A sintering plant at a major steel works in Eastern Japan had a horizontal design Ljungström gas-gas heater (GGH) that had been operating for more than 40 years. The GGH had a rotor diameter of more than 10 meters, and during the past 3-4 years had been facing mechanical problems resulting from the long term operation, and equipment that had exceeded its design life. There was an urgent need to replace the aged unit with new equipment, but the customer faced the difficult decision of avoiding a long plant shutdown and outage to replace the unit. Restrictions from the plant operational needs and local governmental pollution regulations, meant that a shutdown window of only 2 months was available to complete the replacement, which was far less than the typical 8 month construction period to dismantle an erect a new gas-gas heater.

After analyzing the schedule and space restrictions at the site, LJUNGSTRÖM developed a new construction method to shorten the overall construction period to 60 days. The tight project schedule also accommodated restrictions imposed by the COVID pandemic, such as delays on sea transportation and customs clearance. LJUNGSTRÖM completed the site pre-assembly of a new rotor unit at a limited space beside the existing GGH ahead of the construction period while complying with laws and meeting the customer needs. During the shutdown outage, the old GGH unit was disassembled within the first week, allowing 7 weeks for the construction of the new gas-gas heater. Lifting the pre-assembled rotor parts and unit with a large crane, LJUNGSTRÖM smoothly completed the construction work within the scheduled time frame.

“This project is a great success, and demonstrates the capabilities and flexibility of LJUNGSTRÖM to support our customers in challenging projects. We accomplished this replacement GGH within the aggressive construction schedule due to the expertise, commitment and focus of our LJUNGSTRÖM employees.” said Tomoharu Miyamoto, Managing Director, LJUNGSTRÖM Japan.