It truly was a masterly logistical and technological performance. Everything had to be just right – from the water level of the River Elbe, to the strength of the wind at the Lippe Plant when the boiler was replaced via the roof of the power station, 40 metres above the ground. 42 trucks had to be deployed from Munich just to transport the special crane needed for this task. The fact that everything ran so smoothly can, above all, be put down to the meticulous planning work and extensive experience of all those involved.
Having been used for 35 years, a section of the heat recovery boiler at REMONDIS’ fluidised-bed combustion plant had to be replaced. To be able to do this, all membrane walls and a total of three heat exchanger bundles were removed and replaced during the scheduled inspection of the plant that took place between 24 September and 12 October 2015. What sounds so simple is, in fact, pretty much like carrying out open-heart surgery on an industrial facility involving weights exceeding 100 tonnes.
The replacement boiler was transported to Lünen via the River Elbe, the Mittelland Canal, the Dortmund-Ems Canal and the Datteln-Hamm Canal.
The transport of the replacement boiler was itself a logistical feat. The first stage of the route was by road when the boiler was transported from the manufacturer’s plant in Hohenthurm to Aken an der Elbe in the German state of Saxony-Anhalt. It was then taken by ship on the River Elbe, whose water level had to be just right to enable the 100-tonne boiler to be transported. Gradually it made its way along the canals via Magdeburg to Lünen where it was loaded onto a special vehicle. Around two hours were needed to travel the short distance – just 3 kilometres – between the harbour in Lünen and the Lippe Plant.
A feasibility study had already been carried out beforehand to work out how the special 650-tonne crane could be best set up at the construction site. Once the complicated preliminary planning process had been completed, a concept was then drawn up over the winter months of 2014/15 to establish how exactly the boiler should be removed and replaced. The decision was made to assemble as much of the boiler as possible beforehand rather than assemble it on site as the power plant has such a narrow structure. By doing so, the turnaround period would be much shorter and the power plant would be up and running and able to accept waste from its customers for thermal treatment much faster. Moreover, far less natural gas would be needed. The auxiliary boilers run on natural gas are used to produce process steam as long as the power plant is shut down as it supplies the companies at the Lippe Plant with steam 24/7, 365 days a year.
One of the striking features of the power plant is its flue gas arch that acts as the afterburner. This first had to be taken down so that the old boiler could be extracted from the plant and replaced with a new preassembled boiler.
Every day, up to 60 operatives carried out their tasks to ensure that the boiler was replaced within just 15 working days. All the connecting pipes first had to be disconnected and then welded back on again after the new boiler was in place. Doosan Babcock Hohenthurm, an old established company from Landsberg near Halle in Saxony-Anhalt, had been given the task of drawing up a concept that ensured as much of the boiler could be pre-assembled as possible and then installed in the plant in as short a time as possible.
The cranes began their work on Wednesday, 30 September. The installation of the new boiler was completed just 4 days later at 10pm on the Day of German Unity. With a total of ca. 14,000 metres of piping, several thousand welded joints and weighing approx. 100 tonnes, this boiler truly is the heart of the power plant’s steam production system. Here’s to the next 35 years!