Post on 01-Apr-2018
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Crude Preheat Management for Challenged and Unconventional Crudes
COQA Meeting San Antonio7th March 2013
Greg Savage
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Increased Fouling Potential From New Crudes2
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Energy Management and Fouling Control OverviewFouling problem solving:
Evaluate mechanical, operational, and chemical root causes
Identify fouling mechanism
Select solution
Monitor Performance
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LOCATION
Crude Preheat Exchangers
Crude or Vacuum Furnace
Gas Oil Loop
Resid Exchangers
Tower Tray / Packing
Asph
alte
nes
Cor
rosi
on
Inor
gani
c sa
ltsPo
lym
er g
umC
okin
g
Observed Fouling Locations in the Crude Unit
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WHAT CAUSES FOULING?Mechanical – Operational – Chemical Causes
MOC
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Mechanical & Operational Causes
Poor tank farm practices Incompatible Crude blending Slops containing ash, gums, coke, etc.
High skin temperatures or heat fluxes
High solids level in crude
Poor desalting
Other possible causes Low exchanger velocities Chemical additive treatment
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Common Fouling MechanismsCrude Preheats – Unconventional Crudes
Deposit Cause
Asphaltenes Destabilization of asphaltenes
Inorganic Solids High solids level in unconventional crudes
Polymeric gum Co-processing reactive streams or chemical additive treatment
Coke Dehydrogenation of asphaltenes & PNA’s
Inorganic salts Poor or no desalting, amines
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HOW DO WE FIND THE ROOT CAUSE?
MOC
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Root Cause Analysis: Fouling Mechanism
Deposit analysis Identify and quantify elemental components Interpret organic and inorganic nature
Stream characterization Identify and quantify fouling precursors
Fouling simulation and Chemical selection Simulate process fouling (mechanisms) Screen chemicals
Together help describe probable fouling mechanisms
MOC
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Deposit Analysis Summary10
Analysis 80% Eagle Ford 25% Canadian75% Domestic light
Organic Materials 11.0% 95.2%Soluble Organics 5.0% 31%
Coke, polymers 6.0% 64.2%Inorganic Materials 89.7% 4%
Iron Salts: 40.6% 2.4%Other Salts including Volatile Salts: 49.1% 1.6%
Carbon/Hydrogen Mass Ratio 10.0 11.2
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Bakken Stream Analysis
The Bakken Crude is Low in Asphaltenes and Metals
High Solid Nos.
Low in Aromatics
Highly Paraffinic
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ANALYSIS Flashed Crude Oil
Al 0.3 ppmCu / Fe 0.06 / 4.1 ppmNi / V 0.61 / 0.22 ppmNa / K 4.1 / < 0.2 ppm
Ca 0.6 ppmMg < 0.2 ppm
Solids 39 lbs / MbblsAcid No. 0.07 mg KOH/g
Naphthenic Acid < 0.1 mg KOH/g
Asphaltenes 0.1 wt%Aromatic 8.8 wt%Paraffin 37 wt%Polar 1.4 wt%
Aromatic (NMR) 14.6 mole%
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75% Eagle Ford Stream AnalysisHigh solids level made up of inorganic material
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Analysis Filtered TotalAl 0.17 ppm 4.9 ppmCa 1.4 ppm 15 ppm
Cu / Fe 0.16 / 3 ppm 0.21 / 16 ppmMg < 0.12 ppm 1.6 ppm
Ni / V 8 / 22 ppm 8 / 22 ppmNa / K 0.4 / < 0.3 ppm 34 / 1.2 ppm
Cl 59 ppmSolids 150 lbs/MbblsWater 0.2 vol %BS&W 0.4 vol %
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Laboratory Furnace Fouling Simulation
HLPS Test Equipment Bakken fouling
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Characterization Of Deposit From HLPS
Analysis Wt %Fe 18.0S 17.0
Ca 0.5C 51.0H 5.0N 0.8
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Left to Right: Blank, Products A, B, C, D Elemental Maps Iron = red, Sulfur = green, Phosphorus = blue
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Crude Stability Index (CSI) 20+ years
0
2
4
6
8
1 0
1 2
0 8 1 0 1 2 1 4 1 6 1 8 2 0
Volume of Aliphatic Solvent
Solvent Dilution
Flocculation Point
Solvent Dilution
Commencement of Solvent Addition
0
2
4
6
8
1 0
1 2
0 8 1 0 1 2 1 4 1 6 1 8 2 0
Volume of Aliphatic Solvent
Solvent Dilution
Flocculation Point
Solvent Dilution
Commencement of Solvent Addition
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Component and Blend CSI indicating Potential Incompatibility
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Crude Stability Determination: Blends
28.644.5
22.6
CSI
Unconventional blend with few asphaltenes
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Assessment of Shale Condensate on Crude StabilityIdentify blend instability region
0
10
20
30
40
50
60
70
80
90
100
0 10 20 30 40 50 60 70 80 90 100
Cru
de S
tabi
lity
Inde
x
Percentage of WCS in Bakken
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Stability Change with Process Temperature
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Asphaltene Dispersant Performance using CSI
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Intrinsic Stability Analyzer• Intrinsic stability “S” concept as per ASTM D 7157
• Simple to operate, user friendly
• Results obtained in about 20 minutesS = StabilitySo = Solvency Power of OilSa = Asphaltene Solubility
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Blending Order Stability Study
?
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Fouling Control Strategies
Do nothing
Mechanical options
Operational options
Evaluate chemical solution(s) Understand mechanistic function of products
Improved monitoring Field support tools
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Tracking treatment performance
Midcontinent Domestic with Canadian
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Tracking treatment performance25
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Acknowledgements
Gregg McAteer
Laura Copeland
Sam Lordo
Keith Gawrys
Christopher Russell
Michael Braden
John Garcia
Kailash Sawhney
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Disclaimer: The contents of this document are, to the best of our knowledge, accurate at the date ofpublication. We shall not be liable for any loss or damage whatsoever resulting from reliance on its contents. Allwarranties as to fitness for purpose or otherwise (howsoever made or implied) in respect of this publication areexcluded.
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Questions