In the early autumn of 2020, KPA Unicon carried out a major modernization project for Honkainfra Oy, the heating company of the municipality of Puolanka.

With the upgrading, the old boiler plant received an additional lifespan of at least 10 years, and the nominal load increased by the necessary 0.5 MW.

KPA Unicon carried out the modernization project as a complete delivery, excluding electrical and automation installations. Upgrades to the electrical and automation system were implemented by Honkainfra itself.

The delivery included the dismantling of the old equipment and the roof of the plant building, the replacement of the convection part of the boiler, the installation of new equipment and the commissioning. The new convection part was manufactured at KPA Unicon’s own workshop in Kiuruvesi and the ducts and service platforms at KPA Unicon’s Lapua workshop.

“The maintenance costs of the municipal heating plant had started to rise because it was 20 years old. We observed and followed the development of the situation. It was clear that it was necessary to start upgrading the plant,” says Markku Nivakoski, Chairman of the Board of Honkainfra Oy.

Modernization is a profitable option

In the case of Puolanka, the modernization of the existing plant made sense, as the plant had been renovated over the years, and some of the equipment was still in good condition. For example, a flue gas scrubber and associated ductwork have been retrofitted.

Due to the scrubber, the plant will meet the stricter emission limits in 2030, so there was no need to make changes to the emissions. However, the technical reliability of the plant required improvement.

“The Puolanka plant is an older plant from another Finnish plant supplier but is technically familiar to us. The plant had some components in refurbished condition, which we upgraded as part of the delivery. In addition, our delivery also included a soot blower to handle the sweeping that had previously been done manually. Thanks to the new soot blower, unnecessary shutdowns of the plant during the heating season will also be avoided,” says Esa Kukkonen from KPA Unicon.

The building itself was original – cramped and low – and required an upgrade, as the new convection part is slightly larger than the old one. At the same time, an increase of one meter in height resulted in more spacious maintenance spaces and service platforms.

“The old roof had to be dismantled anyway to get the old equipment lifted out and the new equipment in. At the same time, it made sense to raise the ceiling so that we could get more functional facilities,” Nivakoski explains.

Owing to the modernization, the plant’s capacity increased from 2.5 megawatts to three megawatts. Besides the renovation, the boiler was also equipped with circulation gas ducts, which enables the use of a drier fuel if necessary.

The dimensioning of the nominal load increase took into account the municipality’s goal of increasing business, employment and production related to wood raw material.

“Since there was not detailed information at the time about, let’s say, the future load needs for the next decade, this was a good time to do the renovation. Its repayment period is estimated to be 10 years. In that time, we’ll be able to see the results.”

Nivakoski knows that when upgrading an old plant, compromises will have to be made. For example, part of the old duct system was left in use even though it is almost at the end of its lifecycle.

“We can correct the small deficiencies in them in the coming summers. Overall, the usability and conditions of the plant have improved significantly,” he asserts.

Alongside the increase in capacity, the use of reserve boilers has decreased. Likewise, maintenance and operating costs have also been reduced since the sweeping costs are lower. Operating services Honkainfra procures from the Municipality of Puolanka.

“In practice, the boiler plant employs 0.5 man-years: one person is responsible for operation and maintenance, and the municipality’s property maintenance is responsible for operation after normal working hours.”