FSRUG

FSRUG

Feedwater Systems Reliability Users Group (Jan 2014)

San Antonio, TX

Stuffing Box Design & Configurations

Presenter:

Art Washburn, P.E.

FSRUG

What is going on at this House?

No Driveway, No Sidewalk…

FSRUG

City of Raleigh Public Utilities Water Booster StationPumps 45 Million Gallons per Day

FSRUG

Virginia Beach Pump Station (Lake House)

FSRUG

Pump Station (Greek Architecture)

FSRUG

Office Building?...

FSRUG

Electrical Sub-Station

FSRUG

DISCUSSION POINTS• Two Rules to Get You Home and Plant Priorities

• Case 1: API Plan 11 – Packing Injection Flush… Exhibits Excessive Leakage During Operation and Standby (Horizontal Multi-Stage Pump in Auxiliary Service Water Service)

• Case 2: API Plan 13 – Reverse Flush System… Exhibits No Reverse Flush (Static System), Excessive Packing Leakage, Excessive Packing Sleeve Wear and Severe Stuffing Box Bearing Damage (Vertical Pump in Screen Wash Service)

• Case 3: API Plan 13 – Reverse Flush System… Exhibits Excessive Packing Leakage (Vertical Pump in Condensate Service)

• Case 4: API Plan 13 – Reverse Flush System with Bypass Port (Water Service and Hydrocarbon Service)

• Source References

FSRUG

Two Rules:

FSRUG

Two Rules:

Rule #1 – Make Conservative Decisions

FSRUG

Two Rules:


Rule #2 – Maintain Design Control

FSRUG

Two Rules:



Plant Priorities:

FSRUG

Two Rules:



Plant Priorities:

1. Nuclear Safety

FSRUG

Two Rules:



Plant Priorities:

1. Nuclear Safety

2. Legal Requirements

FSRUG

Two Rules:



Plant Priorities:

1. Nuclear Safety

2. Legal Requirements

3. Efficiency

Case 1: API Plan 11 – Packing Injection Flush (Original)

FSRUG

Conditions:

Excessive Packing Leakage

- In Service

- In Standby

Case 1: Horizontal Multi-Stage Pump SectionalAux Service Water Pump

FSRUG

Stg 1, 260 psi

Psuction, 30 psi

Case 1: In-Board Bearing Housing Assembly

FSRUG

Conditions:

Packing Leakage Sprays Directly on Bearing Housing

Water Intrusion in Bearing Housing Displaces Approx. 50% of Oil

Case 1: Stuffing Box Configuration (Original)

FSRUG

Conditions:

Lantern Ring Mis-Aligned

Inner Packing Rings - What Can You Do For Me Today?

Case 1: API Plan 11 – Injection Flush System (Original)

FSRUG

Stg 1 – 260 psi

Psuction, 30 psi

Pstuff box, 260 psi

Pstuff box, 260 psi

Measured Stuffing Box Pressure

Case 1: Stuffing Box Configuration (Updated)

FSRUG

Case 1: API Plan 11 – Injection Flush System

FSRUG

Stg 1 – 260 psi

Psuction, 30 psi

Pstuff box, 35 psi

Pstuff box, 35 psi


FSRUG


FSRUG

Results:

1.Packing Sleeve Diameter, 4.000 Inches

2.Required Flush for Packing or Mechanical Seal in Water Service and Fluid Temperature Less Than 150oF (1 GPM per 1 Inch of Shaft Diameter): 5 GPM

3.Stuffing Box Pressure: Maintains Positive Pressure, Easier to Adjust Packing, Reduced Frequency of Packing Adjustments, Eliminate Risk of Packing Spray Impingement on Bearing Housing


FSRUG

Analysis Process:

1.Simplify Equation of State to 2 Pressure Drop Devices or Less

2.Iterate Pressure Drop Determination for Both Devices to Share the Total Pressure Until a Mass Balance is Achieved (in GPM)

3. Result: Highly Predictable System Behavior

Water Intrusion – Traditional Oil Deflector vs. INPRO Deflector

See EPRI NMAC Lube Notes, November 2004, Bearing Operation with an Oil-Water Mixture

FSRUG

FSRUG

Case 2: API Plan 13 – Reverse Flush System (Original)

Conditions: Screen Wash Pump

Pdischarge, 85 PSI

Lantern Ring, Grease Filled

Packing exposed to pump discharge pressure

Bearing, High Pressure Breakdown Device(Static, melts)

FSRUG


Conditions:

ExcessivePacking Wear

FSRUG

Case 2: API Plan 13 – Reverse Flush System (Updated)

Conditions:

Screen Wash Pump

Pdischarge, 85 PSI

Replaced Bottom Packing with Spacer (Controlled Clearance)

Lantern Ring, Leak Off Thru Tubing (Orifice) to Sump

Bearing dP, 82 PSITubing dP, 3 PSIPacking, 3 PSI

FSRUG


Analysis Seeks Mass Balance Thru the Bushing and Orifice:

Bushing:

Orifice:

FSRUG


Conditions:

Condensate Pump

Excessive Packing Leakage

Pdischarge, 515 PSI

Pabove bushing, 170 PSI

FSRUG

Case 3: API Plan 13 – Reverse Flush System (Original)Conditions:

Condensate Pump

Bottom Lantern Ring Significantly Blocking Plan 13 Return to Suction

Lantern Ring Annulus Area too Small – Region Under Packing Does Not Depressurize

Packing Sleeve Wear Excessive

FSRUG


Conditions: Condensate Pump

Bottom Lantern Ring Resized to Assure Plan 13 Return is Not Blocked

Lantern Ring Annulus Area Increased to Allow Depressurizing Region 360 Degrees Around Shaft

FSRUG


Conditions:

Condensate Pump

Interstage Pressure Acting on Packing Rings is Low, Gland Water Injection Maintains Positive Pressure on Packing to Prevent Air In-Leakage

Packing Leak-Off Easily Controlled and Sleeve Wear Low

Condensate Pump

Interstage Pressure Acting on Packing Rings is Low, Gland Water Injection Maintains Positive Pressure on Packing to Prevent Air In-Leakage

Packing Leak-Off Easily Controlled and Sleeve Wear Low

FSRUG

Case 4: API Plan 13 – Reverse Flush System with Bypass Port(s)

FSRUG

Case 4: API Plan 13 – Reverse Flush System with Bypass Port(s)

Conditions:

Bypass Port(s) may Not be Required for Water Service

Bypass Port(s) are Required for Hydrocarbon Service (Low Specific Gravity Product)

SOURCE REFERENCES:• Centrifugal Pumps: Design & Application, Lobanoff and Ross

(practical application)• Centrifugal and Axial Flow Pumps, Stepanoff (theory)• Centrifugal Pumps, Gülich

• Vertical Turbine, Mixed Flow & Propeller Pumps, Dicmus• Centrifugal Pump Handbook, Sulzer• Pump Handbook, Karassik• Centrifugal Pump Clinic, Karassik• Centrifugal Pumps Selection & Operation, Karassik• Centrifugal Pumps, Karassik• In-Tandem 3.0 for Windows, EG&G Sealol (John Crane)• ABZ Inc, Design Flow Solutions Software

FSRUG

FSRUG

WHO IS THIS SYSTEM ENGINEER?

FSRUG

TAYLOR SMITH – Comanche Peak

THE (HAPPY) END

QUESTIONS ?

FSRUG

FSRUG

Documents

Transcript of FSRUG