By the end of November 2016 the time had come: the “blast furnace 6 relining” project in Linz was officially completed. Thanks to the perfect teamwork it was even possible to finish ahead of the scheduled relining period of 136 days. The new blast furnace 6 is now once again fully operational and secures the future of the site in Linz.
Years of preparation
The term “relining” actually describes the replacement of the refractory brickwork on a blast furnace. This needs to be undertaken every few years to guarantee the productive efficiency of a blast furnace and ensure it remains state-of-the-art. The first of the two smaller blast furnaces in Linz, blast furnace 5, was relined in 2015. This year was the turn of the second, blast furnace 6. The 8-m-high blast furnace was last relined with new refractory bricks in 2009. However, preparations for relining the blast furnace again this year started back in 2011, and the work itself began in July 2016.
Milestones in implementation
The long project duration indicates the scale of this major project; the pre-project stage alone ran for two years (2011 to 2013). These first two years were chiefly concerned with the majority of the planning, e.g. determining what actually needed repairing, and the servicing this involves. The next stage was implementation:
- 2013: Refurbishing the gas purifiers
- 2014: Refurbishing the roof of the pouring bay including cranes
- 2015: Relining blast furnace 5, replacing the gas piping and parts of the cold blast piping, construction of the hot air blaster 6, and modernization of the entire infrastructure
- 2016: Relining of blast furnace 6
In mid-July 2016 they started cooling the furnace using water. Around 36,000 bathtubs (5,000 m³) of water were needed for cooling. This was followed by the demolition of the refractory brickwork, the relining of the furnace and the Cowper stove, the exchange of the casing, the reinstallation of all the piping and the conversion of the burdening conveyor. This was designed to be ready to handle the HBI (“sponge iron”) which is being produced at the new direct reduction plant in Texas.
Coordination of up to 500 workers from around the world
Naturally, a project of these dimensions involves a variety of challenges, such as the limited space available and coordinating innumerable concurrent tasks. This is where teamwork and precise planning are required. The time schedule is an essential guide although with a life of its own, many decisions which have a huge impact need to be made within just hours. Even when everything has been run through in advance, many factors only arise after the blast furnace has been ramped down and during demolition.
The interaction between the various external companies also was seamless. If you consider that several companies who are normally competitors were required to cooperate, this could not be taken for granted.
Communication is the key to smooth cooperation.Christoph Kreindl, sub-project manager
Incidentally, at peak times up to 500 workers were present on site. As well as Austrians and Germans, the international workforce included many Portuguese, Croatian, Czech, Slovak, Polish and Hungarian employees.
The human factor
The success of a project depends upon the people driving it. In addition to the core team of 30, a total of 250 to 300 voestalpine employees were involved over the duration of the project, because in terms of planning, the relining of the blast furnace was 100% a voestalpine project.
I'm fascinated by the know-how that we possess within voestalpine. There are so many smart people in the Group. And it's a delight to see what we can achieve by working together.Bernhard Kaiser, project manager
But as we all know, once one project is completed the next begins: the next major investment is already in sight with the planned relining of large blast furnace A in 2018. However, with our experience to date, we are well equipped for this task.
Facts and figures:
- 5,000 m³ of water was used for cooling (which corresponds to 36,000 bathtubs). Six weeks after ramping down, temperatures of 54°C were still measured in the base.
- 51,000 refractory bricks weighing a total of 1,100 tons were used in relining the furnace. The heaviest refractory brick weighed 2 tons and measured 280 x 70 x 60 cm. Around 260 m³ of refractory bricks were exchanged in the Cowper stove alone.
- The entire work of replacing the refractory bricks took about 30,000 man hours.
- The piping measures a total of approximately 6,150 m in length. 20,000 weld seams were needed to install the piping.
- Exchanging the casing required another 7,200 m of weld seams.
- 7,500 kg of welding consumables sourced from the voestalpine Böhler Welding Group GmbH were used in the welding.
- The electricians laid (and connected) some 63,000 m of cables.
- Around 500 tons of steel was used to construct the burdening conveyor (including for blast furnace 5).
- 30,000 man hours were required purely for the refractory work on blast furnaces 5 and 6.
A personal look back at the relining process:
First off, I'm just proud! The team was simply great, our cooperation was seamless. There were several problems in exchanging the casing, but we solved that. I'm hugely relieved!Andreas Mairwöger, BTT, sub-project manager
I was working on the burdening conveyor, adjusting the weighing mechanism. What I won't forget is being part of a team, even working with external companies. I was never worried—I knew who was doing the work.Gernot Hartinger, BTA, industrial electrician
It was technically complicated but we learned a lot from blast furnace 5. We know that we can overcome all problems when we stick together. And that's how we even managed to exchange the steel jacket!Bernhard Kaiser, BVK, project manager
My crew and I were responsible for all the transport to and from the worksite. Sometimes coordination was a little difficult, but we also got to grips with that. However, I'm pleased to be back to normal operations.Gerald Pum, BTH, foreman/service