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FSRUG . Feedwater Systems Reliability Users Group (Jan 2014) San Antonio, TX Stuffing Box Design & Configurations Presenter: Art Washburn, P.E. FSRUG. FSRUG. What is going on at this House? No Driveway, No Sidewalk….
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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…
FSRUGCity of Raleigh Public Utilities Water Booster StationPumps 45 Million Gallons per Day
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 #1 – Make Conservative Decisions Rule #2 – Maintain Design Control
FSRUG Two Rules: Rule #1 – Make Conservative Decisions Rule #2 – Maintain Design Control Plant Priorities:
FSRUG Two Rules: Rule #1 – Make Conservative Decisions Rule #2 – Maintain Design Control Plant Priorities: • Nuclear Safety
FSRUG Two Rules: Rule #1 – Make Conservative Decisions Rule #2 – Maintain Design Control Plant Priorities: • Nuclear Safety • Legal Requirements
FSRUG Two Rules: Rule #1 – Make Conservative Decisions Rule #2 – Maintain Design Control Plant Priorities: • Nuclear Safety • Legal Requirements • Efficiency
FSRUG Case 1: API Plan 11 – Packing Injection Flush (Original) Conditions: Excessive Packing Leakage - In Service - In Standby
FSRUG Case 1: Horizontal Multi-Stage Pump SectionalAux Service Water Pump Stg 1, 260 psi Psuction, 30 psi
FSRUG Case 1: In-Board Bearing Housing Assembly Conditions: Packing Leakage Sprays Directly on Bearing Housing Water Intrusion in Bearing Housing Displaces Approx. 50% of Oil
FSRUG Case 1: Stuffing Box Configuration (Original) Conditions: Lantern Ring Mis-Aligned Inner Packing Rings - What Can You Do For Me Today?
FSRUG Case 1: API Plan 11 – Injection Flush System (Original) Measured Stuffing Box Pressure Pstuff box, 260 psi Stg 1 – 260 psi Pstuff box, 260 psi Psuction, 30 psi
FSRUG Case 1: Stuffing Box Configuration (Updated)
FSRUG Case 1: API Plan 11 – Injection Flush System Pstuff box, 35 psi Stg 1 – 260 psi Pstuff box, 35 psi Psuction, 30 psi
FSRUG Case 1: Stuffing Box Configuration (Updated)
FSRUG Case 1: Stuffing Box Configuration (Updated) • Results: • Packing Sleeve Diameter, 4.000 Inches • 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 • 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 Case 1: Stuffing Box Configuration (Updated) • Analysis Process: • Simplify Equation of State to 2 Pressure Drop Devices or Less • 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
FSRUG Water Intrusion – Traditional Oil Deflector vs. INPRO Deflector See EPRI NMAC Lube Notes, November 2004, Bearing Operation with an Oil-Water Mixture
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 Case 2: API Plan 13 – Reverse Flush System (Original) Conditions: Excessive Packing 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 PSI Tubing dP, 3 PSI Packing, 3 PSI
FSRUG Case 2: API Plan 13 – Reverse Flush System (Updated) Analysis Seeks Mass Balance Thru the Bushing and Orifice: Bushing: Orifice:
FSRUG Case 3: API Plan 13 – Reverse Flush System (Original) 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 Case 3: API Plan 13 – Reverse Flush System (Updated) 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 Case 3: API Plan 13 – Reverse Flush System (Updated) 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 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
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)
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)
FSRUG 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 WHO IS THIS SYSTEM ENGINEER?
FSRUG TAYLOR SMITH – Comanche Peak
FSRUG THE (HAPPY) END QUESTIONS ?