You are currently viewing: Q&A

---

---

• It is well understood that the Mimium Pressurization Temperature is the temperature below which the steel is assumed to be brittle due to H2 Embrittlement in hydrotreating units. 

  How to understand conceptually, why beyond MPT value, H2 embrittlement is not an issue or reactor is not suspectible to loss of ductility, eventhough pressure after MPT value will be higher than before. Can someone please guide me? 

  Jun-2023

---

Answers

---

• Marcio Wagner da Silva, Petrobras, marciows@petrobras.com.br

  This is strictly related with the material behaviour. The Minimum Pressurization Temperature (MPT) or Minimum Safe Pressurization Temperature (MSPT) establishes the minimum temperature that the reactor material still present toughness to avoid internal tension which lead to a transition from a ductile to fragile behaviour, this is especially important in unplanned shutdown of the hydroprocessing units.

  Above the MPT, despite the higher pressure, the reactor material present adequate toughness to avoid internal tensions capable to produce failures due to the hydrogen embitterment. It's important to know the MPT envelop of the reactor material to define the limits of the reactor and decision making during operational emergencies. Normally, it's recommended that the maximum pressure applied to the reactor do not exceed 25 % of the design pressure below the MPT.

   

  Jun-2023