APPLICATION NOTE
Process Analyzers for Stable, Long-Term Measurement of
High-temperature, Dust-laden Gases
Industry: Cement
Product: Gas Analyzers
Introduction
Cement is made by heating calcareous and argillaceous
materials to a temperature between 1100 and 1500 °C. As this
process uses massive amounts of energy, various energy
saving measures are taken, including the measurement of
oxygen concentrations in exhaust gases to control combustion.
To protect the environment, electrostatic precipitators (ESPs)
reduce dust emissions and analyzers measure concentrations of
nitrogen oxides (NOx), sulfur dioxide (SO2), and other pollutants.
Analyzers installed for this purpose are expected to provide
stable, long-term performance even under harsh process
conditions. Yokogawa process analyzers can be used to
measure O2 and CO at the upper end of a kiln or at the outlet of
a flash furnace, where high-temperature, dust-laden gases flow.
They can also be installed at the outlet of an ESP to monitor dust
concentrations and optimize efficiency, and in a smoke stack to
measure NOx, SO2, and O2.
Expected Benefits
– Measures gas concentrations and dust concentrations in
cement plants
– Reduces operating costs
Sample Conditions at Measurement Points
Measuring Point
1: Upper End
2: Precalciner
of Kiln
Condition
Outlet
3: Suspension
4: ESP Outlet
5: Stack Inlet
Flash furnace
Outlet
Measured Components
O2+CO+CO2
O2+CO+CO2
(O2)+CO+CO2
Dust
Gas Temperature (°C)
1050 to 1200
600 to 850
350 to 400
100 to 130 (MAX.200) 100 to 130 (MAX.200)
Amount of Dust (g/Nm3)
200
100 to 200
60 or less
0.1 or less
0.1 or less
Pressure (kPa)
-0.2 to 0.5
-3 to -2
-0.2 to 0.5
-5 to -3
1 to 2
2 to 4
2 to 4
3 to 5
3 to 5
3 to 5
0.2 or less
0.2 or less
0.2 or less
0.2 or less
0.2 or less
23 to 26
9 to 11
23 to 30
9 to 11
23 to 30
9 to 11
23 to 30
10 to 15
23 to 30
10 to 15
Remaining
0.1 or less
0.01 or less
Remaining
0.1 or less
0.01 or less
Remaining
0.01 or less
0.01 or less
Remaining
0.01 or less
0.01 or less
Remaining
0.01 or less
0.01 or less
Water-washing/
cooling probe
water ejector type
sampling system
Water-washing (*1)
probe
water ejector type
sampling system
Water-washing
probe
water ejector type
sampling system
Model DT450 dust Model SG750
monitor (refer to
stack gas analyzer
AN 10K02H01-01E)
NOX+SO2+O2
Gas Component (vol%)
O2
CO
CO2
H 2O
N2
SO2
NOX
Main measurement
system configuration
Model IR200
Model IR200
Model IR200
Infrared gas analyzer Infrared gas analyzer Infrared gas analyzer
(*1) Water-washing/cooling
probe is recommended,
when sample gas
temperature ≥ 800°C.
NOTE:
1 to
5 represent the measuring points in the summarized process overview for a Cement Plant.
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AN 10Y02H01-01E
All Rights Reserved, Copyright © 2006, Yokogawa Electric Corporation
APPLICATION NOTE
Process Overview
Exhaust
Clay
3
4
2
Limestone
Exhaust
: Material flow
: Gas flow
ESP
5
Cyclone
Limestone
dryer
4
Burner
ESP
Flash furnace
r
Clay drye
Cooler exhaust
Water
Stack
Stabilizer
Rotary kiln
Bucket
elevator
Mill
Burner
1
Clinker cooler
Clinker
Cement Manufacturing Process: Raw materials such as calcareous and argillaceous materials are dried, blended, and pulverized
in a mill to create powdered material. The powdered material is preheated and decarbonated in a suspension preheater and flash furnace,
and calcinated in a kiln to produce clinker. The clinker is cooled, mixed with gypsum and ground in a finish mill to produce cement.
1 O2-CO Measurement System at the Upper End of a Kiln Years of experience in high-temperature dust laden gas application
Probe should be installed so that
2 (Wet suction method for high-temperature dust laden gases)
Probe Selection
the probe head points upward at
Cooling
1
3
water outle
an angle of 5 to 15° to the horizontal.
: Water-washing/
t Coolin
g
Wa
Rc
2
ter in
1/2
Washing Water Out
cooling probe
Probe (see right figure)
Contact Output
Purging Status
Low Level of
Cooling Water
Power
Supply 100V AC, 50/60Hz
Solenoid
Valve
P
Cooling Water
Return
Sample Gas Out
Sample Gas Vent
Water In
Drain Out
To Analyzer
Panel
Mounting fla
nge
Manifold
Details of part A
Drain Pot
Flow Switch
Sampling System with Air Blowback Function
(Separate analyzer panel type)
Can be used for sample containing dust of
up to 1 kg/Nm3.
Water In
Drain Out
Dehumidifier
O2 Analyzer
Bubbler
3 : Water-washing probe
Heter
B
Power Supply
Sample
Gas in
Output
(O2 Analyzer)
Output
(CO Analyzer)
CO Analyzer
Air Purge
Support pipe
Rc1/2
Mounting flange
Details of part B
ZERO
Wash water
inlet
Rc1/8
Gas drain outlet
Sample Gas in
SPAN
Washing water
Sample gas + Wash water + Dust
SPAN
Inst Air In
Wash head
5 : SG750 stack gas analyzer
Increased stability and reliability achieved in combination
with a sampling system with excellent maintainability
Scale
For positioning the wash head
Sample Gas In
Thermostat
Wash water
in
Rc1/2
Rc1/8
Sample gas
+ Wash wa
(+ Dust) ou ter
t (to Ejector)
Wash water diffuser
Sample Gas Out
positioning
Cooling water return
Cooling water intake
Wash water intake
Sample gas + Wash water + Dust
Jet wash
Piping distance: 15 m maximum
a
Note: When measuring only O2 concentration
at point 3 , ZR22G/ZR402G zirconia
oxygen analyzer can be used.
Sample gas
in
(+ dust)
Inst. Air In
T
a
Scale
For wash he
ad
A
Cooling Water Out
Sample
Gas In
Probe
Teflon
Tube,
Φ10/Φ8
Switch
Box
Air Inlet
e
or
rm
˚o
15
*1
Sampling Module
3-Way
Solenoid Valve
Pump
Sample
Gas Inlet, Rc 3/8
Needle
Valve
Gas
Conditioner
Flow Checker
NO2/NO
Converter
30 kPa
0.5L/min
Atmospheric
Air
*1
Sampling System
2-Way
Solenoid Valve
Membrane
Filter
Electric
gas cooler
Solenoid
Valve
Infrared
Analyzer
CO, CO2
Membrane Filter
Infrared
Analyzer
NO, SO2
ZERO
NO
SO2
CO2
CO
O2
Pressure Regulator
Zirconia
O2
Analyzer
Air
NO
/N2
Drain
Filter
Regulator
30 kPa
Instrument Air Inlet
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AN 10Y02H01-01E
All Rights Reserved, Copyright © 2006, Yokogawa Electric Corporation
4th Ed: Jan.2011 (YK)
SO2
/N2
CO2
/N2
CO
/N2
O2
/N2
Standard Gas
Outlet