Tetra has published a series of guides which are available for ordering.
A selection of technical papers available for reference.
Selected papers, presentations and articles from major industry conferences and events.
With over 30 years of experience in power and industrial steam generation services, Tetra Engineering has along history of projects.
Tetra Engineering completed a Tube Failure Analysis of failed SH tubes from a CCGT plant in South East Asia. The results show the following damage mechanisms present: Short-term Creep and Fatigue damage (Creep-Fatigue interaction) Short-term Creep and Stress Corrosion Cracking (SCC) or Hydrogen Embrittlement The fact that short-term creep damage was observed on both of the failed tubes indicates a sudden change in temperature. It was possible that newly discovered damage to the turbine exhaust flow correction device could have allowed a larger mass flow to one side of the boiler (due to swirl influence), increasing the tube temperatures locally and/or increasing local stresses when expansion is prevented, thus accelerating creep damage. The plant had suffered from frequent fatigue failures, with several independent metallurgical analyses over the years confirming thermal fatigue as the previous root cause. No signs of any creep damage had previously been discovered.
Tetra Engineering was asked to assess the situation after a significant water slug/hammer event. Observations made during the site visit showed that the structural members were severely damaged with steel being heavily deformed and torn in some cases. Piping supports were also severely damaged and would require repair.
Tetra Engineering was asked by a client to help to assess the cause of tube failures in the upper section of the LPEVAP on their HRSG units. The first tube failure was reported in 2010; other failures have followed since then at a rate of two to three per year. At the time of the first failure the plant had been operating for approximately three years. Tetra performed a root cause analysis which included a review of water chemistry logs, boiler simulations using PPSD as well as a FAC Risk Assessment.
A CCGT power plant employed Tetra to perform a review of possible boiler preservation options within the context of the present and planned operating regime. The review relied on information supplied by the plant staff, Tetra field experience and latest industry trends and practices to identify the most promising strategy for preservation. The ideal solution for this client was Dry Layup that is systematically applied when it reaches the end of the standby period. This would require that resulting startup timing meets requirements imposed by the governing network operator.
