Fouling mitigation

The characteristics of different fouling mechanisms determine appropriate mitigation methods to employ. Thus, it is important to understand what type of fouling occurred and identify what methods to apply. In the end, the key to success for fouling mitigation is to determine the most effective method(s) to deal with the root causes of the fouling problem. 

In general, there are four kinds of methods, namely, chemical, mechanical, operational, and process conditions based methods. These methods are briefly reviewed as follows  

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R. Sheikholeslami, Fouling mitigation in membrane processes. Desalination 123, 45-53 (1999). 

Bandelet, C.A. The Spirelf system fouling mitigation in refinery units. Second International Conference on Petroleum Phase Behaviour and Fouling, Copenhagen, Denmark, Aug 27-31, 2000 AIChE, Royal Danish Academy of Sciences and Letters, University of Denmark. 

In general the discussion will concern aqueous systems, largely because it is within these systems that much work has been carried out to develop suitable additives, principally for cooling water application. Because aqueous systems are common to many industries, and the potential need for suitable fouling mitigation is widespread, the financial incentive has been present to develop suitable and effective additives. The principles may be applied to other systems but it is unlikely that if the process stream is unique, a suitable additive will have been developed and tested. The development of a chemical that will restrict or prevent, a particular fouling problem may be expensive and the development cost unjustified. Under these circumstances either the deposition problem has to be tolerated or a different technique applied (see Chapters 15 and 16). 

The use of additives was initially confined to the combustion of fuel oils, presumably because the system lent itself to the injection of suitable chemicals and compounds. In more recent times the use of additives has been applied to coal combustion and at present treatment of flue gases derived from waste combustion is being developed. For instance fluidised bed combustors for waste incineration are very suitable for fouling mitigation using additives. The mixing effect of the... 

Milller-Steinhagen, H. (editor) Handbook heat exchanger fouling mitigation and cleaning technologies, Publico Publ. Essen (2000)... 

In general, it may be concluded that despite the endeavor described earlier to develop low-fouling membranes via surface modification with nanoparticles, further research is still needed to investigate the combined effects of the water chanistry, the nature of the nanoparticles, and the coating conditions on the modified-manbrane performance and fouling mitigation. Also, careful control and monitoring of the nanoparticles released from the modified membranes are necessary to minimize potential environment (eco) toxicity effects (Tiede et al. 2009). 

Bae, T.H. and Tak, T.M. 2005. Effect of TiOj nanoparticles on fouling mitigation of ultrafiltration membranes for activated sludge filtration. /.MemfeSci. 249 1-8. 

Heat exchanger fouling costs a lot of money for process plants. It is essential to determine the root causes and find appropriate methods for fouling mitigation from fouling prevention to exchanger cleaning cycle optimization. 

Advanced heat transfer technologies. These technologies have two features for fouling mitigation one is to increase turbulent flow while the other eliminates dead flow regions. Some of the technologies include ... 

When a heat exchanger is severely fouled, one needs to know the root causes. For example, it could be caused by low velocity or type of crudes or else. Identification of root causes lead to determination of the most appropriate fouling mitigation and cleaning method. 

PUTTING ALL TOGETHER—A PRACTICAL EXAMPLE OF FOULING MITIGATION... 

The ultimate goal for fouling mitigation is to select the most cost-effective method to provide the best exchanger performance. To achieve this overall goal, a systematic method is discussed (Figure 7.6), which can identify the root causes... 

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