Urea Reactor

Achieve superior urea reactor lifetime with Safurex® steels

The Challenge

Urea Reactor lifetime differs substantially between different technology concepts. 

To ensure superior lifetime of the urea reactor in both Stamicarbon and non-Stamicarbon plants, we design urea reactors with standard 5mm Safurex® stainless steel lining and Safurex® stainless steel internals.

A thinner Safurex® liner provides a significantly longer expected lifetime of the urea reactor compared to thicker austenitic stainless steel liner materials. 


Liner thickness and material Corrosion allowance Corrosion rate
5 mm Safurex® 2 mm 0.01 ~ 0.02 mm/y
10 mm 316L UG 7 mm 0.2 ~ 0.3 mm/y
8 mm X2CrNiMo25-22-2 5 mm 0.1 ~ 0.15 mm/y

Longer equipment lifetime can be achieved with a thinner Safurex® liner despite the occurrence of harsh process (upset) conditions such as, for instance, loss of passivation air or longer block-ins of the high-pressure (HP) synthesis up to a couple of weeks. 

ADVANCE DESIGN Safurex® Urea ReactorThe Solution

Stamicarbon offers several solutions for the renewal of urea reactors:

  • Replacement of the end-of-life urea reactor with a new urea reactor made of Safurex® steel liner and internals
  • Partial relining of the existing (316L UG lined) urea reactor with X2CrNiMo25.22.2 or Safurex® liner material based on Stamicarbon relining philosophy, including welding and relining procedures developed by Stamicarbon
  • Complete relining of a urea reactor (316L UG, X2CrNiMo25-22-2 or Titanium liner) with X2CrNiMo25-22-2 liner material. In certain cases, we can offer relining with Safurex® liners
  • Revamping the existing reactor by adding additional volume either using Safurex® or X2CrNiMo25-22-2 liner plates 
  • Improving reactor conversion of the existing urea reactor by installing Safurex® high-efficiency or Siphon Jet Pump (SJP) trays
  • Improving the safety of the existing urea reactor by replacing radioactive level measurement system with radar and implementation of a state-of-the-art leak detection system

If you are unsure whether your urea reactor should be relined or replaced, our experts will help determine the solution based on your situation. 

Our reactor design and materials are customized for different applications. We consider the design and material of the carbon steel shell and use low- or high-strength steels based on the client's requirements. 

Stamicarbon offers a full scope of replacement for urea reactors, including all necessary instrumentation, such as:

  • Radar level measurement
  • Leak detection monitoring system
  • Thermowells and thermocouples 
  • Pressure transmitters 

We also offer replacement solutions for the adjacent piping in the HP synthesis section. 

As a urea technology licensor, Stamicarbon is also able to calculate possible process improvements based on the new configuration of the reactor design and those can be contractually agreed upon as process guarantees at the battery limits of the reactor (e.g. conversion rate (%) or urea content (%)).

Advantages of the Safurex® Urea Reactor

Reactor trays have a proprietary design and are made from proprietary material Safurex® duplex steel. 

Receive the following advantages:

  • Reduced need for inspections and maintenance due to the high corrosion resistance of Safurex® steels 
  • Longer lifetime of the urea reactor  
  • Improved reactor conversion by optimized design of the trays
  • Increased plant safety with the possibility to use a radar level measurement device and the implementation of a state-of-the-art leak detection system
  • Opportunity to increase block-in periods thanks to the resistance of Safurex® steels to active corrosion

ADVANCE DESIGN Safurex® Urea ReactorAbout Urea Reactor

The urea reactor is a vertical Safurex® steel lined high-pressure carbon steel vessel. The mixture of ammonia and carbamate solution from the HP carbamate condenser or pool condenser, along with gaseous ammonia and CO2 from the HP stripper, enters the bottom of the reactor. 

In the urea reactor, the conversion of ammonium carbamate into urea approaches its equilibrium. Meanwhile, the remaining reactants and converted products rise to the top and are transferred into the HP stripper in stripping urea plants or transferred to the medium-pressure (MP) / low-pressure (LP) section in conventional urea processes. 

The purpose of the urea reactor is to provide a large volume to allow sufficient residence time for the reactants to reach equilibrium. This is needed because the conversion of carbamate into urea takes much longer than the formation of ammonium carbamate. 

Urea Reactor Replacement in Non-Stamicarbon Plants

Stamicarbon offers reactors for all urea processes.

Replacement of any HP vessel in urea synthesis is an opportunity to debottleneck the plant.

Therefore, we perform process plant assessments before replacing the HP equipment to identify what modifications should be addressed in the new vessel's design. 

Contact us for more information about our urea reactors.


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