Coating urea prills (granules) with a water-insoluble, semi-permeable, or impermeable (with pores) material delays the release of nitrogen from the urea. In this discussion, neem-coated urea is highlighted as having great potential for increasing the efficiency of urea.
Among the many problems that threaten the daily operation of a urea plant, fluid leakage is perhaps the most common, especially the leaking of high pressure flanges in the urea synthesis section. A high-velocity jet emerging from a flange due to a failed gasket, a pinhole in an elbow, corroded threads of a level transmitter, etc., are familiar scenes that the maintenance crew encounters and must rectify.
Control of the process conditions of the MP absorber is one of the key control parameters in a Saipem urea plant. CO2 carryover to the ammonia receiver is not permitted in the process as it will create corrosion problems and upset conditions in the ammonia recovery and pumping system. This round table discussion considers the problems and solutions in this process section.
Where possible, fertilizers should be stored in closed storage to protect the product from the weather (sun, rain etc.). The ideal storage conditions for urea granules in the summer season in the Gulf region are discussed.
Flares in urea plants are designed to improve the site’s safety performance by capturing and burning ammonia emissions from safety release points. This will prevent/reduce ammonia emissions from entering the environment and in turn reduce ammonia risks. Flares are becoming more common in new urea plants, but are they the optimum solution to improve safety and reduce environmental risks?
Pressure transmitters have become essential parts of virtually all urea plants. This discussion looks at a case where a plant is experiencing frequent faults with a reactor pressure transmitter. The urea industry shares its experiences and solutions.
A discussion about the causes for a change in urea product colour. Stainless steels exposed to carbamate containing solutions in the urea synthesis section can be kept in a passive state by adding a minimum amount of oxygen. If the oxygen content drops below this minimum, active corrosion starts, which can be identified by a shiny silver colour on the surface.
Preservation covers the method of protection and preventative maintenance carried out on equipment and systems before and after they are put into use. In power plants, fertilizer units and refineries, expensive equipment like turbines, chillers, power generators, boilers, condensers, panels etc. begin to rust and corrode when in storage or during shutdown or even when in operation due to the presence of excess moisture in the air. Proper downtime procedures are extremely important. In this discussion, preservation and its importance is discussed by urea plant experts.
The waste water treatment section in a urea plant processes the water containing NH3-CO2 and urea from the vacuum system in the evaporation section. This discussion looks into the possible root cause of problems with the concentration in the waste water section feed tank of a urea plant and the off-grade condensate produced.
In a urea plant, too much carbamate solution recycle back to the synthesis section will increase the amount of water in the synthesis and will negatively influence the reactor conversion figures. Fouling in the recirculation section can sometimes cause these operational problems, but how can fouling be identified as the root cause of a problem?