Calgary Pump Symposium 2015
Engineered Mechanical Seal Design with
Diamond Face Technology in different Pump Applications
Nikolaus Necker
Calgary Pump Symposium 2015 1
Calgary Pump Symposium 2015 Calgary Pump Symposium 2015
Nikolaus Necker Nikolaus Necker is Senior Expert for Engineered Mechanical Seals at EagleBurgmann Germany GmbH & Co. KG, Wolfratshausen, Germany. He is responsible for the application engineering in all kind of Oil and Gas services. His job includes sales and applications of sealing technology for pumps world-wide (On- and Offshore) since he started with Burgmann in 1990. Nikolaus Necker has a Master of Engineering (Mechanical Engineering, 1989) from the Munich University of Applied Sciences.
Presenter
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Experience in Venezuela
In an Upstream facility operations located on Zuata´s field, in the Orinoco´s
Belt. EHO (Extra Heavy Oil) is produced with 8°API with high viscosity. Today,
520 horizontal wells producing in average 125.000 BPD of EHO, diluted with
naphtha up to 17°API, in order to enhance the performance of PCP ´s used to
lift the crude from downhole.
This Diluted Crude Oil (DCO) in mixture with produced gas is pumped from
clusters to a main station with Multiphase Pumps. In the Main Station DCO is
degassed and dehydrated. Then DCO is pumped to downstream facilities.
115000 BPD water is pumped for injection, and gas is used as a fuel to
generate electricity and heat for the process.
Clients experience with sealing systems for these Multiphase Pumps is based
on Twin Screw Pump technology with two different Flush Plans,
- with Single Seal with API-Flush Plan 32 and
- with Dual Seals with API-Flush Plan 54.
Calgary Pump Symposium 2015
Pump type: MW Twin Screw type
Installed Seal type: Single API682 Type A
Materials: AQ1VMG1
(hard – soft)
API Flush Plan: 32 + 62
Speed: 500-1800 rpm
Process fluid: Water, Oil, gas mixture with
sand particles
Plan 32 Flush fluid: Diluent (Naphtha)
Problem: Short seal life due to the
high sand content!!
API-Plan 32
flushrate 2 gpm
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The original Single Mechanical Seal
Calgary Pump Symposium 2015
P&ID
Flush is injected into the seal chamber from an external source.
FI Q/D
Pressure
Indicator
Temperature
Indicator
Control
Valve
Valve,
Normally Open
Flow Indicator
(Optional)
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API 682 Piping Plan 32
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The Single Mechanical Seal problem
• Field production is handled with many
multiphase pumps
• Seal life until 2012 was > 3 years!
• Due to early production and adding of
new wells sand content has increased
dramatically!
• Pump was stopped every 3 months due
to wear caused by the sand!
Calgary Pump Symposium 2015
Severe damage of the seal faces due to solids
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… errosion by sand in the
seal cavity ……
Calgary Pump Symposium 2015
Same field experience with hard faces – short life
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Heavy errosion of metal parts
even with special seal face
materials !
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The Solution - Single Slurry Seal Arrangement with
Diamond Face Material
The seal cartridges, installed in March 2014
Calgary Pump Symposium 2015
Same application - The Dual Seal Arrangement
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* Double seal in tandem arrangement
* Face material Combination hard-hard faces
* Barrier Fluid Pressure set point 41 barg
* Seal chamber Pressure from 6 to 34 barg
* Maximum operating temperature of 90°C
The high suction pressure at MPP´s seal chamber in combination with high
temperature from the reservoir and gas compression causes distortions at the
seal faces and got in contact on the outer diameter, face heating amplifies this
effect.
Seal inspection showed, that the high barrier fluid pressure of the API Plan 54,
caused bending of the seal faces and contact at internal diameter too.
Due to pressure peeks on suction side of the pump, reverse pressure
happened and sand entered the sealing gap and into the loop of the API Plan
54 system.
Calgary Pump Symposium 2015
API 682 Piping Plan 54
P&ID
Pressurized external barrier fluid reservoir or system supplying clean fluid to the seal
chamber. Circulation is by an external pump or pressure system. System pressure is higher
than the process pressure being sealed. This plan applies for Arrangement 3 seals.
LBO LBI
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External
Pressure
System
- Pressurization
- Lubrication
- Cooling
- Circulation
- Compensation
of leakage
Calgary Pump Symposium 2015
Diamond properties
HF- CVD Diamond deposition
Tribological performance
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The solution for both pumps - DiamondFace
… the microcrystalline material for mechanical seals
Fraunhofer
Condias
Calgary Pump Symposium 2015
Introduction – Conventional sealface materials in
Crude oil pumps
Crude oil,
water,
SSiC polished
5µm 5µm
Materials: - SSiC; Si-SiC; TC
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Calgary Pump Symposium 2015
Crude oil,
water,
sand, gas
Introduction – DiamondFace in multiphase
application
Microcrystalline Diamond Material
Substrate: - SSIC; Si-SIC
Layer: - microcrystalline diamond
- both faces
- chemical bonding
- film thickness 8µm
- grain size 2-5µm
5µm 5µm
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Calgary Pump Symposium 2015
Diamond properties
DiamondFace
… the micocrystalline material for mechanical seals
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Calgary Pump Symposium 2015
Chemical bonding => Superior diamond film adhesion
Cross section prepared by
Focused Ion Beam (FIB) cutting
SiC
Diamond
Ultimate hardness of diamond / Excellent wear resistance
Superior thermal conductivity
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Real Diamond properties
Calgary Pump Symposium 2015
Diamond properties – Crystalline Diamond is not DLC Coating
Amorphous “Diamond Like
Carbon” (DLC) coating Crystalline Diamond
Top view
Querschnitt
Top view
Cross section Cross section
10000 HV
1150 Gpa
2000 W/mK
1000 … 4000 HV
30…220 GPa
0,1…10 W/mK
Hardness
Young’s modulus
Thermal conductivity
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Calgary Pump Symposium 2015
Diamond properties
Diamond deposition
DiamondFace
… the micocrystalline material for mechanical seals
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Diamond deposition - Hot Filament Chemical Vapor
Deposition (CVD-Process)
Pressure, Energy, Gasflow, Gasphase,… Gas atmosphere
at vacuum
Hydrogen
99%
Methane
1%
Activation due
to hot filament T2000°C
+
T ~ 800°C
Deposition of
Diamond
(≈0,2 µm/h)
Calgary Pump Symposium 2015
Diamond properties
Diamond deposition
Diamond different test results
DiamondFace
… the micocrystalline material for mechanical seals
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First tests with Diamond Material in
water – air mixtures
Single Seal Arrangement – unbalanced seal design
• Single stage centrifugal pump
• Medium water / air
• Discharge pressure 16 bar
• Suction pressure 13 bar
• Pressure to be sealed 14 bar
• Fluid temperature 25 °C
• Sliding speed 10 m/s
• Speed 3000 rpm
Calgary Pump Symposium 2015
Test Results – under poor lubrication conditions
(actual 2500h)
SiC-SiC material
DiamondFace®
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Second Application - Crude Oil Pipeline, Brazil
Calgary Pump Symposium 2015
Several pumping stations
Heavy crude oil, up to 500 cSt, plus CO2
Several BB3 and BB1 pumps
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Crude Oil Pipeline Pumps
Mechanical Seal
Cartridge Mechanical Seal
Cartridge
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Crude oil characteristics
Crude oil contains:
Crude of different density and viscosity (API gravity grades)
Mixture of different Hydrocarbons
Saline Water
Paraffin Wax
Natural Gas, including CO2 or H2S
Debris, Sand, Asphalt
Calgary Pump Symposium 2015
The Single Seal cross-Section
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The Mechanical Sealing Concept – Single Seal
Arrangement
The seal cartridges, installed in May 2012
With Diamond face material
Calgary Pump Symposium 2015
Summary
DiamondFace -
A Key to Improve Mechanical Seal Reliability in Critical Applications
Tolerant to poor lubrication and temporary dry running
Excellent wear resistance in slurry and abrasive suspensions
Reduced friction, energy saving
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Third Application – Emulsion Pumps Canada
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The challenging application
SAGD-process in Fort Mc Murray
Bitumen / Emulsion Pumps
Abrasive, high Pressure & Temperature operating conditions
API Standard 610 BB2 pumps, different seal chamber pressures DE/NDE, 5-27 bar
The operator was not satisfied with the reliability of the original seals
A Slurry seal design API 682 type ES,
dual pressurized mechanical seal was proposed
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The sealing solution –
Dual pressurized slurry seal design
Dual pressurized: Piping Plan 53A / 54
Special seal face materials:
Tungsten Carbide vs SiC/C mix
Barrier fluid: high grade synthetic oil
Process fluid: bitumen / water emulsion
with hydrogen sulphide (sour), salt, and
sand.
Viscosity 51 cP
Specific gravity 0.89
Temperature: 165 °C normal, 180 °C
max.
Sand concentration is typically < 5 % by
volume, < 300 micron particle size
Speed: 3.600rpm
Calgary Pump Symposium 2015
API 682 Piping Plan 53A
31
External piping provides clean barrier-fluid for the seal faces of a pressurized dual seal
arrangement. Pressurized barrier fluid reservoir provides pressure to the closed loop circulation
system. Flow is maintained by an internal pumping ring. Heat is removed from recirculation
system by air or water -cooled heat exchanger
LBO LBI
Barrier
Fluid
Makeup
Pressure
N2 source Pressure
Switch Low
Pressure
Indicator
Check
Valve
Level
Switch Low
Cooling water
connection
P&ID
Calgary Pump Symposium 2015
API 682 Piping Plan 54
P&ID
Pressurized external barrier fluid reservoir or system supplying clean fluid to the seal chamber.
Circulation is by an external pump or pressure system. System pressure is greater than the
process pressure being sealed. This plan applies for Arrangement 3 seals only.
LBO LBI
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External
Pressure
System
- Pressurization
- Lubrication
- Cooling
- Circulation
- Compensation
of leakage
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The mechanical seal performance
First installations in 2006, since then continous improvement processes, which
result in significant higher MTBR of mechanical seals
Proven Engineered seal design was installed in multiple other (SAGD- and
mining-) installations. Similar seals used for Transfer Pumps
Preferred seal design for Transfer Pumps in SAGD plants
Specified as preferred supplier for these applications by the End User
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Conclusion
Engineered Mechanical Seals are sealing multiphase mixtures, extra-
heavy crude oil and hot emulsions successfully using slurry seal
designs in combination with API-Plan 31, 32 and 53
Diamond Face Technology is improving the seal performance
significantly
Dual Mechanical Seals are used almost always in combination with
API-Plan 53B, 53C or 54
Correct installation and operation of the seals and their auxiliary
systems are the key-factors for a long seal life time
Calgary Pump Symposium 2015
Thank you!
Any questions ??
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