power was transferred to the grid in
December 2013.
The power plant is estimated to
use approximately 240 tph of coal at
full load. Coal is sourced through
long-term coal supply contracts and
delivered via the Datteln-Hamm
canal.
Eurosilo was awarded the contract
for constructing the coal storage silos
for the plant.
Coal handling
The plant requires about 2 million tpy
of coal. The coal is sourced from
various mining regions around the
world and delivered to the
Port of Rotterdam by bulk‑carriers.
From there, it is loaded onto barges
(typically four per day) and delivered
to the plant.
The coal is unloaded using cranes
at the plant-owned port and is stored
dust-free in two silos with a 200 000 t
total capacity – enough to operate the
plant for approximately 30 days at
full load. Fugitive dust emissions are
virtually eliminated through the use
of fully enclosed conveyor systems.
A possibility is to convey coal
directly from the cranes via a bypass
to the four day bunkers, where it can
be burned on the same day in the
boiler.
The coal is conveyed from the silos
to four day bunkers that can hold
800 t each in the steam generator
building. It is then pulverised and fed
into Lünen’s 70 m tall boiler.
Coal can be, in case of emergency,
conveyed from the Eurosilos to an
emergency loadout area, where it can
be treated and e.g. afterwards
transported to be re-used.
ESI Eurosilo has carried out the
maintenance and inspections for the
first 2 yr of Eurosilo operation.
As a result of this, experience and
insight was gained in daily operations
of coal silos in general and of the
Lünen installation in detail. This
enabled all parties to gain and share
experiences and optimise the daily
use, operation, maintenance and
inspections of the Eurosilos – building
a close cooperation between parties
and enabling the maintaining of high
standards of working and the
implementation of ideas together.
Coal silos: the details
Why Eurosilos?
Table 1 shows a summary of
comparisons between options for
enclosed storage systems for the coal.
Eurosilo advantages
The Eurosilo advantages for the
Lünen coal-fired power plant were as
follows:
n
n
Totally enclosed storage.
n
n
State-of-the-art technology.
n
n
Small footprint.
n
n
Fully automated system.
n
n
Meeting the most stringent
environmental protection
requirements (avoids emissions
of respirable dust)
n
n
Coal blending (the values of the
process parameters and the boiler
efficiency depend on the mixture
of coal being burnt in the boiler).
n
n
Lower total cost of ownership in
comparison to other comparable
systems.
Blending of coal
Fuel cost reductions are achieved by
delivering coal of a predetermined
quality to the burners at all times. If a
power plant adopts a dynamic
approach to coal blending (i.e. the
as-fired blends change continuously
to adjust to changing conditions, such
as load, emissions, capacity, coal
availability and expected coal
deliveries), the power plant can
significantly reduce fuel-related costs.
Thus operational flexibility is a
core requirement for cost-effective
power plant operation. To keep
emissions low and to keep an
optimal boiler handling, the mixture
of the coal has to be optimal. This is
achieved by blending, keeping the
ratio from the two silos in a
predetermined rate.
Coal: monitoring,
measuring, managing
Fundamentals for
monitoring
Upon the arrival of the coal, the
temperature of the coal in vessel is
measured by temperature lance and
infrared camera.
Methane, carbon monoxide and
oxygen sensors are present in the
basement and at the overhead
bridge. Depending on the amount of
carbon monoxide (ppm), monitoring
can be intensified and/or preventive
actions can be taken.
Table 1. Comparison of systems
Eurosilo
Circular (dome) storage
Longitudinal (A-frame) storage
Footprint
The most compact system
2 x larger footprint
3 x larger footprint
Filling
Minimal segregation by equalising
auger
Segregation
Segregation
Operation
Fully automated
Partly automated
Partly automated
Oxygen access
Limited
Severe
Severe
Nitrogen purging
Possible through bottom piping
Not possible
Not possible
Structure
Simple slip form
Complex concrete wall
Standard A-frame shed
Coal monitoring
Continuous monitoring by CO Only by infrared
Only by infrared
Fuel management
Fully automated
Partly automated
Partly automated
Dust emissions
None
None
None
Percolation pollution
None
None
None
50
|
World Coal
|
July 2015
