Monitoring
Measuring carbon monoxide is the
strongly preferred detection method
for self-heating in coal storage piles
due to its more advanced warning
period over temperature.
Sensors continuously observe the
amount of methane, carbon
monoxide and oxygen in the air.
Potential hot spots will develop
close to the surface.
Fuel management system
The main goal for a power plant is to
make sure that the most economic
coal of precisely the right quality
gets to the burners to meet the boiler
requirements. The ability to
consistently deliver the right coals to
the burners can significantly reduce
fuel costs for the plant. For
intelligent optimisation of coal
burning to meet demanding power
loads, emission requirements and
cost objectives, it is important to
know what coal is being burned.
To achieve this goal, a power
plant must address three main
issues. The first is to know the
quality of all the coals purchased
and where they are located. The
second key issue, operational in
nature, is for the power plant to keep
track of all coals as they arrive and
where they are in the coal silos. The
third key issue is the ability to know
what coals are being loaded into the
day bunker, when they are and in
what quantity.
For this ESI delivered the fuel
management system (FMS). This
software package offers two operate
modes:
n
n
Replay mode: display what
happened over the past 10 days.
n
n
Monitoring mode: display the
current status.
With this, the flow of coal into
silos and day bunkers can be
accurately modelled and the tracking
of all coals onsite, from receipt to
combustion, becomes relatively easy.
In addition, the same capability can
be used to perform controlled
loading sequences into the day
bunkers to ensure that coal of a
predescribed quality is discharged at
predescribed times.
The typical manner in which
recommendations are presented to
the main control room is in sulfur
content of the coal to the expected
load demand over the next period
e.g. 24 hr. The normal operational
constraint is that the plant only
loads coal into day bunker twice a
day.
Settings and warnings
Upon entering the silo, one can
easily see if a warning or alarm
value is measured inside the silo by
the monitoring system. These values
are pre-set and depend on the coal
quality.
Safety measures
Besides continuous monitoring,
active airflow prevention is also part
of the Eurosilo fire system. The
hoppers in the bottom of the silo are
a potential entry point for air. By
installing a slide valve underneath
the reclaiming openings, air
penetration is reduced to a
minimum.
Both Eurosilos are equipped with
a nitrogen-purging system, enabling
operators to purge the whole silo,
thus enabling longer trouble-free
storage periods. The piping for this
system is embedded in a layer of
Positioning the sensors.
Coal blending with Eurosilos.
52
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World Coal
|
July 2015
