96BD-1 Process Line Clogged

We were having issues with Exhaust Mass Gas Flow. It was traced to 96BD-1 (Compressor Bellmouth Differential). The low side process line is clogged. We found about a pint of black water wash liquid in the tubing. It was drained at the low point of the tubing where it inserts at the bellmouth housing (turbine compartment side). Removing the liquid did not unclog the process line. There are six taps for the tubing. It encircles the bellmouth housing.

We have a GE frame 7FA combustion turbine. I have researched all drawings available to find out where the path of inlet flow enters the bellmouth and exits to the tubing taps. We entered the bellmouth area looking for the obvious. The IGVs were closed and we were on gear so our look was limited. Without knowing the path I am not confident to pressurize the taps to clear out the clog.

Any information on this matter is greatly appreciated!

Presuming a lot of details, I'll offer a speculative possibility

With any d/p flow measurement involving gases with a condensible component, you have to insure that the lines are sloped as to be self-draining either back into the process or though a collection pot with suitable drain. It may even be necessary to heat trace some process tubing.

Rod out or replace the tubing, taking care to handle the liquid buildup.

Good luck.

Upon further investigation we found that the holes were painted over after an outage. They are located in the bell mouth casing approx. 6" from the IGV's (entrance to bell mouth). They are six holes.

Thank you for the reply!

calgirl17,

Thank you very very much for the feedback! I was certain the penetrations were in the bellmouth casting, but could not have realized they would have been painted over.

Again--thanks for the information.