Session: CS-06-01 The Martin Prager Memorial Session on API 579/ASME Code Fitness-for-Service Activities

Paper Number: 123511

123511 - Review of Shock Chilling Criteria in Api 579-1/asme Ffs-1 

Shock chilling can occur when a liquid or two-phase fluid comes into sudden contact with a warmer metal surface.  Within operating facilities, there are multiple applications which warrant consideration, including pressure relief systems and equipment startup in light hydrocarbon services.  The current screening criteria in API 579-1/ASME FFS-1 (2021) is based on an 8 ksi (55.2 MPa) limit for the maximum thermal stress occurring on the metal surface.  In this study, an analytical method was utilized to determine transient temperature, stress, and crack-driving force profiles through the wall thickness for different cylinder geometries using postulated flaw sizes.  Analytical results were compared against finite element models and show good agreement.  Discussion is provided regarding the margin associated with the current API 579-1/ASME FFS-1 approach.

Example problem 3.10 of API 579-2/ASME FFS-2 (2009) (which involves assessment of a demethanizer tower in the cold end of an ethylene plant) is revisited using the updated calculation methodology.

Recommended updates to the assessment procedures in API 579-1/ASME FFS-1 are provided.

Although not included in the recommended updates, quantification of constraint effects is shown using the calculation methodology in WRC Bulletin 590 for arbitrary through-wall stress distributions; arbitrary stress distribution are not currently covered in Annex 9I but are expected to be added in future editions.

Presenting Author: Clifford Hay ExxonMobil Technology and Engineering Company

Presenting Author Biography: Mr. Cliff Hay has over 25 years of experience in static equipment in the petrochemical industry. He was a Design Engineer for Ohmstede for 7 years and a Lead Mechanical Engineer at the ExxonMobil Baton Rouge Refinery for 12 years. He is currently the Principal Engineer for Advanced Analysis and Fitness for Service for ExxonMobil Technology and Engineering Company, a position which he has held for the past 5 years. He is also a voting member of the API/ASME Fitness for Service Joint Committee.

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