Equipment Relining

Extending the lifetime of your urea reactor at a minimal cost

The Challenge

Urea reactors in many plants remain in operation for over 20 years. Yet, with time the protective liner on the reactor wall becomes thinner, making the vessel more vulnerable to corrosion caused by ammonium carbamate.

Does that mean you need to replace the whole vessel once corrosion is detected? Not necessarily. Often a partial relining can provide a safe, reliable, and cost-effective way to extend the lifetime of your urea reactor. 

Why Equipment Relining?

Corrosion in the top section of a urea reactor typically determines its service life, with most corrosion issues occurring at the gas-liquid interface.

Relining the top hemisphere becomes a cost-effective and time-saving alternative for extending its lifetime instead of purchasing a new reactor. 

A partial relining could help resolve the thinning of the protective liner related to the following issues: 

  • Overall corrosion attack and condensation corrosion in the splash area 
  • Strain-induced intergranular corrosion (SIIC) cracking in the gaseous phase under the influence of condensation corrosion and strain
Test assembly of pre-fabricated hemi-head
Test assembly of pre-fabricated hemi-head

Good maintenance is essential for the smooth operations of your plant. With equipment relining, you can extend the lifetime of your urea reactor with minimal investment and gain access to expert technical assistance at every step of the procedure.  

Gain the following advantages:

  • Minimal execution time of the relining project
  • Minimal downtime and production losses
  • Minimal capital expenses 
  • High-quality tailor-made solutions
  • On-site supervision by our experts  

Our Solution

Stamicarbon offers relining solutions tailored to clients’ needs and specifications.

With careful planning and preparation, a complete installation of an upgraded corrosion-resistant layer on-site can be done during the planned shutdown of the plant.

Removal of the old liner
Removal of the old liner

Every relining solution is different, but we generally follow this approach:

  • Prepare a dedicated repair procedure
  • Qualify the welders for the job if applicable
  • Remove the old lining
  • Inspect the C-steel vessel
  • Fit-up the new liners 
  • Weld the liners
  • Perform the final inspection (typically hydro test, visual, DPT, NH3 test, and gap checks)

Before installing new lining, Stamicarbon always removes the old lining and performs a careful evaluation of the carbon-steel vessel. Inspection results will identify the areas of damage – typically in the top part of the reactor – and ensure that the new lining fits perfectly. 

The hemispherical head can be covered with either liner plates and/or welding overlay.


When planning a relining project, you need to consider the size and shape of the vessel, its condition, the layout of the leak detection system, and many other factors. All these can be addressed by writing a vessel-specific procedure in preparation for relining. 

Depending on the size of the vessel, partial relining can take 15-20 days and complete relining – three months. That’s why performing a thorough inspection of the plant is essential to have the relining completed during the next planned turnaround.

We can advise you on the planning and preparation for relining to ensure optimal equipment repair in terms of quality, timing, and plant downtime.

Relining is typically performed on reactors, but our experts can advise if your plant needs a relining job on another vessel in the high-pressure synthesis section. 

Gas tungsten arc welding (GTAW) of liner segments
Gas tungsten arc welding (GTAW) of liner segments

Stamicarbon has over 20 years of experience in relining projects and we can design different packages of relining services depending on your needs.

We work together with reputable equipment manufacturers to help advance your existing plant operations. 

Not sure what type of relining solution is best for your plant? Our experts will be happy to help. 


  • Stami Urea Advance Brochure