Progressing Cavity Pumps in Power Plants

Background

Progressing cavity pumps can be used universally due to their mode of operation and design. One field of application is the pumping of abrasive media, which can contain both solids and fibers. Examples include sludge in sewage treatment plants. These pumps are also well suited for dosing. Even with changing operating pressures and medium consistencies, they generate a continuous and pulsation-free flow. Another characteristic of a progressive cavity pump is the low turbulence and mixing of the pumped medium due to gentle pumping. This is why progressive cavity pumps in stainless steel design are also used in the food, beverage and cosmetics industries. But it is not only in these industries that gentle pumping is important; there are also applications in power plants where this property is absolutely essential.

The power station is Germany's most beautiful Art Nouveau power station and has been preserved in its original state.

Challenge

Progressing cavity pumps at the Heimbach power plant

The Heimbach hydroelectric power plant in the North Eifel region is one of the oldest still-operating hydroelectric plants in Germany. Originally constructed in 1905, it was completely renovated in 1974/1975 and converted to modern technology. The eight original turbine groups with 12,000 kW of output were replaced by two new machines that generate 16,000 kW. In 2011, the machines and technical systems were renovated and modernized.

Elevated requirements for environmental protection led to another round of modernization in 2012. Until then, centrifugal pumps moved cooling and sealing water in the discharge channels through an oil trap and into a reservoir and then into the Rur river. Centrifugal pumps are generally well suited for pumping clean water. However, oil and water tended to emulsify during this special pumping task. During regular operations, this was not a problem. There was plenty of time for the oil/water mixture to collect in front of the oil trap, causing the emulsified oil to re-float. However, in the event of damage, if large quantities of oil escaped from the coolers, the oil traps would be unable to clean the emulsion quickly enough and well enough. Due to these safety considerations, environmental regulations now require the use of low-pulsation and low-turbulence progressing cavity pumps in this process.

Solution

Allweiler progressing cavity pumps

RWE Power AG, the operator of the power plant, opted for progressing cavity pumps of the Allweiler^® brand. The Allweiler plant in Bottrop has specialized in the production of progressing cavity pumps in various sizes for a wide range of applications and pumping conditions for more than 50 years. It is also one of the few manufacturers to produce all rotors and stators itself. Over 20 materials allow maximum service life thanks to optimum adaptation to the respective medium. The new ALLDUR^® elastomer compound increases the service life of stators up to five times that of conventional compounds.

Allweiler progressing cavity pump

Former switchboard Heimbach power station.

Reliable and ready for the future

At the Heimbach and Schwammenauel power plants, two pumps of different sizes from the “AEB1F” series replaced the previous centrifugal pumps. The pumps are frequency-controlled and deliver between 500 and 700 l/min at around 200 1/min. Depending on the volume of cooling and rinsing water, they operate approximately every 15 minutes. Since installation, there have been no faults and no need for maintenance. “The pumps have met all our expectations,” says Frank Winkens, who is responsible for pump technology at the power plant. The manufacturer expects the pumps to continue working for another 20 to 30 years without the need for external intervention.

Alte Maschineneinsätze Kraftwerk Heimbach

One of the old machine sets that were in operation from 1905 to 1974.

With frequency control, the pump units can be controlled with precision, but their benefits do not end there. Considering the possibility that the power plant may have to pay for its own power consumption in the future, the pump units are also a secure investment.

Delivery, installation, and commissioning from one source

Before the decision was made, offers from several manufacturers were compared. The decisive factor for Allweiler^® was ultimately the combination of high quality and reasonable price. “We also use pumps from this manufacturer in many other power plants and have only had good experiences,” says F. Winkens.

Progressing Cavity Pumps

Allweiler

Specifically developed for our progressing cavity pumps with a clear focus on cost effectiveness. The compound formulation is the key to how long a stator will maintain its original flow rate.

More details

Progressing Cavity Pumps

Allweiler

Optimizes all hydraulic characteristics such as flow pattern, power absorption and distribution, and lubrication to ensure long service life and maximum efficiency.

Max. Capacity [l/min] :

3.800

Max. Discharge Pressure [bar] :

Max. Fluid Temperature [°C] :

135

Max. Viscosity [mm²/s] :

300.000

More details