Plugging and reduced heat transfer

When being exposed to fouling, heat-transferring surfaces lose effectiveness over time due to scaling and buildup. This keeps power boilers from reaching their full potential. 

To unlock the potential of the boiler, it requires cleaning. One way that most plants around the world do this is by manually cleaning the desired area during a designated stoppage. This, however, poses a major loss in energy production.

 

In this section we present three plants that had major issues with this before implementing acoustic cleaning. Click on their name to download an in-depth case study:

• Mälarenergi, Kraftvärmet Block 6: A Swedish waste-to-energy plant that had to stop their boiler operation, to sandblast the economizer every 3-6 months.
• Sandviksverket, Växjö: A Swedish CFB boiler, fuelled by biomass, that reduced their sootblowing steam consumption by 50% in the air preheater and economizer. The acoustic cleaner also fully eliminated the need to sootblow in the catalyst.
• EEW Delfzijl, Holland; A waste-to-energy power plant in Holland that manually had to explosion clean their catalyst every other week to keep the heat exchange surfaces clean.  

Smoke tube boiler operators are also commonly affected by fouling and have to perform manual cleaning even more often than the above-mentioned.

 

Different types of acoustic cleaning

There are a few options on the market for choosing an acoustic cleaning system. The most common of these are sonic cleaning and Infrasound cleaning. There are a few differences between these two alternatives in characteristics and effectiveness.

Sonic cleaning uses a form of high-frequency sound to preventively clean the boiler, while Infrasound cleaning uses low-frequency sound. In practice, this means that you can run the Infrasound cleaning system on higher sound levels compared to sonic cleaning before causing discomfort.

The wavelength is an important factor in choosing an acoustic cleaning system. An infrasound cleaning system produces a longer wavelength, which enables one single unit to clean an entire economizer, SCR, etc. Sonic cleaning instead uses a short wavelength and therefore has to operate more units.

The longer wavelength also enables:

• More acoustic diffraction – Acoustic diffraction refers to the spreading of sound waves in various directions. Increased acoustic diffraction means that sound waves can reach a wider area within the boiler, increasing the chances of dislodging deposits from different surfaces. This improves the overall cleaning efficiency.
• Less acoustic absorption – Acoustic absopriton occurs when sound waves are absorbed by materials, reducing their intensity and effectiveness in cleaning. To ensure that most of the acoustic energy is used for cleaning the desired area, it’s better to have less acoustic absorption in the boiler. Since a lower proportion of sound energy is being lost as heat, this leads to a more efficient use of energy.
• Makes the sound omnidirectional – To ensure thorough cleaning and prevent the formation of hot spots or uneven heating, it’s important to have an omnidirectional sound field. This means that the sound waves are emitted in all directions, ensuring that they can reach deposits in hard-to-reach areas.

 

If you are interested in learning more about the differences in acoustic cleaning methods.

Download our white paper here

 

Conclusion

In conclusion, constant availability and optimal performance of power boilers are vital factors for ensuring efficient energy production. Over time, fouling, scaling, and deposit buildup on heat transferring surfaces can hinder a boiler’s effectiveness, leading to plugging and reduced heat transfer. Traditionally, manual cleaning during designated stoppages has been the norm, but it comes at the cost of significant energy production losses.

Acoustic cleaning systems offers a more efficient and effective solution to maximize power boilers potential, all in the goal to achieve constant boiler availability.

 

If you are interested in taking your power boiler to new heights, contact us today!