Rapid pump upgrade delivers improved efficiency

31 January, 2023

Power stations using steam turbines to drive generators are reliant on boiler feed pumps, among several other vital pieces of equipment, to ensure output to the grid matches demand from consumers. Periodic planned maintenance should ensure continued reliability, but as these pumps reach the end of their service lives, the frequency of interventions can increase and even affect the productivity of the plant. One facility in South Korea enlisted support from Sulzer to retrofit four boiler feed pumps after the original equipment manufacturer (OEM) couldn’t supply a cost-effective solution.

After 28 years in service, the original group of four ring-section boiler feed pumps were starting to show their age. Typically, the pumps would have been overhauled every three years as part of a planned maintenance routine However, more recently, the efficiency of the pumps had started to decrease, and vibration levels were rising noticeably.

Designing the best solution

For the maintenance team in the power plant, the increased frequency of interventions was becoming difficult to manage and this situation was compounded by the lack of support received from the local pump OEM. Having established the drop in performance and measured intense vibration at 8 mm/s, the decision was taken to appoint an alternate pump repair specialist.

The owners of the power plant already had considerable experience of Sulzer’s pumps that were installed across several of their other power generating facilities. The operational performance and reliability witnessed over many years convinced the site managers to request the company to provide a solution to their problems.

Sulzer assembled a team of specialist pump and mechanical engineers to conduct a comprehensive study of the existing installation and to assess the most suitable solution. Having analysed the condition of the original pumps, the team concluded they had reached the end of their service lives and replacements would be needed.

Best-in-class project management

In terms of time and expense, the best design would be a drop-in replacement that required minimal alterations to the surrounding infrastructure. This proposal would allow Sulzer to design, manufacture and test the new pumps off-site in preparation for a planned outage, during which the pump changeover could be completed. By creating a pump with the same external connections, the time to carry out the switchover would be kept to a minimum.

Using the measurements taken during the initial investigation, the Sulzer team engineered a fully customized pump with the hydraulic design based on its MD series. The aim was to deliver the same performance with improved efficiency, which was achieved through the optimized design.

In addition to the plug-and-play boiler feed pump, Sulzer also supplied automatic recirculation (ARC) valves, drive couplings, seals, and some additional lube oil pipework. The turn-key project saw Sulzer deliver all the design and manufacturing aspects as well as supplying the ancillaries and civils works, ensuring peace of mind for the customer and enabling the plant engineers to focus on their core operations.