"We have been using the filter for years. You can't even notice its operation, but I've seen firsthand how it keeps our district heating network clean," sums up Antti Köngäs, operation and maintenance manager at Loviisan Voima.
Porvoon Energia acquired a Sofi Filter® SF200 for the Loviisa power plant in 2016. The filter was introduced as a side stream filter with the aim of removing fine solids accumulated in the district heating network. Often that solid matter is corrosion products, i.e. rust, and various precipitates due to, for example, the hardness of the water. The concentration of solids in the network can increase when people open the valves of their circulating water radiators. Finnish Energy advises for the solid content of network circulating water to be less than 0.5 mg/kg. "According to our experience, the solid content in most networks exceeds this threshold value and cleaning of the network would be necessary," says Anssi Laiho, field service engineer of Sofi Filtration Oy.
Measuring the concentration of solids in the network water is not necessarily very common in plants, and the accumulation of solids in the network may go unnoticed. Plant maintenance are busy and time is limited. However, in terms of the efficient and reliable operation of the network, it is essential that the circulating water remains clean.
"We offer network cleaning to our customers as a service, so customers do not have to invest in the equipment themselves. We measure the solid content of the water in the network and are able to tell the customer where the water in their network ranks in terms of cleanliness in relation to others networks, and if cleaning is therefore necessary," says Toni Nikku, sales representative of Sofi Filtration Oy.