ABB ProKiln GAC400 Operating Instruction page 68

68 ProKiln GAC400 PROBE GAS SAMPLING SYSTEM | OI/GAC400-EN REV. A
... 9 Operation
... Monitoring automatic mode
Power failure
Failure of the general mains power leads to immediate
retraction of the gas sampling probe out of the kiln. After
switching the power supply back on, the display and operating
unit boots and the sampling system switches to manual mode.
To resume normal measuring operation, you must manually
insert the gas sampling probe into the kiln and then switch to
automatic mode (see Commissioning on page 56).
Damage
The probe (probe tube and filter) may get damaged in the
following situations:
• if raw material falls on the probe
• if too much material adheres to the probe tube (excessive
build-up)
• if tire parts or bullets hit the probe tube
• Kiln rotation caused mechanical impact from material or
kiln lining
• if red-hot material flows over the probe
• if aggressive combustion residues condense on the probe
tube and filter material
• if the probe tube material is worn-out by high flue gas
speeds (particularly critical at flue gas speeds > 20 m/s)
Note
The manufacturer offers no warranty for such damage.
Special considerations for SO
SO measurements are very useful to monitor re-circulation of
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volatiles in the kiln system. ABB recommends the measurement
of SO with a suitable continuous gas analyser, in order to
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increase kiln performance and reduce lining wear inside of it.
The following problems may occur when measuring SO
• if the gas sampling hole on the tip of the probe clogs up
with combustion particles, an increasing amount of SO
absorbed,
• if a layer of rust particles builds up on the filter unit, SO
will also be absorbed as the sample gas travels to the
analyser,
• if the sample gas condenses in the sample gas tube, part
of the SO dissolves in the condensation, which in turn
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decreases the SO concentration measured in the
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analyser.
In the above-mentioned cases, the falsification of results will be
even more severe, the lower the concentration of SO
measurement
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:
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is.
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Maximum reliability of SO
• when the gas sampling hole on the probe tips is
completely open (i.e., not clogged up with rust particles),
• immediately after blow-back.
Due to the propensity of rust particles to form incrustations on
or inside the probe gas sampling system that may result in
absorption of SO , the manufacturer offers no warranty on such
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measurements.
In order to achieve representative results when measuring SO
follow these steps:
• Make sure there are no cold spots in the probe sample
system and gas analyser system that could wash-out the
SO
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• Have a suitable SO
analysers in optimum operation condition according to
manufacturer's specification
• Measure the SO
minutes after a probe cleaning (blow-back) has been
performed.
• Make a trend curve connecting the measured SO
over time based on the probe cleaning signal.
• Adjust the probe cleaning sequence to shorter intervals if
you need to make more frequent SO
• Frequently remove dust, rust and any other materials
which could affect the measured SO
If safe operation is no longer possible
If it can be assumed that safe operation is no longer possible,
the probe gas sampling system must be taken out of operation
and secured against being started up again.
It can be assumed that safe operation is no longer possible:
• if the sampling system is visibly seriously damaged,
• if the sampling system is no longer operational,
is
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• after prolonged storage under adverse conditions,
• after severe transport stress.
2
measurement is given,
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analysis setup of continuous gas
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process concentration in the first 1-2
2
measurements
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values.
2
,
2
values
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