condition monitoring for steam turbines i
TRANSCRIPT
-
7/28/2019 Condition Monitoring for Steam Turbines I
1/38
Condition Monitoring for Steam Turbines
and
Sleeve Bearing Diagnostics and Failure Analysis
Presented by:
Timothy S. Irwin, P.E.
Senior Mechanical Engineer
M&B Engineered Solutions, Inc.
13 Aberdeen Way
Elgin, SC 29045
Email: [email protected]
17 February, 2006
mailto:[email protected]:[email protected] -
7/28/2019 Condition Monitoring for Steam Turbines I
2/38
Condition Monitoring for Steam Turbines and
Sleeve Bearing Diagnostics and Failure Analysis
Part I - Condition Monitoring for Steam Turbines
What is todays definition?
We want an early warning so that when the operating condition of the turbine
is changing, action can be taken to identify the failure mode. When the
failure mode is properly identified, proper corrective action can be planned or
taken to maintain or return the machine to reliable operation.
Part IISleeve Bearing Diagnostics and Failure Analysis
What is todays definition?
Improve our understanding of sleeve bearings and their failure modes so thatwe can improve our monitoring techniques and failure analysis. Improvement
in these areas will result in an improvement in the equipments performance
and reliability.
M&B ESI
Timothy S IrwinJanuary 2006
-
7/28/2019 Condition Monitoring for Steam Turbines I
3/38
Part I Condition Monitoring for Steam Turbines
To develop effective condition monitoring we need tounderstand a little about the machine.
What does a turbine actually do?
Steam comes in and goes out right?
The steam comes in under a certain set of
pressure, temperature, and flow conditions;
and goes out under another set of pressure
temperature and flow conditions.
The change in steam conditions occursbecause we are using some of the energy
in the steam to rotate the turbine rotor.
M&B ESI
Timothy S IrwinJanuary 2006
-
7/28/2019 Condition Monitoring for Steam Turbines I
4/38
Part I Condition Monitoring for Steam Turbines
Just for a quick view, here is a decent description of a steam flow
path in a multi-stage turbine:
Courtesy of Power MagazineM&B ESI
Timothy S IrwinJanuary 2006
-
7/28/2019 Condition Monitoring for Steam Turbines I
5/38
Part I Condition Monitoring for Steam Turbines
Here is one small mechanical drive turbine.
This one was actually used to drive a positive displacement oil pump.
M&B ESI
Timothy S IrwinJanuary 2006
-
7/28/2019 Condition Monitoring for Steam Turbines I
6/38
Part I Condition Monitoring for Steam Turbines
Here is another small drive turbine
This one is also used to drive a positive displacement oil pump. M&B ESI
Timothy S IrwinJanuary 2006
-
7/28/2019 Condition Monitoring for Steam Turbines I
7/38
Part I Condition Monitoring for Steam Turbines
Here is a small industrial power generation turbine.
Note the mechanical layout of this machine M&B ESITimothy S Irwin
January 2006
-
7/28/2019 Condition Monitoring for Steam Turbines I
8/38
Part I Condition Monitoring for Steam Turbines
Here is a big multi-casing utility class machine
Note that a lot of the mechanical details from the
smallest to the largest machines are very similar
Courtesy of Power Magazine
M&B ESI
Timothy S Irwin
January 2006
-
7/28/2019 Condition Monitoring for Steam Turbines I
9/38
Part I Condition Monitoring for Steam Turbines
What kind of monitoring can we do on a turbine?
Steam conditions and flow rate.
Vibration.
Lubricant/bearing conditions.
Rotor speed/load or power.
Auxiliary system operation.
Noise/Sound levels.
M&B ESI
Timothy S Irwin
January 2006
-
7/28/2019 Condition Monitoring for Steam Turbines I
10/38
Part I Condition Monitoring for Steam Turbines
What kind of failures typically occur to turbines?
Bearing failures from:
Loss of lubrication
Lubrication contamination
Excessive load
Overspeed protection
Blade failures:
Foreign object damage
Erosion
Fatigue
Valve failures:
Solid particle damage
Erosion
Fatigue
Steam seal failures:
Wear
Erosion
Corrosion
Governor/Regulation failure
Insulation failure
Coupling failures
Hydraulic system failureM&B ESI
Timothy S Irwin
January 2006
Alignment Changes
-
7/28/2019 Condition Monitoring for Steam Turbines I
11/38
Part I Condition Monitoring for Steam Turbines
Lets look a little closer at some of the failure
modes. Bearing failures can occur from:
Loss of lubrication
Lubrication contamination
Excessive load
Electrolysis
Fatigue
Wear/wiping
Corrosion
Cavitation/erosion
Faulty assembly
M&B ESI
Timothy S Irwin
January 2006
-
7/28/2019 Condition Monitoring for Steam Turbines I
12/38
Part I Condition Monitoring for Steam Turbines
Lets look a little closer at some of the failure
modes. Blade failures:
Foreign object damage
Can cause damage to leading edge, trailing edge,
shroud, etc.
Can damage the stationary and/or rotating blades. Erosion
Can be caused by moisture in the steam or solid
particulates in the steam.
Can affect the stationary and rotating blades. Fatigue
Will more typically affect the rotating components and
typically be a catastrophic event if the condition is not
identified during an inspection. M&B ESITimothy S Irwin
January 2006
-
7/28/2019 Condition Monitoring for Steam Turbines I
13/38
Part I Condition Monitoring for Steam Turbines
Machine Condition Discussion:
Called in to evaluate condition of machine. Site management knew that routine maintenance had
been deferred for a significant amount of time.
Could they defer further or were there indications of
developing problems?
What were the results of the condition assessment?
Vibration levels were good (below 0.7 mils) using proximity
probes.
Power output was down.
Steam discharge conditions were at saturated steamconditions.
Steam leakage at shaft seals was excessive, causing constant
moisture contamination in the lube oil system.
My recommendation was not to defer the overhaul.
M&B ESI
Timothy S Irwin
January 2006
-
7/28/2019 Condition Monitoring for Steam Turbines I
14/38
Part I Condition Monitoring for Steam Turbines
Blade failure/damage:
M&B ESI
Timothy S Irwin
January 2006
-
7/28/2019 Condition Monitoring for Steam Turbines I
15/38
Part I Condition Monitoring for Steam Turbines
Blade failure/damage:
M&B ESI
Timothy S Irwin
January 2006
-
7/28/2019 Condition Monitoring for Steam Turbines I
16/38
Part I Condition Monitoring for Steam Turbines
Blade failure/damage:
M&B ESI
Timothy S Irwin
January 2006
-
7/28/2019 Condition Monitoring for Steam Turbines I
17/38
Part I Condition Monitoring for Steam Turbines
Valve failures: What happens to valves?
Erosion of the plug
Erosion of the seat
The steam admission valve or stop valve or emergencystop valve is part of the equipment protection!
Corrosion of the spindle or stem
Galling of the spindle or stem in the guide bushings or bearings.
Wear of the guide bushings or bearings
Wear of the linkage components
M&B ESI
Timothy S Irwin
January 2006
-
7/28/2019 Condition Monitoring for Steam Turbines I
18/38
Part I Condition Monitoring for Steam Turbines
Steam Seal failures: What happens to steam seals?
Larger machines with actual seal strips (labyrinth seals)
Wear of the seal tip height
Corrosion of the mating surfaces
Corrosion of the segments and housing.
Corrosion and failure of segment springs
Smaller machines with carbon seal rings
Wear of the carbon rings
Wear of the shaft surface
Corrosion and wear of the housing faces.
M&B ESI
Timothy S Irwin
January 2006
-
7/28/2019 Condition Monitoring for Steam Turbines I
19/38
Part I Condition Monitoring for Steam Turbines
Steam Seal failures: What happens to steam
seals?
M&B ESI
Timothy S Irwin
January 2006
-
7/28/2019 Condition Monitoring for Steam Turbines I
20/38
Part I Condition Monitoring for Steam Turbines
Steam Seal failures: What happens to steam
seals?
M&B ESI
Timothy S Irwin
January 2006
-
7/28/2019 Condition Monitoring for Steam Turbines I
21/38
Part I Condition Monitoring for Steam Turbines
Alignment
M&B ESI
Timothy S Irwin
January 2006
DefinitionWhat does alignment mean to coupled rotating machines?
In short we are looking for the two (or more) shaft centerlines to be
concentric to each other. If the shaft centerlines are not concentric
to each other, then the shafts through the coupling try to force themselves
together. Depending on the coupling type, this aligning force may show
Itself as various vibration signature changes or indications, or if severe
enough bearing temperatures or conditions may be affected.
What can cause misalignment?
Misalignment at installation or refurbishment
Thermal growth changes
Piping strain
Sleeve bearing damage
-
7/28/2019 Condition Monitoring for Steam Turbines I
22/38
Part I Condition Monitoring for Steam Turbines
Alignment
M&B ESI
Timothy S Irwin
January 2006
Definition What does alignment internal to a single machine mean?
In short We want to have the shaft/rotor within a certain position
relative to the casing. Some machines behave better with the rotor not
centered in the casing. Some machines behave better with the rotor
centered. A very typical indication is a rub condition in the vibration data.
What can cause misalignment?
Misalignment at installation or refurbishment Thermal growth changes
Piping strain
Sleeve bearing damage
Basically the same conditions apply to internal and external misalignment.
-
7/28/2019 Condition Monitoring for Steam Turbines I
23/38
Part I Condition Monitoring for Steam Turbines
Overspeed protection Sticking bolt
Worn linkage
Incorrect electronic settings
Governor/Regulationfailure
Worn parts
Contaminated system
Insulation failure Air gaps
It has become wet
Pieces are missing
Incorrect installation Coupling failures
Lubrication failure
Wear
Fatigue
Hydraulic system failure
Worn components
Contaminated system
Remaining failure modes:
M&B ESI
Timothy S Irwin
January 2006
-
7/28/2019 Condition Monitoring for Steam Turbines I
24/38
Part I Condition Monitoring for Steam Turbines
Failure modes and monitoring methods:
Realistically determine the most appropriate uses of the available tools.
We have to perform the following:
Determine the realistic limits of the monitoring tools.
Determine what we cannot measure or monitor.
Determine what is appropriate per piece of equipment.
M&B ESI
Timothy S Irwin
January 2006
-
7/28/2019 Condition Monitoring for Steam Turbines I
25/38
Part I Condition Monitoring for Steam Turbines
What kind of monitoring can we do on a turbine?
Steam conditions and flow rate.
Vibration.
Lubricant/lubrication conditions.
Rotor speed/load or power.
Auxiliary system operation.
Noise/Sound levels.
M&B ESI
Timothy S Irwin
January 2006
-
7/28/2019 Condition Monitoring for Steam Turbines I
26/38
Part I Condition Monitoring for Steam Turbines
Steam Conditions What kind of readings do we want to take?
Depends on the machine, what kind of readings do we haveavailable or can we take?
Is it a small machine with little instrumentation or is it a large
machine with a considerable amount of instrumentation?
Minimal measurements would be temperature and pressure
upstream and downstream of the turbine.
If you can include flow, power, inlet chamber pressure you will
know a considerable amount about the power characteristics of the
turbine.
Look for: A change in downstream conditions from what is normal.
It could be an increase in downstream pressure
Also understand what the design conditions may mean
(i.e. get a copy of some steam tables) M&B ESITimothy S Irwin
January 2006
-
7/28/2019 Condition Monitoring for Steam Turbines I
27/38
Part I Condition Monitoring for Steam Turbines
Steam Tables
M&B ESI
Timothy S Irwin
January 2006
Mechanical
Engineering
Reference
Manual
Michael R.
Lindeburg
-
7/28/2019 Condition Monitoring for Steam Turbines I
28/38
Part I Condition Monitoring for Steam Turbines
Vibration What kind of readings do we want to take? Depends
on the machine.If it is a small machine
Is it a sleeve bearing, anti-friction bearing, or combination machine?
Mag-based accelerometers are going to be severely limited with
sleeve bearing machines. But smaller horsepower machines are not
going to typically have proximity probes installed unless the machine
is very critical to the process.
What kind of data are we going to see on sleeve bearing machines
using mag-based accelerometers?
M&B ESI
Timothy S Irwin
January 2006
-
7/28/2019 Condition Monitoring for Steam Turbines I
29/38
Part I Condition Monitoring for Steam Turbines
PdM Routes
What data do I want?For vibration:
Horizontal and vertical on each bearing.
Locate the thrust bearing and take an axial reading.
Also include a speed reading if at all possible.
What are we looking for?
Vibration
Changes
Running speed multiples Increase in 1X
Increase in noise floor
Has the speed changed?
M&B ESI
Timothy S Irwin
January 2006
-
7/28/2019 Condition Monitoring for Steam Turbines I
30/38
Part I Condition Monitoring for Steam Turbines
For larger machines with installed shaft vibration
monitors:
Compare the shaft data to casing data.
How do those data sets compare?
Are they at different amplitude levels, but similar characteristics?
Are they different characteristics?
Multiples on the casing, not on the shaft data? Different noise floor levels?
Different phase indications?
Does the orbit shape generally agree with where you see higher
vibration levels on the casing?
Remember, we are looking for changes. Having absolute limits foroperation and equipment protection is one thing, but all the monitoring
instruments calculate vibration levels slightly differently. In the field, it
is hard to have an absolute anything.
M&B ESI
Timothy S Irwin
January 2006
-
7/28/2019 Condition Monitoring for Steam Turbines I
31/38
Part I Condition Monitoring for Steam Turbines
Lubrication /lubricant conditions
Again, what kind of machine do we have? Large or small? If it is big enough to have a sump, then we can perform typical
oil analysis testing.
Viscosity, water, particulates, and spectrographic for routine
Monitoring.
M&B ESI
Timothy S Irwin
January 2006
If it is not big enough for sump but uses oilers to ensure an oil supply
for the bearing housing there are still things that need to be correct for
a machine to achieve a reasonable time between repairs.
Oil level in the oiler.
Oil level in the bearing housing. Oil color in the oiler.
Inspect the housing cavity for typical indications of
contamination or condition during routine
overhauls.
-
7/28/2019 Condition Monitoring for Steam Turbines I
32/38
Part I Condition Monitoring for Steam Turbines
M&B ESI
Timothy S Irwin
January 2006
Lubrication /lubricant conditions
What are we looking for in an oil analysis?
There are three major condition groups that oil analysis can monitor:
Oil Condition
Viscosity
Additive packages
Oil Contamination
Moisture
Particulates
Equipment Condition Wear particles
Material or source
Ferrography
-
7/28/2019 Condition Monitoring for Steam Turbines I
33/38
Part I Condition Monitoring for Steam Turbines
M&B ESI
Timothy S Irwin
January 2006
Rotor speed/load or power.
Is there any permanent monitoring available?
Load
Speed
If no permanent monitoring is available, is there anythingelse you can use to verify operating load?
Is a place on the shaft available for an optical or laser tachometer?
Is the process controlled by inlet or discharge valves?
Are there any flow indications?
These items become even more critical for a variable load process!
-
7/28/2019 Condition Monitoring for Steam Turbines I
34/38
Part I Condition Monitoring for Steam Turbines
M&B ESI
Timothy S Irwin
January 2006
Auxiliary System Operation.
On larger machines, there are considerable auxiliary systems
that may also indicate development of a significant issue.
Gland steam or Seal steam systems
Shaft leakage increased
More use of steam Changing pressure conditions
Hydrogen seal oil systems
Higher flow rates from increased shaft leakage
Hydrogen purity issues
Changing pressure conditions Cooling water conditions
Conductivity
Flow or pressure changes
-
7/28/2019 Condition Monitoring for Steam Turbines I
35/38
Part I Condition Monitoring for Steam Turbines
M&B ESI
Timothy S Irwin
January 2006
Auxiliary System Operation.
On larger machines, there are considerable auxiliary systems
that may also indicate development of a significant issue.
Condenser conditions
Vacuum pressure changes
Condensate temperature changes Air in-leakage changes
Feedwater Heater conditions
Steam inlet/outlet condition changes
Condensate inlet/outlet condition changes
-
7/28/2019 Condition Monitoring for Steam Turbines I
36/38
Part I Condition Monitoring for Steam Turbines
M&B ESI
Timothy S Irwin
January 2006
Noise/Sound levels.
With modern ultrasound technologies, it should be possible to
monitor and trend changing conditions within these machines.
We should be able to monitor the following:
Valve conditions at known positions, especially when closed
Turbine noise levels at known conditions
Bearing noise levels at known conditions
-
7/28/2019 Condition Monitoring for Steam Turbines I
37/38
Part I Condition Monitoring for Steam Turbines
M&B ESI
Timothy S Irwin
January 2006
Summary
There are considerable technologies that are available for use
However, the tools we have discussed today are only several
pieces of an overall reliability program.
Preventive, Predictive, and Proactive or Reliability Centeredcomponents are all necessary to improve reliability and
minimize overall operational cost.
Basically, the more we know about the machine, the better we can
diagnose a changing condition.
-
7/28/2019 Condition Monitoring for Steam Turbines I
38/38
Part I Condition Monitoring for Steam Turbines
M&B ESI
Timothy S Irwin
January 2006
THE END
ANY QUESTIONS?