chevron's experience with thermoplastic composites in rotating equipment
DESCRIPTION
This public access presentation was made by Chevron and shared during the Saudi Aramco Global Reliability Forum 2012. It is a description of Chevron´s experience using thermoplastic composite wear parts in centrifugal pumps over the last 20 years.TRANSCRIPT
Use of Thermoplastic Composites
in Rotating Machinery
Speakers: Walt McNutt – Chevron Refining Senior Machinery Reliability Leader Jonathan Pledger – Greene Tweed Vice President & General Manager, PetroChem & Power Greg Gedney – Greene Tweed SME Composites & Technology, PetroChem & Power
Thermoplastic Composites Use in
Rotating Machinery at Chevron Refining Chevron Refining has been using thermoplastic composites for over 20 years in
wear areas of centrifugal pumps
Chevron was involved in the initial development of using these materials and made
a number of mistakes that others can learn from.
0,00
2,00
4,00
6,00
8,00
10,00
12,00
MT
BR
in
YE
AR
S
Quarterly data
Chevron Refining - Jan 2003 to Dec. 2011
MTBR for all machinery
MTBR for Cent. Pumps
API Pumps - USA - Maint. Tech. article Oct. 2008
23,172 pieces of machinery
6,470 centrifugal pumps.
Data for our USA refineries only
Thermoplastics Composites Use in
Rotating Machinery at Chevron Refining
Our philosophy when we first started using Composites:
Install Composites in every pump possible and reduce the running
clearances.
Test Composites in unproven process streams.
Push the temperature limits from the vendors.
Plug end suction pump impeller balance holes to improve efficiency of
the pump. (PumpPac & control valve)
Chevron Refining findings with thermoplastic composites:
Very good for specific applications:
Pumps that actually run dry, such as LPG pumps, tankfield pumps, etc
Reduction of secondary damage and seizures
Multistage pumps:
Reduction of secondary damage;
Reduce damage during start-ups and upset conditions
Pumps with poor shaft stability. L/D issues
Increasing mechanical seal chamber pressures.
Thermoplastics Composites Use in
Rotating Machinery at Chevron Refining
Coupling Impeller
Gland
Impeller
Suction
Wear ring
Shaft
Sleeve
Shaft
Throat
Bushing Impeller
Back (hub)
Wear ring
Case
Back (hub)
Wear ring
Case
Suction
Wear ring
Thrust
Bearing
Bearing
Housing
Oil
Rings
Mechanical
Seal Seal
Chamber
Radial
Bearing
Sump
Bottle
Thrust
Bearing
Cover
Volute
Case
Backup
Plate
Suction
Flange
Discharge
Flange
Cartridge
Seal Drive
collar
End Suction
Single Stage
Centrifugal Pump
Thermoplastics Composites Use in
Rotating Machinery at Chevron Refining
End Suction
Single Stage
Centrifugal Pump
Older API pumps were
designed with packing to
stop the product from
leaking to atmosphere.
This acted as a bearing
for the shaft to support
the impeller movement.
Thermoplastics Composites Use
in Rotating Machinery at Chevron
Refining
End Suction
Single Stage
Centrifugal Pump
You can install the
thermoplastic composite
for impeller wear rings at
a clearance of ½ API-
610 standard metal wear
ring clearance.
This tighter clearance
will provide additional
stability of the shaft
vibration.
Thermoplastics Composites Use
in Rotating Machinery at Chevron
Refining
End Suction
Single Stage
Centrifugal Pump
In order to maintain
better mechanical seal
life, you want to increase
the pressure in the seal
chamber.
Running a thermoplastic
composite material for
the throat bushing with
reduced clearances can
reduce the pressure loss
back into the pump.
Thermoplastics Composites Use
in Rotating Machinery at Chevron
Refining
Benefits of implementing thermoplastic
composites:
– Improved Hydraulic Performance
– Greater Reliability
Thermoplastics Composites Use in
Rotating Machinery at Chevron Refining
Improved Hydraulic Performance • Greater throughput translates to profitable production increases
• Debottlenecking can allow one pump to do the work of two
Examples:
• Retrofitted hydraulic power recovery turbine with thermoplastic
composite wear rings and bushings enabled an additional 440 gpm,
resulting in an $800,000 annual production increase
• Retrofitted pump was able to perform the duty of a turbine driven
spare, resulting in elimination of 12,000 lb/hr steam vent, at an annual
savings of $200,000
Thermoplastics Composites Use in
Rotating Machinery at Chevron Refining
Greater Reliability • Greater reliability means:
• Fewer Lost Profit Opportunities
• Lower maintenance costs
• Less Equipment downtime
Example:
• Multi-stage pump with all metal wear rings was damaged from upset-
related severe internal rubbing. Cost of repairing the pump was
~$50,000 and took 2 weeks.
• After installation of the composite-made wear rings & bushings,
similar dry-run incident was repaired in 2 Days at a cost of ~$5,000
Thermoplastics Composites Use in
Rotating Machinery at Chevron Refining