Power Plant Niederaußem

Life cycle management for the 200 m high natural draft cooling tower of the BoA unit K

The lignite power plant Niederaußem has a gross electrical capacity of over 3600 MW. In 2002, the newly erected K was taken into operation by the RWE AG. The block K reaches new dimensions, both due to its natural draft cooling tower and also from a building perspective. With its height of 200 meters, it was the world's tallest structure of its kind for some years. In addition to its function of cooling the cooling water, the cooling tower is also used for the disposal of the cleaned flue gases. An ”acid-resistant” High Performance Concrete was first developed and used - to be able to relinquish the time consumption and costs of the mandatory coating of the cooling tower shell inner surface, which was an innovation.

With the exceptional dimensions of the structure and the use of new concrete, new aspects in construction techniques were developed. This was as far as possible taken into account as part of the design and sizing of the cooling tower supporting structure as well as by diverse investigations of the concrete in the laboratory.

In order to safely control the not-to-be-excluded remaining risk via calculations and lab experiments for technical new developments that remained beyond, a long-standing monitoring of the executed cooling tower supporting structure was conceptualised by RWE Energie AG, ZPP or the predecessor company and further involved parties from the years of 1998 and 1999.

In the years 2000 to 2002, the cooling tower monitoring system was installed on behalf of RWE Power AG and put into operation. Using additionally performed, regular inspections, events, such as damage occurs can be detected as early as possible. In order to identify and assess causes of damages, a correlation with the measured influences on the building and possible changes in the material (eg in the form of a subsequent hardening of the concrete shell) can be performed through the building monitoring. Due to these findings, remedies can be planed and implemented in time and additionally be developed to revision time spans.

Life-cycle management was carried out on the cooling tower K since 2002 continuously by ZPP. The knowledge and experience gained had an input on the VGB Guideline 613 ”Guidelines for the lifetime management of reinforced concrete cooling towers in power plants”. Through this, even more new cooling towers can profit from the success in Niederaußem with life-cycle management.