Sonic cleaning equipment from Kockum Sonics can simplify boiler maintenance, improve heat transfer efficiency, and deliver significant savings on FPSOs, shuttle tankers and other offshore vessels.
According to the company’s account manager Andreas Madsen, the technique is applied to prevent soot build-up in exhaust gas economizers in which heat is tapped from the exhaust gases.
Kockum Sonic’s Insonex infrasound emitter mounted in an economizer.
As the gases pass over the tubes into which the heat is transferred, the particles in them tend to adhere both to each other and to the surrounding surfaces, causing soot build-up. This has an adverse effect on heat transfer efficiency, and in the worst case, it may be necessary to use an auxiliary boiler to make up for the shortfall in required heat levels.
Traditionally soot build-up is tackled by means of a steam soot blower installed inside the economizer, but sonic cleaning can be much more effective. A sound emitter is used to generate a burst of sound waves with an energy level exceeding that of the adhesive forces acting on the particles. This leads to the particles ‘tearing’ loose from one another and from the surface of the tubes. A typical frequency would be sound wave emission for 10 seconds at 10-minute intervals, Madsen says.
Another benefit is that, unlike soot blowers, sonic cleaning is a dry method, which means that the tube lifetime is prolonged.
The company, which has been working with this technology since the 1970s, has had a lot of positive feedback. One marine customer reported a 7% increase in heat transfer and a resultant fuel saving of $4,000 a month. The investment paid for itself in less than five months, and the customer has gone on to install the system throughout its fleet.
Another customer reported that, in addition to fuel savings, the interval between boiler shutdowns for manual cleaning had been increased by nearly 100%.
Kockum Sonics can supply systems generating both audible sound and infrasound - inaudible sound. The latter is recommended when there are personnel working in the vicinity of the sonic cleaning operation.
For more information contact Andreas Madsen, Kockum Sonics. Tel +46 40 671 8818, fax +46 4021 6513,[email protected], www.kockumsonics.com
