Criticality of High Speed Separable Alignment

7/30/2019 Criticality of High Speed Separable Alignment

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2003 Gas Machinery Conference 1

THE CRITICALITY OF HIGH-SPEED SEPARABLE ALIGNMENTby:

Randy R. Raymer (El Paso Corporation)

Robert Goodenough (El Paso Corporation)

Ralph E. Harris, Ph.D. (Southwest Research Institute

)Anthony J. Smalley, Ph.D. (Southwest Research Institute)

This paper will cover four distinct areas:

1. The evaluation of alignment on crankshaft-induced stress.

2. A discussion on why the high speeds are very different from the slow-speed

units.

3. The equations and evaluation processes required to properly achieving

satisfactory alignment.

4. A recommended procedure that can be used as an installation specification.

This discussion will show a case history of an actual installation and the reduced

crankshaft stress levels achieved through proper alignment techniques. The paper will

discuss the Finite Element Crankshaft model and show how distortion, stress, and bearing

reaction loads were evaluated. In addition, the paper will provide readers with a

specification adaptable to individual company usage, which will assure proper alignment

at the time of installation.

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1.0 Introduction

El Paso Corporations recent horsepower replacement project compressors

have now been running for approximately 2 years. This effort involved

installation of ten 8000 HP high speed Ariel units with both electric drive and

engine drive configurations. The fixed speed electric drive units incorporate

Hydrocom capacity control, the engine drive units utilize Wartsila engines with a

speed range of 575 to 750 rpm (figure 1). On the engine drive units, cylinder end

de-activation and conventional pockets are used in combination with speed

reduction to achieve turn down ratios of more than 50%. Installation of these

units involved several industry firsts with respect to throughput, drivers, speed

and capacity control. As described in (1), several vibration issues arose, and

have been managed to varying degrees. Many of these issues were associated

with fundamental design decisions, both acoustic and mechanical. Following

8000 hours of operation, alignment checks on all units were made. These

alignment reviews were made in a continuing effort to resolve elevated vibration

levels as well as unusual main bearing wear patterns. Significant misalignment

was found on several of the units, however, interpretation of the data with respect

to the role of alignment on vibration and unit integrity has been difficult to make.

This paper presents an overview of ongoing efforts to interpret the alignment

measurements, pre and post re-alignment vibration data, as well as a procedure

developed to ensure proper initial or re-alignment of machines of this class. In

addition, preliminary results of testing to acquire crankshaft dynamic strain will

be presented. The dynamic strain values are to be used in combination with finite

element models of the crankshaft and alignment data to establish meaningful

alignment criteria for the family of compressors.

2.0 Alignment Results and Analysis

Frame based measurements of relative height along both sides of the units

were obtained. Measurements on both the compressor, and driver (engine/motor)



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were acquired on all 10 installations. Of key interest is the bearing centerline

distortion. In order to establish bearing displacement data from frame

measurements, El Paso utilizes an Excel based alignment analysis package

(Alignment Master). This software incorporates the geometry of the machine,

and the location of the measurement points to establish absolute estimates of the

bearing centerline position, as well as the position of the bearing centerline

relative to a mean plane passing through 1 of the bearing locations. This mean

plane has the same average slope (parallel to crankshaft) and list (perpendicular to

crankshaft) as the compressor/driver. Figures 2 and 3 present the data from two

of the units tested. The compressor frames are relatively square in cross section,

and the distances from the frame edge to the bearing centerline is short in

comparison to much of the installed fleet of integral slow speed units. For this

reason, minor variations in frame misalignment translate into significant bearing

centerline distortion.

In order to help interpret the data, simplified finite element models of the

crankshaft were developed (see figure 4). These models use the geometry of the

crankshaft, and simplified spring representations for the bearing. Linear bearing

stiffness values of 10^7 lbs/inch are used at the main centerlines. Clearly more

complicated solid models of the crankshaft can be generated, however, for the

relative ranking of stress severity across the fleet of units it was felt that this

model would be sufficient. Bearing horizontal and vertical distortions (relative to

mean slope and list) were applied to the base of the bearing springs. Modeled in

this fashion, the static stresses throughout the crankshaft are estimated from

applied bearing misalignment. Since the orientation the crankshaft producing the

worst case stress cannot be pre-determined, the crankshafts are modeled and re-

run at 45-degree increments. Von Misses stress levels are used to compare the

relative severity of the misalignment for the ten units. The calculation of static

stresses represents an estimate for the running speed stress levels as the crank

rotates neglecting dynamic amplification effects. This is a reasonable assumption

if the bending modes of the crankshaft are sufficiently far removed from the



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operating speeds. Figure 5 presents the first bending mode of the crankshaft

calculated for the model. The resonant frequency is estimated to be 330 Hz.

Figure 6 presents the predicted crankshaft displacement for the bearing

distortion condition of figure 2. The corresponding stress levels associated with

misalignment throughout the crankshaft are seen in figure 7. Note the significant

slope change through the main bearing regions in the highly distorted regions.

This would suggest that distributing the bearing springs along the length of the

main bearings would be an improvement to the model. Figure 8 and 9 present

the corresponding results for the bearing centerline distortions of figure 3.

Clearly the relative displacement of adjacent main bearing is more important to

raising stress levels in the crankshaft than peak to peak differences along the

entire set of bearing.

Table 1 presents a summary of results for the ten units. Note that bearing

reaction loads computed from the resulting bearing centerline distortions are low

in comparison to applied gas forces based on rod load limits of 80,000 lbf.

Unusual bearing wear patterns have been observed in the main bearing of some of

the units, and this appears to correlate with the predicted change in displacement

across the main bearings using the FE model.

Based on the bearing centerline distortion data and the FE analysis, unit 2

at station 96 and unit 2 at station 47 were selected for re-alignment. A detailed

procedure developed by El Paso for the alignment of separable high-speed units is

provided as an attachment to this paper. Just prior to the re-alignment effort

vibration data was acquired on both units at full load operating conditions. Test

points included cylinder vibration in the stretch, vertical and horizontal directions,

frame vibration, and relative displacement between then frame and skid measured

using proximity probes. Figure 10 presents representative cylinder vibration

spectrum in the stretch and vertical directions. Note the relatively small

contribution at 1st

order to the overall frequency content out to 200 Hz. Figure 11



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presents the cylinder stretch and frame stretch response. Again note the low 1st

and 2nd order components. Figures 12 through 15 present the final alignment

conditions and stress predictions following re-alignment. Significant reductions

in both bearing centerline distortion, and predicted peak stress levels were

achieved. Vibration data was re-acquired on both units in the newly aligned

conditions. Every attempt was made to ensure similar test conditions with respect

to speed, torque and load step. Table 3 presents a summary of results. Vibration

and displacements before and after alignment were analyzed in the frequency

bands 0-65 Hz and 0-200 Hz. No consistent trend in the results can be found in

the results at station 96. Similar results were obtained at station 47.

3.0 Discussion

The results of the above described efforts raises serious questions

regarding; the need for alignment, the impact of alignment on vibration levels, as

well as alignment criteria on units of this type. The test data clearly establishes

that misalignment can not easily be detected from external vibration

measurements. Historically on low speed integral compressors, vibration levels

measured on the frame or foundation would reflect large changes in alignment.

For the unit discussed in this paper, the small contribution of the low orders (1st

and 2nd

) to the overall vibration levels are likely contributing to this result.

These units have shown themselves to be difficult to align, and appear to

shift alignment quickly despite best efforts to improve frame and skid bolt down

conditions. Establishment of reliable alignment criteria, (and perhaps less

stringent criteria) for these particular units would be desirable under these

conditions. The approach utilized here, specifically the use of FE models in

conjunction with alignment data is a possible path forward. However, as noted

earlier, more refined models of the crankshaft would be required. In an effort to

move in this direction, testing has been completed on an electric drive unit at

station 54 to acquire data to assist in the calibration of the stress models. Using

SwRIs Strain Data Capture (SDCM) technology, strain levels in the fillets of the



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main bearings have been acquired. The SDCMs are microprocessor-based

instruments, which power, condition and sample the strain data. The instruments

are programmed to acquire data at selectable intervals and store the data in non-

volatile memory. At the completion of the test, the units are removed and the data

is downloaded to a PC for analysis. Typically, data is acquired at intervals on the

order of 1 to 5 minutes. These devices have been used on a variety of compressor

types including a very large hyper unit used in LDPE production.

For the tests completed at station 54, data was acquired at 5-minute

intervals for 24 hours. The compressor had previously been shut down for a 3-

week period. Six SDCMs were installed along the crankshaft of the machine.

Five strain gages were located in the fillet of the crankshaft adjacent to the main

bearing. Three were installed on the compressor pin side of the main bearings

(Figure 16), two were installed opposite the compressor pin side. Due to the thrust

bearing at the drive end of the shaft, the final gage was installed on the inside of

the web (Figure 17). The state of alignment on this unit was recently determined

and both crankshaft distortion and predicted stress levels were similar to worst

case conditions presented earlier in this paper for the other units. Figure 18

presents station-recorded unit HP and Hydrocom setting for test effort. Figure 19

presents the overall cylinder and frame stretch vibration levels (5-200 Hz). Note

that the unit shut down 3 times during the test due to suction gas temperature

sensor problems. The strain levels recorded on the compressor pin side units are

presented in figure 20. There are several key points to note. The low HP strain

levels represent the majority of the full load levels. The low load levels consist of

inertia driven and alignment driven crankshaft loads. The gages were located at

the same depth in the fillet on the crankshaft, thereby minimizing location

differences between the strain data. The low load (immediately following startup)

levels are within 43 micro strain of each other. This is approximately a 1300-psi

difference in stress between the locations. The FE calculations for the crankshaft

predict peak stresses at the E gage location to be 4400 psi. At the A gage

location, peak stresses are predicted to be 400 psi. This is a difference of 4000 psi



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or approximately 130 ustrain, just over 3 times less than measured. However,

since gas and inertia loads are not include in the model, we cannot conclude that

the crankshaft is less sensitive to misalignment than the geometry of machine

would indicate. Clearly a reduction in effective bearing stiffness in the model

would reduce both the predicted stress levels in the crankshaft and the relative

differences across main bearings. Much more analysis of the SDCM data is

required, including spectral analysis of the strain data as Hydrocom values are

changed.

4.0 Summary

This paper outlines the effort to address the serious and challenging goal

of developing alignment criteria for the HP replacement compressors. The

measured crankshaft strain data indicates that the majority of the crankshaft stress

is due to inertia terms, with only minor increases associated with unit loading.

Peak stress levels do not appear to be sensitive to the state of misalignment. Use

of FE models in combination with crankshaft distortion data appears to provide a

systematic manner to access the significance of the alignment data. Continued

refinement of the analysis models should produce a reliable screening tool for the

compressors in question.

[1] Acoustic and mechanical dynamics issues for high horsepower, high-speed

compressors in gas transmission service. Presented 2002 GMRC Gas Machinery

Conference.



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Figure 1: HP replacement units

v 8,000 HP Siemens Motor DrivenUnit (720 RPM Fixed Speed

capacity controlHydroComs,unloaders >50%turndown)

v 8,000 HP Wartsila Engine DrivenUnit (575 to 750 RPM capacitycontrol pockets, variablespeed,>50% turndown)

Figure 2: Station 96 U2 Alignment Summary



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Figure 3: Station 63-U1 Alignment Summary

Figure 4: Basic Crankshaft FE Model

Vertical Bearing Stiffness (1e7 lbf/inch)

Horizontal Bearing Stiffness (1e7 lbf/inch)

Crankshaft Distortion data

Applied to base of bearing springs



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Figure 5: Frequency Analysis(1stbending mode)

Figure 6: Station 96-U2 Crankshaft Displacement



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Figure 7: Station 96-U2 Crankshaft Stress

Figure 8: Station 63-U1 Crankshaft Displacement



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Table 1: Summary of Response Predictions

96 U1 96 U2 87 U2 87 U1 47 U2 47 U1 54 U1 54 U2 63 U1 63 U2

maximum crankshaft distortion (mils) 9.6 11.9 4 6 5.3 6.9 1.8 7.4 9.2 14

maximum crankshaft stress (0-pk) 2709 6461 1110 3275 5329 2495 1018 3655 2181 3107

maximum reaction lo ad (lbs) 6178 15006 3626 6422 17859 4581 3141 7234 4044 3230

Maximum Mils across bearin g 1 1.4 0.9 1.3 1 1 1.5


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Figure 10: Typical Cylinder Response Spectra

Cylinder

Stretch

Cylinder

Vertical

Figure 11: Typical Cylinder/Frame Response Spectra

Cylinder

Stretch

Frame

stretch



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Figure 12:Station 96 2D Re-Alignment

Summary

Figure 13: Station 96-2D Crankshaft Stress



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Figure 14: Station 47 U2 Re-Alignment

Summary




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Table 2: Comparison of distortion and stress

levels following alignment

96 - D2 47 - U2 96 - D2 47 - U2

maximum crankshaft distortion (mils) 11.9 5.3 1.5 1.08

maximum crankshaft stress (0-pk) 6461 5329 726 1037

maximum reaction load (lbs) 15006 17859 2180 3187

Maximum Mils across bearing 1.4 1 0.9 0.7

Alignment AlignmentBefore After

Table 3: Comparison of vibration results following

Re-alignment (station 96)

location Ratio (before/after (5-65 Hz)) Ratio (before/after (5-200 Hz))c1 stretch 1.03 0.87

c2 stretch 1.08 0.87





locationc1 horizontal 0.92 1.08

c2 horizontal 0.86 1.15





locationc1 vertical 0.57 0.96

c2 vertical 1.43 1.22





location

c1 SB stretch 0.75 0.73c3 SB stretch 1.00 1.08

c5 SB stretch 0.79 0.76




locationc1 frame stretch 0.92 0.95

c3 frame stretch 1.42 1.52





location Ratio (before/after (5-65 Hz)) Ratio (before/after (5-200 Hz))c1 DB stretch 1.68 1.31

c3 DB stretch 0.84 1.03





locationskid C1 stretch 1.00 0.58

skid C1/C3 stretch 1.20 0.83


skid C5 stretch 1.00 1.33





locationframe C1 vertical 1.64 0.85

frame C2 vertical 1.21 0.93


frame C4 vertical 1.50 1.13frame C5 vertical 1.55 0.95


locationodd chock 1 0.58 0.10

odd chock 2 0.58 0.16

odd chock 3 0.25 0.04

odd chock 4 0.18 0.19

even chock 1 1.00 0.55






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Figure 16: SDCM unit installed on crankshaft

(main bearing fillet)

Strain gage on main fillet

SDCM mounted

on web flatCompressor Rod

Figure 17: SDCM unit installed on WEB

Strain gage on

web



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Figure 18: Unit HP and Hydrocom Setting

Unit HP and Hydrocom Setting

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

9:00:0

0

10:15:0

0

11:30:0

0

12:45:0

0

14:00:0

0

15:15:0

0

16:30:0

0

17:45:0

0

19:00:0

0

20:15:0

0

21:30:0

0

22:45:0

0

0:00:0

0

1:15:0

0

2:30:0

0

3:45:0

0

5:00:0

0

6:15:0

0

7:30:0

0

8:45:0

0

10:00:0

0

11:15:0

0

12:30:0

0

time

HP

-20

0

20

40

60

80

100

120

%H

ydrocomS

etting

D01M-REAL-PWR

D01M-HYDROCOM-HE

Figure 19 Cylinder and Frame Stretch Vibration

Frame and Cylinder Stretch (overall ips 5-200 Hz)

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

085736

.DAQ

101946

.DAQ

1031

46.DAQ

104354

.DAQ

105554

.DAQ

110754

.DAQ

111955

.DAQ

1131

55.DAQ

114355

.DAQ

115556

.DAQ

123533

.DAQ

133533

.DAQ

1433

11.DAQ

1533

11.DAQ

1633

11.DAQ

1733

12.DAQ

1833

12.DAQ

1933

12.DAQ

2033

12.DAQ

2133

13.DAQ

2233

13.DAQ

233336

.DAQ

0033

14.DAQ

0133

14.DAQ

0233

14.DAQ

0333

14.DAQ

0433

15.DAQ

0533

15.DAQ

0633

15.DAQ

0733

15.DAQ

083209

.DAQ

0924

17.DAQ

1024

17.DAQ

1124

17.DAQ

time

ipspk

cylinder stretch (overall ips 5-200 Hz)

cylinder stretch (overall ips 5-200 Hz)

20% torque(100% Hydrocom)

97.4% torque (100% Hydrocom)104% torque(100% Hydrocom)

Vary Hydrocom



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Figure 20 Main Bearing Strain Response

Pin Side Main Bearing Strain Response

0

50

100

150

200

250

300

350

400

450

0 200 400 600 800 1000 1200 1400 1600 1800

minutes from SDCM starts

ustrainpk-pk

A ustrain pk-pk

C ustrain pk-pk

E ustrain pk-pk

43 ustrain difference



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IntroductionThis procedural write-up is to provide guidance for field compressor / driver alignment /

re-alignment. The purpose is to document job specific activities into an organized check-list that will result in a properly supported and well-aligned drive train.

Objective:

To obtain Driver (Gas or Electric) and Compressor alignment tolerances to the following spec. (Verify all

readings with AlignmentMaster2)

Driver and Compressor Frames Max allowable misalignment from anchor bolt to anchor

bolt, (or bearing saddle to bearing saddle) is .002 w/ .004 overall.

Driver and Compressor Twist Max allowable is of the bearing clearance at any bearing

saddle location. Example - .006 bearing top clearance, equals a .003 side cl., which equals

a max. allowable twist of .0015.

Install and maintain Crosshead and Compressor alignment to + .004 / ft. and -.000 of the

frame overall list, with both crosshead and compressor in-plane, w/ all bottles and piping

attached.

The following procedural steps are intended to address initial installation procedures as well as any re-

alignment issues that may present themselves.

1. Pre-job Checkl ist Coordinate compressor and driver manufacturers technical assistance involvement.

Develop EPE written lock out/tag out work procedure for these realignment activities.

The following information is required prior to physically starting the re-alignment.

Determine (Measure) the shim thickness required to replace the individual

(Loose) shims now in place. (Ideally, one shim plate and one shim pack per bolt)

Order replacement shims. (Shims must be on site prior to disassembly)

Note:Replacement shims (302ss min.) are to be a 1 piece solid, plus a laminated pack of no more

than .003, with .002 laminations preferred, and .125 max. The thickness of the one-piece

solid shim is determined by the measurements above, and may be location specific.

Note:Compressor and Driver Frame measurements to be precision

measurements using instruments within + / - .001 resolution. I.e. Optical

or Laser Scope, Lectromaster level, etc



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o Gather the following unit information:

1) Compressor Frame Length ---------------------(inches): ________

2) Compressor Frame Width ----------------------(inches): ________

3) Drive-train Coupling Length ----------------------(inches): ________

4) Coupling alignment tolerance --------------------(inches): ________

5) Comp. Published thermal growth (.xxx /100deg. F) : ________

6) Driver Published thermal growth (.xxx/100deg. F) : ________

7) Distance from Compressor Frame to Driver Frame

(total distance between frame and driver) -------(inches): ________

8) Driver Frame Length -------------------------------(inches): ________

9) Driver Frame Width --------------------------------(inches): ________

10) Compressor Main Bearing Clearance ------------(inches): ________

11) Driver Main Bearing Clearance -------------------(inches): ________

12) Drive-train Coupling flange bolt torques

Compressor Flange --------------------------------------(ft-lb):

________Driver Flywheel ------------------------------------------(ft-lb): ________

13) Compressor Frame Anchor Bolt torque ------------(ft-lb): ________

14) Compressor Crosshead Pedestal Bolt torque ------(ft-lb): ________

15) Compressor Cylinder Peanut Flange bolt torque --(ft-lb): ________16) Driver Frame Anchor Bolts -------------Torque (ft-lb): ________ or --------

------------------Stretch requirements (inches): ________

17) Verify all Manufacturers Special Tools are available and are in proper working

condition ------------ Compressor: ___________

------------- Driver : ___________

18) 16 Bottle & Spool Flange Gaskets

Quantity ______ Part Number: ___________ Deliv date: ________

19) 16 Bottle & Spool Flange PTFE Coated Bolts

Quantity: ______ Part Number: _________Deliv. date: ________

20) Compressor Peanut Flange Gaskets

Quantity: _____ Part Number: __________ Deliv. date: ________

21) Compressor to Crosshead Guide Gaskets

Quantity: _____ Part Number: ___________ Deliv. date: ________22) Recommended Driver to Compressor cold alignment --------------------

Driver = Top ______ Bot ______ L ______ R ______

Compressor = Top ______ Bot ______ L ______ R ______

23) Acceptable coupling alignment limits :

COLD T_____ B _____ L_____ R _____

HOT T_____ B _____ L _____ R _____

Note:Use Compressor as reference for Left and Right.

2. Pre-Job Meeting

A pre-job meeting needs to be conducted to discuss and clar if y

many items contained with in thi s document. Th is is a complex process, and as such, not all

items of concern / pr e-experienced can be satisfactor il y addressed with a wri tten explanation

and/or procedure.



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Pre-Job Meeting required attendance:

o Plant Services and Engineering

o Division / Area

o If under Warranty:

o OEM Compressor and Driver (Driver optional)

o Contractor

3. NEW Installation

SKID Mountingo Mount 4 to 6 leveling pads ( Vibracon or equivalent)

o Securing temporarily with mortar to foundation top.

o Using a precision leveling device (accuracy + .0015 / 40) level all pads to earth,

and lock in place.

o Place skid on pads and let set / stand for min. 24 hrs.

o Adjust jackscrews to support skid in non-stressed position, and remove leveling

pads.

o Pour grout

4. Activi ties Prior to Disassembly

Before Shutdown Determine deteriorated equipment support condition issues:

Loose anchor bolts and shims by location.

Broken or cracked anchor bolts on driver, compressor or secondary

discharge bottles.

Loose discharge bottle (primary & secondary) wedges

After Shutdown Hot (48 hrs running time) Drive trains hot coupling alignment, measure & record within 15 minutes of shutdown.

Compressor crosshead guide clearances, measure and record within 30 minutes of shutdown.

Gas reciprocating drivers hot crankshaft web deflections, if attainable.

After Shutdown Cold Record as-found compressor conditions on EPCs Gas Path Integrity Condition (GPIC) data sheets;

Rod run-out & wear

Cylinder bore wear

Piston wear band & ring condition

Crosshead guide & cylinder bore slope, measured with a precision

Machinists level in thousandths of an inch/foot.

Using a precision elevation measurement device, determine existing drive-train alignment condition of

the following equipment, recording elevations Data Sheets: (Has scope been calibrated on site via

AlignmentMaster2

procedure) __________

Compressor frame RE initial

Cylinder suction flange planes, CE & HE

Driver frame feet

Note:Compressor and Driver Frame measurements to be precision



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measurements using instruments within + / - .001 resolution. I.e. Optical

or Laser Scope, Lectromaster level, etc.

2. Major Equipment Disassembly Sequence

When removing the following items, record any unusual conditions for review when reassembly begins;i.e. piping misalignment, binding, flange misalignment (flange to flange or flange to Compressor), gasket

failures or pinching, piping angular misalignment, etc.

Disassemble the process gas piping and compressor as follows:

1) Remove compressor suction spools.2) Remove compressor suction bottles.

Note:Place bottles beside compressor on concrete slab with plywood under flanges to protect

gasket-sealing surfaces.

3) Remove flange bolts between discharge bottles.4) Remove compressor discharge peanut flange bolts, then remove restriction orifice/gasket

holder.

5) Remove compressor piston rod assembly, mark piston and balance nutswith cylinder number, then place assemblies on plywood with balance

nuts installed to protect threads.

6) Remove compressor to crosshead mounting bolts.7) Move compressor cylinders away from crossheads approximately 6, supporting cylinder

securely on discharge bottle flange & wood timbers under outboard end.

8) Remove, clean and replace shims under compressor frame, crossheadpedestal and driver anchor bolts.

9) Re-torque compressor frame, pedestal and driver anchor bolts to 50% of

Manufacturers specified value.

10) Remove drive-train coupling.

Note:Carefully place & store all removed critical compressor fasteners in plastic buckets,

protecting threads from impact damage.

3. Drive-train Re-alignment /Shimming Procedure

Note: Verify that the compressor and Driver Jackscrews do not distort or otherwise damage the

soleplates. In some cases a pancake jack must be used.

With all compressor frame, pedestal and driver anchor bolts re-torqued to at least 50% full value:

1) Re-measure all precision elevation readings (compressor frame top and driver mounting feet),

recording information on the sheets provided.

2) Using EPEs AlignmentMaster2, process readings

3) Make shim adjustments as required utilizing EPCs AlignmentMaster2 LIST function.

Note:Maintain compressor and driver coupling end 0 reference points to

minimize affect on coupling alignment.

4) After each shimming adjustment, re-torque anchor bolts to 50% of manufacturers specified

value and verify elevation adjustments using

precision measurement device, recording readings on the sheets

provided.

5) Repeat steps 2, 3, and 4 until alignment of both Driver and Compressor frames are acceptable

per EPCs AlignmentMaster2 and Web. Limits.



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6) Preload crosshead guide pedestals to approximately the same side-to-side plane as the

compressor frame, using up to 0.012 shim under crosshead pedestal. Vary the pre-load

between .005 and .012 to obtain the upper recommended value clearance. Example

recommended x-head running clearance is .010 to .015, adjust the preload to obtain a

clearance between .013 and .015.

Note:After shimming adjustments, assure that the recommended crosshead

running clearance is not reduced more than .001 and is not less than the

minimum allowable clearance.

4. Drive-train Coupling Alignment Procedure

With compressor and driver frames acceptably aligned and all anchor bolts torqued to100% value, proceed as follows:

1) Using either a Laser coupling alignment tool or the Reverse Dial indicator method;

Measure drive-train coupling alignment

Note:DO NOT shim any individual feet or foot (i.e. soft foot method) that

might be indicated by the alignment readings. (We want to leave the unit flat) TheAlignmentMaster2 program will align the comp and driver to the same slope.

2) Using the compressor frame as a fixed point, improve alignment as required by moving the

driver frame as a whole i.e. all feet get same shim adjustment.

Note:Horizontal frame movements can be made independently at each end.

5. Equipment Reassembly Procedure

Reassemble the compressor as directed by the compressor manufacturer representative (if present) or

OEM Technical Manual. Reinstall associated process gas piping and associated equipment as follows:

1) Reinstall the compressor cylinders to the crosshead guides, hand tightening four corner bolts.

Note:Inspect all critical fastener threads for damage prior to install. Lubricate fastener threads

and under bolt heads before installation by hand. All fasteners should turn freely be hand.

2) Using a precision machinists level, adjust cylinder roll about the mounting bolts to align thesuction flange plane with the compressor frames (end to end) slope plane, then torque all

mounting bolts to specified value.

Note:Lower discharge bottle as required to facilitate cylinder installation and rotation.

3) Verify that cylinder and crosshead bores are in the same plane with a precision machinistslevel, record readings.

4) Install cylinders HE heads, with bolt snugged to prevent cylinder bore distortion when bottleflange bolts are torqued.

5) Mount discharge bottles to the compressors cylinders with new gaskets in the orifice holder,checking for proper alignment and fit-up.

Note:All cylinder peanut flange bolts shall be installed by hand. Adjust bottles vertical and

horizontal position as required for ease of bolt installation.



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6) Using discharge bottle wedges, support the compressor cylinders so their bores are in thesame plane as the crosshead.

7) Torque cylinder to discharge bottle flange bolts to the value specified.8) Install new gaskets and bolts, then torque primary to secondary discharge bottle flange bolts

to the value specified for bolt coating.

Note:Secondary discharge bottle wedge adjustment may be required to facilitate 16 600#ANSI flange alignment.

9) Hand tighten discharge bottle wedges and hold down straps as required.10) Re-measure cylinder elevations using precision measurement device, recording readings on

the sheets provided. Verify that compressor frame alignment is still good.

11) Reinstall the suction bottles to the compressors cylinders with new gaskets in the orificeholder, checking for proper alignment and fit-up.

Note:All cylinder flange bolts shall be installed by hand. Adjust bottles vertical and horizontal

position as required for ease of bolt installation.

12) Reinstall suction spools using new gaskets and bolts, then torque flange bolts to the valuespecified for bolt coating.

13) Install compressors piston rod assemblies and HE heads, then torque fasteners and balancenuts as specified.

14) Re-torque all bolts per OEM recommended lubricant, sequence, and pre-stress (PSI) tables.15) Loosen the bottle supports and measure (dial indicator) the overall drop. Re-tighten the

supports to gain back of the observed drop.

16) Record the compressor cylinders as-left conditions on EPCs Gas Path Integrity Check(GPIC) forms.

17) Re-measure compressor cylinder elevations using precision measurement device, recordingreadings on the sheets provided. Verify that compressor frame alignment is still good.

18) Reinstall the drive-train coupling

6. Final Assembly Checks & Verifications

Re-measure compressor frame & driver foot elevations using precision measurement device, recording

readings on the sheets provided.

Confirm as-left condition is within EPCs AlignmentMaster2 specifications.

Confirm all compressor as-left conditions on EPCs Gas Path Integrity Check

(GPIC) forms, In addition to:

o Compressor and Driver Thrust measurements

Compressor and driver frame jack bolts (2 per corner) are loosened at least 1 away from the frame.

Record the driver conditions on appropriate EPC forms:

Gas Reciprocating Web deflections

Electric Motors Air gap Coupling Alignment within OEM specs.

7. TGP Startup procedures

Verify all flange (suction and discharge) bolts are torqued

Verify all piping flange bolt are torqued

Verify all GPIC work completed per COPP Section 105.1



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Verify engine and compressor-frame thrust clearances

Remove locks on affected unit valves

Purge unit per approved procedures

Pressurize unit to 50 PSI; perform leak check

Increase pressure in increments of 100 PSI to 400 PSI, performing leak checks at each step.

Increase unit to line pressure; perform leak check

Bar unit at least one complete revolution to ensure no mechanical block Perform final walk-around inspection prior to first crank

Crank unit on starter while listening for knocks, etc.

Start unit, run to the point of loading, then shut down; inspect crosshead clearances and

compressor cylinder elevations; note compressor-frame vibration readings at unit panel

Start unit, place on-line; operate loaded for 48 hours while noting frame vibration readings at unit

panel; shut down and perform hot engine web deflection readings; check compressor elevations; check

crosshead clearances; check coupling alignment; check wedges under discharge bottles.

Obtain frame and piping vibration readings (EPC Reliability Specialist or

contract specialist).

8. (30) Day Follow-up Maintenance Checks

Record locations of any loose shims.

While running, verify anchor bolt torque is adequate by feeling for relative movement at each interface.

Re-torque anchor bolts as required to tighten shim-stack.

Discharge bottle wedges providing positive lift without crosshead guide clearance deterioration.

Crosshead clearances hot are within manufacturers tolerances.

Hot coupling alignment is within coupling tolerances.

With unit hot measure Compressor and Frame planes. Using the bottle supports, adj. as necessary toobtain equal planes, and lock in place.

NOTES ***

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Procedure signed OFF by Date ________________



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Area / Division Rep Plant Services Rep.

Rev. 1.0

Documents

Criticality of High Speed Separable Alignment