Mechanical Draft
Component Replacements
BACKGROUND
A typical field erected mechanical draft cooling tower (9 cells) supporting one unit of a large combined cycle power station, 1980 MW(e), located in the central United States was in need of major repairs to ensure continued plant output and operational reliability. ATS was awarded a contract to replace the existing fouled heat transfer media (fill) and supports as well performing miscellaneous structural repairs and component replacement including wind walls and spray nozzles.
PROJECT CHALLENGES
As is typical in heavy industry, the schedule for this project represented the major challenge to be overcome for successful completion. With a contract award on Feb 1, 2020, ATS mobilized on Feb 10, 2020 to complete the replacement of 117,000 cubic feet of heat transfer media, replacement of 30% of the cooling tower structure located within the rain zone of the cooling tower as well as the other miscellaneous repairs. As much of the work as possible was to be completed within a 4 week outage with the remainder completed one cell at a time but no later than May 1, 2020 when warmer weather would require full capacity from the cooling tower. Certainly, a large scope of work to be completed in such a short time frame.
COMPONENT DESIGN
The original heat transfer media installed in the tower was a type known as “cross corrugated high efficiency media” that, unfortunately, is also a rather effective filter media when exposed to even moderate levels of suspended solids. The fouling in the existing media caused the tower to have reduced thermal capability and also represented a structural risk for the cooling tower. This is a common problem when actual suspended solids levels in the circulating water are higher than expected at the design stage of the original tower. To remedy the resulting thermal shortfall and structural risk due to fouling of the existing media, ATS proposed and installed a highly efficient, low fouling media that performs as well thermally as the originally media. The low fouling characteristics of this media will ensure thermal reliability over an extended period as compared to the original media and will reduce the structural risk inherent with the weight gain of fouled fill media.
RESULTS
• On Time completion, one month ahead of schedule
• Zero Incidents (Safety and Environmental)
• Expected thermal performance.