- Low Cost
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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.
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.
= cell output, Millivolts
R = gas constant
F = Faraday's constant
(02) = Partial pressure of sample gas
Pr (20.9) = Partial pressure of reference air
C = Cell constant
T = Absolute Temperature
% v/s output (mv) Relationship
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
mA isolated output or
isolated output for
0-10% O2 or 0-21% O2
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.
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.
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.
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.
Oxygen measurement is on a 'wet' basis and takes into account moisture.
This gives the actual free oxygen available in the gas.
The ( Calibration facility not available for the heaterless probe )
probe used is the direct insertion 'in-situ' type and also facilitates
The output from the analyser is suitable for use with indicators, recorders,
controllers and data loggers etc.
By-pass version of model ACE 2000 suitable for temperatures upto 1000°C.
probe shields and materials of construction for harsh, erosive or corrosive
Auto-purging facility for filter on request.
Enclosure for hazardous area on request.
(Prgrammable 750°C to 843°C)
mV @ 843°C
||34.1 mV thermocouple
|1.5 to 3.5 ohms
||4 to 5 years
O2 or ± 1% of reading (for heated probe)
0.1% O2 or ± 3% of reading (for heaterless probe)
|Cell speed of
||less than 3 seconds
| Resolution sensitivity
||10 to 760°C
Max (for heated probe)
650°C to 1600°C (for heater less probe)
||0°C to 50°C
||35 to 42 ohms
AC ± 10%
230 V AC Optional
3 feet, 6 feet
or 9 feet depending on duct dimension
|0.4%, 2% and
O2 Balance N2
0-20 mA (Linear)
INNER PROBE ASSEMBLY
( add suffix1.5, 3,6,9 to indicate size)
Tube 1.5 (add suffix 1.5, 3)
Conductor (add suffix1.5, 3,6,9 to indicate size)
( clamps, bush, spring etc. )
filter with cement
Metal Filter with Cement
Shield Assembly (add suffix 1.5,3,6,9)
Micro Processor Electronics
| Mother Moard
for 230 VAC)