Blast effects
Detonation cleaning is successful in continuous-maintenance mode and remedial cleaning mode where established deposits must be removed. Acoustic cleaning is used primarily in a continuous-maintenance mode and is inadequate for removing ash that’s been allowed to accumulate and sinter. A series of before and after photos posted on the ShockSystem web site (www.shock-system.com) illustrate the cleaning effectiveness of the system.
Results of demonstrations as well as permanent installations of the ShockSystem have shown on-line detonation cleaning in various boiler regions to be as effective as or more effective than conventional methods in controlling ash deposit accumulation, limiting plant outages, and improving heat rate (Figure 5).
5. It’s a blast. The omnidirectional nature of the blast releases energy in three dimensions, thereby giving the heat transfer surface a thorough cleaning. The process has three stages (left to right): First is bridging and platenization—shown in a cross section of a boiler before cleaning, then a shockwave moves through the boiler tube space when the ShockSystem is ignited, and, finally, partial cleaning of the tube surfaces is illustrated after the shockwave dissipates. Cleaning can be repeated as needed. Courtesy: Pratt & Whitney MMI
The non-line-of-sight cleaning ability of the blast wave cannot be achieved by conventional sootblower jets. The detonation cleaning device operates during normal boiler operations, thereby reducing the number and/or duration of plant outages required for cleaning otherwise inaccessible locations. This new technique is expected to result in less tube wear attributable to particle impact erosion, thanks to the lower entrained ash velocity associated with the blast wave. This translates into longer unit life and a reduced number of unplanned outages.
The on-line detonation cleaning combustor does not burden valuable plant resources such as steam or high-pressure air (and the associated compressors). This advantage is expected to result in a significantly lower cost of operation. Another advantage relative to conventional sootblower technology is that the on-line detonation cleaning device has fewer mechanical parts, because it does not need to enter the boiler or be retracted. That means reduced maintenance cost. Moreover, the detonation combustor can be configured in a variety of ways, enabling installations in more confined areas than conventional retractable sootblowers, which commonly require a long, open-space external to boiler for installation.
—Kirk Lupkes (kirk.lupkes@pw.utc.com) is the engineering manager of Pratt & Whitney MMI. A. Tofa McCormick (andrew.mccormick@pw.utc.com) is a senior analyst in the Marketing & Communications group.
Email
Comments
Print
Reuse
