Metso and Stora Enso Corp. have inked an agreement for a single-drum conversion of Stora Enso’s Imatra Mills’ recovery boiler, to be completed in the fall of 2012.

The upper and lower drum of the recovery boiler and the steam generating bank between them will be replaced by a new drum and separate boiler bank elements needed for heat recovery. At the same time, the second stage of the economizer will be rebuilt.

“The conversion will significantly extend the boiler’s lifetime and allow for a possible capacity increase in the future. In addition, the conversion will improve the boiler’s availability, secure safe operation and reduce maintenance costs. Further advantages offered by a single-drum conversion compared to replacing the existing design are a shorter downtime and the reliability of the solution,” says Jouni Koskinen, sales manager, boiler conversions, from Metso.

The recovery boiler was built in 1987 and its current capacity is about 1,700 metric tons of dry solids per day.