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Title:
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Early Agglomeration Recognition System - EARS: From bench-scale testing to industrial prototype
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Author(s):
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Korbee, R.; Lensselink, J.; Ommen, J.R. van; Nijenhuis, J.; Gemert, M. van; Haasnoot, K.
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Published by:
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Publication date:
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ECN
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1-10-2004
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ECN report number:
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Document type:
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ECN-C--04-052
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ECN publication
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Number of pages:
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Full text:
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51
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Download PDF
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Abstract:
This report describes the
development and testing of a method to monitor and control agglomeration
in a bubbling fluidised-bed combustor. EARS - for Early Agglomeration
Recognition System - detects agglomeration in an early stage and allows
operating staff and engineers to control the agglomeration process and
prevent defluidisation.
The project EARS-I was carried
out between 15.11.2001 and 29.02.2004. The development was a joint effort
of the Energy research Centre of the Netherlands and the Technical University
of Delft. The project was carried out together with partner Essent Energie
Productie, who installed and hosted the testing of the EARS system in
a wood-fired, 80 MWth bubbling fluidised-bed combustor in
Cuijk, the Netherlands.
EARS was extensively tested on different bench-scale
facilities. EARS was demonstrated to be sensitive to changes in the
size distribution as well as the stickiness of particles in the fluidised
bed. Both are key parameters in bed agglomeration. For the bench-scale
facility a method was developed to control the level of agglomeration
in a fluidised bed by means of bed material make-up.
A prototype of the monitoring and control system
was tested in the Essent wood-fired, 80 MWth bubbling
fluidised-bed combustor in Cuijk, with the aim to develop solutions
for typical industrial aspects such as scale-effects, disturbance of
other process signals, equipment issues, and process control. A positive
relation was found between the S-values calculated by EARS and
the mass fraction of a particle size considered to be an indicator for
the level of agglomeration in the bed. Under industrial conditions EARS
is not disturbed by up to 10% variations in the fluidising velocity
or bed height. The reliability of EARS was further increased by various
techniques, e.g. filtering. Prior to a plant stop, EARS was tested
and used to support a reduction of the sand make-up rate. A decrease
of about 35% was established with minor changes in bed agglomeration.
EARS successfully detected the observed changes in the particle size
distribution.
Recently,
a follow-up project EARS-II was initiated to finalise the design for
bubbling fluidised-bed systems and to develop a prototype for circulating
fluidised-bed systems.
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