my station installed hrsg at 2 units of GE 9E. the problem we encountered is the load tunnel temperature and exhaust back pressure.

i've seen lube oil diminister emitted white smoke. we changed the filter but no changes.

 

So, if I understand your post correctly, problems with load tunnel temperature and exhaust back-pressure began after installation of HRSG on two machines.

Do both machines have the same problem?

Is the load tunnel temperature high when the unit is running or when it's shut down after it's been running?

What kind of problem are you experiencing with back pressure? Is the reading not stable? Is the reading coming from pressure transmitters or pressure switches?

Are the devices (transmitters, switches) mounted above the pressure taps in the exhaust duct work or below the pressure taps? (They should be mounted above the pressure taps so that any condensate, and there will be condensate!, will drain back to the exhaust duct.)

What do the pressure "sensors" look like in the exhaust duct? Usually, a flat, circular disk with a beveled edge and a very small diameter hole in the center of the disk is welded to a piece of pipe or tube that protrudes through the exhaust duct wall. These are usually called "pancake probes" (pancakes are flat and round; the faces of these probes are flat and round).

Placement of the probes is also critical. They should not be obstructed by any duct work or support steel upstream or downstream of the probe. They should not be directly downstream of the compressor bleed valve discharge pipes. And the faces of the probes are usually only about 8-12 cm out from the wall of the duct work. There should be more than one probe, usually two with one mounted on one side of the exhaust duct and the other mounted directly opposite on the other wall of the exhaust duct, and they should be tubed together to feed the transmitters/switches with a common line. There should be no low point in the tubing where condensate can collect, and again, the devices should be higher than the taps. (It's not convenient, but it's the only way it works correctly. If the devices (transmitters, switches) are mounted below the pressure taps in the duct work, then it's likely that there is condensate in the tubing, and it's not common for drains (manual drains!) to be installed to remove the condensate when the devices are mounted below the pressure taps.)

If the exhaust duct back-pressure is high using the current instrumentation, have you used other instrumentation to verify that it is actually high?

If the exhaust duct back pressure is too high for the turbine and it's causing performance degradation, you need to talk to the HRSG supplier.

As for the visible emissions from the L.O. Mist Eliminator, this problem has been covered previously on control.com. Please use the 'Search' feature of control.com to find the previous threads.

Are both machines having the same problem with the L.O. Mist Eliminator discharge, or just one machine? Did the problem begin after installation of the HRSG(s)? Specifically, when do you see the vapors at the discharge of the L.O. Mist Eliminator? At FSNL or at Base Load? Or somewhere in between?

But, you need to know that the L.O. Mist Eliminator, at least the ones I'm familiar with, require periodic maintenance and even replacement of the internal elements. Also, there is some adjustment which must be made, and to make the proper adjustment one usually needs to install a pressure gauge (mm of H2O) on the L.O. Tank to measure the vacuum drawn by the L.O. Mist Eliminator.

Please answer all the questions. When posting in the future, please tell us what you've done to try to troubleshoot and resolve the problem(s). It's also very helpful to understand when any problem began (such as after a maintenance outage, or after a unit trip from load, or after a severe dust storm or rain storm). Just to say you have problems is not very helpful to us in trying to help with your problems. The more information you can provide, the more thoughtful and constructive and concise the replies will usually be.