How do I reduce power consumption by a factor of 2.5?

How can energy consumption be reduced by a factor of 2.5? By replacing old hose pumps with sliding shoes with modern hose pumps equipped with rollers.

At Nordjyllandsværket – Vattenfall A/S in Vodskov, Denmark – three older hose pumps were replaced by three new LSM hose pumps in the summer of 2015.

At the coal-fired power plant, flue gas is cleaned of sulphur using lime. The hose pumps are used to pump lime slurry into the flue gas cleaning system.

With a total capacity of 3,334 MW electrical output and 450 MJ/s thermal output, one might think that energy consumption would not be a major concern. However, Nordjyllandsværket has long been among the world's most energy-efficient power plants, with up to 91% of the energy contained in the coal being utilised. This makes it important to ensure that as much energy as possible is sold rather than consumed internally at the plant.

“We purchased our first LSM hose pump in 2012, and we have had very good experience with it. Among other things, we can document a 50% reduction in repair costs over 17,000 operating hours,” says engineer Svend Mølbach from Nordjyllandsværket.

The lime slurry has a density of 1,200–1,350 kg/m³ and a pH value above 10. It is used to maintain a constant pH value of approximately 5.35 in the plant's 1,100 m³ absorber.

When the new LSM 50 pumps were installed, the question was whether they could provide the required capacity with motors rated at only one quarter of the power of the previous pumps.

“We were curious to see whether the new LSM 50 pumps, with only one quarter of the motor size we previously used, would be sufficient. But they easily achieve the specified 6 m³ per hour per pump. The pumps run quietly and efficiently, and we have significantly reduced our energy consumption per cubic metre pumped,” says Svend Mølbach.

He also highlights the simple hose replacement as an additional benefit, helping to improve working conditions for the plant's employees.

At LSM Pumper, significant energy savings are often seen when older hose pumps with sliding shoes are replaced by modern hose pumps with rollers.

“Hose pumps with sliding shoes are simply energy-intensive. At the same time, LSM hose pumps have the largest pumping volume on the market, which means they can run more slowly and smoothly. This results in both lower energy consumption and a longer pump service life,” says Leo Sørensen, Managing Director of LSM Pumper.

Project facts

• Customer: Nordjyllandsværket – Vattenfall A/S, Vodskov, Denmark

• Application: Pumping lime slurry for flue gas cleaning

• Pumps: 3 × LSM 50

• Medium: Lime slurry, density 1,200–1,350 kg/m³

• pH value: >10

• Capacity: 6 m³/h per pump

• Previous solution: Hose pumps with sliding shoes

• New solution: LSM hose pumps with rollers

• Result: Significantly reduced energy consumption, lower repair costs and easier maintenance