Work on the dismantling of the 150-metre Delimara power station chimney will commence at the start of next month, following this morning’s unanimous approval by the Environment Resources Authority on the procedure for the decommissioning of this structure.
The development follows the phasing out of the use of heavy fuel oil at the Delimara plants, which switched to gas as from last April.
Decommissioning will follow a set of environmental safeguards to ensure there was no contamination from residual sooth or ashes in the chimney
During a presentation to the ERA board, Enemalta executive chairman Fredrick Azzopardi outlined the procedure which will be followed to dismantled the chimney, which will be carried out by Italian contractors which were chosen following a public call issued last December.
Though the planning authority had already given the go-ahead, today’s decision was meant to ensure that the decommissioning would follow a set of environmental safeguards to ensure there was no contamination from residual sooth or ashes in the chimney.
From a technical aspect, Enemalta today surrendered what is known as the Integrated Pollution and Prevention Control permit (IPPC) which allowed it to make use of the chimney.
Built in 1992, the Delimara 1 plan, included two HFO boilers, two 60MW steam turbines as well as the 150-metre chimney made of reinforced concrete.
The chimney structure comprises a cylindrical concrete shield rising up more than 50 storeys, with a base diameter of 12 metres. The concrete walls are two metres thick at the bottom and 60 centimetres on top. Inside the concrete structure, there are two 2.3 metre steel exhaust pipes that emit the smoke produced by the oil-fired boilers.
The dismantling will start with the lowering of these two steel pipes and all metal structures inside the chimney, using strand jacks, so that they can be dismantled on the ground. To demolish the outer structure, the contractors will erect an auto-lifting platform on five steel columns all the way to the top.
Remote-controlled demolition robots on top of this platform will then be used to demolish the first 1.5 metres of the concrete walls. The platform will then be lowered 1.5 metres for the demolition robots to continue the demolition. This process will be repeated approximately 80 times until the chimney is lowered to 35 metres. At this point, the platform will be dismantled and the remaining part of the stack will be demolished using a high reach demolition excavator from ground level.
To demolish the outer structure, the contractors will erect a platform rising on five steel columns all the way to the top. Remote-controlled demolition robots on top of this platform will then be used to demolish the first 1.5 metres of the concrete walls. The platform will then be lowered 1.5 metres for the demolition robots to continued. This process will be repeated approximately 80 times until the chimney is lowered to 35 metres. At this point, the platform will be dismantled and the remaining part of the stack will be demolished using a high reach demolition excavator from ground level.
At this point, the platform will be dismantled and the remaining part of the stack will be demolished using a high reach demolition excavator from ground level.
The dismantling process is expected to take a year.