CORROSION RATES IN A FERTILIZER PLANT AND THE STRUCTURAL FAILURE OF A CONVEYOR GANTRY

摘要

Subsequent to the structural failure of a gantry supporting a conveyor, transporting single super phosphate in a fertilizer plant, corrosion rates of mild steel was studied. Coupon corrosion rate measurements and derived estimations of time-to-failure lead to a reasonable correlation to the collapse of the conveyor gantry. These correlation results now provide further assistance, via a benchmark, for monitoring highly corrosion prone structures such as those in the fertilizer industry. It now appears conceivable that these structures, without maintenance, may have reached a critical failure point after about 30 to 40 years. It was concluded that annual audits comprising inspections of structures at risk, condition monitoring of plant items by ultrasonic thickness testing, advice on the nature of any repairs required and the condition of coatings should be undertaken. Such audits formalising a comprehensive holistic protection programme to mitigate the rate of ongoing corrosion.