CODEL DCEM2000 User manual

TECHNICAL MANUAL
Model DCEM2000
Dust Monitor
(with Ball Valve)
CODEL International Ltd.
Station Building, Station Road, Bakewell, Derbyshire DE45 1GE United Kingdom
t : [phone] f : [phone] e : [email protected] web : www.codel.co.uk
OPS.086 Issue : B Rev. : 1 Date : 11/8/10 Doc. i/d : 0086/6 Ref. : 080047

CODEL
OPS.086 Issue : B Rev. : 1 Date : 11/8/10 Doc. i/d : 0086/6 Ref. : 080047

CODEL
CODEL International Ltd is a UK company based
in the heart of the Peak District National Park at
Bakewell, Derbyshire. The company specialises
in the design and manufacture of high-technology
instrumentation for the monitoring of combustion
processes and atmospheric pollutant emissions.
The constant search for new products and
existing product improvement keeps CODEL one
step ahead. With a simple strategy, to design
well-engineered, rugged, reliable equipment,
capable of continuous operation over long
periods with minimal maintenance, CODEL has
set standards both for itself and for the rest of the
industry.
All development and design work is carried out
‘in-house’ by experienced engineers using proven
state-of-the-art CAD and software development
techniques, while stringent assembly and test
procedures ensure that the highest standards of
product quality, synonymous with the CODEL
name, are maintained.
High priority is placed upon customer support.
CODEL’s dedicated team of field and service
engineers will assist with any application problem
to ensure that the best possible use is derived
from investment in CODEL quality products.
If you require any further information about
CODEL or its products, please contact us using
one of the numbers below or alternatively visit our
web site.
t : [phone]
f : [phone]
CODEL offices, Bakewell, Derbyshire
e : [email protected]
web : www.codel.co.uk
OPS.086 Issue : B Rev. : 1 Date : 11/8/10 Doc. i/d : 0086/6 Ref. : 080047

CODEL
OPS.086 Issue : B Rev. : 1 Date : 11/8/10 Doc. i/d : 0086/6 Ref. : 080047

Technical Manual CODEL
Contents
1. CODEL DCEM2000 Analyser – Introduction 1
1.1. Foreword 1
1.2. DCEM2000 Basic Principles 2
1.3. User Interface 2
1.4. Analogue and Logic Outputs 2
1.5. CDC Serial Port - for use with the CODEL IEM system 2
2. Overview of the CODEL Model DCEM2000 Dust Monitor 3
2.1. Introduction 3
2.2. Transceiver Units 3
2.3. Signal Processor Unit (SPU) 3
2.4. Station Control Unit (SCU) 4
3. Measurement Principle 5
3.1. Window Compensation 6
4. Specification 8
5. Installation 9
5.1. Equipment List 9
5.2. Siting the Equipment 9
5.3. Installation 9
5.3.1. Air Purges 10
5.3.2. Ball Valves 11
5.3.3. Transceivers 11
5.3.4. Signal Processor Unit 12
6. Electrical Connections 13
6.1. Installation and Connection of Cables 13
6.2. Connection Schedule 13
7. Commissioning 16
7.1. Pre-Commissioning Checks 16
7.2. Install SmartCOM Software 16
7.3. Setting Instrument Gains 16
7.3.1. Alignment 16
7.3.2. Detector levels 18
7.3.3. Zero and span calibration 19
7.3.4. Transmissivities 21
7.3.5. Output Data 21
8. Routine Maintenance 23
9. Fault Finding 24
10. Table of Figures 25
OPS.086 Issue : B Rev. : 1 Date : 11/8/10 Doc. i/d : 0086/6 Ref. : 080047

Technical Manual CODEL
OPS.086 Issue : B Rev. : 1 Date : 11/8/10 Doc. i/d : 0086/6 Ref. : 080047

Technical Manual CODEL
Important
The warning signs (and meanings) shown below, are used throughout these instructions and are intended to
ensure your safety while carrying out installation, operation and maintenance procedures. Please read these
instructions fully before proceeding.
Caution, risk of electric shock.
Caution, risk of danger.
Caution, hot surface.
Earth (ground) terminal.
Protective conductor terminal
OPS.086 Issue : B Rev. : 1 Date : 11/8/10 Doc. i/d : 0086/6 Ref. : 080047

Technical Manual CODEL
OPS.086 Issue : B Rev. : 1 Date : 11/8/10 Doc. i/d : 0086/6 Ref. : 080047

Technical Manual Page 1 CODEL
1 CODEL DCEM2000 Analyser – Introduction
Please take a few minutes to read this section before proceeding with installation. It is designed to
provide an overview of the analyser and its capabilities so that the information given later will be more
easily understood.
1.1 Foreword
SmartCEM is the ultimate solution for continuous monitoring of flue gas emissions. It is a fully integrated
monitoring concept from the basic analysers and their calibration verification packages through to digital
communications, data logging and automatic reporting.
At the heart of this concept is the SmartCEM station containing all the analysers and monitors to provide
comprehensive stack emission monitoring. The SmartCEM Station Control Unit (SCU) provides power to and
communicates with the analysers and monitors within that station. Data from up to 32 SmartCEM stations is
transmitted via a serial digital link (CODEL SmartBUS) to the Central Datapoint where it is logged on a
dedicated PC or assembled for onward transmission to a plant computer or DCS.
The arrangement of a typical SmartCEM system is illustrated in Figure 1.
Figure 1 : Typical SmartCEM System Arrangement
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1.2 DCEM2000 Basic Principles
The DCEM2000 is a dual-pass transmissometer configured for the measurement of opacity and dust
concentration within the flue gas. Its unique optical arrangement provides continuous measurements of
transmissivity of visible light across the stack in opposite directions, providing not only an accurate average of
the dust loading in the stack, but a dynamic assessment of any mis-alignment errors that may occur due to
stack movement.
The monitor incorporates integral automatic procedures for determining zero and span and interfaces directly
with the SmartCEM local data bus, so that all diagnostic and measurement data may be accessed by the
Station Control Unit (SCU).
1.3 User Interface
The analyser is supplied with SmartCOM PC software that enables a PC connected to the SCU to display all
real-time measurements as well as the setting-up and display of all the analysers’ configurable operating
parameters. This interface includes a diagnostic mode that allows interrogation of the condition of the analysers’
critical functions for service and trouble-shooting purposes.
1.4 Analogue and Logic Outputs
The SCU is equipped with an analogue output (0/4-20mA) for each of the seven measurement channels. Each
output is freely configurable for any span (within the limits for that measurement) and measurement unit (vpm
or %, mg/m3, mg/Nm3).
Volt-free contact outputs (110V DC/125V AC @ 1A max.) are provided for data valid and measurement alarm
level (common output for all measurement channel alarms).
1.5 CDC Serial Port - for use with the CODEL IEM system
The CDC is equipped with a 2-way serial communications port for use with the CODEL Integrated Emissions
Monitoring (IEM) system. On plant where more than one CODEL analyser is installed, this is the preferred
method and, even for a single analyser installation, can provide significant benefits. The main ones are :
•Up to 32 SCUs can be connected to a CDC via a single data bus.
•No corruption of digital data, even over long distances.
•Common data (e.g., normalisation measurements and plant status) can be transmitted to all
relevant measurement channels and analysers from a single input.
•Real-time display can show all measurements simultaneously.
•Multi-level and period alarms can be freely configured for any measurement data set.
•Up to 5 years data can be logged and instantly recalled in graphical or tabular format.
•All processor user interface functions can be carried out from a central control point, i.e. once
physical installation is complete, all commissioning operations can be carried out from the central
control. Thereafter, real-time analyser operating parameters, including diagnostic data, can be
accessed at any time.
•All real-time and historical data and diagnostics can be accessed remotely via a MODEM.
•Reports can be formatted to suit local legislation and printed automatically.
•Digital data can be transferred directly to the plant DCS or computer.
Full details of the CDC are contained in the IEM software manual.
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2 Overview of the CODEL Model DCEM2000 Dust Monitor
2.1 Introduction
Dust and smoke emissions have for a long time been recognised as major atmosphere pollutants, particularly
since such emissions from stacks are clearly visible to an observer. There has been a requirement for
monitoring, and quantifying these emissions, for some time and a variety of instruments have been marketed
throughout the world for this purpose.
Instruments in the past have, however, generally proved to be unreliable, falling rapidly into disuse or to be so
expensive and complex as to be affordable only by the very large users, such as power stations. The CODEL
DCEM2000 seeks to overcome these problems by providing a reliable, simple to use instrument with low
maintenance requirements.
The instrument is illustrated in Figure 2.
station
control
unit
transceiver transceiver
process gases
signal
processor
unit
Figure 2 : Arrangement of DCEM2000
2.2 Transceiver Units
Two identical transceivers are mounted on opposite sides of the stack. The transceivers each contain a sensing
head comprising a light source, a detector and associated optical assembly; a calibration mirror and rotary valve
and the electronics associated with control and measurement. Should the power fail the ball valves will return to
the closed position to protect the sensing heads.
2.3 Signal Processor Unit (SPU)
The DCEM2000 SPU receives its 48V DC power from the SCU via the 4-core SmartBUS serial data link.
Signals from the two transceivers are processed to derive the transmissivity values and compute the opacity
output. Diagnostic communication is provided via the SCU and a laptop computer operating SmartCOM
software.
Gain adjustments for the transducer detector signals are provided by trim potentiometers in this processor.
Details for adjustment can be found in Section 7. Commissioning.
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2.4 Station Control Unit (SCU)
The SCU provides 48V DC power for the analysers on its local data bus. The 48V DC power input to the SCU is
from a separate power supply fed from 86 to 264V AC maximum.
The SCU is linked to the analyser by means of a 4-wire data bus (local data bus). This bus carries 48V power
to the analyser as well as two serial communication lines referred to as MOSI (Master Out/Slave In) and MISO
(Master In/Slave Out). On this data bus the SCU acts as the Master Device and the analyser as a Slave device.
Note: The SCU may be integral with the Gas Control Unit (GCU) of an accompanying G-CEM4000 gas analyser.
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3 Measurement Principle
Consider the two identical transceivers positioned at either side of the flue (or duct), unit 1 and unit 2.
The transmissivity of light from unit 1 to unit 2 (unit 1 transmitting) can be represented by the equation :
τ12 = K1(Dr2/Dt1) where :
K1 = gain constant to produce τ= 1 (100% transmissivity,
clean air condition)
Dt1 = transmitted light intensity at unit 1
Dr2 = received light intensity at unit 2
The transmissivity of light from unit 2 to unit 1 (unit 2 transmitting) can also be represented by the equation :
τ21 = K2(Dr1/Dt2)
where :
K2= gain constant to produce τ= 1
Dr1 = received light intensity at unit 1
Dt2 = transmitted light intensity at unit 2
This is demonstrated schematically in Figure 3.
Transceiver 2
Transceiver 1
mirror mirror
Detector 2Detector 1
12
21
LED 1 LED 2
Dt1 transmitted light
Dr1 received light
Dt2 transmitted light
Dr2 received light
Figure 3 : Schematic of Principle of Transmissivity
Overall transmissivity of the system (τ) can, therefore, be represented as:
τ= √τ12 . τ21
τ= √K1(Dr2/Dt1) . K2(Dr1/Dt2)
which can be rewritten as :
τ= √K1K2(Dr2/Dt2) . (Dr1/Dt1)
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As the two bracketed terms above are each measured from only one of the transceivers, the output of the
instrument is independent of drift of either detector.
3.1 Window Compensation
A reflector is mounted on the ‘ball’ of a compressed-air operated ball valve enabling it to be rotated in to and out
of the optical path (see Figure 4). Window contamination levels are determined by monitoring the detector levels
Dt at each transceiver with and without the reflector in place. From the data recorded the signal processor
computes the window contamination for each transceiver. The ball valve is actuated by a compressed air supply
that can be switched on and off by a solenoid valve controlled by the SPU.
Figure 4 : Optical Arrangement of the D-CEM2100
When the ball valve is closed the transmitted light signal received by the internal detector is increased by light
reflecting from the mirror on the ball valve, thus:
Dtmirror = Dt + cDt. τl2
where Dt is the transmitted light signal with the ball valve open and ‘c’ is a constant representing the fraction of
the light from the LED that reaches the detector via the ball valve mirror and ‘τl’ is the transmissivity of the
transceiver lens. This term is ‘squarred’ because the light passes through the lens twice en route to the detector.
The value of ‘c’ can be determined by making a measurement of Dtmirror when the lens is known to be clean and
‘τl’ can be set to the value 1, thus:
(Dtmirror) cal = Dt + cDt
c = (Dtmirror) cal – Dt = kcal
Dt
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and therefore, cτl2= Dtmirror – Dt = k
Dt
thus the transmissivity ‘τ’ at the lens can be determined as:
τl2= k
Kcal
and lens contamination is simply 1-τl
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4 Specification
Response Time selectable from 10-seconds
Maximum Path Length 0.5 – 15m
Serial Data Port to communicate with a central processor as part of an
integrated monitoring system.
Dust Calibration By independent analysis (by others)
* see below
Accuracy ±0.2% Opacity
Power input SCU 86-264V AC max.
DCEM 48V DC, 50VA (from SCU)
Air purge consumption 0.25 l/s @ 1.5bar (typical – installation dependent)
Dry (to -20°C)
Clean (better than 10μm)
Air-Operated Ball Valve air pressure required 4bar (60psi) – minimum for correct
Operation
* In the absence of actual data, assume (250/x) mg/m3of dust generates 10% opacity in an x metre wide duct.
This is not a fixed relationship and must be verified by iso-kinetic analysis.
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5 Installation
5.1 Equipment List
The CODEL Model DCEM2000 comprises the following :
•2 x transceivers with 10m of cable (standard length)
•2 x site mounting flanges
•2 x air-operated ball valves
•2 x air purges
•1 x Signal Processor Unit (SPU)
•1 x Station Control Unit (SCU)
5.2 Siting the Equipment
The equipment is designed for mounting on stacks in positions open to the weather. It is fully sealed to IP65
and requires no weather covers.
Consider the following :
•the site must be accessible at both sides of the duct for servicing the sensors.
•the site should be as free as possible from extremes of temperatures and vibration. Permissible
ambient temperature ranges are -20oC to 800C for the sensors and -20oC to 70oC for the SPU.
At low temperatures, condensation might occur on the lens of the instrument causing an
incorrect (high) opacity reading.
•there must be an uninterrupted sight path between each sensor.
•the SPU should be mounted local to the sensors and is supplied with 10m of cable as standard.
5.3 Installation
The analysers and any other items are normally protected for transportation by an expanded foam packing
material. When unpacking, please ensure that smaller items are not discarded with the packing material.
The analysers are supplied with standard 10m cables already connected.
If any items are missing please inform CODEL or your local CODEL supplier immediately.
The installation site should be free of all encumbrances and safety procedures should be observed at all times.
The recommended order, reflected in this manual, is:
•Installation of the stub-pipe and mounting flange
•Installation of air purges and purge air supply
•Fitting of sensor heads, SPU and SCU
•Installation and connection of cables
The sensor heads should be mounted on diametrically opposite sides of the stack.
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Construct the mounting assemblies by welding each site mounting flange to a suitable stub-pipe, nominal bore
75mm. The pipe should be long enough to keep the equipment clear of any duct lagging and it also helps to
insulate the equipment from high duct temperatures. Suggested stub-pipe mounting arrangements are shown
below for a metal stack and for a concrete stack. In the case of a metal stack it may be necessary to fit stiffening
ribs for added rigidity.
Figure 5 : Stub Pipe Arrangement
5.3.1 Air Purges
Before mounting the air purges, ensure that air is supplied to the air purge unit. If this precaution
is not observed then the air purge and the optical surfaces may be severely contaminated.
The purpose of the air purges is to keep the windows of the sensor heads clean. The air purges mount directly
onto the site mounting flanges. Separate the front flange from the air-purge by unscrewing the four retaining
nuts. This should now be bolted to the site-mounting flange with a rigid gasket fitted between them, using the
four countersunk screws provided.
The rear flange is then offered up to the front flange on to the protruding studs, taking care that the ‘O’ ring seal
on the flange locates smoothly into the central aperture. This is then re-secured by the four nuts that screw
down onto the adjustable flange. The arrangement should now appear as in Figure 6.
OPS.086 Issue : B Rev. : 1 Date : 11/8/10 Doc. i/d : 0086/6 Ref. : 080047