Gas Turbine

[Wolskis]

Bucket guy taking inventory of the third stage buckets.

 

[Wolskis]

He lays a drop of RTV in the red marked areas and drops in the pin. This is enough to hold the buckets in place.

 

[Wolskis]

Moment weigh chart. 1st column is position on the wheel (shaft) which has 92 positions. 2nd column is the bucket number assigned to the wheel position. Moment weight is the last column.

 

[Wolskis]

This pipe guides LP (low pressure steam 80psi) into the steam turbine. It's 20" diameter and about 40' long. The other end has the LP stop valve which was unbolted to inspect the valve. Night shift was instructed to remove the LP control valve. They were down to 3 or 4 bolts and the pipe dropped several inches. Walking down the pipe we noticed a lack of a pipe hanger. That was confirmed by the isometric drawing. Here wire ropes and come alongs used to get the pipe back into position.

 

[Wolskis]

Transition pieces. The holes are for cooling. The rectangle is called the picture window. Yellow is the coating. BTW these parts look fantastic for having been fired for 26k hours.

 

[Wolskis]

#1 nozzles, easily distinguishable by the coating and all the cooling holes.

 

[Wolskis]

#2 nozzle from the shaft. Has coating but reduced number of cooling holes as it's further down stream from the heat source.

 

[Wolskis]

And we have the last or 3rd stage nozzles. Notice the size increases also.

 

[Wolskis]

This joint is failing and the fix will have to wait for the 2022 budget period. About $80k. That's 900 degrees of engine exhaust temp damage.

I'm finding out others are seeing the same issue.

 

[Wolskis]

1st stage buckets

 

[Wolskis]

Last stage steam turbine blades or called L-0. Hope to get closer this afternoon. The entrance is yellow tagged. I need fall protection on.

 

[spectra3279]

So does this drive a gear box or only make heat?

Sent from my SM-G973U using Tapatalk

 

[Wolskis]

In the process of de-blading. Rotating the shaft to bring the 1st stage blades with in reach

 

[Wolskis]

The ability to jack over the shaft relies on the lift oil pump. The shaft has 4 journal bearings, one on each end of the generator and gas turbine. At the bottom of each bearing has a small hole for high pressure (2,000 psig) oil that lifts the shaft. With out that oil this action could happen.

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[Wolskis]

De-blading stage 1. Jacking over the shaft to bring the the next set of blades for removal. 92 times. The tip of the air hammer is nickle. At the end he is removing a pin that keeps the blade in place. He will continue this in 100% rain tomorrow for stages 2 & 3 with a cover. GE is on a schedule, they have 18 days for this event called a HGP or Hot Gas Path. Happens after 28,000 operating hours.

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[Wolskis]

So does this drive a gear box or only make heat?

Sent from my SM-G973U using Tapatalk

The exhaust temperature of the gas turbine is about 1050 degrees F. Connected to the gas turbine is what is known as the HRSG or Heat Recovery Steam Generator or simply a water boiler.
So the first set of tubes is the HPSH or high pressure superheated steam. Two forms of steam, saturated or superheated in the HRSG world. You guys can explore that.
At the back end of HRSG the exit temperature has been reduced to 200 degrees F. So from front to back are rows of tubes containing pure water that absorbs the heat.
The water gets to the boiling point and changes states from a liquid to a gas or steam. Just like on the stove, that pot of water gets to a boiling point and you've created saturated steam.

This steam is directed thru piping to the steam turbine. It sucks the energy out of the steam in a series of more blading that rotates the shaft and is connected to a generator to light your house. That steam is then returned to a liquid state under a vacuum. That water is than pumped back in to the HRSG and the cycle repeats itself. This is called combined cycle
See, ezzzz pezzzzeee

 

[Wolskis]

Let's inspect the ST exhaust trunk.

 

[Wolskis]

Get the fall protection on and let's go.

 

[Wolskis]

We'll walk the trunk and come back to the steam turbine. Can you see the end?

 

[spectra3279]

The exhaust temperature of the gas turbine is about 1050 degrees F. Connected to the gas turbine is what is known as the HRSG or Heat Recovery Steam Generator or simply a water boiler.
So the first set of tubes is the HPSH or high pressure superheated steam. Two forms of steam, saturated or superheated in the HRSG world. You guys can explore that.
At the back end of HRSG the exit temperature has been reduced to 200 degrees F. So from front to back are rows of tubes containing pure water that absorbs the heat.
The water gets to the boiling point and changes states from a liquid to a gas or steam. Just like on the stove, that pot of water gets to a boiling point and you've created saturated steam.

This steam is directed thru piping to the steam turbine. It sucks the energy out of the steam in a series of more blading that rotates the shaft and is connected to a generator to light your house. That steam is then returned to a liquid state under a vacuum. That water is than pumped back in to the HRSG and the cycle repeats itself. This is called combined cycle
See, ezzzz pezzzzeee

I don't know but seems a flame and boiler would be cheaper.

Sent from my SM-G973U using Tapatalk

 

[Wolskis]

When the plant is in a start up phase and before steam can be admitted to the ST it must be super heated or lacking of water. If not, wet steam can cause severe damage. Water in steam traveling at a high rate of speed and contacting metal can make pipes jump. It's sometimes called water hammer. It's not pretty.
The steam is in a bypass mode, meaning it gets piped directly to the condenser. You are looking at the HRH (hot reheat) and LP (low pressure) entries to the condenser. Fifty feet in front of these, water gets injected into the steam via spray nozzles to reduce the steam temperature.

 

[Wolskis]

This is called the drain pot. By this point in the trunk water has fallen out ot the steam and

collects in here which than gets pumped back into the system. It's not much.

 

[Wolskis]

This is the street 1 riser. I'm looking for any damage, cracked welds, pieces of something laying on bottom of the trunk and erosion.

 

[Wolskis]

Continue on down. This has been around since construction. Just something to monitor

 

[Wolskis]

These get a little more eroded each time. The white is getting into the base metal. Again something to monitor. I don't ever see this getting to a point of failure.

 

[Wolskis]

Now at the end. Turning vanes.

 

[Wolskis]

Open hatch at the end. Let's head back.

 

[Wolskis]

Here are the rupture disc's from post 38 but from the inside.

 

[Wolskis]

Two heavy pieces of metal under a heat load cannot be mechanically connected, they must have an expansion joint. This joint is protected by a heat shield.

 

[Wolskis]

Here we are at the last stage of the LP (low pressure) turbine. Referenced as the L-0 blades. The next stage up is the L-1 stage and so on.
Inside the white circles are the hood spray nozzles. When first admitting steam the flow is not high enough to push the steam along. At these low flows the steam is stagnant and can absorb more heat. The nozzles come into play at this point. Water is injected to absorb the heat. But this becomes pointless if steam flow does not incresse. Another factor is water droplets coming into contact with the rotating blades causing erosion. I witnessed this at my last plant. Over time this happened creating micro cracks in the L-0 blading. A blade broke off and the repair lasted 6 months. The collateral damage was significant.
I eyeball the blades once a year.

 

[Wolskis]

The L-0 blades are locked together at the ends.

 

[Wolskis]

These are the snubbers, at the mid point keeping the blades from flexing.

 

[Wolskis]

Outside view of the expansion joint.

 

[Wolskis]

Last post for tonight.
Emerson is calibrating our coriolis natural gas fuel meters. Something we are required to do every 5 years per our air permit. We are the first. Previously the meter was sent out for this calibration. To do that you must have a spare. Good for us, we saved $70k.

 

[Wolskis]

Ok this is the last post. I spend 4 months planing and coordinating each outage. From cranes to gaskets, dumpsters to filters, inspectors to boilermakers. Each day brings new challenges. Each employee is tasked with something and in the end the plant comes back together and we run for another 6 months. Rinse & repeat.

 

[mash on it]

Quite fascinating.
Well above my pay grade.

Dan'l

 

[Wolskis]

Craft rtv'n seal stripes into the shroud blocks

 

[Racer56]

Love this thread! Keep up the great work!

 

[Wolskis]

Glade your enjoying this. We push the start button on this machine early morning of the 29th. Mechanical completion is the 26th. The plant is than responsible for reconnecting instruments and electrical. Plus insulation. Then the operators have to check alignment of all systems.

 

[Wolskis]

I was stuck in the office most of the day chasing parts which was ok, it rained all day long.

 

[Wolskis]

Here's a pic of some of the steam piping.
HP = high pressure steam can reach 2300psig at 1050F.
HRH = hot reheat steam, 600psig at 1000F.
CRH = cold reheat steam, 600psig at 900F.
LP = low pressure steam, 80psig at 180F.

 

[Wolskis]

The steam pipe loops allow the pipes to move, grow and shrink with the heat.

 

[Wolskis]

Some of the parts I had to source,
This o-ring , 4 hours
This gasket came out of the natural gas pipe connected to the the coriolis meter from earlier. Two dissimilar metals needs an insulation flange kit, 6" dia at a system pressure of 300#.
I need by noon Friday so I ordered 4 kits each from 2 different sources. Coriolis meters need to be all bolted up by COB Friday. What I still lack is the torque value of the nuts an bolts. My fingers are crossed that number comes in the kit.

 

[Wolskis]

We did have a talented a crew of welders. They can be prima donna's but worth it.
The pics don't serve these welds justice. Now these are code welds. I don't have the staff for certified welders so I go with a GC. I supply any drawing we have of the effected areas and the material makeup. The GC reviews, follows welding standards, submits weld procedures, hires welders, completes the job, contacts the AI or authorized inspector. The GC has to convince the AI these welds meet all laws and standards. Paperwork is kept for life of the equipment.
My mechanic is a former welding QA inspector so he keeps us out of trouble.

 

[Racey]

So cool! Thanks so much for posting all of this!

 

[Wolskis]

Going back to post 71, you see HRH & LP steam bypass inside of the the condenser. Now from the outside.

 

[Wolskis]

More steam piping

 

[Wolskis]

I might have mentioned this earlier, I don't remember. Here we are having an outage in March. Outside in Ohio weather. Not by choice. These .05's are new machines. Spare parts really don't exist. Typically the parts removed are repaired and could end up in bum f no where. Because there aren't enough parts in the inventory, we had to alter by several months our outage dates. These parts will go thru refurbishment and end up back with us in November. The new parts going in are capital spares we purchased 4 years ago at 7.5 mil.

 

[Wolskis]

De-blading row 3 buckets contined thru the night. This was 0600 est.

 

[Wolskis]

1300 today, de-blading continues. We think they might be 1 shift behind.