Condenser repair -

Repair of condenser tube inlet erosion / corrosion damage with ENSIGN Venturi Inserts

A power station was experiencing severe condenser tube inlet erosion / corrosion in three main condenser units. One unit was already beyond repair and required a full re-tube at huge expense. The other two units had suffered up to 30% wall loss at the tube inlets after only three years in service, with each unit experiencing different wear rates.

Two custom sized ENSIGN Venturi Inserts were developed to match the erosion occurring at each individual condenser unit and 40,000 custom inserts were then installed in the badly eroded tube inlets. An additional 20,000 standard sized Venturi Inserts were installed in the recently re-tubed third unit.

Given the very rapidly occurring erosion / corrosion and the fact that a previous installation of metal inserts had resulted in end step erosion the plant engineers expected that longer inserts would be required fairly quickly. This however proved not to be the case with regular tube inspections revealing that replacement was not necessary after eleven years in continuous service.

Four years additional years in service are anticipated before the next major tube inspection enabling the generator to avoid two full condenser re-tubes, considerable down time and any additional remedial action for at least 15 years.

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