“Sarlin Balance is a great tool for achieving great performance”

The energy company for the Finnish capital, Helsingin Energia, produces electricity and district heating mainly in its own power plants. The fuel for the Hanasaari and Salmisaari plants is coal, the benefits of which include good availability, reasonable and stable price, and easy storage even in case of emergency. The environmental impact of the power plants is reduced by efficient sulphur removal and ash separation.

The Hanasaari coal plant uses compressed air for dust conveying in the sulphur removal plant, for tube filter cleaning, as well as for working and instrument air and pneumatic mechanisms.

The plant featured four separate networks with a total of 8 compressors, 4 or 5 of which were mostly on/off -regulated. To survey the production and usage of compressed air in Hanasaari, the system was “health-checked” by Sarlin Air Audit to find the actual air usage and the actual utilisation rate of the compressors.

An upgrade project combined all four networks under one compressor, and a fully oil-free high-speed turbo compressor was selected.

The system is controlled by Sarlin Balance. The entire operational staff attended the Balance training and the training groups totalled six. The Sarlin Balance control works continuously in the power plant control room, reporting the data and relaying any alarms to Sarlin. Sarlin Balance optimises the compressed-air system and maintains the pressure at exactly the correct level.

The semi-annual Balance report gives a graphical image of the changes and trends, as well as other significant features in the system.

“In the autumn, when the Sarlin Balance control was operating but the new compressor had not yet been launched, we measured the power consumption as 8 to 8.5 kW per cubic metre per minute of compressed air”, the maintenance engineer says. “Now that the new compressor is operational, the corresponding figure is 6 to 6.5 kW. The network pressure level is now 7.2 bar. We intend to drop the network pressure as low as possible in order to find the minimum operational level. Our guess is that we can drop it down to 6.5 bar.”

“Sarlin Balance is a great tool for achieving great performance.”

“A reduction of 0.1 bar in the pressure level is enough to yield large annual energy savings. All the energy we use at the power plant is energy we cannot sell.”

“Many people think we do not need to save energy at the power plant because we produce the electricity ourselves.”

“There is one more tailored Sarlin Balance feature we wish to have: The control system should drive the stand-by units once a week to ensure that they do not stand unused over the winter. We require 100% spare capacity, so every compressor must be available at all times.”

The entire power plant is due for an energy survey and process optimisation. The compressed-air project is one of the completed areas of development. The reduction in pressure levels is obvious – the energy savings by Sarlin Balance are significant indeed.