How to increase safety and reliability standards in a urea plant

Mark Brouwer, ureaknowhow, The Netherlands

An overview of construction materials and corrosion issues in the high pressure synthesis section of urea plants

Giel Notten, Consultant, The Netherlands

Ammonium carbamate, the intermediate product in manufacturing urea, is very aggressive and has to be considered as a strong (BrØnsted) acid.

The corrosive behaviour of the synthesis environment has forced urea licensors and manufacturers, as well as stainless steel manufacturers, to put a lot of effort into the development of suitable materials of construction, with strict demands on quality, chemical composition as well as microstructure.

In the initial phase of urea manufacturing lead and silver was used as liner material in High Pressure equipment.

In the early 1950’s of the previous century it was  discovered that the supply of oxygen can reduce corrosion rates of stainless steels by passivation in urea synthesis conditions. Since this period (Urea Grade) austenitic stainless steels have been used for equipment of the urea synthesis section.

To diminish the amount of oxygen, since the 1990’s super duplex stainless steels have been used. As well as stainless steels, materials like titanium, zirconium and tantalum have been applied.

From each of these materials, their advantages, disadvantages and typical corrosion failure modes are discussed, followed by the future expected trends of the various licensers.

This presentation carries 2 BASIS FACTS CPD (HS) points for UK attendees

Smart nutrient management strategy for rice: Sustainable production potential and its physiological bases

Zhuo Xu, Wageningen University, the Netherlands

Deriving fertilizer recommendations for cocoa: an offtake model approach

Ekatherina Vasquez-Zambrano, Wageningen University, the Netherlands

This work involved the development of a cocoa N, P, and K offtake model based on nutrient export and immobilisation in the tree to provide a more informed fertiliser application recommendation. Cocoa production in West Africa has increased over the years, yet yields are stagnant due to limited fertiliser use, poor maintenance, and inadequate pest control. Moreover, the knowledge on cocoa mineral nutrition is still limited, with outdated existing and inconsistent fertiliser recommendations across countries and regions. In the model, total N, P, and K requirements are calculated based on target yield, nutrient concentrations in the crop, and amounts immobilised in woody shoots and roots.

Dipping with wastewater-derived struvite as a safe method to accelerate paddy rice seedling growth in Madagascar

Elden Willems, KU Leuven, Belgium

The research of overall winner Elden Willems explores the potential for using struvite to improve N and P use efficiency in rice and also reduce seedling toxicity linked to acidity and ammonium osmotic stress. In practical terms, N and P dipping with struvite could improve paddy rice yields and reduce the need for conventional fertilisers, contributing to agriculture sustainability. 

His key findings were that struvite, as a waste-derived N and P source, can partially replace conventional fertilisers. At the same time, the slow nutrient release from struvite could be more aligned with rice nutrient demand and therefore allow for a greater N and P uptake when compared to MAP, a highly water-soluble and acidic phosphate source. Seedling toxicity was reduced. Added benefits are the resource use efficiency of deriving a fertiliser from wastewater, and the potential to benefit rice farmers worldwide.     

BASIS FACTS CPD points for UK attendees have been applied for