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Title:
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Optimale regelstrategie voor een microfiltratie-membraaninstallatie : experimenten en procesmodel DWT-installatie
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Author(s):
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Published by:
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Publication date:
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ECN
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1-1-2000
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ECN report number:
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Document type:
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ECN-I--00-001
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Other
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Number of pages:
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Full text:
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195
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Download PDF
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Abstract:
An optimal process control strategy was designed, based on experimentsand a process model for a microfiltration membrane unit. The experiments were
carried out with one module of an operational microfiltration membrane unit
while processing contaminated water from laboratories. Therefore the quality
of the processed water represents the variety of the operational unit. The
experiments were carried out at different transmembrane pressures (TMP) and
cross-flow velocities (LSS). The cake layer formation by fouling at these
conditions and the resulting overall energy efficiency is quantified based on
an analysis of the experiments and a series of simulations. Preliminary
results indicate that permeate flow can be increased by increasing the TMP.
The preliminary results indicate that a reduction of the cross-flow velocity
(by constant TMP control) from 6.0 m/s to 4.5 m/s can result in a substantial
decrease of the specific energy consumption (at least 35%). The starting
point for the simulations was the choice of an appropriate process model for
membrane fouling. For this purpose, two models for long-term membrane fouling
were evaluated for experimental data obtained from the membrane installation
from DWT (section Decontamination and Waste Treatment of the Nuclear Research
Group (NRG) in Petten, Netherlands) during process. These models concerned,
respectively, a precipitation model and a gel layer model. The results
indicated that the gel layer model fitted best to the data of the
installation. Therefore, this model was used in the following stages of
investigation to an optimal process strategy. A series of simulations were
carried out to determine an optimal strategy with respect to minimal specific
energy consumption. Within the licensed envelope of process conditions, the
most energy efficient operating conditions were identified. Practical issues
relating to the control of the permeate-retentate ratio have been clarified.
Similarities between a simplified gel layer and the experimental data
required additional attention. 18 refs.
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