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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.


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


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


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!


Severe damage of the seal faces due to solids

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… errosion by sand in the

seal cavity ……


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


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.



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


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


Introduction – Conventional sealface materials in

Crude oil pumps

Crude oil,

water,

SSiC polished

5µm 5µm

Materials: - SSiC; Si-SiC; TC

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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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Diamond properties

DiamondFace

… the micocrystalline material for mechanical seals

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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


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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Diamond properties

Diamond deposition

DiamondFace



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)


Diamond properties

Diamond deposition

Diamond different test results

DiamondFace


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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


Test Results – under poor lubrication conditions

(actual 2500h)

SiC-SiC material

DiamondFace®

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Second Application - Crude Oil Pipeline, Brazil


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


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


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


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


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


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


API 682 Piping Plan 53A

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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



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

32

External

Pressure

System

- Pressurization

- Lubrication

- Cooling

- Circulation

- Compensation

of leakage


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


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


Thank you!

Any questions ??

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