Dirt... and Fuel Gas
As background, one critical system in a power plant is fuel gas. Typically, every system is cleaned to a condition that is nearly spotless. This is especially true of fuel gas because it feeds the turbines and duct burners. EPR evaluated a plant that was physically very large. The fuel gas header was 1.5+ miles long, inside the plant downstream of the supplier custody-filters. The system changed elevations, had countless fittings, and pipe size changes. Clearly, this is a difficult system configuration to clean well for an inexperienced crew.
Prior to EPR being involved, roughly 50 warranty claims were raised against the EPC contractor that enumerated roughly 300+ failures of valves, flame scanners, regulators, and really anything in the system with a seat or rubber O-ring. The EPC contractor refused to address the issue on-the-whole with a proper RCA (root-cause analysis), instead dealing with each item as if unrelated.
The attached photographs tell the story. This system is so full of dirt and contamination that it's not defensible to indicate proper, or perhaps any, commissioning... Read more
No Savings. Contractor went through "motions" of cleaning system, just didn't!
Just in terms of Owner down-time for needless repairs this is millions of $'s. Parts, labor, etc...
At a plant in the Middle East, the EPC contractor failed to appreciate the difficulty and consequences of not properly cleaning the LP Steam distribution system and Condensate system during commissioning.
The plant was a very large combined-cycle plant with back-pressure steam turbines that fed a 72" header. That LP header in-turn fed a billion dollars in desalination equipment. This steam network was huge. Also given it's size, it would have been difficult in certain locations to get a sufficient steam velocity to remove scale and debris. It is doubtful, given the evidence of fouling in the system, that anyone tried very hard to achieve a degree of cleanliness.
One snapshot of the damage in the system is the return condensate pump impeller indications. These impellers are supposed to have a straight (square) leading edge. Keeping in mind, these pumps were only a year old, this is not normal wear. Also, condensate is supposed to be very clean with no debris...
A borescope was used to inspect the impellers in situ during a strainer cleaning. Debris in the strainers is evident... Read more
Maybe some schedule time.
Impeller replacement. Probably $250k +/- depending on number of times. 54 units.