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- Low Cost
- Assured
Service Back - Up
- Indigenous
Oxygen
in flue gas analysis is the simplest and least expensive basis for combusion
control and can return as much as 90% potential fuel saving provided a
rugged accurate oxygen sensor is employed. The importance of minimising
excess air is that for each 1% reduction of oxygen in the stack can give
a 2% fuel saving.
The Model ACE 2000 is an " in-situ " on-line oxygen analyser
package characterised by its robust construction & designed to measure
Oxygen concentration in the flue gas from the combustion processes.
Typical application include industrial power and process boilers, refinery
process heaters, oxygen enrichment systems, wind boxes, incinerators and
air pre-heater leakage. It can be used for moisture analysis.
Each
analyser includes Oxygen sensing probe, protective support shield, 6 metre
cable, electronics package, with reference air set and calibration gas
rotameter, adaptor plate and accessories.
The heart of the systems is the Zirconia Sensor, which when maintained
at elevated temperatures gives an output (based on Nernst equation) which
is a function of the gas constant, the absolute temperature, Faraday's
constant, the natural logarithm of the ratio of the partial pressure of
oxygen on the two sides of the cell.
This means if the temperature is held. Constant and air ( 20.9% oxygen
) is used as reference air, the output becomes the inverse logarithm of
the partial pressure of oxygen in the measured gas.
emf
= cell output, Millivolts
R = gas constant
F = Faraday's constant
Ps
(02) = Partial pressure of sample gas
Pr (20.9) = Partial pressure of reference air
(Ambient Oxygen)
C = Cell constant
T = Absolute Temperature
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Oxygen
% v/s output (mv) Relationship |
Output
(mv)
The cell is encomposed by a heat shield assembly which allows the sample
gas to diffuse through the ceramic filter and also conserve and maintain
the requisite temperature. A v-deflector below the filter prevents particulate
matter from the flue gas to directly impinge on the filter and retards
clogging on the side.
The hollow of the zirconia cell houses the inner probe assembly which
consists of a heater, a thermo-couple, a platinum conductor. The heater
and thermocouple form the part of the temperature control circuit which
maintains a temperature of 843°C (34.1mv) in the vicinity of the cell.
The heated temperature is programmable from 750°C to 843°C. The
platinum conductor carries the positive signal from the cell to the terminal
strips. The negative of the cell is body ground. In case of the heaterless
probe, the process temperature itself activates the Zirconia Cell bits
range operating temperature 650°C to 1600°C.
To meet the varying stack diameters probes are available in sizes ranging
from 18" , 3' , 6' and 9'. The probes are bolted and mounted within
a support shield which gives physical protection to the probe.
The Micro - Processor based Electronics is housed in a rugged IP 65 (weather
proof) enclosure. The electronics can be mounted close to the probe or
in the Control Room with suitable cabling. The electronics is capable
of giving
- 4-20
mA isolated output or
- 0-20
mA
isolated output for
0-10% O2 or 0-21% O2
- Sensor
used is a solid Zirconia Oxide electroyte with a high speed of response
and is ideal for closed loop control. The sensor is ruggedly built and
does not experience mechanical and thermal shock like other cells in
the market, it is also easily replaceable.
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The sensor is suitable for process temperatures upto 760°C and the
sensitivity of the cell increases logaritmically when oxygen decreases.
These features make the sensor suitable for any fuel and also useful
for measuring low oxygen levels.
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Electrodes are self protected in the presence of sulphur or reducing
atmopheres. This provid long life for sensing element even in the presence
of sulphur and reducing atmospheres.
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In the absence of a sampling systems, the maintenance downtime is reduced
drastically. The rapid, accurate and reliable measurement paves the
way for significant fuel savings and enhanced safety.
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Oxygen measurement is on a 'wet' basis and takes into account moisture.
This gives the actual free oxygen available in the gas.
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The ( Calibration facility not available for the heaterless probe )
probe used is the direct insertion 'in-situ' type and also facilitates
on-site calibration.
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The output from the analyser is suitable for use with indicators, recorders,
controllers and data loggers etc.
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By-pass version of model ACE 2000 suitable for temperatures upto 1000°C.
- Special
probe shields and materials of construction for harsh, erosive or corrosive
atmospheres.
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Auto-purging facility for filter on request.
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Enclosure for hazardous area on request.
Range
of measurement |
0-10%
0-21% |
Sensing
Element
Temperature Operating
|
843°C
(Prgrammable 750°C to 843°C) |
Thermocouple
mV @ 843°C |
34.1 mV thermocouple
output |
Thermocouple
Resistance (Cold) |
1.5 to 3.5 ohms |
Expected life
of cell |
4 to 5 years |
Oxygen
indication accuracy |
0.1%
O2 or ± 1% of reading (for heated probe)
0.1% O2 or ± 3% of reading (for heaterless probe) |
Cell speed of
response |
1 millisecond |
System speed
of response |
less than 3 seconds |
Resolution sensitivity
|
0.01% O2 |
Process temperature
|
10 to 760°C
Max (for heated probe)
650°C to 1600°C (for heater less probe) |
Ambient Temperature
|
0°C to 50°C |
Heater Resistance
(cold) |
35 to 42 ohms |
Power
supply |
115v
AC ± 10%
230 V AC Optional |
Calibration Gas
Flow (In-built) |
2 LPM |
Reference air
flow (In-built) |
1 LPM |
Probe
length |
18
inches
3 feet, 6 feet
or 9 feet depending on duct dimension |
Calibration Gas
Specifications |
0.4%, 2% and
8%
O2 Balance N2 |
Isolated
Analogue
Output |
4-20
mA(Linear)
0-20 mA (Linear) |
(A)
BASIS PROBE |
2000-0A |
ZIRCONIA
SENSOR |
2000-0
AA |
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(B)
INNER PROBE ASSEMBLY |
2000-0AB |
Heater
( add suffix1.5, 3,6,9 to indicate size) |
2000-0AB1 |
Ceramic
Tube 1.5 (add suffix 1.5, 3) |
2000-0AB2 |
Plantinum
Conductor (add suffix1.5, 3,6,9 to indicate size)
|
2000-0AB3 |
Heater
Support |
2000-0AB4 |
Hardware
( clamps, bush, spring etc. ) |
2000-0AB5 |
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(C)HEAT
SHIELD ASSEMBLY |
2000-0AC |
Metal
assembly |
2000-0AC1 |
Ceramic
filter with cement |
2000-0AC2 |
Sintered
Metal Filter with Cement |
2000-0AC3 |
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(D)
MOUNTING HARDWAR |
2000-0B |
Support
Shield Assembly (add suffix 1.5,3,6,9) |
2000-0B1 |
Adapter
Plate |
2000-0B2 |
O Ring
|
2000-0B3 |
Gasket |
2000-0B4
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(E)
Micro Processor Electronics |
2000-0C |
Mother Moard
(Heated Probe) |
2000-0C1 |
Display Board |
2000-0C2 |
Transformer (Option
for 230 VAC) |
2000-0C3 |
Calibration Gas
Rotameter |
2000-0C4 |
Reference Air
Rotameter |
2000-0C5 |
Reference Air
Pump |
2000-0C6 |
Reference Air
Filter |
2000-0C7 |
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