The following case study reports on a serious incident in a urea plant where a leak in the weld overlay in the urea reactor bottom resulted in a costly plant shutdown and near miss of rupture of the high pressure vessel. It is known that carbon steel can corrode with rates of 1000 mm/year not taking into account erosion due to flashing. The impact of the NH3/CO2 ratio on the corrosion rate is questionable.
Although the Covid-19 pandemic has been the big story in every market this year, the disruption and dislocations that this has caused have masked some of the bigger trends in the urea market, such as the revival of Chinese exports and India’s push for self-sufficiency.
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.
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.
Alistair Wallace, Head of Fertilizer Research, Argus Media, assesses price trends and the market outlook for nitrogen.
Merchant ammonia capacity, only a relatively small 10% of overall ammonia demand, has been expanding in recent years and was already in surplus even before the current Covid crisis, but longer term a shortage of new projects may tighten the market again.
Prices remain at low levels, in part because of oversupply due to new plant start-ups. However, there has also been a contraction in demand, especially for technical ammonia – industrial markets for ammonia in China and East Asia have been badly affected.
Market Insight courtesy of Argus Media
Demand from horticulture has seen the use of water-soluble phosphates rise globally to almost one million tonnes annually. We assess the market and its growth prospects, identify leading producers and highlight recent product innovations.
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