TLT-Turbo ensures reliability at a power plant in Laos
When a power plant customer of TLT-Turbo needed to retrofit its fresh air fans to ensure the plant's availability and reliability, TLT-Turbo was the perfect partner – supplying both the equipment and the solutions required for installation.
This customer experienced three incidents of damage to the power plant's forced draft fans within a year. Strong vibrations caused blade shafts, including the blades, to break off. Rebuilding the existing fans with more reliable rotors from TLT-Turbo significantly improved operating time and reliability.
Vibration problems with existing fans
The power plant, commissioned in 2015, is the largest in Laos, with a capacity of 1,878 MW. It consists of three lignite-fired boilers, each with a capacity of 626 MW. Initially, the power plant was equipped with forced draft fans (two per boiler) by a market competitor of TLT-Turbo. Since the plant began operating, the variable-pitch axial fans have repeatedly experienced significant vibration issues. Between June 2016 and June 2017, these issues resulted in three serious incidents involving broken blade shafts and blades. Despite the fans' short operating time, the customer decided to replace the defective rotors. Thanks to our many years of experience and technical expertise, we convinced the customer that TLT-Turbo, in cooperation with Zenith Power System Co., Ltd., TLT-Turbo's local partner in Thailand and Laos, was the right supplier for the job.
Efficient rebuild concept for quick fan replacement
The customer's top priority was replacing the damaged fans with reliable ones as quickly as possible. Additionally, minimizing the power plant's downtime was crucial, meaning the installation process had to be as short as possible. To meet these requirements, the engineering team at TLT-Turbo in Germany developed a special rebuild and installation concept in which only the rotor and main bearing needed to be replaced. This concept enabled the reuse of the housing, drive train, and oil system of the original fan, allowing TLT-Turbo to replace and commission the first two fans in less than four months after receiving the order. This approach also allowed a large part of the fan to be retained and reused.
Additionally, the joint installation team from TLT-Turbo and Zenith Power System Co., Ltd. replaced the two fans and returned them to operation within 48 hours of the power plant's shutdown. To meet the customer's expectations and requirements, the team planned the rebuild measures down to the smallest detail and prepared for all possible problems. For instance, a hose press with press fittings and hoses of various sizes was delivered to the construction site for this project only. This ensured that suitable new hydraulic hoses could be manufactured on site if the existing ones did not fit the new TLT-Turbo rotor.
Reduced vibrations and trouble-free operation
The vibration values of the forced draft fans rebuilt by TLT-Turbo are well below the standard limit. There have been no further malfunctions since the rebuild – the fans are operating properly and without disruption. The customer is very satisfied not only with the technical implementation but also with how quickly the rebuild was completed, which significantly reduced downtime. Following the successful conversion of the first two fans, TLT-Turbo was commissioned to convert the power plant's other four forced draft fans. These four fans were also converted within 48 hours each and have been running smoothly ever since.
