises must be pre-registered with DOE and listed in DOE CEMS registry database. The DIS system for the end-user can be divided into 2 main components: 1. Industrial premises’ CEMS equipments sensors, probes, data loggers, and data acquisition system (DAS) or AMADAS (Analyzer Management and Data Acquisition Systems). a. For User with CEMS but without Plant database system (i.e. DAS/AMADAS System) i.
ii.
If data is in analogue format, industrial premises shall have a proper analoguedigital converter. For industries that don’t have DAS, a data logger would be the alternative. Another alternative is to have the DCS vendor to create a program so it can send the data in a format that can be received by DIS (for example, ASCII’s CSV format)
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2. An intermediary component called CEMS Data Interfacing System (CEMS-DIS) to store data from DAS and communicate with State DOE server for CEMS data transferring purposes.
Note 2:
7.1
Reference to DOE’s “Volume 2: Guideline for CONTINUOUS EMISSION MONITORING SYSTEMS –– DATA INTERFACE SYSTEM (CEMS-DIS) for Industrial Premises/Facilities”
Hardware The hardware requirements for DIS are: 1. A server or PC (that act as a server and preferable industrial type PC). 2. Internet communication hardware to link to State DOE’s server
7.2
DIS Communication Hardware Requirement DOE State server must be given access to DIS PC at any time. There are 2 methods the DOE State server can access DIS:1. Via internet connection 2. Via modem to modem connection.
7.2.1
DIS Communication via Internet Connection 7.2.1.1
For industrial premises with ready internet connection 1. Industry premise/facility with 24 hours daily internet connection could use their existing internet connection. 2. Assign a fixed IP for DIS usage and register this IP address with DOE.
7.2.1.2
For industrial premises without ready internet connection Industry premise/facility without internet connection should use lease line or broadband. Take note of the stability of the internet provider service connection when opting for this type of communication and also the data security aspect of it (i.e. sufficient firewall).
7.2.2
DIS Communication via Modem to Modem connection Dial up via fixed telephone line: Hardware requirements; 1. 56k Modem or equivalent 2. A single dedicated fixed telephone line The modem is to be installed on DIS PC and the external modem shall be used with power surge, power spikes, and lightning arrestor. A single dedicated fixed phone line shall be allocated for DIS use.
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7.2.3
CEMS-DIS Data Format and Data Structure The industrial premises shall follow the following DOE requirements: a) All stacks monitoring data in CEMS-DIS shall be stored in MySQL database format with the following specifications: I. II. III. IV. V. VI.
Database software: MySQL version 4.0.23 or later (must support MySQL version 4.0.23 component library) Database name: dis_reading No. of table: 1 Name of table: reading No. of fields: 15 Field definitions: (Appendix: Table 4.1)
b) It is recommended by DOE that industrial premises keep the monitoring data in the CEMS-DIS database for at least five (5) year as part of data archiving (note 3). c) DIS shall store averaged data for some specified interval depending on parameter as specified by the DOE requirement. d) DIS data handling and coding shall be as specified by the DOE. Note 3:
Reference to DOE’s “Volume 2: Guideline for CONTINUOUS EMISSION MONITORING SYSTEMS - DATA INTERFACE SYSTEM (CEMS-DIS) for Industrial Premises/Facilities”
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8.
REFERENCES In this PTS reference is made to the following publications: NOTES: Unless specifically designated by date, the latest issue of each publication shall be used (together with any amendments/supplements/revisions thereof). USEPA Handbook 1997 On-line Process Stream Analysis-Sample take-off and Transportation On-line Process Stream Analysis-Sample Conditioning On-line Process Stream Analysis-Analysers Piping classes – refining and chemicals Piping classes – exploration and production Environment Quality (Clean Air) Regulation 2008 - Draft GUIDELINE FOR THE CONTINUOUS EMISSION MONITORING SYSTEMS - DATA INTERFACE SYSTEM (CEMS-DIS) -
Vol. 2 and 3 PTS 32.31.50.10 PTS 32.31.50.11 PTS 32.31.50.12 PTS 31.38.01.12 PTS 31.38.01.15 Vol. 1 and 2
PTS 32.31.50.39 March 2009 Appendix 1
Appendix 1 CEMS Monitoring Technology: Dilution Systems This type of extractive systems quantitatively dilute stack gas samples with clean dry air to reduce the relative moisture content so that the sample will remain above the dew point with little or no heating. With possible moisture condensation is eliminated, the need of complicated and expensive heated lines can be replaced with much more simpler and economical solutions. Dilutions ratios ranging from 20/1 to 1000/1 are used in practice.
Figure 1 In-stack dilution probe
Figure 2 Out-of-stack systems
PTS 32.31.50.39 March 2009 Appendix 2
Appendix 2 Typical Blow-back system for probe
PTS 32.31.50.39 March 2009 Appendix 3
Appendix 3 In-Situ Systems: Close-coupled Laser monitoring system
PTS 32.31.50.39 March 2009 Appendix 5
Appendix 4 In-situ system: Path (cross-duct) systems (double-pass transmissometer)
PTS 32.31.50.39 March 2009 Appendix 5
Appendix 5 Analyzers Technique 5.1
Tunable Diode Laser Absorption Spectroscopy (TDLAS) A basic TDLAS analyzer consists of tunable diode laser light source, optical transmitter, optical receiver and detectors. The emission wavelength of the diode laser is tuned over the characteristic absorption lines of the gas of interest in the path of laser beam. The tunable diode laser provides excellent monochromaticity with narrow breadth of spectrum line which is less then 0.0001nm against 20-30nm for traditional IR light source. Applicable wavelength is within 700-2500nm which fall within the IR range. Intensity of laser signal will be reduced with present of gas of interest and the signal reduction can be detected by a photodiode and then used to determine the gas concentration. The transmitted intensity can be related to the concentration of gas of interest by the Beer-Lambert Law. The advantage of TDLAS is its ability to achieve very low detection limits. Typical application of TDLAS is to measure O2, CO, CO2, H2O, H2S, HF, HCl, HCN NH3, CH4, C2H2, C2H4, etc.
5.2
Non Dispersive Infrared (NDIR) Method NDIR analyzer contains an optical system consisting of an infrared (IR) source, sample cell, and detectors. In front of the thermopile detectors are interference-type filters. These filters are designated the reference and measuring filters. The sample flows continuously through the sample cell, absorbing energy at various wavelengths throughout the IR spectrum. The wavelengths and intensities of absorption peaks throughout the spectrum are characteristic of the specific compounds that are present in the sample. In any photometric analysis, there is always the analysis of the component of interest, and other components (background) which are not of measuring interest. Both the “component of interest” and the background component may have complex IR absorption spectra. The quantitative measurement of a compound using NDIR is based on the Beer-Lambert Law, where the intensity of a beam of monochromatic radiation transmitted through a sample decreases exponentially as the concentration of the absorbing sample increases. The use of filters and detectors allows cancellation of energy changes due to turbidity, dirty sample cell windows, aging of the source and sudden temperature changes. The center pass band of the measuring filter is selected to transmit energy in a narrow region (band pass) where the component of interest absorbs strongly by comparison with the background components. The center pass band of the reference filter is generally selected to transmit energy in a band pass region where the background absorption of IR energy is equivalent to that seen by the measuring filter, and also to be in a region where the component of interest has minimal absorption of energy. The IR radiation passes through the sample and filters and strikes the detectors, which convert the radiation into electrical signals, and are then amplified. Signal processing involves comparing the measuring and reference signals in order to give a readout representing the “component of interest” concentration in the sample.
5.3
Near Infrared Method Generally NIR analyzer consists of source module, sample cell, filter wheel and detector module. The energy source for the analyzer is most commonly provided by as a high intensity quartz iodine lamp located in the source module. Quartz iodine was chosen because it produces sufficient NIR to operate the system and maintains a nearly constant brightness over its lifetime.
PTS 32.31.50.39 March 2009 Appendix 5
The sample cell, generally constructed of 316SS, is located in the path of the NIR radiation, between the source and the detector modules. Each compound in the sample path exhibits its own characteristic absorption spectrum. Due to the possible variation of absorption with temperature, it is necessary to maintain the sample at a constant temperature during analysis. After energy has passed through the sample, it arrives at the filter wheel where it is fed alternately through two filters (measuring and reference) before reaching the detector. These filters are specially selected for each application according to the absorption characteristics of the compounds under analysis. At the detector, infrared energy is transformed into electrical pulses. Typical application is to measure moisture in various background gases, HCl and HF.
5.4
Chemiluminescence Method Chemiluminescence method is basically applied for Nitrogen Oxides measurement. The light emitted from the chemiluminescent gas phase reaction of nitric oxide [NO] and ozone [O3] as follows: NO + O3 Æ NO2* +O2 NO2* Æ NO2 + hv The reaction of NO with ozone results in electronically excited NO2 molecules as shown in the first equation above. The excited NO2 molecules release their excess energy by emitting a photon and dropping to a lower energy level as shown in the second equation. The light intensity produced is directly proportional to the [NO] concentration present. In measuring NO mode, the sample gas is routed directly into the reaction cell. Any NO gas present reacts with ozone, producing light as described above. In measuring NOx mode, the sample gas is routed through a NO2 to NO converter, and any NO2 present is reduced to NO. The NO initially present remains as NO, therefore the signal is the sum of NO and NO2 present in the sample gas stream.
5.5
UV Absorption UV-VIS based analyzer utilizes the UV region of the electromagnetic spectrum from 200nm to 800nm. It consists of UV light source, sample cell, chopper wheel with filters and a detector. Similar to the basic principles of most photometer, measurement using UV-VIS is based BeerLambert Law. When a UV beam of light passes through a sample cell with a gas of interest in it, the intensity of emergent light will always be less than then incident light. The fraction of incident light that is absorbed is a function of the cell path and concentration of the species in it. Typical application includes measurement of SO2, H2S, Cl2, ClO2, OCl, F2 and Phosgene.
5.6
UV Fluorescence UV-Fluorescence-based analyzer is typically used for Sulfur Dioxide measurement. SO2 absorbs in the 190 nm - 230 nm region free of quenching by air and relatively free of other interferences. Interferences caused by PNA (poly-nuclear aromatics) can be reduced by a filter which removes PNA selectively through a membrane without affecting SO2 sample gas. The UV lamp emits ultraviolet radiation which passes through a 214 nm band-pass filter, excites the SO2 molecules, producing fluorescence which is measured by a PMT with a second UV band-pass filter. Ultraviolet light is focused through a narrow 214 nm band-pass filter into the reaction chamber. Here it excites the SO2 molecules, which give off their characteristic decay radiation. A second filter allows only the decay radiation to fall on the PMT. The PMT transfers the light energy into the electrical signal which is directly proportional to the light energy in the sample stream being analyzed.
PTS 32.31.50.39 March 2009 Appendix 5
5.7
Flame Ionizations Detector Flame ionization detector is the most popular detector for the analysis of hydrocarbon due to high sensitivity, wide linear dynamic range, low dead volume, and responsive to trace levels of almost all organic compounds. This detector adds hydrogen to the column effluent and passes through a jet, in which it is mixed with entrained air and burned. The ionized gas (charged particles and electrons produced during combustion) passes through a cylindrical electrode. A voltage applied across the jet and the cylindrical electrode sets up a current in the ionized particles. An electrometer monitors the current to drive and measure the component concentration.
Figure 5-1 Flame ionization sensor
5.8
Optical Measurement Technique Optical method is applied for opacity or dust monitoring. The instrument is based on the principle of transmissometry. A light beam with specific spectral characteristics is projected through the effluent stream of a stack or duct exhausting combustion or process gases. The amount of light reflected back to the instrument from reflector after passage through the stream is compared with the maximum possible return when no effluent is present. The return signal is an indication of the transmittance of the effluent. Particulate matter in the effluent stream attenuates the projected light beam. The opacity of the gas stream is determined by measuring the attenuated signal from the instrument. The opacity is usually expressed as a percentage. Opacity measurement can be correlated with particulate mass. Simultaneous collection of attenuation data and gravimetric analysis of the particulate mass of the stack effluent can be performed over a wide range of particulate mass condition in order to generate a correlation curve.
PTS 32.31.50.39 March 2009 Appendix 6
Appendix 6 CEMS-DIS Table 1. Definitions of 15 Fields in reading table Data Type Field Description Double (9,0) • primary key • value must unique and NULL value is NOT allowed Varchar • to be assigned by DOE Varchar • to be assigned by DOE Date & Time • date & time of stack monitoring data (YYYY-MM-DD • 24 hour time format HH:MM:SS) Double (5,2) • Sulphur dioxide (SO2) • Unit MUST in mg/Nm3
No 1
Field Name reading_id
2 3 4
factory_id stack_id read_datetime
5
SO2
6
NO2
Double (5,2)
•
Nitrogen oxides, expressed as nitrogen dioxide (NO2) Unit MUST in mg/Nm3
7
CO
Double (5,2)
• •
Carbon Monoxide (CO) Unit MUST in mg/Nm3
8
CO2
Double (5,2)
• •
Carbon Dioxide (CO2) Unit MUST in mg/Nm3
9
HCl
Double (5,2)
• •
Hydrogen Chloride (HCl) Unit MUST in mg/Nm3
10
HF
Double (5,2)
• •
Hydrogen Fluoride (HF) Unit MUST in mg/Nm3
11
H2O
Double (5,2)
• •
Water Vapour (H2O) Unit MUST in mg/Nm3
12
O2
Double (5,2)
• •
Oxygen (O2) Unit MUST in %
13
NMVOC
Double (5,2)
• •
NMVOC as total C Unit MUST in mg/Nm3
14
Total PM
Double (5,2)
• •
Total PM Unit MUST in mg/Nm3
15
Opacity
Double (5,2)
• •
Opacity (Smoke) Unit MUST in %
•
