TotalEnergies Raffinerie Mitteldeutschland GmbH is one of Europe's largest menthol producers. Because of the volume of menthol produced, strict production numbers need to be met. These production targets mean that the reactor units – consisting of a reactor, sub-reactor, and heat exchanger – at its POX methanol plant in Leuna, Germany, couldn't shut down when they needed replacement.
Only one reactor at a time could be removed and replaced. A flexible and safe solution that would disrupt operations as little as possible was required. In order to complete the reactor replacement project, TotalEnergies needed to find a partner capable of completing the project. They chose Mammoet to replace the first and the second reactor.
Liebherr LR 1750 provides an efficient solution
Mammoet carried out a preliminary engineering study to find the most efficient solution. The study found that a Liebherr LR 1750 crawler crane would be the best crane for the job. It can lift and move a load of 140 tonnes as well as perform all other lifting operations. The job site also had space limitations. The pre-assembly and storage area for the components was located 200 metres from the installation position.
The next issue the project had to combat was lifting steel construction modules with a centre of gravity that could not be precisely calculated but was, in any case, off-centre. Mammoet used its COGAS winch with four-point rigging in order to move these off-centre modules.
The COGAS winch acts as a center-of-gravity balancing system. The operator controls the winch through a remote control and can change the length of the individual rope strands so that the crane hook exactly matches the component`s centre of gravity.
Because Mammoet was the single contractor in charge of everything from engineering and crawler crane delivery to the execution of the job, the team reduced the number of interfaces and contributed to a safer project while the plant was in operation.
Preparation and cooperation ensure early completion
In order for the crane to start lifting on time, the mobilization and preparation of the crawler crane took place over the New Year. Despite the holidays, the team's dedication meant that the crane was ready to lift on time.
First, the old reactor and the old sub-reactor were removed one by one, transported by the crawler crane to the laydown area 200 metres away, and stored there. Special demolition chains were used for rigging. The heavy-duty rigging was then modified, and the new components were lifted into place with the LR 1750.
The new sub-reactor, weighing 120 tonnes, was already stored upright in the pre-assembly area. It was attached, lifted, moved 200 metres to the plant on the hook of the crawler crane, and then pivoted into place. The new reactor, weighing 140 tonnes, followed in the same way.
Finally, the steel construction module, weighing 100 tonnes, was lifted and moved safely into position using the Mammoet COGAS winch.
Mammoet completed the project in a safe and timely fashion ahead of schedule.
