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.
In 2015, it was discovered that the thermal sleeve in the attemperator in a client’s power station hot reheat line had failed, resulting in fracture around the circumferential weld in the sleeve’s mid section. For this reason, Tetra was engaged by the owner to investigate. The investigation showed failure from fatigue cracking. There were no signs of thermal fatigue damage, hence quenching from over-spraying was discounted as the root cause. The cracked area showed signs of high cyclic local strain, and given the moderate number of starts low-cycle fatigue was thought to be the root cause. Differential thermal expansion between the Grade 22 sleeve and the Grade 91 pipe, combined with lock-in of the sleeve on the pin locations, would raise sufficiently high stresses
Tetra was engaged by a client to perform a finite element analysis of the HP Bypass valve reducer, using measured displacements as input. Results from a strain gauge/displacement survey showed a large strain effect occurring during the start-up of the boiler. Initially, both the left and right side strain gauges on the reducer showed compressive strain. During the start something triggered the reducer to experience tensile strain that differed in its intensity between left and right. The purpose of the study was to try to simulate the observed strain fields and determine the root cause.
A Tetra Senior Engineer visited a south east asian power plant site to make an assessment of the commissioning situation. The EPC engaged Tetra as they considered that their site work was being delayed due to lack of progress by the IPP to perform their scope of work.There was significant lack of communication between the two parties as well as discrepancies in the scope of work, which lead to schedule delays and cause of mutual blaming between parties.
Tetra was hired by a client to investgate the remaning life of the HEP on 3 units of a thermal power station. The plant intended to operate the units for another 100,000 hours. The scope of work entailed a piping stress analysis of the main steam and hot reheat lines, thermal stress analysis of the SH header outlet/main steam line and remaining life assessment (creep, fatigue, creep-fatigue) of critical areas based on inspection history and results from the pipe stress/finite element analysis. The figure shows time-dependent stresses and temperatures during start up.
