ECN publication
Karakterisering van een microfiltratie-membraaninstallatie: opzet, uitvoering en analyse van experimenten aan DWT-installatie
Published by: Publication date:
ECN 1-7-1999
ECN report number: Document type:
ECN-I--99-010 Other
Number of pages: Full text:
136 Download PDF  

Identify and implement measures to improve the energy efficiency of theoperation of a filtration process based on inorganic membranes is the objective of the research project 'Advanced Process Control of a Membrane Installation'. As a first step in this project, experiments were carried out in the micro-filtration membrane installation which is used by the Decontamination and Waste Treatment (DWT) facility of ECN/NRG (Netherlands Energy Research Foundation/Nuclear Research and Consultancy Group) in order to process contaminated water from laboratories and nuclear facilities. Additional temperature and pressure sensors were installed and the data acquisition system was extended. The fixed speed circulation pump of one module has been replaced by a variable speed pump. The cross-flow velocity was varied from 4.5 to 6.3 m/s and the transmembrane pressure (TMP) from 0.18 to 0.37 MPa. Practical issues relating to the control of the permeate-retentate ratio have been clarified. The module temperature appears to be a reliable measure for the membrane filtration efficiency. Discrepancies between a simplified model and the experimental data require additional attention. Preliminary results indicate that yield can be increased by increasing the TMP without causing a detrimental compacting of the cake on the membrane surface; the membrane resistance is virtually not affected. The beneficial effect of an increased crossflow velocity on membrane fouling and delayed cake formation cannot be substantiated by the scoping experiments. The large variation in feedwater quality obscured the experimental results, and therefore additional attention on representative feedwater quality conditions is needed. The preliminary results indicate that a reduction of the crossflow velocity from 6.0 m/s to 5.0 m/s can result in a substantial increase of the energy efficiency (at least 25%) without affecting yield. 36 refs.

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