Calgary Symposium Plan 54
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User Experience with Plan 54 Seal Flush System 2007
.
Presenters: • Michel Boutin: Machinery Engineer Shell Scotford Refinery • Brad Hatton: Machinery Engineer Shell Scotford Refinery
Definition – Plan 54
• Pressurized external barrier fluid system supplying clean fluid to the seal chamber. Circulation is by an external pump or pressure source. Reservoir pressure is greater than process pressure being sealed. • API 682
Plan 54 AP I Plan 54 C lean E xternal S ource of P ressurized B arrier Fluid
Overview - Scotford
• Barrier fluid system is common to many pumps in the unit. (12 Pumps with 15 seals) • Finished product (ULSD) is the barrier fluid. • Control the barrier fluid pressure at 140 kPag (20psig) above the stuffing box pressure.
Overview (con’t) • System pressure is maintained by a main pressure control valve on the skid. • Pressure control to each pump is by a local control valve. • Flow control is maintained by a restriction orifice. • Cooling of barrier fluid is by an Air Cooled Heat Exchanger
Skid Details
• The barrier fluid skid consists of: – 2 IMO screw pumps – Air Cooled Heat Exchanger – Duplex Filters – System reservoir
Pump Details
• Each pump has a local Pressure Reducing Valve (PRV) to drop the header pressure • One PRV for each pair of pumps • Local Flow Indications to each seal. • Flow orifice located down stream of each seal
Process P &ID
Typical Pump P&ID
Operating History • System was chemically cleaned and flushed during commissioning • Used milk pads at each seal to check for cleanliness • Found three failed seals upon start up • Flow indicators showed high flows and one was leaking to grade
Reservoir Level History from Start-up V2026 Barrier Fluid Reservoir 20V26CP2:LI20471.PNT 62.4870
100 80 70 60 50 40 30 20 10 0 03/05/2006 12:00:00 AM
224.96 days
10/16/2006 12:00:00 AM
Set points • Alarms were set on the flows to each seal High Flow was set@ 90% of instrument range (2X Normal flow) Low Flow was set @ value from Seal Supplier Low Pressure Alarm set at 70 kPag (10 psig) above stuffing box pressure.
Set Points (con’t)
• • • •
Differential Pressure across the filters High Temp Alarm (50C) High Pressure Alarm on Reservoir. High and Low Level Alarm on Reservoir
Troubleshooting • Detecting small leaks on the inner seal is next to impossible. Trending on the flows helps but small leaks are not detectable. • Leaks on the secondary seal will show barrier fluid on the pump • Trouble shooting guide for Operations was generated
Troubleshooting (con’t)
• Would need to systematically isolate the spare pumps and trend the reservoir level over a few days. • Since all seals leak in order to provide lubrication we may not have a “leak” at all • Finished product (ULSD) is the barrier fluid we are not contaminating the system
Learnings From Start-up • Flushing of the system took longer than expected even though it was chemically cleaned and under an N2 blanket during construction. • Remaining water in the skid from the OEM was frozen and only after the system was started up did the ice “thaw” releasing small debris into the piping.
Learning’s (con’t) • We did not flush through each seal and had to install a temporary jump-over to avoid flushing debris thru the seal. • The reservoir does not have a weir or baffle plate. Suction to pumps is located on the bottom. Future projects should have it on the side or use a stand pipe inside. • No Source of heat for the fluid. Relying on the heat generated by the seals.
Learning’s (con’t)
• The piping run to each pump has a lot of low points and high points. Should be stream lined to push any vapour in the piping up and though the seals.
First Major Failure • Operators have been making entries into the logs that this system has been operating poorly from Nov 21 – Dec 5, 2006 during a cold snap • December 5th, 2006 after an extended cold snap, local ambient temperatures rose above 0oC • First indication of trouble was the loss of system pressure the morning of Dec 5th.
First Major Failure (Con’t) • IMO pump started to “cavitate” • Operators started the spare, believing that the first pump failed. • Filter differentials on the skid were erratic. • Barrier Fluid usage as indicated by the level in the surge vessel had not been the same as it had been in the past.
First Major Failure (Con’t) • Fluid sample from the surge vessel was the first indication that there was a large amount of water in the system. • System contents was drained, and filled at the same time to purge the system of water. • Second pump quickly showed signs of failed internals.
Reservoir Level Leading up to Failure V2026Barrier FluidReservoir 20V26CP2:LI20471.PNT 61.8730
100 80 70 60 50 40 30 20 10 0 10/01/200612:00:00AM
70.04days
12/10/200612:00:00AM
System Pressure Failure Trend Supply to Pumps 3000 100
20E14CP2:PC20411.MEAS 31.6277 kPag 20E14CP2:PC20411.OUT 0.0000 % 20E14CP2:PC20411.SPT 31.6277 kPag 20E14CP2:PDI20472.PNT -0.1155 kPa
3000 100
2500
2000
1500
1000
500
0 0 0 0 12/05/2006 12:00:00 AM E2014 BARRIER COOLR TO HDR E2014 BARRIER COOLR TO HDR E2014 BARRIER COOLR TO HDR S2022A/B BARRIER FILTERS
24.00 hours
12/06/2006 12:00:00 AM
System Pressure Failure Trend Supply to Pumps 3000 100
20E14CP2:PC20411.MEAS 1408.6914
3000 100
2500
kPag 20E14CP2:PC20411.OUT
2000
0.0000 % 20E14CP2:PC20411.SPT 1408.6914 kPag 20E14CP2:PDI20472.PNT 6.1878 kPa
1500
1000
500
0 0 0 0 12/05/2006 8:00:00 AM E2014 BARRIER COOLR TO HDR E2014 BARRIER COOLR TO HDR E2014 BARRIER COOLR TO HDR S2022A/B BARRIER FILTERS
2.00 hours
12/05/2006 10:00:00 AM
First Major Failure (Con’t) • Process Unit was shutdown, to preserve critical equipment. • Two teams were set up. One to repair and flush the system, the other to investigate the failure. • Being a new unit, the system had functional instrumentation
Major Findings from First Failure • One seal that was not designed for the full Plan 54 system pressure • Failed one seal before the major incident. Pump is in water service. Analysis showed it had a reverse pressure event. • Failed another seal in water service. It had been suspected a procedural error in checking for leakage during the first event.
Major Findings • No way to tell when there is water in the system. • No easy way to drain water from the system. • Circulation pump selection is acceptable for a “clean” system, but did not take in account for off design conditions. • EHT was not considered in the project
Pump Seal Failure in Water Service
Pump Seal Failure in Water Service
Proposed Post Failure Changes • Installation of a water boot • Installation of a conductivity detector for water • Proposed new pump to handle high levels of water • Working to remove one water pump from the system (H2S Levels)
Implemented Post Failure Changes
• Developed Procedure to test individual pump seals for integrity before start-up. • Complete spare pump now on the shelf. • PM plan to replace pump and inspect. • EHT being installed at low points.
Minor Failure in May 2007
• Circulation Pump pressure started to fall, and operators detected water in the system again. • Immediately started to conduct an online flush of the system to save the second IMO pump. • P-2005 (“Sour” Water from Driers) was suspected leaking water into the Barrier Fluid System, as the water was “clean”.
Minor Failure in May 2007 • Removed seal from pump did not indicate a failure of the seal. • Had the revelation that the barrier system pressure was too low for the P-2005’s • Pumps were rebuilt shortly after start-up, and after the initial barrier pressure survey. • Stuffing box pressure was higher than the set pressure for the barrier fluid. • Adjusted barrier pressure from 1250 kPa to 1800 kPa.
P2005A/B Sour water 2000 100 2000 0.6
20P05CP2:PC20551.MEAS 1801.4902 20P05CP2:PC20551.OUT 31.4801
0.6
1500
20P05CP2:PC20551.SPT 1800.0000 20P05CP2:FI20549.PNT 0.5514 20P05CP2:FI20554.PNT 0.4921
1000
500 0 0 0 0.3 0.3 05/14/2007 3:12:32.363 PM P2005A/B BARRIER FLUID P2005A/B BARRIER FLUID P2005A/B BARRIER FLUID P2005A BARRIER FLUID P2005B BARRIER FLUID
7.04 days
05/21/2007 4:12:32.363 PM
Minor Failure in May 2007
• After the set pressure change, no major water excursions have occurred.
P-2008 Vacuum Pump Seals
• ANSI style seal, limited stuffing box size. • Moved to a TiC/SiC seal face combination due to initial seal failures during start-up.
August 29 – 30, 2007 Operation • Numerous Stop Starts on both pumps. • Started another rapid loss of level in the surge drum, greater that what we have seen in the past. • Barrier fluid flow was not that much higher than what it was in the past. • Decided to swing to P-2008A and isolate P-2008B
September 5, 2007 Operation
• Isolated P-2008B and the level in the surge drum stabilized. • Maintained operation of P-2008A
V2026 Barrier Fluid Reservoir 20V26CP2:LI20471.PNT 84.4665 %
100 80 70 60 50 40 30 20 0 08/28/2007 11:40:57.985 AM V2026 BARRIER FLUID DRuM
14.04 days
09/11/2007 12:40:57.985 PM
P2008A/B Vacuum 1200 100
1200 0.5 0.5
2
20P08CP2:PC20561.M EAS 238.2031 kPag 20P08CP2:PC20561.OUT
2
1000
68.2035 %
800
20P08CP2:PC20561.SPT 232.0000 kPag 20P08CP2:FI20559.PNT
600 400
-0.0002 Am3/h 20P08CP2:FI20564.PNT -0.0004
200 0 0 0 0.2 0.2 08/28/2007 11:44:26.677 AM P2008A BARRIER P2008A BARRIER P2008A BARRIER P2008B BARRIER
0
FLUID FLUID FLUID FLUID
P2008A BARRIER FLUID P2008A LIQ RINGRUN STAT P2008B LIQ RINGRUN STAT
0 14.04 days
09/11/2007 12:44:26.677 PM
Am3/h 20P08CP2:XI20734.CIN 1 20P08CP2:XI20735.CIN 0
Present Operation of the Reservoir Level V2026 Barrier Fluid Reservoir 20V26CP2:LI20471.PNT 65.7390
100 80 70 60 50 40 30 20 10 0 08/07/2007 12:00:00 AM
90.04 days
11/05/2007 12:00:00 AM
Present Water Status in the System.
• We are still building water in the system • The rate of water build up is very slow. • The water is not sour, which indicates possibly three sources of water.
October 11th Sample
October 29th Sample
Barrier Fluid Skid
Local Pump Control
Local Pump Control
Barrier Fluid Skid
EHT/Temp Wrap for Winter
EHT @ P-2014A
Flow Indication Setup
Orifice Location
Piping @ P-2005
Control Station @ P-2008
Flow Indication @ P-2008
Outlet Piping @ P-2008
Outlet Piping from V-2021
Temperature Bypass on Skid
IMO Pump Orientation
System Pressure Control Station
.
End of Presentation
User Experience with Plan 54 Seal Flush System 2007
.
Presenters: • Michel Boutin: Machinery Engineer Shell Scotford Refinery • Brad Hatton: Machinery Engineer Shell Scotford Refinery
Definition – Plan 54
• Pressurized external barrier fluid system supplying clean fluid to the seal chamber. Circulation is by an external pump or pressure source. Reservoir pressure is greater than process pressure being sealed. • API 682
Plan 54 AP I Plan 54 C lean E xternal S ource of P ressurized B arrier Fluid
Overview - Scotford
• Barrier fluid system is common to many pumps in the unit. (12 Pumps with 15 seals) • Finished product (ULSD) is the barrier fluid. • Control the barrier fluid pressure at 140 kPag (20psig) above the stuffing box pressure.
Overview (con’t) • System pressure is maintained by a main pressure control valve on the skid. • Pressure control to each pump is by a local control valve. • Flow control is maintained by a restriction orifice. • Cooling of barrier fluid is by an Air Cooled Heat Exchanger
Skid Details
• The barrier fluid skid consists of: – 2 IMO screw pumps – Air Cooled Heat Exchanger – Duplex Filters – System reservoir
Pump Details
• Each pump has a local Pressure Reducing Valve (PRV) to drop the header pressure • One PRV for each pair of pumps • Local Flow Indications to each seal. • Flow orifice located down stream of each seal
Process P &ID
Typical Pump P&ID
Operating History • System was chemically cleaned and flushed during commissioning • Used milk pads at each seal to check for cleanliness • Found three failed seals upon start up • Flow indicators showed high flows and one was leaking to grade
Reservoir Level History from Start-up V2026 Barrier Fluid Reservoir 20V26CP2:LI20471.PNT 62.4870
100 80 70 60 50 40 30 20 10 0 03/05/2006 12:00:00 AM
224.96 days
10/16/2006 12:00:00 AM
Set points • Alarms were set on the flows to each seal High Flow was set@ 90% of instrument range (2X Normal flow) Low Flow was set @ value from Seal Supplier Low Pressure Alarm set at 70 kPag (10 psig) above stuffing box pressure.
Set Points (con’t)
• • • •
Differential Pressure across the filters High Temp Alarm (50C) High Pressure Alarm on Reservoir. High and Low Level Alarm on Reservoir
Troubleshooting • Detecting small leaks on the inner seal is next to impossible. Trending on the flows helps but small leaks are not detectable. • Leaks on the secondary seal will show barrier fluid on the pump • Trouble shooting guide for Operations was generated
Troubleshooting (con’t)
• Would need to systematically isolate the spare pumps and trend the reservoir level over a few days. • Since all seals leak in order to provide lubrication we may not have a “leak” at all • Finished product (ULSD) is the barrier fluid we are not contaminating the system
Learnings From Start-up • Flushing of the system took longer than expected even though it was chemically cleaned and under an N2 blanket during construction. • Remaining water in the skid from the OEM was frozen and only after the system was started up did the ice “thaw” releasing small debris into the piping.
Learning’s (con’t) • We did not flush through each seal and had to install a temporary jump-over to avoid flushing debris thru the seal. • The reservoir does not have a weir or baffle plate. Suction to pumps is located on the bottom. Future projects should have it on the side or use a stand pipe inside. • No Source of heat for the fluid. Relying on the heat generated by the seals.
Learning’s (con’t)
• The piping run to each pump has a lot of low points and high points. Should be stream lined to push any vapour in the piping up and though the seals.
First Major Failure • Operators have been making entries into the logs that this system has been operating poorly from Nov 21 – Dec 5, 2006 during a cold snap • December 5th, 2006 after an extended cold snap, local ambient temperatures rose above 0oC • First indication of trouble was the loss of system pressure the morning of Dec 5th.
First Major Failure (Con’t) • IMO pump started to “cavitate” • Operators started the spare, believing that the first pump failed. • Filter differentials on the skid were erratic. • Barrier Fluid usage as indicated by the level in the surge vessel had not been the same as it had been in the past.
First Major Failure (Con’t) • Fluid sample from the surge vessel was the first indication that there was a large amount of water in the system. • System contents was drained, and filled at the same time to purge the system of water. • Second pump quickly showed signs of failed internals.
Reservoir Level Leading up to Failure V2026Barrier FluidReservoir 20V26CP2:LI20471.PNT 61.8730
100 80 70 60 50 40 30 20 10 0 10/01/200612:00:00AM
70.04days
12/10/200612:00:00AM
System Pressure Failure Trend Supply to Pumps 3000 100
20E14CP2:PC20411.MEAS 31.6277 kPag 20E14CP2:PC20411.OUT 0.0000 % 20E14CP2:PC20411.SPT 31.6277 kPag 20E14CP2:PDI20472.PNT -0.1155 kPa
3000 100
2500
2000
1500
1000
500
0 0 0 0 12/05/2006 12:00:00 AM E2014 BARRIER COOLR TO HDR E2014 BARRIER COOLR TO HDR E2014 BARRIER COOLR TO HDR S2022A/B BARRIER FILTERS
24.00 hours
12/06/2006 12:00:00 AM
System Pressure Failure Trend Supply to Pumps 3000 100
20E14CP2:PC20411.MEAS 1408.6914
3000 100
2500
kPag 20E14CP2:PC20411.OUT
2000
0.0000 % 20E14CP2:PC20411.SPT 1408.6914 kPag 20E14CP2:PDI20472.PNT 6.1878 kPa
1500
1000
500
0 0 0 0 12/05/2006 8:00:00 AM E2014 BARRIER COOLR TO HDR E2014 BARRIER COOLR TO HDR E2014 BARRIER COOLR TO HDR S2022A/B BARRIER FILTERS
2.00 hours
12/05/2006 10:00:00 AM
First Major Failure (Con’t) • Process Unit was shutdown, to preserve critical equipment. • Two teams were set up. One to repair and flush the system, the other to investigate the failure. • Being a new unit, the system had functional instrumentation
Major Findings from First Failure • One seal that was not designed for the full Plan 54 system pressure • Failed one seal before the major incident. Pump is in water service. Analysis showed it had a reverse pressure event. • Failed another seal in water service. It had been suspected a procedural error in checking for leakage during the first event.
Major Findings • No way to tell when there is water in the system. • No easy way to drain water from the system. • Circulation pump selection is acceptable for a “clean” system, but did not take in account for off design conditions. • EHT was not considered in the project
Pump Seal Failure in Water Service
Pump Seal Failure in Water Service
Proposed Post Failure Changes • Installation of a water boot • Installation of a conductivity detector for water • Proposed new pump to handle high levels of water • Working to remove one water pump from the system (H2S Levels)
Implemented Post Failure Changes
• Developed Procedure to test individual pump seals for integrity before start-up. • Complete spare pump now on the shelf. • PM plan to replace pump and inspect. • EHT being installed at low points.
Minor Failure in May 2007
• Circulation Pump pressure started to fall, and operators detected water in the system again. • Immediately started to conduct an online flush of the system to save the second IMO pump. • P-2005 (“Sour” Water from Driers) was suspected leaking water into the Barrier Fluid System, as the water was “clean”.
Minor Failure in May 2007 • Removed seal from pump did not indicate a failure of the seal. • Had the revelation that the barrier system pressure was too low for the P-2005’s • Pumps were rebuilt shortly after start-up, and after the initial barrier pressure survey. • Stuffing box pressure was higher than the set pressure for the barrier fluid. • Adjusted barrier pressure from 1250 kPa to 1800 kPa.
P2005A/B Sour water 2000 100 2000 0.6
20P05CP2:PC20551.MEAS 1801.4902 20P05CP2:PC20551.OUT 31.4801
0.6
1500
20P05CP2:PC20551.SPT 1800.0000 20P05CP2:FI20549.PNT 0.5514 20P05CP2:FI20554.PNT 0.4921
1000
500 0 0 0 0.3 0.3 05/14/2007 3:12:32.363 PM P2005A/B BARRIER FLUID P2005A/B BARRIER FLUID P2005A/B BARRIER FLUID P2005A BARRIER FLUID P2005B BARRIER FLUID
7.04 days
05/21/2007 4:12:32.363 PM
Minor Failure in May 2007
• After the set pressure change, no major water excursions have occurred.
P-2008 Vacuum Pump Seals
• ANSI style seal, limited stuffing box size. • Moved to a TiC/SiC seal face combination due to initial seal failures during start-up.
August 29 – 30, 2007 Operation • Numerous Stop Starts on both pumps. • Started another rapid loss of level in the surge drum, greater that what we have seen in the past. • Barrier fluid flow was not that much higher than what it was in the past. • Decided to swing to P-2008A and isolate P-2008B
September 5, 2007 Operation
• Isolated P-2008B and the level in the surge drum stabilized. • Maintained operation of P-2008A
V2026 Barrier Fluid Reservoir 20V26CP2:LI20471.PNT 84.4665 %
100 80 70 60 50 40 30 20 0 08/28/2007 11:40:57.985 AM V2026 BARRIER FLUID DRuM
14.04 days
09/11/2007 12:40:57.985 PM
P2008A/B Vacuum 1200 100
1200 0.5 0.5
2
20P08CP2:PC20561.M EAS 238.2031 kPag 20P08CP2:PC20561.OUT
2
1000
68.2035 %
800
20P08CP2:PC20561.SPT 232.0000 kPag 20P08CP2:FI20559.PNT
600 400
-0.0002 Am3/h 20P08CP2:FI20564.PNT -0.0004
200 0 0 0 0.2 0.2 08/28/2007 11:44:26.677 AM P2008A BARRIER P2008A BARRIER P2008A BARRIER P2008B BARRIER
0
FLUID FLUID FLUID FLUID
P2008A BARRIER FLUID P2008A LIQ RINGRUN STAT P2008B LIQ RINGRUN STAT
0 14.04 days
09/11/2007 12:44:26.677 PM
Am3/h 20P08CP2:XI20734.CIN 1 20P08CP2:XI20735.CIN 0
Present Operation of the Reservoir Level V2026 Barrier Fluid Reservoir 20V26CP2:LI20471.PNT 65.7390
100 80 70 60 50 40 30 20 10 0 08/07/2007 12:00:00 AM
90.04 days
11/05/2007 12:00:00 AM
Present Water Status in the System.
• We are still building water in the system • The rate of water build up is very slow. • The water is not sour, which indicates possibly three sources of water.
October 11th Sample
October 29th Sample
Barrier Fluid Skid
Local Pump Control
Local Pump Control
Barrier Fluid Skid
EHT/Temp Wrap for Winter
EHT @ P-2014A
Flow Indication Setup
Orifice Location
Piping @ P-2005
Control Station @ P-2008
Flow Indication @ P-2008
Outlet Piping @ P-2008
Outlet Piping from V-2021
Temperature Bypass on Skid
IMO Pump Orientation
System Pressure Control Station
.
End of Presentation
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