Tag: Ureaknowhow

In the case of a failure in a urea plant, when the problem is expected to be solved within a short period, the high pressure synthesis section is typically blocked in (referred to in this article as reactor hold up). All input and output streams are closed and the synthesis section remains partly filled with a solution consisting of ammonia, CO2, water, ammonium carbamate and of course urea. Several risks can occur during this blocked in situation.

A discussion about the high-pressure CO2 stripper and how to solve the problem of a high temperature in the bottom of the stripper.

Dust formation in the granulator can adversely affect stream time. There are several reasons for increased dust in the fluid bed granulator. No formaldehyde or less formaldehyde injection, lower bed level in the granulator, lower concentration of urea melt to the granulator, a higher pressure in atomisation (sprayer) air and a higher pressure in the urea melt header are all factors which can play a role. This article discusses increased dust level and its causes.

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.