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Magazine: Nitrogen+Syngas

Incident No. 1: Leak in nozzle in urea reactor bottom

High pressure urea equipment often has lined nozzles. A lined nozzle is a full strength carbon steel nozzle that is protected against carbamate corrosion by a 5 or 6 mm thick stainless steel liner plate, which is welded to the carbon steel nozzle on either end. This design is however very vulnerable to fatigue cracking due to the difference in thermal expansion between the austenite liner and the carbon steel nozzle. History shows that such a design will lead to cracking in the long term. The following case study reports on a serious incident in a urea plant where a leak in a urea reactor nozzle caused a plant shutdown but could have resulted in rupture of the high pressure vessel.

Nitrogen Industry News Roundup

Maire Tecnimont subsidiary Tecnimont SpA has finalised its $350 million EPC contract with Egypt Hydrocarbon Corp. (EHC) for the construction of a new ammonia plant at Ain Sokhna. The preliminary contract was announced in September last year. The contract for the plant, which will produce 1,320 t/d of ammonia, also includes extensive utilities and offsite facilities. Project completion is scheduled for 36 months from the effective contract date, which will be triggered by financial closure of the project. Project finance is being arranged by the Italian export credit agency SACE and the US EXIM Bank. The ammonia will be used to feed an ammonium nitrate plant, already existing and in operation in the same industrial facility, also owned by EHC.