Does not blow off steam

Mechanical seal SHFVI for a boiler circulation pump

KeyVisual_CaseStudy_SHFVI_Finland
Situation

Temperature layering can damage the pump shaft and seal

Challenge

Prevent exchange of cold and warm water on the shaft without cooling jacket

Solution

Mechanical seal SHFVI and screw pump HPS from EagleBurgmann

CaseStudy_SHFVI_Finland

Waste, natural gas, coal, wood and biogas are the fuels used by a Finnish power supplier to produce electricity and district heating in two power plants. The seals of a boiler circulation pump in the coal-fired block must function properly up to 300 °C and at a pressure of up to 150 bar.

This pump delivers very hot boiler water to a steam boiler, and the seal prevents the hot and pressurized boiler water from escaping as steam at the pump shaft. The seal therefore plays an immense role in the safety of power plant personnel. Likewise, the availability of the power plant and the reliable generation of electricity and district heating also depends on functioning pumps and seals.

CaseStudy_SHFVI_Finland_pump_customer

A market player had initially equipped the pump with mechanical seals. But they failed unexpectedly regularly within three to six months after commissioning. This resulted in several dangerous steam leaks. Luckily the plant personnel were not injured, but the seal failures incurred immense costs. The power plant operator then commissioned a different pump manufacturer to offer a new pump. But it was determined that the use of a new pump was not feasible for design reasons. And so this renowned manufacturer approached EagleBurgmann with the aim of collaborating closely to develop a permanently safe sealing solution.

The project began with an investigation into the root cause of the seal failure. The original seal supply included a cooling circuit in accordance with API Plan 23. This cooling circuit was equipped with a large heat exchanger. However, the pump had no cooling jacket - a fact that EagleBurgmann also had to take into account.

The mechanical seal SHFVI from EagleBurgmann is the ideal product for applications under extreme conditions - at high pressures up to 150 bar (2,175 PSI) and temperatures up to 350 °C (662 °F). It was optimized to withstand the deformation caused by frequent starts and stops. For quick and easy installation, it is supplied as a pre-assembled unit. The specifically designed connection parts have been adapted to the pump installation space.

A seal face developed for boiler feed and boiler circulation pumps and designed for high pressures was selected for use in this boiler feed pump. The design of the rotating seat and the integrated pumping screw ensure optimum heat dissipation from the seal.

Operating conditions:

  • Shaft diameter: d = 76 mm (2.99")
  • Pressure: p1 = 146 bar (2,118 PSI)
  • Temperature: t = 300 °C (572 °F)
  • Sliding velocity: vg = 15 m/s (49 ft/s)
  • Medium: Boiler water

CaseStudy_SHFVI_Finland_pump

During standstill at high temperatures, typically a thermosiphon effect occurs. Due to this effect, warm water is at the top of the pump shaft and relatively cold water at the bottom. This can lead to temperature layering and cause distortion of seal parts, the pump shaft and the pump housing. EagleBurgmann therefore installed a Thermo Stop to prevent such damage.

A segmented carbon ring with lift-off grooves prevents the exchange of cold and warm water and thus temperature layering. No leakage occurs during standstill periods, which prevents the carbon seal rings from eroding.

HPS_003.png

The SHFVI seal also requires a cooling circuit via an external cooler in accordance with API Plan 23. This allowed the existing cooling circuit to be used. However, neither the seal nor the pump housing had enough space for the required cooling jacket. EagleBurgmann then decided to use an external screw pump of the HPS series to replace the necessary jacket cooling by forced circulation in Plan 23 for standstill. This screw pump is hermetically sealed and largely maintenance-free.

After two years of trouble-free use, the operator of the power plant and the pump manufacturer were so satisfied with the EagleBurgmann solution that another pump was retrofitted. The SHFVI seal has also been successfully used in boiler feed and boiler circulation pumps of other power plant operators.

Do you have similar requirements? Please contact us.

Solution: SHFVI boiler circulation pump Finland

Further reference projects

KeyVisual_RoTechBooster_Dock_Sud
Argentina

Clean gas despite fluctuating operating conditions

Frequent starts and stops are a severe test for gas-lubricated compressor seals. Installed in an Argentinean combined cycle power plant is an EagleBurgmann supply system that provides a continuous gas flow rate for the seals and adapts it to changing conditions. Since then, the operational reliability of the compressors has increased significantly.

Read on for the entire case study
KeyVisual_CaseStudy_SHVI-CGSH_USA.jpg
United States

Convincing high pressure seals for pipeline pumps

Reduce maintenance costs for seal supply systems and extend MTBR intervals - EagleBurgmann's task was to significantly improve the availability of unmanned pump stations in a gas pipeline in Texas with single seals for multifluid pumps.

Read on for the entire case study
KeyVisual_CaseStudy_Schiffstechnik.jpg
Germany

Cruise liners with DiamondFace-coated mechanical seals

Cruise liners have to reduce their sulfur emissions in Emission-Controlled Areas (ECAs). To accomplish this, light fuel oil is used in coastal regions - with significant consequences for the ship's fuel supply.

Read the complete case study
KeyVisual_CaseStudy_DF-M7N.jpg
Germany

DF-M7N DiamondFace for tank drainage pumps

The chemical company Global Amines is one of the worldwide leading manufacturers of special chemicals. The "Southeast Bavarian Chemical Triangle", near Altötting, Germany is the location of the Gendorf plant. Global Amines produces preliminary, intermediate and finished chemical products here. EagleBurgmann successfully converted a chemical standard pump from a competitor's seal to an EagleBurgmann DF-M7N DiamondFace mechanical seal and achieved significantly increased pump and system availability.

Read the complete case study
KeyVisual_CaseStudy_MFLWTI.jpg
Germany

DF-MFLWTI DiamondFace mechanical seal for refinery pumps

The TOTAL refinery at the Leuna chemicals site is one of the most state-of-the art facilities of its type in Europe. It processes around 30,000 tonnes of crude oil every day, most of which is pumped in from Russia.

Read the complete case study
KeyVisual CaseStudy Osvat shutterstock_190565291.jpg
Brazil

DiamondFace coated mechanical seals in crude oil application

The 275 km OSVAT pipeline network carries about 55 % of the crude oil explored in Brazil. In 12 Sulzer heavy duty pumps, which maintain the fast flow of crude oil from the wells to the final destination, several wear-free mechanical seals with DiamondFace technology operate without failure and provide economic advantages for the owner.

Read the complete case study
Show all references
Newsletter

Excellence in Practice

With our free e-mail newsletter „Excellence in Practice“, you will receive first-hand information about current products, services, references and worthwhile industry insights.