Situation
Darlington Nuclear Generating Station with 16 Sulzer single-stage vertical reheater drain pumps
Challenge
Large temperature differences and high pressure led to inadequate cooling
Solution
SHFV1/42-E1, a new sealing system with API plan 23
Darlington Nuclear Generating Station is located 70 km east of Toronto (Canada). The four unit station is the newest generating station of Ontario Power, performs a total output of 3,512 MW and provides about 20 % of Ontario‘s electricity needs - enough to serve a city of two million people.
16 Sulzer single-stage vertical reheater drain pumps type BJ3X4X11 model TXR are installed. The second stage reheater drains system drains the condensate, and vents any uncondensed steam from the second stage reheater tube bundles and directs these to the steam generator and the HP heater.
The pumps in question were originally equipped with a competitor‘s seal system, operated acc. to API plan 41. High temperature and high pressure caused problems for the seal and its supply system. Because of large temperature differences between the cold cooling medium (lake water) and the hot process medium (demineralized water) an excessive deposit of cooling water sediment occured and the coil of the heat exchanger regularly plugged. Therefore, inadequate cooling was provided which resulted in dry running of the seal faces and ended in seal failure.
These failures occurred up to 10 times a year and caused a loss of efficiency of 4 MW, costing 5,000 CAD per day.
Illustr. 1: SHFV High pressure mechanical seal for boiler circulation pumps. Dual seal in tandem arrangement, with pumping screw
Illustr. 2: Yellow parts = rotating, blue = stationary, gray = housing
EagleBurgmann designed a new sealing system, the SHFV1/42-E1 with API plan 23. This system had to pass through a performance test at the EagleBurgmann facilities in Wolfratshausen, Germany. The test was arranged with the original equipment and under operation conditions of Darlington Nuclear. All tests have been performed successfully without any problems.
Seal features
- Stationary multiple springs and integrated pumping screw
- Pressure stabilized reinforced carbon seal face with hardened metal support ring
- Material combination for optimal heat transfer at seal faces
- Robust design prevents seal face distortion at high pressure insuring a stable lubricating film
- Safe and low leakage behavior in high speed and pressure applications
The first SHFV1/42-E1 with API plan 23 was installed in 2007. Another 15 sealing systems follwed in 2008. Since start-up the seals show excellent performance and run without any problems.
- Medium: demineralized water
- Operating temperature: 288 °C (550 °F)
- Gland injection temperature: 20 °C (68 °F)
- Stuffing box pressure: 50 bar (725 PSIG)
- Rotational speed: 3,600 min-1
- Pump type: Sulzer BJ3X4X11 model TXR
- Operation: 100 % duty pumps, 24/7 operation
Further reference projects
United Kingdom
10 years of reliability: Protecting the heart of Great Britain’s natural gas infrastructure from failure
In Great Britain, a shortage in natural gas supply has severe consequences: Since the country switched from coal-fired to gas-fired power stations, a gas supply shortage makes households and industrial consumers not only vulnerable to failing heating and gas stoves, but also to power outages. Companies along the value and transportation chain of natural gas are therefore especially dependent on reliable equipment.
Finland
Does not blow off steam
A boiler circulation pump in a power plant conveys very hot and pressurized water. The pump has no cooling jacket, which increases the risk of a thermosiphon effect.
Germany
Flexible and hygienic expansion joints for dairy products
By means of custom-made PLUG & RUN expansion joints with a more wear-resistant material, EagleBurgmann was able to provide a solution which ideally fulfills the requirements with regard to wear while at the same time significantly reducing the changeover time.
Germany
New sealing concept for roller dryers
Mechanical seals are not always the best choice. In roller dryers used in the production of pharmaceutical powder, abrupt shaft deflections during processing led to increased seal wear. Operation was maintenance-intensive and prone to faults.
Poland
Reliable storage of crude oil
Special expansion joints from EagleBurgmann compensate for these position changes and work reliably even under unfavorable conditions such as low temperatures, proximity to the sea and explosive environments.
Germany
RoTechBooster for Compressors in Natural Gas Storage
The Etzel oil and gas cavern system is situated southwest of Wilhelmshaven, not far from the North Sea coast. A vast salt dome houses the more than 70 caverns which store crude oil and natural gas at depths between 900 and 1,700 meters. Etzel is integrated in the northwest European oil and gas pipeline network and makes a significant contribution to the safe and reliable supply of gas to Germany and all of Europe.
