Reactor replacement

The reactor units at the POX methanol plant in Leuna, Germany, are being replaced. TotalEnergies Raffinerie Mitteldeutschland, operator of the plant and Europe's largest methanol producer, commissioned Mammoet to replace the first and the second reactor.

A complete shutdown of the plant was not possible as a required production volume had to be guaranteed; so only one reactor at a time could be removed and replaced.

Mammoet concluded that the most efficient solution to replace the reactor unit would be to use a Liebherr LR 1750 crawler crane. It can lift and move a load of 140 t onnes, as well as perform all other lifting operations. This was necessary because, due to space limitations, the pre-assembly and storage area for the components was located approximately 200m from the installation position.

In order to safely lift the steel construction module, completely fitted with equipment, whose centre of gravity could not be precisely calculated (but was off-centre) Mammoet used COGAS winch system with four-point rigging.

According to Mammoet the winch acts as a centre-of-gravity balancing system. The operator controls the winch via 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.

The mobilisation and preparation of the crawler crane took place over the New Year.

First, the old reactor and the old sub-reactor were removed one by one, transported by the crawler crane to the laydown area and stored there. Special demolition chains were used for rigging. The heavy-duty rigging was then modified, and the new components lifted into place with the LR 1750.

The new sub-reactor, weighing 120t, was already stored upright at the preassembly area. It was attached, lifted, moved around 200m to the plant on the hook of the crawler crane and pivoted into place. The new reactor, weighing 140t, followed in the same way.

Finally, the steel construction module, weighing 100t, was lifted and moved safely into position using the Mammoet COGAS winch. All work was completed ahead of schedule.