CUI Major Incident# 11: Yara Ammonia Plant Explosion

cui incidents Sep 14, 2020

Date and Place of Incident:

On 27 June, 2009, an explosion occurred at Yara-owned fertilizer plant in Tertre, Belgium

Summary of the Incident:

The gas fire was occurred in the high-pressure synthesis loop because of the ruptured bypass pipe. The process unit was the ammonia synthesis high-pressure loop at 230bar. The ruptured bypass pipe on the gas feed piping to the start up heater caught fire involving the two adjacent boiler feed water (BFW) preheaters E501A/B.

Root Cause:

  • The rupture was occurred by the severe wall thinning of the pipe because of the corrosion under
  • The ruptured pipe was insulated but not in working. The main pipe was continuously kept in warm conditions. The small bypass over the manual valve was cold (approx. 80⁰C).
  • This temperature variance combined with the damaged insulation and water ingress possibilities was lead to CUI and cause rupture.

Environmental Impact of the Incident:

No environmental reported in the incident.

Fatality and injury:

2 minor injuries and no fatalities were reported in the incident.

Financial loss to Freedom Industry:

The plant shut down for 12 months which affect the production with the annual capacity of 420,000 tonnes of ammonia and 920,000 tonnes of nitrate,

Non-Compliance of Safety Guidelines and Reliability Practices:

  • The insulation of pipe was made by the poor quality material with water ingress
  • This pipeline was inspected partially in 2004; however, this affected section close to the supporting systems was not inspected.
  • The combination of quality and integrity of insulation and coating was the main cause of incident.

Recommendations to Avoid Corrosion:

  • Use of vapor retarders is a good defense method to avoid such incidents.
  • Painting and coatings prevent water contact with critical equipment. These materials provide good metal surface preparation and prevent the corrosion under insulation.
  • Proper Insulation shall be applied to prevent water ingress. Type of insulation has major role in these conditions

Links to the photos/videos:





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