Timely inspection of structural supports for fossil fired boilers and systems

All generating plant systems require structures of varying complexity to house and support the boiler and its ancillaries. Whilst major structural incidents are very rare, deterioration within these structures can lead directly to on-line loss of process efficiency or availability. The experience drawn from many years of site inspection shows that the ultimate performance of the structure is significantly influenced by the operating, maintenance and fuel regime applied to the boiler systems. In particular, the life of supporting connections and members within boiler and duct enclosures are very dependent on maintaining control of design environmental temperatures, the applied loads and their distribution. Currently, unlike other aspects of the generating system, the general integrity of the support structure cannot be comprehensively reviewed by on-line diagnostic systems. Targeted and informed visual inspection, backed by appropriate site measurements is necessary to establish trends and to maintain the systems according to need. The paper briefly considers structural design for boiler support structures, and principal ancillary systems. The influence of temperature, imposed operational loads and control of thermal expansion are discussed, with appropriate case studies