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Project Delivery: Feedwater Tank and Steam System Upgrade Project

By 20.2.2024February 23rd, 2024News
Sähkökattila valmiina kuljetettavaksi.

West Welding carried out a substantial feedwater and steam system modification and installation project in August-September 2023. The extensive modification and installation project was commissioned for a paper mill.

Large-scale modification and installation projects are challenging in terms of scheduling. A key factor in the project was West Welding Oy’s precise planning, which enabled the rapid delivery of the feedwater tank. Thus, the new electric boiler could be brought into operation on an accelerated schedule. In such projects, thorough pre-preparations and careful planning are of primary importance. They help overcome scheduling challenges. A knowledgeable and well-coordinated installation team is also important so that the work progresses smoothly and on schedule.

Long Preparations Facilitated Installation

Pre-manufacturing of the device and necessary parts took place during spring 2023. The installation phase began in August with installation and lifting work, where the feedwater tank, along with its base, was installed into the boiler building. Thanks to careful pre-preparations, the feedwater tank was installed very quickly. Since everything was ready in three days, the actual installation of the electric boiler could start on time.

In the second phase, at the beginning of September, more extensive installation work began during a factory shutdown, lasting seven days. The project at the factory proceeded around the clock, and the power plant was out of operation during this time. Initially, old pipelines, valves, and supports were removed, and old valves were serviced. After this, high-pressure steam was built in a new form. Among other things, the steam log and a significant part of the pipeline were renewed and valves were added. The removed and now serviced valves and pipeline supports were installed in place.

West Welding’s technical expert Tomi Ketola tells that the steam log was delivered to the site ready-made and pipes were pre-fabricated. Accurate preparations during the installation phase speeded up the work considerably.

Challenges from Limited Space in an Old Building

Even though pre-preparations facilitated the installation, many of the installations and weldings performed on-site were quite demanding. The small and limited spaces had to be carefully considered both in planning and during installation. Just transporting the necessary items to their places was a big job. When large components and piping preforms are designed to be moved in tight spaces, quite a lot of welding remains to be done on the site.

“We also welded everything on-site using the TIG method to achieve the best possible outcome, even though it took a bit more time,” Tomi Ketola explains.

Ketola adds that the challenges in installations were caused by the really tight and limited spaces. This was especially true for steam valves, which were massive in this project. The steam pipes implemented according to the PED directive required strong professionalism. The installation plan challenges the wall thickness of steam pipes, making them heavy. Heavy structures also require large valves. The largest single valve weighed nearly three tons, more than the steam log itself. During the design phase, routes were identified for removing old pipelines, valves, and structures, and for constructing new ones.

“We had to construct various lifting rails and tracks ourselves to make it work,” says Ketola.

Race Against Time

With a very tight schedule, work on the site continued night and day. In total, 17 workers were on-site, some on the day shift and some on the night shift. In the final phase, weekends were also utilized with the help of additional employees.

Tomi Ketola mentions that all shift changes went smoothly and despite the tight schedule, work progressed at a steady pace. Any minor delays were quickly resolved through effective collaboration, and no major stoppages occurred. According to Ketola, the installation team was a key factor in completing the work just before the deadline.

“We had an absolutely great team overall, everything worked as planned. Even though the pressure was high, when we encountered tougher situations, we were able to take them with humor. Things never got too tense.”

Eventually, the work was completed three hours before the contract deadline.

“The deadline was at midnight, and the inspection was finished after 9 pm,” Ketola explains.

He further clarifies that there was a consensus on the site that they would stay on schedule.

“We were clear that, despite the tight schedule, we would make it. But it was also exciting, and it felt great to finish the work just before the deadline.”

Ketola also highligts how well everything was managed on the client’s side.

“Everything was very well managed by the client, which greatly affected our ability to meet the time requirements. For example, there were no other contractors on-site at the same time, so we didn’t have to worry about interfering with others’ work. We could just focus on our own work.”

The Electric Boiler Improved the Plant’s Maintenance Reliability and Ability to React to Price Fluctuations in the Electricity Market

The electric boiler provides significant savings in steam production in the current market situation, as the plant previously used natural gas. With the new electric boiler, there was also a need to update the steam log, which was completely replaced while the paper mill was out of use. The steam log was made from 16Mo3 heat-resistant carbon steel suitable for the conditions.

Tomi Ketola emphasizes the importance of the electric boiler from the point of view of maintenance reliability: “The new boiler was wanted just in case, to be able to produce process steam with the electric boiler even if gas was not available.”

Project director Panu Perasto added that the electric boiler could potentially bring savings to steam production through the utilization of energy market fluctuations: “Electricity is sometimes very cheap, occasionally even negatively priced. When electricity prices rise again, we can switch back to using other forms of energy.””

Quality is Worth Investing In

The greatest challenges in the installation at the papermill were posed by the tight schedule. Additionally, the tight spaces set their own limitations. Large components, such as pipelines, had to be moved and installed in tight spaces on a rapid schedule. We wouldn’t compromise on the quality, and the TIG welding method was chosen, even though it took a bit more time. However, investing in quality is worthwhile because it extends the lifespan, safety, and reliability of the installed devices and parts. In the quality inspection, all seams were thoroughly inspected by Kiwa Inspecta and met the required standards.

The project’s rapid and smooth success was primarily influenced by the extensive and carefully executed planning and pre-preparation stages, as well as efficiently carried out installation. Thanks to these, the project was completed smoothly on schedule. The world changes, and an electric boiler as part of a papermill’s steam production is modern again.