INTRODUCTION
OPSIS is a Swedish company which develops, manufactures and supplies total solutions for Ambient Air Quality Monitoring, Stack
Emission Monitoring and software tools for Air Quality Management.
Founded 1985
OPSIS is represented world-wide, with internationally accepted and approved products.

OPSIS PRODUCTS

MAJOR APPLICATION AREAS

QUALITY AND ENVIRONMENTAL
MANAGEMENT
ISO 9001
• Quality
ISO 14001
• Environment
ISO 17025
• Calibration laboratory
• Ackreditation laboratory

OPSIS CEM SOLUTIONS

CEM/PROCESS SOLUTIONS
UV/IR DOAS IN-SITU SYSTEMS
TUNEABLE DIODE LASER IN-SITU SYSTEMS
DILUTION EXTRACTIVE SYSTEMS

LASER DIODE ANALYSER
Features :
• Fast response time (~ 1 sec)
• Multiple paths
• Multiple gases
• Analyser separated from Emitter/Receiver
• Long fibre lengths (< 1 km)
• Low detection limits

SYSTEM OVERVIEW, CEM
LD500
EM060L
Cabinet
Laser fibre optical cable (< 1 km)
Communication cable (< 2 km)
RE060L

Emitter Receiver with detector and A/D converter
SYSTEM DESIGN
Stack Digital signal
LD500 analyser
Ramp generator Diode laser
Internal Detector
Reference cell
Beam switch
”Zero” signal / ”Reference” signal
Wavelength/scanning control signal
Beam splitter CC
Communicatin Interface
”Measurement” signal
PC Processor
LD500

TUNING THE LASER
NIR semiconductor laser
Controlled variations in temperature will ”tune” the diode lasers output wavelength.
The temperature variations are created by applying a sinus shaped drive current with a frequency of 1 kHz, with a temperature accuracy of 0.001 C˚

Absorbance
100%
O
2
HF
ABSORPTION SPECTRUM
Laser is tuned around one or a few absorbtion lines,
Scanned range is typically less than 1 nm
H2O
0 %
1.25 um
1.35 um
LD500

SPECTRA HANDLING
”Zero” signal
”Measurement” signal
Resulting spectrum
The scanned spectra are resolved into 1000 channels
Measurement spectrum is divided with the Zero spectrum to obtain the resulting spectrum and to eliminate noise generated by the laser

I
1
I
2
C =
Ln ( I
1
α
1
/ I
2
– α
2
) x l
+ Line Widening effects due to temperature & partial pressure
The cross section area of the obtained spectrum is used to calculate the concentration by use of Beer
Lamberts law, compensated for line widening effects

RESULTS
Results are presented as :
Concentration ( typically % (vol) , ppm or mg/m3 )
Standard deviation ( typically ppm or mg/m3) , based on the average standard deviation over the evaluated number of channels in the measured cross section spectrum
Light level, expressed as dB , proportional to the amplification required on the detector.

MEASURING TEMPERATURE
Absorption lines
Temperature can be measured by studying the proportions and relations of the absorption lines, as they change with temperature

HARDWARE

EMITTER

RECEIVER

PERFORMANCE
Gas Typical
Range
Detection limit
( 10 metre)
CO2
CO2
O2
H2O
CO
CO
0-100% 0.01%
0-10000 ppm 0.5 ppm
0-21%
0-100%
0.01%
0.01%
0-100% 0.01%
0-10000 ppm 10 ppm
CH4
CH4
NH3
HCL
0-100%
0-10 000 ppm
0-1000 ppm
0-1000 ppm
HF 0-50 ppm
Temperature 0-1500 ° C
0.01%
0.2 ppm
0.05 ppm
0.05 ppm
0.005 ppm
+/- 5 ° C

CEM/PROCESS EXAMPLE
(maximum 8 paths )

Emitter
Optical fibre cable
Laser Module
Laser Module
Laser Module
LH51n
24 VAC
Multi
Communication fibre cable
SIGNAL LAYOUT
Receiver
A/D
+/-15 VDC
+6 VDC
110/220-240 VAC
RS232
Computer
PC104
Hard Disk
Floppy Disk
LCD
Keyboard
Modem
+/- 15VDC
PM020 CM002
110/220-240 VAC
IM001 OM001
DM016
0-10VDC
0/4-20 mA
0/4-20mA Status
I/O
Ioman Signal Handling System ( Optional)
+/- 12VDC
+5 VDC
LD500 Analyser
110/220-240 VAC

LH 514 Laser Module
Typical Applications:
• Process monitoring
• Tunnel monitoring
• Steel plants
• Cement plants
CO , CO2 , H2S

O2 AND TEMPERATURE
LH 515 Laser Module
Typical Applications:
• Furnace control
• Steel process
• Smelters
• Incinerators

LH 512 Laser Module
Applications:
• Waste Incinerators
• Chemical industry
• Acid Scrubbers
HCL

LH 513 Laser Module
Applications:
• DeNO x
Applications
• Fence-line monitoring
• Fertilizer industry
NH3

IPP-TAIWAN: 20 g/m3 dust , 300 degrees C, 4 metre path
ER60L-Receivers Power supply for detector

ER60L-Emitters

LH 516 Laser Module
Applications:
• Petrochemical plants
• Coke ovens
• Landfill
CH4

LH 511 Laser Module
Applications:
• Aluminium smelters
• Fence line monitoring
• Chemical industry
HF

POTROOM MONITORING

EXAMPLE , HF DATA
Pot activities

CALIBRATION
Calibration cell
Standard gas
Emitter Calibration bench
Receiver
Analyser
LD500

CALIBRATION EQUIPMENT
Rotameter
(flow control)
Calibration gas
LD500
Receiver
Emitter
Calibration bench Gas valves

COMMUNICATION ALTERNATIVES
Plant DSC/PLC
RS232, Alternative 4 ( Cactus, ABDH, ModBus, Siemens 3964R, Comli)
Enviman ComVisioner
Analyser
RS232, Alternative 3 LAN
RS232, Alternative 1
RS232
RS232, Alternative 2 +3
+/- 15VDC CM
IM001 OM001 DM016
110/220-240 VAC
0-10VDC
0/4-20 mA
0/4-20mA Status
I/O
Ioman Signal Handling System ( Optional)

STEEL PLANT APPLICATIONS

EMISSION MONITORING
Vizag steel plant Visakhapatnam,
India,using Opsis analysers for monitoring NOx and SO2 in 15 stacks

REHEATING FURNACE
•
Purpose
–
Used by all steel processing plants to heat material before treatment
–
Often crucial to meet right temperature
–
Can replace soaking pit
•
Operation
–
Oil- or gas burners heat the oven compartment
–
Desire to use natural- or waste gas
–
Comparably low dust level

REHEATING FURNACE
•
Measurements of interest
–
Oxygen : decrease level to reduce fuel consumption and oxidation but keep sufficient levels for effective combustion
–
Carbon Monoxide: as indicator of incomplete combustion
–
Temperature: Important for correct process
•
Problems to overcome
–
Tendency of smoke formation at low oxygen levels
–
Hot environment

MONITORING AFTER REHEATING FURNACE
TAIL GAS DUCT
SLABS
REHEATING FURNACE
AR600 ( NO,NO2,NH3)
LD500 ( O2)
CORUS STEEL installation in European Plant
Installed early 2007
Measuring NO,NO2,NH3,O2
Temperature is approx. 450 degrees C

CORUS STEEL MEASUREMENT DATA

CORUS STEEL MEASUREMENT DATA

POSCO STEEL, SLAB REHEATING
FURNACE
= measurement location for Oxygen d
SLAB
1100 ° C 1200 - 1300 ° C 1100 ° C
Charging zone Preheating zone Heating zone Soaking zone d
: Open-path height from SLAB surface 30 – 40mm
Cross section = 13 metre

MODIFICATIONS MADE FOR REHEATING
FURNACE APPLICATION
Wall
Laser beam
Max 85 degrees C
Max temperature , 40 degrees C
RC101L+ PS
RE060L-T
Furnace duct
1300 degrees C
LD500
CF120, max 1000 metre
Room temperature ( 15-30 degrees C)
Max 50 metre cable
50mm diam hole
Instrument air
New modifications:
1.Moved out electronic cards from RE060L, to a separate enclosure that can be installed at a distance up to 50 metre
2. Improved laser with 3 mW output compared to old laser with 0.1 mW, allows better light levels and handling of high dust levels
3.Opsis R&D department has installed a high temp heated measurement chamber which allows test environments up to 1300 degrees C .This has resulted in improved spectra handling and evaluations

MONITORING CO AND HYDROCARBONS
Unknown compounds, most probably hydrocarbons.
Can be presented as unknown compound X,Y,Z etc , if of any interest for the user.
CO spectrum ( blue) recorded in reheating furnace, compared with factory spectrum( red/blue)
Absorption is too a large extension covered by unknown absorption lines, most probably hydrocarbons , making it difficult to reach very low detection limits for CO ( which also have weak absorption due to temperature induced line widening effects)
R&D is ongoing to overcome the problems and to reach better performance for CO

OTHER POSSIBLE APPLICATIONS
Blast furnace off gases ( CO,CO2)
LD converter off gases (CO,CO2,O2)
Coke oven off gas/leaks ( CH4,CO,O2,BTX)
Sinter plant off gas/waste gas ( H2O,HF,HCL)

Paths
Up to 8 paths OPSIS
LD500
Principle
Separate TDL
Optical cable
Multiple TDL (4)
Switching TDL
TDL in the emitter Only 1 path NEO
SIEMENS Separate TDL
Optical cable
Up to 3 paths
Signal handling Comments (+/-)
I/O up to
255channels
RS232 with several ind.protocols
Modem
+Multiple path (max 8)
+Multiple gas ( max 4)
+Also includes logger (IO256)
+Built-in cal.check
I/O
RS232
I/O
RS232
+/-Simple system
- Limit in distance
-TDL on the duct
-Only one path
+Multiple paths
+Built-in cal.check
BOREAL Separate TDL
Optical cable
Up to 8 paths I/O
RS232
+Multiple paths

CONCLUSIONS
Opsis LD500 TDL system features:
• Fast response time (~ 1-10 seconds)
• Semiconductor laser = reliable, long life time
• Multiplexing of up to 8 paths ( = cost effective solutions)
• Multiple gases ( HF,CO, CO2, H2O ,HCL,NH3, CH4…..)
• Up to 4 different gas compounds in the same analyser
• Long fibre cable lengths (< 1 km)
• Low detection limits
• Can operate in high dust environment
• Can operate in high temperature environment
• A minimum of maintenance