Our site Gas turbine under going commissioning. Just in beginning most of mentioned check valve were found passing.

oil was found from fuel oil purge air manifold. Also fuel oil mixing in water injection manifold. What could be the reason of this bulk failure

 

Proper flushing of these systems is critical to ensuring that no foreign material/debris can make their way into the check valves during initial operation.

 

All system were treated as per procedure.
matter is that why all check valve were failed together

 

When it comes to commissioning GE-design heavy duty gas turbines, there is procedure and there is on-site dictation of procedure.

In the procedure, it may or may not call for flushing; some don't these days; they presume all the pipe is properly treated and installed in a clean and protected manner or that field-installed piping is flushed before it is installed. Real-world conditions are another thing altogether. How long was the flange left open to atmosphere, and what are the ambient conditions are the site? What could have blown into the open flange connection(s) while field-installed piping was being fitted and installed?

On-site dictation of procedure usually involves lots of political, monetary and expedient decisions. And when politics, money and expediency get mixed together during a gas turbine installation, anything can (and does!) happen. From a cursory flush of one or two systems, to no flush at all, to something less than an ideal flush of all systems without allowing sufficient time for flushing or installing proper flushing equipment (hoses; valves; fittings; etc.).

So, when you say "procedures" were followed, what procedures? The OEM procedures? Site procedures? Procedures developed on site with the full and complete knowledge of how the piping systems were assembled (cleanliness; craftsmanship)?

We don't have any way of determining what procedures were used, nor how they were arrived at, nor how they were performed. Flushing is something that most everyone will agree is necessary, but almost no one plans for and no one (least of all the people with the purse strings and those trying to recover lost time and reduce labor costs) commits to executing properly with the full and complete knowledge of site construction conditions.

Your other post wasn't originally clear about the unit being in commissioning. Another cause for carbon deposits in piping could be the anti-rust preservative ("pickling") used in lots of pipe these days wasn't properly flushed out prior to running the turbine if this is a new unit start-up.

Still, the primary cause of check valve failure, whether en masse or one at a time, is debris or foreign material not allowing the check valve to close. And the primary cause of multiple check valve failure during initial operation is poor or non-existent flushing of field installed piping.

 

Dear
Thanks a lot for your explanation
I was thinking that may be some other factor also involve in check valve failure like,fuel oil quality,or some operating parameters as temp,press,etc.

 

DEAR CSA

I HAVE A QUESTION ON THE ARRANGEMENT OF TURBINE

USUALLY AT FIRST LOCATE COMPRESSOR THEN TURBINE ,THEN POWER TURBINE AND GEARBOX AND THEN GENERATOR OR PUMP WILL SET .

MAY BE ARRANGEMENT OTHER WAY MEAN FIRST GEARBOX LOCATED FIRST OF COMPRESSOR LIKE

PUMP OR GENERATOR THEN GEARBOX THEN COMPRESSOR THEN TURBINE ,POWER TURBINE .

 

JKH,

The location of devices and equipment is the purview of the manufacturer. A lot of manufacturers put the driven device (typically a generator) on the exhaust end. This causes some difficulties with sealing the exhaust, which means money and extra expense.

So, some units are built with the driven device on the axial compressor end of the machine, called the "cold end."

Again, the arrangement can be a function of many things, but mostly the manufacturer's design. Sometimes the application requires a different arrangement for one reason or another and if the manufacturer can accommodate the change, they will (for a fee, of course!).

Remember: A turbine is just a device for producing torque. Where the torque comes from (the exhaust end of the shaft or the axial compressor end of the shaft) doesn't make a difference. The torque needs to get transmitted to the driven device; that's all.

By the way, it's easier to read questions that aren't typed in all capital letters (at least for me).

And, it's a good idea to open a new thread for a new topic, since equipment arrangement isn't remotely related to check valve failures.