Steuler has been carrying out the refractory maintenance work at the Ebenhausen facility since 2007. The range of services encompasses consultation, engineering, manufacture, delivery, dismantling and installation work as well as the recovery and recycling of the used refractory materials.
In addition to the routine items – rotary kiln, afterburner chamber and boiler – this summer‘s overhaul included for the first time since incineration line VA 2 went into service, maintenance of the cupola, which is the subject of this report.
Cupola is the term given to a domed structure with a single apex. In the case of the GSB plant, it involves a half-cupola with a diameter of around six meters directly connected to the boiler section via a domed section.
Professional and timely execution while ensuring industrial safety were the highest priorities, with the team having to master the complex technical requirements under extreme physical conditions. In order to ensure that the overhaul was completed as quickly as possible, it was necessary to perform the furnace work in parallel and to optimise access to the plant.
Due to the installed height of around 20 meters above ground, a stable working platform was necessary in order to transfer the removed materials externally via special rubble chutes into ground-level skips rather than internally through the afterburner chamber. An external lift was installed to transport materials in addition. These measures made it possible to carry out installation work on the cupola, afterburner chamber and rotary furnace in parallel and at the same time.
For the cupola renovation, a total of 220 pallets of material were raised to the height of the manhole at nearly 20 meters by means of a transport platform, temporarily stored and installed. In order not to exceed the load capacity of the work platforms, it was necessary to first unload half of the bricks from the pallets.
In tropical conditions, with midday temperatures exceeding 30 °C and temperatures in the plant during the first week of dismantling still over 50 °C, our installation technicians began work on breaking out the refractory from the apex of the cupola. Layer for layer, the bricks were carefully removed.
In addition to the physical demands, the geometry of the cupola represented a major test of the craftsmanship and technical skills of our team. Working with extreme precision and foresight were essential for this structure.
The lining work was performed with shaped bricks specially manufactured for GSB, starting at the upper plinth level. In total, more than 20 differently shaped bricks were required for the cupola, making the costs for modelling correspondingly high. Except for the cement, no monolithic materials needed to be used.
The total order volume (rotary furnace, afterburner and cupola) was worth 1.0 million euros to Steuler Refractory Linings with construction work (using 35 installation technicians at its peak) taking almost 4 weeks.
Our special thanks for completing the work in a professional and timely manner go to the entire installation crew under the supervision of Christoph Litzelmann, all the colleagues from our Design Department who were involved and last, but not least, all those at GSB for their hard work and support.