Cleaning Heat Exchangers with High- and Ultra-high-pressure Water Figure 12: 'Striped' (a) and Cleaned (b) Tubes A Figure 14: 90-degree Angled Jets for Efficient Cleaning
B
Figure 13: Rear-facing Jets
Depending on the size of tubes that need to be cleaned, you would use no bigger hoses/lances than two-thirds to three-quarters of the inner diameter of the tube. You want to make sure that enough space is left open to transfer any contamination past both nozzle and hose. When it becomes too tight, you have the danger of pressure building up and run the risk of the hose backfiring through the tube
By properly cleaning heat exchangers you can achieve both longer cleaning intervals and a much more efficient production process.
of semi-automatic cleaning is that tubes are being cleaned twice; when the jets are going in and also when they are going out of the tube.
For hard contamination and blocked tubes, rigid lances are the better option, as these can focus all the kinetic energy towards the front.
The cleaning of heat exchangers mainly requires special nozzle constructions: rotating nozzles (tube spinners, FRs and banshees) and unpluggers. Having all forward-facing jets (orifices) in the nozzle produces better cleaning because all the energy is directed against the fouling.
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(‘hydraulicing’). By using stingers, you prevent flex hoses potentially turning around in the tube. When using a nozzle or hose which is too small in comparison with the tube diameter, you will lose capacity of flow. Therefore, a good combination of nozzle and hose is required for optimum results.
Conclusion
Heat exchangers are prone to fouling and can therefore lose their efficiency. This in turn has a negative effect on the running costs of any production process. Due to rising energy costs it is becoming more important to run processes more efficiently. By properly cleaning heat exchangers you can achieve both longer cleaning intervals and a much more efficient production process. n
HYDROCARBON WORLD – VOLUME 6 ISSUE 1
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