Session: OAC-06-02 Continued Safe Operation of Existing Assets-2

Paper Number: 123385

123385 - Recent Dynamic Events in Modern Large Gt-Cc Plants – Case Studies, Findings & Corrective Actions 

The paper presents the findings of investigative studies conducted for various transient incidents commonly known to occur in modern large combined cycle gas turbine (CCGT) plants. The damage from transient events can range in severity. Plant personnel can effectively address minor insulation damage and pipe deflections without extraneous efforts. More critical reactions, however, such as piping vibrations, damaged supports, and weld failures, can directly impact plant operability and may result in forced plant outages. High-energy piping systems become more susceptible to damage when transient events such as steam/water hammer or slug flow occur in combination with improper drainage. The locations known to be at risk are the Reheat (RH) and High-Pressure (HP) bypass valve outlets, where the condensate source is an attemperator. Inoperable or frozen drain legs, relief valves closed shut incorrectly during start-ups, etc., are other commonly seen sources.

The case studies detailed in this paper explore the correlation of condensate build-up in piping and the resultant dynamic loads. The case studies also closely examine the difference between using restraints and hydraulic snubbers to mitigate dynamic loads. Case study findings shed light on the importance of following proper drainage protocols during start-ups and shutdowns and the benefits of investing in the most optimal protection against transients. 

Presenting Author: Barrie Mollitor Tetra Engineering

Presenting Author Biography: BARRIE MOLLITOR
Tetra Engineering Group, Inc.
110 Hopmeadow Street  Suite 800  Weatogue, CT 06089 USA  Phone: 860.651.4622 Fax: 860.651.5524  www.tetra-eng.com

SENIOR CONSULTING ENGINEER OF MECHANICAL INTEGRITY

Versatile Stress Analysis Engineer with a demonstrated history of strong technical acumen, contract execution, and leadership in the power boiler industry. Skills include in-depth OEM power boiler knowledge (Foster Wheeler, Alstom, GE), pipe stress analysis, process design, FEA, creep and fatigue analysis, API-579 Fitness for Service analysis, and power plant field inspection.

Authors:

Anita Johny Tetra Engineering
Barrie Mollitor Tetra Engineering
Peter Jackson Tetra Engineering