Please Note: The information on this page is augmented by an excellent resource for more detailed technical information relating to urea and nitrogenous fertilisers, provided by ureaknowhow.com.
UreaKnowHow.com acts as an information source and an information exchange platform amongst all nitrogen fertiliser plants. The exchanged information is of a non-confidential nature and covers operational and maintenance issues, safety hazards and risks, incidents and troubleshoot cases, revamp technologies and innovations, etc. The site also provides access to a network of over 7,500 Managers and Engineers working in the Nitrogen Fertiliser Industry representing all nitrogen fertiliser complexes worldwide.
Ureaknowhow.com provides several resources that are available for everyone to access. These include limited access to a library of technical papers, a range of informative videos, and to round table forums.
Considerable additional value can be obtained by registering to become a member. This is free for operators, engineers and managers working in and for urea plants, ammonia plants and other nitrogen fertiliser plants, individual technical consultants, employees of governmental organisations, plus employees of UreaKnowHow’s Partners and Solution Providers. When you enlist as a Member you are able to participate in more than 2,100 Round Table discussions with other engineers, access the world’s largest Urea E-Library, and receive biweekly UreaKnowHow.com’s Newsletter. You can learn the latest innovations and developments, present your own troubleshoot cases, participate in benchmark studies, enter the Job Portal, the Used Equipment market and Incidents Databases, expand your network and have access to our Nitrogen Fertilizer Plants Overview which includes all urea plants worldwide including China.
In addition, UreaKnowHow.com runs a wide range of fertiliser training Programs designed for engineers and managers, marketing and business development managers and safety, health and environmental managers. The programs offer information about the various types of fertilisers, the various fertiliser production technologies and fertiliser finishing technologies, the role of fertilisers, the market trends and players in the fertiliser business, how your products and services fit in the fertiliser market and the hazards of the various fertilisers and fertiliser production technologies. The UreaKnowHow.com fertiliser training modules are part of the Fertilizer Academy.
Urea – Properties
Pure urea is a white crystalline solid. The melting point of urea is around 133 °C, decomposition of urea starts before reaching ist boiling point. Urea usually smells somewhat ammoniacal.
The relatively low specific density, compared with that of other fertilizer materials, must be considered in calculating storage space requirements. For instance, storage space requirements per unit of nitrogen are about the same for urea as for ammonium nitrate because the higher analysis of urea is offset by its lower specific density. As urea has a relatively low specific gravity, care needs to be taken to allow for this when formulating blended products. This characteristic also needs to be allowed for in relation to storage capacity planning – any given tonnage will require more volume.
Urea is less hygroscopic than ammonium nitrate but more hygroscopic than ammonium sulphate; it requires protection from humid atmosphere in some climates. The coating of prilled urea with clay, oil, or other coating agents gives relatively good protection. Many producers add small amounts of formaldehyde to the urea melt just before prilling and obtain very satisfactory results in storage. If the product is properly dedusted and the producer has made good prills with high impact and crushing strengths, it is possible to ship uncoated bulk urea long distances with no problems. Data on the critical relative humidity and solubility of urea can be found in literature. Urea has a low thermal conductivity and can provide a good insulating effect. Biuret is a chemical compound with the chemical formula (H2NC(O))2NH, Figure 1. It is a white solid that is soluble in hot water. Biuret results from the condensation of two equivalents of urea. As such, it is an undesirable impurity in urea-based fertilizers. As biuret is toxic to plants, its percentage in urea and urea-based fertilizers must be kept low.
Guidance for the storage, handling and transportation of solid mineral fertilizers, Fertilizers Europe, 2022
Related IFS Proceedings
131, (1972), Some Fundamental Aspects of Urea Technology, S M Lemkowitz, M G R T de 166, (1977), Urea Stripping Process – Stripping Technology, Phase Equilibria and Thermodynamics, P J C Kaasenbrood, H A G Chermin, Cooker, P J van den Berg
167, (1977), An Integrated Process for Ammonia-Urea Manufacture, V Lagana, U Zardi
206, (1982), Materials of Construction for the Nitric Acid Process, K Nutall, A R Reid
257, (1987), Rationale for Mixed Ammonium Nitrate – Urea Fertilisers and Assessment of Granular Products, M K Garrett
582, (2006), IPPC: The BAT Reference Document (BREF) for the Manufacture of Ammonia, Acids and Fertilisers, B Serr
725, (2013), Urea-based NPK Granulation – Examination of Constraints and Potential Solutions, S R Doshi
770, (2015), World-Wide Trends in Urea Process Technologies, J M G Eijkenboom, M J Brouwer
805, (2019), The Carbon Footprint of Fertiliser Production: Regional Reference Values, A Hoxha, B Christensen
830, (2019), Principles and Applications of a Directory of Urea Safety Incidents, with Case Studies, M J Brouwer
Need more information?
If the information you need on this topic is not on this page, use this button to access the resources and forum of ureaknowhow.com. You will be asked to register, but this is free for most.