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Tuesday, March 24, 2009: 2:00 PM
C304 (Georgia World Congress Center)
Standard and Vanadium enhanced 2.25Cr1Mo plate steels (ASTM A387 gr. 22 and A542 type D) are commonly used in refining plants for the building of heavy reactors.
These reactors are made of heavy plates or forged shells (thicknesses up to 300-350mm) and are submitted to thermal cycles (stop and go) and to strong service conditions (high pressure, hydrogen rich environment …). The main matter for end-user concerns the definition of Minimum Pressurizing Temperature (MPT). This temperature is the lowest temperature for which pressure can be put back in the vessel after shutdown. This minimum temperature insures no risk of brittle failure and is defined by fracture mechanics and CVN approaches and calculation.
This paper presents the methodology of MPT determination and the impact of ageing and hydrogen environment on material properties and then on MPT values. The method is explained in the case of a virtual but representative pressure vessel.
These reactors are made of heavy plates or forged shells (thicknesses up to 300-350mm) and are submitted to thermal cycles (stop and go) and to strong service conditions (high pressure, hydrogen rich environment …). The main matter for end-user concerns the definition of Minimum Pressurizing Temperature (MPT). This temperature is the lowest temperature for which pressure can be put back in the vessel after shutdown. This minimum temperature insures no risk of brittle failure and is defined by fracture mechanics and CVN approaches and calculation.
This paper presents the methodology of MPT determination and the impact of ageing and hydrogen environment on material properties and then on MPT values. The method is explained in the case of a virtual but representative pressure vessel.